IOP is most accurately measured by

Answer: b) Applanation tonometer (BASAK 4th ED, P-262)Measurement of IOP:1. Contact Tonometer* Indentation tonometer> When placed on a eye, the plunger together with a present weight, indents the cornea.> The amount of indentation is measured on a scale and the IOP can be calculated> Not accurate since IOP measured is influenced by scleral rigidity> Types# Schiotz (manual)# MacKay-Marg (electronic)* Applanation tonometer> Based on the principle of Imbert-Fick's law> Applanation tonometer measures the IOP by flattening the cornea over a specific area (3.06mm)> More accurate since the pressure values are not influenced by scleral rigidity> Types# Goldmann (slit-lamp mounted)# Parkins' (hand-held)2. Non-Contact tonometer3. Digital tonometry: IOP is roughly assessed by digital palpation, fluctuating the down-turned eye between two index fingers through the upper lid