Choosing the right Deep Brain Stimulation (DBS) programming can be a challenge for people with Parkinson’s disease. There are lots of variables and side effects to figure out. During my recent deep brain stimulation (DBS) recovery period I had blurred vision that in hindsight, may have been due to a combination of reasons including a side effect of DBS stimulation, a result of a particular program setting, the misfortune of a weakened post-surgery immune system, or a combination of all three. I have felt like a detective trying to clarify which blur is the culprit!
In DBS, the neurosurgeon drills a hole through the skull to implant a thin metal electrode in the subthalamic nucleus (STN) or, less often, the globus pallidus (GPi). The electrode is connected to a computerized pulse generator, which is implanted under the skin in the chest. A movement disorder specialist creates a stimulation program using a combination of electrode settings. Stimulation side effects in DBS can cause slurring of speech, blurred vision, and numbness in the skin that may lessen with adjustments to the neurostimulator.
Researcher and deep brain stimulation specialist Sierra Farris lists blurred vision as one of the most common side effects when stimulating in or near typical brain targets for PD.
Blurred vision is also discussed in “Deep Brain Stimulation Programming for Movement Disorders,” by Ioannis U. Isaias and Michele Taglianti, in Deep Brain Stimulation in Neurological and Psychiatric Disorders edited by Daniel Tarsy, Jerrold Lee Vitek, Philip Starr, and Michael Okun. “Diplopia [double vision], blurred vision, and abnormal eye movements may occur in patients with STN DBS. These are not symptoms usually seen in PD and clearly suggest current diffusion beyond the therapeutic target toward the fibers of the oculomotor nerve [the third cranial nerve], which sweeps medially, ventrally and posteriorly to the STN.”
In 2013, I had surgery to treat the left side of my body, (unilateral, one-sided DBS). I did not experience any vision symptoms in that surgery.
My three types of vision blurs
In 2017, I had a second surgery to treat the tremor on the right side of my body, (bilateral, two-sided DBS). DBS 2 brought me the feeling that my vision was slightly blurry. That sensation, depending on the calendar day, may have had three origins.
The program blur
Eleven weeks post surgery for DBS 2, I tried a programming option called interleaving and I experienced a scary change in vision when the program was cranked up high enough to calm my tremor. The sensation was like a double-vision inability to focus. My doctor immediately lowered the setting of the program affecting my vision. The adjusted setting eliminated the blur, but consequently, no longer eliminated my tremor.
The stimulation blur
Twelve weeks after DBS 2 surgery, my movement disorder specialist took me off the interleaving program, and turned down the programming on the side that had the initial DBS, and my eyesight gained a little clarity. I felt better.
The Overlapping Paths of Bilateral Stimulation
My movement disorder specialist, and other professionals in deep brain stimulation recognize that in going from unilateral to bilateral DBS, the second DBS can be problematic. DBS programming may have been perfectly set up for unilateral DBS, but the slight electrical overlap created by bilateral surgery may interfere with effectiveness.
The eye-infection blur
Twelve weeks after DBS 2 surgery, an ophthalmologist diagnosed an eye infection that caused my eyes to redden, blur, and burn. The infection worsened, was later diagnosed as pink eye, which can also have the side effect of blurry vision. At first, I was given an ophthalmic ointment that seemed to compound the feeling of hazy vision. I felt like I was looking through glass smeared in Vaseline. After 11 days of eye discomfort, the doctor changed my ophthalmic ointment to a solution of different antibiotics. Within hours, the redness dissolved, and the haze lifted.
My blurred vision has vanished with reduced stimulation in programming, a new DBS program, and new ophthalmic ointment for infection, and life is looking up.