Altered perception of floaters in dementia causing self-inflicted injuries

Dear Editor, A 74 years old male patient with history of Parkinson disease and vascular dementia presented to the eye clinic with his wife, who is his primary caregiver. The patient reported a multiple year history of complaining of “flies” around his head, which were a source of considerable agitation. He was so bothered by constantly seeing these flies that he carried a custom flyswatter with him (Figure 1) at all times. His wife had fashioned this with padded edges after he sustained multiple self-inflicted corneal abrasions while swatting the “flies.” No other injuries were reported or examined during his clinic visits. He had also recently obtained a can of bug spray, which his wife was fortunately able to take before he sprayed himself in the face. He wore a patch over the right eye, which he reported helped with the flies. The patient had a known history of vitreous floaters, and had been evaluated by multiple ophthalmologists in the years prior to his presentation in our clinic. The patient’s dementia led him to misinterpret his vitreous floaters as a constant barrage of insects, which added significant morbidity to his mental illness. He and his wife had been told that vitreous floaters were the likely cause of his symptoms, but that there were no safe and effective options for eliminating them. When they presented to our clinic, the patient’s wife reported that the patient’s agitation regarding the flies was worsening and adding to her already significant challenges as his primary caregiver. Exam showed best corrected visual acuity of 20/60 OD and 20/40 OS. The remainder of exam was significant only for pseudophakia and posterior vitreous detachment with Weiss ring of both eyes, and vitreous condensations (right greater than left). A discussion of the risks and benefits of pars plana vitrectomy for removal of floaters was conducted with the patient and his wife, who both agreed to proceed with surgery. After obtaining informed consent, consecutive uneventful pars plana vitrectomies were performed, first on the right eye and then six weeks later on the left when symptoms persisted. Large central vitreous condensations in the visual axis of both eyes were noted intraoperatively (Figure 2). At postoperative one month from the second eye, the patient reported complete relief of symptoms. He still preferred to hold his flyswatter occasionally but his wife explained this was more of “security blanket” and that he no longer swatted at himself .The patient reported his vision was improved enough that he could now “see out of both eyes” and he no longer needed to patch the right eye. His wife reported considerable reduction in his overall agitation. Visual acuity without