Myopia can cause eye diseases by stretching the delicate tissues of the eye. Typically, myopia occurs when the eye grows longer than average (from front to back). This means the lens inside the eye cannot focus light on the retina correctly, causing distant objects to appear out of focus. We can correct this short-sightedness with a pair or glasses or contact lenses. It is also imperative that we monitor your eye health, as eye elongation as a result of myopia is a risk factor certain ocular diseases (e.g. cataract, glaucoma, retinal detachment, macula changes).

Retinal detachment is the most serious myopia eye disease

Retinal detachment is arguably the most serious eye condition associated with myopia. It is a potentially sight-threatening condition that requires urgent medical attention.

As the eye grows longer, the retinal tissue becomes more stretched and thinned out. The result can be a retinal tear, hole or detachment.

Even a small amount of myopia (up to -3 dioptres) can result in a three-fold risk of retinal detachment. At -6 dioptres the risk is 20-times that of the normal (emmetropic) population. By -9 dioptres the risk is over 45-times normal.

Preventing retinal detachment is crucial in preserving vision. This can be done by slowing the progression of myopia during young age and having regular eye tests to monitor their condition during adulthood. The latter is especially important for high myopes, who are at a greater risk of developing glaucoma and may require closer monitoring. These eye tests can involve dilating the pupil to examine the peripheral retina.

Glaucoma

Glaucoma is a progressive disease of the optic nerve head. The prevalence of glaucoma is approximately 2% in the general population, but more common amongst the myopia population (8%).

Reasons for a higher prevalence of glaucoma in the myopia population is thought to be multifactorial:

• Elongated Axial Length: stretched retinal tissue is more susceptible to glaucomatous damage even at normal intraocular pressures.
• Optic Nerve Morphology: myopes often have more structural baseline changes e.g. tilted optic discs with peripapillary atrophy. This can mask glaucomatous change, delaying diagnosis.
• Biomechanical Susceptibility: thinner tissue provide less resistance to intraocular pressure.
• Vascular Factors: altered blood flow at the optic nerve head may further contribute to optic nerve susceptibility to intraocular pressure.
• Diagnostic Challenges: in high myopia, clinical imaging and interpretation can be difficult – resulting in either under- or over-diagnosis.

Glaucoma is well-managed once detected, but there are no early symptoms. It is therefore important to get regular eye tests with your optometrist, with the appropriate retinal and optic nerve imaging.

Cataracts

Cataract is an eye condition which is more prevalent – and tends to occur earlier – in individuals with myopia. The cause is not entirely clear, however research suggests this could be due to biomechanical stress, oxidative imbalance and metabolic disruptions in the myopic eye.

Symptoms of cataract include blurred vision, refractive change (i.e. changes in spectacle prescription), light sensitivity and colour vision changes. Cataracts are easily picked up in routine eye examinations.

Treatment of cataract involves eye surgery. However, people with myopia often have more complications associated with cataract surgery. In particular, they have increased risk of retinal detachment. It can also be harder to calculate the power of the intraocular lens, leading to less accurate results in terms of spectacle independence. So, if you have myopia it is important to choose an experienced specialist for your surgery.

It’s also worth noting that there is clinical evidence that femto-cataract surgery (using a laser to replace some of the manual steps of the procedure) can reduce the risk of retinal detachment.

Macula disease

The macula is the most sensitive part of the central retina inside the eye. It is responsible for all central vision, including the details of reading and facial recognition. Damage to the macula is devastating for eye sight as well as quality of life.

Even moderate myopia increases the risk of macula disease 10- to 40-times.

As with the other eye diseases associated with myopia, regular eye tests are the best defence against vision loss. Any change to your vision should result in prompt attention by your optometrist or specialist.

Preventing eye diseases caused by myopia

Anyone developing myopia should discuss myopia control with their optometrist. Strategies such as atropine eye drops, ortho-k and soft contact lenses are all effective in slowing (with the possibly of even halting) the progression of myopia.

If you are concerned about myopia then talk to our experts. Call The Eye Practice on (02) 9290 1899 or make an appointment online today.