Glossary as it applies to the eye and refractive cataract and laser surgeries.
Aberration Focusing errors of the eye. Glasses correct lower order aberrations such as sphere, cylinder, and axis.
Aberrometer A device that such as the LADARWave™ that measures lower- and higher-order aberrations.
Ablate To remove. The term is used in laser surgery such as LASIK-to removal corneal tissue to correct a refractive error.
Ablation A surgical procedure to removed tissue, e.g., removal of corneal tissue during excimer laser vision correction.
Ablation depth The depth of tissue removed during excimer laser vision correction.
Ablation zone The area of corneal tissue removed during excimer laser surgery.
Accommodation The ability of the eye to change its focus from distance to near.
Accommodative IOL IOL that mimics the eyes ability to accommodate. As of 2007, the Crystalens® made by Eyeonics is the only FDA-approved accommodating IOL.
Acuity Clearness as in visual acuity. The most commons method of measuring vision is the Snellen Visual Acuity.
Acular® Ketorolac tromethamine nonsteroidal antiinflammatory eyes drops used after PRK/LASEK to reduce pain. Also, used to control inflammation after cataract and other ocular surgery.
ACIOL Abbreviation for anterior chamber IOL.
Adnexa Accessory structures of the eye, including the eyelids, lacrimal apparatus, etc.
After cataract Another name for capsular haze.
Age-related macular degeneration A leading cause of loss of central vision in seniors. There are two main groups, dry and wet. There are treatments for wet age-related macular degeneration.
AK Abbreviation for astigmatic keratotomy.
ALK Abbreviation for automated lamellar keratoplasty.
Alpha Blockers Flomax and other alpha-blockers increase the difficulty of cataract surgery, particularly if the ophthalmologist does not know that the patient is taking or has been taking these medications.
ALT Abbreviation for argon laser trabeculoplasty.
Amblyopia Poor vision due to lack of development of the visual system to the brain. The eye structure and function is normal. Layterm is lazy eye.
Ametropia The presence of a refractive error in the eye such as myopia, hyperopia, or astigmatism.
Amsler grid Handheld chart featuring horizontal and vertical lines, usually white on black background, to test for central visual field defects.
Angle The drainage area of the eye formed between the cornea and the iris named for its angular shape.
Angle closure glaucoma Acute onset glaucoma with severe eye pain, blurred vision, nausea, and vomiting.
Aniseikonia A difference of the image size on the retina of each eye. It is due to anisometropia.
Anisometropia A difference in the refractive error of two eyes.
Anterior chamber The area between the cornea and lens filled with aqueous humor.
Anterior chamber IOL Aphakic IOL is placed with iris or angle support. An IOL placed in the anterior chamber in front of the iris. This done infrequently at the time of cataract surgery when all capsular support is lost and a sulcus fixation of the IOL can not be achieved. See capsular fixation and sulcus fixation.
Anterior vitrectomy Removal of the anterior vitreous most commonly at the time of cataract extraction when a complication of vitreous loss is encountered.
Antibiotic medication A drug used to treat or prevent infection. It is commonly used after refractive, cataract, or other ocular surgery.
Antiinflammatory medication A drug that reduces inflammation caused by surgery, trauma or disease. It is commonly used after refractive, cataract, or other ocular surgery.
Antioxidants - Substances that destroy or neutralize free radicals, molecules that have been implicated as one causative factor in the stimulation of abnormal cellular reproduction (cancer) and cellular destruction (aging).
Antireflective coating Coating on the front or back of glasses lenses, which minimizes glare for patients.
Aphakic Not having a lens. This was the condition before IOL were inserted after cataract surgery.
Aqueous humor A transparent fluid occupying the anterior chamber and maintains eye pressure.
Array® IOL The first multifocal presbyopia correcting IOL. Now replaced by the ReZoomTM for most cases. Low-power Arrays are available for extremely myopic eyes and as a secondary piggyback IOL for psuedophakic eyes.
Argon laser trabeculoplasty Shortened term usually for a-scan biometry. See biometry.
ARMD Abbreviation for age-related macular degeneration, a leading cause of loss of central vision in seniors. There are two main groups, dry and wet. There are treatments for wet age-related macular degeneration.
A-scan Shortened term usually for a-scan biometry. See biometry.
Aspheric IOL IOL with aspheric properties. Most IOLs are not aspheric.
Aspheric Lens A lens designed to adjust for diopteric power lens over its entire diameter. This results in the light coming to focus at the same point. Spheric lens focuses light from the periphery and the center of the lens to a different position resulting in a blur. All expensive camera lenses are aspheric.
Asthenopia Eyestrain caused by a need for glasses, incorrect glasses, or from an imbalance between the two eyes.
Astigmatic keratotomy A procedure use to correct astigmatism by making an incision into the cornea.
Astigmatism A focusing error that results in blurred distant and/or near vision. This is often caused by the cornea being oval like a football rather than spherical like a basketball. The amount of astigmatism you have will appear in the second number of most glasses prescriptions, i.e., -4.00 –1.00 x 30o or –5.00 + 1.00 x 120o. In both cases, the astigmatism is one diopter. These prescriptions are equivalent and differ in the format written. The first is written in minus cylinder and the second in plus cylinder.
Atropine Use to paralyze the iris sphincter and ciliary body. Mainly used for cycloplegic. Effect is long lasting from two to 14 days. Effect is usually much less when used after surgery or if there is significant inflammation.
Autoimmune Disease A condition where the immunological system of the body attacks itself and results in inflammation or swelling of parts of the body, such as muscles, joints, and blood vessels. You should discuss any history of this condition with your doctor before having excimer laser surgery.
Automated lamellar keratoplasty A microkeratome is used to create a flap in the cornea followed by a second power cut that corrects the refractive error. The combination of the flap creation with the precise ablation of the excimer laser for the power cut is LASIK.
Automated perimeter A computer driven device to plot visual fields defects.
Axis In ophthalmology, the direction of the astigmatism.
Azopt Alcon's trade name for brinzolamide suspension, a topical carbonic anhydrase inhibitor the the treatment of glaucoma.
Background diabetic retinopathy See nonproliferative diabetic retinopathy.
BAK Abbreviation for benzalkonium chloride.
Bandage contact lens A soft contact lens placed on the cornea after surgery to make it more comfortable and to help in healing.
Band keratopathy Pathological deposition of calcium in the superficial cornea associated with chronic inflammation.
BCVA Abbreviation for best corrected visual acuity.
Bell's palsy Paralysis of the facial nerve which also controls the eyelids. Eyelids may not close properly leading to dryness. Most cases of Bell's palsy recover.
Benadryl Trade name for diphehydramine, an over-the-counter antihistamine use to treat allergic and hypersensitivity reactions.
Benzalkonium chloride A preservative used in many ophthalmic drops. A cause of allergies in some and may exacerbate dry eyes.
B-Scan Ultrasound that provides a cross-sectional view of tissues. It is usually used when there is not a view of the retinal due to an opaque cornea, dense cataract or vitreous hemorrhage or other vitreous opacity.
Best corrected visual acuity The best possible vision with glasses when measured with Snellen Visual Acuity.
Beta-carotene Member of the carotinoid family of vitamins, a precursor to vitamin A. They are beneficial to the eye.
Bifocals Lenses containing two prescriptions, one for distance and one for nears.
Binocular vision Simultaneous use of the two eyes. Normal binocular vision yields a stereoscopic image and depth perception.
Biometry measurement Measures the dimensions of the eye and its internal structures. Most commonly, the information is used to determine the IOL power for cataract surgery and refractive lensectomy. Pachymetry is measurement of the corneal thickness of the eye by similar techniques for refractive surgery.
Bleph 10 Brand name for sulfacetamide antibiotic.
Blephamide Brand name for eye medication with prednisolone and sulfacetamide antibiotic.
Blepharitis An inflammation of the eyelids.
Blind spot An area in the field of vision where nothing is seen. This is due to the optic nerve, and there are no photoreceptors in this area.
Botox Allergan's trade name for botulinum toxin A. It initially was used to temporary paralysis of muscles. Now, its use includes temporary reduction of facial wrinkle to treatment for migraines.
Branch retinal artery occlusion A blockage of a branch of the central retinal artery usually at the crossing point with a branch retinal vein. Usually caused by an embolus, such as a cholesterol plaque. This results in a loss of visual field in the distribution of the branch artery. A vascular work up is usually indicated.
Branch retinal vein occlusion A blockage of a branch of the central retinal vein usually at the crossing point with a branch retinal artery. This is age related and associated with hypertension.
Breakup time Measurement of tear function. The time it takes from a blink to a dry spot in the precorneal tear film. Less than 10 seconds is abnormal and usually indicative of dry eye syndrome.
Broad beam laser Laser beams can range from 9 mm to less than 1 mm in size. The first excimer lasers were broad beam and used a laser beam of 6 to 8 mm in diameter. Shutter mechanisms and slits are used with some of these lasers to control the size and dimensions of the laser beam.
C3F8 (perflouropropane) An expansile gas used to repair retinal detachments.
C8F18 (perflouroctane) A heavier than water liquid use in the repair of retinal detachments.
Capillary dropout Loss of retinal capillaries in vascular diseases of the retina. Most common in diabetic retinopathy, branch retinal artery occlusion, and branch retinal vein occlusion.
Calibration The process of measuring and setting the laser to the needed energy for accurate tissue removal. Some machines sculpt a PMMA plastic button to be measured by optical instruments, and others employ a 1-micron thick foil as a method of calibration.
Can opener Capsulectomy technique made by numerous single cuts in the anterior capsule. An earlier inferior technique used prior to continuous curvilinear capsulorhexis.
Capsular bag The remains of the lens capsule (see lens capsule) removal of the lens or cataract. An IOL is inserted into the capsular bag. Certain types of IOLs, such as accommodating IOLs, can not be implanted if the capsular bag is damaged during cataract surgery
Capsular fixation The fixation of an IOL within the lens bag. See capsular bag, sulcus fixation, and anterior chamber IOL.
Capsular tension ring A device used to support the capsular bag implanted at the time of cataract surgery when zonular dehiscence is present. (Loss of support structures from the ciliary body to the lens. This both supports the lens and transmits the forces for accommodation.)
Capsulectomy Removal of part of the anterior capsule for extracapsular and phacoemulsification cataract surgery. See continuous curvilinear capsulorhexis and can-opener capsulotomy.
Continuous curvilinear capsulorhexis Capsulectomy technique by a continuous curvilinear tear rather than with multiple single tears, such as the can-opener technique.
Capsular haze A thin film of scar tissue that occasionally forms on the posterior capsule (the posterior part of the capsular bag) behind the intraocular lens implant following cataract surgery. It is treated a Yag laser. The laser creates a small opening in the scar tissue the the posterior capsule. Treatment is recommended three months after cataract surgery or when the IOL haptic's are secured in the capsular bag.
Caruncle Pink fleshy conjunctival tissue in the nasal corner of the eye.
Cataract A clouding of the lens of the eye. Vision becomes blurred as the cataract progresses. About half of the people by the age 55 over have cataracts.
Cataract surgery The surgery to remove cataracts. Almost 3 million cataract surgeries are performed in the United States each year.
Central islands A manageable complication of excimer laser vision correction where the laser beam fails to remove a portion of cornea usually in the center of the area to be removed. If one views the concave area of the ablation like a lake one can imagine an island sticking up in the center, the visual symptoms would be monocular double vision or distortion, just as you would expect if there were an irregularity in the surface of your glasses. This has largely been prevented with advanced technology excimer lasers.
Central retinal artery The main artery entering the eye. A branch of the ophthalmic artery that enters the eye through the optic nerve.
Central retinal artery occlusion Blockage of the main artery into the eye that usually results in permanent visual loss.
Central retinal vein The main vein leaving the eye through the optic nerve.
Central retinal vein occlusion Blockage to the main vein leaving the eye that usually results in severe visual loss. Some treatments are available depending on severity.
Chalazion A chronic inflamed mass in a meibomian gland of the eyelid. It can result from an untreated internal hordeolum, an acute inflammation of the meibomian gland.
Chemosis Swelling of the conjunctiva.
Chiron Manufacturer of excimer laser Technolas 217A excimer laser. Acquired by Baush and Lomb.
Choroid The vascular layer beneath the retina.
Ciprofloxan A third-generation fluroquinones. Fourth-generation fluroquinones now in use.
CK Abbreviation for conductive keratoplasty.
Clear lens extraction A surgical procedure to remove the natural lens and replace with an intraocular lens. This is the same procedure as a cataract surgery. In cataract surgery, the lens is no longer clear. A preferred term is refractive lens exchange since all lens are not clear and yet do not qualify for insurance reimbursement for cataract surgery. This procedure can correct refractive errors and presbyopia.
CME Abbreviation for cystoid macular edema.
Color blindness A lack of sensitivity to certain colors.
Collagen vascular disease A condition that may result in inflammation or swelling of parts of the body, such as muscles, joints, and blood vessels. Examples are lupus and rheumatoid arthritis. You must inform you surgeon if considering laser vision correction surgery.
Concave lens A lens with a hollow shape like the inside surface of a ball. Concave lenses are minus (-) power lenses and are used to correct myopia or nearsightedness.
Coma aberration Off axis image distortion. It appears comma-shaped instead of dot-like.
Conductive keratoplasty A radiofrequency probe is inserted into the cornea to change its refractive power. It can only correct hyperopia and presbyopia.
Conjunctiva The delicate mucous membrane that lines the eyelids and covers the white surface of the eye. The conjunctiva joins the eyeball at the edge of the cornea (limbus). Contradictions: Any special condition that results in the treatment not being recommended.
Conjunctivitis An inflammation of the conjunctiva called red or pink eye. It may be caused by an allergy, infection from a viral or bacterial origin, or a toxic chemical.
Convergence Eye turning in to focus on a near object.
Contrast sensitivity A measure of the ability of the eye to detect small lightness differences between objects and the background in daylight and in dim light. For example, black lines on a gray background are easier to see than gray lines on a gray background. Objects in daylight are also easier to see than in dim light. Contrast sensitivity testing is a way to determine how well patients can see in poor contrast conditions such as very dim light, rain, snow, and fog. Contrast sensitivity may be reduced after excimer laser vision correction.
Convex lens A lens with a bulging surface like the outer surface of a ball. Convex lenses are plus (+) power lenses and are used to correct hyperopia or far sightedness and for reading glasses as needed in presbyopia.
Cornea The transparent front window of the eye. It provides 70% of the eye’s refractive power. It is approximately 500 microns in thickness. Its thickness is an important factor in laser vision surgery. There must be adequate corneal tissue for the ablation zone and depth require for the refractive error and pupil size. The cornea can be considered to have five layers:
- Corneal epithelium
- Bowman's layer
- Corneal stroma
- Descemet's layer
- Corneal endothelium
Corneal endothelium The inner layer of cells on the inside surface of the cornea. It maintains the clarity of the cornea by removing fluid from it.
Corneal epithelium The outer surface layer of the cornea, like the epidermis or outer layer of the skin. This layer is removed in PRK and moved aside in LASEK.
Corneal flap A thin slice of tissue on the surface of the cornea made with a microkeratome at the beginning of the LASIK procedure or with the Intralase during the IntraLASIK™ procedure. This flap is folded back before the laser shapes the inner layers of the cornea.
Corneal haze An opacification or cloudiness of the normally clear cornea. Any buildup of inflammatory infiltrates (white blood cells), extra moisture, scar tissue, or foreign substances (like drugs) can cause a clouding of the cornea. Most types of haze will disappear with time or drug treatment. Rarely, a permanent haze or scars can form.
Corneal map See corneal topography.
Corneal relaxing incisions Incisions made in the corneal to decrease astigmatism.
Corneal swelling An abnormal fluid buildup in the cornea. This condition is usually temporary with no significant effect on vision.
Corneal topography A detailed colored map of the front surface of the cornea. It is used to detect abnormalities of the surface contour and curvature of the cornea. It a very important test used to diagnosis conditions, such as keratoconus, which can be a contraindication to excimer laser surgery.
Corneal wrinkle Usually a temporary appearance of fine white lines in the cornea due to swelling. This can occur after LASIK. They should be removed if persistent and affecting vision.
Conventional LASIK LASIK surgery that uses and eyeglass prescription to plan the surgery.
CRIs Abbreviation for corneal relaxing incisions.
Cross-eyes Eyes turn in toward the nose. See esotropia.
Crystalens The first accommodating IOL approved by the FDA.
Crystalline lens The natural lens of the eye. It starts out clear and flexible, and with age, it first looses it flexibility (accommodation) and later clarity (cataract).
CustomCornea® The trade name for LADARVision® 4000’s wavefront-guided custom ablation.
Custom LASIK Wavefront-guided custom laser vision correction such as CustomCornea
Cycloplegic refraction To measure the refractive state of the eye without the effects of accommodation. A cycloplegic drop is used to temporarily paralyze the accommodation muscle. An important step prior to LASIK or other laser vision correction surgery. Also, used in children since they have a high accommodative amplitude.
Cyclogyl Trade name for cyclopentolate.
Cyclopentolate Eye drops that dilate the pupils and paralyze accommodation.
Cylinder The amount of astigmatism in an eye.
Cystoid macular edema A swelling in the macular area. A relatively common postoperative complication of cataract surgery. It is treated with NSAIDs and steroids. It can also occur with uveitis, retinal vascular diseases and other causes of fluid accumulation in the macula.
Dacryocystitis Inflammation of the tear sac. Leads to tearing. It can lead to a local abscess if severely infected.
Dellen Localized corneal thinning due to dryness.
Depth perception The ability to determine the relative distance of objects. To be able judge which object is closer. Also called steropsis.
Detached retina The separation of the retina from the choroid. Early signs are flashes and floaters. This is an emergency and needs to be surgically repaired as soon as possible.
Detachment Abnormal separation of tissues.
Deturgescence The decrease in swelling.
Diabetic retinopathy Retinal changes from poorly controlled or long standing diabetes. Leading cause of blindness in patients less than 65 years old.
Diamox Trade name for acetazolamide. A pill used to lower intraocular pressure used for glaucoma.
Dilated pupil Enlarged pupil from drugs, trauma, or tumors. Pupils are frequently dilated during an eye examination to view the retina and optic nerve.
Diplopia Double vision or seeing double usually with both eyes open as in binocular diplopia, but can be with only one eye as in monocular diplopia.
Diopter It is the unit of measurement for optical lenses use to correct the refractive error of an eye. It is used to describe the amount of nearsightedness, farsightedness, and astigmatism. A one diopter lens will focus parallel light rays one meter from the lens and a two diopter lens will focus 0.5 meter from the lens. A plus (+) 1.0 diopter lens is convex and will converge the light rays so they focus as a visible image one meter past the lens. A minus (-) 1.0 diopter lens is concave and will diverge or spread light. The minus lens will not actually focus as a visible image on an optics table. Its image is known as a virtual image and if the diverging rays were followed to their point of origin they would focus one meter in front of the minus lens. Most eyes are between +6.0 and -6.0.
Distortion In refractive surgery, an aberration in the optical systems resulting in glare, halos, shadowing, ghost images, and lack of crispness of vision.
Divergence The eyes turn outward.
Dominant eye The preferred eye for various visual tasks. It is usually the same side and the dominant hand. Important for setting the eyes correctly for monovision. The dominant eye is set for distance and the nondominant eye is set for near.
Double vision See diplopia.
Drusen Abnormal deposits on Bruch's membrane. Frequently a sign of early macular degeneration.
Dry eye A syndrome characterized by corneal dryness due to decrease in tear production. It is more common in women and its incidence increase with age. It can occur as a complication of refractive surgery.
Descemet's stripping endothelial keratoplasty A new procedure where only the disease corneal endothelium is replace. A full thickness keratoplasty was performed prior to DSEK. Recovery was slow and high degrees of astigmatism was common.
DSEK Abbreviation for Descement's stripping endothelial keratoplasty.
Econopred Trade name for prednisolone acetate, a drug used to control ocular inflammation.
Ectasia A progressive thinning and budging of the cornea and can occur as a very rare complication of excimer laser vision correction surgery. This occurs in keratoconus.
Ectropion The outward turning of the eyelids. An aging change due to the sagging of the collagen fibers. This can lead to irritation or tearing of the eye.
Emmetropia Normal distance vision without glasses, no refractive error. The usual goal of refractive surgery.
Endo A prefix meaning within or inside.
Edema Swelling of tissue from excess fluid accumulation. Macular edema, swelling of the macular from retinal vascular disease such as diabetic retinopathy or from inflammation. Seen after cataract surgery. Most cases resolve some need topical antiinflammatory medications such as steroid or NSAIDs. Corneal edema from loss endothelial cell function.
Endophthalmitis An inflammation within the eye. Inflammation may be caused by organisms such as bacteria or may be sterile as in immune disorders. It is complication of intraocular surgery such as cataract surgery. It can be treated with surgery or injection of intraocular antibiotics if caught early.
Enhancement A subsequent laser treatment made to refine or improve the original visual result. It is important to appreciate that although refractive predictability is excellent at lower planned corrections, that predictability is reduced at higher corrections. Higher corrections and wider optical zones require deeper sculpting and consequently under correction and over correction are more common. Enhancement treatment by contrast is usually a small correction and usually has a highly accurate outcome.
Entropian The inward turning of the eyelids. This frequently causes irritation form the lashes rubbing on the eye.
Epithelial ingrowth A complication of LASIK wherein epithelial cells grow underneath the corneal flap. It should be removed if it progressives and affects vision, or creates other problems.
Excimer laser A “cold” laser energy produced by several rare gas-halide mixtures. The term excimer comes from the concept of an energized molecule with two identical components or excited dimer (contracted to one word excimer). In excimer laser vision correction, the term has for practical purposes become synonomous with the argon-fluoride (ArF) gas version. The wavelength of an ArF excimer laser is in the far ultraviolet range at 193.
Esotropia Eyes turn in toward the nose.
Exotropia Eyes turn outward.
Exposure keratitis Corneal irritation from corneal drying from incomplete eyelid closure.
Eyeonics The company that developed Crystalens. Acquired by Bauch and Lomb.
Extracapsular cataract surgery An older cataract surgery technique requiring a larger incision and sutures. This technique was replace with small incision phacoemulsification as foldable IOLs became available.
Farsightedness The layterm for hyperopia or hypermetropia.
FA Abbreviation for fluorescein angiogram.
Femtosecond laser Laser used to make a flap for LASIK, cut the corneal for corneal transplant, make channels for Intact's, etc. Basically a laser scaple. Intralase is the first and only FDA-approved femtosecond laser.
Focusing error A condition in which your eye forms a blurred image on your retina. Examples are nearsightedness, astigmatism, and higher-order aberrations (complex focusing errors).
Flap Resection of tissue for reattachment, e.g., conjunctival flap, scleral flap, skin flap, etc. Corneal flap for LASIK or ALK.
Flap and zap A term meaning LASIK. Make the flap and zap with the laser.
FLAREX® - Fluoromethalone acetate 0.1% Corticosteroid eye drop used to reduce inflammation in excimer laser surgery, other ocular surgeries and ocular inflammation from other causes. It is used to decrease corneal haze and regulate healing response after PRK/LASEK. Manufactured by Alcon.
Flashes The sensation of light lasting a few seconds from vitreous traction on the retina. This traction may lead to a retinal tear and patients with flashes should be examined as soon as possible. Flashes lasting minutes may be a sign of migraine or cerebral vascular circulation problems.
Floaters Patient describe this symptom as cobwebs, hair, spots, spiders, etc, in their field of vision. This is caused opacities in the vitreous caused by degeneration. This is a common aging change. However, retinal tears can occur as the vitreous detaches from the retina. Retinal tears can lead to a retinal detachment. Patients with new floaters need an examination to rule out a retinal tear.
Fluorescein angiogram A test for evaluation of the retina and choroid. A fluorescein dye in injected into a vein and a series of photographs are taken as the dye travels through the eye. Use in retinal vascular disease such as diabetic retinopathy, retinal arterial and vein diseases, etc. Use in the diagnosis of age-related macular degeneration and macular edema.
FML® - Fluoromethalone 0.1% Corticosteroid eyedrop used to reduce inflammation in excimer laser surgery, other ocular surgeries and ocular inflammation from other causes. It is used to decrease corneal haze and regulate healing response after PRK/LASEK. Manufactured by Allergan.
FML FORTE® - Fluoromethalone 0.25% Corticosteroid eyedrop used to reduce inflammation in excimer laser surgery, other ocular surgeries and ocular inflammation from other causes. It is used to decrease corneal haze and regulate healing response after PRK/LASEK. Manufactured by Allergan.
Fovea The area of the sharpest vision in the macula.
Fundus Interior posterior surface of the eye. Includes the retina and optic nerve.
Ghosting Additional less distinct images surrounding the real image. A distortion of image due to irregular healing of the corneal surface.
Glare A condition in which patients see additional luster around lights. Patients with contacts lens can experience glare. It often occurs after refractive surgery and decreases with time.
Glaucoma An eye disease usually associated with high eye pressure that damages the optic nerve. It is progressive and can leads to loss of vision. It is commonly treated with glaucoma eye drops. The cornea becomes thinner after excimer laser vision correction and results in eye pressure measurements reading falsely low.
Halos A circular flares or rings of light that may appear around a headlight or other lighted object. This symptom may occur with contact lenses and after excimer laser surgery. Halos after surgery usually diminishes with time.
Haptic The nonoptical part of an IOL used to secure the IOL to the capsule, sulcus, iris, or angle.
Healon Trade name for sodium hyaluronate, a viscoelastic agent used in cataract surgery.
Herpes simplex A viral infection that can recur. This virus typically causes cold sores and/or vesicles to appear on the face or other parts of the body. The excimer laser can reactivate herpes simplex keratitis. You should discuss any history of this condition with your doctor before having excimer laser surgery.
Herpes zoster A viral infection that can recur. This condition is a reactivation of the chicken pox virus as an adult. Vesicles appear on only one side of the body. It can affect the cornea similar to herpes simplex. You should discuss any history of this condition with your doctor before having excimer laser surgery.
Hyperopia (hypermetropia) A refractive abnormality of the eye requiring a plus (positive or convex) lens for correction. Layterm is farsightedness. Farsighted people can see at a distance more clearly than they can see objects that are closer.
Hyphema Blood in the anterior chamber of they eye.
Hypotony Low intraocular pressure. Most commonly related to increased in filtration after glaucoma surgery, wound leak after ocular surgery, and retinal detachment.
Immunodeficiency disease A condition that compromises the body’s ability to heal. An example is acquired immunodeficiency syndrome (AIDS). You should discuss this condition with your doctor before having LASIK surgery.
Inflammation A tissue's reaction to trauma often with pain, heat, redness, swelling, and or loss of function. Inflammation may be caused by mechanical trauma such as surgery, infections by bacteria or viruses, and by immune reactions, and other causes.
IntraLASIK™ Use of an Intralase Femtosecond Laser to created a flap in LASIK surgery rather than using a microkeratome.
Intraocular lens An artificial lens to replace the cataract after cataract surgery.
Intraocular pressure Pressure within the eye. Elevated intraocular pressure may be a sign of glaucomas.
IOL Abbreviation for intraocular lens.
IOLMaster A noncontact optical biometry. The most accurate method for determining axial length for cataract surgery. Made by Zeiss.IOP Abbreviation for intraocular pressure.
Iridotomy A surgical opening made in the iris to allow aqueous to flow from the posterior chamber to the anterior chamber. Usually made with a laser.
Iris Pigmented tissue in front of the crystalline lens. Determines eye color. The central opening is the pupil, which allows light to reach the retina.
Iritis Inflammation of the iris. Associated with miosis (small pupil) and a red eye. Patient is frequently photophobic.
K Abbreviation for curvature of the cornea. The curvature is measured by a keratometer, e.g., K reading.
Keratectomy Surgical removal of any portion of the cornea.Keratitis An inflammation of the cornea. It may be caused by trauma as in an abrasion and surgery, infections by bacteria or viruses, or by immune disorders.
Keratoconjunctivitis An inflammation (infectious or autoimmune) of the cornea and conjunctiva.
Keratoconus An abnormality of the eye where the cornea becomes thin and deformed in the shape of a cone. This condition is usually a contraindication to excimer laser refractive surgery.Keratometer An instrument use to measure the curvature of the cornea.
Keratomileusis A refractive surgical technique where a partial thickness circular flap of cornea is removed, frozen, lathed to a new shape and replaced upon the cornea. The lathe can shape either a convex or concave lens.
Keratotomy Surgical incision of the cornea as in radial keratotomy.
LASEK An acronym for laser assisted subepithelial keratectomy. The epithelium is moved aside followed by excimer laser ablation of the cornea and replacement of the epithelium. A bandage contact lens in place on the cornea during the healing period.
Laser An acronym for light amplification by the stimulated emission of radiation. It is different from ordinary light and is millions of times more powerful than light energy produced by other sources. It is composed of one color (wavelength), and travels in one direction, and each light wave is traveling in step with the adjacent wave increasing the laser light energy.
Laser thermokeratoplasty A holmium laser is used to shrink the collagen fibers of the cornea and results in a “steeper” cornea. It is used for lower amount of hyperopia and does not require a creation of a flap.
LASIK An acronym for laser in situ keratomileusis. A surgical operation where a flap of surface cornea is cut and rolled aside followed by excimer laser ablation of the internal tissues (stroma or body) of the cornea to correct the refractive error. The flap is replaced and heals without sutures.
Lens A structure inside the eye that helps to focus light onto the retina. It also allows the eye to focus from distance to near. This is called accommodation. Presbyopia occurs when accommodation is lost starting around age 40. It is called a cataract when it becomes cloudy.
Lens capsule The elastic membrane enveloping the crystalline lens. This change the lens shape during accommodation to focus on near objects. It starts out clear and flexible and with age it first looses it flexibility (accommodation) and later clarity (cataract).
Lens cortex Softer lens material between the lens nucleus and lens capsule.
Lens nucleus Central area of the lens. This hardens with age.
Limbus The visible borderline between the clear window (cornea) and the white globe (sclera) of the eye. The conjunctival layer that covers the globe also joins at the limbus.
Limbal relaxing incision Incision made at the peripheral cornea to reduce astigmatism. A type of astigmatic keratotomy. It can be done at the time of or after cataract extraction.
Low contrast visual acuity - A measure of the sharpness of vision using a 10% low contrast chart with gray letters on a white background. Low contrast acuity testing is another way to determine how well patients can see in poor contrast conditions such as very dim light, rain, snow, and fog.
LRI Abbreviation for limbal relaxing incision.
LTK Abbreviation for laser thermokeratoplasty.
Lumigan Trade name for prostamide, used to treat glaucoma.
Macula Small central area of the retina surrounding the fovea. Area of responsible for sharp vision and color.
Macular degeneration Pathological conditions that result in loss of sharp central vision. Age-related macular degeneration (ARMD) is a leading cause of loss of central vision in seniors. There are two main groups, dry and wet. There are treatments for wet age-related macular degeneration.
Macular edema Swelling in the macular area caused by uveitis, retinal vascular diseases, and cataract surgery. It is usually temporary after cataract surgery but can be permanent in rare cases.
Meibomian gland dysfunction Abnormal composition of secretions from the meibomian glands on the eyelids. One cause of blepharitis.
Microkeratome A surgical instrument used in LASIK to cut a thin flap of tissue from the front surface of the eye before the laser treatment is applied.
Miochol Trade name for acetylcholine. A drug used to constrict the pupil at the end of cataract surgery. Duration of action is shorter than Miostat.
Miostat Trade name for carbachol, use to constrict the pupil at the end of cataract surgery. Longer duration of action compared to Miochol.
Mitomycin C An anti-cancer drug use to retard wound healing in eye surgery. Used to decrease the recurrence of ptergia. Also use to decrease haze in the cornea after surface ablation (PRK).
MFIOL Abbreviation for multifocal IOL.
Monovision One eye is set for distance vision and the other is set for near vision. Successful adaptation to monovision occurs in three to four weeks in about 80% of patients. The main advantage is not needing reading glasses for near tasks. The disadvantage is some decrease in depth perception. It has been our experience that patients in their 40s adapt to monovision in one to two weeks, and patients in their 60s may take a few months. If a patient does not have significant astigmatism, we have them try monovision with contact lenses. A few of the patients use glasses for night driving or for prolonged computer work or reading. Some monovision patients use one disposable contact lens in their near eye for good binocular vision during sports, such as tennis. Dr. Oyakawa had laser vision correction (PRK) with monovision. He uses prescription sunglasses for driving, no glasses for night driving, and glasses for prolonged computer work, reading, and close mechanical work. He is able to read the newspaper in the morning and function through out the day without glasses. During patient eye examinations and surgeries the eyepieces of the instruments are adjusted for binocularity.
Monofocal IOL A single-focus IOL. Usually set for distance. Glasses are usually needed. Does not correct for intermediate, near, or astigmatism.
Multifocal IOL As the name implies, an IOL that focus for many distances by splitting the light.
Mydriacyl Trade name for tropicamide. A drug used to dilate the pupil and paralyze accommodation. Routinely used for a complete eye examination to allow a good view of the lens and fundus.
Myopia A refractive abnormality of the eye requiring a minus (negative or concave) lens for correction. The layterm is nearsightedness. People who are nearsighted can see objects up close or at near without glasses.
Nearsightedness The layterm for myopia.
Neo-syneprine Trade name for phenylephrine. Routinely used with Mydriacyl to dilate the pupil.
Nidek Technologies Manufacturer of argon floride excimer laser machine EC-5000.
Nonproliferative diabetic retinopathy Early changes of diabetic retinopathy. Vision can be affected by macular edema or capillary loss.
Nonsteroidal antiinflammatory drug An antiinflammatory drug that does not contain steroids. Ibuprofen is a systemic NSAID use to treat generalized body pain. Ocular NSAIDS include Acular, Nevanac, and Xibrom. They are frequently used prior to and after cataract surgery to decrease the incidence of macular edema and after PRK to reduce pain.
NSAID Abbreviation for nonsteroidal antiinflammatory drug.
OCUFEN® Flurbiprofen sodium 0.03% Nonsteroidal antiinflammatory eyedrops used after PRK/LASEK to reduce pain. Also, used to control inflammation after cataract and other ocular surgery. Manufactured by Allergan.
Ocufloxacin A third-generation fluroquinones. Fourth-generation fluroquinones now in use.
Ocular hypertension Increased intraocular pressure. The intraocular pressure measures falsely low after excimer laser surgery due to the thinning of the cornea.
Off label use The permissible use of an approved drug or instrument in a way that has not been specifically sanctioned.
Ophthalmic Anything to do with the eye.
Ophthalmologist A medical doctor who specializes in the eye. To become an ophthalmologist, one must first obtain a medical degree (M.D.) followed by an internship and a residency in ophthalmology. A medical degree typically takes seven or eight years of university training, an internship takes one year and an ophthalmology residency takes three years. Fellowship training is another one to two years. Specialist MDs are usually divided into medical and surgical disciplines, and ophthalmology is technically a surgical discipline. Some ophthalmologists chose not to perform surgery and can be called medical ophthalmologist.
Optician An person who fits contact lens and glasses. They do not refract.
Optometrist (or Doctor of Optometry) is a healthcare provider who specializes in the examination, diagnosis, treatment, management and prevention of diseases, and disorders of the visual system, the eye and associated structures, as well as the diagnosis of related systemic conditions. Optometrists today most often complete a Bachelor of Science degree (with very specific requirements) followed by the four-year Optometry degree. Most optometrists include provision of contact lens and spectacle devices as part of their daily practice. They do not perform surgery. However, they can evaluate patients preoperative for the refractive and cataract surgeries and follow-up postoperatively.
Over-correction under-correction, and regression The desired correction was not achieved. This is due to many factors. Each person’s eye heals differently. The surgical plan is based on an average response to treatment. Some patients have an increased or decrease healing response. In addition the state of corneal hydration, the humidity and other unknown factors contribute to the response to surgery. These conditions can usually be enhanced (retreatment by lifting up the previously created flap and treating with the excimer laser) when stable. Enhancements are done three to six months after surgery when the eye is stable. It may take the eyes longer with sever correction to become stable.
Pachymetry Measurement of the thickness of the cornea. A minimum stromal thickness is necessary to prevent ectasia. Flap thickness and ablation depth determine the thickness of the stroma.
PCIOL Abbreviation for posterior chamber IOL.
PC-IOL Abbreviation for presbyopia correcting IOL.
Phacoemulsification The modern technique of cataract extraction through a very small incision (about 1/8 inch) using ultrasound to pulverize and remove the lens. An IOL is folded and inserted through very small incision. Recovery from surgery is very rapid without the postoperative restriction of older cataract techniques.
Phakic Having a natural lens.
Phakic Intraocular lens They are either placed in front of or behind the iris. They are usually used to correct severe refractive errors and maybe combined with excimer laser correction (Bioptics). There is an increased risk of complications compared to laser vision correction since this is an intraocular surgery.
Phakodonesis Lens movement with eye movement. This is caused by broken lens zonules.
Phoropter An optical instrument containing many lenses that is used to determine the power of glasses or refractive error.
Photoablation The cold process of tissue removal that occurs with laser in the 200 nm wavelength range. This far-UV wavelength possess light photons so powerful that the molecular bonds of the target tissue both break down and have sufficient extra kinetic energy to fly off the surface; hence ablation. Microscopic pictures show incredibly precise cuts with no evidence of tissue burning in adjacent tissue.
Photocoagulation The process of tissue destruction accomplished by visible light radiation. Tissue is broken down by the light and clots as if it were cooked.
Phototherapeutic keratectomy Excimer laser removal of surface tissue of the cornea such as scar tissue for medical or optical treatment reasons.
Photovaporization The process of tissue destruction as occurs with infrared light radiation such as with a Yag laser. The target tissue is ionized causing plasma formation followed by a shockwave.
Photorefractive keratectomy Excimer laser correction after the removal of the epithelium. A bandage contact lens is used during the healing period.
Pinguecula A yellowish spot seen on the white of the eye at the junction of the clear cornea and white sclera of the eye. These lesions are usually caused by UV radiation. The white surface of the eye cannot tan, and therefore cannot protect itself from sunburn.
Posterior capsule The posterior aspect of the capsule that surrounds the natural crystalline lens. Important to maintain its integrity during cataract surgery to allow implantation of the IOL in the capsular bag.
Posterior capsular rupture A surgical complication of cataract surgery when the posterior capsule is broken. Vitreous is frequently lost when this occurs. Vitreous loss is associated with an increase in postoperative complications such as CME, retinal detachment, IOL dislocation, acute bacterial endophthalmitis, etc.
Posterior capsulotomy To make an opening in the posterior capsule. It is usually done with a Yag laser when the posterior capsule opacifies decrease vision or causing glare. 10% to 30% of posterior capsule opacify after cataract surgery.
Posterior chamber The space between the iris and the vitreous.
Posterior chamber IOL An IOL behind the iris. A phakic IOL is in front of the natural lens. After cataract surgery PCIOLs are usually implanted into the capsular bag. However, at times it may be implanted into the sulcus is the capsular bag or zonules are compromised.
PRED FORTE® Prednisolone acetate 1% Corticosteroid eye drop used to reduce inflammation in excimer laser surgery, other ocular surgeries and ocular inflammation from other causes. It is used to decrease corneal haze and regulate healing response after PRK/LASEK. Manufactured by Allergan.
PRED MILD® Prednisolone acetate 0.12% Corticosteroid eye drop used to reduce inflammation in excimer laser surgery, other ocular surgeries and ocular inflammation from other causes. It is used to decrease corneal haze and regulate healing response after PRK/LASEK. Manufactured by Allergan.
Presbyopia Is a condition in which the ability to accommodate for near vision falls off because of loss of elasticity of the crystalline lens of the eye and weakness of the ciliary muscle. The individual is no longer able to read clearly and requires reading glasses. This usually starts in the early 40s.
Presbyopia correcting PC-IOL IOL that corrects for presbyopia. Refers to both multifocal and accommodating IOLs.
PRK Abbreviation for photorefractive keratectomy.
PTK Abbreviation for phototherapeutic keratectomy.
Pseudophakic Having an IOL.
Pterygium The growth of a pinguecula on to the cornea.
Ptosis Drooping of the upper eyelid.
Punctal plug Insertion of a plug into the puncta to prevent normal tear drainage. One of the treatments for dry eyes. There are two puncta per eye, an upper and lower. There are temporary plug that last two weeks or three months. These are used for the temporary treatment of dry eyes after LASIK, PRK, or corneal relaxing incision. Permanent silicone plug are also used.
Radial Pertaining to the radius or line from a circle center to the circle itself.
Radial keratotomy A surgical operation where 90% thickness cuts are made in the cornea. These cuts are made in a radial fashion and spare the visual center of the cornea. The intention is to flatten the central cornea and was used to treat myopia.
Refraction The bending of light wave as they pass from one medium to another also measurement of the lower order refractive error of the eye.
Regression Partial loss of refractive correction by refractive surgery such as LASIK, PRK, RK, LRIs, etc.
ReStor A diffractive multifocal IOL made by Alcon. It is mainly a bifocal IOL with excellent near vision and distance vision.
Retina The light sensitive layer that converts light images into electrical signals for transmission to the brain. Light must be focused correctly on the retina to form clear images. The retina can be compared to the film of a camera.
Retreatment See enhancement.
ReZoom A refractive multifocal IOL. Excellent distance with fair intermediate and good near.
RK Abbreviation for radial keratotomy.
Slit lamp A microscope for examining the eye.
Steroid medication A drug that reduces inflammation or the body’s reaction to injury, disease or surgery. Steroid eye drops are used after excimer laser correction. Inform your refractive surgeon if you are taking steroids.
Sulcus fixation The IOL is place in the sulcus (the space in front of the capsular bag) when the posterior capsule is damaged. See capsular bag, capsular fixation and anterior chamber IOL.
Sunrise syndrome An upward dislocation of an IOL.
Sunset syndrome A downward dislocation of an IOL.
Tear film A very thin film of water and other chemicals riding on top of the epithelium that lubricates the front of the eye.
Toric IOL An IOL that corrects astigmatism.
Topical proparacaine hydrochloride Anaesthetic eye drops.
Tonometer An instrument that measure the intraocular pressure.
UCVA Abbreviation for uncorrected visual acuity.
Uncorrected visual acuity This is the best vision measurement taken without the use of glasses or contact lenses.
Under correction Achieved correction is less than plan. Frequently a slight under correction is planned.
Viscoat Trade name for a viscoelastic agent combining chondroitin sulfate and sodium hyaluronate.
Viscoelastic agent A thick gel injected in the eye during cataract surgery to protect the endothelium and to maintain the anterior and posterior chambers during some of the surgical procedure.
Visual acuity A measure of the sharpness of vision using a Snellen Visual Acuity Chart.
Vitrectomy Removal of the vitreous from the eye. Anterior vitrectomy is the removal of the anterior part of the vitreous. This is usually done for the complication of vitreous loss during cataract surgery. It can be planned in certain type of anterior segment surgery. Pars plana vitrectomy is for removal of the posterior vitreous and retinal scar tissues. Most commonly done for complication of proliferative diabetic retinopathy, macular pucker, macular holes, etc.
Vitreous A clear gel that fills the eye between the lens and the retina.
Posterior vitreous detachment A separation of the vitreous gel from the retinal. Symptoms include flashes and floaters. This frequently occurs with aging or with pathological conditions such as diabetic retinopathy or high myopia. It can also occur from ocular trauma. The most serious complication of a posterior vitreous detachment is a retinal tear which can lead to a retinal detachment.
Vitreous floaters Opaque areas of the vitreous gel that casts shadows on the retina. A result of a posterior vitreous detachment or cause of vitreous opacification or syneresis.
VisX Manufacturer of argon floride excimer laser machines, VisX 2015, VisX 2020, and VisX STAR, VisxS3 and VisxS4.
Voltaren Ophthalmic Diclofenac sodium 0.1% nonsteroidal antiinflammatory eyedrops used after PRK/LASEK to reduce pain. Also, used to control inflammation after cataract and other ocular surgery.
Wavefront A measure of the total focusing errors (aberrations) including nearsightedness, astigmatism, and complex focusing errors (higher-order aberrations). Light is projected into your eye and focused on the retina. Part of this light is reflected back out of your eye to form the wavefront.
Wavelength The distance between the top of one wave and the top of the next wave. The argon fluoride excimer wavelength is 193 nm. This wavelength is in the far ultraviolet end of the electromagnetic spectrum.
Yag laser A laser type using an infra red wavelength of 1064 nanometers. The laser material is neodymium yttrium-aluminum-garnet. Yag lasers are used after cataract surgery to photovaporize the residual membrane behind the artificial lens.
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