Researchers from the Ocular Surface Institute at the University of Houston College of Optometry recently discovered elevated levels of inflammatory markers—namely matrix metalloproteinase-9 and -10 (MMP-9, MMP-10)—in scleral lens fluid reservoirs compared with those found in basal tear samples, indicating potential clinical issues with these lenses.

Their study enrolled 15 normal, habitual soft contact lens wearers who were fitted with 14.8mm or 15.4mm scleral lenses. The investigators collected basal ocular surface tears and fluid reservoir samples after eight hours and again after four days of scleral lens wear.

After eight hours, the median concentration of MMP-9 in the fluid reservoir and basal tears were 62.7ng/mL and 15.2ng/mL, respectively. Likewise, MMP-10 was significantly greater in the fluid reservoir compared with the basal tears after eight hours and four days. Additionally, researchers reported interleukin-4 and -8 (IL-4, IL-8) were relatively high in the fluid reservoir, yet not significantly so, at eight hours and at four days.

While certain markers were found to be elevated, MMP-7 remained unchanged at both time points.

No changes were found in visual acuity or corneal or conjunctival staining, but participants said their comfort was reduced while wearing the scleral lenses compared with their usual soft contacts.

This is the first study to compare the fluid reservoir with basal ocular surface tears, the researchers said.