Comparison of the influence of corneo-scleral and scleral lenses on ocular surface and tear film metrics in a presbyopic population

Purpose

To assess and compare the effect of the corneo-scleral lenses (C-ScL) and scleral lenses (ScL) on tear film parameters and central corneal thickness (CCT) in healthy presbyopic subjects.

Methods

Thirty subjects wore two contact lenses (CLs), randomly assigned, of neutral power, but of different diameters, 12.7 mm (C-ScL) and 18 mm (ScL) and being equal in the others parameters: material (HS100) and centre thickness (0.29 mm). At baseline, 20 min after insertion and at 8 h, the tear meniscus area (TMA) and CCT was measured (with optical coherence tomography) as well as tear osmolarity.

Results

TMA revealed statistical differences for both lenses at 20 min (p < 0.001), and also at 8 h (p = 0.003), being greater for the C-ScL. CCT showed statistical differences for both lenses at 20 min (p = 0.002), and also at 8 h (p = 0.001), being lower for the C-ScL. Osmolarity did not reveal statistical differences at 20 min (p = 0.29), while it was statistically different at 8 h (p = 0.03), being lower for the C-ScL.

Conclusions

C-ScL lead to a lesser reduction in the TMA and a lower induced hypoxic stress than the ScL. Osmolarity levels remained within normal values across the day with no clinical difference between lenses. Both designs can represent a good optical platform for correcting presbyopia as well as protecting the ocular surface by vaulting the cornea.