16/09/2024
CAUSES OF LOW VISION IN ALBINISM
Primarily, melanin is to protect humans from ultraviolet light, it also has other important functions in the development of the retina, the brain and their interconnectivities. When there is a low production of melanin, it results in poor pigmentation and affects vision.
The hypo-secretion of melanin pigmentation results in vision impairment amongst people with albinism. This is known as Oculocutaneous albinism or type 1 albinism and it affects the hair, skin and eye colour, resulting in discolouration of the hair and skin. The melanin pigment absorbs stray light and protects the eyes and skin from ultraviolet light. If the pigmentation of the iris and choroid is lacking, light penetrates directly through the structures of the eye rather than only through the pupil. Loss of pigmentation in albinism results in extreme light sensitivity because the individual has too much light entering the eye and has no way of stopping or controlling the excess stray light already in the eyes
The first sign of albinism in children is the involuntary rhythmic swinging oscillation (movement) of the eyes. This is referred to as ‘nystagmus’, and can occur in many forms leading to a decrease in vision from the rhythmic movement. The resultant effect is that persons with albinism with this diagnosis tend to tilt their heads or eyes to where they achieve their best vision, called the null position.
Research further shows that children with nystagmus may not do well with timed tests that could put them under stress. Medical doctors have however suggested that shutting of one eye with a hand could cause a change in the vision of the viewing eye due to an increase in nystagmus. The other optical impairment amongst people with albinism is strabismus or ‘crossed eye’ symptom. It is usually caused by a loss of binocular vision and reduces depth of optical perception.
