Scleral Lenses Linked to Visual Improvements for Patients With Keratoconus

Scleral contact lens use significantly improved visual acuity in people with keratoconus compared with glasses and rigid gas permeable contact lenses, although it came with a small increase in mean intraocular pressure (IOP), according to research published in Therapeutics and Clinical Risk Management. 

 Researchers evaluated a total cohort of 60 eyes (21 men; mean age, 38.4 years ± 11.8 years) with varying grades of keratoconus, as defined by the Krumeich classification. All participants were unsatisfied after vision corrections with glasses or corneal rigid gas permeable lenses. Baseline measurements included distance corrected visual acuity, anterior central and posterior corneal curvature, corneal pachymetry, iridocorneal angle, anterior chamber depth and volume, and IOP. 

Customized scleral contact lenses were then prescribed to all 30 participants and inserted using saline and sodium fluorescein, then assessed via slit-lamp biomicroscope. IOP during contact wear was assessed at baseline and 8 hours to document comfort and visual acuity. The lenses were removed, and IOP was measured again via Goldmann applanation tonometer (GAT) and diaton tonometer (DT). 

Mean logMAR visual acuity improved from approximately 0.2 with glasses and 0.1 with rigid gas permeable contact lenses to -0.02 in all eyes with scleral contact lenses (P <.05). All patients reported that the scleral contact lenses were comfortable, with mean daily wear time longer than 6 hours. Investigators did not find a significant difference in IOP before or after lens wearing and removal for either GAT or DT (P =.45 and P =.31, respectively). 

Results of a t-test performed on DT results before and during lens wearing indicated a significant increase in IOP; similar results were found when comparing DT-measured IOP with DT during and after lens removal. Per investigators, these results demonstrate a small but statistically significant DT increase in IOP with scleral contact wear. 

Scleral contact lenses give a valid alternative to surgery with quality of vision and comfort superior to other devices, according to the study.  While researchers report that DT demonstrated a small but significant rise in IOP during scleral contact lens wear, they believe it is unlikely to cause glaucomatous damage, especially in otherwise healthy eyes. 

Reference 

Formisano M, Fanzone F, Alisi L, Pistella S, Spadea L. Effects of scleral contact lenses for keratoconus management on visual quality and intraocular pressure. Ther Clin Risk Manag. 2021;17:79-85. doi:10.2147/TCRM.S293425.