ELECTRON-MICROSCOPY STUDY OF EXPLANTED INTRAOCULAR LENSES FROM CLINICALLY NONINFECTED EYES

Purpose: To determine whether intraocular lenses (IOLs) in clinically noninfected eyes are coated with a significant, bacteria-containing bi ofilm. Setting: The Oxford Eye Hospital, Oxford, United Kingdom. Metho ds: Twenty-six IOLs, removed for reasons other than endophthalmitis fr om 26 patients attending the Oxford Eye Hospital over a 3 year period, were examined by electron microscopy. immediately following explantat ion, the IOL was placed in glutaraldehyde 4% in 0.1 M phosphate buffer solution and processed for scanning electron microscopy (SEM). Areas of interest were reprocessed for transmission electron microscopy (TEM ). Results: There was no evidence of a bacterial biofilm on any IOL. i n 5 IOLs, significant host cellular debris was seen at the lip of the haptic or at the optic-haptic junction. In 4 of them, clusters of cocc oid-shaped structures were seen at the optic junction on SEM, but exam ination by TEM showed these structures to be melanosomes, not bacteria . Conclusion: We found no evidence to suggest that a significant numbe r of IOLs are coated with a bacterial biofilm in clinically noninfecte d cases. We advocate the use of TEM to distinguish between coccold bac teria and melanosomes.