Abstract
Purpose :
to perform ultrasound biomocroscopy (UBM) evaluations in eyes with silicone oil (SO) tamponades, searching for early, subclinical microstructural changes in the anterior chamber angle (ACA) tissues.
Methods :
single-center prospective study including patients undergone pars plana vitrectomy for reghmatogenous retinal detachment and placement of 3 different SOs types [2000cSt, 5000cSt and high density (DX)]. The main entry criteria included absence of previous glaucoma surgery and of anterior segment SO emulsions before tamponade removal surgery. UBM assessment was performed the day before this latter surgery, obtaining 4 ACA radial scans (nasal, inferior, temporal and superior quadrant) in the study eye, and in the fellow control one of each included patient. Scans were processed with ImageJ software [ver. 1.53k NIH]. In each quadrant of each eye (8 per patient), a right triangular area connecting the Schwalbe’s line, the ciliary body apex and the inner scleral edge was traced. This included trabecular meshwork, iris root, and ciliary body draining sections. In the areas thus identified, maximum, minimum and mean echo-reflectivity values were recorded.
Results :
33 patients were included: 11 with intraocular 2000cSt, 7 with 5000cSt, and 15 with DX tamponade. High echo-reflectivity levels were observed in the trabecular meshwork, iris root and ciliary body sections. The difference between the mean echo-reflectivity values of the study eyes and those of the corresponding quadrants of the contralateral control eyes was statistically significant in the superior quadrant for the SOs with lower density (both 2000cSt and 5000cSt groups, P=0.04 and P=0.02 respectively), and for the inferior quadrant of the DX group (P<0.01). In the study eyes, the correlation between time of tamponade intraocular permanence and number of quadrants with increased mean echo-reflectivity tested significant for the 2000cSt group (P<0.01).
Conclusions :
The statistical correspondence between the altitudinal quadrant arrangement of the increased echo-reflectivity areas and the density of the SO present in each study eye allows the ultrasound alterations to be considered tamponade-related. In the 2000cSt group, the duration of tamponade permanence in the eye correlated with the circumferential extent of the quadrants with increased echo-reflectivity in the considered ACA structures.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.