Waxy pallor of optic disc is seen in which disease-

Ans. is 'a' i.e., Retinitis pigmentosa Examination findings in retinitis pigmentosao Ophthalmoscopic findings are characteristic and includeRetinal pigmentary changes (Bone spicule intraneural retinal pigmentation) : - Retina studded with small, jet-black spots resembling bone corpuscles with a spidery outline. These pigmentary changes are typically perivascular and retinal veins (never arteries) have a sheath of pigment for part of their course. These changes affect equatorial region initially sparing the posterior pole and periphery. Later in the course of disease whole retina is involved.Attenuated and thread like retinal arterioles and veins.Pale and waxy optic disc (consecutive optic atrophy).Thinning and atrophy of retinal pigment epithelium (RPE) in mid and far peripheral retina with relative sparing of RPE at macula.o Electroretinogram (ERG) and particularly the electro-oculogram (EOG) are markedly subnormal.