Contact Lens Case Reports
A Scleral Lens Success Story
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRÉ, FAAO
Our patient underwent bilateral, 16-incision radial keratotomies in 1988. Post-operatively his right eye refractive error was +2.00 −1.25 × 22 with a visual acuity of 20/20. However, his left eye refractive error was +6.50 −2.25 × 170 with a visual acuity of 20/25.
To manage the left eye overcorrection, the surgeon performed a hexagonal keratotomy (Figure 1), a corneal steepening technique proposed in the 1980s for correcting hyperopia. It consisted of six hexagonal incisions covering the central 5.5mm of the cornea. The technique failed to produce consistent hyperopic corrections and was abandoned by the early 1990s. When employed with the radial incisions, the 16 intersecting incisions or “T” cuts resulted in significant irregular corneal astigmatism and asymmetry (Figure 2a).
Throughout the years, the patient experienced many unsuccessful attempts with a range of contact lenses and for the past 10 years has elected to live with monocular vision.
Six months ago the patient was seen for a scleral lens fitting on his left eye. At the examination, his simulated keratometric readings were 38.87 @ 14/44.12 @ 104 with 5.25D of corneal astigmatism; manifest refraction was +6.00 −3.25 × 10 20/50. Anterior segment optical coherence tomography showed a highly irregular anterior corneal surface (Figure 2b). However, the peripheral cornea and the sclera were within normal limits with a sagittal depth from the 10.0mm to 15.0mm chord of 1,980 microns (normal is 1,992 microns) and peripheral angles of 36.9 degrees and 38.7 degrees (normal is 38 degrees). It was clear from this examination that his pathology was confined to the center 10.0mm of his cornea.
Figure 1. The patient’s left eye with the combination radial and hexagonal keratotomies.
Figure 2. (a) corneal topography and (b) anterior segment OCT of the patient’s left eye.
Figure 3. Scleral lens diagnostic fitting (a) inadequate sagittal depth (b) appropriate sagittal depth and (c) OCT image.
Finding the Correct Lens
We began diagnostic lens fitting by applying a scleral lens with a sagittal depth of 4,200 microns to the left eye. The lens clearly showed inadequate apical clearance (Figure 3a). It was replaced with a diagnostic lens 300 microns deeper with a sagittal depth of 4,500 microns (Figure 3b). This lens showed an appropriate amount of initial apical clearance of 410 microns (Figure 3c). We performed a manifest refraction over the diagnostic lens with an endpoint visual acuity of 20/25.
The scleral lens was manufactured and dispensed, and the patient’s visual acuity with the lens was 20/25. On follow up, he reported 14 hours a day of comfortable lens wear and complete return of his binocular vision.
Many May Benefit
This case illustrates one of the many people who can benefit from modern scleral lenses. CLS
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant to Paragon Vision Sciences. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.