PURPOSE: To evaluate the prevalence of different topographic patterns in refractive surgery candidates and to estimate the extent of candidate rejection based on topography alone. METHODS: We performed a retrospective evaluation of videokeratographies of previously unoperated refractive surgery candidates. The defined topographic patterns of their corneas and the indices computed by the videokeratographer software were registered. The data were evaluated by SPSS/PC statistical software. RESULTS: One hundred candidate electronic topography records were evaluated. The candidates included 41 women and 59 men whose average age was 32 years (range 17.5-63.5). Their topographic patterns were: spherical (36/200 evaluated eyes), spherocylindrical (60), upper steep (32), lower steep (43), irregular astigmatism (9), decentered (3), suspected keratoconus (11), and probable keratoconus (6 eyes). Rejection from undergoing the procedure was based on topography alone in 27 of the 200 eyes. It was difficult to decide what to do with the 43 eyes with a lower steep pattern, and they were eventually rejected. Of the nine software-calculated indices, only one, "keratoconus index," could distinguish between the spherocylindrical and the lower steep patterns. CONCLUSIONS: More than one-half of corneal topographies of refractive surgery candidates did not comply with the assumed "normal" spherical or spherocylindrical patterns. The possible continuum of keratoconus-suspected keratoconus-lower steep pattern raises the question of where to draw the line between reasonable and risky when considering corneal refractive surgery.
PURPOSE: To evaluate the prevalence of different topographic patterns in refractive surgery candidates and to estimate the extent of candidate rejection based on topography alone. METHODS: We performed a retrospective evaluation of videokeratographies of previously unoperated refractive surgery candidates. The defined topographic patterns of their corneas and the indices computed by the videokeratographer software were registered. The data were evaluated by SPSS/PC statistical software. RESULTS: One hundred candidate electronic topography records were evaluated. The candidates included 41 women and 59 men whose average age was 32 years (range 17.5-63.5). Their topographic patterns were: spherical (36/200 evaluated eyes), spherocylindrical (60), upper steep (32), lower steep (43), irregular astigmatism (9), decentered (3), suspected keratoconus (11), and probable keratoconus (6 eyes). Rejection from undergoing the procedure was based on topography alone in 27 of the 200 eyes. It was difficult to decide what to do with the 43 eyes with a lower steep pattern, and they were eventually rejected. Of the nine software-calculated indices, only one, "keratoconus index," could distinguish between the spherocylindrical and the lower steep patterns. CONCLUSIONS: More than one-half of corneal topographies of refractive surgery candidates did not comply with the assumed "normal" spherical or spherocylindrical patterns. The possible continuum of keratoconus-suspected keratoconus-lower steep pattern raises the question of where to draw the line between reasonable and risky when considering corneal refractive surgery.
Authors: Sepehr Feizi; Siamak Delfazayebaher; Mohammad Ali Javadi; Farid Karimian; Vahid Ownagh; Fatemeh Sadeghpour Journal: J Ophthalmic Vis Res Date: 2018 Apr-Jun