NEET PG-Nystagmus -Ophthalmology скачать в хорошем качестве

NEET PG-Nystagmus -Ophthalmology

To view more videos download our ophthalmology app at https://play.google.com/store/apps/de... Nystagmus:@0:10 → Involuntary oscillatory to and fro movement of the eyes. → Pendular → Phase of equal velocity → Jerk → Phase of unequal velocity → Direction → Direction of fast component, pathological movement is the slow one. → Trajectory → Horizontal, vertical, Rotatory → Conjugate → Both eyes same movement → Null zone → Gaze in which intensity is minimal. Nystagmus Classification:@2:06 1. Physiological • Optokinetic • Vestibular • End – Point 2. Infantile • Congenital • Manifest - Latent 3. Acquired • Gaze evoked • Vestibular • Inter nuclear ophthamoplegia • See- Saw • Down - beat Physiological :@3:04 • → Optokinetic → Looking at moving object • → Vestibular → When cold/ warm saline stimulates endolymph • → End point → Goes to extreme point and comes back • → Specific localizing Nystagmus. Congenital :@3:38 • → Present at birth or appear later shortly • → Usually horizontal, pendular or Jerk • → Abolished in sleep • → Uniplanar → Plane remains unchanged in all gazes. Latent :@4:05 • → Seen only when one eye is covered • → Vision decreases due to nystagmus • →When each eye tested separately improved when both uncovered. Down Beat Nystagmus:@4:42 • → Fast phase down, while eye in primary position of rest. • Pathology: • → Arnold chiari malformation (most important) • → Platybasia Upbeat Nystagmus:@5:17 • → Fast phase up, eyes in primary position of rest • Pathology: • → Cerebellar degeneration (most important)*** • → Multiple Sclerosis • → Brainstorm stroke Vestibular Nystagmus:@5:29 • → Due to vestibular end organ dysfunction. • → Mixed directional, usually horizontal – torsional. • → Suppressed by visual fixation. • →Associated with Vertigo, Tinnitus, deafness. • → Eitology: Labyrinth, Neuritis, Meniere's disease • → COWS: Cold opposite, warm saline • →Cold water when passed into ear stimulates the endolymph & produce nystagmus in same direction. Optokinetic Nystagmus(OKN): • → Image stabilization when viewing a constantly moving visual field. • → Asymmetric OKN is abnormal OKN, when target is moving in one direction compared to opposite. • COGAN’S DICTUM : • →It states that Homonymous hemianopia + Asymmetric OKN (Partial lobe lesion, probably mass lesion) • →Homogenous Hemianopia + Symmetric OKN – Occipital lobe lesion, Vascular lesion.