الفهرس 
definition of dry eyeOnly 14 pages are availabe for public view
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Abstract
Impression cytology is a technique used recently to obtain a superficial conjunctival biopsy instead of conjunctival scrapings and incisional biopsy used previously. The aim of this work was to evaluate this technique as a method for obtaining superficial conjunctival biopsy to diagnose squamous metaplasia in the conjunctival epithelium in dry eye disorder of the conjunctiva. We studied 50 eyes of 30 patients with dry eye 5 eyes from 5 normal subjects served as control. Four impression cytology specimens were obtained from each eye; tow from palpebral conjunctiva (upper and lower palpebral), and two from bulbar conjunctiva (nasal and temporal). These imprints were stained by special stains, then examined by light microscopy. Examination of impression cytology specimens from the cases and controls indicated that, Dry eyes have abnormal epithelium with decreased or absent goblet cells. The progressive decrease in goblet cells was associated with increase in the diameter of non-goblet epithelial cells; pyknotic changes in the nucleus and finally keratinization of the cytoplasm; a process known as squamous metaplasia. Conjunctival impression cytology showed four grades of squamous metaplasia (I, II, III and IV). This grading system allowed us to assess objectively the severity of the disease on the ocular surface. As the biomicroscopic changes increases in severity, the cytological changes also progressively shift from grade I to II to III and grade IV types.