Explainer | Why a detached retina is ‘a hot emergency’, the risk of it leaving you blind in one eye and its possible causes, from myopia to riding a roller coaster
- The retina is a layer of sensory cells essential for clear vision. It can detach from the back of the eye for reasons including myopia, age and trauma
- Myopia levels are high among children in East Asia who lack time outdoors and stare at screens too much, and eye doctors are seeing more cases in young patients
My husband’s ophthalmologist described his situation as “a hot emergency”. We both looked at him blankly. So he said it again: A Hot Emergency.
He needed him in the operating theatre that very afternoon.
Having had surgery on his left eye just two months earlier, my husband had presented himself at the ophthalmology department for what was meant to be a routine post-op screening.
The appointment might have been delayed had he not begun to complain of floaters and flashes in the eye, “and a funny sort of veil”.
The hot emergency – 90 minutes on the operating table – was a detached retina.
The retina is a layer of sensory cells at the back of the eye essential for clear central vision and for detecting movement in dark environments. A retinal detachment occurs when this layer becomes separated from the back of the eye, explains Andy Meau, an optometrist and director at Central Eye Care in Hong Kong.
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How serious it is depends on the type of detachment and its location, Meau adds.
The more peripheral retinal detachments do not typically affect central vision. But a large retinal detachment that involves the macula – the part of our retina that is responsible for central vision, most of our colour vision and the fine detail of what we see – would have a significant detrimental effect.
How quickly a retinal detachment is repaired is crucial. Most detachments, says Meau, “occur suddenly and can lead to permanent blindness in a matter of hours or days if left untreated because of sensory cell death. Anyone experiencing sudden onset of flashes or floaters should be evaluated right away”.
The earlier the development of myopia, the higher the likelihood of high myopia as an adult, and thus the higher risk of retinal degeneration
Ageing is the most common cause of retinal detachment. As we age, the vitreous humour – gel-like fluid in the eye – may change in texture and shrink. Sometimes, as it shrinks, it can pull on your retina and tear it.
Meau says other causes of retinal detachment include earlier eye surgery – my husband’s successful previous operation could have contributed to his; trauma, especially in contact sports; activities involving sudden change in velocity, such as skydiving, diving and riding roller coasters; family history, and: existing systemic disease such as diabetes.
The lifetime risk of a detachment in normal eyes is around 1 in 300, but can be as high as 1 in 20 in patients who are very shortsighted. In this condition, also known as nearsightedness or myopia, near objects appear clear, but objects farther away look blurry. For my husband, a slightly myopic sixty-something, the risks were stacked up.
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Highly myopic eyes carry a much larger risk than those with low or no myopia, says Meau, who is seeing a rising number of cases of retinal detachment.
“Myopia increases because of abnormal elongation of the eyeball,” and the higher the degree of myopia the longer the eyeball. This can lead to increased tension on the retina, and thinning, that can trigger certain types of retinal degeneration that may lead to retinal detachment.
The number of people with myopia is growing; the World Health Organization estimates that half of the world population will be myopic by 2050. Meau has been seeing more young patients with retinal degeneration.
Children are starting to develop myopia at an earlier age, Meau says, “especially in Asian cities such as Hong Kong, Singapore, and Taipei”.
“One recent survey revealed that close to 25 per cent of six-year-olds in Hong Kong are myopic, 60 per cent of 12-year-olds, and almost 90 per cent of 18-year-olds.
“The earlier the development of myopia, the higher the likelihood of high myopia as an adult, and thus the higher risk of retinal degeneration,” he says.
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The reasons for this are varied, he says. “Myopia development can be due to lack of outdoor time, family history, extended near vision” or a mix of all three. “There is a lot of focus on treatment with contact lenses, spectacles, eye drops, all designed especially for kids to slow down the deterioration of myopia as they grow,” Meau says.
Because myopia is such a key cause of retinal detachment, Meau strongly recommends that the myopic population have their eyes and retina examined at least once a year “so we can detect any changes in the retina as early as possible”.
The history of retinal detachment correction surgery is one of medicine’s great success stories.
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Descriptions of detachment were recorded as early as 1805. Fairly outlandish treatments were attempted.
These included bandaging both eyes; applying atropine (generally used these days before eye examinations to dilate the pupil, and to relieve eye pain caused by swelling and inflammation), which essentially paralysed the affected eye, and; restricting patients to bed and using a vice of sandbags around their head to prevent any movement.
One doctor even proposed a plaster mould over the eyes.
The first surgery, attempted in 1805, involved puncturing the white of the eye, the sclera, with a knife and draining fluid from the eye. It wasn’t successful.
Later on, cauterisation was tried, as was electrolysis, and injections of irritant substances under the retina. Nothing worked until attention was given to closing retinal breaks.
The first successful retinal detachment surgery was performed in 1920 and only about 1 in 1,000 surgeries worked. Today, 90 per cent of retinal reattachments are successful the first time around; one in 10 patients needs a second operation.
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There are several types of treatment available, which depend on the severity of the detachment and its location.
Some of the most common ones, Meau says, are laser photocoagulation (the resultant scarring allows the retina to reattach firmly to its normal position), pneumatic retinopexy (injecting a bubble of oil or gas into the eye to push the retina back into place) and scleral buckle (attaching a small band around the eyeball to push the wall of the eye towards the retina).
My husband’s left eye sports a bubble of gas for now to hold the retina in place. Sometimes a bubble of silicone oil is introduced instead and, while this is longer lasting and means a patient can fly – they are prohibited from flying for several weeks if gas is used – silicone oil requires a further procedure to drain it, whereas gas disperses with time.
Post-surgical care includes avoiding lifting heavy weights (so the job of emptying the car of grocery bags falls to me for now), sleeping in a position to support the position of the bubble (so not on his back) and generally taking things a bit easier for a couple of weeks.
Vision will be slow to clear and return. In the days immediately following the surgery, there was only darkness. Now he can see colour and shapes, my wagging finger in front of his eye and, he swears, that little bubble holding it all in place.
