====== 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 detachmen**t 
  * **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)                                           |

[[https://pubmed.ncbi.nlm.nih.gov/11336931/|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 =====
  - {{ ::sen-2019-coats_disease_an_overview_of_classif.pdf |Coats disease: An overview of classification, management and outcomes.  Indian J Ophthalmolol. 2019 Jun;67(6):763-771}}
  - {{ ::villegas-2014-advanced_coats_disease_treated.pdf |Advanced Coats’ disease treated with intravitreal bevacizumab combined with laser vascular ablation.  Clinical Ophthalmology 2014:8;973-976}}
  - {{ ::shapiro-2011-effects_of_green_diode_laser_in_t.pdf |Effects of Green Diode Laser in the Treatment of Pediatric Coats Disease. Shapiro et al.   Am J Ophthalmolol 2011;151:725-731}}
  - {{ ::current_management_of_coats_disease_2013.pdf |Current Management of Coats Disease, Survey of Ophthalmology 2014;59:30-46}}
  - {{ ::selective_photocoagulation_in_coats_disease-ten_year_follow_up_nucci_2002.pdf |Selective photocoagulation in Coats’ disease: ten-year follow-up. Eur J Ophthalmol 2002;12:501-5}}