Immune (food allergy, infection)
Natural Medicine Causes & Treatment of Retinitis Pigmentosa
Retinitis pigmentosa (RP) is a group of genetic eye conditions. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades.
Many people with RP do not become legally blind until their 40s or 50s and retain some sight all their life. Others go completely blind from RP, in some cases as early as childhood. Progression of RP is different in each case.
RP is a type of hereditary retinal dystrophy, a group of inherited disorders in which abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium (RPE) of the retina lead to progressive visual loss. Affected individuals first experience defective dark adaptation or nyctalopia (night blindness), followed by reduction of the peripheral visual field (known as tunnel vision) and, sometimes, loss of central vision late in the course of the disease.
Signs
Mottling of the retinal pigment epithelium with black bone-spicule pigmentation is typically indicative (or pathognomonic) of retinitis pigmentosa. Other ocular features include waxy pallor of the optic nerve head, attenuation (thinning) of the retinal vessels, cellophane maculopathy, cystic macular oedema and posterior subcapsular cataract.
Diagnosis
The diagnosis of retinitis pigmentosa relies upon documentation of progressive loss in photoreceptor function by electroretinography (ERG) and visual field testing. The mode of inheritance of RP is determined by family history. At least 35 different genes or loci are known to cause "nonsyndromic RP" (RP that is not the result of another disease or part of a wider syndrome). Genetic counselling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing. RP combined with progressive deafness is called Usher syndrome.
RP and Autoimmune Disease
There is seems to be an autoimmune component to RP. This is good news for sufferers who have no family history of the condition. And it may also means that treatment can now be directed towards sedating an overactive immune system wither with pharmaceutical drugs or with Complementary and Alternative Medicine (CAM)
Research unveiled at The Second International Conference on Cortisols and Anti-Cortisols reported that retinitis pigmentosa (RP) is composed of two separate diseases -- one genetic and the other autoimmune. While the inherited genetic component has no present therapy, the auto-immune condition can be treated with anti-cortisol nutrients and drugs.[1] Increased risk of autoimmune hypothyroidism in patients affected by retinitis pigmentosa.
Abstract
Patients with Retinitis Pigmentosa (RP) show hemeralopia, restricted field of vision and reduced visual acuity, owing to the degeneration and proliferation of photoreceptors and of retinal pigment epithelium. The prevalence in Italy is 1 :4,000. A certain number of syndromic associations have been described, and, in particular, also that with hypothyroidism, but very few cases have been studied. We describe a family of 40 people, spanning four generations, in which we have recorded the presence of autosomic dominant RP, associated with autoimmune hypothyroidism or with circulating antithyroid autoantibodies (ATA), currently considered as the expression of active autoimmune thyroiditis or a risk factor for this complaint. We measured, in all members, TSH, FT3, FT4, antithyroglobulin and antithyroperoxidase autoantibodies. A fundus oculi examination was performed in every subject, as well as a careful examine of the anterior region of the neck. A control population of 100 healthy people was also studied. Our data show a higher prevalence of ATA, statistically significant, in the patients with RP and in their relatives, compared with the control population and the data from the literature (13 cases over 40 = 32.5% ; p<0.01).
3 patients with RP and ATA were affected by clinically evident hypothyroidism. 10 patients with ATA were clinically euthyroid ; 8 patients affected by RP did not show circulating ATA at the time of the study.
The interest for the physician in this syndromic retinal distrophy reflects the need, emerging from our data, to test the thyroid function in the subjects with RP and in members of their families, since circulating ATA are considered a risk factor for the development of autoimmune hypothyroidism.[2]
Pigmentary retinal degeneration has been seen in a number of diseases considered to have an immunological basis e.g. Behcet's disease, polyarteritis nodosa, rheumatoid arthritis, multiple sclerosis and Harada's disease.[3] [4]
Antigenicity of retinal neuroepithelium has been well documented. It is known that the cornea, uvea, pigment epithelium of retina and the lens share some common antigens. Uveitogenic nature of retina has been demonstrated in various animal experiments by different workers.[5]Further work has demonstrated that is the photoreceptors in the retina which are antigenic[6] [7]. Various immunoglobulin abnormalities have been described in retinitis pigmentosa. These include rheumatoid factor positivity in the serum in as many as 38% cases and significantly elevated IgM level in the serum[8] [9]Some initial success has been reported in treating cases of retinitis pigmentosa with D-penicillamine[10]. The utility of D-Penicillamine in treating diseases like rheumatoid arthritis and PSS has been well established for sometime now.
These observations have raised interesting possibilities:
- a) Since it is known that autologous 1gM can lyse neuraminidase treated host cell, it has been suggested that naturally occurring cytotoxic antibodies of this class could be important in the process of ageing[11]. However, selective degeneration of visual cells is not a feature of old age, therefore it is difficult to regard retinitis pigmentosa as a product of premature senility, hence the role of raised IgM levels in retinitis pigmentosa remains unclear.
(b) Since the production of IgM is genetically controlled and a large production of cases of retinitis pigmentosa are hereditary in origin, it is possible that individuals with raised IgM are more susceptible to retinal degeneration.
(c) Raised IgM in retinitis pigmentosa may be suggestive of an occult infection especially in view of the suggestion that retinitis pigmentosa may be caused by a slow virus infection [12]. Thus, there is great deal of evidence to suggest that retinitis pigmentosa may be a disease of on autoimmune aetiology. [13]
Complementary Medicine Treatment for Retinitis Pigmentosa
Vitamin A
There is currently no medical treatment that can completely cure retinitis pigmentosa, although the progression of the disease can be reduced by the daily intake of 15000 IU of vitamin A palmitate. Recent studies have shown that proper vitamin A supplementation can postpone blindness by up to 10 years. A study on 1603 patients with retinoisis pigmentosa found treatment with vitamin A palmitate 15,000 IU/day. Evidence is presented to support the idea that patients with a projected cone amplitude of 3.5 microV or greater at age 40 (about 25% of our patient population with typical retinitis pigmentosa) would be expected, on average, to retain some useful vision for their entire lives without treatment. Knowledge of the amount of remaining cone function in the ERG often reduces patient anxiety and helps patients plan for their future. [14]
Vitamin E and Vitamin A
Vitamins A and E in the treatment of retinitis pigmentosa This study, from the Massachusetts Eye and Ear Infirmary, Boston, was a randomised, controlled, double-masked trial of vitamin A and vitamin E supplementation in 601 patients with retinitis pigmentosa. The patient, aged 1849 years, were randomly assigned to receive 15,000 IU of vitamin A (as retinyl palmitate), 400 IU of vitamin E, both vitamins, or a placebo (containing trace levels of the vitamins) daily for four to six years. The principal outcome measure was cone electroretinogram amplitude, an objective measure of retinal function.
Patients receiving vitamin A (with or without vitamin E) showed a slower rate of decline in retinal function, as measured by cone electroretinogram amplitude, in comparison with those not receiving vitamin A. Vitamin E showed no effect in the group as a whole. However, in a subgroup of patients with initially better retinal function, those receiving vitamin E showed a faster rate of decline in retinal function than those not receiving the vitamin.
"These results support a beneficial effect of 15,000 IU/ d of vitamin A and suggest an adverse effect of 400 IU/ d of vitamin E on the course of retinitis pigmentosa." The authors recommend that "most adult patients with the common forms of retinitis pigmentosa" should take a vitamin A supplement under medical supervision and that these patients should avoid the use of high-dose vitamin E supplements. [15]
Taurine, Diltiazem and Vitamin E
Treatment with taurine, diltiazem, and vitamin E retards the progressive visual field reduction in retinitis pigmentosa: a 3-year follow-up study. The purpose of this study to assess the effect of the formula taurine/diltiazem/vitamin E on the progression of visual field loss in retinitis pigmentosa.
A double blind, placebo controlled study in 62 patients: visual field threshold values were obtained in a Humphrey Field Analyzer from centre (30 degrees) and periphery (30-60 degrees), every 4 months during 3-year follow-up. Data were analysed by univariate regression, with slopes obtained from the best fit lines. Based on slope values, three groups of patients were identified as those showing negative, positive, or zero slope: > or = 1 to < or = +1. In controls (32 patients), at central area, the distribution in negative, zero, or positive slope was, respectively, 16 (50%), 11 (35%), and 5 (15%). In the treated group (30 patients) this distribution was 6 (20%) negative, 17 (53%) zero, and 7 (23%) positive slope. In periphery, 16 control patients were distributed as 11 (69%) negative, 4 (25%) zero, and 1 (6%) positive slope. In the treated group (17 patients), the distribution was opposite: 1 (6%) negative, 7 (41%) zero, and 9 (53%) positive slope. Nineteen patients receiving treatment up to 6 years showed similar distribution by slope values. Eight out of 9 patients switched from placebo (2 years) to treatment (2-3 years), showed improving changes in their slope values. A beneficial effect of the treatment decreasing the rate of visual field loss was observed, likely through a protective action from free radical reactions in affected photoreceptors.[16]
Reported effects of non-traditional treatments and complementary and alternative medicine by retinitis pigmentosa patients.
BACKGROUND:
Benefits of complementary and alternative medicine (CAM)-related interventions have been demonstrated for patients with chronic, systemic diseases in which stress, anxiety and disability are prevalent. Subjects with retinitis pigmentosa (RP) commonly indicate that they have 'good' and 'bad' vision days, stating that stress causes a decrease in vision and that vision improves when the stress is alleviated. We assessed CAM use by RP patients and its perceived effectiveness. METHODS: We enquired about nine CAM areas: meditation, mind-body therapies, yoga, movement therapies, energy therapies, acupuncture, massage therapy, spirituality/religion and herbal therapies/aromatherapy. Ninety-six RP patients with any level of vision completed an anonymous internet survey.
RESULTS:
Ninety-five per cent of respondents tried at least one of the nine CAM areas. Seventy-five per cent have used nutritional supplements, including lutein (47 per cent), bilberry (32), vitamin A palmitate (36) and docosahexaenoic acid (23 per cent). Some tried meditation (47) and yoga (31 per cent). Stress and anxiety levels were reported as improved in 93, 92 and 87 per cent of those who used yoga, meditation and mind-body therapies, respectively. Many of those who tried mind-body therapies (40) or acupuncture (50 per cent), used it with a desire to fight RP. Vision was subjectively affected in 65 per cent of acupuncture users and from 20 to 35 per cent of the users of the other CAM areas. Those who indicated that their vision was affected by at least one type of CAM (35 per cent) were statistically significantly more likely to require magnification to read (that is, they had lost more vision and RP had progressed), than those who did not believe vision was impacted (59 versus 84 per cent).
CONCLUSIONS:
RP patients are using CAM and are experiencing some impact on vision and physical/emotional well-being. Clinicians and researchers should be aware of its use. Clinical trials with CAM interventions are necessary to attempt to validate these findings.[17]
Scientists at the Osaka Bioscience Institute have identified a protein, named Pikachurin which they believe could lead to a treatment for retinitis pigmentosa.[18]
In a study published in the journal Nature researchers working with mice at the University College London Institutes of Ophthalmology and Child Health and Moorfields Eye Hospital transplanted mouse stem cells which were at an advanced stage of development, and already programmed to develop into photoreceptors, into mice that had been genetically induced to mimic the human conditions of retinitis pigmentosa and age-related macular degeneration. These photoreceptors developed and made the necessary neural connections to the animal's retinal nerve cells, a key step in the restoration of sight. Previously it was believed that the mature retina has no regenerative ability. This research may in the future lead to using transplants in humans to relieve blindness.[19]
Bilberry and retinitis pigmentosa
Loss of dark adaptation is characteristic of retinitis pigmentosa. Studies have shown that dark adaptation is greatly improved by bilberries (European blue berries).
Electrical Currents and Zinc supplementation and retinitis pigmentosa
Zinc supplementation can slow but not stop vision loss. A study by Michael and Allen used nutrients and zinc. They also applied 200 microamperes of electricity ±9 volts square wave, 10 cycles/sec.) to closed eyelids. Acuity improved or was stabilised for 15 out of 25 macular degeneration patients, monitored for five years. Other studies have shown that the application of weak electrical currents to the eye has positive benefit in macular degeneration and other conditions.[20]There seem to be no known adverse effects from using microamperage electric current on the eyes. Our use of 200 micro amperes, ±9 volts at 10 cycles per second on moist dosed eye lids, produces only a sensation of flickering light.
Anti-Cortisols May Offer New Hope For Retinitis Pigmentosa
LAS VEGAS, NV -- November 17, 1997-- New research revealed at The Second International Conference on Cortisols and Anti-Cortisols reported that retinitis pigmentosa (RP) is composed of two separate diseases -- one genetic and the other autoimmune. While the inherited genetic component has no present therapy, the auto-immune condition can be treated with anti-cortisol nutrients and drugs.
These new findings were disclosed in a study presented by Alfred Sapse, M.D., a leader in cortisol/anti-cortisol research and former director of ophthalmic immunology at Cedars-Sinai Medical Centre in Los Angeles. "RP was previously viewed as an untreatable, solely genetic condition," Sapse said. "By uncovering its auto-immune component, we can attack the disease with a new arsenal of anti-cortisol compounds.
" RP's auto-immune component is believed to be associated with elevated levels of the stress hormone cortisol. Known as the fight or flight stress hormone, cortisol can throw the immune system into chaos and ravage the human body. While it was previously regarded as merely a symptom or marker of serious diseases, high levels of cortisol are now believed to be a major component of such diseases and conditions as RP, AIDS, MS, Alzheimer's, the aging process and several forms of cancer. According to Sapse, RP can be treated initially with a cocktail of anti-cortisol nutritional compounds including vitamin A, zinc, ginkgo biloba and acetyl-L-carnitine, followed by treatment using anti-cortisol/steroidogenesis inhibitor drugs.
The key to treatment of RP with anti-cortisol drugs is the ability to accurately measure when cortisol levels are elevated. In this regard, Sapse has introduced a new 24-hour circadian cortisol chart to accurately measure levels of the hormone in RP patients.
Herbal medicine for retinitis pigmentosa
Carahealth Eye Tonic
This mix contains a blend of herbs known as ophthalmics that treat eye diseases. The herbs are specifically rich in Vitamin A, caretenoids and anthocyanidins. Anthocyanidins, are antioxidants that neutralise free radical damage to the collagen matrix of cells and tissues that can lead to cataracts, glaucoma, varicose veins, haemorrhoids, peptic ulcers, heart disease and cancer. The herbs have been shown in numerous studies to improve night time visual acuity and promote quicker adjustment to darkness and faster restoration of visual acuity after exposure to glare. Ideal for pilots!
Clinical Success in China
Chinese herbal doctors have reported some successful applications of these herbal combinations;
Concha Haliotidis Source: The shell of Halio diversicolor Reeve, H. Gigantea discus Reeve and H. ovina Chemnitz, family Haliotidae.
Indication:
(a). Calm the liver, benefit yin and suppress the sthenic yang: for sthenia of liver-yang or deficiency of yin leading to hyperactivity of yang manifested as dizziness, headache, tinnitus, irritability and insomnia.
(b). Clear away liver-fire to improve visual acuity: For conjunctivitis of liver-heat type; for night blindness; for blurring of vision due to liver-deficiency; for nebula, ointment should be applied topically.
(c). Antacid and analgesic: For stomach ache and regurgitation.
Pharmacological Actions:
(a). Improves eyesight.
(b). Haemostatic.
Fructus Corni Source: The pulp of Cornus officinalis Sieb. et Zucc., family Cornaceae.
Indication:
(a). Invigorate the liver and kidney, supplement the essence and improve visual acuity: For deficiency of the liver and kidney manifested as soreness of the waist and knees, flaccidity of lower limbs, impotence, frequent micturition, sterility, dizziness, tinnitus and blurring of vision.
(b). Astringe and preserve essence: For hypofunction of liver and kidney manifested as emission, enuresis, frequent micturition, metrorrhagia, menorrhagia, spontaneous perspiration, night sweat, collapse with profuse perspiration and dyspnea of asthenic type.
Pharmacological Actions:
(a). Relieving cyclophosphamide-induced leukopenia inmice.
(b). Diuretic and hypotensive.
(c). Inhibiting the growth of Bacillus dysenteriae in vitro.
Colla Cornus Cervi Source: The gelatin made of the antler of Cervus nippon Temminck or Cervus elaphus Linnaeus, family Cerridae.
Indication:
Warming and tonifying liver and kidney, enriching essence and blood. Indicated for impotence, spermatorrhea, aching and coldness in the loin and knees, and metrorrhadia.
Fructus Lycii Source: Fruit of Lycium barbarum L., family Solanaceae.
Indication:
Nourish yin, enrich blood, benefit essence and improve visual acuity: For deficiency of liver-yin and kidney-yin and insufficiency of essence and blood manifested as dizziness, blurring of vision, hypopsia, tinnitus, emission and soreness of the loin and extremities; also for diabetes.
Pharmacological Actions:
It contains vitamins C, B1 and B2, carotene, nicotinic acid, ß-sitosterol and betaine, and can relieve the liver damage induced by CCl4 in mice.
Fructus Schisandrae Source: Fruit of Schisandra chinensis (Turcz.) Baill. and S. sphenanthera Rehd. et Wils., family Magnoliaceae.
Indication:
(a). Benefit vital energy and promote the production of body fluid: For insufficiency of vital energy and body fluid manifested as fatigue, shortness of breath, palpitation, hyperhidrosis (spontaneous perspiration or night sweat), thirst, diabetes, etc.
(b). Astringe lung-energy, relieve dyspnea and cough: For cough and dyspnea of lung-deficiency type, lung-cold type and the type of dificiency of both lung and kidney.
(c). Invigorate kidney to preserve essence: For heart-deficiency syndrome with palpitation, insomnia, and dreaminess. In addition, its powder preparation is used for chronic hepatitis with elevation of serum transaminase.
Pharmacological Actions:
(a). Its decoction exerts bacteriostatic effect on Pseudomonas aeruginosa (1:128), Staphylococcus aureus (1:64), Flexner's bacillus (1:32) and typhoid bacillus (1:8) in vitro.
(b). Schizandrin, one of its active component, can protect the liver from damage.
(c). Enhancing lymphocyte-blastogenesis rate.
(d). Cardiotonic and sedative.
Rhizoma Cimicifugae Source: Rhizome of Cimicifuga heracleifolia Kom., C. dahurica ( Turcz.) Maxim. and C. foetida L., family Ranunculaceae.
Indication:
(a). Expel wind and heat, clear away toxic materials and let out skin eruption: For common cold of wind-heat type, and measles with indistinct eruptions.
(b). Lift up yang-energy: For visceroptosis.
(c). Clear away heat and expel fire: For toothache due to stomach-heat, aphthae and headache.
Pharmacological Actions:
(a). Antipyretic, analgesic and anti-inflammatory. Gastric infusion of its extract (mainly containing ferulic acid) in a dosage of 1.0g/kg can lower the body temperature of normal rats, and relieve the pain elicited by acetic acid in mice.
(b). Inhibiting myocardium, slowing heart rate and lowering blood pressure.
Semen Cuscutae Source: Seed of Cuscuta chinensis Lam., family Convolvulaceae .
Indication:
(a). Invigorate the kidney and supplement essence: For insufficiency of kidney-yang or kidney-essence manifested as impotence, emission, enuresis, frequent micturition, sterility, leucorrhagia, soreness of the loin and knees, tinnitus and deafness.
(b). Soothe the foetus: For deficiency of the liver and kidney manifested as threatened abortion and habitual abortion.
(c). Nourish the liver and improve visual acuity: For blurring of vision and hypopsia due to insufficiency of the liver and kidney.
(d). Benefit the spleen to relieve diarrhea: For loose stools or diarrhea due to deficiency of the spleen and kidney. recently, also used for aplastic anemia and chyluria.
Pharmacological Actions:
(a). Cardiotonic.
(b). Promoting lymphocyte-blastogenesis
Radix Bupleuri Source: Root of Bupleurum chinense DC. and the root or herb of B. scorzonerifolium Willd., family Umbelliferae.
Indication:
(a). Expel the exogenous evil from the body surface, let off heat, and clear away evil heat from shaoyang channel: For common cold with fever, alternating episodes of chilliness and fever, malaria.
(b). Disperse the stagnated liver energy: For stagnation of liver energy with hypochondriac pain, dizziness, mental depression and irregular menstruation.
(c). Life up yang-energy; For visceroptosis.
Pharmacological Actions:
Saikosaponin is the active component.
(a). Increasing the hypnotic effect of barbital in mice.
(b). Analgesic, anti-inflammatory, antitussive and antipyretic.
(c). Decreasing the damage of liver by CCl4 and increasing biliary secretion in rats.
(d). Hemolytic in vitro.
(e). Lowering blood pressure in rabbits and inhibiting the heart of frog and guinea-pigs in vitro.
Fructus Ligustri Lucidi Source: Fruit of ligustrum lucidum Ait., family Oleaceae.
Indication:
(a). Tonify the liver and the kidney, darken the hair and promote the visual acuity: For deficiency of liver-yin and kidney-yin manifested as dizziness, tinnitus, blurring of vision, weakness of the loin and knees, hectic fever, nocturnal emission, alopecia and poliosis. Recently also used for seborrheic alopecia, central retinitis, early cataract, etc.
(b). Tranquilize the mind by nourishing the heart: For insufficiency of heart-yin manifested as insomnia, palpitation and precordial pain. Recently , also used for angina pectoris, hyperlipemia and neurasthenia, especially those of yin-deficiency type. In addition, also used for leukocytopenia, viral hepatitis with yin-deficiency syndrome; its component oleanolic acid for various kinds of hepatitis.
Pharmacological Actions:
(a). Its component oleanolic acid can prevent and relieve cyclophosphamide-induced leukocytopenia in mice.
(b). Enhancing the anoxia tolerance of mice under atmospheric pressure.
(c). Increasing coronary flow in rabbits in vitro.
(d). Relaxing adrenaline-induced vasocontriction in rabbits in vitro.
(e). Lowering the level of blood lipid. During observation on 22 patients receiving treatment with herbal remedy, 4 cases were judged as significant improvement (visual acuity values incremented to over 1.0, and visual angle magnified by over 50 degree), 17 cases other moderate improvement (visual acuity values incremented by over 2 rows, night vision improved, and visual angle magnified). The treatment duration varied from 1 to 4 months. Physicians judged the clinical efficacy to be good or excellent in 95.5%.
For further details contact Carina
Carina Harkin BHSc.Nat.BHSc.Hom.BHSc.Acu.Cert IV TA
[2] Scanneli gG., Dattola l., Pandovanif., Increased risk of autoimmune hypothyroidism in patients affected by retinitis pigmentosa., Journal of endocrinological investigation., 1996, vol. 19, no3, pp. 170-174.
[3] Farrar GJ, Kenna PF, Humphries P (March 2002). "On the genetics of retinitis pigmentosa and on mutation-independent approaches to therapeutic intervention". EMBO J. 21 (5): 857-64.
[4] Online 'Mendelian Inheritance in Man'(OMIM) RETINITIS PIGMENTOSA; RP -268000
[5] Michael. LD. Allen MI: Nutritional SuppIementation electrical stimulation and age related macular degeneration. J. Orthomol Med. 1993:8:168-171.
[6] Allen, MJ: Treating age related macular degeneration. Letter. Optom Vis Sci. 1994: 74:293.
[7] Kurtz JL.: The principles and practice of ocular physical therapy for optometrists, Am J Optomn PubI. 1930.
[8] Wallace L: The treatment of macular degeneration and other retinal diseases using bioelectromagnetic therapy, J Optom Photother. 1997; 3.
[9] Rockland Corporation, 12320 E. Skelly Drive, Tulsa, OK 74128
[10] Tiwari SC, Dhingra K, Khan KM, Malviya AN, Singh M, Gehlot DK. Sjogren's syndrome in association with retinitis pigmentosa-report of an unusual case. Indian J Ophthalmol 1983;31:81-3
[11] Tiwari SC, Dhingra K, Khan KM, Malviya AN, Singh M, Gehlot DK. Sjogren's syndrome in association with retinitis pigmentosa-report of an unusual case. Indian J Ophthalmol 1983;31:81-3
[12] Tiwari SC, Dhingra K, Khan KM, Malviya AN, Singh M, Gehlot DK. Sjogren's syndrome in association with retinitis pigmentosa-report of an unusual case. Indian J Ophthalmol 1983;31:81-3
[13] Tiwari SC, Dhingra K, Khan KM, Malviya AN, Singh M, Gehlot DK. Sjogren's syndrome in association with retinitis pigmentosa-report of an unusual case. Indian J Ophthalmol 1983;31:81-3
[14] Berspon, EL., Long-term visual prognoses in patients with retinitis pigmentosa: the Ludwig von Sallmann lecture., Exp Eye Res. 2007 Jul;85(1):7-14. Epub 2007 Mar 7.
[15] Eliot L Berson et al, A Randomized Trial of Vitamin A and Vitamin E Supplementation for Retinitis Pigmentosa, Archives Opthalmology
[16] Pasantes-Morales H, Quiroz H, Quesada O., Treatment with taurine, diltiazem, and vitamin E retards the progressive visual field reduction in retinitis pigmentosa: a 3-year follow-up study. Metab Brain Dis.. 2002 Sep;17(3):183-97
[17] Kiser AK, Dagnelie G., Reported effects of non-traditional treatments and complementary and alternative medicine by retinitis pigmentosa patients. Clin Exp Optom. 2008 Mar;91(2):166-76
[18] Sato S, Omori Y, Katoh K, et al (August 2008). "Pikachurin, a dystroglycan ligand, is essential for photoreceptor ribbon synapse formation". Nat. Neurosci. 11 (8): 923-931.
[19] MacLaren, RE; RA Pearson, A MacNeil, RH Douglas, TE Salt, M Akimoto, A Swaroop, JC Sowden, RR Ali (2006-11-09). "Retinal repair by transplantation of photoreceptor precursors". Nature 444 (7116): 203-7.
[20] 7.Kurtz JL.: The principles and practice of ocular physical therapy for optometrists, Am J Optomn PubI. 1930.