[The evaluation of surface deposits on frequent replacement lenses by scanning electron microscopy (SEM)]

The aim of our study was to find the method of preparation of soft contact lenses for examination by SEM and next evaluation of deposits on the surfaces of frequent replacement lenses.

Frequent replacement contact lenses (Acuvue) stored in physiological saline, distilled water and sterile, dry container were prepared for examination by SEM (Novoscan 30). The best quality preparations were made from contact lenses stored in sterile, dry container and dried at room temperature. Acuvue contact lenses were taken from five young, healthy persons after one, two, three and four weeks of wearing. All the lenses were examined by SEM.

We observed nearly all the components of tear film on the surfaces of the lenses. Flat, amorphic protein, crystalline deposits, fibrinous structures were usually observed. Sometimes the nectrotic cell were seen. In one preparation we found bacteria. The amount of deposits was not high and did not increase with four weeks time of lens usage. The quality and quantity of deposits were individually variable.

The methods we choose let us to prepare good quality preparations of soft contact lenses for examination by SEM. On the surfaces of the frequent replacement contact lenses we found only a small quantity of deposits.