No Subclinical Effect Seen on Cornea After 3 Months Scleral Lenses Wear

Contact lens designs are classified as scleral lenses when there is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral and large-scleral lenses. These distinctions emphasize differences in central corneal clearance and other fitting characteristics. A lens that is 6mm larger than the visible iris diameter is classified as a mini-scleral lens.
Researchers evaluated the subclinical corneas of scleral lens wearers after 3 months.

After 3 months of full-time scleral lens wear, with no overnight use, a cohort of 27 young adult neophyte scleral lens wearers showed no significant subclinical effect on the cornea.1 As a secondary finding, the study shows that buffered and nonbuffered saline solutions impacted the corneal health of these patients in similar ways.1

The study used fluorometry and in vivo confocal microscopy to evaluate the effects of scleral lens wear on the corneal health of young, healthy patients. The researchers fit 27 patients (mean age 21.4±3.9 years) with fluorosilicone acrylate scleral lenses. They also randomized the patients into 2 groups, each given a different brand of saline solution.

Clinicians used fluorometry to measure the subjects’ corneal epithelial permeability to fluorescein on the central cornea of their right eyes and the temporal corneal periphery of their left eyes, at baseline, 1 month and 3 months.1 Confocal microscopy was also performed at the same intervals, but at different visits, and different distributions of corneal nerve fibers and dendritic cells.1

Mean central corneal permeability at baseline at 3 months was measured at –3.6 ln(Pdc), while at the temporal periphery it was –3.1 ln(Pdc) at baseline and –3.0 ln(Pdc) at 3 months.1 The mean dendritic cell density at center baseline was recorded at 36 cells/mm2.1 At 3 months it was 31 cells/mm2. At the inferior periphery, the researchers noted a baseline mean of 81 cells/mm2 and 71 cells/mm2 at 3 months.1 All corneal nerve fiber morphology measurements maintained similar stasis.1

The subjects were also questioned on 4 subjective measurements: comfort, visual quality, fogginess, and dryness. Comfort and visual quality each saw little change from the 1-month checkup (each were scored 85 and 83, respectively, out of 100) to the 3-month checkup (88 and 84, respectively).1 Fogginess and dryness from 1 month (11 and 22) also showed little change at 3 months (13 and 16).1

Previous studies into soft contact lens and borate-based saline solutions showed significant changes to corneal health.2 Researchers say these changes were not observed in this study. “This provided further evidence to support the increasing popularity of scleral lens wear on healthy subjects,” according to the researchers. 

The researchers say this study shows that scleral lens wear for 3 months on healthy corneas of young subjects did not affect corneal epithelial barrier function, nerve fiber, and dendritic cell densities.

1. Tse V, Zhou Y, Truong T, Lin K, Tan B, Lin MC. Corneal health during three months of scleral lens wear. Optom Vis Sci. 2020;97(9):676–682. doi: 10.1097/OPX.0000000000001566

2. Lin MC, French HM, Graham AD, Sanders T. Effects of daily irrigation on corneal epithelial permeability and adverse events with silicone hydrogel contact lens continuous wear. Invest Ophthalmol Vis Sci. 2014;55:776–83. doi: 10.1167/iovs.13-13508