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EW NEWS & OPINION 24 November 2017 by Liz Hillman EyeWorld Staff Writer significant alterations in optic radia- tion connectivity, reduced optic ra- diation white matter concentration, reduced gray matter concentration in the visual cortices, and reduced optic chasm volume. Prior to this research, one of the study's authors, Alessandro Arrigo, MD, Department of Ophthalmology, San Raffaele University, Milan, Italy, and Department of Biomedical Sci- ences and Morphological Functional Imaging, University of Messina, Messina, Italy, said there were few investigations looking into Parkin- son's disease and the intracranial visual system. Although, Dr. Arrigo added, a number of visual symptoms described in previously published lit- erature referred to changes occurring at this level. "Our findings describe pro- found alterations of the intracranial visual system already present at the diagnosis of Parkinson's disease," Dr. Arrigo said. He added later that the hopeful target of future research is the development of visual biomark- ers for earlier diagnosis of Parkin- son's disease. The investigators wrote in the paper that while their research found "significant damage to the intracranial visual system […] we cannot determine whether the alter- ations along these visual pathways are secondary to retinal degenera- tion or are primary." Dr. Arrigo explained this point further to EyeWorld. "It is possible that retinal alterations may have an influence on intracranial visual system ones and vice versa," he said. "On the other side, although a deep multimodal imaging investi- gation of retinal alterations was not performed in our study, if stronger retinal alterations had been present in our patients, these would have caused indicative signs already during ophthalmologic investiga- tion. For this reason, in my opinion, it is more likely that a progressive concomitant degeneration process of the entire visual system (intra- and extracranial) might occur in Parkinson's disease patients, taking into account possible 'exceptions to the rule.'" The current method of diagnos- ing Parkinson's patients based on motor and cognitive assessments means it might already be "too late" for possible interventions that could potentially help reduce the dis- ease's progression and help patients maintain a better quality of life, Dr. Arrigo said. "Although all of our senses are fundamental, visual dysfunc- tions may have a worse impact on patients' quality of life both in terms of autonomy and everyday life. Hence, the take-home message for all clinicians, not only ophthalmol- ogists, is to take into account visual symptoms and to include ophthal- mologic investigation in Parkinson's disease patient management," Dr. Arrigo said. "Furthermore, if the relationship between visual system alterations and PD pathological mechanisms were so strict, it would be plausible to take advantages, in the future, from visual investiga- tions, both clinical and instrumen- tal, for patients' follow-up as well as for assessing positive and negative effects of therapeutic procedures." Mark Falls, MD, section chief in ophthalmology, Department of Surgery, INOVA Fairfax Hospital, Fairfax, Virginia, said common ocu- lar problems in known Parkinson's disease patients are dry eye and tear film dysfunction. "As the disease progresses, the blink reflex decreases so less blinking results in poor wet- ting of the ocular surface. That also contributes to the decline in reading ability and comfort," he said. "There is also an association with conver- gence insufficiency." Burt Ginsburg, MD, Retina Vitreous Associates, Houston, whose original background was in internal medicine before he entered oph- thalmology, said in addition to dry eye he notices more pronounced downward gaze and differences in eye movements in patients with Parkinson's disease. He said there is a change in the velocity of their ver- tical movement looking up or down and horizontally. "There's a slowness in the synchronized movements," Dr. Ginsburg said. If Dr. Ginsburg suspects that something neurological might be going on with patients based on their ocular movements, he will refer them to a neurologist or neu- ro-ophthalmologist. The next step for the research regarding Parkinson's disease and the intracranial visual system, Dr. Arrigo said, is to better assess visual symptoms of Parkinson's disease patients and relate them to retinal and intracranial alterations. "The goal is to better catego- rize visual dysfunctions in order to develop possible visual biomarkers more related to Parkinson's disease than other causes," Dr. Arrigo said, adding later that this will involve better categorizing Parkinson's disease visual dysfunctions as well as timing and progression. EW References 1. Wolters ECh, et al. Parkinson's disease: premotor clinico-pathological correlations. J Neural Transm Suppl. 2006:309–19. 2. Arrigo A, et al. Visual system involvement in patients with newly diagnosed Parkinson disease. Radiology. 2017 Jul 11:161732. Epub ahead of print. Editors' note: The sources have no financial interests related to their comments. Contact information Arrigo: alessandro.arrigo@hotmail.com Falls: nfarano@youreyes.org Ginsburg: bradg@gcomworks.com Study finds significant intracranial visual system damage in newly diagnosed Parkinson's patients N onmotor symptoms of Parkinson's disease, in- cluding changes to visual function, can precede the more noticeable motor effects that often lead to the initial diagnosis of the disease by more than a decade. 1 Previous studies have described the visual changes that can take place with Parkinson's disease, but a recent paper describes research that showed how changes in the visual system could be a possi- ble early biomarker of the disease. The study published in Radiol- ogy, the journal of the Radiological Society of North America, revealed differences at the intracranial level in recently diagnosed Parkinson's patients and healthy subjects. 2 More specifically, using MRI and voxel- based morphometry, an automated way to assess structural changes in the brain, the researchers found Changes in visual system could be future biomarker for early Parkinson's disease Left and right optic radiation (OR) image in a representative subject overlaid onto a T1- weighted axial volume image of the same subject. OR images were obtained on the basis of diffusion-weighted volume images by means of constrained spherical deconvolution fitting and related tractography. Each bundle was automatically colored according to tract main directionality: red for left to right, green for anterior to posterior, and blue for inferior to superior. Source: Alessandro Arrigo, MD Research highlight

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