How to Avoid Blindness Caused by High Myopia

“The retina is a thin, light-sensitive layer of tissue found at the back of the eyeball. It functions like a camera film by converting light into nerve signals, which the brain processes as the images you see,” explained Clinical Associate Professor Andrew Tsai , Senior Consultant from the Surgical Retina Department at Singapore National Eye Centre (SNEC), a member of the SingHealth group.

“In people with myopia, their eyeballs become stretched or what eye experts call an increase in axial length. Over time and especially with severe or high myopia of over -6.00 diopters or 600 degrees, the stretching can cause small, painless tears or holes in the retina,” he explained.

When the naturally occurring gel in the eyeball (also known as the vitreous humour) gets behind the tears or holes in the retina (retinal tear), it can push the retina away from the back of the eye.

This form of retinal detachment called rhegmatogenous retinal detachment, is the most commonly seen in patients, said Clin Assoc Prof Tsai.

The incidence of retinal detachment in Singapore is approximately 10 cases per 100,000 people every year.

Retinal detachment most commonly occurs in people over the age of 50, with the highest risk between ages 40 and 70.

Other risk factors for retinal detachment include having:

• Retinal detachment in one eye previously
• Myopia
• Family history of retinal detachment
• Recent eye surgery (e.g. cataract surgery)
• Sustained eye injuries or trauma

Severe myopia tops the list for causing retinal detachment. In fact, those with high myopia are five to six times more likely*¹ to develop retinal detachment than those with low myopia.

High myopia is also associated with a higher risk of glaucoma, a disease that damages the optic nerve and may occur with or without raised eye pressure.

Similarly, risk of myopic macular degeneration and cataract rises sharply with age and increasing myopia.

Floaters and flashes in the eye are usually the initial symptoms for retinal detachment.

“Floaters are dots or lines that you may see moving or floating in your field of vision. New-onset floaters or an increase in floaters are of concern. Flashes are the sensation of flashing lights or lightning streaks in your field of vision.

The appearance of a "curtain" or dark shadow blocking part of or your entire field of vision is another concerning symptom,” explained Clin Assoc Prof Tsai.

Why is retinal detachment an emergency?

Retinal detachment can cause permanent blindness if not treated immediately.

According to Clin Assoc Prof Tsai, if the macula (an area that serves central vision) is still attached, surgery should ideally be performed within 24 to 72 hours to preserve vision. 

"Visual recovery depends on how long the macula has been detached; earlier repair gives better outcomes," he said.

1. Get comprehensive eye exams annually

Eye exams protect eye health. Those with high myopia should go for annual dilated retinal examinations, which is the best way to detect retinal tears early.

While Optical Coherence Tomography (OCT) can help to monitor the macula for myopic degeneration and traction-related complications.

2. Control myopia progression early

For children and young adults, myopia control interventions can slow eyeball elongation. These include:

• Atropine eye drops: Low-dose atropine can effectively slow myopia progression.
  
  
• Specialty contacts: Orthokeratology (Ortho-K) lenses worn overnight or dual-focus soft contact lenses can slow progression.
  
  
• Specialty glasses: Peripheral defocus management spectacle lenses can better slow progression compared to standard lenses.

3. Make lifestyle modifications

• Increase outdoor time: Aim for at least 2 hours of outdoor time daily to reduce progression.
  
  
• Follow the 20-20-20 rule: For every 20 minutes of near work, look at something 20 feet away (6 metres) for 20 seconds.
  
  
• Avoid eye trauma: Use protective sports or workplace eyewear such as safety goggles to protect your eyes.

4. Monitor for symptoms and report vision changes immediately

Consult an ophthalmologist immediately when experiencing vision changes such floaters, flashes of light, or a curtain-like shadow in vision. These can be early signs of retinal tears or detachment.

References:
1. https://pmc.ncbi.nlm.nih.gov/articles/PMC6688422/

Ref: F26

Related articles:
Cataracts: Causes, Symptoms and Treatments

Glaucoma: How to Prevent and Manage

AMD (Age-Related Macular Degeneration): How to Prevent and Treat