Written By Despina
Contributing Optometrist

We have learned in this program that increasing axial length of the eye, caused by the effects of wearing minus lenses, results in increasing myopia. But perhaps the more serious aspect of this increasing axial length are the longer-term sight-threatening consequences associated with it, such as glaucoma, cataract, and retinal detachment.

As far as retinal detachment is concerned, it may be considered the most serious of the three, in that it is a medical emergency and needs urgent attention. Loss of vision can be sudden, unlike other diseases that usually progress more gradually.

Generally, the higher the myopia, the greater the risk or retinal detachment. For a refractive error of -1.00 to -3.00 dioptres, the risk increases four-fold. Between -3.00 and -6.00 diopters the risk increases ten-fold. This is because as the eye elongates, the layers of the eye stretch, making them weaker and more vulnerable to damage. So in a high myope, the retina can detach spontaneously from its underlying layers.

Another important consideration is that  myopes are more vulnerable to retinal detachment after trauma, such as a blow to the eye or head,  and in the presence of lattice degeneration. Lattice degeneration is a disease of the eye where the peripheral retina becomes weak, most probably due to inadequete blood supply, and may develop a tear, break or hole. If fluid from the vitreous chamber leaks through these, the retina may detach very quickly.   

The symptoms of retinal detachment are unmistakable. Early symptoms include the sudden appearance of a large amount of floaters, and flashes of light. If the retina has already begun to detach, a black curtain may be seen descending over the field of vision. In many cases the retina can be reattached by laser, but there will probably be some irreparable damage to the retina and some loss of visual field. The amount of vision lost greatly depends on the time lapsed between the initial symptoms and seeking medical attention, so it is crucial to address any symptoms immediately.