Contact Lens Case Reports
The Protective Benefits of Scleral Contact Lenses
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRÉ, FAAO
For many years, we have known about the protective properties of corneal GP lenses against airborne foreign bodies. In such cases, while the contact lens is often shattered into numerous pieces, the eye remains relatively unscathed.
A Scleral’s Protective Effect
This month’s case history involves a 62-year-old elementary school teacher with a longstanding history of bilateral keratoconus. She was fitted with scleral lenses in 2010 to manage her condition.
In the fall of 2014, she presented to the clinic reporting that one week prior, while fixing a jammed electric stapler, a staple sprang from the device and hit her left eye “with a force that put a hole through the hard contact” (Figure 1). The patient recalled that immediately after the incident, she experienced moderate pain and some conjunctival redness. She removed her left lens, and the eye remained mildly irritated for one to two days.
Figure 1. The foreign body “hole” through the scleral lens created by the airborne staple.
When the patient presented one week later, her left eye was white and quiet (Figure 2). She was wearing a backup lens, with entering acuities of OD 20/25 and OS 20/20-. We speculated that after the staple hit the lens and ricocheted away from the eye, some of the broken lens fragments entered the scleral lens tear chamber and surrounding ocular environment. These fragments caused minor abrasive injuries that manifested as the slight irritation experienced by the patient in the days following the accident.
Figure 2. The patient’s left eye one week following the injury.
An Added Safety Benefit
The large diameter (14.0mm to 22.0mm) and thick design (0.30mm to 0.45mm) of scleral lenses provide a formidable barrier and protection to both the cornea and the adjacent sclera. Additionally, they feature a deep underlying tear reservoir that acts as a cushion, further shielding the cornea from foreign body penetration (Figure 3).
Figure 3. (A) An alignment-fitting corneal contact lens with its typical 20 microns of post-lens tear film; (B) A scleral lens with its typical 200 to 300 microns of apical clearance.
This case clearly illustrates these protective properties of modern scleral lenses. Had this patient not been wearing her scleral lens, the result could have been traumatic. We are not suggesting that scleral contact lenses are a replacement for safety spectacle eyewear, but this is a remarkable example of the potential protective benefit of wearing scleral contact lenses. CLS
The authors wish to thank Maria Walker, OD, MS, for her assistance with this case report.
Patrick Caroline is an associate professor of optometry at Pacific University. He is also a consultant for Contamac. Mark André is an associate professor of optometry at Pacific University. He is also a consultant for CooperVision.