Corneal and Scleral Elevation Topography Changes After Corneal Hydrops in Keratoconus Cases
Gregory DeNaeyer OD, Donald R. Sanders MD, PhD, Timothy S. Farajian
A recent case was reported where collagen crosslinking not only substantially changed the cornea but also the scleral shape necessitating a remake to the previously well-fitting scleral lens. It was unclear whether this scleral shape change occurred directly because of selective areas of stiffening of the sclera based upon riboflavin accumulation and UV light exposure or indirectly due to transmitted stress or tightening from the cornea. Consejo and Rozema have argued against an indirect effect since the stiffness of the sclera is higher than the cornea making it more difficult for the cornea to deform the sclera. DeNaeyer G, Sanders DR van der Worp, E, et.al. described the use of circumferential scleral plots (Figure 1) to characterize scleral surface patterns. These plots can be generated for any radius from the corneal center and thus can be used to compare corneal and scleral changes after hydrops or other pathology or procedures affecting ocular surface shape. This report summarizes 4 cases of corneal hydrops where Corneo-scleral topography using the sMap3D™ instrument (Precision Ocular Metrology, Los Angeles, CA) was performed prior to and 3-5 months post the hydrops event. Since hydrops only affects the cornea, any effect on the scleral should be indirect due to corneal changes.
Drs. DeNaeyer and Sanders and Mr. Farajian are shareholders in Precision Ocular Metrology, the manufacturer of the sMap3D™ instrument. Dr. Sanders is a shareholder of and Dr. DeNaeyer is a consultant to Visionary Optics, distributor of the sMap3D™ and manufacturer of the Europa Scleral lens.