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What is it? |
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Keratometry is a technique used for the measurement of anterior corneal curvature of the eye with the help of keratometer. |
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What is it done for?
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It is primarily done to diagnose the presence of astigmatism and to determine the degree and treatment of astigmatism.
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How is it done?
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It is done by measuring the size of an image reflected from two paracentral points on the cornea. The instrument contains doubling prism to stabilize the image allowing more accurate focusing .The anterior corneal curvature is then obtained from the convex mirror formula and corneal power is calculated. |
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What are the benefits?
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Used for measuring anterior corneal curvature to find out cylindrical value of the eye. Used prior to different eye surgeries, cataract,l asik and corneal surgeries. Used in contact lens fitting. |
5-What are the limitations?
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Keratometry assumes that the corneal surface is spherocylindrical and therefore it does not measure accurately if the surface is not truly spherocylindrical..It does not quantify irregular astigmatism.It does not provide information regarding the paracentral and peripheral surfaces. It does not detect early keratoconus as the changes are limited to posterior corneal surfaces. |
6- How much time is taken?
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The time taken for both eyes is 5 to 10 minutes. |
| When is to be repeated? |
| As per doctors advise. |
| What are other alternative tests? |
| Corneal topography test. |
| How much does it cost? |
The cost may vary from one hospital to the other.
Dr. Sanjay
Dhawan, New Delhi, India.
Updated on 13 May 2011 |
