ABSTRACT

Thenormal,healthyeyeisinconstantmotion,evenwhenthesubjectisnot followingamovingobjectorlookingfromplacetoplace.Hemaybe holdinghisgazeassteadyaspossible,butverysmalleyemovementscan stillbedetectedbyasufficientlypreciseinstrument.Earlymeasurementsof thesesmalleyemovementswereobtainedbyseveralinvestigators,including Ditchburn[1]attheUniversityofReadinginEngland,Riggs[2]atBrown University,andYarbus[3]inRussia.Theirbeliefintheimportanceof suchdatacanbeinferredfromthedifficult(andsometimeshazardous) techniquesinvolvedinthesepioneeringexperiments:allthreegroupsused amechanicaldevicerigidlyattachedtothesubject'seyebyasuctioncupor alarge,tight-fittingcontactlens.Ausefulentreeintotheearlyliterature onthistopicisDitchburn'sbook[1].Morerecentstudieshavehadthe benefitofnoncontactmethodsofmeasuringeyemovements,asdescribed intheprecedingchapter.