<prompt> Gonioscopy is useful to see details of which of the following?LensAngle of the anterior chamberIrisCornea  <response>: Ans. b Angle of the anterior chamber Ref Basaks ophthalmology 4th270The purpose of gonioscopy is to identify abnormal angle structures and to estimate width of chamber angle.Direct with goniolenses:Provides direct view of angle.Used for diagnostic operative purposes.Indirect with gonioprisms:Provides mirror image of opp angle.Can be used only under a slit lamp. Normal angle structures seen from anterior to posterior:1. Schwalbes line2. Trabecular meshwork3. Scleral spur4. Ciliary band Grading of the angle Schaffers:GradeAngleGonioscopic ViewClinical interpretationIVWide open 35-45degAll structures seenClosure improbableIIIOpen 20-35degScleral spur seenClosure improbableIIModerately narrow 10-20degTrabecular meshwork seenClosure possibleIExtremely narrow 10degSchwalbes line visibleClosure imminentOCompletely closed 0degNothing visibleClosure present 