Scleral contact lenses remain a go-to option for keratoconus patients, and a new study in Optometry and Vision Science reaffirms that these specialty lenses provide excellent safety and efficacy for individuals with this corneal condition.
“Scleral lenses have enjoyed increasing growth and afford improved quality of life as well as restoration of visual function for most patients,” says the study’s lead researcher Daniel G. Fuller, OD, professor and chief of Cornea and Contact Lens Services at the Southern College of Optometry. “Their most common use is for patients with keratoconus. Irregular corneas, regular corneas and patients with a host of anterior segment conditions benefit from their use.”
Still, well-designed and controlled studies are lacking regarding sclerals’ safety and efficacy, he adds.
His study was designed to retrospectively review the experience of 157 eyes of 86 keratoconus patients in a large academic clinic over a five-year period by surveying the frequency and nature of adverse events as well as the ability of scleral lenses to provide improved vision.
Subjects were included regardless of age, sex, pre-existing morbidity or scleral lens design, and only those wearing lenses successfully for a year or more were included. Exclusion criteria included prior corneal surgery, dystrophy, degeneration and trauma. The mean Keratoconus Severity Score at initial fitting was 3.6 ± 1.0. Lenses were gas-permeable and non-fenestrated with a mean overall diameter of 15.8±0.6mm and 70.1% toric scleral periphery.
The researchers found that the physiological adverse events were largely of an inflammatory nature and occurred in 9.6% of eyes with only 0.6% experiencing an infectious event. These included microbial keratitis (0.6%), phlyctenulosis (0.6%), corneal abrasion (1.3%), contact lens–induced acute red eye (1.3%), corneal infiltrative events (1.3%), pingueculitis (1.3%) and hydrops (3.2%).
Additionally, 55% of eyes experienced lens-related issues, the majority of which were related to handling or soilage. These included poor wetting in 1.9%, handling in 3.8%, reservoir fogging in 7%, lens intolerance in 7.6%, deposits in 8.9% and broken lenses in 26.1%.
The most common management strategies involved refits (54% of interventions), patient re-education (29.5%), medical treatment (5.5%), surgical referral (6.8%), adjustment to wear time (2.5%), surface treatment (1.2%) and lens replacement (0.6%).
Best-corrected distance visual acuity improved significantly from a mean of 0.50logMAR in spectacles to a mean of 0.08logMAR in scleral lenses. During the study period, 14.6% of eyes lost best-corrected scleral lens visual acuity, and all were due to keratoconus progression.
“The results are consistent with other studies which show scleral lenses are overwhelmingly safe and effective at improving vision with a low frequency of adverse events,” Dr. Fuller says.
Fuller D, Wang Y. Safety and efficacy of scleral lenses for keratoconus. Optometry and Vision Science. September 11, 2020. [Epub ahead of print].