by Cathy Stern, OD, FCSO, FCOVD, FNORA
A common treatment for amblyopia or diplopia is to patch the stronger eye with a fully occlusive “pirate” patch.
While patching is a well-established treatment, it’s one I would personally like to see us do away with completely.
The visual system is designed to converge and sum two images and to process both central and peripheral visual stimuli in different ways. Peripheral vision, for example, is important for posture, balance and spatial relationships. A dark patch eliminates all of that critical peripheral information and completely changes how an individual processes and understands information. Additionally, it doesn’t teach the brain to see binocularly.
Patching is most problematic for treatment of sudden-onset diplopia caused by a head injury. It is not at all uncommon for a patient experiencing double vision after a head injury to be told to wear a fully occlusive patch for a while, and the problem will “go away” within 6 months. However, patching these patients can actually worsen spatial attention and should not be used before an evaluation for spatial neglect.
Every day in my practice, I use alternatives to full-occlusion patching that I would recommend clinicians consider.
If a patient is seeing double, do not patch! Consider sectoral, translucent patching instead. For example, you can leave some of the periphery open with binasal occlusion (tape on the inner portion of both lenses of the glasses). The taped area could be wide or narrow (or wide on one eye and narrow on the other). In any case, this preserves peripheral vision. The lower portion of the glasses can be taped if the double vision occurs only on downward gaze. These approaches can help patients tremendously with walking and balance.
If a patient has amblyopia, try Bangerter filters or foils (Fresnel Prism and Lens Co./Bernell). These are graded, translucent filters that adhere to one spectacle lens and come in a range of translucencies, from something like thick wax paper to nearly clear. Filtering produces diffuse image defocus. This takes away the strong central image in the better seeing eye to force the weaker eye to work more (the goal of patching), while also maintaining peripheral vision and promoting eye teaming. Bangerter filters have been shown to promote binocular summation (Chen et al.) and improve parent and child acceptance of the treatment (PEDIG) because they are associated with less social stigma, less difficulty performing visual tasks while using them and fewer complaints from the child.
Limit amblyopic patching. If you must use an occlusive patch for someone with amblyopia, consider patching just a few hours a day, and not at school or work.
In presbyopes who are suffering from visual symptoms after a concussion, stroke or other brain injury, switch to separate single vision lenses for various tasks (distance, near, computer) until the problems resolve. Many patients can’t tolerate progressive lenses after an injury, but they may be more heavily dependent on nearpoint correction.
Some colleagues may disagree with these treatment approaches. I offer these strategies in the hope that they can help you reduce symptoms and maintain binocularity for your patients, but I welcome your thoughts and experiences. Please share your comments here on the blog.
Chen Z, et al. Invest Ophthalmol Vis Sci. 2014;doi:10.1167/iovs.14-15224.
Houston KE, et al. Optom Vis Sci. 2017;doi:10.1097/OPX.0000000000000976.
Pediatric Eye Disease Investigator Group, et al. Ophthalmology. 2010;doi:10.1016/j.ophtha.2009.10.014.
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Cathy Stern, OD, FCSO, FCOVD, FNORA, is a developmental and behavioral optometrist with specialized training in learning-related vision problems, vision rehabilitation, computer vision syndrome and sports vision training. She maintains a private practice in Canton, Mass., limited to the diagnosis of developmental and behavioral vision problems and treatment of children and adults with vision therapy and vision rehabilitation.
Disclosure: Stern reports no relevant financial disclosures.
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