<prompt> Phenol red test Methyl red thread test for dry eye, true isNeed instillation of anesthesia before doing the testNeed a ph meter to interpretColor changes if there is mucin deficiencyColor changes from white to red on contact with tear film and is used to measure the dryness status of eye  <response>: Phenol Red Thread test is the test to detect dry eye severity. When in contact with tear film it changes its colour from white to yellow to red. Its main advantage over Schirmertest is: aIt is Less time consuming as compared to schirmer test15 sec bAnaesthesia of cornea is not required cOn the contact of tear strip with the tear it turns red dCan be done in children easily eReflex tearing is minimal fDifferentiates between aqueous deficient non aqueous deficient eyes 