Changing Vergence Function in Persons with Parkinson’s Disease and Convergence Insufficiency

Abstract

Purpose : Convergence insufficiency (CI) is a common ocular motor disorder which is frequently treated with eye exercises. We have previously shown that CI is more common in persons with Parkinson’s disease (PD) than in an age-matched sample of people who do not have the disease. The purpose of this study was to determine if vergence performance could be altered with convergence training in individuals with PD.

Methods : Fourteen individuals without dementia having both PD and CI were assigned 30 minutes per day, 5 days per week of convergence training exercises to be done at home. Phoria, near point of convergence (NPC) and positive fusional vergence (PFV) were measured at baseline and then following 1 month and 2 months of convergence training. Convergence Insufficiency Symptom Survey (CISS) scores, although not a main outcome measure of this study, were also determined.

Results : Of the 14 participants who started training, 6 individuals (43%) dropped out prior to the one month visit, 8 individuals (average age 70.4 ± 7.2 yrs; 2 female) completed 1 month of training and 6 of those completed 2 months of training. Phoria remained unchanged over the 2 month period. NPC decreased in 6/8 participants after one month. Average NPC changed from 15 to 13 cm after 1 month (N=8) and from 16 to 10 cm after 2 months (N=6). PFV was increased after one month in 8/8 people. The average change from baseline in the break point was 5 and 7 prism diopters for 1 and 2 months respectively. Repeated measures ANOVA’s of the 6 participants who completed 2 months of training indicated there were significant main effects of training time for both NPC (F=6.84, df=17; p<0.008) and PFV (F=3.96, df=17; p<0.04). CISS scores were variable and did not change significantly over the 2 months.

Conclusions : Ocular vergence function can be altered following 1-2 months of convergence training in individuals with PD who also have CI. These promising results suggest that a clinical trial to determine efficacy of convergence training as a treatment modality in these patients should be considered. Similar to other exercise programs, motivation and support will be important for compliance and overall success of such a treatment. Home support in this population may be more satisfactory than office-based training since attending multiple appointments is particularly challenging for them.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.