The following points highlight the three major nutritional disorders of eye. The nutritional disorders are: 1. Night Blindness 2. Bitot’s Spot 3. Corneal Vascularization.
Nutritional Disorder # 1. Night Blindness:
a. Night blindness is a frequent complaint in underdeveloped communities who have no night lights and where the diet is grossly lacking in retinol and β-carotene. Children who stray from home after dark may get lost, or fall down a well or injure themselves in other ways.
b. Many factors besides retinol deficiency may contribute to complaints of night blindness. These include fatigue, emotional disturbances associated with acute danger and also chronic anxiety states.
c. There are organic causes such as retinitis pigmentosa.
d. Night blindness arising from Vitamin A deficiency always respond to suitable vitamin therapy and it is unwise to make the diagnosis before adequate therapeutic trials have been carried out.
Nutritional Disorder # 2. Bitot’s Spot:
a. Greyish or glistening white plaques formed of desquamated thickened conjunctival epithelium, usually triangular in shape and firmly adherent to the underlying conjunctiva.
b. Sometimes the spots are covered with material resembling dried foam which can be scraped away but forms again. It consists of epithelial debris, fatty globules and often masses of xerosis bacilli. The spots are generally bilateral, on the temporal sides of the cornea, and in coloured races are often surrounded by dense brown pigmentation.
c. Pigmentation of the conjunctiva is frequently associated with exophthalmia. Pigment may be deposited round the cornea (pigmented ring), in the lower eyelid (pigmented gutter), and over the sclera equatorially in the area commonly occupied by Bitot’s spots. Various forms of irritation appear to play a major role in its causations.
Nutritional Disorder # 3. Corneal Vascularization:
a. The essential lesion in this condition is an invasion of the normally avascular cornea by capillary blood vessels. These vessels cannot be seen with the naked eye, nor with an ordinary hand lens.
b. Small greyish-white opacities may also be seen on the surface of the cornea.
c. The patient often complains of a burning sensation in the eyes, misty vision, lachrymation and photophobia the latter symptom may make slit-lamp examination difficult.
d. There is often injection of the conjunctiva with diluted blood vessel which are easily visible on simple inspection.
e. The presence of an injected conjunctiva should not allow the assumption that a vascular cornea is also present.
f. Corneal vascularization may be associated with the orogenital syndrome, with keratomalacia and with ariboflavinosis.
g. Nutritional amblyopia is a major nutritional disorder of the eyes.