Abstract
Purpose::
Study the percentage of refractive errors in retinitis pigmentosa related to errors found in a healthy control group.
Methods::
Our court study comprend 246 patients (492 eyes) , mean age 48 (age range 18-78) affected by retinitis pigmentosa. This study excluded patients with corneal distrophy, diabetic retinitis and other eye diseases. Ametropy's value were analysed by the use of an auto-refractometer (ACCUREF-8001-SHIN-NIPPON) followed by keratometer, bcva, tonometry,electrofunctional tests and retinal inspection. Spherical refractive errors were expressed in spherical equivalents by adding one half the cylindrical value to the spherical value.The patients with RP were separated in groups according to age (18-36, 37-54, 55-78) and to the refractive error type (**).The main refractive error, standard deviation, Student t-test, were used to construct normal curves for the different groups of patients and they were compared to a healthy groups of 230 people, age and sex matched.
Results::
This study established that 93% of eyes (457) affected by RP show a refractive error. Myopia was found in the 79% of the eyes (361), associated in the 60% with withintherule astigmatism (217); the 10% of them (46) were affected by hypermetropy and 4% (3) by astigmatism greater than 2,5 D.The refractive errors of the patients group relative to spherical form range from +5 D to -17 D.The 7% of eyes (35) weren't affect by refractive errors.
Conclusions::
Refractive errors on 492 eyes of patients affected by RP show high myopic and astigmatic peaks.By comparing these data to those relative to a control group ,it can be said that refractive errors are 5:1 in eyes affected by RP. Our results are similar to those reached by G.A. Fishman with his study "Refractive errors of retinitis pigmentosa patients" done in 1978. Therefore we can say that the myopia and the astigmatism in the patients affected by RP are typical of this illness and are not due to other factors. **myopic <3D, myopic between 3 and 6D, myopic >6D, hypermetropic and astigmatic >2,5D
Keywords: retina • retinal degenerations: hereditary • visual acuity