Clinical Ophthalmology (Dec 2023)
Evaluation of Foveal Avascular Zone After Strabismic and Anisometropic Amblyopia Therapy in Saudi Children Using Optic Coherence Tomography Angiography: A Cohort Study
Abstract
Gorka Sesma,1 Tasnim Al Mairi,2 Heba Fareed Khashoggi,1 Shorog Ibrahim AlDhahi,1 Fahad Aljohar,3 Rajiv Khandekar,4 Abdulaziz Awad1 1Pediatric Ophthalmology and Strabismus Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia; 2Emergency Department, Almoosa Specialist Hospital, Al Mubarraz, Saudi Arabia; 3Diagnostic and Imaging Department, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia; 4Department of Vision Science, University of British Columbia, Vancouver, CanadaCorrespondence: Gorka Sesma, Pediatric Ophthalmology and Strabismus Division, King Khaled Eye Specialist Hospital, Al Urubah Branche Road, West Building 2nd Floor, Riyadh, 11462, Saudi Arabia, Tel +966 11 4849700, Fax +966 11 4821908, Email [email protected]: Optical coherence tomography angiography (OCTA) noninvasively images retinal microvasculature. Foveal avascular zone (FAZ) biomarkers can act as indicators of various forms of amblyopia, making them valuable tools for clinicians. The purpose of this study was to assess the effect of amblyopia therapy on the FAZ using OCTA to determine FAZ size in children with untreated amblyopia.Patients and Methods: This two-arm cohort study enrolled 23 children with untreated strabismic or anisometropic amblyopia who underwent OCTA between 2021– 2022. Each arm had 23 eyes, with one arm having amblyopic eyes and the other having normal eyes. FAZ area, perimeter, and circularity index were measured before and quarterly during 1 year of occlusion therapy. Differences in avascular zone biomarkers between amblyopic and fellow eyes were compared and linked to demographic and ocular factors.Results: Similar FAZ areas were found in the amblyopic (0.3 mm2) and nonamblyopic eyes (0.28 mm2) (P = 0.83), with no significant change in either group (P = 0.93). Amblyopic eyes showed a larger FAZ perimeter reduction (0.12 mm2) than fellow eyes (0.02 mm2), but the difference was not statistically significant (P = 0.09). The circularity index in amblyopic eyes matched with fellow eyes (0.67 mm2), P = 0.38. Initial visual acuity and strabismus correlated with changes in the follow-up FAZ area.Conclusion: Amblyopia treatment did not significantly alter FAZ area in this cohort. Perimeter variations between amblyopic and fellow eyes require further study. The conclusions were limited by the sample size and lack of randomization.Plain Language Summary: Amblyopia is a common vision problem in children in which one eye does not see the fellow eye. This can occur if the eyes are not lined up right or if their prescriptions are different. Amblyopia is treated by placing a patch over the stronger eye to help the weaker eye better see.Researchers have used a technique called optical coherence tomography angiography (OCTA) to compare the foveal avascular zone (FAZ) before and after treatment in children with amblyopia. The FAZ is a spot on the back of the eye where there are no blood vessels or light-sensitive cells. Changes in the FAZ may indicate the severity of amblyopia.The study included 23 children with untreated amblyopia. Over the course of more than a year, measurements of FAZ area, perimeter, and roundness were taken before and during occlusion therapy. The size of the FAZ was also compared between the eyes with and without amblyopia.At the start of the study and after treatment, there were no significant differences between the FAZs of amblyopic eyes and other eyes. There were some differences in the size of the FAZ between eyes. Changes in the FAZ area were linked to the initial state of vision and misalignment.Overall, this study found that occlusion therapy did not change FAZ area in children with amblyopia. More research is needed to determine why the FAZ perimeter can differ between the eyes. Larger randomized studies would provide more information about how the FAZ changes when treating amblyopia.Keywords: amblyopia, optical coherence tomography angiography, foveal avascular zone, occlusion therapy, biomarkers
