Rehabilitation of visual field loss: Use of yoked prism in a homonymous hemianopic patient Mary Kutch, OD Johnathan M. Wainwright VAMC and Pacific Cataract & Laser Institute Walla Walla, Washington

Abstract Cerebral vascular accidents (CVAs) can have a myriad of neurological, perceptual, and functional effects. A recent CVA victim and retired professor uses yoked prism glasses and trains with the AcuVision1000 to compensate for his homonymous hemianopsia.

Patient Background a f x m g 69yowm retired university professor presents for a low vision evaluation 6 weeks following a left occipital hemorrhagic CVA with extension into the parietal and temporal areas CC: Right side of VF OD considerably constricted, OS “fine,” with improvement since onset Tilts pages to read, missing ends of long words No problems recognizing faces, figures, or writing letters & words, but doesn’t recognize groups of letter as words- has to sound them out letter by letter and combine sounds

Additional background Diagnosed by speech & hearing lab with Pure Alexia, aka Alexia without Agraphia Cognition and memory test normal Extreme difficulty with figure-ground perception found on later VIP assessment Goals: Reading with fluency, resuming driving and motorcycle riding

Exam Findings BCVA 10/10 OD, OS, no Amsler defects OD/OS, Pupils ERRL, Slit Lamp- unremarkable for age, IOPs 14mmHg OU, DFE: c/d 0.3 OU c HRT, Mild ERM OS, Peripheral retina: benign pigmentary changes OU Goldmann bowl perimetry: Right homonymous hemianopic field loss extending 40’ from fixation OU No right-side visual neglect, “clock dial” test negative Baseline Acuvision 1000 testing for functional visual field/hand-eye coordination

Treatment Plan Shift perceived visual midline toward seeing side Testing reveals preferred orientation was yoked base up and right; Rx yoked prism for separate distance and near glasses to bring the non-seeing visual field into the seeing Increase awareness of right visual field and eye movement with weekly therapy on AcuVision1000 training board and 20^ yoked base-right prism glasses atop distance Rx Continue bi-weekly sessions with speech & hearing for re-learning reading fluency with word recgonition, weekly sessions with occupational therapy to increase horizontal eye movements and tracking, and VIP consult ordered. Referral to driving rehabilitation specialist for evaluation

AcuVision 1000 Use / Advanced Features: http://www.opt.pacificu.edu/ce/catalog/15876-GO/Slide22N.JPG

Training Prism Glasses In-office use only: Rotate in frame to desired angle http://www.bernell.com/product/1735/30

Progress Report After only 2 weeks of fixator board therapy and full-time wear of lower amounts yoked prism, PC demonstrated increased speed and accuracy finding right-side targets, which continued to improve in the following weeks No longer tilting page to read & less difficulty with ends of long words “missing” Increased saccades/searching eye movement Word recognition speed increased with other therapy- reduced reading speed of set block of text by 200% Pt resumed driving with a passenger after go-ahead from driving rehab assessment Later VIP assessment showed very belabored figure-ground discrimination, which we correlated to finding stop signs and traffic obstacles, and cautioned against driving due to this shortcoming. Cautioned against motorcycle riding with prism distance Rx as well

Other Research Says… Kunicki found eye-hand coordination improved in both short- and long-term training on the AcuVision 1000 in normal college-age patients. In clinical trials by Rousseaux, et. al, 79% of stroke patients with spatial neglect signs increased ease in reading single words as well as general function and safety with the use of prism for rehabilitation. Yoked prism was partially successful for Rossi et al., in a study of 39 stroke patients with homonymous hemianopsia using 15-diopter plastic press-on Fresnel prisms for four weeks. The subjects’ visual perception tests scores improved, but function in the form of activities of daily living (ADL) did not. While Hedges, et. al. found a lower rate of success than Rousseaux (21% vs 79%) in a similar study, he noted that those who did not find significant functional improvement expressed appreciation that something had been tried, and proper motivation and instruction are essential in the employment of prism therapy

References American Stroke Association http://www.strokeassociation.org/presenter.jhtml?identifier=1033 Hedges TR Jr, Stunkard J, Twer A. “Fresnel prisms—their value in the rehabilitation of homonymous hemianopsias” Klin Monatsbl Augenheilkd. 1988 May; 195(5):568-71. Henderson, Patricia. “Cranial Nerves V- VII and Higher Cortical Function.” Lecture for Indiana University Disease III: Neurooptometry, April 2006. Kunicki, M. “Can eye-hand coordination be trained on the AcuVision 1000?” Honors Thesis, University of Sydney, Austraila. Rossi PW, Kheyfets S, Reding MJ. “Fresnel prisms improve visual perception in stroke patients with homonymous hemianopia or unilateral visual neglect.” Neurology. 1990 Oct; 40(10):1597-9. Rousseaux M, Bernati T, Saj A, Kozlowski O. “Ineffectiveness of prism adaptation on spatial neglect signs.” Stroke. 2006. Feb; 37(2):542-3. Szlyk JP, Seiple W, Stelmack J, McMahon T. “Use of prisms for navigation and driving in hemianopic patients.” Ophthalmic Physiol Opt. 2005 Mar; 25(2):128-35.

Conclusions Thank you for your time! Don’t forget there are options for rehabilitating your motivated stroke patients with hemianopic field loss to make the most of their remaining vision. Thank you for your time!