This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Retina, Subject name: Ophthalmology
What is the earliest ocular manifestation of pregnancy induced hypeension? 
Select and explain. 
A. Soft Exudates, B. Flame shaped hemorrhages, C. Constriction of nasal blood vessels, D. Papilledema
C: Constriction of nasal blood vessels
Answer: C: Constriction of nasal blood vessels 
Explanation: Fundus changes in Pregnancy Induced Hypeension (Clinical Manifestations in PIH) The clinical course of fundus changes in PIH may be divided into three stages: (i) Spastic stage: Characterised by spasm of retinal aerioles. (ii) The stage of sclerosis: When pregnancy induced hypeensive changes are superimposed on pre-existing organic sclerotic changes in the vessels. (iii) The stage of retinopathy: Characterised by cotton wool spots, micro aneurysms, flame shaped and splinter haemorrhages, hard exudates, disc edema etc. The first change observed in normal retinal aerioles is constriction of the lumen of superior nasal aerioles.