Abstract
Purpose:
To investigate structural characteristics of vitreomacular traction (VMT), especially if there is a correlation between 1) the VMT grade, central foveal thickness (CFT) and the choroidal thickness, 2) the VMT grade and the vitreofoveal angle and 3) the vitreofoveal angle, vitreomacular adhesion (VMA) and choroidal thickness.
Methods:
Images of patients with VMT were retrospectively studied at the King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia), the University of Milan (Milan, Italy), and the Truhlsen Eye Institute at the University of Nebraska Medical Center (Omaha, Nebraska, USA). Raster scans of the macula taken with a spectral-domain optical coherence tomography (SD-OCT) device were reviewed. Conventional scans of the vitreoretinal interface were analyzed to measure CFT and degree of vitreofoveal angle. Enhanced depth imaging (EDI) scans were analyzed to measure choroidal thickness in the macula. The VMT was classified based on the International Vitreomacular Traction Study Group Classification into focal (<1500 µm) and broad (>1500 µm), and isolated vs concurrent. Multivariate test of means and t-test were used to compare studied variables.
Results:
There were 54 eyes of 42 patients (15 females) in the study. There were 18 and 36 eyes with broad and focal VMT, respectively, and 10 and 44 eyes with isolated and concurrent VMT, respectively. There was no difference in the CFT between broad and focal VMT groups (p=0.31). The eyes in the broad VMT group had significantly higher nasal choroidal thickness (p=0.004), subfoveal choroidal thickness (p=0.004), and temporal choroidal thickness (p=0.002) compared to the focal VMT group. The VMT angle was more open in eyes with focal VMT compared to broad VMT (p=0.002). No significant difference was seen between the concurrent and isolated VMT groups in the vitreofoveal angle (p= 0.24). VMT angle correlated positively with the CFT (r= 0.42, p<0.001), whereas no correlation was seen between the VMT angle and the subfoveal choroidal thickness (p=0.38), nasal choroidal thickness (p=0.67) and temporal choroidal thickness (p=0.87).
Conclusions:
The eyes with broad VMT have thicker choroid and the eyes with focal VMT have more open vitreofoveal angle. Both seem to result from the tractional forces of the vitreous on the macular area. Angle of VMT influences central foveal thickness.