Loss of sense of smell or hyposmia is a common but rarely-noticed symptom that may occur years before the start of motor symptoms, or a diagnosis of Parkinson’s. Also, the effects of Parkinson’s may have an impact on some people’s vision.
Smell
Most people with a reduced sense of smell will not develop Parkinson’s. It may be due to a lack of the mineral zinc, sinus problems, age, or the result of a previous injury. However, for some people it will indicate the start of Parkinson’s.
If you have trouble with smell, consult your doctor.
Why loss of sense of smell occurs in Parkinson’s
For newly diagnosed people with Parkinson’s, 96% will have lost some ability to smell. Little is known about what causes loss of smell. One popular theory is that it relates to the protein ‘alpha-synuclein’, which is found in clumps in the part of the brain affected by Parkinson’s. This region of the brain is also very close to the Olfactory Bulb, which is responsible for our sense of smell.
Parkinson’s and vision
Parkinson’s affects movement that can include movement of the eyes. This may therefore affect vision. Everybody experiences Parkinson’s differently and only some people will experience vision problems. Vision problems may be caused by Parkinson’s medication, the result of ageing, an infection, or another unrelated condition which may need investigating.
Eye problems and vision difficulties for people with Parkinson’s may include:
- Difficulty moving your eyes, especially noticeable when watching fast objects such the ball in a tennis match
- Blurred vision as a side effect of Parkinson’s medication, particularly anticholinergics
- Double vision
- Involuntary closure of the eyelids, excessive blinking or twitching
- Deterioration in visuo-spatial orientation – the ability to judge the space around you or between objects
- Excessive watering of the eyes
- Tired eyes
- Colour and contrast sensitivity due to a lack of dopamine in the eye’s retina. People with Parkinson’s may find it hard to distinguish between shades of the same colour, particularly blues and blue/greens
- Dry eyes, as people with Parkinson’s may blink less often
- Visual hallucinations. This is where they see things that aren’t there, such as flickering lights, objects, people, or animals. It’s more common in those who have had Parkinson’s for a long time. It may be due to the condition itself and partly to the medication that is used to treat it. Older people and those with memory (cognitive) problems are more likely to hallucinate.
Parkinson’s medication and glaucoma
If you have glaucoma, you may have problems with some Parkinson’s medications, such as anticholinergic medication and levodopa. Speak to your GP or specialist and ask them to liaise with an ophthalmologist to determine what is best for your situation.
Useful tips
- See your GP or specialist to check what is causing your vision issues. You may then be referred to an ophthalmologist (a medically trained doctor who specialises in eyes)
- Attend regular eye exams with an optometrist, at least once a year, even if you aren’t experiencing any specific problems with your eyes
- Make sure you have enough sleep
- Check with your optician that your glasses are up-to-date and correct
- For dry eyes, try artificial tears that are available from pharmacies and may help reduce discomfort and dryness
- To reduce your chance of falls due to vision issues, make sure you have good lighting, including a lamp close to your chair, well-fitted carpets so you don’t trip, and good contrast between things to make them easier to see, e.g., dark bathroom floor if you have a white toilet.
Caution
Some eye problems may have implications on your ability to perform some activities and to drive safely. Driving should always be discussed with your doctor if you have any vision problems.
Support for you
- Call the Fight Parkinson’s Information Line on 1800 931 031
- Email: info@fightparkinsons.org.au
- Speak to your doctor or specialist.