Observation Of A Large Sample，Influence Of Corneal Diameter On Belin/Ambrόsio Enhanced Ectasia Display Deviation Indices By Pentacam

To evaluate the influence of corneal diameter on Belin/Ambrόsio Enhanced Ectasia Display (BAD) deviation indices in Han Chinese with myopia.

Baiji Chongqing Ophthalmology Hospital, Chongqing, China 400042

In this cross-sectional clinical study, 6744 individual eyes randomly selected from 6744 patients were studied using Pentacam HR by acquiring HWTW and BAD-D. Subjects were divided into 3 groups by HWTW：Group-A(HWTW<11.2mm), Group-B(HWTW: 11.2 to 11.8 mm), Group-C(HWTW>11.8mm). The outcome measures were deviation of front elevation difference(Df), deviation of back elevation difference(Db), deviation of average pachymetric progression(Dp), deviation of minimum thickness(Dt), deviation of Ambrosio relational thickness maximum(Da) and total deviation value(D) . SPSS 25.0 was used for statistical analysis. BAD-D were compared with single factor analysis of variance. Chi-square test assessed differences in groups for each variable. 

There were 630 eyes (9.34%) in Group A, 4063 eyes (60.25%) in Group B and 2051 eyes (30.41%) in Group C. Statistically significant differences were noted between the groups for all parameters except for corneal thickness in single factor analysis(p <0.05). The proportion of abnormal values in Db, Dp, Da, and D value from Goup A (small cornea group) were higher than those in other groups (p <0.05). 

There are individual differences in corneal diameter of the same race, and corneal diameter has a significant effect on Belin/Ambrόsio Enhanced Ectasia Display. The false-positive results of Belin/Ambrόsio Enhanced Ectasia Display are higher in small cornea patients than that in large cornea patients. Considering cornea diameter is necessary when we evaluate corneal ectasia risk for keratorefractive surgery candidates with myopia using BAD.