What is progressive myopia?
Progressive myopia is shortsightedness that continues to worsen year after year. This progression can result in severe myopia (also called high myopia) that may be associated with potentially serious side effects.
Progression of myopia usually occurs during childhood but can continue into early adult years. Typically, the worsening shortsightedness is caused by continuing elongation of the eyeball. The underlying cause of this and why some shortsighted individuals develop high myopia and others do not is not fully understood.
All refractive errors of the eye, including myopia, are measured in dioptres (D). The same unit is used to measure the corrective power of prescription glasses and contact lenses. High myopia usually is defined as shortsightedness of -5.00 D or higher indicated on a glasses prescription.
Side effects of progressive myopia
People with progressive myopia are at higher risk of developing certain eye conditions that are associated with the elongation of the eye and stretching of the retina. These include:
Retinal detachment. A recent study revealed that people with progressive myopia have a 10 times greater risk of retinal detachment. This is because elongation of the eye causes stretching and thinning of the retina. This can result in rips in the peripheral retina and detachment of retinal tissue from the underlying layers of the interior of the eye.
Glaucoma. Characterised by elevated pressure in the eye, glaucoma causes damage to the optic nerve and loss of peripheral vision. Symptoms include blurred vision, headaches, halos around lights and difficulty adapting to darkness.
Cataracts. People with progressive and high myopia have a greater risk of cataracts than the general population. Also, cataracts tend to occur earlier in life among individuals with high myopia. Symptoms include blurred vision, halos around lights, glare, and reduced vibrancy of colours.
Myopia control is the term used to describe methods employed to slow or halt the worsening of progressive myopia. These methods include orthokeratology, other specially designed contact lenses, and progressive or bifocal spectacle lenses.
If your child’s shortsightedness is getting worse year after year, schedule an eye test and discuss myopia control options with an optometrist near you.