Structure of the retina The retina is a transparent film only 0.1 to 0.5 mm thick and is the innermost layer of the eye wall, also known as the fundus. The retina is in contact with the vitreous humor on one side and the choroid on the other, like the film in a camera. The thin retina originally has ten layers, the first to the ninth are collectively called the sensory retina, while the tenth is called the retinal pigment epithelium. Of these, the ninth layer of the retina is the most important and is filled with photoreceptor cells. Functions of the retina The basic function of the retina is to convert light into electrical currents that are then transmitted to the brain. When the photoreceptor cells absorb light, the visual pigment containing vitamin A undergoes a structural transformation, creating a chemical effect that causes the photoreceptor cells to emit an electric current. The current passes through more than one million nerve fibers in the retina, converges in the optic nerve and leaves the eye to the brain. The brain receives the message and then analyzes it to produce a meaningful image. Why does the retina detach? Retinal detachment is a pathological condition in which the sensory nerve retina and the retinal pigment epithelium are separated from each other, i.e. there is a gap and fluid accumulation between the ninth and tenth layers of the retina. After retinal detachment, the sensory retina does not receive enough blood and nutrients, and the metabolic wastes are not absorbed. People at risk for retinal detachment People with deep myopia (the deeper the myopia, the greater the risk), retinal tears or peripheral degeneration, posterior vitreous detachment, eye trauma, acute retinal necrosis, cytomegalovirus retinitis, family members with retinal detachment, and cataract surgery with severe complications. Note: If the retinal detachment does not involve the macula, surgery must be performed as soon as possible within 72 hours to preserve visual function; if the retinal detachment exceeds one week, the eye will slowly deflate like a deflated ball, often irreversibly damaging visual function. The chance of retinal detachment is several times higher in patients with deep myopia than in those without myopia. Therefore, patients with deep myopia should avoid strenuous activities, do not overuse their eyes, and reduce intense eye activity. Once a year, dilated eye examinations should be performed, and retinal photocoagulation should be performed promptly if dry retinal holes or degenerative areas are found.