Refractive Surgery Terms

20/20 Vision

Normal visual acuity (clarity); what the average person sees at 20 feet.

Best Corrected Visual Acuity (BCVA)

The best vision a person can achieve with glasses or contact lenses.

Cylinder

Part of a prescription that corrects astigmatism.

Diopter

A unit of measurement for the optical power of a lens.

Fluctuation

Temporary changes in vision often seen during healing after surgery.

IOPs (Intraocular Pressures)

Fluid pressure inside the eye; important in glaucoma screening.

Keratometry (K Readings)

Measurement of the curvature of the cornea.

Pachymetry

Measurement of corneal thickness; important for LASIK/PRK candidacy.

Peripheral Vision

Ability to see to the sides when looking straight ahead.

Refraction

Test to determine a person's glasses or contact lens prescription.

Sphere

The part of a prescription that indicates nearsightedness or farsightedness.

Visual Acuity

How clearly a person sees, typically expressed as 20/20, 20/40, etc.

Cornea

Clear front surface of the eye that is reshaped in refractive surgery.

Epithelium

Thin outer layer of the cornea; regenerates after PRK.

Retina

Light-sensitive tissue lining the back of the eye; crucial for vision.

Stroma

Middle layer of the cornea where reshaping occurs in LASIK/PRK.

Ablation

Removal of corneal tissue using a laser to reshape the eye.

Bandage Contact Lens (BCL)

Soft lens used post-operatively to protect the eye and promote healing.

DLK (Diffuse Lamellar Keratitis)

Rare inflammatory condition under LASIK flap.

Enhancement

Follow-up procedure to improve vision after initial surgery.

Epi Cell Removal

Removal of epithelial cells during PRK or PTK procedures.

Excimer Laser

Laser used to reshape the cornea in LASIK and PRK.

FDA

Regulatory agency that approves eye surgery devices and procedures.

Glare

Visual distortion from bright lights, often post-surgery.

Halos

Rings around lights seen after surgery, especially at night.

Haze

Temporary corneal cloudiness after PRK.

Monovision

Correcting one eye for distance and the other for near vision.

Photo Refractive Keratectomy (PRK)

Laser reshaping of the cornea without creating a flap.

Photo Therapeutic Keratectomy (PTK)

Laser treatment for corneal disease or scarring.

Radial Keratotomy (RK)

Outdated procedure using radial cuts in the cornea to correct myopia.

Refractive Lens Exchange (RLE)

Replacement of the eye's natural lens with an artificial one to correct vision.

Refractive Surgery

Any surgery to reduce or eliminate the need for glasses or contacts.

Astigmatism

Irregular curvature of the cornea or lens causing distorted vision.

Cataract

Clouding of the eye's natural lens.

Contradiction (Contraindication)

A reason not to perform a procedure or treatment.

Hyperopia

Farsightedness; near objects appear blurry.

Myopia

Nearsightedness; distant objects appear blurry.

Presbyopia

Age-related loss of ability to focus on near objects.

Regression

Return toward the original prescription after refractive surgery.