Minimal, statistically insignificant changes in anterior curvature parameters are detectable in scleral contact lens wearers following removal after 6 hours of wear, according to research published in Cornea. However, these changes are transient and regress to baseline after overnight discontinuation of wear.
Researchers assessed 17 eyes of 12 patients (mean age 22.33±5.5 years, 8 men) with keratoconus. They recorded anterior flat (Kflat), anterior steep (Ksteep), and maximal keratometry (Kmax) measurements at baseline (45.03±7.25 D, 50.08±7.00 D, and 56.05±9.46 D, respectively) and performed pachymetry to assess central corneal thickness (CCT) (baseline CCT, 435.38±21.95 µm). They repeated measurements after 6 hours of lens wear and the next day after discontinuing use overnight.
The team found that the changes that took place after 6 hours of wear were transient and returned to baseline following the overnight period of discontinuation. Changes from baseline in Kflat (0.28±0.31 D, P =.37), Ksteep (0.37±0.09 D, P =.11), and Kmax (0.19±0.24 D, P =.53) were minimal and statistically insignificant, according to the study. CCT thickened by 7.76±3.00 µm and caused 1.77±0.67% of corneal edema after 6 hours. It too returned to baseline values after discontinuing overnight.
Overall, researchers noted no significant association between corneal flattening and change in corneal thickness (r=0.09, P =.78) or between central corneal clearance and change in corneal curvature (r=20.23, P =.51).
“Short-term scleral lens wear may cause marginal flattening in the anterior corneal curvature parameters and induce a minimal amount of corneal edema that regresse[s] to baseline after overnight cessation of the lens,” according to the investigators. “Corneal topography measurements for decision making on keratoconus progression should be performed after discontinuation of the lens for at least one overnight than immediately after lens removal in scleral lens wearers.”
Study limitations include a small sample size, short study duration, and lack of a control group.
Iqbal A, Mahadevan R. Impact of scleral lens on corneal curvature and pachymetry in keratoconic eyes. Cornea. 2022;41(5):579-582. doi:10.1097/ICO.0000000000002868.