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| Evaluation of Structural-Functional Relationship in Glaucoma |
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| 作者：C.K.S. L… 文章来源：Department of Ophthalmology, Caritas Medical Centre, Hongkong 点击数1292 更新时间：2005/6/15 13:30:29 文章录入：cksleung 责任编辑：毛进 |
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| PURPOSE: To evaluate the structural-functional profile between the retinal nerve fiber layer thickness (RNFLT) measured by Optical Coherence Tomography and the visual field (VF) sensitivity.
METHODS: A total of 89 subjects with 27 normal, 21 glaucoma-suspect and 41 glaucoma eyes were included in this cross sectional study. RNFLT was measured by Stratus OCT and VF was examined with Humphrey VF analyzer. The relationships between RNFLT and VF sensitivity, expressed in terms of MD(dB), the unlogged 1/L, the Advanced Glaucoma Intervention Study (AGIS) and the Collaborative Initial Glaucoma Treatment Study (CIGTS) VF scores, were evaluated with linear and nonlinear regression (the 2nd order polynomial, the 3rd order polynomial, the 1st order inverse and the logarithmic) models (only glaucoma patients were analyzed in evaluating the relationships between RNFLT and VF scores). R2 was calculated and the regression models were compared with Alkaike’s Information Criteria and the F test.
RESULTS: Plotting MD against RNFLT, the 2nd order polynomial demonstrated the best fit in the regression analysis whereas linear regression attained the best associations when the perimetry scale was expressed in 1/L. The regression profiles between the AGIS/ CIGTS VF scores and the RNFLT were best fit in the 1st order inverse models (Figure 2). To quantify the rate of change of VF scores in relation to different stages of glaucoma, differentiation of the regression equations were performed. At RNFLT of 81.42, 65.34 and 49.26μm, corresponding to mean RNFLT in the glaucoma group, the AGIS and the CIGTS VF scores increased at the rate of 0.17, 0.27 0.47 and 0.18, 0.28 and 0.49 respectively.
CONCLUSIONS: The description of the structural-functional relationships in glaucoma is dependent on the choice of expressions of VF sensitivity. The curvilinear regression profiles found between RNFLT and the AGIS/CIGTS VF scores / MD support those longitudinal studies in demonstrating that the increased severity of baseline MD or VF scores have higher risks of functional deterioration. For the same degree of structural damage (reduction in RNFLT), the increase in VF scores is more dramatic in the advanced stage of the disease compared to that in the early stage. Therefore, the current AGIS and CIGTS scoring systems are considered to be less sensitive to detect progression in early glaucoma since the steps for progression is defined independent of the stage of the disease. Regression analysis of the structural-functional profile could provide important information in the assessment of the trend and pattern of glaucoma progression.
REFERENCES:
1. Reus NJ, Lemij HG.The relationship between standard automated perimetry and GDx VCC measurements. Invest Ophthalmol Vis Sci.2004;45(3):840-5.
2. Schlottmann PG, De Cilla S, Greenfield DS, et al.Relationship between visual field sensitivity and retinal nerve fiber layer thickness as measured by scanning laser polarimetry. Invest Ophthalmol Vis Sci.2004;45:1823-9.
3. Leske MC, Heijl A, Hussein M, et al.Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. ArchOphthalmol. 2003;121:48-56.
4. Leung CK, Chan WM, Yung WH, Ng AC, Woo J, Tsang MK, Tse KK. Comparison of macular and peripapillary measurements for the detection of glaucoma. An Optical Coherence Tomography study. Ophthalmology. 2005;112:391-400.
5. Leung CK, Chan WM, Hui YL, Yung WH, Woo J, Tsang MK, Tse KK. Analysis of retinal nerve fiber layer and optic nerve head in glaucoma with different reference plane offsets, using optical coherence tomography. Invest Ophthalmol Vis Sci. 2005;46:891-8
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