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Coats' Disease

Background

  • Described by Georges Coats (Scotland) in 1908
  • Unilateral retinal vascular abnormalities and retinal exudation in young males
  • Similar to Leber's descripiton of a similar condition in 1912 called Leber's disease

Clinical Features

  • Idiopathic retinal telangiectasia
  • Intraretinal and/or subretinal exudation leading to retinal detachment
  • Peripheral retinal nonperfusion
  • Vitreous relatively normal
  • Sporadic
  • No systemic abnormalities
  • Unilateral (if bilateral second eye is very mildly affected)
  • Male in first or second decade of life
  • Xanthocoria

Differential Diagnosis

  • Retinal tumors
    • hemangioblastoma
    • retinoblastoma
    • choroidal hemangioma
  • Exudative vitreoretinopathies
    • Retinopathy of Prematuity
    • Familial Exudative Vitreoretinopathy
    • Norrie disease
  • Other causes of leukocoria
    • retinal hemorrhage
    • toxocariasis
    • persistent fetal vasculature
    • coloboma
    • endophthalmitis
    • CMV retinitis
    • toxoplasmosis

Classification

Stage Fundus Features
1 Retinal telangiectasia only
2 Telangiectasia and Exudation
A Extrafoveal exudation
B Foveal exudation
3 Exudative Retinal Detachment
A Subtotal detachment
A1 Extrafoveal
A2 Foveal
B Total retinal detachment
4 Total retinal detachment and glacuoma
5 Advanced end-stage disease (phthisis with pain

Adapted from Shields JA, Shields CL, Honavar S, Demirci H. Classification and management of Coats disease: The 2000 Proctor Lecture. Am J Ophthalmol 2001;131:572-83

Laser Treatment

  • Diode 532nm recommended by Shapiro et al.
    • Power generally 400 to 750 mW
    • Duration 1000 ms
    • Rapid interval cycles to simulate near continuous treatment
    • endpoint: telangiectatic vessel whitening
  • Diode 810nm recommended by Villegas et al.
    • Large (1.2 mm) spot size
    • Power typically around 350 mW
    • treat entire surface of telangiectatic vessels and/or exudative detachment as well as the avascular retina.
    • endpoint: complete whitening of the telangiectatic vessels
    • add bevacizumab 1.25 mg

Anti-VEGF Treatment

  • adjunctive treatment
  • 1.25 mg via pars plana

References

  1. Sen et al. Coats disease: An overview of classification, management and outcomes. Indian J Ophthalmolol. 2019 Jun;67(6):763-771
  2. Villegas et al. Advanced Coats’ disease treated with intravitreal bevacizumab combined with laser vascular ablation. Clinical Ophthalmology 2014:8;973-976
  3. Shapiro et al. Effects of Green Diode Laser in the Treatment of Pediatric Coats Disease. Am J Ophthalmolol 2011;151:725-731