A new study suggests contact lens (CL) wearers will experience microvascular responses in the bulbar conjunctiva, regardless of the type of lens or how long they wear them—suggesting lens wear itself is the culprit.

Researchers analyzed the vessel diameters and blood flow velocities (BFVs) of 91 healthy subjects who did not wear CLs and 75 habitual soft contact lens wearers. They found lens wearers had significantly higher BFVs compared with non- wearers (0.61 ±0.15mm/s vs. 0.50 ±0.14mm/s). In addition, wearers had significantly larger vessel diameter and higher microvascular network density and complexity than non-wearers.

While BFV was positively correlated with hours of wear per day and days of wear per week, “the relationship was not strong, indicating that all CL wearers fall under a general category based on the perspective that a CL is a foreign object attached to the ocular surface that engages the vasculature to elicit a response, which has been regarded as possible subclinical chronic inflammation,” the study says.

BFV, flow rate, vessel diameter and microvascular network density and complexity were unaffected by the time of day, years of wear, lens power, base curve or diameter, “indicating that wearing a CL itself may be the predominant factor inducing these responses,” the study concludes.

Hu L, Shi C, Jiang H, et al. Factors affecting microvascular responses in the bulbar conjunctiva in habitual contact lens wearers. Invest Ophthalmol Vis Sci. 2018;59:4108-14.