▁to ▁storage ▁as ▁this ▁extends ▁its ▁possible ▁storage ▁time . ▁ ▁For ▁the ▁operation ▁procedure , ▁the ▁patient ▁is ▁an a est het ised ▁and ▁the ▁dam aged ▁or ▁dise ased ▁cor ne al ▁button ▁will ▁be ▁removed ▁using ▁a ▁bl aded ▁instrument ▁called ▁a ▁tre ph ine ▁( appro xim ately ▁ 8 . 0 – 8 . 5 mm ▁in ▁diameter ). ▁A ▁cor ne al ▁button ▁of ▁matching ▁size ▁is ▁then ▁put ▁in ▁place ▁of ▁the ▁removed ▁t issue ▁and ▁st itch ed ▁in ▁place . ▁Usually , ▁twelve ▁clock - hour ▁n yl on ▁st itch es ▁are ▁used ▁with ▁a ▁continuous ▁band ▁n yl on ▁st itch . ▁ ▁The ▁procedure ▁takes ▁approximately ▁ 6 0 – 9 0 ▁minutes ▁however , ▁a ▁few ▁months ▁will ▁be ▁required ▁for ▁vision ▁to ▁return ▁to ▁what ▁it ▁was ▁like ▁preceding ▁the ▁operation ; ▁and ▁continue ▁to ▁improve ▁from ▁then ▁on . ▁ ▁Appro xim ately ▁ 1 2 – 1 8 ▁months ▁after ▁the ▁operation , ▁all ▁st itch es ▁will ▁be ▁removed . ▁During ▁this ▁time , ▁anti - re jection ▁dro ps ▁will ▁be ▁needed ▁to ▁minim ise ▁infl amm ation ; ▁the ▁dos age ▁of ▁which ▁is ▁carefully ▁monitor ed ▁by ▁a ▁cor ne al ▁sur geon . ▁ ▁Due ▁to ▁the ▁sw elling , ▁it ▁is ▁impossible ▁to ▁predict ▁the ▁quality ▁of ▁vision ▁without ▁removing ▁the ▁st itch es . ▁A ▁few ▁months ▁after ▁the ▁st itch es ▁are ▁removed , ▁measurements ▁are ▁made ▁of ▁the