<prompt> Which of the following is used as self-tonometer?Diaton palpebral tonometerRebound tonometerPerkins tonometerDynamic contour tonometer  <response>: Ans. b. Rebound tonometer Ref: Shields Textbook of Glaucoma 6e p35: Diagnostic Procedures in Ophthalmology by H. V Neema and Nitin Neema 2100Rebound tonometer is used as self-tonometer.Rebound Tonometerlmpact-Rebound TonometerA new handheld tonometer, the Icare tonometer is able to measure IOP without the use of topical anesthetic.IOP is determined by measuring the force produced by a small plastic probe as it rebounds from the cornea.The rebounded tonometer has been shown to have similar accuracy to the Tono-Pen, and it is comparable with Goldman for lOPs over a reasonable range in adults.The Icare tonometer proven valuable as a screening tool in childrenQ.The ability to evaluate IOP without the use of topical anaesthesia potentially provides the opportunity to monitor IOP at homeQ.TonometersIndentationApplanation Measures amount of deformation of globe Affected by scleral rigidity Example: Schiotz Measures flattening Based on Imbert fick law Two types:- Variable force Goldman - Variable area Maktakov Types of Tonometers Goldmann: Gold standard Perkins: Hand held tonometer Draeger: Portable and counter balanced Pulsair: Non-contact type, sterilization not required Mackay-Marg:- Useful for scarredirregular cornea - Accurate over soft contact less as well Tono-pen: Hand held form of Mackay Marg Pneumatic tonometer: Also useful for scarred or edematous cornea. Maklakov: Variation in applanation surface, constant force rather than constant area application used. Dynamic contour tonometry Pascal:- Based on a totally different principle that by surrounding and matching the contour of a sphere, the pressure on outside equals pressure on inside.- Advantage: Not affected by corneal thickness Diatontonometer: Penlikehandhelddevice, non -contact type. 