Abstract
Purpose :
Acanthamoeba Keratitis (AK) is a severe vision-threatening ocluar infecction which has traditionally been difficult to diagnose. Contact lens wearers, especially soft contact lens, have been recognized as the number one risk factor for AK. Treatment course is well known to be lengthy and potentially not fully effective. In vivo confocal microscopy (IVCM) is a non-invasive imaging modality that allows direct visualization of potential causative infectious pathogens in real time with an established utility in the diagnosis of AK. In this study, we aim to assess the utility of HRT3/RCM IVCM in monitoring disease progression in contact lens wearers with culture confirmed keratitis.
Methods :
Fourteen eyes from 11 patients with cultured confirmed Acanthamoeba keratitis were included in this retrospective study. IVCM imaging was performed during the patient’s first visit as well as at following visits. All available confocal sequences from each eye were reviewed and graded by experienced confocal microscopists in a masked fashion. Density of acanthamoeba infiltration were graded. The change in cysts densities for each visist is calculated as a percentage of baseline cysts density measured at each patient’s initial diagnositc visit. A Univariate regression analysis was performed to assess the association between treatment and changes in cysts density per month of treatment.
Results :
All fourteen eyes had microbiolgy culture confirmed AK. Acanthamoeba cysts were identified by IVCM in all of these culture confirmed cases. Cysts were identified in the central corneal area in each of these 14 eyes at the initial clinical visist. Mean cysts density in the central cornea at presentation was 99±64.9 /mm2 (range: 38-255 /mm2) [Figure 1].
Based on our univariate regression analysis, cysts density in our study population significantly decreased by about 5.29 percent with each month of antiamaebic treatment (p=0.001, R squre =0.41) [Figure 2].
Conclusions :
Acanthamoeba cysts density reduction with treatment can be monitored by IVCM. This parameter may be used clinically in prognostication and disease monitoring in AK, especially response to treatment. The ophthalmologist should consider IVCM a powerful tool in the armamentarium for the diagnosis and monitoring of AK cases.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.