title: Identification of ocular surface squamous neoplasia by in vivo staining with methylene blue.
abstract: OBJECTIVE
  To evaluate the diagnostic accuracy of methylene blue used as a non-invasive in vivo stain to detect ocular surface squamous neoplasia (OSSN).
  
  
  METHODS
  A test validation study was performed according to Standards for the reporting of diagnostic accuracy studies (STARD) guidelines on 75 consecutive patients who presented with ocular surface lesions suspicious of OSSN. Methylene blue 1% was instilled in vivo following local anaesthetic. Stain results were documented photographically and read by an independent observer. Lesions were excised at the same visit and evaluated histologically by pathologists who were blind to the stain results. Sensitivity, specificity, positive and negative predictive values were determined.
  
  
  RESULTS
  Thirty-three patients had histologically malignant lesions, of which 32 stained with methylene blue, and 42 patients had benign or premalignant lesions, of which 21 stained with methylene blue. Methylene blue had a sensitivity of 97%, specificity of 50% and positive and negative predictive values of 60% and 96%, respectively.
  
  
  CONCLUSIONS
  The topical application of methylene blue is a simple, inexpensive, non-invasive diagnostic test that can be helpful in excluding malignant ocular surface lesions but cannot replace histology as gold standard for diagnosis of OSSN.
authors.affiliation: Division of Ophthalmology, University of Cape Town, , Cape Town, Western Cape, South Africa.
authors.forename: Jonel
authors.initials: J
authors.lastname: Steffen
authors.forename: James
authors.initials: J
authors.lastname: Rice
authors.forename: Karin
authors.initials: K
authors.lastname: Lecuona
authors.forename: Henri
authors.initials: H
authors.lastname: Carrara
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002278:Carcinoma in Situ / Q000175:diagnosis*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D004396:Coloring Agents; D003230:Conjunctival Neoplasms / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008751:Methylene Blue; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D008751:Methylene Blue
keywords: Conjunctiva; Cornea; Diagnostic Tests/Investigation; Neoplasia