Abstract:Objective: To explore the changes of microcirculation of the bulbar conjunctiva after wearing the scleral lenses. Method: Prospective clinical study. The healthy students from Wenzhou Medical University were included in this study. The subjects randomly selected one eye as the experimental subject according to the random number table, the experimental subject wore scleral lenses. Functional slit lamp biomicroscopy (FSLB) was used to capture temporal bulbar conjunctival microcirculation and microvascular images under the lenses and outside of the lenses before and during the wear at 0 h, 1 h, 2 h and 3 h. Custom-built software has been utilized for the quantification of microvascular morphology and hemodynamics. The changes of the indicators before and during wearing the scleral lenses were observed. The microcirculation and microvascular parameters were analysed using ANOVA and Pearson correlation. Result: 22 subjects were enrolled in the study, including 13 right eyes and 9 left eyes. Outside of the scleral lenses, the vessel density before wearing lenses (1.408±0.124) was less than that at 0 h(1.482±0.100) (P=0.019).Outside of the scleral lenses, the blood flow volume was (104.5±28.4)pl/s before wearing lenses and (86.1±20.9)pl/s after wearing 1 h. The comparison before and after wearing the scleral lenses was statistically significant (P=0.027). Under the scleral lenses, the vessel diameter at 3 h (18.39±1.90) μm was statistically significant (P<0.05) from before wearing the lenses (17.71±1.49) μm and after wearing the lenses at 0 h (17.63±2.11) μm, 1 h (17.85±1.86) μm. The vessel diameter at 0 h after lens insertion was decreased than before lens wearing, however, the vessel diameter was increased after 1, 3 h wearing. The blood flow volume at 1 h [(61.6±22.8)pl/s ]was less than that before wearing lenses (77.4±27.0)pl/s and at 3 h [ (76.9±22.3)pl/s] (P<0.05). The comparison of 1 h after wearing the scleral lenses and before wearing lenses, 3 h after wearing the scleral lenses was statistically significant. Conclusion: At the beginning of wearing the scleral lenses, the bulbar conjunctival vessels suffered transient circulatory disturbance due to the pressure of the scleral lens. Then the microcirculation of the bulbar conjunctiva increased due to the gradual adaptation of the scleral lenses and the inflammatory stimulation. The study of the conjunctival microcirculation and microvascular may contribute to explore the safety of wearing the ScCL and monitoring conjunctiva vascular system in long-term scleral lenses wearers
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