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Retinitis pigmentosa typically begins with the degeneration of rods and night blindness in youth, with the later destruction of cones and the loss of daytime vision. It is believed Retinitis Pigmentosa (RP) is due to a genetic imperfection that causes an incorrect protein to be supplied to the retina and also a vitamin A deficiency.

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Gradually the photoreceptor cells die, and vision is lost over time. RP usually affects both the eyes and typically progresses toward the central visual field. In 2004 a study in the journal Ophthalmology looked at electrical currents and RP. The following was stated:

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Retinitis pigmentosa results from outer retinal degeneration. This causes the outer portion of the inner anatomical retina (outer retina), composed primarily of photoreceptor outer and inner segments and their cell bodies, to become damaged, the inner portion (inner retina), comprising the remaining bipolar, horizontal, amacrine, and ganglion cells and nerve fibre layer, can be substantially spared. The presence of these relatively intact remaining retinal layers has led investigators to study the effect of electrical stimulation on these structures to improve vision. (5)

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RP affects the back side of the retina, where the photoreceptors are, including the rods and the cones. The portion of the retina closest to the front side of the eye, which includes the bipolar, amacrine, horizontal and ganglion nerve cells, is usually spared. So, experiments in electrical stimulation were undertaken to see if vision could be improved. Following animal experimentation, the researchers moved to clinical trials. The conclusion:

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Visual function improvements occurred in all patients and included unexpected vision improvements in retinal areas distant from the implant. 

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Electrical stimulation improved vision for patients with retinitis pigmentosa. Pulsed electromagnetic field therapy has also been found helpful. A 1990 study in the journal “Eye” entitled “Decreased Choroidal Blood Flow Associated with Retinitis” found the following:

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The light sensitivities in pairs of eyes of four of the patients differed substantially and in all cases the eye with the better visual performance had the higher ocular pulsatile blood flow. It is concluded that relative choroidal ischemia (insufficient blood supply to the vascular layer of the eye) is closely associated with visual loss and pigment cell degeneration in patients with retinitis pigmentosa….

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The Conclusion:

In view of the observations that substantial loss of PBF (pulsatile blood flow) was found in eyes of RP patients with partial visual loss, it would be logical to evaluate the therapeutic action of increased ocular blood flow on the course of retinal degeneration in RP patients that have not yet suffered severe visual loss. This rationale is supported by the observation that in individual patients the loss of blood flow was greatest in the eye with the poorer visual performance. (6)

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This being the case, it is encouraging to find that PEMF plays a big role in increasing microcirculation, as was noted in the study looking at the effects of PEMF on ocular hydrodynamics (i.e. the flow of fluid in the eye):

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Research evaluated the possible mechanisms for improvement seen in retinal function. The effectiveness of PEMF therapy is not the same in all patients. The benefits from PEMF treatment for 15-30 min usually last only for 8-10 days, consistent with the time to renew rod pigments in the retina. In addition, visual examination of the back of the eye after electromagnetic treatment reveals dilation of the capillaries. Hence, one conclusion is that the favourable effect of PEMF therapy was from improvement of microcirculation. They found that retinal circulation gradually increased from arterioles to capillaries and venules. It appears that the authors concluded that the conditions for retinal rod pigment restoration in the central area of the retina are less favourable than in its peripheral areas. Therefore, the therapeutic effect in patients with loss of vision in the central area of the retina will occur after a greater number of PEMF stimulation sessions. (7)

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In a situation where cell damage has occurred, it is critical to get optimal performance out of the remaining cells. Cells perform well when they are energized with Adenosine Triphosphate (ATP), which is generated in the Mitochondria. ATP is the battery of cells providing the energy for them to operate, no matter what their function. PEMF stimulation has been shown to improve mitochondrial function and ATP production in several studies. [For more information on this, see our article, The Science of Energy in the Human body].

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The fuel for ATP production is derived from oxygen and nutrients delivered to the cells by the blood. Therefore, improving microcirculation in bringing oxygen and nutrients to the cells is critical for this process to occur. [For more information on this, see our article, Optimizing Blood Flow with PEMF].

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Photoreceptor regeneration

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For retinitis pigmentosa sufferers, photoceptor regeneration is critical. In a recent report entitled Spontaneous Regeneration of Human Photoreceptor Outer Segments, the authors stated the following:

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Photoreceptors are damaged in many common eye diseases, such as macular degeneration, retinal detachment, and retinitis pigmentosa. The development of methods to promote the repair or replacement of affected photoreceptors is a major goal of vision research. In this context, it would be useful to know whether photoreceptors are capable of undergoing some degree of spontaneous regeneration after injury. We report a subject who lost retinal function in a wide zone around the optic disc, giving rise to massive enlargement of the physiological blind spot. Imaging with an adaptive optics scanning laser ophthalmoscope (AOSLO) showed depletion of cone outer segments in the affected retina. A year later visual function had improved, with shrinkage of the enlarged blind spot. AOSLO imaging showed repopulation of cone outer segments, although their density remained below normal. There was a one-to-one match between sites of formerly missing outer segments and new outer segments that had appeared over the course of the year’s recovery. This correspondence provided direct morphological evidence that damaged cones are capable, under some circumstances, of generating new outer segments. (8)

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The conclusion of the study is encouraging:

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In humans with retinitis pigmentosa, AOSLO imaging has shown that ciliary neurotrophic factor can slow the rate of outer segment loss. With this report, we provide direct morphological evidence, based on before-and-after imaging of the same retina, that human outer segments can regenerate spontaneously. Normal photoreceptor outer segments undergo incremental renewal on a daily basis to replace membrane discs that are shed from their tips. The spontaneous restoration of outer segments in our subject may have harnessed this intrinsic mechanism, much like a new toenail can grow after one is lost from trauma. Determining the mechanisms that control outer segment renewal, and learning how to activate this process when necessary, may be useful for treatment of vision loss incurred by loss of outer segments.

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While this research is in its preliminary form, and the search for mechanisms that control renewal it is ongoing, it is interesting to note how PEMF has been found to help with neural regeneration in other areas. A NASA PEMF neural stem cell stimulation study found the increased production of growth factors that would facilitate nerve regeneration:

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The ability to use time varied electromagnetic fields (TVEMF) to control and proliferate rate, directional attitude, and molecular genetic expression of normal human neural progenitor cells has been demonstrated….

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One may use this electrical potentiation for a number of purposes, including developing tissues for transplantation, repairing traumatized tissues, and moderating some neurodegenerative diseases and perhaps controlling the degeneration of tissue as might be effected in bioelectric stasis field. (9)

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PEMF effectively provides a 50% improvement in the growth of nerve cells in a process called nerve sprouting in a laboratory setting. In live animal studies, high-intensity PEMF produced a 22% rate of nerve regeneration. (10)

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The combination of exciting studies on the regeneration of photoreceptors with studies demonstrating the use of PEMF in neural regeneration provides hope for sufferers of diseases like retinitis pigmentosa and other eye diseases.