Eye+Examination+Tools

=toc Eye Examination Tools=

What are they used for?
Eye examinations are performed with numerous and a variety of different pieces equipment. These procedures help determine and find abnormalities in the eye and how well the person can see. They are performed by an Ophthalmologist or an optometrist. Not only can abnormalities or diseases be found during these exams but also, can determine whether a person has low or high blood pressure or is diabetic (systematic diseases). They can do this because blood vessels on the retina are observed during examinations. Examinations should be performed every two to three years, and early eye exams on children are very important because early decreases in vision can occur such as a "lazy eye".

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A preview of what occurs during an eye exam

How is light used in eye tools?
Light is used in different ways to show different parts of the eye clearly and to look for any abnormalities and problems. Using light is best because your eye reacts to light in a specific way in different areas.

Parts of the eye.

Manual Keratometer:
A manual Keratometer uses corneal reflections (the cornea acts as a convex mirror reflecting light) to observe whether the cornea is flat or steep compared to the average person's eye. It is used to diagnose various conditions such as astigmatism, corneal scarring and distortion.

A ray diagram demonstrating how it works.

Corneal topography:
An instrument that sends a series of rings into the corneal surface that reflect back into the instrument. They are analyzed by a computer and a topography map. It is similar to the keratometer, showing the shape of the cornea more precisely. This tool also helps perform laser vision correction.



The rings are used to measure the curvature of the eye.

media type="youtube" key="Ck0iyKShTsA" height="315" width="420" A basic view of corneal Topography