Conjunctival impression Cytology; An Aid in the Diagnosis of Dry Eye Syndromes

Dry eye syndrome is a multifactorial disease of tears and ocular surface resulting in ocular discomfort, visual disturbances and damage to the ocular surface with tear film instability. Diagnosis is based on symptom based assessment, clinical examination and tests like Schirmer's, tear film break up time and Rose bengal staining of ocular surface. Conjunctival impression cytology (CIC) is a non-invasive, easy to perform test which can be used with other tests to diagnose dry eye. The present study aimed at evaluating the usefulness of impression cytology in the diagnosis of dry eye syndromes and to correlate the results of impression cytology with their aetiology. Materials and Methods: 150 eyes which met the inclusion criteria were subjected to clinical examination and diagnostic tests after obtaining informed consent. CIC samples were obtained from temporal bulbar conjunctiva and stained with periodic acid Schiff, Hematoxylin and eosin. The epithelial cell morphology was graded according to Nelson. Results: The eyes showed normal, grade 1, grade 2 and grade 3 scores of CIC in 26 (17.33%), 41 (27.33%), 55 (36.67%) and 28(18.67%) respectively. Abnormal CIC increased with declining schirmer's, tear break up time values less than 10 seconds and increasing Rose Bengal staining. Thyroid ophthalmopathy and keratoconjunctivitis sicca were associated with severe while xerophthalmia was associated with mild cytological changes. Conclusion: Diagnostic tests when used in combination are more effective than when used alone in dry eye. CIC, a noninvasive and simple test can be used with other tests for the diagnosis and monitoring treatment of dry eye.