Corneal thickness & Intraocular Pressure (IOP) David Kinshuck |
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Why is this relevant? |
| We now know that corneal thickness infuences IOP.
There is a graph of the relationship, modified from Ko
here.
Thus if your conrea is very thin (say 400um), your pressure may read 10mmHg. But the real or equivalent pressure (for the average eyeof 560um) would be 16mmHg. So the presure in an eye with a thin cornea reads to low...the real pressure is higher. Similarly if you have Fuchs corneal dystrophy with a thick cornea, perhaps 640um, the pressure may be 18mmHg...equivalent to 15 for a 560 (normal) cornea. Goldmann tonometry is least influenced by thickness, air tonometry the most, blood flow tonometry in between. |
Other references |
| See here. Corneal curvature also influences pressure measurement. |
| The address of this site ('org' changing to 'nhs') is changing from http://www.goodhope.org.uk/departments/eyedept/ to http://www.goodhope.nhs.uk/departments/eyedept/ |
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