The Scleral Lens Vault
Prescribing Scleral Lenses for Regular Corneas
BY GREGORY W. DENAEYER, OD, FAAO
Scleral contact lens prescribing has dramatically increased since 2008. Specialty contact lens fitters who prescribe scleral lenses have become more familiar with their fitting and design principles, which are different from any other lens modality. It’s a natural progression that such specialty fitters are beginning to consider using scleral lenses to provide refractive correction for patients who have regular corneas.
Patients who have high myopia or hyperopia and have failed with traditional contact lens designs are candidates for scleral lenses.
Also, scleral lenses may be ideal for patients who have moderate-to-high amounts of astigmatism and have failed in soft lens designs because of rotational instability. Scleral lenses will typically be more stable compared to corneal GPs when fitting against-the-rule astigmatism or when using front-surface toricity to correct for lenticular astigmatism.
For presbyopic patients, scleral lenses can be manufactured with multifocal designs or set up with monovision.
Patients who have dry eye may also succeed with scleral lenses. Stephanie Woo, OD, FAAO, a specialty contact lens fitter from Lake Havasu, Ariz., states: “I have had many patients who have dry eyes, but not severe ocular surface disease, whom I have fit with scleral lenses designed for normal corneas. These scleral lenses are typically much easier to fit and manage because normal corneas have predictable shapes and normal eccentricity values. These patients are some of the most successful and satisfied in terms of comfort, vision, and wear time.”
Regarding lens size, corneal-scleral or mini-scleral lenses are probably the best option for normal corneas (Figure 1). However, completely vaulting the cornea is preferable, especially for patients who have dry eye.
Figure 1. A mini-scleral lens on a regular cornea.
Larger, full scleral lenses are unnecessary because there is no need to vault extreme amounts of corneal sagittal depth that you might see in ectatic eyes. In addition, fitting a relatively smaller scleral lens will increase the probability that the haptic will have a more even circumferential fit because these lenses avoid the more asymmetric areas of the sclera. Additionally, patients will have an easier time with application using mini-scleral lenses versus large scleral designs.
Using hyper-Dk GP materials is necessary because these lenses have little to no tear exchange secondary to their semi-sealed fitting relationship. Ideally, the goal is to completely vault the cornea and avoid corneal bearing, which results in corneal epithelial or limbal cell compromise.
A patient will need to have adequate dexterity to apply and remove scleral lenses.
Patients who are currently limited to glasses because they have been unable to wear traditional soft and corneal GP lenses may be great candidates for scleral lenses. Applying diagnostic lenses will demonstrate the potential that these lenses have for comfort and stable vision correction. CLS
Dr. DeNaeyer is the clinical director for Arena Eye Surgeons in Columbus, Ohio and is a consultant to Visionary Optics, B+L, and Aciont. He has financial interest in the Europa scleral lens and in a scleral lens for regular corneas currently in development with Visionary Optics. You can contact him at email@example.com.