Assessment And Restoration Of Glaucomatous Visual Function

Objective Vision loss from glaucoma has traditionally been described as loss of “peripheral vision. In clinical,the detection and treatment of glaucoma are always focus on how to slow down the process of the damage of visual field, Little attention was given to the evaluation and protection of other visual function of glaucoma. This study concentrated on the visual function damage in glaucoma, It is mainly about the relationship between glaucoma contrast sensitivity, visual acuity and visual field defects in glaucoma, and the characteristics of microsaccadic eye movement, as well as its relationship with visual function, and ultimately to explore the feasibility of applying visual perceptual learning(VPL) to improve the visual function of patients with glaucoma.Methods 1, We collected 70 eyes of 35 subjects from the Tianjin Eye Hospital,who be in the hospital from May 2012 to May 2013, as glaucoma group. We also collected 34 eyes of 17 age-matched normal people as control group. Contrast sensitivity was measured using the CSV-1000. Visual acuity was measured using the CSV-1000 ETRDS letter chart. Visual fields of the patients were measured using the 24–2 Standard program on the Humphrey Visual Field Analyzer. The t-text was used for comparing between glaucoma group and control group. The Spearman correlation analysis was used for analysing the correlation between different detection methods. A multivariate linear regression was performed to detect which contribute to visual field defects。 2. 20 glaucomatous patients and 15 age-related controls with normal vision gazed at a fixed traget on a computer monitor whilst eye movements were simultaneously recorded using a high-speed eye-tracker system. The microsaccadic eye movements of both eyes were recorded in an order of right to left. A computerized microsaccades component analysis of eye-movement waveforms was developed to quantify the parameters of microsaccades. We calculated the mean amplitude(MA) and mean peak velocity(MPV) of the microsaccades. The differences between groups were evaluated using one-way ANOVA followed by Bonferroni tests. Contrast sensitivity,visual acuity and visual fields of each eye were also respectively detected and compared to microsaccades using Spearman correlation analysis. 3. We enrolled two subjects previously diagnosed with glaucoma and with stable visual fields and well controlled intraocular pressure(IOP). A was given the placebo VPL training. B was given the really VPL training. They are all trained in their computer at home.The study phases included a total of four visits, ie, a baseline visit, a 15 th session visit(visit 1), a 30 th session visit(visit 2), and an end of treatment examination(session 45 visit). Visual acuity and contrast sensitivity function at 3, 6, 12, and 18 cycles per degree spatial frequencies were obtained at every visits for statistical analysis in both groups. Visual field and microsaccadic eye movement were measured before and after study.Results 1. Glaucoma patient group had statistically significant mean contrast sensitivity at all four spatial frequency、visual field、Log MAR visual acuity compared to the control group(p<0.001). The correlations between the visual field mean deviations and the contrast sensitivity(r3cpd=0.527,P<0.001;r6cpd =0.574,P<0.001;r12cpd =0.623,P<0.001;r18cpd =0.404,P<0.01)were higher than the correlation between visual field mean deviations and Log MAR visual acuity values(r=-0.317,P<0.05). The multivariate linear regression found that the MD could be predicted from the 12 cpd contrast sensitivity,R=0.593,P<0.001 sensitivity score 2. According to visual field defects, each of patient’s eyes could be divided into worse eye(WE) and better eye(BE). Both eye’s BE and WE had increased MA and MPV, when compared to normal eye(NE). { P<0.001} However, there is no difference between BE and WE. Neither microsaccades MA nor microsaccades MPV of patient’s eye relates to visual function(P>0.05). 3. Through the training, the visual acuity and contrast sensitivity of A patient was not improved. The visual acuity of B patient was increased by approximately 2 line compared to baseline measurements. The contrast sensitivity had also a corresponding increase. The visual field and eye movements had no significantly change.Conclusion 1. Comparing to visual acuity measurement, the contrast sensitivity has a stronger correlation to visual field. Comparing to the visual field examination, contrast sensitivity test need shorter time by about ten times. Contrast sensitivity test can be used as a relatively efficient, fast, low-cost method for follow-up evaluation of glaucomatous postoperative patients. 2. Microsaccadic eye movements in glaucomatous patients differ from normal-sighted people of a similar age during fixation, providing evidence for a potential new window for looking into the functional consequences of the disease and it might has some reference significance for evaluating the damage of glaucoma. 3. It might be feasible to apply visual perceptual training to improve visual acuity and contrast sensitivity in patients with glaucoma, and need further clinical study to prove it right.