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A - Z of Eyes & Focusing
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
P
Pachymetry
The process of measuring corneal thickness, usually using the Oculus Pentacam or an ultrasonic probe. The Pentacam measures corneal thickness in thousands of points in your cornea.
Pentacam
A precision diagnostic tool that gives detailed information about the front part of the eye, including thickness of the cornea, shape of the front and back of the cornea, depth of the anterior chamber of the eye (between cornea and lens) and density of any cataract in the eye.
Photorefractive keratotomy
A procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma. Acronym is PRK.
Plano
Characterized by no refractive error.
Practice of medicine
A regulatory body's allowance of practitioners to make decisions to best serve their patients.
Presbyopia
The natural deterioration of near vision caused by loss of flexibility in the eye's lens as one ages.
PRK
The acronym for photorefractive keratotomy. A procedure involving the removal of the surface layer of the cornea (epithelium) by gentle scraping and use of a computer-controlled excimer laser to reshape the stroma.
Ptosis
Droopy eyelid.
Q
No entries.
R
Radial keratotomy (RK)
A surgical procedure designed to correct myopia (nearsightedness) by flattening the cornea with incisions. The procedure is called a radial keratotomy because the incisions resemble the spokes in a wheel. This was used before the excimer laser became available, and is no longer used now.
Refraction
The bending of light waves as they pass from one medium to another (such as from air to water).
Refractive surgery
Any surgical procedure that attempts to decrease the patient's refractive error. Typically the surgeon alters the shape of the cornea in order to change the angle at which an image is projected onto the retina.
Regression
A backwards shift from the initial visual outcome.
Regular astigmatism
A refractive error caused by an irregular shape of the cornea (usually a rugby ball shape) in which the curvature is symmetrical across one or more meridians or axes. The steep curve and the flat curve are at 90 degrees from each other, as in the shape of a rugby ball.
Retina
Light processing membrane; converts light into electrical impulses that are transmitted to the optic nerve.
