There are many conditions that can affect our eyes. It’s wise to get eye problems checked early, just in case.

ACCORDING to the International Agency for the Prevention of Blindness (IAPB), approximately 45 million people worldwide live with blindness, of which 80% or 36 million are over the age of 50.

With the world’s ageing population growing as a result of improved life expectancy, this represents a significant problem as the prevalence of eye diseases such as cataract, glaucoma and age-related macular disorder rise significantly with age.

In a time and age where our older generation should be enjoying the fruits of their labour, they are instead at risk of losing their sight.

World Sight Day

World Sight Day, commemorated annually on the second Thursday of October, is championed by VISION 2020, a global initiative supported by the World Health Organisation (WHO) and the International Agency for the Prevention of Blindness (IAPB). Its objectives are:

·Raise public awareness of blindness & vision impairment as major international public health issues.

·Influence governments/Ministers of Health to participate in and designate funds for national blindness prevention programmes.

·Educate target audiences about blindness prevention, about VISION 2020 and its activities, and to generate support for VISION 2020 programme activities.

In Malaysia

The National Eye Survey conducted in 1996 recorded the prevalence of blindness in Malaysia at 0.29%, with cataract and retinal diseases forming the majority of cases.

Prof Dr Muhaya Hj Mohamad, Chairperson of the Malaysian Medical Association (MMA) Ophthalmological Society, says: “Among those afflicted by blindness, the majority are above 50 years of age because the eye diseases that cause blindness take many years to develop. This is both a blessing and a tragedy €“ a blessing because it can be detected early enough for treatment, and a tragedy for those who never knew that blindness can often be avoided.

“Preserving our sight for as long we possibly can is not as straightforward as it might seem,” she adds.

“Although some cases can be protected and preserved through interventions like corrective glasses, some chronic conditions, such as diabetes, can contribute to blindness as well. So there is no one-stop solution of just seeing an ophthalmologist and getting the problem solved.”

Avoidable blindness

Avoidable blindness is defined as blindness which could be either treated or prevented by known, cost-effective means. Although there are many causes of vision impairment, VISION 2020 is targeting the main causes of avoidable blindness, in order to have the greatest possible impact on vision loss worldwide. These target disease areas are:

Age-related macular degeneration €“ Age-related macular degeneration (AMD) is the most common cause of blindness in industrialised countries, and mainly affects those over 50 years of age. Its prevalence is likely to increase as a consequence of population ageing.

AMD presents in two forms, “wet” and “dry”. In most populations, the dry form is the more frequent, but it is less likely to lead to severe bilateral visual loss.

The wet form is characterised by the development of abnormal new blood vessels deep to the sensory retina, which can leak or bleed, leading to marked loss of central vision; if bilateral, this can be very disabling.

Each year, after the onset of wet age-related macular degeneration in one eye, 15% of persons develop the wet form in their second eye. Current options for prevention are limited, but new treatments are being developed to preserve or restore vision in some patients with the wet form.

Cataract €“ Cataract is defined as the clouding of the lens of the eye, which impedes the passage of light. Although most cases of cataract are related to the ageing process, occasionally children can be born with the condition, or a cataract may develop after eye injuries, inflammation, and some other eye diseases.

Childhood blindness - In low-income countries, high proportions of children are blind from preventable causes, which require community-based interventions. In all regions, children with treatable diseases, principally cataract, can have their sight restored.

Childrens’ eyes cannot, however, be considered smaller versions of adults’ eyes, and specific expertise and equipment are required. Unlike adults, children require long-term follow-up after surgery to manage complications and to prevent amblyopia (“lazy eyes”). The understanding and involvement of parents is critical.

Diabetic retinopathy €“ Diabetic retinopathy is a complication of diabetes mellitus. Well-conducted clinical trials have shown that good control of diabetes and hypertension significantly reduces the risk for diabetic retinopathy, and there is evidence from studies spanning more than 30 years that treatment of established retinopathy can reduce the risk for visual loss by more than 90%.

Screening programmes for detecting diabetic retinopathy at an early stage at which treatment can prevent visual loss and health education programmes are the main means of prevention of blindness due to this condition.

Glaucoma - Glaucoma is a group of conditions characterised by damage to the optic nerve and loss of the field of vision. The two main types are primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG).

POAG is more frequent in whites and Afro-Caribbeans, while PACG is more common in South-East Asia. Glaucoma is uncommon among persons under the age of 40, but the prevalence increases with age.

Other risk factors include raised pressure inside the eye (intraocular pressure), a positive family history and belonging to a susceptible ethnic group.

As the early stages of both types of glaucoma are often asymptomatic, patients often present late, particularly in developing countries. Once vision has been lost, regardless of the type of glaucoma, it cannot be restored.

Low vision - Low vision is currently defined as “visual acuity of less than 6/18 down to and including 3/60 in the better eye”, from all causes. Many such persons require cataract extraction or refraction services. Low-vision services are aimed at people who have residual vision that can be used and enhanced by specific aids.

Onchocerciasis - Onchocerciasis is caused by an infection which is transmitted by the blackfly species. The vast majority of the 37 million infected people live in West, Central and East Africa.

This infection also causes a range of skin diseases and other systemic conditions. The WHO Onchocerciasis Control Programme, which operated between 1974 and 2002, covered 11 countries in West Africa and was highly successful, and it is no longer a public health concern in most of the affected areas.

Refractive errors - Refractive errors (myopia, hypermetropia, astigmatism, presbyopia) result in an unfocused image falling on the retina. The resulting vision impairment often result in lost education and employment opportunities, lower productivity and impaired quality of life.

Assessment of individuals who have refractive errors, particularly those aged 50 years or above, provides an opportunity for identifying other potentially “blinding” conditions before they cause visual loss (such as glaucoma and diabetic retinopathy).

Trachoma - Trachoma, which is the most common infectious cause of blindness, is caused by Chlamydia trachomatis. Children who have the active stages of the disease are the reservoir of infection, while blindness, which occurs after repeated episodes of infection, usually affects adults. Boys and girls are equally affected by active infection, while blindness is more common in women.

Trachoma affects communities that have poor water supplies, sanitation and/or poor health services.

The organism is transmitted from person to person through direct and indirect contact and by flies. Blindness can be prevented by surgery while the infection and its transmission can be reduced with surgery, antibiotics, facial cleanliness and environmental change.

Preserving sight for the future

According to global statistics, as much as 75% of blindness is avoidable through early prevention and diagnosis.

“One of the worst mistakes to make, especially in an ageing person, is to assume that loss of vision is supposed to happen as we grow older,” asserts Prof Dr Muhaya. “This is absolutely untrue. Any change or loss of vision should be investigated because this is our eyesight that we are trying to preserve. Ignoring vision loss is like ignoring chest pain. Just because loss of vision is not fatal doesn’t mean that it’s less important.”

Suggestions for good eye health include the following:

·Visit an ophthalmologist every other year for an eye screening if you are below 40 years old. An annual check-up is recommended for people above 40 years old, have a family history of eye conditions like glaucoma, cataracts or diabetic.

·See a doctor immediately if you have any acute or prolonged episodes like blurred vision, flashes of light, blind spots or any other symptom that affects your vision.

Contact lens users

For those who use contact lenses, there are steps to take to reduce the risk of infections. These include:

• Wash your hands before handling contact lenses
• Follow directions for cleaning and storing contact lenses
• Clean the lens case after each use
• Follow the recommended lens replacement schedule
• Avoid sleeping and swimming in lenses or wearing them longer than recommended
• Maintain better control of blood sugar levels to slow the onset and progression of diabetic retinopathy.

Spotlight on AREDS

The Age-Related Eye Disease Study (AREDS) was conducted by the US National Eye Institute to determine the role, if any, of antioxidant supplements in reducing the rate of progression from intermediate age-related macular degeneration (AMD) to advanced AMD.

This is based on the assumption that the antioxidants can prevent cellular damage in the retina by eliminating free radicals and harmful oxidants that are generated by the eye’s absorption of light and other normal metabolic processes.

The composition of antioxidants and minerals used in AREDS were:

• Vitamin C, 500mg
• Vitamin E, 400 IU
• Beta carotene, 15mg (equivalent to Vitamin A, 25,000 IU)
• Zinc (as zinc oxide), 80mg
• Copper (as cupric oxide), 2mg

This combination, taken daily, was effective in reducing the risk of developing advanced AMD by 25% in patients with intermediate AMD in one or both eyes, and in patients with advanced AMD in one eye only, or vision loss due to AMD in one eye.

AREDS was conducted among 4,757 men and women aged 50 to 80 years, with five years of follow-up. Researchers also cited no significant adverse effects, although individuals who smoke or are exposed to asbestos are not advised to consume high levels of betacarotene.

References:

1. American Academy of Ophthalmology, www.aao.org

2. National Eye Institute, US National Institutes of Health, www.nei.nih.gov

3. National Eye Survey 1996

4. WebMD Eye Health Centre, www.webMD.com

5. Vision 2020, www.v2020.org