Vitamin A deficiency-
1. Xerophthalmia
2. Phrynoderma / Toad skin - Hyperkeratotic follicular skin lesions
Symptoms of xerophthalmia-
1. Night blindness (nyctalopia)
2. Corneal clouding
3. Corneal xerosis (dryness of the cornea)
4. Conjunctivial xerosis (dryness of the conjunctiva)
WHO classification of Xerophthalmia:
Primary sign:
X1A - Conjuctival xerosis
X1B - Bitot’s spot - On bulbar conjuctiva
X2 - Corneal xerosis
X3A - Corneal ulceration / Keratomalacia (<1/3 surface)
X3B - Corneal ulceration / Keratomalacia (>1/3 surface)
Secoundary sign:
XN - Night blindness
XS - Corneal scar
XF - Fundal changes
NOTE: Xerosis = Dryness
Reference:
1. Harper's illustrated biochemistry, 30th edition (International), P. No. 551
2. Comprehensive ophthalmology, A K Khurana, 7th edition, P. No. 487-88