▁to ▁deg ener ation ▁of ▁the ▁ret ina . ▁ ▁The ▁first ▁known ▁case ▁of ▁published ▁recovery ▁from ▁blind ness ▁is ▁in ▁ 1 7 2 8 , ▁of ▁a ▁blind ▁ 1 3 - year - old ▁boy ▁by ▁William ▁Ch es el den . ▁Ch es el den ▁presented ▁the ▁celebrated ▁case ▁of ▁the ▁boy ▁of ▁th ir teen ▁who ▁gained ▁his ▁sight ▁after ▁removal ▁of ▁the ▁l enses ▁rendered ▁op aque ▁by ▁cat ar act ▁from ▁birth . ▁Despite ▁his ▁youth , ▁the ▁boy ▁encountered ▁prof ound ▁difficulties ▁with ▁the ▁simplest ▁visual ▁per ception s . ▁Descri bed ▁by ▁Ch es el den : ▁When ▁he ▁first ▁saw , ▁he ▁was ▁so ▁far ▁from ▁making ▁any ▁judgment ▁of ▁distances , ▁that ▁he ▁thought ▁all ▁object ▁whatever ▁touched ▁his ▁eyes ▁( as ▁he ▁expressed ▁it ) ▁as ▁what ▁he ▁felt ▁did ▁his ▁skin , ▁and ▁thought ▁no ▁object ▁so ▁agree able ▁as ▁those ▁which ▁were ▁smooth ▁and ▁regular , ▁though ▁he ▁could ▁form ▁no ▁judgment ▁of ▁their ▁shape , ▁or ▁guess ▁what ▁it ▁was ▁in ▁any ▁object ▁that ▁was ▁ple asing ▁to ▁him : ▁he ▁knew ▁not ▁the ▁shape ▁of ▁anything , ▁nor ▁any ▁one ▁thing ▁from ▁another , ▁however ▁different ▁in ▁shape ▁or ▁magnitude ; ▁but ▁upon ▁being ▁told ▁what ▁things ▁were , ▁whose ▁form ▁he ▁knew ▁before ▁from ▁feeling , ▁he ▁would ▁carefully ▁observe , ▁that ▁he ▁might ▁know ▁them ▁again ; ▁A ▁total ▁of ▁ 6 6 ▁early ▁cases ▁of ▁patients ▁who ▁under w ent ▁cat ar act