The effect of various types of COVID-19 vaccines on the retinal microvasculature.

PURPOSE: To detect the effect of various types of COVID-19 vaccine on macular and optic disc microvasculature. METHOD: One hundred subjects receiving various types of COVID-19 vaccine (AstraZeneca, Sinopharm, Sinovac, Pfizer, and Moderna) were included in this study. A complete ophthalmic examination was done which included best-corrected visual acuity measurement, slit-lamp biomicroscopy, intraocular pressure measurement with Goldmann applanation tonometry, and fundus examination. Optical coherence tomography angiography (OCT-A) was done before and 1 week after receiving the vaccine. Superficial and deep macular capillary densities were measured in the form of the whole image, fovea, parafoveal, and perifoveal capillary density. Optic disc vessel density in the form of the whole disc, inside disc, and peripapillary were also measured. RESULTS: The superficial macular vessel densities, (whole image, fovea, parafoveal, and perifoveal) showed statistically non-significant changes with P-values (0.269, 0.167, 0.346, and 0.476) respectively. Also, the deep macular vessel densities showed statistically non-significant changes with P-values (0.491, 0.096, 0.724, and 0.386) for the whole image, fovea, parafoveal, and perifoveal respectively. Moreover, RPC (radial peripapillary capillary) density showed no significant changes either (the whole disc, inside disc, or peripapillary) with P-values (0.807, 0.141, 0.883) respectively. CONCLUSION: Various types of COVID-19 vaccines had no statistically significant effects on macular or optic disc microvasculature.

Comparison between hyaluronic acid filler and botulinum toxin type A in the treatment of thyroid upper eyelid retraction.

PURPOSE: The aim of this study was to compare between hyaluronic acid filler (HA) and botulinum toxin type A (BTX-A) in the treatment of thyroid upper eyelid retraction. STUDY DESIGN: This was a prospective comparative study. METHODS: A total of 50 eyes with upper thyroid eyelid retraction were divided into 2 groups. Each group included 25 eyes, (a) hyaluronic acid filler (HA) group: received subconjunctival HA injection and (b) botulinum toxin (BTX-A) group: received subconjunctival botulinum toxin type A injection. Full ophthalmic examination and thyroid profile were done. Marginal reflex distance 1 (MRD1) and total palpebral fissure height (TPFH) were measured before and after injection weekly for 6 months. RESULTS: There is no significant difference between the two groups regarding MRD1 till the 10th week of follow up, then it became significant from the 11th to 15th week with better results in HA filler group, then the difference between the two groups become highly significant from the 16th week afterward with better results for the HA filler over the BTX-A. With regard to TPFH, there were significant differences between the BTX-A group and the HA group with a better result in BTX-A group in the first 8 weeks. Then the difference became insignificant till the 18th week. Then the difference became significant from the 19th till the 24th week with a better result in HA group. CONCLUSION: HA filler has better result in treating thyroid upper eyelid retraction than BTX-A due to its predictable controllable effect, also, due to the longer duration of action and fewer side effects.