Central corneal thickness in congenital glaucoma

PURPOSE: The aim of this study was to compare central corneal thickness between eyes with congenital glaucoma and normal fellow eyes in unilateral glaucoma or less affected fellow eyes in bilateral glaucoma. METHODS: Eyes of consecutive phakic children with congenital glaucoma and previous glaucoma surgery were examined under chloral hydrate. Complete ophthalmologic examination, central corneal thickness (CCT), axial length, and corneal diameter measurements were performed. Patients were included in the study if presented with intraocular pressure (IOP) less than 21 mm Hg and no biomicroscopic signs of corneal edema. RESULTS: Nine patients were included in the study. The mean CCT in the more affected eye/glaucomatous eye was 522.3 +/- 65.2 microm and in the less affected eye/healthy eye was 579.7 +/- 44.5 microm. This difference was statistically significant (P = 0.0013). CONCLUSION: CCT was significantly thinner in glaucomatous eyes than in normal fellow eyes in phakic children with congenital glaucoma. This finding may be another confounding factor when measuring IOP in these patients.     

Central corneal thickness in children with congenital glaucoma

PURPOSE: To evaluate central corneal thickness in children with congenital glaucoma. MATERIAL AND METHODS: Central corneal thickness was measured with the use of ultrasound pachymeter in 49 eyes of 30 children, with congenital glaucoma aged 0-12 years. RESULTS: Mean central corneal thickness was 462 microm. Very wide differences between minimum and maximum recorded values were observed (380-780 microm). Three groups of patients could be distinguished: with very thin cornea of 380-450 microm (73% children), with normal corneal thickness of about 550 microm (15%) and with very thick cornea of 680-780 microm (12% patients). CONCLUSIONS: 1. Mean central corneal thickness in children with congenital glaucoma is significantly thinner than in healthy children in the same age and in adult patients with glaucoma. A very wide differences between minimum and maximum recorded values, are observed in these patients. 2. The results of applanation tonometric measurements are underestimated in most cases or less frequently overestimated. 3. The measurements of central corneal thickness should be performed in every patient with congenital glaucoma to correct the IOP values.     

Central corneal thickness, tonometry, and ocular dimensions in glaucoma and ocular hypertension.

PURPOSE: To assess possible correlations between central corneal thickness, tonometry, and ocular dimensions. PATIENTS AND METHODS: One hundred seventeen eyes of 117 patients who were not taking any intraocular pressure-lowering medications were studied prospectively. Forty-one patients had ocular hypertension; 13 patients had primary open-angle glaucoma; and 10 patients had normal-pressure glaucoma. Twenty-three healthy eyes were included. Thirty glaucoma suspects (10 patients monitored for possible normal-pressure glaucoma and 20 patients with intermittent ocular hypertension) were included for correlation analysis. Tonometry was performed with Goldmann applanation and pneumotonometry, and central corneal thickness, anterior chamber depth, lens thickness, and axial length were measured ultrasonically. RESULTS: Central corneal thickness was lowest in eyes with normal-pressure glaucoma (538 +/- 51 microm), highest in eyes with ocular hypertension (570 +/- 32 microm), and intermediate and similar in eyes with primary open-angle glaucoma and healthy eyes (547 +/- 34 microm and 554 +/- 32 microm, respectively). These differences were significant (P = 0.028). Goldmann applanation tonometry and central corneal thickness were weakly correlated (r = 0.12, P = 0.205), with a 0.2-mm Hg change per 10-microm variation in central corneal thickness. Pneumotonometry measurements were more strongly correlated with central corneal thickness (r = 0.21, P < 0.05). Lens thickness was strongly correlated with age (r = 0.57, P < 0.001). Anterior chamber depth was negatively correlated with lens thickness and age (r = -0.29, P < 0.005 and r = -0.25, P < 0.01). Axial length was correlated with anterior chamber depth and age (r = 0.5, P < .001 and r = -0.19, P < 0.05). CONCLUSION: Eyes diagnosed as having ocular hypertension have thicker corneas and eyes labeled as having normal-pressure glaucoma have thinner corneas, when compared with healthy eyes or eyes with primary open-angle glaucoma. The effect of central corneal thickness on Goldmann applanation tonometry accuracy appears to be small and usually not clinically relevant. When corneal thickness is markedly different from normal, the clinician may need to factor this into diagnosis and management.     

Eye growth in children with primary congenital glaucoma after trabeculectomy

PURPOSE: Evaluation of the influence of intraocular pressure (IOP) after trabeculectomy on the axial length and refraction of eyeballs in children with primary congenital glaucoma. MATERIAL AND METHODS: Thirty six eyes of 23 children at the age from 7 days to 6.5 years (mean 17.1 months), were examined. Measurements of corneal diameter, axial length, IOP and refraction were done before trabeculectomy and in the long-term follow-up (mean 7.9 years) after surgery. RESULTS: Horizontal corneal diameter didn't change and ranged from 10 to 15 mm, mean 13.22 mm. Mean value of axial length before trabeculectomy was 22.45 mm and 23.27 mm at last visit. The difference was statistically significant. The axis decreased in 3 eyes, was the same in 3 eyes. In the others the eye growth changed proportionally to the age of child. IOP values were statistically lower after surgery (mean 16 mmHg) than before treatment (mean 35.51 mmHg). There was no correlation between IOP and axial length of eyeballs (p = 0.69) and between IOP and refraction changes (p = 0.42) in the long-term follow-up. CONCLUSIONS: There is small influence of normalised IOP after trabeculectomy on size of eyeballs and refraction in children with primary congenital glaucoma. The development of eyeballs even buphthalmic is proportionally to the age.     

Central corneal thickness and corneal diameter in patients with childhood glaucoma

PURPOSE: To determine and compare the central corneal thickness (CCT) and corneal diameter among groups of patients with childhood glaucomas and assess the relationship between CCT and corneal diameter in these patients. DESIGN: A multicenter observational case series using prospective and retrospective data. METHODS: Patients from the Scheie Eye Institute, Children's Hospital of Philadelphia, and Emory and Vanderbilt Medical Centers with childhood glaucomas were eligible to participate. Retrospective data on CCT and corneal diameter of these patients were collected when available; otherwise, patients were asked to return to the ophthalmology clinics for measurements. Patients with corneal edema or central corneal scarring were excluded. One hundred eighty four glaucomatous eyes from 109 patients (median age = 9.0 y; age range = 0 to 60 y) were included. RESULTS: The mean CCT (+/-SE) was 651.1+/-63.5 microm for aphakic, 528.7+/-38.5 microm for Axenfeld-Rieger, and 563.4+/-67.9 microm for 1 degrees infantile eyes. The mean corneal diameter in aphakic, Axenfeld-Rieger, and 1 degrees infantile glaucoma eyes were 11.2+/-1.0, 12.5+/-0.9, and 13.2+/-1.2 mm, respectively. There was a significant difference in CCT and in corneal diameter between aphakic and 1 degrees infantile glaucoma eyes, and between aphakic and Axenfeld-Rieger eyes (P < 0.0001). There was a negative correlation between CCT and corneal diameter in all eyes (r = -0.41, P < 0.0001). CONCLUSIONS: Patients with aphakic glaucoma are different from those with congenital glaucoma or Axenfeld-Rieger in CCT and corneal diameter. A patient with pediatric glaucoma and a larger corneal diameter was more likely to have a thinner CCT. Attention should be paid to the CCT of patients with childhood glaucomas for interpretation of intraocular pressure.     

Central corneal thickness correlated with glaucoma damage and rate of progression

PURPOSE: To evaluate whether the amount of glaucomatous optic nerve damage at presentation of the patient and the rate of progression of glaucoma during follow-up are related to central corneal thickness. METHODS: The prospective observational clinical study included 861 eyes of 454 white subjects (239 normal eyes of 121 subjects, 250 ocular hypertensive eyes of 118 patients, 372 eyes of 215 patients with chronic open-angle glaucoma). For 567 eyes (304 patients) with ocular hypertension or chronic open-angle glaucoma, follow-up examinations were performed, with a mean follow-up time of 62.7 +/- 33.2 months (median, 60.8; range, 6.2-124.9). All patients underwent qualitative and morphometric evaluation of color stereo optic disc photographs and white-on-white visual field examination. Central corneal thickness was measured by corneal pachymetry. RESULTS: Central corneal thickness correlated significantly (P < 0.001) and positively with the area of the neuroretinal rim and negatively with the loss of visual field. Development or progression of glaucomatous visual field defects detected in 119 (21.0%) eyes was statistically independent of central corneal thickness, in univariate (P = 0.99) and multivariate Cox regression analyses (P = 0.19). CONCLUSIONS: At the time of patient referral, the amount of glaucomatous optic nerve damage correlated significantly with a thin central cornea. Progression of glaucomatous optic nerve neuropathy was independent of central corneal thickness, suggesting that central corneal thickness may not play a major role in the pathogenesis of progressive glaucomatous optic nerve damage.     

Corneal diameter and axial length in congenital glaucoma

The corneal diameter was recorded and the ocular axial length measured by A-scan ultrasonography in 31 eyes of 17 children (ages 0.05 to 7.0 years) who had undergone or were about to undergo surgery for primary congenital glaucoma. These measurements were also done in 60 normal eyes of 33 children (ages 0.20 to 9.6 years) undergoing nonophthalmic surgery. Both measures were usually greater than normal in the glaucomatous eyes. However, the corneal diameter was more sensitive than the axial length in identifying congenital glaucoma. The axial length measurement did not provide additional useful information for any of the eyes. We conclude that the corneal diameter is a more reliable guide than the axial length in the assessment of congenital glaucoma. A transparent plastic gauge for rapid and accurate measurement of the corneal diameter is described.     

Corneal thickness and axial length

PURPOSE: A thin central cornea has been reported to be a risk factor for developing primary open-angle glaucoma among ocular hypertensive eyes. A thin scleral bed of lamina cribrosa seen in deeply excavated optic nerves in glaucomatous eyes is a quintessential finding in advanced glaucomatous eyes. Association between thin cornea and weak sclera contributing to vulnerability of lamina cribrosa has been postulated. The purpose of this study is to determine whether there is an association between corneal thickness and axial length of human eyes in a clinical setting. DESIGN: This is an observational, retrospective cross-sectional study. METHODS: The ocular parameters of 1,084 consecutive eyes with both corneal thickness and axial length measurements were analyzed and compared by age, gender, and race. RESULTS: In the total patient study group, there was no statistically significant association between central corneal thickness and axial length. Subgroup analysis by age, gender, and race also failed to show an association. CONCLUSIONS: Central corneal thickness and axial length are independent occurrences. Thin corneas are not associated with longer eyes.     

Retinal microcirculation correlates with ocular wall thickness, axial eye length, and refraction in glaucoma patients.

PURPOSE: To examine the correlations of refraction, axial eye length, and posterior eye wall thickness with retinal microcirculation. PATIENTS AND METHODS: In a prospective study, 25 patients with primary open-angle glaucoma, 12 patients with ocular hypertension, and 12 healthy subjects were examined; only one eye of each participant was considered in the analysis. Posterior eye wall thickness and axial eye length were measured with standardized A-scan ultrasonography. Retinal microcirculation temporal to the optic disc was determined by a scanning laser Doppler flowmeter using automatic full-field perfusion image analyzer software. RESULTS: In glaucoma patients, temporal retinal mean flow exhibited significant correlation to the eye wall thickness (r = 0.470, P = 0.042), axial eye length (r = -0.570, P = 0.011), and refraction of the eye (r = 0.520, P = 0.022). In glaucomatous eyes, the temporal retinal mean flow was significantly lower than in healthy subjects or in ocular hypertensive patients (P = 0.01). CONCLUSIONS: Myopic eyes have longer axial eye length and thinner ocular wall than emmetropic eyes. In glaucoma patients, the longer the axial eye length and the thinner the ocular wall, the more reduced the retinal microcirculation. The reduced microcirculation found in myopic glaucomatous eyes might contribute to the development of glaucomatous damage in these eyes.     

Optic disc area in different types of glaucoma

AIM: To evaluate the possible relationship of optic disc area with retina nerve fiber layer in different glaucoma subtypes. METHODS: One eye each was chosen from 45 patients with ocular hypertension, 45 patients with primary open angle glaucoma, 45 patients with pseudoexfoliation glaucoma and 45 healthy controls followed in our hospital. The records of the patients were reviewed retrospectively. Optic disc area and circumpapillary retina nerve fiber layer measurements were obtained using optical coherence tomography. Central corneal thickness was measured by ultrasound pachymetry. RESULTS: The median disc area in the patients with primary open angle glaucoma was significantly higher than the patients with ocular hypertension (2.19 vs 1.90 mm2, P=0.030). The median retina nerve fiber layer was thinner in the patients with primary open angle glaucoma and pseudoexfoliation glaucoma than the patients with ocular hypertension for superior, inferior and temporal quadrants. After adjustment for age, no difference in central corneal thickness was found between the groups. Greater disc area was associated with thicker retinal nerve fiber layer for superior, inferior and nasal quadrants in the patients with primary open angle glaucoma. There was no correlation between disc area and central corneal thickness measurements of the groups. CONCLUSION: Disc size affects the retinal nerve fiber layer thickness in eyes with primary open angle glaucoma and is a possible risk factor for glaucomatous optic nerve damage.     

Association between corneal hysteresis and central corneal thickness in glaucomatous and non‐glaucomatous eyes

Purpose: We aimed to determine corneal hysteresis values (CH) using the ocular response analyser (ORA) in non‐glaucomatous and glaucomatous eyes and their relationship with central corneal thickness (CCT). Methods: Corneal hysteresis, intraocular pressure (IOP) as measured by Goldmann applanation tonometry (GAT) and CCT were prospectively evaluated in 74 non‐glaucoma subjects with IOP < 21 mmHg and in 108 patients with treated primary open‐angle glaucoma (POAG). One eye in each subject was randomly selected for inclusion in the analysis. Results: Mean (± standard deviation [SD]) age was 59.2 ± 14.2 years in the non‐glaucoma group and 62.4 ± 9.8 years in the glaucoma group. Mean (± SD) GAT IOP was 15.7 ± 2.65 mmHg and 16.38 ± 2.73 mmHg in the non‐glaucoma and glaucoma groups, respectively. There was no statistically significant difference between the two groups in mean age (p = 0.396) or mean GAT IOP (p = 0.098). Mean (± SD) CH was 10.97 ± 1.59 mmHg in the non‐glaucoma and 8.95 ± 1.27 mmHg in the glaucoma groups, respectively. The difference in mean CH between the two groups was statistically significant (p < 0.0001). There was a strong positive correlation between CH and CCT in the non‐glaucoma group (r = 0.743) and a significantly (p = 0.001) weaker correlation (r = 0.426) in the glaucoma group. Conclusions: Corneal hysteresis was significantly lower in eyes with treated POAG than in non‐glaucomatous eyes. The corneal biomechanical response was strongly associated with CCT in non‐glaucoma subjects, but only moderately so in glaucoma patients. It can be assumed that diverse structural factors, in addition to thickness, determine the differences in the corneal biomechanical profile between non‐glaucomatous and glaucomatous eyes. Corneal hysteresis could be a useful tool in the diagnosis of glaucoma.     

青光眼患者角膜中央厚度与眼压关系的Meta分析

目的：系统回顾正常人群和青光眼患者中央角膜厚度与眼压的研究资料,探讨两者之间的关联与机制。
　　方法：在MEDLINE数据库和Science Direct数据库搜索有关角膜中央厚度与眼压关系的研究资料。另外在南方医科大学外文科部搜索2004/2006“眼科年刊”期刊。搜索
　　关键词包括：角膜中央厚度、眼压、青光眼、高眼压症、剥脱青光眼、压平眼压计、厚度测量法、原发性开角青光眼、Goldmann压平眼压计。应用以下排除标准：1)非英语文献研究;2)在2005年以前的研究;3)案例性研究和案例点评性研究;4)与治疗方案或外科手术技术有关的研究;5)将青光眼与其他疾病,如糖尿病、高血压、心血管疾病来比,作为辅助变量;6)儿童作为研究对象的研究;7)动物作为研究对象的研究。
　　结果：搜索产生了13项研究,包括12个观察性研究和1个病例对照研究。与对照组相比,青光眼患者眼压水平明显升高( SMD：0.50,95% CI：0.30~0.70, Z=4.88, P<0.001);青光眼组患者角膜中央厚度水平有明显降低(SMD：-0.14,95% CI：-0.23~-0.05, Z=3.14, P=0.002)。 Meta-回归分析结果显示年龄跟两个组之间观察到的 CCT 差异有统计学意义( P=0.025)。
　　结论：与正常眼组相比,青光眼组患者表现为角膜中央厚度变薄和眼压增高。     

The glaucoma suspect: Differentiation of the future glaucomatous eye from the non-glaucomatous suspect eye

We examined the eyes of a group of patients entered into and still continuing in a glaucoma suspect study. Over time, some remained unchanged while others developed chronic open-angle glaucoma (COAG). By comparing the data obtained by ultrasonic measurement of the axial length (A) and central corneal thickness (CCT), along with measurement of intra-ocular pressure (IOP) from these patients and normal control subjects, we found no differences. However, by combining these factors in a calculation of eye-wall stress we found a significant difference between the glaucoma suspect and the future glaucomatous eye.     

Central corneal thickness in low-tension glaucoma

BACKGROUND: It is possible that the intraocular pressure (IOP) is underestimated in eyes whose central cornea is thinner than normal. The objective of this study was to determine and establish the significance of central corneal thickness in patients with low-tension (normal-tension) glaucoma compared with those with chronic open-angle glaucoma (COAG) or ocular hypertension and healthy eyes. METHODS: The study was carried out from February 1998 to May 1999. Central corneal thickness was measured by ultrasonic pachymetry and IOP was measured by Goldmann applanation tonometry in 25 patients with low-tension glaucoma (untreated IOP less than 21 mm Hg with evidence of optic nerve head damage and corresponding visual field loss on automated perimetry), 80 patients with COAG (untreated IOP 21 mm Hg or greater with evidence of optic nerve head damage and corresponding visual field loss on automated perimetry), 16 patients with ocular hypertension (untreated IOP 21 mm Hg or greater, with normal optic nerve head and no history of glaucoma or elevated IOP, and normal visual field on automated perimetry) and 50 control subjects (untreated IOP less than 21 mm Hg with normal optic nerve head and no history of glaucoma or elevated IOP). Analysis with Pearson's product-moment correlation was performed to determine the correlation of IOP and central corneal thickness, and one-way analysis of variance was used to compare corneal thickness between groups. RESULTS: The central cornea was significantly thinner in the low-tension glaucoma group (mean 513.2 mu [standard deviation (SD) 26.1 mu]) than in the COAG group (mean 548.2 mu [SD 35.0 mu]) and the control group (mean 556.7 mu [SD 35.9 mu]) (p < 0.001). No significant difference in corneal thickness was found between the COAG and control groups. The ocular hypertension group had significantly thicker corneas (mean 597.5 mu [SD 23.6 mu]) than the three other groups (p < 0.001). INTERPRETATION: Patients with low-tension glaucoma may have thinner corneas than patients with COAG and healthy subjects. This results in underestimation of their IOP. Corneal thickness should be taken into account when managing these patients to avoid undertreatment.     

Inter-instrument agreement and influence of central corneal thickness on measurements with Goldmann, pneumotonometer and noncontact tonometer in glaucomatous eyes

PURPOSE: This study was conducted to compare the intraocular pressure (IOP) measurements by the Goldman applanation tonometer (GAT), non contact tonometer (NCT) and the ocular blood flow (OBF) pneumotonometer in different IOP ranges in glaucomatous eyes. The effect of central corneal thickness (CCT) on IOP measurement in chronic glaucomatous eyes using the three different tonometers was also evaluated. MATERIALS AND METHODS: IOP measurements of 130 eyes of primary glaucoma patients were performed using GAT by an ophthalmologist while NCT and OBF-pneumotonometer measurements were performed by an experienced optometrist. The IOP values were compared amongst the three instruments in the three different IOP ranges (0-18 mmHg, > 18 to 25 mmHg, > 25 mmHg). CCT was also measured in all patients. RESULTS: The mean of paired difference between GAT and NCT was 0.9 +/- 3.1 mmHg while that between GAT and OBF-pneumotonometer was 0.3 +/- 3.4 mmHg. The OBF-pneumotonometer and NCT were more affected by corneal thickness (0.41 mmHg and 0.4 mmHg / 10 micro corneal thickness respectively) while GAT was the least affected by corneal thickness (0.3 mmHg / 10 micro corneal thickness) though the difference was not statistically significant ( P =0.42). CONCLUSION: With appropriate correction for corneal thickness the NCT and OBF-pneumotonometer can be used as reliably as GAT in following up glaucomatous patients.     

近视患者中央角膜厚度及其相关因素分析

目的:探讨与近视患者中央角膜厚度相关的因素。方法:近视及近视散光患者2217例(4398眼),用超声角膜测厚仪测量角膜中央厚度,电脑验光仪测量屈光度,非接触眼压计测量眼压,OrbscanⅡ眼前节分析仪查角膜地形图测量角膜曲率,并统计患者性别、年龄及配戴软性角膜接触镜情况。结果:近视患者平均中央角膜厚度为548.57±30.42μm,男女眼之间、左右眼之间、低龄与高龄眼之间平均中央角膜厚度均无统计学差异。中央角膜厚度与屈光度呈正相关(r=0.506,P=0.000)。中央角膜厚度与眼内压呈正相关(r=0.634,P=0.000)。中央角膜厚度与角膜曲率之间无相关性。中央角膜厚度与是否配戴软性角膜接触镜有关,长期持续配戴软性角膜接触镜患者与无角膜接触镜配戴史患者平均中央角膜厚度的差异有显著性(P=0.000)。结论:近视患者中央角膜厚度与屈光度、眼内压及配戴软性角膜接触镜情况等因素有相关性。     

Success of trabeculotomy in patients with congenital glaucoma operated on within 3 months of birth

AIMS: To determine the efficacy and safety of trabeculotomy in congenital glaucoma patients operated on within first 3 months of birth. METHODS: A total of 36 eyes of 24 patients with congenital glaucoma, who underwent primary trabeculotomy within first 3 months of birth were included. Preoperative and postoperative intraocular pressures (IOP), corneal clarity, diameter, axial length, success rates, and complications were evaluated in this study. RESULTS: The mean follow-up was 38.38+/-11.77 months (range 12-48 months). Mean IOP was 33.16+/-7.28 mmHg (range 23-50 mmHg) preoperatively. At the final follow-up visit, the mean IOP was 21.41+/-7.34 mmHg (range 8-38 mmHg). Pre-and postoperative IOP differences were statistically significant at all examination periods (P<0.001). A12-, 24-, and 36-month success rates were 92, 82, and 74%, respectively. Survival analysis regarding to gender, preoperative corneal diameter and consaguinity were not statistically significant. Only preoperative axial length was a statistically significant parameter (P=0.024) for success. Postoperatively normal corneal clarity was achieved in 29 eyes (80.5%). The main complications were shallow anterior chamber in one (4.2%) eye and detachment of Descement's membrane in two (8.4%) eyes. CONCLUSIONS: Primary trabeculotomy is a safe and effective procedure for congenital glaucoma patients when operated within 3 months of birth. It has a favourable IOP control and a low rate of complications in three year period.     

中央角膜厚度对非接触式眼压计测量值的影响

目的 探讨中央角膜厚度（central corleal thickness,CCT）对非接触式眼压计测量值的影响及CCT与某些眼部参数的关系.方法 应用超声测厚仪测量正常人（26例）、高眼压症（28例）、慢性闭角型青光眼（13例）和原发性开角型青光眼（24例）患者的CCT,同时测量以上入选者的眼内压（intraocular pressure,IOP）、眼轴长度、角膜曲率及屈光度,观察CCT与各参数之间的关系.结果 正常组的眼内压与CCT存在正相关关系（Pearson r=0.499,P=0.009）,CCT与眼轴长度（Pearson r=0.157,P=0.137）、屈光度（球镜）（Pearson r=-0.114,P=0.282）及角膜曲率（水平径 Pearson r=-0.167,P=0.114 垂直径 Pearson r=-0.034,P=0.746）不相关.结论 CCT与眼轴长度、屈光度（球镜）及角膜曲率不相关,在正常对照组与眼内压呈正相关.     

Clinical comparison of pascal dynamic contour tonometry and goldmann applanation tonometry in asymmetric open-angle glaucoma

PURPOSE: To investigate and compare the relationships between glaucomatous visual field loss and intraocular pressure (IOP) as measured by both Pascal dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT). PATIENTS AND METHODS: All primary open-angle glaucoma and normal tension glaucoma patients seen between July 2005 and June 2006 with at least 2 sets of good-quality, bilateral DCT and GAT measurements were retrospectively identified. Additional inclusion criteria required that all subjects had repeatable, asymmetric glaucomatous visual field loss that corresponded with asymmetric glaucomatous optic neuropathy. After mean IOP values were computed and visual fields were scored using Advanced Glaucoma Intervention Study (AGIS) criteria, paired-eye comparisons were conducted using right versus left eyes and higher versus lower AGIS-score eyes. RESULTS: Sixty-seven (42 primary open-angle glaucoma, 25 normal tension glaucoma) subjects met all criteria for study inclusion. Per paired t test, mean DCT-IOP was significantly higher in the higher AGIS-score eyes compared with the lower AGIS-score eyes (16.3 vs. 15.5 mm Hg, P=0.004), whereas GAT-IOP was not significantly different in these same eyes (14.5 vs. 14.4 mm Hg, P=0.56). Mean IOP difference between the 2 methods was significantly larger in higher versus lower AGIS-score eyes (P<0.001), and 72% of the subjects demonstrated larger intermethod IOP differences in their higher AGIS-score eye compared with their lower AGIS-score eye (P<0.001; 95% confidence interval: 0.59-0.82). Multivariate linear regression analysis revealed that AGIS-score differences between eyes were independently associated with both intermethod IOP differences between eyes (P=0.004) and central corneal thickness (CCT) differences between eyes (P=0.04). CCT, however, was not associated with intermethod IOP differences within or between eyes. CONCLUSIONS: These findings suggest that DCT-IOP is correlated with glaucomatous damage, and moreover, DCT-IOP is more closely related to extent of glaucoma damage than is GAT-IOP. The most likely explanation for these results is that GAT-IOP systematically underestimates IOP compared with DCT-IOP. Our findings also support the hypothesis that corneal biomechanical factors other than CCT are major confounders of applanation tonometry measurements.     

角膜厚度和眼轴与眼压相关性的分析

目的回顾性研究中央角膜厚度（CCT）、眼轴长度对眼压的影响。方法 155例310只眼行LASIK手术前检查,角膜厚度和眼轴长度由A超测量获得,眼压由Cannon非接触式眼压计测量,进行Pearson相关分析和偏相关分析。结果非接触式眼压IOP数值明显依赖于CCT（r=0.405,=0.000）,IOP与眼轴长度之间具有统计学意义的相关性（r=0.137,〈0.01）。结论 CCT对Cannon非接触式眼压计测量的眼压值有明显影响,眼轴长度与IOP之间有相关性。