Abstract
Purpose :
To describe the use of optical coherence tomography (OCT) in monitoring ocular disease in patients with onchocerciasis during treatment with IVM.
Methods :
We conducted a prospective cohort study in Hohoe, Ghana to the observe the effect of 150ug/kg IVM on the kinetics of microfilarial (Mf) clearance in participants with skin-snip positive onchocerciasis. Participants were divided into 3 arms according to the number of Mf in the anterior chamber (MfAC) at baseline: Group 1 had no MfAC, group 2 had between 1 – 10 MfAC, and group 3 had >10 MfAC. OCT scans were obtained at screening, day 7, month 3 and month 6.
Results :
Of the 261 participants enrolled for the study, 231 were included to receive IVM therapy. 41.5% (96/231) of participants had at least 1 MfAC (range 1-150) during their first week. 55.9% (19/34) of participants with baseline eye disease such as cataract, glaucoma, or retinopathy had at least 1 MfAC in either eye at day 0 or day 7 and 39.09% of participants without baseline eye disease had at least 1 MfAC at day 0 or day 7 (p = 0.0665). No Mf were observed in the posterior segment by fundoscopy or OCT. MfAC counts were correlated with baseline skin Mf counts (p<0.001). 72% (36/50) of persons with at least 30 Mf/mg had detectable MfAC in their first week of observation compared to 27.2% (28/103) of subjects with skin Mf counts between 1 and 10 Mf/mg. 91.8% (67/73) of participants with 1-9 MfAC and 70.6% (12/17) of those with 10 or more MfAC had complete clearance of MfAC at 6 months. OCT did not demonstrate progression of baseline eye disease during the 6 month window following IVM treatment. Retinal nerve fiber layer thickness at the optic nerve head or macular central subfield thickness were not correlated with presence of MfAC. Ocular adverse events were mild and included ocular itching (5.19%), eye pain ( 4.33 %), and watering eyes (0.87%).
Conclusions :
IVM is a safe and effective therapy at reducing microfilarial disease in the anterior chamber. In our study, participants with baseline eye disease had a higher incidence of MfAC. OCT was a useful modality to monitor ocular disease, but not for direct Mf detection. OCT did not detect exacerbation of existing eye diseases or anatomical changes in the posterior segment in the 6 months following therapy with IVM.
This is a 2020 ARVO Annual Meeting abstract.