Conjunctiva is composed of non-squamous epithelial cells interspersed with goblet cells, which is a secretory epithelium. Squamous metaplasia is a transformation to non-secretory epithelium, ‘keratinised’ and enlargement of the conjunctival non-goblet cells and relatively shrunken nuclei are seen on impression cytology. These changes have been reported in soft contact lens wearers. This pilot study of impression cytology taken from interpalpebral conjunctiva of 23 white female soft contact lens wearers versus 23 age matched healthy white female optometry students. The aim of the study was to further define bulbar conjunctival cell morphology in squamous metaplasia in long-term contact lens wearers in an age-matched population. All contact lens wearers showed substantial cell changes compared with controls. The results indicate in concordance with other studies that squamous metaplasia can continue to develop or persist after an average of six years of successful contact lens wear. Comparison with other reports can be confusing due to the use of different grading scales. The authors report that nuclear pyknosis (shrinking of nuclear size) does not occur, rather there is enlargement of the nucleus along with the cell size. Such cellular changes don’t always correlate with “notable fluorescein staining of exposed bulbar conjunctiva.” This interesting report doesn’t correlate findings to clinical presentation to a hospital eye service with ocular surface discomfort associated with contact lens wear. Most of the subjects recruited reported mild occasional ocular surface discomfort associated with contact lens wear. 

Objective assessment of squamous metaplasia of conjunctival epithelial cells as associated with soft contact lens wear versus non-lens wearers.
Doughty MJ.
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Sharmina Khan

Moorfields Eye Hospital, London, UK

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