Vaulting Pingueculas

Gregory W. DeNaeyer OD FAAO FSLS

Introduction

The rigid haptic of a gas-permeable scleral contact lens should evenly rest on the bulbar conjunctiva to achieve a semi-sealed fit. Scleral obstacles, such as pingueculas, have the potential to significantly alter surface topography and cause a scleral lens to impinge or decenter. To prevent these complications, a scleral lens can be designed with an edge lift that allows the lens to vault over a pinguecula.

Pingueculas

Pingueculas are non-cancerous bumps on the eyeball and typically occur on top of the middle part of the sclera — the part that's between the open eyelids and therefore is exposed to the sun. Usually, pingueculas affect the surface of the sclera that's closer to the nose, but they can occur on the outer sclera (closer to the ear) as well (allaboutvision.com).

Key Measurements

The key measurements that are needed to design a customized edge lift include a pinguecula’s measured distance from the cornea, axis, width, and sagittal height. Measurements from diagnostic lens fitting are challenging and can be difficult to accurately report to the manufacturing consultant. Corneo-scleral topography can identify significant pingueculas (Figures 1, above) and predict how they might affect the fit of a scleral contact lens (Figure 2, below left). The precise location and sagittal height of a pinguecula can be directly measured from sagittal plot data derived from corneo-scleral topography (Figure 3, below right).

These measurements can be directly incorporated to design a customized edge lift that precisely vaults the pinguecula’s surface (Figures 4 and 5, below).



Rotational Stability

Scleral lenses with edge vaults need ballasting for rotational stability. Double slab-off prism can be used, but customized back surface toricity or a multi-meridian design is preferred secondary to improved comfort and transmissibility because they don’t require any thickness differentials (Figure 6).

Closing Remarks

Corneo-scleral topography allows for detection and precise measurement of pingueculas. Fitting software can be used to custom design edge lifts that will improve the fit, and customized toricity or multi-meridian designs can be incorporated for rotational stability.



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Greg DeNaeyer is a graduate of The Ohio State University College of Optometry. He completed a hospital based residency at the Columbus VA Medical Center. Dr. DeNaeyer practices at Arena Eye Surgeons with an emphasis on specialty contact lenses. 

Dr. DeNaeyer was a co-founder and is the past president of the Scleral Lens Education Society and is a Fellow of the American Academy of Optometry. He is a contributing editor for Contact Lens Spectrum and a contributor to Review of Cornea and Contact Lenses and Optometric Management. Dr. DeNaeyer has lectured internationally on specialty contact lenses and was the 2012 GPLI practitioner of the year.

Currently his primary research is focused on scleral lens design.