Myopic macular degeneration

Very myopic eyes are exposed to the risk of degenerative processes that can seriously impair vision.

Myopic macular degeneration, in English Myopic Macular Degeneration (MMD), has become one of the most frequent causes of low vision and visual loss in the adult population worldwide, particularly in East and South-East Asia.

According to a study, published in Investigative Ophthalmology & Vision Science, By the team of researchers led by Prof. Mukharram M. Bikbov, director of the Eye Research Institute in Ufa (Russia), the prevalence of myopic macular degeneration at advanced stages (3 and 4) in the very elderly population increases 8.8-fold for every 1 millimetre increase in the length of the ocular axis, with a prevalence of around 75% in individuals aged 85 years and over and a high risk of a marked deterioration of visual function.

In general, eyes with high myopia are at risk of pathological myopia, a condition that leads to permanent degenerative changes, such as:

• Retinal atrophy: due to the abnormal elongation of the eyeball, which makes the retina thinner with the formation of atrophic areas associated with visual loss. Atrophy can affect any area of the retina, but when it occurs in the central part of the macula, it leads to a deterioration of central vision.
• Lacquer cracks: these are linear tears that occur in Bruch's membrane, between the retina and the choroid, and can also appear in the macula. They may also be associated with retinal haemorrhages, with or without choroidal neovascularisation (CNV).
• Choroidal neovascularisation (CNV): are blood neovases that can develop as a result of atrophy or lacker cracks and can involve the macula. Neovases are extremely fragile and have very permeable walls. Their presence can lead to the formation of scar areas and visual loss.
• Retinal detachment: the abnormal elongation of the eyeball and the consequent stretching of the retina increase the risk of retinal detachment from the ocular fundus, the most frequent symptom of which is the sudden onset of bright flashes and sparkles

In the study we mentioned above to examine the prevalence of myopic macular atrophy, an initial sample of 1,526 individuals aged 85 years or older, 25.6% men, from the Russian republic of Bashkortostan were recruited, interviewed at home to collect biographical data and medical history, and summoned to the hospital for medical and ophthalmic examinations. Of those who managed to perform all the protocol checks, individuals with stage 3 (10 patients) and stage 4 (11 patients) myopic macular degeneration had significantly worse corrected visual acuity than participants without MMD.
Among these patients, the prevalence of moderate to severe bilateral low vision was 40% (stage 3) and 64% (stage 4), respectively, while the prevalence of binocular blindness was 20% (stage 3) and 27% (stage 4).
Among individuals with mild myopia, the prevalence of MMD was 0% for right eyes and 2% for left eyes. In the moderately myopic group, the prevalence of MMD increased to 8% (stage 3) and 11% (stage 4), while in the high myopes group it jumped to 78% (stage 3) and 75% (stage 4), respectively.

These results are fundamental to understanding the importance of controlling myopia in children to prevent the onset of retinal diseases in their adult life.

One of the main problems is that most parents are not fully aware of the complications of high myopia, just as they are not fully aware of the possibilities of controlling it in children.

Each one diopter (1 D) increase in myopia over the course of a child's development increases the risk of myopic macular degeneration by 67% and the risk of retinal detachment by 30%, according to data published by Mark Bullimore and colleagues in Optometry & Vision Science. The same authors in a study published in Scientific ReportsThey predicted that by 2050 in the United States between 27% and 43% of uncorrectable low vision cases will be attributable to myopia.

In a 2019 study by Hansen and colleagues on a cohort of 1443 adolescents aged 16-17 years, the prevalence of myopia was 25%, with a doubled risk among those who spent a lot of time using digital devices rather than playing outdoors.

If we want to protect the health of our children's eyes, from an early age let's encourage them to go outdoors whenever possible: it will help them both to avoid the risks of sedentariness and overweight and to ward off dangers to their eyesight!

To answer many parents' questions about their children's eyesight, we point out:

• Children's eyes - Oculista Italiano
• Dysgraphia and visuo-postural defects - Oculist Italiano
• Myopia: a diagram to predict its development - Oculista Italiano

• Bikbov MM, Gilmanshin TR, Kazakbaeva GM, et al. Prevalence of Myopic Maculopathy Among the Very Old: The Ural Very Old Study. Invest Ophthalmol Vis Sci. 2024 Mar 5;65(3):29. doi: 10.1167/iovs.65.3.29. PMID: 38512243; PMCID: PMC10960226.
• Bullimore MA, Brennan NA. Myopia Control: Why Each Diopter Matters. Optom Vis Sci. 2019 Jun;96(6):463-465. doi: 10.1097/OPX.0000000000001367. PMID: 31116165.
• Bullimore, M.A., Brennan, N.A. The underestimated role of myopia in uncorrectable visual impairment in the United States. Sci Rep13, 15283 (2023). https://doi.org/10.1038/s41598-023-42108-y.
• Hansen MH, et al. Low physical activity and higher use of screen devices are associated with myopia at the age of 16-17 years in the CCC2000 Eye Study Acta Ophthalmol. 2019 10.1111/aos.14242.