Adult-onset myopia (developing after 20 years of age) can progress over time, though youth-onset (before 20 years) generally shows more aggressive progression which continues until the eye stops growing. Typical sufferers are highly dependent on high-powered glasses or contact lenses and require frequent replacements as the condition escalates.
Myopia usually appears in childhood. The condition does run in families with parents having myopia being the strongest risk factor for myopia; however, some children are becoming short-sighted even though their parents have no distance vision problems. Genetics are therefore not the only contributing factor.
All levels of myopia increase the chance of blinding conditions such as retinal detachment, cataracts, glaucoma and myopia retinal degeneration later in life.
This risk escalates as the level of myopia increases. Myopic maculopathy, a progressive condition causing holes in the retina due to overstretching, is the fourth most common cause of permanent visual impairment in the UK, ahead of diabetic eye disease.
Studies show the risk factor for eye disease due to myopia is comparable to the risk of cardiovascular disease due to untreated high blood pressure. The risk for glaucoma and cataract due to myopia compares to the risk of stroke from smoking over 20 cigarettes per day. For retinal detachment and myopic maculopathy, myopia carries a risk far more than any identified population risk factor for cardiovascular disease. Given that higher levels of myopia entail a higher risk of these conditions, halting this progression can broadly prevent a significant level of blindness.
A chart showing the increased risk of different eye disease with higher levels of short-sightedness. Courtesy of the OSO