<prompt> Bitemoral hemianopia seen in: PGI Nov 2009Optic chiasmal lesionOptic nerve lesionOptic tract lesionOptic radiation lesion  <response>: Ans: AOptic chiasmal lesion Central lesions of chiasmaQ are characterized by bitemporal hemianopiaQ bitemporal hemianopic paralysis of pupillary reflexes . Lateral chiasmal lesionsQ salient features are binasa! hemianopia associated with binasal hemianopic paralysis of the pupillary reflexesQ- Khurana4th290Common Causes of Central Chiasmal Lesion areSuprasellaraneurysms, tumors of pituitary gland, craniopharyngiomaQ, suprasellar meningioma glioma of third ventricle, third ventricular dilation due to obstructive hydrocephalus chronic chiasmal arachnoiditisFig. Lesions of the visual pathways at the level of: 1. Optic nerve; 2. Proximal part of optic nerve; 3. Central Chiasma; 4. Laterla Chiasma both sides: 5. Optic tract; 6. Geniculate body; 7. Part of optic radiations in temporal lobe; 8. Part of optic radiations in parietal lobe; 9. Optic radiations: 10. Visual cortex sparing the macula; 11. Visual cortex, only macula. Type of blindness depending on site of lesion HemianopiaQuadrantic hemianopia SiteCauseTypeHetronvmous hemianopiaHetronvmous hemianopiaHetronyrnous hemianopiaQ Inferior fibres of optic radiationTemporal lobe lesionQSuperior quadrantic hemianopiaQ pie on sky SiteTypeSiteTypeSiteTypeCentral chiasmaBitemporalhemianropiawithbitemporal paralysis of papillary reflexProximal part of optic nerveCL hemianopia All features of optic nerve lesion i.e. complete blindness IL. abolition of direct light reflex IL consensual on CL sideOptictractIncongruous homonymous hemianopia with CL Wernickes reactionSuperior fibres of optic radiationParietallobelesionQInferior qulrantic heminaopiaQ pie on floorLateralgcnicultatcbodyHomonymous hemianopia with sparing of papillary reflex LateralchiasmaBinasal hemianopia Q with hemianopicOpticradiationtotalHomonymous hemianopiad with sparing of papillary reflex no optic atrophyparalysis ofpapillaryreflex AnterioroccipitalcortexCongmous homonymous hemianopia usually sparing macula 