Comparison of central corneal thickness in patients participating in a glaucoma screening programme and those who were examined in the glaucoma unit

BACKGROUND: The aim of this study was to compare central corneal thickness (CCT) and intraocular pressure in patients participating in a glaucoma screening programme and patients who were examined in the glaucoma unit. MATERIALS AND METHODS: 406 patients of a glaucoma screening programme (Salzburg-Moorfields collaborative glaucoma study) were included in this study. In addition a group of 406 patients who were admitted to the glaucoma clinic for a detailed glaucoma examination was included (outpatient clinic group). In all participants central corneal thickness (CCT) was measured and possible relations of CCT within the study groups were statistically analysed. RESULTS: In the population screening group the mean central corneal thickness in normal subjects was 536+/-4.3 microm, in patients with ocular hypertension (OHT) 552+/-5.7 microm, patients suffering from a normal tension glaucoma (NTG) showed a mean CCT of 534+/-14.2 microm and those with primary open angle glaucoma (POAG) had a value of 521+/-17.9 microm. In the 'outpatient clinic group' the OHT subgroup had a mean CCT of 553+/-6.8 microm, the NTG subgroup of 529+/-26.5 microm and the one with POAG had a mean of 527+/-19.8 microm. In addition, CCT was measured in all glaucoma patients whose "partner" eye was healthy (544+/-5 microm) and included in this study as part of the normal subgroup. In both groups (screening group and outpatient group), CCT was significantly higher in OHT patients than in normals. In contrast, no statistically significant difference between normals and NTG or POAG patients was detected. Intraocular pressure was significantly lower in the screening groups than in the other ones. CONCLUSIONS: Our data confirm the previously published results concerning OHT and healthy subjects. In this study no significant difference between NTG or POAG subjects and normal eyes was detected. The lower IOP in the screening population can be explained by the fact that patients contacting the screening program are self selected whereas patients of the glaucoma unit are admitted by practising ophthalmologists and are, therefore, rather advanced cases or carrying special risk factors.     

Central corneal thickness of normal tension glaucoma patients in Japan

PURPOSE: To compare central corneal thickness (CCT) of patients with normal tension glaucoma (NTG) with that of age-matched normal subjects, patients with open-angle glaucoma (POAG) and ocular hypertension (OH) subjects in Japan. METHODS: Central corneal thickness was measured in 79 NTG, 61 POAG, 73 OH, and 50 normal subjects with an ultrasonic pachymeter. One eye for 1 subject randomly selected in each group was used for inter-group comparison. The relationship between CCT and the maximum intraocular pressure (IOP) measured by Goldmann applanation tonometer with no ocular hypotensive medication (NTG, OH, and normal subjects) or under medication (POAG patients) was analyzed. RESULTS: The CCT of OH subjects (582 +/- 32 microm; mean +/- SD) was significantly greater than that of the other groups (P <.001), while no difference was seen in CCT among normal (552 +/- 36 microm), NTG (548 +/- 33 microm) and POAG (550 +/- 33 microm) subjects. In normal subjects, CCT and the maximum IOP were significantly correlated but the correlation coefficient was small (r = 0.420, P <.05). CONCLUSIONS: Central corneal thickness shows no significant difference among NTG, POAG, and normal subjects in Japan, while it is significantly greater in OH subjects. The CCT has little influence on the diagnosis of NTG in Japan.     

角膜厚度与高眼压症及青光眼的眼压

目的 探讨高眼压症、正常眼压性青光眼、原发性开角型青光眼患者及正常人的角膜厚度差异,分析角膜厚度与眼压间的关系,以及角膜厚度的测定对各型青光眼的诊断意见。方法 用超声波角膜测厚仪检测７３例（７３只眼）高眼压症、７９例（７９只眼）正常人的中央角膜厚度,并将其测定结果进行比较。回顾性分析每只青光眼治疗前的最高眼压（Ｇｏｌｄｍａｎｎ）,包括２４ｈ眼压曲线,用Ｅｈｌｅｒ法通过中央角膜厚度对眼压进行校正。结     

Central corneal thickness and vascular risk factors in normal tension glaucoma

BACKGROUND: Normal tension glaucoma (NTG) has been shown to be associated with reduced central corneal thickness (CCT). The association of NTG with vascular risk factors is well documented. It has been postulated that a subset of NTG patients are misclassified due to incorrect intraocular pressure measurements on thin corneas. The aim of this study was to establish whether corneal thickness in NTG differs between patients with vascular risk factors specific to NTG and those without. METHODS: The study comprised a retrospective analysis of 108 eyes of 54 patients with NTG and 54 patients with primary open-angle glaucoma (POAG). Corneal thickness was measured in all patients. Vascular risk factors were recorded. Patients with NTG were divided into two groups depending on the presence (group A) or absence (group B) of vascular risk factors. RESULTS: The mean CCT was 549 +/- 34 microm in patients with POAG and 528 +/- 31 microm in patients with NTG (p = 0.001). Mean CCT was 512 +/- 31 microm in group A (n = 13) and 533 +/- 31 microm in group B (n = 41) (p = 0.034). A total of 40.9% of those with thin corneas (n = 22) had vascular risk factors versus only 12.5% of those with CCT within the normal range (n = 32) (p < 0.05). CONCLUSION: Central corneal thickness in NTG was significantly lower than in POAG and corneas were thinner in NTG patients with vascular risk factors than in those without. Vascular risk factors were significantly more common in patients with thin corneas. The finding of reduced corneal thickness in NTG does not obviate the need to consider vascular risk factors in the pathophysiology of the disease.     

相干光断层扫描仪检测正常人及青光眼患者中央角膜厚度

目的探讨相干光断层扫描仪(OCT)测量正常人、原发性开角型青光眼(POAG)、正常眼压性青光眼(NTG)、高眼压症(OHT)患者的中央角膜厚度(CCT)。方法采用OCT3测量正常人143例(143只眼)、POAG患者36例(36只眼)、NTG患者39例(39只眼)及OHT患者40例(40只眼)的CCT,并进行单因素4水平设计定量资料的方差分析;用线性回归方法分析正常人CCT与Goldmann压平眼压测量值的相关关系;对OCT测量CCT观察者间和观察者内的一致性进行类内相关系数(ICC)分析。结果正常组、POAG组、NTG组及OHT组的平均CCT值分别为(523.66±32.13)μm、(530.92±27.32)μm、(506.92±21.49)μm及(573.13±27.39)μm。POAG组与正常人组的平均CCT值差异无统计学意义(P=0.099);OHT组的平均CCT值大于其他各组,均P<0.01;NTG组的平均CCT值小于其他各组,均P<0.01。正常组CCT与眼压值呈正相关(r=0.318,R2=0.101,P<0.01)。OCT测量CCT的测量者间和测量者内的ICC值分别为0.995和0.996。结论OCT可以准确地测量CCT;NTG患者平均CCT比正常人薄,而OHT患者比正常人厚;CCT可以影响Goldmann压平眼压计的测量值,但贡献率较小。(中华眼科杂志,2006,42:199-203)     

Evaluation analysis of blood flow of peripapillary area in glaucoma patients using scanning laser Doppler flowmetry

PURPOSE: To evaluate capillary blood flow and velocity in retinal peripapillary area in primary open angle glaucoma (POAG), normal tension glaucoma (NTG), pseudoexfoliation glaucoma (PEXG) and age matched control group (C) using scanning laser Doppler flowmetry (Heildelberg Retina Flowmeter). MATERIAL AND METHOD: One randomly selected eye of 17 POAG patients (mean age 59.3 +/- 2.6), 18 NTG patients (mean age 56.4 +/- 2.4), 17 PEXG patients (63.3 +/- 2.8) and 15 healthy subjects (mean age 55.8 +/- 3.8) underwent examination with scanning laser Doppler flowmetry. The measurements were performed at the superior and inferior temporal peripapillary retinal area. The measured parameters were capillary blood flow and velocity of the moving erythrocytes. Each image was analysed using the program AFFPIA. This software calculates the hemodynamic parameter flow of each pixel. Comparison of value obtained from patients and control participants were made using Student's t test. RESULTS: Scanning laser Doppler flowmetry results showed a significant reduction in blood flow at the superior and inferior temporal peripapillary area in POAG and NTG patients compared to control group (p < 0.04). The POAG and NTG patients had also significantly decreased velocity at the inferior temporal peripapillary retinal area compared to control group. No statistical difference was found between blood flow and velocity in POAG compared with NTG. When compared with the control participants, patients with PEXG showed significant decreases in the mean blood flow at the inferior temporal quadrant (p < 0.05), while the differences in the mean flow and velocity at the superior quadrant between those groups were not statistically significant. CONCLUSIONS: Our findings indicate a reduction in ocular blood flow at the temporal peripapillary retinal area in patients with POAG and NTG compared to age matched control participants. The peripapillary retinal microcirculation is not significantly altered in patients with PEXG compare with POAG and JNC. The blood flow parameters in the capillaries are lower in JNC retinas, the difference however is not significant. Further clinical investigation is required having groups homogeneous with respect to stage of glaucoma and controlled for factors known to effect perfusion pressure.     

Central corneal thickness in primary open angle glaucoma, pseudoexfoliative glaucoma, ocular hypertension, and normal population

PURPOSE: This study was designed to determine the relationship between central corneal thickness (CCT) and intraocular pressure (IOP) measured by applanation tonometer in glaucomatous, ocular hypertensive, and normal eyes. METHODS: A total of 125 subjects were included in the study. Twenty-six had primary open angle glaucoma (POAG), 25 had pseudoexfoliative glaucoma (PXG), 24 had ocular hypertension (OHT), and 50 of them were normal. IOP values were measured by Goldmann applanation tonometer whereas CCT values were measured by ultrasonic pachymeter. RESULTS: CCT values in the OHT group (595.75+/-22.52 microm) were greater than the CCT values of the POAG group (539.92+/-21.50 microm), the PXG group (526.28+/-31.73 microm), and the normal group (533.96+/-29.25 microm) (p<0.05). Eight patients who were diagnosed with OHT showed IOP values of 21 mm Hg or lower with corrected IOP values according to CCT. CONCLUSIONS: Increased CCT may lead to falsely high values of IOP measured with Goldmann applanation tonometer. In this study, when IOP values of the OHT group were redefined according to the formulae regarding the CCT, the authors noted that one third of them were normal. Determination of the CCT in OHT cases is crucial since it has great impact on IOP values, measured with applanation tonometer, which is the main parameter in the diagnosis and follow-up of glaucoma.     

Corneal biomechanical properties in primary open angle glaucoma and normal tension glaucoma

PURPOSE: To determine and compare the corneal biomechanical properties between eyes with primary open angle glaucoma (POAG) and eyes with normal tension glaucoma (NTG). PATIENTS AND METHODS: Prospective cross-sectional study. Consecutive eligible POAG and NTG patients attending the Glaucoma Clinic had assessment of their corneal biomechanical properties-corneal hysteresis (CH) and corneal resistance factor (CRF)-using the Ocular Response Analyzer by an observer masked to the diagnosis. Exclusion criteria included previous intraocular surgery, corneal pathology, inflammatory connective tissue disease, and refraction of 5-dimensional or over. If both eyes were eligible, then the right eye was used for analysis. The main outcome measures were corneal hysteresis and CRF measurements. Data analysis was performed using the t test and general linear model. RESULTS: Eighty-one patients (80 whites) were analyzed. Forty had NTG, whereas 41 had POAG. Thirty-five were females. There was a statistically significant difference in mean CH (NTG 9.6+/-1.3 mm Hg; POAG 9.0+/-1.4 mm Hg; P=0.01), but not in mean CRF (NTG 9.9+/-1.4; POAG 10.8+/-1.7; P=0.06). The highest recorded Goldmann applanation intraocular pressure (IOP) was statistically significantly associated with lower CH (P=0.01) and higher CRF (P=0.02). CONCLUSIONS: There was a small but statistically significant difference in the mean CH between POAG and NTG (CH was higher in NTG). The highest recorded Goldmann applanation IOP was also statistically significantly correlated with lower CH and higher CRF, suggesting that alterations to the corneal biomechanical properties may occur as a result of chronic raised IOP in POAG.     

Assessment of the retinal blood flow by DRG retina Doppler in primary open angle glaucoma and normal tension glaucoma

PURPOSE: The aim of the study was to evaluate the blood flow in central retinal artery (CRA) in primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). MATERIAL AND METHODS: Two groups of patients were examined: I group consisted of 15 patients (19 eyes) with POAG, II group of 16 patients (32 eyes) with NTG. The controls were age-matched healthy persons. Blood flow velocities and resistance index in central retinal artery were measured by DRG Retina-Doppler. RESULTS: We found decreased blood flow velocity in CRA in most of the patients with NTG and in part of the patients with POAG. Significant increase of resistance index was found only in NTG group. CONCLUSION: Our study confirmed that assessment of the blood flow in central retinal artery appears to be a valuable method in diagnosis of neuropathy mechanism in glaucoma.     

动态轮廓眼压计在正常眼压性青光眼及原发性开角型青光眼的应用研究

目的:应用动态轮廓眼压计(dynamic contour tonometer,DCT)测量正常眼压性青光眼(normal tension glaucoma,NTG)及原发性开角型青光眼(primary open angle glaucoma,POAG)患者的眼压(intraocular pressure,IOP)及眼脉动幅度值(ocular pulse amplitude,OPA),并探讨影响OPA测量值的相关因素。方法:选取NTG患者20例,POAG患者21例及正常对照组各20例,应用Goldmann压平眼压(Goldmann applanation tonometer,GAT)及DCT测量IOP,同时测量了中央角膜厚度(central corneal thickness,CCT)、眼轴(axial length,AL)、心率(heart rate,HR)、收缩压(systolic blood pressure,SBP)、舒张压(diastolic blood pressure,DBP)等指标,并探讨GAT,DCT两种眼压计测量的相关性,进而分析OPA测量值的影响因素。结果:三组被检者的IOP,OPA,SBP及DBP差异均有统计学意义(P<0.05),而CCT,AL及HR差异无统计学意义(P>0.05)。其中OPA值NTG组为(1.7±0.9)mmHg,POAG组为(2.8±0.7)mmHg,正常对照组为(2.4±0.6)mmHg;NTG组与POAG组比较(P=0.001),与正常对照组比较(P=0.005)差异均有统计学意义,POAG组与正常对照组比较(P=0.502)差异无统计学意义;OPA值与IOP,HR及CCT无相关性(P>0.05),与AL,SBP及DBP具有一定的相关性(P<0.05)。结论:NTG患者与POAG患者及正常人的OPA值存在差异,同时OPA值受AL及SBP及DBP影响。     

Comparisons of ganglion cell-inner plexiform layer loss patterns and its diagnostic performance between normal tension glaucoma and primary open angle glaucoma: a detailed, severity-based study

AIM: To evaluate the patterns of macular ganglion cell-inner plexiform layer (GCIPL) loss in normal tension glaucoma (NTG) and primary open angle glaucoma (POAG) in a detailed, disease severity-matched way; and to assess the diagnostic capabilities of GCIPL thickness parameters in discriminating NTG or POAG from normal subjects. METHODS: A total of 157 eyes of 157 subjects, including 57 normal eyes, 51 eyes with POAG and 49 eyes with NTG were enrolled and strictly matched in age, refraction, and disease severity between POAG and NTG groups. The average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness, and the average, superior, temporal, inferior, and nasal retinal nerve fiber layer (RNFL) thickness were obtained by Cirrus optical coherence tomography (OCT). The diagnostic capabilities of OCT parameters were assessed by area under receiver operating characteristic (AUROC) curves. RESULTS: Among all the OCT thickness parameters, no statistical significant difference between NTG group and POAG group was found (all P>0.05). In discriminating NTG or POAG from normal subjects, the average and inferior RNFL thickness, and the minimum GCIPL thickness had better diagnostic capabilities. There was no significant difference in AUROC curve between the best GCIPL thickness parameter (minimum GCIPL) and the best RNFL thickness parameter in discriminating NTG (inferior RNFL; P=0.076) and indiscriminating POAG (average RNFL; P=0.913) from normal eyes. CONCLUSION: Localized GCIPL loss, especially in the inferior and inferotemporal sectors, is more common in NTG than in POAG. Among all the GCIPL thickness parameters, the minimum GCIPL thickness has the best diagnostic performance in differentiating NTG or POAG from normal subjects, which is comparable to that of the average and inferior RNFL thickness.     

Specificity and sensitivity of glaucoma detection in the Japanese population using scanning laser polarimetry.

AIMS: To investigate the usefulness of the scanning laser polarimeter (GDx; GDx Nerve Fiber Analyzer) for glaucoma detection in the Japanese population, and to investigate the difference in the thickness of retinal nerve fibre layer (RNFL) between normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). METHODS: 69 eyes of 69 normal subjects and 115 eyes of 115 chronic open angle glaucoma patients (60 NTG and 55 POAG patients) were studied. The thickness of RNFL was measured with GDx. An eye was diagnosed as glaucomatous, if at least one original GDx variable showed p <5%. The difference in thickness of RNFL between the NTG and POAG groups was then investigated. RESULTS: 46 normal eyes (66.7%) were diagnosed as not glaucomatous (no variables showing p <5%), and 93 glaucomatous eyes (46 NTG and 47 POAG eyes) (80.9%) were diagnosed as glaucomatous. Actual values of average thickness, ellipse average, superior average, and superior integral were significantly lower in the POAG group than those in the NTG group. CONCLUSIONS: New variables which elucidate focal RNFL defects or early changes are needed to improve the moderate detection ability found in this present study. The pattern of the change in RNFL may differ in NTG and POAG groups.     

Systemic arterial stiffness in glaucoma patients

PURPOSE: To investigate systemic arterial stiffness in glaucoma patients. SUBJECTS AND METHODS: One hundred and forty glaucoma patients and 121 control subjects were enrolled in the study. Among these subjects, 51 glaucoma patients [normal-tension glaucoma (NTG), 31; primary open angle glaucoma or ocular hypertension (POAG/OH): 20] and 61 control subjects without glaucoma, who presented with no risk factors for arteriosclerosis, were extracted for further analysis of systemic arterial stiffness by glaucoma type. Subjects presenting with risk factors for arteriosclerosis were classified into group A, and those presenting with no risk factors were classified into group B. Brachial-ankle pulse wave velocity (baPWV), a marker of systemic arterial stiffness, was determined with a volume-plethysmographic apparatus. The correlation between baPWV and mean deviation obtained from Humphrey Field Analyzer program 30-2 test was compared between 13 each of age-matched and sex-matched NTG and POAG/OH patients. RESULTS: There was a significant difference in baPWV between groups A and B [P<0.0001; 1748+/-393 cm/s (group A) and 1467+/-282 cm/s (group B)]. The baPWVs of control, NTG patients, and POAG/OH patients with no risk factors showed no significant difference. baPWV was positively correlated with age in all the 3 groups, but there were no significant differences among the 3 groups. baPWV tended to be negatively correlated with mean deviation in NTG patients (r2=0.25, P=0.08); in contrast, no correlation was observed in POAG/OH patients. CONCLUSION: Systemic arterial stiffness seems not to be strongly associated with glaucoma.     

Study of retinal nerve fiber layer thickness within normal hemivisual field in primary open-angle glaucoma and normal-tension glaucoma

PURPOSE: To determine if nerve fiber layer thickness (NFLT) in glaucoma patients decreases before the development of visual field loss, and if there is a difference in the thinning of NFLT between primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) eyes. METHODS: Thirty patients (33 eyes) with POAG and 31 patients (31eyes) with NTG, who had visual field defects localized in either the upper or the lower hemifield verified by Humphrey Field Analyzer (HFA), were measured for NFLT by scanning laser polarimetry (Nerve Fiber Analyzer). Twenty-three normal subjects (23 eyes) matched in refraction and age with the glaucoma patients were recruited as the control group. The total deviation (TD) in each hemifield obtained by HFA and the 180 degrees NFLT of each corresponding hemifield was calculated. Relationships between the TD of the normal or abnormal visual hemifield and the NFLT of the corresponding hemifield were compared among the POAG, NTG, and control groups. RESULTS: The NFLT of the corresponding normal hemifield was decreased both in the POAG group and in the NTG group when compared with the corresponding measurements in control subjects. In POAG eyes, thinning of the NFLT in the corresponding normal hemifield was more remarkable if the TD of the abnormal hemifield was greater, but this tendency was not observed in NTG eyes. CONCLUSION: NFLT is already decreased when the visual field is still normal both in POAG eyes and in NTG eyes. However, the pattern of retinal nerve fiber layer damage in POAG may differ from that in NTG.     

Relationship between corneal thickness and measured intraocular pressure in a general ophthalmology clinic

OBJECTIVE: To assess whether central corneal thickness (CCT) is a confounding factor in the classification of patients attending for glaucoma assessment in a district general hospital. DESIGN: Cross-sectional study by a single observer. PARTICIPANTS: Patients attending a general ophthalmic clinic: 235 clinically normal eyes, 52 eyes with normal-tension glaucoma (NTG), 335 eyes with primary open-angle glaucoma (POAG), 12 eyes with pseudoexfoliative glaucoma (PXE), 42 eyes with chronic angle closure glaucoma (CACG), and 232 glaucoma suspect (GS) eyes. INTERVENTION: Central corneal thickness was measured using ultrasonic pachymetry. MAIN OUTCOME MEASURE: Correlation of CCT and diagnosis. RESULTS: Mean CCT was 553.9 microm (95% confidence intervals [CI] for the mean, 549.0-558.8 microm) in the clinically normal eyes, 550.1 microm (95% CI, 546.6-553.7 microm) in the POAG eyes, 514.0 microm (95% CI, 504.8-523.3 microm) in the NTG eyes, 530.7 microm (95% CI, 511.2-550.1 microm) in the PXE eyes, 559.9 microm (95% CI, 546.8-573.0 microm) in the CACG eyes, and 579.5 microm (95% CI, 574.8-584.1 microm) in the GS eyes. The differences of mean CCT between the groups were highly significant (P< 0.001 analysis of variance). Eighty-five percent of eyes with NTG and only 36% of eyes with POAG had a mean CCT of 540 microm or less. Thirteen percent of eyes with POAG and 42% of GS eyes had a mean CCT greater than 585 microm. CONCLUSIONS: The CCT measurement is desirable in patients attending for glaucoma assessment in a district general hospital to avoid misclassification resulting from the relationship between CCT and tonometric pressure. Central corneal thickness alone is not an accurate predictor for the clinical diagnosis in this group of eyes. However, many eyes diagnosed as having NTG have thin corneas, which would tend to lower the tonometrically recorded intraocular pressure (IOP), so the finding of a less-than-normal thickness cornea introduces some doubt as to the diagnosis of NTG. For the GS eyes, most eyes had thick corneas, which would tend to increase the tonometrically recorded IOP. Thus, GS eyes with modest elevation of IOP and a thick cornea may be at low risk of progressing to POAG. Thus, many patients with "high IOPs" and a thick CCT do not necessarily have high IOPs and may not need to be followed as GS eyes.     

Combined phacoemulsification and goniotrephination in primary open-angle glaucoma and pseudoexfoliation glaucoma - a retrospective analysis

BACKGROUND: During the last few years combined cataract and glaucoma surgery is an established method to control intraocular pressure (IOP) and visual rehabilitation in patients with cataract and glaucoma. Despite this, there are currently only few data concerning the results of combined surgery for primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG). PATIENTS AND METHODS: To study the course of PEXG and POAG with respect to IOP regulation and visual acuity, 100 eyes with POAG (72 patients) and 22 with PEXG (19 patients) were evaluated which underwent a combined phacoemulsification and goniotrephination between 1993 and 1997. All patients had no glaucoma or other ocular surgery before. The mean follow up after operation was 39.5 (range 16 - 72) months. RESULTS: The mean preoperative IOP in PEXG (31.8 +/- 10.3 mm Hg) was significantly higher than in the POAG group (25.3 +/- 6.4 mm Hg) (p=0.0004). At follow up IOP decreased to 16.7 +/- 2.8 mm Hg (POAG) and 15.1 +/- 4.0 mm Hg (PEXG) (p < 0.0001). The absolute IOP lowering effect was significantly better for PEXG than for POAG (p=0.0003). All patients received medical treatment before surgery, whereas at follow up 59.0 % (POAG) and 81.8 % (PEXG) were untreated. The median preoperative visual acuity for the POAG was 0.32 (PEXG 0.25), visual outcome 0,63 (PEXG 0.5). CONCLUSION: The combined cataract and glaucoma surgery is a successful method of IOP control and visual rehabilitation. It seems that there is a tendency for a better efficiency and an untreated IOP regulation after surgery for PEXG. Thereby early surgical intervention could be an advantage for this glaucoma entity.     

GDxVCC检测原发性开角型与可疑青光眼视网膜神经纤维层损害的对比研究

目的采用GDxVCC系统检测正常人、可疑开角型青光眼(suspected open angle glaucoma，SOAG)以及原发性开角型青光眼(primary open angle glaucoma，POAG)患者的视盘周围视网膜神经纤维层(retinal nerve fiber layer，RNFL)厚度，并进行对比分析，探讨GDxVCC系统在青光眼早期诊断中的价值。设计前瞻性对照研究。研究对象42例SOAG，36例POAG以及年龄相匹配的36例正常人参加此项研究。方法所有参加者进行视野与GDxVCC系统检查，选择一眼进行分析。采用方差分析，对SOAG、POAG、正常人的RNFL参数进行两两比较。主要指标GDxVCC检测RNFL厚度。结果POAG组与正常组问所有RNFL参数差异均有极显著意义(P=0．000)；POAG组与SOAG组间所有RNFL参数差异均有极显著意义(P=0．000)；SOAG组与正常组间椭圆平均值差异无统计学意义(P=0．234)，但其上方平均值与下方平均值及神经纤维指数差异均有统计学意义(P=0．044、P=0．045、P=0．035)，TSNIT标准差有极显著意义(P=0．000)。结论GDxVCC系统能更早地发现青光眼性RNFL结构损害，不仅可用于青光眼诊断和随访，亦可用于对可疑青光眼进行追踪。     

Central corneal thickness determined with optical coherence tomography in various types of glaucoma

AIMS: To evaluate central corneal thickness determined by optical coherence tomography (OCT) in various types of glaucoma, and its influence on intraocular pressure (IOP) measurement. METHODS: Central corneal thickness (CCT) was determined by using OCT in 167 subjects (167 eyes). 20 had primary open angle glaucoma (POAG), 42 had low tension glaucoma (LTG), 22 had ocular hypertension (OHT), 10 had primary angle closure glaucoma (AC), 24 had pseudoexfoliation glaucoma (PEX), 13 had pigmentary glaucoma (PIG), and 36 were normal. RESULTS: CCT was significantly higher in ocular hypertensive subjects (593 (SD 35) microm, p <0.0001) than in the controls (530 (32) microm), whereas patients with LTG (482 (28) microm, p < 0. 0001), PEX (493 (33) microm, p <0.0001), and POAG (512 (30) microm, p <0.05) showed significantly lower readings. There was no statistically significant difference between the controls and patients with PIG (510 (39) microm) and AC (539 (37) microm). CONCLUSIONS: Because of thinner CCT in patients with LTG, PEX, and POAG this may result in underestimation of IOP, whereas thicker corneas may lead to an overestimation of IOP in subjects with OH. By determining CCT with OCT, a new and precise technique to measure CCT, this study emphasises the need for a combined measurement of IOP and CCT in order to obtain exact IOP readings.     

高眼压性和正常眼压性原发性开角型青光眼视神经损害特征的比较

目的探讨高眼压性原发性开角型青光眼(POAG)和正常眼压性青光眼(NTG)患者视神经损害的不同特点。方法应用德国Heidelberg公司生产的视网膜断层扫描仪对高眼压性POAG39例(47只眼)和NTG32例(38只眼)进行定量视盘参数和神经纤维层检查,并行眼底立体照相观察视网膜神经纤维层(RNFL)缺损类型,检测静态定量视野,并对检查结果进行比较。结果(1)NTG组视盘总体参数和分区(除颞侧外)盘沿面积、沿/盘面积小于高眼压性POAG组,而C/D大于高眼压性POAG组;平均RNFL厚度和RNFL面积在颞下和颞上小于高眼压性POAG组;总体盘沿容积小于高眼压性POAG组,总体平均视杯深度和颞下视杯面积大于高眼压性POAG组,两组差异均有统计学意义(P<005)。两组颞侧视盘各参数比较,差异无统计学意义(P>005)。(2)RNFL缺损类型高眼压性POAG组RNFL弥漫性缺损占5319%,局限性缺损占426%;NTG组弥漫性缺损占2105%,局限性缺损占5526%。两组RNFL缺损类型构成比比较,差异有统计学意义(P<001)。结论NTG较高眼压性POAG具有较大的C/D值、C/D面积比和窄盘沿面积,RNFL丢失严重。高眼压性POAG患者的RNFL以弥漫性缺损为主,NTG患者的RNFL以局限性缺损为主。两者视神经损害具有不同特点,其损害机制可能不同。(中华眼科杂志,2005,41136140)     

Intraocular retinal thickness asymmetry in early stage of primary open angle glaucoma and normal tension glaucoma

AIM: To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer (pRNFL) and macular layers measured by spectral-domain optical coherence tomography (SD-OCT) in patients with early stage of primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). METHODS: A total of 117 patients with early stage of glaucoma (54 patients with POAG and 63 patients with NTG) and 32 normal subjects were recruited for the study. The pRNFL thickness, total macular layer (TML) thickness, and isolated inner macular layer (IML) thickness were measured by SD-OCT. Hemisphere TML thickness asymmetry measured by the posterior pole asymmetry scan was evaluated. Thickness differences of pRNFL and IML between superior and inferior quadrants were calculated. Asymmetry indices (AIs) of the pRNFL, TML and isolated IML were also computed. Areas under the receiver-operating characteristic curves (AROCs) were generated to determine the diagnostic capabilities of different parameters. RESULTS: Intraocular pRNFL thickness differences and AIs between the superior and inferior quadrants were significantly different between normal and NTG groups (P=0.009 and P<0.001, respectively). Intraocular pRNFL thickness differences and AIs between the temporal-superior and temporal-inferior sectors were also significantly different between normal and NTG groups (P=0.035 and P<0.001, respectively). The thickness differences and AIs of TML between superior and inferior hemispheres were significantly different between normal and NTG groups (P=0.001 and P=0.001, respectively) and between normal and POAG groups (P=0.032 and P=0.020, respectively). The thickness differences and AIs of macular ganglion cell layer (mGCL) between superior and inferior quadrants were significantly different between normal and NTG groups (P=0.013 and P=0.004, respectively), and between NTG and POAG groups (P=0.015 and P=0.012, respectively). The thickness difference of TML between superior and inferior hemispheres showed the highest diagnostic capability for early NTG eyes (AROC=0.832). CONCLUSION: Intraocular retinal thickness asymmetry in pRNFL, TML and mGCL are found in early stage of NTG. Hemisphere TML thickness asymmetry is also found in POAG eyes. Asymmetry analysis of retinal thickness can be an adjunctive modality for early detection of glaucoma.