[The differences in corneal shape between myopic and normal eyes].

The corneal shapes of 35 eyes with moderate and mild degrees of myopia compared with those of 35 normal eyes were studied by a computerized video keratoscope (TMS-1). The results show that the surface regularity index (SRI), the refractive power at central optical zone, the simulated keratoscopic reading (Simk), the average corneal power of zones 3mm, 5mm, 7mm in diameter centered at the corneal center of the eyes with moderate and mild degrees of myopia are greater than those of the normal eyes (P < 0.05). However, the surface asymmetry index (SAI), the differences of corneal powers between the first and the 15th ring and between the first and the 25th ring in both groups are of no statistical significant differences (P > 0.05). It is suggested that the corneal refractive power of myopic eye be much higher than that of the normal eye. The authors propose the first time that the pathogenesis of some eyes with moderate and mild myopia may be the increase of corneal refractive power which results from traction of sclera near the limbus due to accommodation and discuss it in detail.