The Silent Damage of Methamphetamine: Imaging-Based Findings in the Retina and Retinal Microcirculation

PURPOSE: To evaluate retinal structural parameters and layer-specific microvascular perfusion using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in patients with chronic methamphetamine use disorder. METHODS: This prospective, cross-sectional study included 45 patients with methamphetamine use disorder and 45 age-and sex-matched healthy controls. All participants underwent comprehensive ophthalmologic examination and standardized OCT and OCTA imaging. Central macular thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, and subfoveal choroidal thickness were assessed by OCT. OCTA was used to quantify foveal avascular zone (FAZ) area, vessel density of the superficial and deep capillary plexuses (SCP and DCP), and flow areas of the outer retina and choriocapillaris. Correlations with duration and cumulative methamphetamine exposure were analyzed. RESULTS: Total and superior quadrant RNFL thicknesses were significantly higher in the methamphetamine group(p=0.039 and p=0.030, respectively). Although SCP-VD was lower in the methamphetamine group, this difference did not reach statistical significance(p>0.05). In contrast, DCP-VD was significantly reduced in the methamphetamine group across total, parafoveal, and perifoveal regions(all p<0.001). Choriocapillaris flow area was also significantly lower in methamphetamine users(p=0.001). No clinical signs of retinopathy were observed in the patient group. Total and superior RNFL thicknesses were positively correlated, and outer retinal flow was negatively correlated, with both duration and cumulative methamphetamine exposure(p<0.05). CONCLUSION: Chronic methamphetamine use was associated with reduced DCP vessel density and decreased choriocapillaris flow despite the absence of clinically apparent retinopathy. These findings suggest layer-specific subclinical microvascular alterations detectable by OCTA. Longitudinal studies are needed to determine their progression and clinical relevance.