CDC reveals cause of fungal outbreak

October 1, 2006

Researchers from the US based Centers for Disease Control and Prevention (CDC) have released a report explaining the causes behind the well-publicised dramatic rise of fungal eye infections among Americans.

Researchers from the US based Centers for Disease Control and Prevention (CDC) have released a report explaining the causes behind the well-publicised dramatic rise of fungal eye infections among Americans.

The findings suggest that a combination of poor contact lens wearer hygiene and compliance and the composition of the ReNu with MoistureLoc contact lens solution (Bausch & Lomb) are to blame. The CDC confirmed 164 cases of Fusarium keratitis in 33 states and one US territory and established a clear link between the corneal infection and the contact lens solution.

The ReNu with MoistureLoc solution was removed from the market in May of this year when reports of the infection emerged.

VA not dependent on corneal asphericity

Visual acuity (VA) and contrast sensitivity after wavefront-guided LASIK are not dependent on corneal asphericity, according to the results of a study published in the August issue of Optometry & Vision Science.

Kuang-Mon Ashley Tuan OD, PhD, FAAO and Dimitri Chernyak PhD, conducted a retrospective analysis of 160 eyes, at six clinical sites, that had undergone wavefront-guided LASIK. Six months prior to surgery, corneal topography, VA and contrast sensitivity data were collected. The topographically measured corneal surface of each eye was fitted to a conic, and a Q value computed for a 5.5 mm pupil. Multivariate regression analysis was performed to evaluate the correlation between Q value and visual function.

The results showed that preoperative corneas exhibited negative conic shape constants, while postoperative corneas were equally divided between positive and negative conics. No statistically significant correlation was found between corneal shape and VA or contrast sensitivity function. Likewise, no significant correlation between changes in corneal asphericity and changes in VA and contrast sensitivity was detected.

Tuan and Chernyak concluded that VA and contrast sensitivity after wavefront-guided LASIK are not dependent on corneal asphericity and that, neither preserving nor inducing asphericity, ensures better visual outcomes. They believe that better visual outcomes are more likely to result from the application of a customized shape rather than a standard conic shape.

Age not a risk factor in phaco complications

Scott Robbie and colleagues from Addenbrooke's Hospital NHS Trust, St George's Hospital and Moorfield's Eye Hospital, UK, examined 1,441 consecutive patients undergoing phacoemulsification. Subjects were assessed preoperatively and data was prospectively collected on the occurrence of intraoperative complications and entered into a database. Logistic regression was used to examine any evidence of an association between age and the risk of complications, while rates of complications were also compared between patients aged 88 or more and those younger, and between patients aged 96 or more and those younger.

The researchers found no statistically significant association between age and risk of intraoperative complications. Furthermore, little evidence was found to suggest that those aged 88 or more and those aged 96 or more had an increased risk compared with younger patients, however, the authors conceded that the sample numbers were small.