Did you know that an estimated 30% of patients with Parkinson’s disease (PD) experience diplopia (double vision)? According to Parkinson’s News Today, a large longitudinal study determined that diplopia is associated with motor and non-motor-related Parkinson’s symptoms. Ultimately, researchers wanted to understand the prevalence and risk factors associated with diplopia and PD. As a result, researchers suggest that patients with Parkinson’s should be screened for visual symptoms related to their condition. Check out the full study findings published in Movement Disorders Clinical Practice.
Diplopia
According to Harvard Health Publishing at Harvard Medical School, there are two forms of diplopia, which causes someone to see two of a certain object: monocular and binocular. The publication explains that:
Monocular diplopia is double vision in only one eye [which] continues even when the eye is covered [and] does not go away when you look in different directions. Binocular diplopia is double vision related to a misalignment of the eyes. [that] stops if either eye is covered.
Typically, monocular diplopia is caused by keratoconus, astigmatism, dry eyes, retinal issues, cataracts, or a dislocated lens. Alternately, diabetes, myasthenia gravis (MG), extraocular nerve damage, eye muscle trauma, and Graves’ disease can cause binocular diplopia. The condition is usually treatable.
The Research
In this study, researchers were curious as to why vision issues were reported in patients with Parkinson’s disease. So these researchers from the University of Pennsylvania (UPenn) conducted a study over a 5-year period to understand the risk factors associated with diplopia. 26,790 patients with Parkinson’s were surveyed. 9,257 “healthy” individuals were also included. 44.6% of patients were female, while 76.6% of healthy controls were female. All data from these individuals was found using the Michael J. Fox Foundation’s Fox Insight Study.
Next, UPenn researchers offered patients assessments and questionnaires relating to patient outcome, motor skills, movement, non-motor symptoms, cognitive activities, and more. Most included patients completed an average of 5 questionnaires. Researchers discovered that:
- Diplopia was significantly more common in patients with Parkinson’s than in the control group.
- Throughout the study, 28.2% of patients experienced double vision.
- Risk factors included being older (65+), being female, and being non-white.
- Additionally, patients with diplopia were more likely to have had Parkinson’s for a longer period.
- Those with diplopia are more likely to have difficulties with daily activities, as well as both motor and non-motor skills.
Moving forward, researchers suggest that doctors pay closer attention to visual symptoms of Parkinson’s disease.
Parkinson’s Disease (PD)
Altogether, Parkinson’s disease, a progressive central nervous system disorder (CNS), results from dopaminergic neuron death. Normally, neurons in our brain produce dopamine. This helps move messages from the brain to the muscles. As these neurons break down and die, this communication is impaired. While doctors are not sure what causes this neuronal death, many believe that environmental triggers, genetics, and Lewy body formation play a role. Parkinson’s occurs in five stages, progressing from light tremors to a loss of independent living. By the final stage, many patients often develop hallucinations, delusions, or other neuropsychiatric problems. Other symptoms include:
- Tremors or shaking in one or both hands
- Muscle stiffness and rigidity
- Changes in speech, such as slurring or stuttering
- Slowed movement
- Difficulty walking
- Poor balance and coordination
- Postural issues
- Fatigue
