Certain complex cases require the use of larger scleral lens diameters, ranging from 18.5 mm to 21.0 mm, with sagittal depths (sag) between 7,000 and 9,000 microns. These designs provide critical advantages for patients with advanced corneal conditions.
Case History
This patient who had advanced keratoconus (Figure 2) was first fitted in 2015. In 2018, the patient experienced a corneal hydrops in the left eye (OS), presenting with epithelial and stromal edema at the corneal apex. After treatment, the patient was refitted with a high-Dk scleral lens.
At a recent follow-up, progression of keratoconus was observed, with the original scleral lens exhibiting insufficient sagittal depth. The patient was refitted with a larger scleral lens featuring a higher sag value:
- OS: 52 x 45 (6.49 mm x 7.50 mm)
- Power: –13.00 D
- Overall diameter (OAD): 19.5 mm
- Sag: 7,269 microns
- Dk: 180
- VA: 20/25
The new lens presented a smooth haptic landing and vault over the entire cornea (Figures 3 and 4).
Discussion
Larger scleral lenses can offer superior outcomes in specific scenarios (Figures 5, 6, 7, and 8), such as:
- Large corneal diameters or wide palpebral fissures
- Advanced keratoconus
- Post-corneal transplant
- Post-refractive surgery
Beyond achieving higher sag values, large scleral lenses provide enhanced ocular surface protection, particularly in conditions like dry eye syndrome. The extended landing zone distributes lens weight across a broader area, promoting comfort and preserving ocular physiological health. Please find below references to previous publications where large scleral lens were used.1,2,3
Conclusion
Larger scleral lens designs are an indispensable tool in managing complex cases. They offer improved ocular surface coverage, better weight distribution, and enhanced comfort, ensuring optimal outcomes for patients who have advanced corneal irregularities.
References
- Bastos L. Excellence in customized scleral lens keratoconus fitting. Contamac Global Insight. 2019 November 29. contamac-globalinsight.com/case-reports/customized-scleral-lens-keratoconus
- Bastos L. Scleral lens fitting post-refractive keratotomy. Contamac Global Insight. 2021 July 29. contamac-globalinsight.com/case-reports/scleral-lens-fitting-post-refractive-keratotomy
- Bastos L. Fitting scleral lenses in a post-RK patient. Contact Lens Spectrum. 2013;28(3):32-26. clspectrum.com/issues/2013/march/fitting-scleral-lenses-in-a-post-rk-patient
