Coats' syndrome is associated with reduced pressure autoregulation in retinal arterioles

Purpose Coats’ disease is a rare condition characterised by dilatation and hyperpermeability of retinal vessels typically affecting one eye, which may lead to severe visual loss. The disease is treated by retinal photocoagulation, but there is a need for a treatment more targeted at the pathogenic mechanisms of the disease, which are presently unknown. Therefore, the purpose of the present study was to study the contribution of disturbed pressure and metabolic autoregulation to the pathogenesis of Coats’ disease. Methods Seven patients, three males and four females aged 34.1, 11–69 years (mean, range) affected by Coats’ disease in one eye were studied in both eyes using the Dynamic Vessel Analyzer (DVA). Video recordings were used to measure the diameter of larger retinal arterioles during rest, during an increase in the arterial blood pressure by lifting a hand weight and during stimulation of retinal metabolism by flickering light. Results The resting diameter of retinal arterioles was non‐significantly larger (mean ± SEM) in the affected eye (133.9 ± 8.3  μ m) than in the unaffected eye (118.2 ± 8.6). The contraction of retinal arterioles during increased blood pressure secondary to isometric exercise was not significantly different from zero in arterioles, neither from the affected (0.1 ± 0.3%) nor from the unaffected (0.2 ± 0.6%) eye (p = 0.93). Conclusions Coats’ disease is accompanied with impaired pressure autoregulation in retinal arterioles, but there is no significant difference between the response in the affected and the non‐affected eye. The pathogenesis of Coats’ disease is due to other factors than diameter autoregulation in the larger retinal arterioles.