[Corneal topography and pachymetry in normal eyes].
OBJECTIVE
To evaluate the corneal topography and pachymetry on normal eyes.


METHODS
The Orbscan corneal topography system was used to investigate corneal topography and pachymetry on 46 normal subjects.


RESULTS
In normal eyes, island-shape was the most common type in the elevation topography of anterior corneal surface, followed by incomplete ridge, regular ridge, irregular ridge and unclassified type. For the elevation topography of posterior corneal surface, the most common type was also the island-shape, followed by regular ridge, incomplete ridge and irregular ridge. The thinnest point of cornea in normal eyes was located (0.90 plus minus 0.51) mm away from the visual axis with the thickness of (0.55 plus minus 0.33) mm, which was commonly seen at the inferotemporal quarter of cornea, followed by superotemporal, inferonasal and superonasal quarter. The mean corneal thickness was the least in corneal center and greatest in superior part of cornea. For the color-coded map of corneal thickness, oval shape was the commonest type, followed by round shape, eccentric oval shape and eccentric round shape.


CONCLUSIONS
The normal parameters on pan-corneal thickness and corneal shape of both anterior and posterior surface will provide much more useful informations in finding abnormal cornea. Orbscan topography system is a useful instrument for the evaluation of corneal shape and thickness, which is helpful in corneal refractive surgeries.
Liu
Z
Z
Zhongshan Ophthalmic Center, Sun Yat-sen University of Medical Sciences, Guangzhou 510060, China.
Xie
Y
Y
Zhang
M
M
D000328:Adult; D000368:Aged; D003315:Cornea / Q000033:anatomy & histology* / Q000502:physiology; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009885:Ophthalmology / Q000379:methods*; D012029:Refraction, Ocular