·AIM:Toobtainwideningofapotentiallyoccludableangle,inaccordingtoKanski’sindications,throughpreventiveNd:Yaglaseriridotomy.Theobservationalstudywasperformedbyusinggonioscopyfortheselectionandfollow-upof1165treatedeyesandexploitingShaffer-Etiennegonioscopicclassificationasaquality/quantitytestoftheanglerecession.·METHODS:BetweenSeptember2000andJuly2012,586patientswereselectedattheOutpatients’OphthalmologicalClinicofthePoliclinicoUmbertoIofRomeinordertoundergoNd:Yaglaseriridotomy.AGoldmanntypecontactlens,Q-switchedmode,2-3defocus,and7-9mJintensitywith2-3impulsedischargeswereusedforsurgery.·RESULTS:Fromasearlyasthefirstweek,awhole360°anglewideningwereevidentinthepatients,thusshowingthesuccessofNd:Yaglaseriridotomyinsolvingrelativepupilblock.Theangleremainednarrowby270°in14eyesonly,despiterepetitionsoffurthertreatmentwithlaseriridotomyinadifferentpartoftheiris,twicein10eyesandthreetimesin4eyes.·CONCLUSION:Nd:YaglaseriridotomyrevealeditselfasbeingasafeandeffectivetreatmentinwideningthosecriticalShaffer-Etiennegrade1and2potentiallyoccludableangles.