Contact Lens Case Reports
Using Scleral Lenses to Determine Vision Potential
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRÉ, FAAO
Our patient was a 42-year-old male who suffered a nail gun injury to his left eye in 2010. The injury perforated the cornea, resulting in a drawn pupil with some lens opacification. The referring ophthalmologist indicated that the retina was intact and appeared unaffected by the trauma. The patient’s right eye was normal, with a nasal pterygia that appeared to have no effect on the central corneal topography (Figure 1). The patient was referred to our clinic for a contact lens refraction to determine his best-corrected visual acuity (BCVA) and potential for wearing a contact lens on his left eye.
Figure 1. Corneal topography of the patient’s right eye.
Figure 2. Axial display and elevation display maps of the patient’s traumatic left eye.
Simulated keratometric readings were OD 41.50 @ 170/42.25 @ 80 with 0.75D of corneal astigmatism and OS 45.62 @ 108/52.62 @ 018 with 7.00D of corneal astigmatism. An elevation map of the left eye revealed that with a 7.67mm (44.00D) reference sphere, portions of the superior cornea were elevated 389 microns above the spherical surface, while the inferior cornea was depressed −113 microns below the reference sphere (Figure 2). This 500+ micron difference in corneal height made it difficult to achieve a stable lens fit with traditional GP lens designs.
Anterior segment optical coherence tomography (OCT) of the patient’s left eye indicated a sagittal height (at a chord of 15.0mm) of 3,350 microns (Figure 3). We selected a scleral diagnostic lens with a sagittal depth 550 microns deeper to ensure appropriate lens clearance over the more elevated peripheral cornea. The fluorescein pattern showed adequate corneal clearance both centrally and peripherally. A sphero-cylindrical over-refraction indicated that the patient’s BCVA was 20/100. The position of his corneal scar and the cataract were the most likely causes of his decreased acuity.
Figure 3. Anterior segment OCT of the patient’s left eye.
Figure 4. White light and fluorescein image of the scleral lens on the patient’s left eye.
We instructed the patient to return to his cornea specialist to determine whether he should undergo a “triple procedure” of a cataract extraction, intraocular lens implantation, and a corneal transplant.
This case demonstrates how a well-centered scleral lens can be used for diagnostic purposes to determine BCVA. CLS
Patrick Caroline is an associate professor of optometry at Pacific University. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.