A Study on Central Corneal Pachymetry Maps with Orbscan Corneal Pachymetry System in Myopic Eyes

Purpose : To evaluate central corneal thickness and pachymetry maps in myopic eyes. Methods : 104 eyes of 52 myopic patients were investigated using the Orbscan (Orbtek, Inc., USA). The pachymetry maps were designated as round, oval, decentred round, and decentred oval. Corneal thickness was evaluated at the central, eight-paracentral, and the thinnest sites on each of the corneas. We studied difference of corneal thickness under sex and myopic degree. And got the symmetry of the cornea under location of the thinnest sites. Results : Superior cornea had the greatest average thickness (605.535.3 ). Average central corneal thickness (SD) was 552.2 (34.9) . All corneas had the thinnest sites on 0.86 mm from the visual axis and most of all inferotemporal area (76.0%). There was no significant difference of corneal thickness in sex and myopic degree. Average thickness of the thinnest sites was 544.2 (35.6) and significantly thinner than center. 61.5% of the persons had symmetrically located thinnest corneal sites and most of all (57.7%) had temporal side symmetry. In the pachymetry maps, oval pattern was 47.1% of 104 eyes, and round, decentred oval, decentred round were observed in 43.3%, 5.8%, and 3.8% of eyes, respectively. Conclusions : Of all myopic eyes evaluated in this study, the thinnest sites were on average 0.86 mm from the visual axis. And oval type was the most common pachymetry map pattern.