Morphological changes of the conjunctival epithelium in contact lens wearers evaluated by impression cytology

Conjunctival changes induced by rigid, gas-permeable and soft contact lenses (CL) were investigated using impression cytology. A scoring system based on seven parameters (specimen cellularity, cell-to-cell contacts, nucleus/cytoplasm ratio, chromatin, goblet cell distribution, keratinisation, inflammatory cells) was used to evaluate the morphological results.

One hundred and seventy-two CL-wearing eyes and 40 control eyes were examined. The population was divided into three groups: group 1, control eyes; group 2, asymptomatic CL-wearing eyes; group 3, CL-wearing eyes with intolerance problems. Impression cytology was carried out and all specimens were evaluated according to a scoring system.

Group 1 specimens always showed normal features in the conjunctival epithelium. In group 2, rigid and gaspermeable lenses produced greater changes in conjunctival morphology than soft lenses, especially as regards cellularity, nucleus/cytoplasm ratio, goblet cell distribution and total score. On the contrary, in group 3 wearers of soft lenses showed higher partial and total scores than wearers of gas-permeable and rigid lenses.

In asymptomatic CL wearers conjunctival morphology was better preserved in wearers of soft lenses. In patients with intolerance problems, wearers of soft lenses showed the worst cytological features. Impression cytology, evaluated with this scoring system, can be used to demonstrate epithelial damage occurring in CL-wearing patients.