OCT analysis to determine the probability of rupture in the macula in the setting of vitreomacular traction

Abstract

Purpose : To determine the point at which there is a higher probability of rupture of the retinal layers within the macula in vitreomacular traction (VMT) syndrome.

Methods : Image analyses were conducted on pre- and post-vitrectomy OCTs of 55 patients (59 eyes) with VMT syndrome. Pre-op and post-op retinal thicknesses were manually measured as the distance from Bruch’s membrane to the inner limiting membrane at five locations within a 1000 μm area centered at the fovea including the central fovea, 500 μm nasally (N500) and temporally (T500), the highest, and the lowest points. Strain on the retina was defined as the change in thickness between the resting retina (post-op) and the retina under VMT (pre-op) divided by the post-op thickness. Mann-Whitney U and Fisher Exact tests were used to assess significance.

Results : Mean age was 74 ± 8 years with 36 women and 19 men. 47 eyes (79.7%) had tears in pre-op imaging while 12 eyes (20.3%) were not torn. Pre-op central foveal thickness was significantly different between patients with and without tears (461.5 ± 191.5 μm vs. 351.1 ± 148.0 μm, p = 0.029); however, other thicknesses including N500 (402.0 ± 139.4 μm vs. 357.1 ± 139.6, p = 0.12), T500 (415.7 ± 168.4 μm vs. 363.1 ± 129.7 μm, p = 0.20), highest (505.3 ± 193.1 μm vs, 411.2 ± 156.5 μm, p = 0.069), and lowest (369.3 ± 141.4 μm vs. 311.4 ± 95.9 μm, p = 0.18) were not significantly different. Using the 66^th percentile of highest pre-op retinal thickness (344 μm) and absolute strain (0.31) as cut-offs as shown in Figure 1 creates low (green) and high (red) risk tear groups where the percentage of retinas that are torn is 58.8% and 90.5%, respectively. A significant relationship exists between whether the retina is torn and the group it is in (p = 0.0089).

Conclusions : It is possible to determine when there is a higher likelihood of rupture of the retina by measuring retinal thickness under traction and normal retinal thickness without traction in a 1000 μm area. This data may be helpful in the planning of vitrectomy timing for patients with VMT before retinal layers dissociate under vitreomacular traction.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1: Highest pre-op retinal thickness (μm) plotted against absolute highest retinal strain showing lower risk (green) and higher risk (red) groups for retinal tears.