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William Leonard Miller, Kelsea Vance, Leah Johnson, Jan P G Bergmanson; Scleral Contact Lens Effects on Central and Peripheral Corneal Thickness.. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):6103.
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© ARVO (1962-2015); The Authors (2016-present)
Scleral contact lenses are an essential mode of correcting corneal abnormalities as a result of keratconus and corneal surgery. New generations of lenses have focused on design features that allow vaulting the irregular corneal surface and navigating limbal and scleral anatomy. Recently, research has addressed the theoretical physiological requirements needed for oxygen transmissability that takes into account Dk/t of scleral lens and tear film. The purpose of the present study was to determine the effect of scleral contact lenses on corneal physiology.
Corneal thickness of 24 eyes of 16 patients seen in a scleral lens predominant practice in the TERTC of the University of Houston were analyzed. Each patient had been wearing the scleral contact lens for at least 2 weeks. Each scleral lens prescribed was shown to have an acceptable fit by the contact lens practitioner with no areas of impingement or conjunctival blanching. The age range from 26 to 70 years of age with 10 males and 6 females included for analysis. The corneal thickness of the central, peripheral and apical regions were measured before being fitted with scleral contact lenses with a Pentacam tomographer.
The mean pupillary corneal thickness pre-lens wear was 502+/- 9.3 microns and after lens wear was 507+/- 8.8 microns. Apical corneal thickness before and after lens wear was 485+/- 11.2 and 484+/- 12.5 microns respectively. The inferior corneal thickness was 638+/- 27.7 and 643+/-18.0 microns before and after scleral lens wear. Corneal thickenss in the superior region of the cornea was 640+/- 9.4 and 658+/- 9.7 microns before and after scleral lens wear. Corneal volume was 57 prior to lens wear and 59 after lens wear.
Results indicated that the central, apical and inferior peripheral corneal thickness were not statistically different before and after scleral contact lens wear. The superior corneal thickness was increased but was not statistically significant. This clinical study showed no significant corneal swelling in a small group of patients satisfactorily fitted in a scleral contact lens. Assuming an adequate fitting and without excessive corneal vault, scleral lenses do not appear to cause significant corneal swelling. Other factors not observed in this patient population such as low endothelial cell density and poor tear exchange may induce corneal swelling.
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