Vision Glossary

20/20 A measurement in the vision community that states perfect vision. The measurement is a fraction and the first number is a description of the distance the patient was standing from the chart and still able to read the letters. The second number of the fraction states the distance from which a person with 20/20 sight would see the numbers. It is somewhat of a comparison to see where the patient stands.

AccommodationThe eye’s ability to focus on objects which are closer or further away. When this focusing ability works correctly the eye is able to clearly identify all objects. With age or poor vision, this ability to focus (accommodate) is weakened and does not work correctly.

Acuity The clarity of a patients eyesight.

After Image When the patient sees an image after they blink and the image is removed. For example, when someone takes a picture with a flash camera and they are still able to see the light after the picture has been taken.

AK A surgery where the surgeon will slice and reform the cornea so that once it heals, the patient will have better vision and it reduces the symptoms of an astigmatism.

Amblyopia A condition otherwise know as “lazy eye”. The quality of vision is reduced, most likely glasses will be needed due to the blurring effects.

Aniseikona A disorder where the patients visualize one object as two different sizes.

Anisometropia A common condition where the two eyes posses different refractive powers. This can be easily fixed with two different strength prescriptions in glasses, contacts or lasik eye surgery.

Anterior Chamber Eye ball part which is set behind the cornea but in front of the lens and iris.

Arcus A ring around the cornea. It is composed of excess fatty tissues and deposits.

Asthenopia When the eye continues tearing, redness, dryness and experiencing pain. Many times it is from eye strain and relaxation techniques can help.

Astigmatism A common condition which can be repaired during a lasik procedure or with toric lenses. This condition is characterized by distorted vision and difficulty wearing normal contact lenses. The eye ball is usually shaped like football and irregular in size.

Band Keratopathy A disorder where a band of deposits are in between the stroma and browmans’s membrane. Band Keratopathy is characterized deteriorated vision and strange body sensations.

Bifocal A type of lens which allows the patient to see far distances, as well as close up distances without any interference. Not available in lasik procedures yet. However they are available with contacts and glasses.

Blurred Vision Weak or distorted vision, can be corrected with lasik eye surgery, contacts or glasses.

Bowman’s Membrane Tissue layer between the stroma and epithelium.

Central Island A type of refractive lasik surgery where the laser creates an island in the cornea. This is a mistake made by the doctor and will lead to blurry vision and uncomfortable side effects.

ChoroidsBlood vessels in the surface of the whites of the eyes. They nourish the eyes and keep a constant flow of oxygen and nutrients.

Ciliary Body Tissues behind the eye, which keep it secured and in place.

Conductive Keratoplasty (CK) A type of lasik procedure where heated waves are sent to the cornea in order to shrink it and repair farsightedness.

CPT A color perception test which tests the patients ability to view colors.

Computer Vision Syndrome Vision issues caused by long hours of computer working. Symptoms usually include burning, itching, reduced vision quality and red eyes. Muscle strains in the neck and shoulder areas and headaches.

Cone A receptor in the eye which is capable of viewing images and color.

Convergence When the patients eyes are able to move inwards. This assists in the focusing close proximity objects.

Corneal Abbrasion A condition where the top layer of the cornea is scratched or damaged. This can be caused by major or minor trauma. Lasik surgery can not be completed until the cornea is completely healed and this may take some time.

Decentered Ablation Also known as decentration. This complication during the refractive surgery where the laser does not center on the pupil and the patient experiences glares, halos and double vision. This condition is especially active at night.

Diplopia Clinical term for double vision. Lasik surgery may or may not be able to repair this disorder.

Divergence This is the act of using both eyes to focus on an object in the distance.

Dry Eye Syndrome Continual dryness of the eyes and inability to produce a constant stream of tears. This is a very uncomfortable condition, but can be treated with eye drops and other medical treatments.

Edema A condition of the eye where excessive fluid fills they eye and it constantly tears. Edema can also cause swelling.

Emmetropia Perfect 20/20 vision, no need for glasses, contacts or any other vision correction.

Endopthalmitis An irritation in the eye caused by a surgical procedure, like lasik. The symptoms include swelling, redness, burning, light sensitivity and more. This irritation can be treated easily, but may take some time to heal.

Endothelium An inner layer of cells inside the cornea.

Epithelial Ingrowth A lasik surgery complication where damaging cells grow underneath the lasik flap. An infection can occur and cause pain and damage.

Eye Track A testing measurement of the eyes movement electronically.

Facility of Accommodation The measurement of an eyes ability to focus within a given amount of time.

Farsightedness Also known as hyperopia. This means the objects which are close seems blurry and these patients are unable to focus.

Flap and Zap Slang for Lasik eye surgery.

Higher Order Abbreviation Any inconsistency or irregularity of the eye. This includes far sightedness, nearsightedness or both. These irregularities can be fixed with lasik surgery, glasses or contacts.

Hyperopia Another term for nearsightedness. The eyeball is misshapen and short in length. Objects which are close up are blurry. This condition can be corrected with lasik, glasses or contacts.

Iris A colored membrane which is set between the lens and cornea. It controls the pupil and allows the correct amount of light into the eye, so that vision is comfortable.

Keratoplasty Another type of lasik or corneal surgery which will cut down on nearsightedness and hopefully improve the patients vision.

Keratomy An incision on the cornea.

Lensometer Also known as a Verometer. This measurement helps to measure the refractive power of the eye.

Low Vision Half vision, which can not be corrected by contacts, glasses or lasik.

Macula A very fragile and sensitive part of the retina.

Microcornea An unusually small cornea.

Microkeratome A surgical instrument used to extract the cornea.

Myopia Another term for nearsightedness. Patients with this condition experience poor night vision, blurry vision and many other problems. It is not serious, however the patient may need lasik surgery, contacts or glasses.

Nearsightedness Another term for myopia. Images in the distance seem further away than they really are and are very blurry.

Ophthalmologist A certified medical doctor who specializes in the eyes and vision. They can write prescriptions, order glasses and perform examinations.

Optic Nerve Nerve fibers which are bundled up behind the eyeball. This never connects the eyes and images to the brain.

PRK A type of laser which is used in a surgical manner to improve eyesight.

Pupil The dark, almost black, center part of the eye. This part of the eye adjusts to the amount of light in any given are, so that the human may see clearer.

Refractive Error When the eye is not correctly shaped to be able to filter light beams correctly. Images will appear blurry and some sort of correction is necessary. Patients may be nearsighted, farsightedness or suffer from astigmatism.

Refractive Surgery Surgery which repairs any refractive errors. After the procedure the patient will no longer need to use glasses, contacts or any other vision correction device.

Retina Layer of tissue in the back of the eye which is sensitive to light. Impulses are sent to the brain to decipher the image and its color composition.

Sclera The outer coating and layer on the cornea, it is the protection for the eyeball.

RK The abbreviation for Radial Keratotomy. This is a procedure where slices are made in a radial pattern on the eye to improve vision. This surgery flattens the cornea and corrects other conditions.

Stroma The middle layer of the cornea. It is comprised of cells and other materials, organs, tissues and nerves.

Uvea A middle layer of tissue in the eye. This area can become easily infected.

Vitreous Area of fluid in front of the retina, behind the lens.

Wavefront A type of lasik technology where the laser take a map image of the eye and corrects vision.