The plague that won't simply go away: acanthamoeba keratitis

Review of complications associated with contact lenses from unregulated sources of supply

OBJECTIVE

To review existing studies and case reports regarding complications associated with contact lenses (CLs) from unregulated sources of supply and to identify any relevant trends.

METHODS

A systematic literature search was performed to locate publications concerning complications associated with CLs obtained from unregulated sources of supply.

RESULTS

A total of 23 articles were identified that represent 70 individual cases. All 8 of the pre-2006 case reports originated from the United States and the United Kingdom, whereas from 2006 onwards, only 2 of the 15 reports came from these locations. Over-the-counter supply accounted for 73% (51/70) of cases, whereas 17% (12/70) were borrowed or shared lenses and 6% (4/70) lenses were obtained through the Internet. Nearly, three quarters of patients (30/42, 71%) waited longer than 48 hours after the onset of symptoms before seeking medical attention; 10 patients waited longer than a week, and 5 longer than a month. Microbial keratitis (MK) was reported in 43 (61%) patients, with permanent damage occurring in 72% (31/43) of patients followed to conclusion. Known risk factors associated for MK were present in all cases irrespective of whether the patients developed MK.

CONCLUSIONS

There are various reasons to presume that the unregulated supply of CLs might result in the use of inappropriate lenses, increase the risk of poorer lens hygiene, and militate against the prompt treatment of any consequent complications. There is some indication that the introduction of regulations to control the supply of plano CLs has alleviated the level of complications.

Acanthamoeba keratitis: an emerging disease gathering importance worldwide?

Acanthamoeba keratitis (AK) is increasingly being recognized as a severe sight-threatening ocular infection worldwide. Although contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are also an important cause of keratitis in non-contact lens wearers. Diagnosis of AK is challenging, and the available treatments are lengthy and not fully effective against all strains. The pathogenesis of Acanthamoeba is still under study, and the identification of the key factors involved in this process should be useful for the development of fully effective therapies. This review focuses on recent developments on AK pathogenesis and diagnosis as well as novel strategies for the evaluation of anti-amoebic agents that could be applied in the near future against these pathogens.