, ▁tra uma , ▁ab use ▁of ▁an a est het ics ▁or ▁chron ic ▁top ical ▁treat ments , ▁chemical ▁burn s ▁or , ▁use ▁of ▁contact ▁l enses . ▁It ▁is ▁also ▁necessary ▁to ▁investigate ▁the ▁possible ▁presence ▁of ▁di ab etes ▁or ▁other ▁system ic ▁dise ases ▁such ▁as ▁multiple ▁s cl eros is . ▁ ▁The ▁clin ical ▁exam ination ▁is ▁usually ▁performed ▁through ▁a ▁series ▁of ▁assess ments ▁and ▁tools : ▁ ▁General ▁exam ination ▁of ▁c ran ial ▁n erves , ▁to ▁determine ▁the ▁presence ▁of ▁n erve ▁damage . ▁ ▁E ye ▁exam in ations : ▁ ▁Complete ▁eye ▁exam ination : ▁exam ination ▁of ▁the ▁e y el ids , ▁bl ink ▁rate , ▁presence ▁of ▁infl am mat ory ▁re actions ▁and ▁secret ions , ▁cor ne al ▁ep ith el ial ▁alter ations . ▁ ▁Cor ne al ▁sens itivity ▁test : ▁performed ▁by ▁placing ▁a ▁cot ton ▁w ad ▁or ▁cot ton ▁thread ▁in ▁contact ▁with ▁the ▁cor ne al ▁surface : ▁this ▁only ▁allows ▁to ▁determine ▁whether ▁cor ne al ▁sens itivity ▁is ▁normal , ▁reduced ▁or ▁absent ; ▁or ▁using ▁an ▁est h esi ometer ▁that ▁allows ▁to ▁assess ▁cor ne al ▁sens itivity . ▁ ▁T ear ▁film ▁function ▁test , ▁such ▁as ▁Sch ir mer ' s ▁test , ▁and ▁te ar ▁film ▁break - up ▁time . ▁ ▁Fl u ores ce in ▁eye ▁st ain ▁test , ▁which ▁shows ▁any ▁damage ▁to ▁the ▁cor ne al