Abstract
Purpose: :
Animal trials showed that 9-cis beta carotene may be efficacious in the treatment of retinitis Pigmentosa (RP). We showed it to improve retinal functions [electroretinography and perimetry] in patients with congenital stationary night blindness [fundus albipunctatus]. We tried to determine whether the same treatment is effective for treating RP patients.
Methods: :
RP patients, who were not genetically selected, were tested in a double-masked, placebo-control, cross-over trial. They were given daily for 90 days 4 X15mg capsules containing powder rich in 9-cis beta carotene or placebo. This was followed by a 90 days washout period and a 90 days cross-over period. At the beginning and end of each period, the patients were tested for best corrected visual acuity and underwent electroretinography using an ISCEV compliant protocol and Goldmann perimetry.
Results: :
Thus far, 12 out of the 34 patients completed the study. Six of them showed significant improvement in both scotopic and photopic ERG. The average changes were 18±12 microvolt and 7±4 microvolt respectively as compared to -1±5 microvolt and -1±3 microvolt in the cross-over, presumably placebo, period (p=0.001, p=0.0003 respectively). The difference in the visual field area was significantly larger in one treatment period [35±45 cm2] than in the other period [0±3 cm2 (p=0.042)]. Six patients showed no ERG or perimetry improvement in both treatment period (p=0.914, p=0.934, p=0.423, respectively). There were no changes in the visual acuity recorded in any of the patients. The baseline scotopic ERG responses were higher in the patients of the patients who improved as compared to those that did not. (78±77 vs., 31±32, p=0.06).
Conclusions: :
9-cis beta carotene seems to be effective for some RP patients. More improvement was observed in patients with better initial visual functions. The treatment had no effect on some patients, probably due to 9-cis beta carotene being unrelated to all the various pathogenic mechanisms of the disease. The results presented here have to be evaluated in patients with genetically selected forms of RP. The optimal dose and persistence of has to be determined.
Clinical Trial: :
www.clinicaltrials.gov NCT00569023
Keywords: carotenoids/carotenoid binding proteins • electroretinography: clinical • retinal degenerations: hereditary