Axial Length Asymmetry in Patients with Unilateral Retinal Detachment

Background and Objectives: Increased axial length is a major risk factor for retinal detachment. This study explored whether, in individuals presenting with unilateral disease, the longer eye was more likely to have rhegmatogenous disease. Materials and Methods: A consecutive cohort of 276 patients (100 female; mean age 62 ± 10 years), presenting with PVD-related retinal detachment or retinal tear between 2018 and 2024 in South Australia, had their axial length measured by partial coherence interferometry. Two-sample and paired t-tests were used to compare the affected and fellow eyes. Results: There was no significant difference in the axial length between the retinal detachment eyes and fellow eyes overall (n = 181; mean AL 24.93 vs. 24.82 mm; p = 0.41), or when considering a paired analysis of those with bilateral data (n = 139, 24.69 vs. 24.71 mm; p = 0.92), with the affected eye longer in 71/139 cases. Similar results were observed for retinal tear cases (n = 80; p = 0.20) and for the entire cohort with bilateral data (n = 219, p = 0.50). Sub-group analyses by axial length asymmetry (>0.1–1.0 mm, p = 0.63–0.97) and considering only larger eyes also found no significant difference (p = 0.38–0.98). Conclusions: Within individuals, the longer eye is not more likely to present with retinal detachment or retinal tear. This suggests that axial length is associated with, but not causative of, rhegmatogenous disease within individuals.