Purpose To assess the effects of subthreshold laser treatment (STLT) for retinal arterial macroaneurysms (RAM) associated with foveal exudative manifestations and visual acuity deterioration.

Methods Patients with RAM associated with foveal exudative manifestations and best-corrected visual acuity (BCVA) worse than 20/80 Snellen equivalent underwent a ophthalmological examination, including ETDRS visual acuity, optical coherence tomography (OCT) and fluorescein angiography. The patients were prospectively observed for 4 months, and in absence of spontaneous improvement, they underwent STLT using an infrared diode laser.

Results Primary outcome measures were a reduction in mean central point thickness (CPT) and BCVA changes at the 12-month examination. Secondary outcomes included changes in mean total macular volume (TMV) and central subfield thickness (CST). Nine patients were enrolled and prospectively followed up. The mean baseline values of BCVA, CPT, TMV and CST were 0.8±0.1 (logMAR±SD), 340±49 μm, 7.14±0.05 mm³ and 366±37 μm, respectively. At the 4-month examination following STLT, the mean BCVA improved to 0.6±0.2, whereas the mean CPT, TMV, and CST decreased to 274±29 μm, 6.87±0.11 mm³ and 296±33 μm. At the 12-month examination, the mean BCVA was 0.36±0.2, the mean CPT was 195±11 μm, the mean TMV was 6.55±0.19 mm³, and the mean CST was 239±14 μm, respectively. No side-effects were noted. In particular, no sign of retinal thinning and underlying backscattering typical of conventional laser treatment could be detected at the site of the laser application on OCT.

Conclusion The current pilot investigation of STLT for the treatment of symptomatic RAM revelas encouraging data. A randomised clinical trial is required to ascertain the real efficacy of this technique and the most appropriate settings to be employed.