Comparison of the horizontal diameter to a modeled area of traction in eyes with vitreomacular traction: is the diameter close enough to the truth?

ABSTRACT

PURPOSE: In daily practice, vitreomacular traction (VMT) is described by the horizontal diameter of its attachment site implying a regular round shape of VMT. We investigated the deviation from this circular area of vitreous traction in patients with VMT. METHODS: A retrospective analysis of optical coherence tomography (OCT) scans was performed. The area of vitreomacular attachment was determined using six radial OCT scans (Ameasured). The assumed circular area of traction was calculated based on measuring the maximal horizontal diameter for comparison (Acircular). RESULTS: Thirty-seven eyes of 37 patients with pure VMT were included. Patients' mean age was 72.8 ± 8.2 years. Mean horizontal VMT diameter was 400.8 ± 230.5 µm (median 361 µm; range 44-991 µm). While there was no difference between mean areas of traction for Acircular and Ameasured (P = 0.93), the individual difference (|Acircular - Ameasured|) was 0.042 (± 0.044) mm2 in mean or relative 73.0% (± 135.8%). A difference of ≥ 30% of Ameasured to Acircular was found in 16 eyes (43.2%) and ≥ 100% in 7 eyes (18.9%), respectively. CONCLUSION: Vitreous attachment sites possess an irregular non-circular shape in a significant number of eyes with VMT. Consequently, the area of traction appears inaccurately described by its horizontal VMT diameter alone. As the area of traction is important for therapeutic recommendation, our results emphasize the need for a more precise description of the area of traction in eyes with VMT.