This case study highlights the versatility of the scleral lens’ ability to vault irregular profiles and toricity, as well as the lens’ ability to overcome challenges associated with patient misperceptions and hesitation with the large GP lenses.  

Case Description

A 40-year-old male, who works in the banking industry, was referred for a right eye scleral lens evaluation and fitting after undergoing corneal transplant surgery. Per the surgeon’s advice, after allowing his sutures to heal for 1 year, he was evaluated for a scleral lens. This patient had a challenging history. Initially, he developed keratoconus in his teenage years. A cross-linking procedure in 2017 was unsuccessful and lead to scarring and increased signs and symptoms of keratoconus (KCN). Then, in 2018, another provider attempted a scleral lens fit. Unfortunately, the patient was never able to achieve lens comfort and adequate wearing time that left him hesitant to try scleral lenses again.  

Subsequently, in 2022 he had a successful penetrating keratoplasty (PKP) procedure, which provided a smooth but oblate central cornea surface with irregularity at the intersection of the graft/host area. At that time, he was able to achieve 20/70 OD with a -15.00D corneal contact lens.

The patients post-surgical keratometry was 53.00 /45.75 @ 156. The FAQT Scleral lens (Visionary Lens) was used due to its ability to match the toric characteristics with the surface profile irregularity of the cornea. Based on the K readings and significant corneal toricity, the fitting set lens Q4-H with a 7.58mm base curve, 4550 SAG, and 250 micron overall toricity was selected. The lens is fabricated in the Acuity 200 (Acuity Polymers) GP material and plasma cleaned to enhance comfort and wettability even further.  

The patient’s hesitation was immediately relieved upon application of the lens. He reported no feeling of pain or discomfort and obtained 20/20 OD after the lens settled. Unfortunately, there was some lens bearing at the elevated suture location with the first fit (Figure 1).

Due to the irregular cornea profile caused by the sutures the lens had to be redesigned to provide clearance in three locations on the eye profile, the apex, the graft interface, and the limbus.

Discussion

Fortunately, the versatility of the scleral lens design allows changes to two parameters simultaneously to achieve the desired clearances over the entire surface of the eye. This lens was redesigned by reducing the width of the second curve to avoid interference with the graft interface. In addition, overall SAG had to be increased by 200 microns to ensure clearance over the three crucial features of the cornea profile.  

The inherent overall toricity of the scleral lens design was able to accommodate the circumferential cornea toricity caused by the asymmetric graft. The final fit resulted in a lens with adequate clearance over the apex, graft interface and sclera (Figure 2).

Conclusion

A successful scleral lens fit was developed for a highly irregular cornea by simultaneously varying two parameters on the design to provide necessary clearance in multiple locations on the eye profile. 

Ethan Clayton, OD, owns Optometric Center at Moreno Valley in Moreno Valley, Calif. He has no disclosures to report.