Altered Bulbar Conjunctival Microcirculation in Response to Contact Lens Wear.

PURPOSE: This study was conducted to determine blood flow velocities and corresponding vessel diameters to characterize the response of the bulbar conjunctival microvasculature to contact lens wear.

METHODS: A functional slit-lamp biomicroscope (FSLB), an adapted traditional slitlamp, was used to image the temporal bulbar conjunctiva of 22 healthy subjects before and after 6 hr of contact lens wear. All of the measurable venules on the conjunctiva were processed to yield vessel diameters and blood flow velocities.

RESULTS: The average blood flow velocity increased from 0.51±0.20 to 0.65±0.22 mm/sec (P<0.001) after 6 hr of lens wear. The blood flow velocity distribution showed a velocity increase that correlated with the vessel diameter increase from the baseline (r=0.826, P<0.05). This pattern maintained a similar trend after 6 hr of lens wear (r=0.925, P<0.05), and increased velocities were found across all of the vessel diameter ranges (P<0.001).

CONCLUSIONS: Blood flow velocity increases across all of the vessel diameter ranges in response to contact lens wear. Functional slitlamp biomicroscope is capable of characterizing the bulbar microvascular response to contact lens wear.