Coats’ disease: An Indian perspective

Retrospective chart of patients diagnosed with Coats’ disease between from a single referral in India. Two with mean age of 15.67 months-80 vision (77%), unilateral a ﬀ ection (90%) and male preponderance (83.4%) were chief presenting features. Anterior segment involvement was seen in 67 (21.8%) eyes. Retinal telangiectasia were seen in 302 (99%) eyes, exudation in 274 (89%) eyes and retinal detachment in 158 (51.5%) eyes. Four-quadrant disease was seen in 207 (67.2 %) eyes. Visual acuity was (cid:5) 20/200 in 249 (80.9%) eyes. One hundred and nine of 176 treated eyes (61.93%) had favorable anatomical outcome; 207 of 280 eyes (74%) had an optimal structural outcome. Seventeen (5.3%) eyes were enucleated. Complications following treatment included phthisis bulbi (7%), neovascular glaucoma (5%), epiretinal membrane (4.4%) and rubeosis iridis (4.4%). Conclusion: Indian patients with Coats’ disease have a high male predominance, the majority of whom present with severe visual impairment and extensive four-quadrant exudation. Unusual presentations such as pain, vitreous hemorrhage and a high incidence of anterior segment involvement are distinctive to Indian eyes.

cholesterolosis and other posterior segment complications was determined. Fundus photography and fl uorescein angiography were done, whenever indicated and feasible. Imaging with ultrasound and computed tomography (CT) scan were primarily performed to exclude retinoblastoma or where media haze precluded fundal view. Management options included observation alone, laser photocoagulation, cryotherapy, scleral buckling, vitreous surgery, external subretinal fl uid drainage and enucleation. Optimal structural outcome was defi ned as cessation of telangiectatic activity with preservation of globe shape without neovascular glaucoma. Favorable structural outcome was defi ned as an att ached retina besides the features of an optimal structural outcome. Favorable functional outcome was defi ned as improved vision, bett er than counting fi ngers. Histopathologic examination was done in all enucleated eyes for a tissue-based diagnosis. Cytopathologic and biochemical confirmation of subretinal fl uid obtained aft er the external drainage procedure was done. Statistical analysis was done using Univariate and Multivariate analysis for factors predicting a favorable structural and functional outcome. Parametric test of signifi cance (paired t test) was used for continuous data while non-parametric test (Kruskal Wallis test) was used for non-parametric data. The SPSS Version 9 (SPSS Inc, Chicago, USA) was used for analysis.

Results
Over the last 10 years, 280 patients were diagnosed with Coats' disease. The mean age at presentation was 15.67 ϩ 11.6 years (range: Four months to 80 years) with a median age of 11 years. Of the 280 patients, 251 (90%) cases were unilateral and 28 (10%) were bilateral. Males constituted a majority; 256 eyes (83.4%) belonged to male patients, while 51 (17.2%) eyes were that of females. The average duration of complaints was 4.2 months (Range: Four days to six years). The most common clinical symptom at presentation was decrease in visual acuity, seen in 221 (77%) eyes followed by ocular deviation in 69 (22.4%) eyes, pupillary white refl ex (leucocoria) in 62 (20.6%) eyes and ocular pain in nine (2.9%) eyes while fi ve (1.6%) eyes were asymptomatic. The distribution of visual acuity recorded at presentation was thus: 20/40 or bett er in 42 (13.6%) eyes, less than 20/40 and bett er than 20/120 in 17 (5.5%) eyes, less than 120 and bett er than 20/2000 in 62 (20.1%) eyes and 186 (60.8%) eyes had hand motion to nil perception of light.
All eyes were graded according to the stage of the disease at time of diagnosis [ Table 1]. Of the 67 eyes (22%) with anterior segment fi ndings [ Table 2], raised intraocular pressure (Ͼ21 mmHg, Goldmann applanation) was noted in 19 eyes (6%). Retinal telangiectasia were seen in 302 eyes (99%).
Ultrasound scan was done in 70 eyes (22.7%) while fl uorescein angiography was done in 128 eyes (41.5%). A CT scan was required as an additional investigation in four eyes (1.2%) to rule out retinoblastoma. Cytopathologic and biochemical evaluation of the subretinal fl uid in 34 eyes (11%) was consistent with the diagnosis of Coats' disease. Eosinophilic foamy histiocytes with cholesterol crystals were typically seen in all 34 samples.
Observation was adjudged appropriate in 163 eyes (53%) while 103 (33.3%) eyes underwent laser photocoagulation. [17] Thirty eyes (9.8%) underwent scleral buckling, 13 eyes (4.2%) had vitrectomy and 24 eyes (7.8%) were treated with cryotherapy. [18][19][20][21] Twenty-one eyes (6.8%) with advanced disease underwent external drainage of sub-retinal fl uid. [22] Seventeen (5.3%) eyes underwent enucleation while three patients did not undergo treatment. The outcome of management in the 289 eyes that had a follow-up is shown in Table 3.   In the analysis of structural outcome, we analyzed patients with at least 12 months of follow-up from presentation. Among those meeting this criterion, 116 eyes (93 patients) were found to have an average follow-up of 14.2 months (range 12-44 months). Univariate analysis [ Table 4a] of factors responsible for an att ached posterior pole retina at last visit showed att ached retina at fi rst visit, treatment with scleral buckling and peripheral disease to be statistically signifi cantly associated with detached retina at last visit and a correspondingly poor visual outcome. Multivariate analysis [ Table 4b] showed even more signifi cance of these factors in the fi nal retinal outcome; retina status at fi rst visit (P ϭ 0.008), peripheral disease (P ϭ 0.024) and treatment with scleral buckling (P ϭ 0.028).

Complications following treatment included: Phthisis bulbi in
The visual acuity in the eyes with one-year follow-up did not show any signifi cant change in the fi nal visual acuity (mean logMAR 1. 74 baseline and 1.75 at last visit in 116 eyes) P ϭ 0.794, paired t test. Also, there was no statistical diff erence between the baseline and fi nal visual acuity according to quadrantic disease distribution [ Fig. 1].

Discussion
The hallmark lesion of this disease is idiopathic retinal telangiectasia which shows up as 'light bulb appearance' on fl uorescein angiography [ Fig. 2]. Other features of this disease include irregular retinal vessel dilatations, retinal vessel tortuosity, areas of capillary non-perfusion, intra-and/or subretinal exudation and retinal detachment [ Fig. 3]. Macular exudation may be caused by macular telangiectasia [Fig. 4      In order to unravel possible diff erences in the disease manifestation as seen in this part of the world to that reported in the predominantly Western literature available, we compared our findings with several other studies, particularly the one by Shields et al. [7] Anterior segment abnormalities in Coats' disease have been infrequently reported. The incidence of cataract and rubeosis iridis was 8% each in the studies by Shields et al., [7] as compared to 5.5% each in our study. Amongst posterior segment fi ndings, a larger percentage of eyes in our study had more than one-quadrant exudation (91.6% versus 73%) or even fourquadrant exudation (67.2% versus 55%) at presentation. However, exudative retinal detachment (50% versus 80%) and retinal macrocysts (4% versus 11%) were seen much less oft en. We found a bimodal patt ern of onset, 31 patients (11%) being more than 35 years of age at presentation with mean age being 46.72 years (range 35 to 80 years). Male predominance (74.19%) and bilaterality of disease (6.46%) were less marked than the overall group. The adult-onset disease is more localized, slowly progressive and amenable to treatment with a greatly reduced incidence of neovascular complications. [23,24] Nucci et al. have reported anatomical benefi ts from treatment with a yellow-dye laser. [25] We have not seen any patient with   Of the 15 eyes of preschool children (Ͻfour years) in our study, nine eyes had retinal detachment, while seven eyes had exudation Ͼthree quadrants. Stage 3A1 or greater in younger children usually has a poor prognosis. [7,13] Twenty-one eyes with advanced Coats' disease were managed with external subretinal fl uid drainage and cryo therapy. Retinal reattachment was achieved in 57% eyes while anatomical stabilization was achieved in 85.7% eyes (mean follow-up: 15 months).
We compared the causes of poor visual outcome in the treated eyes with those reported by Shields et al. [13] and found that subfoveal fl uid (21.8% versus 47%), subfoveal fi brosis (26.4% versus 29%) and foveal exudation (16.95 versus 11%) were the three commonest causes in both the studies, albeit with some variations. The incidence of epiretinal membrane (4.4% versus 2.5%) and macular edema (11% versus 7.5%) was comparatively higher in our study. In the final outcomes, anatomical stabilization achieved was comparable (74% versus 76%) while 40% patients in the present study as compared to the 20% reported in the quoted study had a fi nal visual acuity of more than 20/200. Seventeen (5.3%) eyes were eventually enucleated in this series, whereas 20 (16%) eyes had to be removed in the quoted study.
On an average, Indian patients present at least fi ve years later than their Western counterparts (mean age: 16.5 years versus 11 years) with an average duration of symptoms of 2.5 ϩ 2.8 years. While more than half (55.5% versus 43%) the patients present with diminution of vision, a large majority (80.9% versus 76%) had visual acuity worse than 20/200. Male predominance is even more pronounced (83.2% versus 76%). Bilateral disease is seen twice (10% versus 5%) more commonly. There appears to be a bimodal presentation, the fi rst major peak at a mean age of 16.5 years and the second smaller peak at a mean age of 46.7 years. Anterior segment involvement is more than twice (21.8% versus 10%) more common. Macular telangiectasia is seen five times (5.5% versus 1%) more commonly. Vitreous hemorrhage is a peculiar presenting feature. Almost half (49.2%) the eyes had retinal detachment at presentation, while more than three-fourths of eyes (78.3%) had disease involvement of three quadrants of fundus or more. Extensive four-quadrant retinal exudation is also seen more frequently (67.2% versus 55%). However, exudative (secondary) retinal detachment and retinal macrocysts are seen much less oft en. Unusual presentations such as pain, vitreous hemorrhage and increased incidence of anterior segment involvement are peculiar to Indian eyes. Treatment in the early stages is oft en successful in achieving anatomical stabilization. However, advanced cases are diffi cult to treat and results are disappointing. Visual improvement in classic Coats' disease of childhood onset is usually very minimal and frequently, complications may compromise visual function despite an att ached retina.