The researchers followed up with the 87 participants on whose contact lenses they detected Acanthamoeba. Forty-two of these participants responded with information about their ocular health since they joined the study. Only one of them reported suffering from keratitis, while a few others said they had suffered from conjunctivitis. The participant who reported keratitis declined their offer to determine whether her infection was caused by Acanthamoebae.
The 0.6% incidence of cultivatable Acanthamoebae in the Madrid contact lenses contrasts with a 65.9% incidence in the Canary Islands. The researchers speculated that the difference could be attributed to the warm climate and dust in the Canary Islands.
The researchers noted that methods for cultivating Acanthamoeba have a sensitivity of about 50%, which could account for the discrepancy between the cultivation results and the PCR results. It's also possible that some Acanthamoebae died of starvation between the last use of the contact lenses and the time when the researchers attempted to cultivate the organisms, they point out.
In concluding, they highlight the correlation between not washing lens cases and evidence of contamination. Although the correlation didn't quite reach statistical significance, they recommended that lens wearers need to pay more attention to this protocol.
Specifically, lens wearers should rub the cases with a clean finger and a fresh multipurpose disinfecting solution for 5 seconds, rinse them with a fresh solution, wipe them with a tissue and air-dry them face down on a tissue for 6 hours, they said.
Finally, the researchers point out that the results of this study should not be interpreted to mean that the other lens hygiene practices they investigated are safe to ignore.