An impression cytology based study of ocular surface in an urban population

To assess the health of ocular surface in a defined urban population, conjunctival goblet cell density and degree of surface squamous metaplasia were utilized as study tools. Two thousand names of those aged between 20 and 79 years from the 2006 electoral register in ward number 63 of Kolkata Corporation area were initially selected. Normal healthy human volunteers without any history of ocular surface disorder were recruited and divided into five age-groups. Impression cytology samples were obtained from interpalpebral part of bulbar conjunctiva from all the participants fixated and stained by a single observer. A stratified, clustered, disproportionate, random sampling method was used. The software used in the statistical analysis was EPI Info. The tests applied were t test and ANOVA. A variation in the number of goblet cells according to gender (women having less cells) and age (20-30 years group having the highest number of cells) was found. Those working outdoors were found to have fewer goblet cells compared to those who stay indoors. The majority of the people had grade 1 cytological appearance in both males and females. There was no statistically significant difference in Nelson's grading with age. People using coal and kerosene to cook were found to have a smaller goblet cell density than those who cooked on LPG or those who did not cook at all. Besides age and sex, environmental factors like the method of cooking and occupational variables (like outdoor activity, prolonged period of computer use, etc.) modify the health of the ocular surface. The results of this study will help put these findings into perspective as public health problems.