Clinical science effects of different mydriatics on retinal and choroidal parameters in healthy adults observed by widefield swept-source optical coherence tomography.

Purpose: To assess retinal and choroidal changes following rapid mydriasis in healthy adults.

Methods: Seventy-one volunteers (71 right eyes) participated in a prospective randomised controlled trial. They were divided into two groups: tropicamide (n=36) and a mixture (tropicamide:phenylephrine=1:1, n=35) groups. Ophthalmic examinations included visual acuity, intraocular pressure and axial length measurements. Ultra-widefield swept-source optical coherence tomography angiography was used to assess retinal and choroidal parameters before and after mydriasis. This technique covers a 24×20 mm² area, allowing for non-invasive, simultaneous structural and haemodynamic assessment of retinal and choroidal regions.

Results: Both central (tropicamide: 33.3%; mixture: 22.22%) and mid-peripheral (tropicamide: 28.47%; mixture: 36.81%) retinas thickened slightly postmydriasis (p<0.05, false discovery rate (FDR) corrected). Specifically, thickening primarily occurred in the temporal (tropicamide: 25.61%; mixture: 34.31%) and inferior (tropicamide: 50.00%; mixture: 35.29%) mid-peripheral regions. Outer retinal layer thickening correlated positively with overall retinal thickness in both groups (tropicamide: r=0.71, p<0.001; mixture: r=0.74, p<0.001). Choroidal stroma volume increased in 18 regions post-tropicamide treatment and in two regions postmixture treatment (p<0.05, FDR corrected). However, no significant differences were found in retinal vascular density, choroidal thickness, vascular density or matrix between the two groups premydriatic and postmydriatic administration (p>0.05, FDR corrected).

Conclusions: Rapid mydriasis causes slight retinal thickening, the slight change in the outer layer, particularly in the temporal and inferior regions. There were no significant changes in the choroid parameters following mydriasis, except for choroidal stroma volume. The limitation of this study was the small sample size and the absence of a control group.