Visual impairment is associated with vision and visual-field loss, where sight function is limited. The World Health Organization estimates that globally, there are about 285 million people with visual impairment.
Of these, 246 million have low vision and 39 million are blind. About 90% of those with low vision and blindness live in developing countries.
Today, on World Sight Day, it is timely to learn more about low vision, which differs significantly from the more common and comparatively innocuous conditions of long- and short-sightedness.
Indeed, many people with low vision dismiss their impairment as “not seeing very well”, while some believe the loss of visual acuity is simply something that happens naturally with advancing age.
Unfortunately, low vision is attributable to eye disorders or underlying conditions such as diabetes, and is not correctable with standard glasses, contact lenses, medicine or surgery.
The most common causes of blindness and low vision among adults are cataract, refractive errors, glaucoma, diabetic retinopathy, and age-related macular degeneration. Some of these are preventable if detected early.
Children, on the other hand, adapt more easily. The most common causes of low vision and blindness in youngsters are uncorrected refractive errors and retinopathy of prematurity (ROP), caused by the abnormal development of retinal blood vessels in premature infants.
Uncorrected refractive errors can result in amblyopia, also known as lazy eyes, which in turn can affect their education. Routine school screenings and prescription of corrective eyewear can prevent this.
Every child born premature needs to be screened for ROP, as early detection will aid in the best treatment and development of the child’s sight.
A low-vision examination is different from those routinely performed by primary-care optometrists and ophthalmologists. The goal of a low-vision examination includes assessing functional needs, limitations of vision, assessing ocular disease, and prescribing low-vision rehabilitation (LVR).
Low vision interferes with a person’s ability to perform daily activities. Furthermore, studies show that adults with low vision and blindness are more likely to succumb to depression.
As such, LVR is aimed at restoring functional ability, and improving the quality of life and independence of low-vision patients.
Rehabilitation is tailored to correspond to the specific visual disability as well as an individual’s expectations, and places emphasis on the vision required for everyday activities such as walking, reading, cooking, sewing, studying and travelling.
Awareness, counselling and education on low vision are important so that those with the condition, as well as their family members and care providers, are able to cope and be equipped with best management practices.
This article was written by Vinodhini Munikrishnayya from EYE2U Consultancy, one of the few low-vision rehabilitation centres in Malaysia. For more information, contact EYE2U at 011-35202812.