By Dr. Colin Michie
Eyes can catch us unawares. Vision can be stolen slowly, quietly. The most common thief is often glaucoma. About half of those with glaucoma are not aware that they suffer with it.
Glaucoma is an affliction of the retina and optic nerves. It is a global problem. It is the most common cause of blindness in those between 40 and 84 years in Barbados, Trinidad and Tobago. The disease may be more aggressive in the Caribbean: Surveys in Barbados found that it was common, particularly in older men with a family history of the disorder. Black people are between six to eight times more likely to develop glaucoma than white people.
Other factors can be involved. For instance, diabetics are twice as likely to develop glaucoma. Tobacco smoking and alcohol use increase the risks too, a finding publicised this month in a large “Eyes of Africa” study. Some medical disorders such as migraine and obstructive sleep apnoea may contribute to this condition too. Retinae are a particularly sensitive part of our brains, linked to our general health in ways not fully understood.
Glaucoma usually increases fluid pressures inside the eyeball and damages the nerves cells of the retina and optic nerves. Of all our nerve cells, retinal ones need more oxygen than others, particularly in the area we use for most high acuity, accurate vision, the macula. Damage to these leads to a progressive loss of vision. Initially small blind spots appear on the sides of the visual fields – these may not be obvious to a sufferer, but with time, vision can be limited to a narrow tunnel view of the world, or disappear altogether.
Finding and treating glaucoma as early as possible, before the visual fields change, is crucial to preserving vision. Screening for glaucoma is available – this is a painless process. So if you are over 40, particularly if you have a family history of blindness, take action to preserve your vision – have a regular check! By squirting a jet of air onto the surface of the eye, or bouncing a tiny probe off the cornea, the pressure inside the eyeball can be measured.
A new technology assesses the eyes after dilating the pupils – optical coherence tomography (OCT). This uses reflections from a laser to take a three-dimensional photograph of the inside of your eye. OCT can image below the surface, looking at the layers of the retina, or its blood vessels, allowing really accurate assessments of eye structures. Ophthalmologists will check and measure visual fields too. These tests provide important insights – becoming older can be less of a surprise.
A diagnosis of glaucoma may become one of life’s turning points; it comes with many strong emotional and social implications. It can cause anxiety, fear and depression, linked to ruminations about a loss of independence, losses of a capacity to read, go for a walk, or drive. There may be perceived risks of becoming a burden. But glaucoma can be slowed, if diagnosed. Surgeons of the Association of Caribbean Glaucoma who work with Orbis and UWI report that over years, in their practices, early surgery with simple procedures to reduce the pressure inside the eyes means less visual loss for their patients. Surgery aims to drain fluid from the eye safely. Sometimes, this involves using tiny drains, sometimes a laser is used. These are supported with eye-drops to increase eye fluid drainage. Regular checks are then made to measure pressures, the visual fields and a check OCT.
Despite surgery, hard-working nerve cells at the back of the eye will benefit from planned supports from us to work optimally. Valuable lifestyle changes include increasing dietary antioxidants (with fruit and vegetables) omega-3 fatty acids (found in fish or chia seeds) while reducing salt intake. Regular brisk walking or swimming help cardiovascular health and reduce the pressure inside the eyes. Reducing stress levels with breathing exercises or meditation also reduces eyeball pressures.
Many technologies are being explored to improve retinal health. Medicines, nutraceuticals, herbals, stem cells and gene therapies all have potential. Treatments under test and trials include traditional medicines such as gingko biloba, goji berries or medicinal mushrooms; more established agents such as insulin, citicoline or metformin may be beneficial too. Delivery systems using contact lenses or gels sometimes work better than eye-drops.
In practical terms, visual rehabilitation and “eye comfort housing” approaches can already provide good corrections for difficulty reading or walking, or preventing falls. Simple changes such as improved lighting, sunglasses to reduce glare, low tech magnifying devices, contrast markers in the home, digital devices backed by good advice improve the quality of life.
Glaucoma checks are valuable – help build an eye-care culture in your family and local community to make sure everyone has one regularly!
Useful resources: cdc.gov/vision-health/about-eye-disorders/glaucoma.html ~ nhs.uk/conditions/glaucoma
Dr. Colin Michie specializes in paediatrics, nutrition, and immunology. Michie has worked in the UK, southern Africa and Gaza as a paediatrician and educator and was the associate Academic Dean for the American University of the Caribbean Medical School in Sint Maarten.
