Late ocular changes after closantel (Flukiver) poisoning

Abstract

PurposeTo describe late ocular changes in 5 women after harmful use of donated closantel (Flukiver).MethodsThe study included 5 women from the report published by Hoen and Hodgkin in The Lancet journal in 1993 about 11 cases of donated veterinary drug closantel use in Lithuania. We analysed medical records from 1993 to 2015 and performed eye examination of 5 suffered patients 22 years after the event.The study was conducted at the Centre of Eye Diseases,Vilnius University Hospital Santariškių Klinikos,it adhered to the tenets of the Declaration of Helsinki.Eye examination included best corrected visual acuity (BCVA), perimetry, colour vision(CV), tonometry, slit lamp evaluation, fundus photography and optical coherent tomography.ResultsIn 2015 the mean age of the patients was 49.4 years In 1993 BCVA varied from 0.08 to 1.0.Right eye (RE)in average‐ 0.66, left eye(LE) – 0.68. In 2015 BCVA varied from 0.1 to 1.0.RE in average – 0.7 and LE – 0.6.22 years after the event average visual field defect in the right eye was 24.13 dB and in the left eye ‐ 23.85 dB.CV Ishihara test showed decreased green color perception in 3 patients and 2 were not able to perform it, because of the visual field defects.The average central macular thickness 216.0 ± 36.1 µm in RE and 196.0 ± 42.0 µm in LE, retinal nerve fiber layer respectively 86.0 ± 11.0 µm and 93.2 ± 5.4 µm. Ophthalmoscopy showed atrophy of the optic nerve and changes of the retina reminding those in retinitis pigmentosa.ConclusionsClosantel is veterinary drug causing decades lasting damage of the optic nerve and retina in humans. Visual functions don't correlate with central macular and retinal fiber layer thickness.Fundus photography and perimetry reveal changes similar to retinitis pigmentosa. To our knowledge this is the first report about the late outcomes of closantel toxicity in humans.