[Analysis of 5-year efficacy of adjuvant external drainage of subretinal fluid therapy in Coats disease with severe exudative retinal detachment].

<b>Objective:</b> To study the 5-year long-term efficacy and complications of adjuvant external drainage of subretinal fluid therapy in patients with severe exudative retinal detachment (ERD) secondary to stage 3B juvenile Coats disease. <b>Methods:</b> This was a retrospective case series study. From January 2014 to December 2018, twenty-three eyes of 23 patients with severe ERD secondary to stage 3B juvenile Coats disease diagnosed at Beijing Tongren Hospital, Capital Medical University were included in this study. All patients underwent wide-field retinal imaging, fluorescein fundus angiography (FFA) and ocular color Doppler imaging. All cases received external drainage of subretinal fluid therapy combined with treatments including intravitreal injection of anti-vescular edothelial growth factor (VEGF) agents, retinal photocoagulation and/or cryotherapy. Clock-hour extent and occlusion of retinal vascular telangiectasia, changes of subretinal fluid, best corrected visual acuity (BCVA, logMAR) and incidences of complications including vitreous fibrosis, subretinal fibrosis, tractional retinal detachment (TRD), retinal cyst and complicated cataract were observed. Statistical analyses were performed using Fisher's exact test, corrected chi-square test and chi-square test, Mann-Whitney <i>U</i> test, paired-sample Wilcoxon signed-rank test and Logistic regression analysis. <b>Results:</b> Among 23 eyes of 23 patients, 22 patients (95.7%) were male and 1 patient (4.3%) was female. All patients had unilateral Coats disease. The median age of initial visit was 43.0 (38.0, 47.0) months (range, 26 to 129 months). The median clock-hour extent of retinal vascular telangiectasia was 9.0 (7.0, 10.0) (range, 5 to 12). The median time of external drainage of subretinal fluid therapy was 1.0 (1.0, 2.0). The median time of retinal photocoagulation was 2.0 (2.0, 3.0). The median time of intravitreal injection of anti-VEGF agents was 4.0 (3.0, 6.0). Retinal cryotherapy was performed in 14 eyes (60.9%). The median follow-up after initial treatment was 66.5 (64.0, 70.0) months (range, 60 to 89 months). At last follow-up, retinal vascular telangiectasia of all patients were completely or partially occluded, and subretinal fluid was completely absorbed or obviously reduced; of which 8 eyes (34.8%) were completely occluded, and 15 eyes (65.2%) were partially occluded. The incidences of vitreous fibrosis, TRD and complicated cataract in the completely occluded eyes were lower than those in the partially occluded eyes (all <i>P</i><0.005). No global enucleation was performed in any patient because of disease progression. Among 15 eyes of 15 patients underwent BCVA examination, 3 eyes had an improved vision, 10 eyes had a stable vision and 2 eyes had a decreased vision. The difference between median BCVA after treatment and that before treatment was not statistically significant [2.6 (2.6, 2.9) <i>vs</i>. 2.9 (2.6, 3.2), <i>Z</i>=-0.14, <i>P</i>=0.891]. Seventeen eyes (73.9%) developed vitreous fibrosis; 21 eyes (91.3%) developed subretinal fibrosis; 12 eyes (52.2%) developed TRD, 5 eyes (21.7%) developed retinal cyst and 15 eyes (65.2%) developed complicated cataract. Patients with complicated cataract had a higher incidence of TRD than that in patients without complicated cataract (11/15 <i>vs.</i> 1/8; <i>χ²</i>=10.96, <i>P</i>=0.001). The occurrence of TRD was associated with the greater clock-hour extent of retinal vascular telangiectasia and the presence of complicated cataract (<i>OR</i>=2.04, 95%<i>CI</i>: 1.14-3.64, <i>P</i>=0.016; <i>OR</i>=73.18, 95%<i>CI</i>: 4.58-1 168.40, <i>P</i>=0.002). <b>Conclusions:</b> External drainage of subretinal fluid is a long-term effective adjuvant therapy in stage 3B juvenile Coats disease with severe ERD. However, there are possible complications such as TRD and complicated cataract after surgeries.