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John David Gelles, Daniel Chung, Steven Greenstein, Becky Su, Jenny Nguyen, Amrit Singh, Peter Hersh; Correlation of Scleral Lens Parameters with Scheimpflug Tomography Metrics. Invest. Ophthalmol. Vis. Sci. 2022;63(7):547 – A0245.
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© ARVO (1962-2015); The Authors (2016-present)
To examine the relationship between base curve (BC) and sagittal depth (Sag) of scleral lenses (SL) with various tomography metrics in patients successfully fit with SL.
A retrospective chart review of patients successfully fit with SL (Zenlens, 16mm and 17mm, Bausch + Lomb SVP, Lancaster, NY and CustomStable, 17.8 and 16.8mm, Valley Contax, Springfield, OR) was performed. 76 eyes of 44 patients were included in the study. The average age was 45.92 ± 12.31. Of the 76 eyes, 74 were fit for irregular corneal conditions and 2 were fit for ocular surface disease. Final prescribed SL parameters, BC and Sag, and scheimpflug tomography (Pentacam HR, Oculus, Germany) metrics, including maximum keratometry (Kmax), mean keratometry (Kmean), flat keratometry (Kflat), steep keratometry (Ksteep), anterior chamber depth (ACD), white-to-white horizontal corneal diameter (WTW), and the inferior-superior (IS) ratio at the 6 mm zone, were obtained. To account for differences in labeled Sag between the SL designs, the lowest lens Sag was subtracted from the other lenses in their respective SL design cohort. The difference in µ was then consistent across SL designs for direct comparison. Statistical analysis for correlation of tomography metrics and final SL parameters was performed (SPSS, IBM Corporation, Armonk, NY).
A positive correlation was found between the final prescribed Sag and ACD (R=0.70, p<.001), Kmax (R=0.61, p<.001), Kmean (R=0.54, p<.001), Kflat (R=0.45, p<.001), Ksteep (R=0.59, p<.001), and IS ratio (R=0.25, P=.03). No correlation was found between Sag and WTW (R=0.08, p=.5). No correlation was found between BC and ACD (R=0.14, p=.24), Kmax (R=0.11, p=.34), Kmean (R=0.12, p=.29), Kflat (R=0.06, p=.61), Ksteep (R= 0.1, p=.39), IS ratio (R=0.18, p=.12), or WTW (R=0.04, p=.73).
Of the tomographic metrics analyzed, ACD was most strongly correlated with SL Sag followed by a correlation with Ksteep and Kmax. Tomographic metrics were not correlated with SL BC, indicating BC is an independent variable. This data suggests ACD may be the best metric to aid in selecting diagnostic SL during the SL fitting process.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.
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