Objective assessment of contact lens wear-associated conjunctival squamous metaplasia by linear measures of cell size, shape and nucleus-to-cytoplasm ratios

Michael Doughty

Research output: Contribution to journalArticle

Abstract

The purpose of this research was to objectively assess the cell and nucleus dimensions of human bulbar conjunctival cells in female soft contact lens wearers to illustrate a method for assessment of the nucleus-to-cytoplasm ratio based on simple linear measures. Impression cytology samples were taken from the nasal side exposed bulbar conjunctiva surface from 12 young adult, white European females with a history of successful daily soft contact lens wear. A Millcell(®)-CM filter was used after topical anesthesia, which was stained with Giemsa. Color images of portions of the cells, in a monolayer at 200× magnification by light microscopy, were graded by the Nelson scale and then a projection overlay method was used to outline the cell and nucleus borders. The cell longest dimension (LONG), shorter dimension (SHORT), and the longest dimension of the nucleus (NUCLONG) were measured. A nucleus-to-cytoplasm N:C ratio was calculated from (LONG-NUCLONG)/NUCLONG. Cells had appearances consistent with a grade 2 or 3 squamous metaplasia and were moderately enlarged (mean LONG ± SD of 46.0¿±¿3.8 microm), only slightly elongated (mean LONG:SHORT ratio of 1.397¿±¿0.101) and the nucleus size was consistently greater than normal (man 12.8¿±¿1.3 microm). A calculation of N:C showed a relatively wide range of values with average values from 1:2.143 to 1:3.317 (for an overall mean of 2.675¿±¿0.371).

Original languageEnglish
Pages (from-to)599-606
Number of pages8
JournalCurrent Eye Research
Volume36
Issue number7
Publication statusPublished - 1 Jul 2011

Keywords

  • squamous metaplasia
  • contact lenses
  • cytology
  • conjunctiva
  • vision sciences

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