ABSTRACT
Purpose: To observe the effects of caffeine intake on vessel densities in macular and peripapillary regions and to analyze the correlations of vascular properties of these two interlinked regions in healthy volunteers using optical coherence tomography angiography (OCTA). Methods: In this prospective randomized, double?masked, placebo?controlled study, 120 participants were grouped into two groups: sixty subjects as a study group, which received caffeine and sixty subjects as a placebo group, which received a placebo. OCTA imaging was performed at baseline and 1 h after drug intake. Changes in macular and radial peripapillary capillary (RPC) vessel densities (VD) and foveal avascular zone (FAZ) parameters and correlation of these parameters were analyzed. Results: Baseline macular and RPC VD and FAZ parameters showed no significant difference between study and placebo groups (P > 0.05 for all). VD parameters in all segments of superficial and deep macular regions and peripapillary region showed a statistically significant decrease after caffeine intake (P < 0.001 for all). All macular superficial VD parameters showed a positive correlation with deep perifovea VD (P < 0.05 for all). Also, superficial perifovea VD was positively correlated with all deep macular VD parameters except deep fovea VD (P < 0.05 for all). Conclusion: We show that caffeine causes a decrease in macular and peripapillary vessel densities in healthy subjects, and correlations were observed between macular and peripapillary VD parameters. We believe that future studies are needed to support the effect of caffeine on peripapillary VD and the idea of using deep perifovea VD as the main parameter to estimate superficial macular parameters.
ABSTRACT
AIM:To use in vivo spectral-domain optical coherence tomography (SD-OCT) to investigate ocular surface epithelial thickness changes in patients treated with oral isotretinoin.METHODS:A total of 64 eyes of 64 acne vulgaris patients were enrolled into two group:thirty-two patients received 0.5 mg/kg isotretinoin daily (Group A),and the other 32 patients received 0.8 mg/kg daily (Group B).The central corneal thickness (CCT),central corneal epithelium thickness (CCET),central corneal epithelium basal membrane thickness (CCEBMT),non-epithelial central corneal thickness (NECCT) and bulbar conjunctival epithelium thickness (BCET) were evaluated using SD-OCT at baseline,at the 45th day,at the fourth month of treatment and at the first month after the end of treatment.RESULTS:There were 44 females (68.75％) and 20 males (31.25 ％) with a mean age of 21.68±3.75y.In both groups,CCET,CCT and BCET were significantly thinner at the 45th day,at the fourth month of the treatment and at the first month after the end of treatment as compared with baseline.CCEBMT decreased significantly at the 45th day and at the fourth month of treatment,but there was no difference between the baseline and the last visit.There were no significant difference in NECCT during and after treatment as compared with the baseline.CONCLUSION:Ocular surface epithelial thickness decreased in patients treated with oral isotretinoin,whereas NECCT was not affected.The decreasing corneal thickness in patients treated with isotretinon is mainly due to epithelial thinning.After a one-month cessation of isotretinoin treatment,CCEBMT returned to the baseline value,and ocular surface epithelial thickness increased.