Coats Disease

Coats disease

Coats disease is characterised by retinal telangiectasias and exudation and is typically diagnosed between ages 8 and 16 years. Most cases are unilateral (95%) and the condition occurs most frequently in males (75%).

Visual acuity may be reduced by several mechanisms, including cystoid macular oedema, exudative retinal detachment and/or neovascular glaucoma.

Symptoms and/or signs may include reduced vision, strabismus and/or leukocoria however some patients are asymptomatic at diagnosis. This reflects the range of clinical presentations possible. Mild cases may show only a few affected (telangiectatic) vessels in the peripheral retina, while advanced cases may show retinal detachment, corneal oedema and/or iris neovascularisation.

OCT imaging typically shows subtle intraretinal edema or subretinal fluid. OCTA and fluorescein angiography show vascular abnormalities (telangiectatic vessels) with bulb-like aneurysms. Capillary dropout and areas of retinal non-perfusion may also be seen.

A staging system for Coats’ disease was developed by Jerry Shields et al. Very briefly, stage 1 is characterised by retinal telangiectasia, stage 2 by the development of extra-foveal and foveal exudation, stage 3 by the development of exudative retinal detachment, stage 4 by the onset of secondary glaucoma and stage 5 is end-stage disease. For further detail, please refer to the Shields et al (2001) paper listed in the references at the bottom of this page.

Case Example

  • Case 1

    A 29 year old Caucasian female with recent onset flashes and floaters, diagnosed with eye disease in her left eye at the age of 13. Her visual acuity in the left eye was counting fingers at 50cm.

    Fundus photograph (left eye)

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    Fundus photograph (left eye)

    The retinal photo shows a large region of pigmented fibrotic material affecting the macula and a large infero-temporal retinal detachment, again with significant associated fibrosis and pigmentation indicating chronicity. There is a sclerosed vessel in the superior retina. On binocular indirect ophthalmoscopy, the fibrotic material was elevated.

    Red-free image (left eye)

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    Red-free image (left eye)

    The red free image shows the sclerotic vessel more clearly.

    Optomap (1), green separation (2) and fundus autofluorescence imaging (3)

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    Optomap (1), green separation (2) and fundus autofluorescence imaging (3)

    Widefield imaging reveals the extent of the infero-temporal retinal detachment. The area of detachment and the macular fibrotic material appear hypo-auotofluorescent on FAF imaging.

    Cirrus OCT Angiography (left eye)

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    Cirrus OCT Angiography (left eye)

    OCTA shows anomalous vessels in the area of macular fibrosis and within the area of the infero-temporal retinal detachment. Areas of capillary dropout and retinal non-perfusion may also be seen.

    Spectralis OCT volume and line scan (left eye)

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    Spectralis OCT volume and line scan (left eye)

    OCT shows the elevated nature of the macular fibrosis. There area of dense pigmentation that corresponds with the peak of the fibrotic material appears hypo-reflective and has cased posterior shadowing. The fibrosis may be seen on OCT as hyper-reflective areas of retinal disorganisation.

    The OCT volume scan shows multiple pigment epithelial detachments, illustrating the exudative nature of this condition, as well as ares of chrorioretinal atrophy.

    Peripheral OCT line scan (left eye, infero-temporal retina)

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    Peripheral OCT line scan (left eye, infero-temporal retina)

Differential diagnosis

Retinopathy of prematurity

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Toxoplasmosis

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Familial exudative retinopathy

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Eales’ Disease

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Retinoblastoma

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References

Shields, J, Shields, CL, Honavar,SG, Demirci,H, Cater,J. (2001) Classification and management of Coats disease: the 2000 Proctor Lecture,American Journal of Ophthalmology, Volume 131, Issue 5, Pages 572-583,

Shields CL, Udyaver S, Dalvin LA, et al (2020) Visual acuity outcomes in Coats disease by classification stage in 160 patients. British Journal of Ophthalmology 104:422-431.

Yousef, YA, Rimawi, AH, Nazzal, RM, Qaroot, AF, AlAref, AH, Mohammad, M et al. (2020). Coats’ disease: characteristics, management, outcome, and scleral external drainage with anterior chamber maintainer for stage 3b disease, Medicine: April 2020 - Volume 99 - Issue 16 - p e19623