Which of the following tonometer can be used in diseased cornea

Tonopen can be used in diseased cornea. 1. TONOPEN Principle - force required to keep the flat plate of plunger flushed with sleeve is measured against the pressure of corneal deformation. 2. Schiotz Indentation Tonometry Consists of a footplate that rests on cornea and a freely moving plunger A fixed weight is attached to the plunger that can be subsequently increased. 3. Non- Contact Tonometry - A light beam is reflected into sensor which stops the generation of air & records force at the moment of applanation. - The force divided by the area of applanation is the IOP. 4. Ocular ResponseAnalyser It measures the corneal response to indentation by a rapid air pulse. 5. DYNAMIC CONTOUR TOMOGRAPHY PASCAL The difference in the two is called 'Ocular Pulse Amplitude' (OPA) which is an indirect indicator of choroidal perfusion. 6. Rebound Tonometer No anesthesia is used