XPERT^tm NCT^tm advanced logic pneumotonometer (Reichert) was studied for its reliability and use in glaucoma screening. The evaluated 2400 NCT measurements on 300 eyes were compared to the results of Goldmann applanation tonometry (GAT) from the same eyes. Repeated NCT tonometry had no significant effect on IOP. Local anesthesia reduced mean NCT-GAT difference and standard deviation significantly (p < 0.05),="" i.e.="" feeling="" due="" to="" the="" diminished="" air="" pulse="" force="" provided="" by="" the="" instrument="" had="" still="" considerable="" influence="" on="" iop.="" nct-gat="" regression="" was="" significant="" (p="">< 0.01).="" mean="" iop="" readings="" provided="" by="" nct="" were="" four="" mmhg="" higher="" than="" gat="" values.="" although="" accuracy="" was="" not="" satisfactory="" for="" exact="" measuring,="" it="" was="" satisfactory="" for="" screening.="" the="" results="" suggested="" that="" four="" mmhg="" less="" than="" the="" mean="" iop="" value="" seen="" on="" the="" display="" is="" acceptable="" for="" screening="" when="" the="" difference="" between="" the="" minimal="" and="" maximal="" individual="" readings="" on="" the="" display="" is="" less="" than="" 2sd="" i.e.="" six="" mmhg.="" in="" the="" case="" of="" a="" greater="" difference,="" the="" maximal="" value="" is="" to="" be="" replaced,="" as="" nct="" tends="" to="" read="" higher="" values="" than="">