The struggle in the dark: Navigating night blindness

Navigating through a dark room can be a challenge when even the slightest shift in light makes everything appear blurry. For some, this experience happens even in dimly lit places or as night falls, affecting their ability to see clearly.

Night blindness, or nyctalopia, is the inability to see well in low light conditions, often signalling an underlying issue with the eyes or other health problems.

According to Odhiambo Ohito, the Senior Ophthalmic Clinical Officer (OCO) and Cataract Surgeon at City Eye Hospital in Nairobi, “Nyctalopia is a symptom rather than a disease. It is a warning sign that something is affecting your vision, particularly the ability of the eye to adapt to darkness.”

The World Health Organisation (WHO) indicates that night blindness affects 1.5 per cent of the global population, with higher prevalence in regions with significant vitamin A deficiency. In Kenya, vitamin A deficiency is a leading cause of nyctalopia, particularly among children under five and pregnant women.

According to the WHO, about 30 per cent of Kenyan children under five are at risk of vitamin A deficiency, which increases the incidence of night blindness in these populations.

Ohito points out, “In areas where there is food insecurity, we see higher rates of vitamin A deficiency. Malnutrition is a major issue that contributes to the prevalence of night blindness.”

Nyctalopia occurs when the retina’s rod cells responsible for night vision are compromised. Ohito explains, “When the retina is damaged, whether by disease or nutritional deficiency, it can affect the cells responsible for night vision leading to difficulty seeing in low light.”

Common causes of nyctalopia include vitamin A deficiency, which plays a crucial role in producing rhodopsin, a pigment essential for seeing in low light. “Inadequate vitamin A intake, especially in children, can be the root cause of nyctalopia,” Ohito says.

Retinitis Pigmentosa (RP), a genetic disorder, causes the progressive breakdown of rod cells, while cataracts (clouding of the eye’s lens), glaucoma (damage of the optic nerve), diabetic retinopathy (damage to retinal blood vessels), congenital disorders such as Leber congenital amaurosis and severe myopia (near-sightedness) also contribute to the condition. Some medications, like isotretinoin used for acne, can cause temporary nyctalopia.

The most common sign of nyctalopia is difficulty seeing or navigating in dimly lit environments. Those with nyctalopia may find themselves stumbling or having accidents more often in low-light conditions, as their vision struggles to adjust to the surroundings. In children, this condition can manifest as a reluctance to play outside during dusk or in darkened rooms, as they instinctively avoid situations where they can’t see well.

Several factors can increase the likelihood of developing nyctalopia. One of the main risk factors is nutritional deficiencies, particularly a lack of vitamin A, which is essential for maintaining healthy vision.

Genetic predisposition also plays a role, especially for individuals with a family history of retinal degenerative diseases like retinitis pigmentosa. Chronic diseases, such as diabetes and glaucoma, can also heighten the risk of developing nyctalopia, as these conditions can cause damage to the retina over time. Aging is another factor, as cataracts and other age-related eye problems can lead to difficulties seeing in low light. Additionally, prolonged exposure to UV light can cause retinal and lens damage, worsening the symptoms of nyctalopia.

Addressing the underlying cause of nyctalopia is key to managing the condition. For example, if the cause is a vitamin A deficiency, supplementation can effectively reverse the symptoms.

Cataract surgery, where the clouded lens is replaced with an artificial one, can help restore vision. Managing systemic conditions like diabetes and glaucoma is also important to prevent further damage to the retina. In more severe cases, assistive devices, such as night vision aids, can help individuals cope with the condition.

As Ohito advises, “In many cases, treating the underlying disease, like controlling diabetes or getting cataract surgery, can improve a patient’s vision.”

Prevention of nyctalopia involves early intervention and addressing the causes before they become more serious.

Nyctalopia is a major public health concern in many low- and middle-income countries, where vitamin A deficiency remains prevalent. Public education campaigns on the importance of proper nutrition and early eye exams can reduce the burden of this condition. Additionally, research into genetic disorders like retinitis pigmentosa and emerging treatments can benefit those affected by nyctalopia.

“We must focus on awareness, early diagnosis and treatment to improve quality of life for those affected by nyctalopia,” Ohito says.

Nyctalopia may be a sign of an underlying issue, but with the right approach, it is a manageable condition. According to a research from the American Academy of Ophthalmology early detection and treatment of underlying causes can significantly improve outcomes for patients with acquired night blindness. This can go a long way in restoring vision and improving a person’s ability to navigate the world.