| Currently many paper about the relationship between intraocular pressure (IOP) variation and glaucomatous visual field loss have been published. There is accumulating evidence that, at least in some patients, IOP variation is a separate and important risk factor for glaucomatous damage.Part I:The24-hour intraouclar pressure variability parameters as separate risk factors in primary open angle glaucomaObjective:In the first part of the thesis, our research work was planed to evaluate the correlation between mean IOP and common IOP variability parameters. We tried to investigate some particular parameters which could represent IOP variation well and didn’t correlate with mean IOP (for example the parameters such as average real variability or successive vatiation), and evaluated the predictive ability of these24-hour IOP measurements for development or progression of glaucoma and which could be a separate risk factor for glaucomatous damage.Participants and Methods:We randomly chose84study participants those who were diagnosed as primary open angle glaucoma (POAG)in EENT hospital. Standardized testing included24-hour IOP measurements every2h and other tests such as Humphrey full threshold VFs and so on. These participants were divided into early group、medium group and advanced group according to Cup/Disk ratio. We separately summarized measurements of24-hour、day-time and night-time, which included average IOP and various IOP variability parameters (for example standard deviation, cofficient of variability, range, average real variability, successive vatiation and parameters which were independent of mean etc.); analyzed the correlation between average IOP and various IOP variability parameters; investigated the differennce of IOP variability parameters among three goups; evaluated the relative risk factors. We used the statistics ways of ANOVA and Logistic regression analysis, when P (P’)value<0.05means significant difference; when P (P’)value<0.01means highly significant difference. Results:The results showed that24-hour and night-time standard deviation correlated with average IOP (r=0.265, P=0.015; r=0.424, P=0.000), day-time didn’t correlate with average IOP (r=0.197, P=0.073);24-hour, day-time and night-time maximum IOP,24-hour and night-time range correlated with average IOP (r=0.794, P=0.000; r=0.771, P=0.000; r=0.920, P=0.000; r=0.271, P=0.013; r=0.417, P=0.000);24-hour and day-time average real variability,24-hour and day-time successive vatiation didn’t correlate with average IOP (r=0.139, P=0.208; r=0.113, P=0.304; r=0.139, P=0.286; r=0.127, P=0.248), night-time average real variability and successive vatiation correlated with average IOP (r=0.393, P=0.000; r=0.390, P=0.000); all parameters which were independent of mean didn’t correlate with average IOP, scilicet, P value>0.05. The day-time IOP variation of advanced group was distinctly greater than that of early group and medium group (early group was2.14±0.62mmHg, medium group was2.32±0.82mmHg, advanced group was3.16±1.26mmHg; P=0.003, P=0.022); the night-time IOP variation of medium group was greater than that of early group (early group was2.48±0.87mmHg, medium group was3.08±1.57mmHg; P=0.022); the24-hour IOP variation of advanced group was greater than that of early group (early group was2.16±0.49mmHg, advanced group was2.83±1.10mmHg; P=0.016).24-hour successive vatiation, night-time SD independent of mean, night-time ARV independent of mean and SV independent of mean were reliable parameters to predict development or progression of glaucoma and could be separate risk factors for glaucomatous damage.Conclusions:In the first part, average real variability and successive vatiation were the parameters that represent IOP variation, and they were more sensitive than standard deviation and range; The parameters such as SD independent of mean, ARV independent of mean and SV independent of mean were not influenced by average IOP and showed IOP vatiation only, which were reliable parameters to predict progression of glaucoma.Part Ⅱ:The long-term intraouclar pressure variability parameters as risk factors in Rhesus monkey’s chronic ocular hypertensive modelsObjective:In the second part of the thesis, our research work was planed to analyze the data of Rhesus monkey’s chronic ocular hypertensive models. We tried to use different parameters to represent long-term IOP variation and investigate that long-term IOP variation was an important risk factor for progression of glaucoma or not.Participants and Methods:Data were taken from non-human primates involved in studies of experimental glaucoma, including14rhesus macaques’22eyes which were divided into normal group、early group and advanced group according to Cup/Disk ratio. For analysis, the IOP sequences of2-year-follow-up were split into four non-overlapping windows that each lasted six months. We analyzed the correlation between average IOP and various IOP variability parameters of each window; investigated the differennce of IOP variability parameters among three goups; established both early and advanced glaucomatous optic nerve damage model, to clarify the respective relative risk factors and to identify the strongest impact factor. We used the statistics ways of nonparametric tests and COX regression analysis, when P (P’)value<0.05means significant difference; when P (P’)value<0.01means highly significant difference.Results:The results showed that SD independent of mean, ARV independent of mean and SV independent of mean didn’t correlated with average IOP in four windows (P value>0.05) while others strongly correlated with average IOP, and the strongest parameter was the maximum IOP (r=0.956, P=0.000; r=0.920, P=0.000; r=0.952, P=0.000; r=0.878, P=0.000). The overall average IOP and variation had no difference between normal group and early group (P value>0.05), but early group had more days of that IOP was in a higher level than normal group in the beginning (normal group was45.04±15.45%, early group was66.37±11.04%; P=0.028); the overall average IOP、range and variation were significantly different from those of normal group and early group, and the data had greater extent of dispersion than that of normal group (P value<0.05). In the early stage of glaucoma, range of IOP was the most important factor impacting the progression of disease (HR1.067,95%CI1.024-1.113, P=0.002); in the advanced stage of glaucoma, average IOP was the most important factor impacting the progression of disease (HR1.302,95%CI1.118-1.515, P=0.000).Conclusions:In the part, long-term IOP variation wasn’t an independent risk factor which caused the glaucoma progression. Average IOP and variation had combined effect to ultimately cause the glaucomatous optic nerve damage, both of which were risk factors. In addtion, the role of average IOP and IOP variation at different stages in the promotion of disease were not the same. The results showed that it was necessary to use different parameters in the long-term IOP fluctuation which could compensate for the lack and thus better reflected the characteristics of long-term IOP fluctuations. |
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