Removal of corneal tissue carried out surgically. The word is derived from the Latin word ‘ablation’ meaning to ‘carry away’.


Acuity refers to the sharpness or clarity of your vision.


An eye condition where the eye does not focus light uniformly in all directions resulting from an irregular curvature of the cornea. The cornea has the shape of a rugby ball rather than a soccer ball. It results in blurred vision.


This is the transparent dome-shaped front portion of the outer covering of the eye; it covers the iris and pupil and is continuous with the sclera.

Corneal Epithelium

The epithelium is the thin, protective layer of cells covering the cornea.

Corneal Thickness

The corneal thickness is a very important measurement in corneal surgical procedures. It determines how much tissue can be removed without creating an unstable cornea. This measurement automatically defined the limits for the procedure. The normal human cornea varies from around 500 to 600 micrometers in thickness.

Corneal Topography

A non-invasive medical imaging technique for mapping the surface curvature of the cornea. Since the cornea is normally responsible for approximately 70% of the eye’s refractive power, its topography is of critical importance in determining the quality of vision.


A unit of measurement used to describe the degree of refractive error with respect to near-sightedness, far-sightedness and astigmatism.


This is a condition in which the cornea bulges or becomes more conical in shape due to structural change or weakness of the cornea. This results in increasing short-sightedness and astigmatism.

Excimer Laser

An excimer laser refers to the type of laser used in refractive surgery. Excimer lasers use cool beams of ultraviolet light to evaporate corneal tissue during vision correction.


This is a retreatment procedure that may be required after LASIK or PRK if your prescription is not corrected adequately.

Far-sightedness: Far-sightedness is another name for Hyperopia or Hypermetropia. Your distance vision will be better than your close vision.


Far-sightedness is another name for Hyperopia or Hypermetropia. Your distance vision will be better than your close vision.


The iris is the coloured portion of the eye and it is made up of muscle tissue. The centre of the iris is an opening called the pupil.


Keratos is the Greek word for cornea, and ectomy means to remove. Together they mean to remove corneal tissue.


Keratos is the Greek word for cornea, and mileusis means to reshape. Together they mean to reshape the cornea.


This is an infection or inflammation of the cornea.


LASIK is an acronym for “laser assisted in situ keratomileusis.” This is more simply said as “reshaping the cornea using a laser.”


The lens is located behind the pupil and is it like a tiny magnifying glass that focuses light rays onto the retina.


A sophisticated instrument used to create a corneal flap during LASIK surgery.


When one eye is deliberately corrected for distance vision and the other for close vision.


Also called shortsightedness / near sightedness. Myopic people typically have difficulty seeing objects at a distance.

Ophthalmologist or Ophthalmic Surgeon

Is a medical doctor specializing in the diagnosis and treatment of all conditions involving the eye. This includes eye surgery and laser treatment.


Is a person trained to examine eyes for defects of vision and disease and to prescribe and dispense corrective spectacles or contact lenses.


“Presbys” is Greek for “old man” and “opia” refers to the eye. Presbyopia typically occurs in patients over 40 years of age, and it makes reading things up close difficult. It occurs because our lens loses its ability to accommodate, or change shape.


The pupil is the dark opening in the centre of the iris. It regulates the amount of light entering the eye.

Refractive Error

These are imperfections in the focusing power of the eye, so that light rays are not brought into sharp focus on the retina, causing blurred vision that can usually be corrected with glasses or contact lenses. Near-sightedness (myopia), far-sightedness (hyperopia), and astigmatism are refractive errors.


This is the innermost light-sensitive membrane covering the back wall of the eye; it is continuous with the optic nerve, which transmits information to the brain.

Snellen Chart

The familiar eye chart with larger letters at the top and smaller ones at the bottom. Used for measuring central vision.