While corneal gas permeable (GP) lenses have been a mainstay of keratoconus treatment, scleral lenses are gaining an edge as the initial correction for these patients. Comparing patient satisfaction and burden of care between these two specialty lenses, a new study in Optometry and Vision Science found keratoconus patients reported higher levels of comfort and visual satisfaction with sclerals.

Nonetheless, both groups reported cloudy vision and lens discomfort, the team of researchers noted.

The National Keratoconus Foundation distributed an electronic survey over a six-month period and collected data on age at diagnosis, initial and current treatment, lens complications, access to care, lens handling time and annual out-of-pocket treatment costs. Additionally, vision, lens comfort and ease of use satisfaction were rated from one to five.

The study analyzed a total of 422 responses, including 75 bilateral GP and 76 bilateral scleral lens wearers.

When comparing sclerals to GP lenses, the researchers found scleral lens wearers had greater satisfaction with vision (3.2 ± 1.1 vs. 2.6 ± 1.1) and comfort (3.3 ± 1. vs. 2.2 ± 1.2), but similar ease of use satisfaction in both groups.

Because scleral lenses confer stability and can provide centration of the lens optics over the visual axis, clinicians often assume that scleral lenses will provide a superior visual experience for patients with keratoconus, the researchers noted. However, the study found vision difficulties were commonly reported in both GP and scleral lens wearers in nearly equal numbers. Of note, more than 70% of patients in each group reported some level of visual disturbance.

Both groups reported issues with cloudy or foggy vision (GP, 63%; scleral, 58%) and contact lens discomfort (GP, 77%; scleral, 67%). Although GP wearers reported more issues with lens movement or loss than scleral lens wearers (40% vs. 18%), they had fewer difficulties with halos (53% vs. 72%) and lens handling (40% vs. 63%) compared with scleral lens wearers.

Other key findings: GP (48%) and scleral lens (45%) wearers spent six to 10 minutes daily handling their lenses.

Looking at cost, most participants estimated their annual out-of-pocket lens cost was in the lower study range of $0 to $999, although GP lenses tended to be cheaper. The study found 60% of GP wearers spend less than $1,000 on their lenses each year, while only 41% of scleral lens wearers said the same.

Additionally, although scleral lens wearers spent more time on lens care and handling than did their GP-wearing counterparts, perceived ease of use was comparable between the two groups.

Many practitioners still consider GP lenses the most appropriate first-line therapy, and a majority of scleral lens wearers (74%) had previously worn GP lenses, the researchers noted.

One could assume that at least some of these patients were refit with scleral lenses when disease progression made it impossible for them to wear corneal gas-permeable lenses safely and comfortably, or after the cornea had begun to scar, the investigators suggested.

"Over 50% of respondents wearing either corneal gas permeable or scleral lens wearers reported issues with lens discomfort and cloudy vision, but scleral lens users reported higher overall satisfaction with vision and comfort compared to corneal lens wearers," says researcher Ellen Shorter, MD. "Respondents in both groups reported similar satisfaction with ease of use, and both groups reported spending similar amounts of time on lens care during the course of the day.  As scleral lens prescription continues to increase, it is important to consider patient-reported outcomes and care burden of their therapeutic lenses."