Clinical Characteristics and Progression of Pachychoroid Macular Atrophy in Central Serous Chorioretinopathy.

Purpose Macular atrophy is a late-stage complication often associated with age-related macular degeneration (AMD). However, it can also occur in pachychoroid diseases, including central serous chorioretinopathy (CSCR), called pachychoroid macular atrophy (pMA). This study aimed to investigate the characteristics and progression of pMA in CSCR.Design Multicentre retrospective study as part of the Macula society International CSCR Research Network - MICRoN PARTICIPANTS: 38 eyes of 32 patients.Methods Demographic and imaging data were collected. OCT and FAF images were analyzed to identify pMA features, including cRORA, pachychoroid phenotype, and baseline CSCR characteristics. The study comprised two parts: (1) progression analysis, comparing time to pMA among OCT features in cases without baseline pMA, and (2) follow-up analysis, including patients with at least a 12-month interval between two visits showing pMA progression. pMA area, number, and location were manually measured using the HEYEX-2 platform and ImageJ.Main Outcome Measures Progression analysis : OCT features that contributed to faster development of pMA. Follow up analysis - Progression rate of pMA after square root transformation and features that contribute to faster progression in lesion size.Results Among 1675 eyes with CSCR, The prevalence of pMA was 2.27% and the incidence of pMA was 0.89%. Eyes with intraretinal fluid (IRF) experienced faster time to development of pMA (31.34 ± 16.66 months) compared to those without IRF (64.13 ± 37.14 months) (p = 0.039). The mean pMA area increased from 1.65 ± 2.09 mm2 to 3.08 ± 3.14 mm2, with a mean progression rate of 0.29 ± 0.28 mm2/year. Central pMA exhibited a faster progression rate than non-central pMA(0.13 ± 0.078 mm2/year vs. 0.052 ± 0.055 mm2/year, p = 0.011). Larger baseline pMA area was significantly associated with quicker progression (r= 0.65, p = <0.001). However, after square root transformation of pMA area, no significant association with baseline area was found. We also found that central pMA was significantly correlated with quicker progression of pMA area (SQRT) (b = 0.068, p = 0.043). There was significant reduction of central macular thickness (195.72 ± 96.58 to 153.64 ± 100.25 microns, p=0.034) and subfoveal choroidal thickness (372.92 ± 83.84 to 342.8 ± 78.33 microns, p-value =0.029) at follow up.Conclusion PMA in CSCR exhibits distinct characteristics compared to AMD-related GA from established literature. It progresses at a slower rate, and larger lesions tend to advance more rapidly. Additionally, central pMA progresses faster than non-central pMA. The presence of intraretinal fluid during the disease course accelerates the progression of CSCR to pMA.