A Study Of Rayleigh Match In Amblyopia With Central Fixation

Objective:To investigate the red-green color vision function of amblyopia with central fixation quantitatively, and the possible effect of L/M-cone sensitivity in ocular refractive development.Methods:Totally 82 patients were enrolled, they were divided into 3 groups: amblyopia group (43 cases,86 eyes,59 amblyopic eyes), amblyopia history group (24 cases,48 eyes,40 eyes recovered form amblyopia), non-amblyopia group (15 cases, 30 eyes), following examination were done binocularly:cover test, slit lamp examination, direct ophthalmoscope examination, eye fixation, dominant eye determination, Rayleigh matching with the anomaloscope (HMC Anomaloskop Typ 47700) in a dark room, uncorrected visual acuity (UCVA) test, subject refraction and best corrected visual acuity (BCVA) test. All data were analyzed by SPSS 13.0 statistical software among groups to dig out the relation among red-green color vision, refratctive error, BCVA, dominant eye and other factors.Results:Prevalence of color vision deficiency in amblyopia with central fixation was 0.017%. The mean value of R-G match points of amblyopia group was statistically larger than that of non-amblyopia group (p<0.05), but the difference was unrelated to spherical equivalent and the best corrected visual acuity. No difference was found in R-G match range among the groups. In amblyopia group, there was no difference in Raiyleigh match data of unilateral amblyopia compared with those of bilateral amblyopia. For unilateral amblyopia, R-G match range of the amblyopic eyes was markedly wider than that of the healthy ones (p<0.05), without significant difference in R-G match point. There was a smaller but significant increase of R-G match range in the non-dominant eyes of non-amblyopia group compared with dominant eyes (p<0.05). Although the difference for amblyopia history group was similar in R-G match range to that for non-amblyopia group, it did not reach significance at the 0.05 Conclusions:Red-green color vision appears to be normal in amblyopia with central fixation and is transmitted independently of form vision in the P pathway. M cones of amblyopic eyes with central fixation are relatively more sensitive than L cones, which is not related to refractive development obviously. Non-dominant eye has a worse discrimination of mid- and long-wavelength light than the dominant eye, suggesting that visual cortex could suppress the color perception of the non-dominant eye.