First clinical sign of Vitamin-A deficiency is
All the ocular manifestations of Vitamin-A deficiency are collectively known as 'Xerophthalmia' (Dry Eye) –
Xerophthalmia is most common in children aged 1 - 3 years

'First clinical sign' of Vitamin-A deficiency: Conjunctival xerosis
'First clinical symptom' of Vitamin-A deficiency: Night blindness
Conjunctival xerosis in Xerophthalmia has a characteristic appearance of 'emerging like sand banks at receding tide
'Bitot's Spots' are triangular, pearly-white or yellowish, foamy spots on bulbar conjunctiva, on either side of cornea; In young children they indicate Vitamin-A deficiency, whereas in adults they are often inactive sequelae of earlier disease
Night blindness
Conjunctival xerosis
Bitot’s spots
Keratomalacia