Due to lack of the practical technique to measure the biomechanical properties of the ocular cornea in vivo, clinical ophthalmologists have some difficulties in understanding the deformation mechanism of the cornea under the action of physiological intraocular pressures. Using Young's theory analysis of the corneal deformation during applanation tonometry, the relation between the elasticity moduli of the cornea and the applanated corneal area and the measured and true intraocular pressures can be obtained. A new applanation technique has been developed for measuring the biomechanical properties of the ocular cornea tissue in vivo, which can simultaneously acquire the data of the applanation area and displacement of the corneal deformation as well as the exerted applanation force on the cornea. Experimental results on a rabbit's eyeball demonstrated that the present technique could be used to measure the elasticity moduli and creep properties of the ocular cornea nondestructively in vivo.
The occurrence of high intraocular pressure (IOP) after vitrectomy for diabetic retinopathy (DR) is related to many factors, including the type and stage of DR, macular detachment, surgical methods, and the type of ocular tamponade. Early high IOP occurred mainly due to laser photocoagulation, inflammatory response, improper ocular tamponade, residual viscoelastic agents and ciliary body dysfunction. In addition to the above reasons, early-middle stage high IOP is also related to tamponade gas expansion peak, encircling scleral buckle and hyphema. The major reason for middle-stage high IOP is hyphema and silicon oil in anterior chamber. The reasons for late-stage high IOP are glaucoma, silicone oil emulsification, long-term use of glucocorticoid, and iris incision closure. Most high IOP can be controlled by proper treatment such as stopping use of glucocorticoid, anti-glaucoma eye drops and surgeries. But there are still a small number of patients with unexplained refractory high IOP, the mechanism need to be further explored.
At present, there are few in vivo experimental studies on anterior chamber flow field, and the relevant technologies are not mature. This study explores the experimental method and key techniques of particle image velocimetry (PIV) for the in vivo measurement of anterior chamber flow field with slow flow velocity in the rabbit with acute intraocular hypertension. The experimental process can be divided into three parts: model construction of rabbit eye with acute intraocular hypertension, in vivo eyeball preparation, and PIV setup. The following key techniques were mainly investigated: the optimal injection strategy of fluorescent particles and the correction strategy for image acquisition errors caused by the effects of image refraction and respiration. The results showed that the best injection method was that 15 μL of fluorescent particles solution was slowly injected into the anterior chamber through the lower part of iris and then the rabbit was released and waited for 13 h. In this way particles were completely distributed in the anterior chamber with the help of the aqueous humor circulation, and then in vivo PIV experiment could be performed. The eyeball should be covered with a square flume filled with ultrasonic coupling gel for the sake of imaging during the experiment. The Maximal Information Coefficient algorithm could be applied to correct the measured results before post-processing calculation. The results indicated that feasible injection strategy of fluorescent particles and the correction strategy for image acquisition are critical to obtain nice experiment effects for the in vivo PIV measurement of anterior chamber flow field in the rabbit with acute intraocular hypertension.
Objective To explore the diagnostic value on 24 hour monitoring of intraocular pressure (IOP) for primary open angle glaucoma (POAG). Methods A prospective study was applied, and a total of 372 subjects through January 2012 to May 2015 for 24 hour IOP monitoring were collected successively, including 137 subjects (271 eyes) with glaucoma (glaucoma group) and 235 subjects (470 eyes) with non-glaucoma (Control group). Data was analyzed using SPSS 13.0 software, and the Kappa statistics was used to evaluate concordance between 24 hour monitoring of IOP and gold standard for POAG diagnosis. Results The mean value of IOP at all monitoring period in glaucoma group was significant higher than that in the control group (P < 0.001). The peak of IOP occurred at 6:00 am and 10:00 in the glaucoma group, and the fluctuation value of IOP in women patients at night (especially at 22:00 pm) was higher than that of men (t=2.064, P=0.04). The sensitivity and specificity of 24 hour IOP monitoring for POAG were 97% and 78.7%, respectively, and with a high consistency comparing to the result of gold standard for POAG diagnosis, with the Kappa values of 0.707 (P < 0.000 1). Conclusion 24 hour IOP monitoring is efficacy and convenient tool, which can be applied alone or combined with other tools to assist early diagnosis patients who are suspected with POAG, so as to improve the diagnostic accuracy.
Objective To observe the changes of electroretino gram(ERG) in temporary traumatic ocular hypotension and to detect the possiblem echanism. Method The rabbit model with ocular hypotenstion was made. At the 2nd, 4th, 8th, 16th week after trauma, the ocular tension and ERG was examined. Result Amplitude of b wave in treated group was 2.5 times as high as that in the control at the 2nd week after trauma, and then decrease to 1.5 times as high as that in the control at the 16th week. Conclution Higher amplitude of b-wave of ERG in rabbit with ocular hypotension may be related to blood circulation congestion, which might lead to accumulation of the metabolic toxin. (Chin J Ocul Fundus Dis，2004，20：189-191)
Objective To observe the clinical characteristics of steroid-induced ocular hypertension (SIOH) in patients with uveitis, and explore the relationship between its clinical phenotype and gene polymorphism. Methods A retrospective case-control study. From July 2019 to December 2020, 576 patients with uveitis who were treated with glucocorticoid eye drops in Tianjin Medical University Eye Hospital were included in the study. Among them, there were 175 confirmed glucocorticoid responders (SRs) and 401 glucocorticoid non-responders (NRs). Seventy cases of SRs (age ≥18 years) using 1% prednisone acetate eye drops were selected as the experiment group and 64 cases of NRs were selected as the control group. The polymorphism of rs2523864 and rs3873352 of human leukocyte antigen complex group (HCG) 22 gene were detected by Sanger sequencing. To observe the clinical characteristics of SIOH after the use of glucocorticoid eye drops, and the correlation between rs2523864 and rs3873352 and the occurrence of SIOH. Differences among groups were compared with the Chi-square test or Fisher's exact test. The correlation between the occurrence of SIOH and the range of intraocular pressure increases after glucocorticoid use and the rs2523864 and rs3873352 loci were compared using the odds ratio (OR) and its 95% confidence interval (CI). Results SIOH occurred in 175 (30.4%, 175/576) of 576 patients. Among them, there were 96 males (54.9%, 96/175) and 79 females (45.1%, 79/175); the average age was 33.64±17.40 years. Steroid high responders (HRs) and steroid moderate responders (MRs) were 58 (33.1%, 58/175) and 117 (66.9%, 117/175) cases. The medication time for the increase in intraocular pressure in MRs that was 33 (19, 56) days, and in HRs that was 28 (14, 36) days, the difference of which was significant (Z=－1.999, P=0.046). No differences were found in daily doses of ocular hypertension induced by 1% prednisone acetate eye drops between MRs which was 4.24 (3.46, 4.66) drops/day and HRs that was 4.32 (3.84, 5.36) drops/day (Z=－1.676, P=0.094). The genotype and allele frequency distribution of the rs3873352 locus in the case group and HRs group were significantly different from those in the control group (P＜0.05). The intraocular pressure with rs3873352 GG genotype after the medication was higher than that with GC and CC genotype (Z=2.855, 2.628; P=0.013, 0.026), whereas there was no significant difference between different genotypes of rs2523864 (Z=3.580, P＞0.05). Genetic model analysis revealed the risk of SIOH in rs3873352 G allele carriers (GG+GC) was 2.048 times that of non-G allele carriers (OR=2.048, 95%CI: 1.027-4.081, P=0.041). The genotype and allele frequency of rs2523864 locus showed no significant difference between different group (P＞0.05). Conclusions After the use of glucocorticoid eye drops, HRs have an earlier increase in intraocular pressure than MRs. HCG22-rs3873352 gene polymorphism is related to the occurrence of SIOH, GG genotype increases the risk of SIOH, and G allele is a risk gene for SIOH.
【摘要】 目的 了解原发性开角型青光眼患者用2%盐酸卡替洛尔滴眼液后的眼压及眼脉动幅度变化特征。 方法 选取2009年1－12月确诊为原发性开角型青光眼患者19例32只眼。给予2%盐酸卡替洛尔滴眼液点眼1周，2次/d。用动态轮廓眼压计测量患者用药前后的眼压、眼脉动幅度，同时测量患者的血压及心率。比较用药前后眼压及眼脉动幅度的变化，并用SPSS 14.0统计学软件对用药前后的眼压及眼脉动幅度数据进行配对t检验及Pearson相关性分析。 结果 患者用药前后眼压分别为（22.76±4.29）、（17.79±2.93） mm Hg（1 mm Hg=0.133 kPa），眼脉动幅度分别为（3.47±1.00）、（2.63±0.86） mm Hg。患者的眼压及眼脉动幅度用药后较用药前明显降低，差异有统计学意义（Plt;0.01），用药前后的眼压与眼脉动幅度之间存在正相关关系（r=0.444， 0.364；P=0.011， P=0.040）。眼压及眼脉动幅度与患者的血压及心率均无相关性。 结论 原发性开角型青光眼患者用2%盐酸卡替洛尔滴眼液后眼压及眼脉动幅度均有显著降低，眼压与眼脉动幅度有正相关性。眼压及眼脉动幅度与血压及心率无相关关系。【Abstract】 Objective To investigate the variations of intraocular pressure (IOP) and ocular pulse amplitude (OPA) in patients with primary open-angle glaucoma after 2% carteolol hydrochloride was applied. Methods Thirty-two eyes of 19 patients with primary open-angle glaucoma diagnosed between January and December 2009 were chosen to be the study subjects. The patients received 2% cartelol hydrochloride eye drops twice a day for one week. IOP and OPA before and after using cartelol were measured by dynamic contour tonometry (DCT). Blood pressure and heart rate were detected at the same time. The variations of IOP and OPA were analyzed by SPSS 14.0. t test and Pearson correlation analysis were applied. Results The mean IOP and OPA before and after using cartelol were respectively (22.76±4.29) mm Hg (1 mm Hg=0.133 kPa) vs. (17.79±2.93) mm Hg, and (3.47±1.00) mm Hg vs. (2.63±0.86) mm Hg. Both of them decreased significantly after the use of cartelol (P＜0.01). OPA was obviously correlated with IOP both before and after using cartelol (r=0.444, 0.364; P=0.011, 0.040). OPA and IOP had no correlation with blood pressure and heart rate. Conclusions OPA and IOP decreases signifficantly after the use of 2% carteolol hydrochloride. OPA is signifficantly correlated with IOP. OPA and IOP have no correlation with blood pressure and heart rate.