This case report describes the successful use of empirically designed scleral lenses in a patient experiencing fogging and decentration with
conventional scleral lenses. It demonstrates the benefits of additional customization when addressing complex ocular topographies.

Case Description

A 24-year-old female sought an alternative contact lens option to her habitual soft toric lenses. Her current prescription was -7.50-4.25x180 OD and OS, with visual acuity at 20/25-. She expressed interest in scleral lenses to achieve improved visual acuity and comfort. An initial pair of scleral lenses was fitted and dispensed, providing 20/20- visual acuity; however, the patient reported decreased visual acuity after a few hours of wear.

Upon follow-up, fogging in the vaulting chamber of each lens was noted, and the scleral lenses showed significant inferior-temporal decentration in both eyes. The lenses were redesigned to tighten the edges where fluorescein influx was observed after settling. Although the newly redesigned lenses provided some improvement, the patient continued to experience fogging after an hour of wear.

Profilometry measurements were obtained for each eye. The elevation differential OD was 298 µm, averaged across the flat and steep meridians, with an even greater inter-quadrant difference along the 17 mm chord. The OS measurement showed similar results, with an average elevation difference of 279 µm between the steep and flat meridians, likely contributing to the decentration. A Bi-Elevation trial lens with a 300 µm sag difference was evaluated for each eye. While vertical centration improved, some inferior-temporal decentration persisted.

OCT was used to measure clearance in various zones of the fit after settling. Central and paracentral clearances along the horizontal and vertical meridians were assessed, with the flat meridian located along the horizontal (Figure 1). Edge alignment was evaluated in each quadrant, along with clearance over the limbal zones in the nasal, temporal, superior, and inferior areas. The clearance values and profilometry data were shared with a consultation team, and empirically designed Zenlens ECHO (Bausch + Lomb) lenses were created.

The OCT measurement along the paracentral vertical meridian revealed decentration. The top image shows a scleral lens with toric edges, where there is significantly more decentration, indicated by the clearance difference between the superior (right side) quadrant and the inferior (left side) quadrant. This clearance difference was offset with improved centration through the customized scleral lens (bottom).

Discussion

These scleral lenses were trialed in-office, demonstrating excellent centration and evenly distributed clearance in the paracentral and limbal areas. The edges were well-aligned, and the patient reported a comfortable wearing experience. Visual acuity was 20/15 in each eye. The lenses were dispensed for a trial period, and the patient later returned for a settling assessment. The issue of lens fogging was resolved, providing the patient with excellent visual acuity and the ability to wear the lenses continuously throughout the day.

This case illustrates the advantages of additional customization in scleral lenses when issues like fogging and decentration occur. While simpler methods—such as toric or custom edges and vaults—can address many fitting challenges, some patients exhibit significant scleral elevation differences that may benefit from more tailored designs with varied vaults and edges in different quadrants. This approach can enhance lens performance for such patients. 

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Dr. Gidosh is chief of Contact Lens Services and assistant professor of optometry at Pennsylvania College of Optometry at Drexel University. He is a Fellow of the American Academy of Optometry. He is a paid consultant for Bausch + Lomb.