Contact Lens Case Reports
Using the Toric Sclera to Position a Pinguecula Notch
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRÉ, FAAO
Fitting scleral contact lenses is often complicated by elevated abnormalities within the area of the bulbar conjunctiva, such as pingueculae, pterygia, and filtering blebs. In recent years, we have employed smaller-diameter scleral designs (14.5mm or smaller) that may rest inside the elevation; larger-diameter scleral designs (18.0mm and larger) that may rest over the elevation; notches that are beveled into the lens periphery to “work-around” the elevation; and micro-vaults that create a flute or ripple in the edge to vault over the elevation.
Stabilizing Scleral Lenses
Historically, when making modifications to the lens periphery, a ballasted design was required to position the treatment appropriately across the conjunctiva. This case outlines how the inherent toricity of the sclera can be used to stabilize scleral contact lenses for notching.
A 45-year-old female with a history of advanced keratoconus (OS>OD) was referred to our clinic for a refitting of the lens on her left eye. The patient was ultimately placed into a 16.5mm scleral lens. She did well with initial lens comfort and visual acuity, but complained of significant end-of-day irritation and inflammation secondary to an elevated nasal pinguecula (Figure 1).
Figure 1. Corneal topography, optical coherence tomography, and slit lamp image of the patient’s left eye.
It was determined that the patient might benefit from a notch at the 9 o’clock position. However, rather than ballasting the lens to control the position of the notch, we placed a 150µm height differential in the limbal clearance and scleral landing zones of the primary meridians; this used the inherent toricity of the sclera to position and stabilize the lens. Rotation markers were placed in the lens periphery to note the flat (highest) scleral meridian.
The posterior-toric lens design was placed on the patient’s left eye and allowed to stabilize. The rotation markers consistently positioned at 10 o’clock and 4 o’clock, indicating the position of the flat scleral meridian. We used a permanent marker to identify the position and area for the notch placement (Figure 2).
Figure 2. Marking the location of the notch on the stable toric scleral lens design.
It is important for the laboratory to apply the notch within the scleral landing portion of the lens only. If the notch is too deep, it will encroach upon the limbal clearance zone of the lens and induce bubbles.
The finished lens was re-dispensed to the patient. Two weeks later, she reported a dramatic improvement in comfort with no redness or irritation. Figure 3 shows the patient’s left eye after 10 hours of lens wear. CLS
Figure 3. The notched lens following 10 hours of lens wear.
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant to Contamac. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.