The changes seen in accommodation during near reflex are all except:
Ans: D (Dilatation of the pupil) Ref: Kanski Clinical Ophthalmology 6th edition pg no: 803: Parson s Diseases of the eye 22nd edition pg no 58.Explanation:Near reflex is a synkinesis which is activated when the gaze is changed from a distant to a near target.It comprisesAccommodationConvergenceMiosisDuring accommodation, the circular ciliary muscle contractsa the zonules relax a the capsule is relieved of tension athe curvature of the anterior lens capsule increases a the converging effect of the lens is increased a the near object is focused on the retina. The radius of curvature of the anterior lens capsule is decreased from 10 to 6 mm.Near reflex pathway:Impulses from the medial recti muscles while converging - third cranial nerve - mesencephalic nucleus of the trigeminal nerve - presumptive convergence centre in the pretectal or tectal region - Edinger Westphal nucleus a - Third nerve - spincter muscle of the iris.
Increase in curvature of lens
Contraction of ciliary muscle
Convergence of visual axis
Dilatation of the pupil
Accommodation and Its Anomalies