Children with yellow-eye in photographs are typically advised to immediately seek evaluation from an optometrist or ophthalmologist, who will assess and diagnose the condition and refer to a vitreo-retinal specialist. Coats disease itself is painless. Pain may occur if fluid is unable to drain from the eye properly, causing the internal pressure to swell, resulting in painful glaucoma. Presentation
Coats usually affects only one eye (unilateral) and occurs predominantly in young males 1/100,000, with the onset of symptoms generally appearing in the first decade of life. Peak age of onset is between 6–8 years of age, but onset can range from 5 months to 71 years.Coats disease results in a gradual loss of vision. Blood leaks from the abnormal vessels into the back of the eye, leaving behind cholesterol deposits and damaging the retina. Coats disease normally progresses slowly. At advanced stages, retinal detachment is likely to occur. Glaucoma, atrophy, and cataracts can also develop secondary to Coats disease. In some cases, removal of the eye may be necessary (enucleation). Coats disease is a rare extramuscular manifestation of facioscapulohumeral muscular dystrophy (FSHD). A single study reported it in 1 percent of FSHD patients, most often those with FSHD type 1 (FSHD1) with large D4Z4 deletions. Pathogenesis
Coats disease is thought to result from breakdown of the blood-retinal barrier in the endothelial cells, resulting in leakage of blood products containing cholesterol crystals and lipid-laden macrophages into the retina and subretinal space. Over time, the accumulation of this proteinaceous exudate thickens the retina, leading to massive, exudative retinal detachment.
When oxygen is breathed at high partial pressures, a hyperoxic condition will rapidly spread, with the most vascularised tissues being most vulnerable. During times of environmental stress, levels of reactive oxygen species can increase dramatically, which can damage cell structures and produce oxidative stress.While all the reaction mechanisms of these species within the body are not yet fully understood, one of the most reactive products of oxidative stress is the hydroxyl radical (·OH), which can initiate a damaging chain reaction of lipid peroxidation in the unsaturated lipids within cell membranes. High concentrations of oxygen also increase the formation of other free radicals, such as nitric oxide, peroxynitrite, and trioxidane, which harm DNA and other biomolecules. Although the body has many antioxidant systems such as glutathione that guard against oxidative stress, these systems are eventually overwhelmed at very high concentrations of free oxygen, and the rate of cell damage exceeds the capacity of the systems that prevent or repair it. Cell damage and cell death then result. Diagnosis
Diagnosis of central nervous system oxygen toxicity in divers prior to seizure is difficult as the symptoms of visual disturbance, ear problems, dizziness, confusion and nausea can be due to many factors common to the underwater environment such as narcosis, congestion and coldness. However, these symptoms may be helpful in diagnosing the first stages of oxygen toxicity in patients undergoing hyperbaric oxygen therapy.