Maximum Cup Depth Research Articles

Analysis of peripapillary retinal nerve fiber layer thickness and papillary parameters in different degrees of myopic eyes

Background Myopia is an important risk factor of glaucoma.Investigation of the characteristics of retinal nerve fiber layer thickness (RNFLT) and optical head morphology in myopia patients was helpful for differentiating myopic change and glaucomatous change in myopic eye.Objective This study was to investigate the peripapillary RNFLT and papillary parameters in different degrees of myopic eyes.Methods A 5-year case series study was retrospectively analyzed.Total 168 eyes of 168 myopic patients without visual field defect were recruited and divided into three age matched groups according to spherical equivalent (SE):low myopia group (SE:-0.25 ～-0.75 D) (57 eyes),moderate myopia group (SE:-3.0 ～-5.75 D) (57 eyes) and high myopia group (SE:-6.0～-12.0 D) (54 eyes).The RNFLT was measured with scanning laser polarmetry (GDxVCC) and papillary parameters measured with confocal scanning laser ophthalmoscope (HRT Ⅱ).Intergroup difference of parameters from GDxVCC and HRT Ⅱ were analyzed using one-way analysis of variance and SNK-q test.The correlations between spherical equivalent and RNFLT or papillary parameters was evaluated with multiple linear regression analysis.Results The global average,superior and inferior average,standard deviation,inter-eye symmetry of RNFLT were gradually reduced as the increase of SE with significant differences among the three groups (F=6.193,7.127,3.874,4.098,3.128,P ＜ 0.05).Global average,superior average,standard deviation,inter-eye symmetry of RNFLT were significantly lower in the high myopia group than those in the low myopia group (q =5.334,4.526,4.586,20.679,P＜0.05).An statistically significant reduce in inter-eye symmetry was seen between the high myopia group and the moderate myopia group (q =6.225,P＜0.05) as well as between the moderate myopia group and the low myopia group (q =10.035,P＜0.05).The multiple regression analysis showed that global average,superior average,inferior average,standard deviation,inter-eye symmetry of the R NFLT decreased with the increase of SE (β=0.441,t=6.329,P=0.000;β=0.471,t=6.880,P=0.000;β=0.339,t=4.641,P=0.000;β=0.389,t=5.445,P =0.000 ; β =0.338,t =4.621,P =0.000).Cup volume,linear cup/disk ratio,mean cup depth and maximum cup depth in the high myopia group were significantly lower than those of the moderate myopia groups (q =2.603,P =0.0l 1 ;q =2.105,P =0.037 ; q =2.825,P =0.006 ; q =2.495,P =0.014).Mean cup depth and height variation contour were significantly decreased in the high myopia group compared with the low myopia group (q =2.562,P =0.013 ;q =2.203,P =0.030).Rim area,rim volume,height variation contour were positively correlated with the degree of myopia (β=0.195,t=-2.565,P=0.011 ;β=0.199,t=-2.611,P=0.010;β=0.177,t =-2.311,P=0.022) ; while mean cup depth were negatively correlated with the degree of myopia (β =0.153,t =1.997,P =0.047).Conclusions As the increase of myopia degree,superior and inferior quadrants of RNFLT and cup depth are declined,but rim volume is elevated.Myopia is a confounding factor when RNFL data is interpreted by GDxVCC and papillary parameter by HRT Ⅱ. Key words: Biometry; Myopia; Retina nerve fiber layer thickness; Papillary contour

The Heidelberg retina tomograph ancillary study to the European glaucoma prevention study: study design and baseline factors

To describe the study design and baseline factors of the Heidelberg Retina Tomograph ancillary study within the EGPS. Furthermore, to examine the relationship between HRT optic disc topographic measurements and baseline demographic and ocular factors. Four hundred and eighty-nine ocular hypertensive participants were included. Each participant completed HRT imaging at least annually. The associations between HRT measurements and IOP, central corneal thickness (CCT), baseline photographic estimates of vertical CDR ratio (CDR), asymmetry between the two eyes in CDR ratio and baseline visual field indices were assessed using regression analysis. Associations between HRT measurements and vertical CDR by photographs were found for almost all stereometric optic disc parameters in both univariate and multivariate analysis. The strongest association was found between vertical CDR measurements and disc, cup and rim area; cup and rim volume, CDR area, linear CDR, mean and maximum cup depth and cup shape measure (all p < 0.0001). In multivariate analysis, pattern standard deviation (PSD) and HRT disc area had significant associations with several HRT optic disc measurements. Furthermore, CCT was significantly associated with reference height and the glaucoma probability score (GPS, outside normal limits). The EGPS is the first multicentre, placebo-controlled randomized clinical trial to use HRT for monitoring optic disc changes in participants with ocular hypertension. We found strong associations between stereophotographic vertical CDR estimates, HRT disc area, PSD and several HRT parameters. We found, furthermore, that the parameters reference height and GPS were significantly related to central corneal thickness.

Comparison of Spectral-Domain Optical Coherence Tomography and Heidelberg Retina Tomograph III Optic Nerve Head Parameters in Glaucoma

Background: To evaluate the agreement between the optic nerve head (ONH) measurements obtained by spectral-domain optical coherence tomography/scanning laser ophthalmoscope (SD-OCT/SLO) and the Heidelberg retinal tomograph III (HRT-III), and to compare the ONH measurements of both devices in different glaucoma types. Methods: In a prospective study, 30 patients with primary open-angle glaucoma (POAG) and 30 patients with pseudoexfoliation glaucoma (PXG) were enrolled. All patients underwent SD-OCT/SLO and HRT-III evaluation of the ONH during the same visit. Agreement between measurements of SD-OCT/SLO and HRT-III were evaluated by determination of intraclass correlation coeficients. In addition, mean ONH measurements obtained with both devices were compared between POAG and PXG patient groups. Results: Mean SD-OCT/SLO measurements were greater than those of HRT-III, except for mean and maximum cup depth. Intraclass correlation coefficient values for disc area, rim area, cup area, cup/disc area ratio, mean cup depth and maximum cup depth were 0.367, 0.213, 0.632, 0.681, 0.775 and 0.661, respectively. No significant differences were found between ONH parameters of POAG and PXG patients as measured with both devices (p > 0.01). Conclusion: ONH measurements with SD-OCT/SLO and HRT-III did not show clinically acceptable agreement in glaucoma patients. This precludes interchangeable use of these measurements in clinical practice. PXG and POAG patient groups displayed similar ONH measurements with both devices.

Optic Disc and Retinal Nerve Fiber Layer Parameters of Eyes With Keratoconus

To evaluate optic nerve head (ONH) characteristics and retinal nerve fiber layer (RNFL) thickness measurements in patients with nonglaucomatous keratoconus. This was a cross-sectional, observational study in which 46 patients with keratoconus and 74 healthy subjects were included. Analysis of ONH and RNFL imaging were performed by confocal scanning laser ophthalmoscopy and optical coherence tomography, respectively. Eyes with keratoconus had larger disc area (2.37 ± 0.5 vs 2.17 ± 0.36 mm(2)) (P = .013), larger cup area (0.65 ± 0.53 vs 0.49 ± 0.28 mm(2)) (P = .035) and deeper cup depths (for mean cup depth 0.24 ± 0.09 vs 0.20 ± 0.07 mm, P = .008 and for maximum cup depth 0.69 ± 0.27 vs 0.60 ± 0.17 mm, P = .037) than control group eyes. Height variation contour also differed in the two groups (P = .007) but RNFL measurements did not. RNFL thickness between patients with keratoconus and healthy subjects seems to be more comparable than ONH parameters.

OPTIC DISK ANALYSIS WITH HEIDELBERG RETINA TOMOGRAPHY IN PATIENTS WITH BRANCH RETINAL VEIN OCCLUSION

To investigate the optic disk topography parameters of patients with branch retinal vein occlusion (BRVO) in a controlled study by using Heidelberg retinal tomography. This prospective study included 35 eyes of 30 patients with BRVO who were followed-up at the Retina Clinic of the Ankara Ulucanlar Eye Education and Research Hospital, and 30 normal subjects (60 eyes). All patients and control subjects underwent complete ophthalmologic evaluation. The optic nerve heads of all subjects were imaged with the Heidelberg retinal tomography III (software 3.01a-M). The following stereometric parameters were calculated for each patient: disk area, cup area, cup-to-disk ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth, and cup shape measure. Differences between the two groups were evaluated by the nonparametric independent sample t-test. The mean cup volume, rim volume, cup area, disk area, rim area, and cup depth in BRVO group were found to be statistically significantly smaller than those in the control group (P < 0.05). Significant differences in the same parameters were also noted between the unaffected and affected eyes in patients with BRVO (P < 0.05). No significant differences were found between the groups in terms of the other stereometric parameters (P > 0.05). Based on the results that were obtained in this series, a relationship was found between BRVO and various optic disk topography parameters determined by Heidelberg retinal tomography. Anatomical features of the optic disk may play a role in the pathogenesis of BRVO.

Optic disc assessment using confocal scanning laser ophthalmoscope in normal tension glaucoma with disc hemorrhage

AbstractPurpose To evaluate which optic disc parameters have a relationship with the presence and the location of disc hemorrhages in normal tension glaucoma (NTG)Methods This retrospective study included patients with early NTG with mean deviation with – 10 dB or better in 24‐2 Humphrey visual field analyzer. Eyes in the whole study group were divided into those with and without disc hemorrhage. Optic disc stereometric parameters measured using the Heidelberg Retina Tomograph (HRT) III were compared between each group with and without disc hemorrhage. Within the group with disc hemorrhage, the location of disc hemorrhage was analyzed. Sectoral disc parameters were compared between two common locations where disc hemorrhage developed.Results Forty‐three patients with disc hemorrhage and 46 patients without disc hemorrhage were included in this study. Mean deviation and pattern standard deviation showed no significant difference between two groups. There was no significant difference in global optic disc parameters of HRT between two groups. Disc hemorrhage was displayed mainly in inferotemporal (23 eyes, 53.5%) and in superotemporal (12 eyes, 27.9 %). Regarding to sectoral disc analysis of inferotemporal quadrant, the value of cup shape measure and cup disc area ratio was higher in the disc hemorrhage group compared to the group without disc hemorrhage (P=0.0013, P=0.013, repectively). The subset analysis of disc parameters within the disc hemorrhage group, showed that superotemporal maximum cup depth in eyes with superotemporal disc hemorrhage was greater compared to inferotemporal maximum cup depth in eyes with inferotemporal disc hemorrhage (P=0.017).Conclusion The change of optic disc parameters in early NTG patients with disc hemorrha Commercial interest

Topographic Differences between Large and Normal Optic Discs: A Confocal Scanning Laser Ophthalmoscopy Study

The aim of the study was to investigate the optic nerve head parameters of healthy macrodiscs to provide standard measurements for them to be the basis for future quantitative comparisons. Sixty-nine subjects with macrodisc (disc area larger than 2.82 mm(2)) and 91 healthy controls (disc area between 1.16 and 2.82 mm(2)) were recruited. After a complete ophthalmic examination, confocal scanning laser ophthalmoscopy was performed in all participants. The stereometric parameters of confocal scanning laser ophthalmoscopy examination and the proportion of subjects classified as normal, borderline, and glaucomatous by the Moorfield Regression Analysis were compared between groups. A total of 160 subjects were included in the study. The average disc sizes in the control and macrodisc groups were 2.14 ± 0.33 mm(2) and 3.36 ± 0.36 mm(2), respectively. Cup area (p<0.001), rim area (p=0.01), cup volume (p<0.001), cup/disc area ratio (p<0.001), linear cup/disc ratio (p<0.001), mean cup depth (p<0.001), maximum cup depth (p<0.001), and cup shape measure (p<0.001) differed significantly between the 2 groups. The parameters of the optic nerve head which did not differ significantly between groups were rim volume (p=0.17) and height variation contour (p=0.88). A significantly higher number of eyes were erroneously identified as abnormal (15.1% vs 79.4%) by Moorfield Regression Analysis in the macrodisc group (p<0.001). Rim volume and height variation contour were the only optic nerve head topographic parameters that were similar in eyes with large and normal disc sizes. They seem to be promising parameters in the evaluation and comparison of the optic nerve head of subjects with macrodisc.

Optic disc topography in normal Indian eyes using spectral domain optical coherence tomography

Purpose:The aim was to study optic nerve head (ONH) parameters in normal Indian eyes using spectral domain optical coherence tomography (OCT)/scanning laser ophthamoscope (SLO).Materials and Methods:One hundred and fifty-seven eyes of 157 normal subjects of various age groups underwent ONH imaging with spectral OCT/SLO and the parameters obtained were correlated with disc size. The effect of age, gender, and refractive error on various ONH parameters were also studied.Results:The mean optic disc area was 3.36 ± 0.64 mm2 (range, 2.13–5.08 mm2), mean rim area was 2.49 ± 0.58 mm2 (range, 1.20–3.62 mm2), and mean cup area was 1.10 ± 0.75 mm2 (range, 0–3.07 mm2). The disc area showed significant positive correlation with the rim area, cup area, horizontal cup disc ratio, vertical cup disc ratio, cup disc area ratio, mean cup depth, and maximum cup depth (P < 0.001). Neither gender nor refractive error showed any significant difference in various ONH parameters. ONH parameters did not show significant change with age except for rim area which declined with the advancing age (r = –0.25, P < 0.001).Conclusions:The quantitative measurement of ONH topography obtained with this study provides a normative database for an Indian population with spectral OCT/SLO. As optic disc area influences ONH topography, disc size should to be considered when evaluating optic disc for progressive optic neuropathies such as glaucoma.

Assessment of optic disc parameters among healthy adult Malays by Heidelberg Retinal Tomograph II

This study aims to assess the optic disc characteristics in healthy adult Malays and to correlate them with age, gender and refractive errors. Cross-sectional study. A total of 200 voluntary participants (106 women and 94 men) among Malay students aged 20 to 37 years at Health Campus, Universiti Sains Malaysia. The relationship between Heidelberg Retinal Tomograph parameters with age, gender and refractive error were analysed with correlation tests and multiple linear regression analyses. Twelve parameters, that is, disc area, rim area, cup area, cup to disc area, cup volume, rim volume, height variation contour, cup shape measure, mean cup depth, maximum cup depth, mean retinal nerve fibre layer thickness and retinal nerve fibre layer cross-sectional area. Disc area, rim area and cup : disc area ratio averaged 2.24 ± 0.52 (mean ± standard deviation), 1.64 ± 0.32 and 0.25 ± 0.12 mm(2) , respectively. Five parameters (disc area, cup area, cup volume, cup : disc area ratio and mean retinal nerve fibre layer thickness) showed statistically significant difference between men and women. Age was negatively and significantly correlated with rim area with coefficient r = -0.21, P = 0.003. All optic disc parameters were significantly correlated (P < 0.05) with disc area, except cup shape measure. One or more of optic disc parameters were affected significantly by age, gender and disc area in healthy adult Malays' eyes. These factors need to be considered during the evaluation of optic disc.

Correlation between morphology of optic disc determined by Heidelberg Retina Tomograph II and visual function in eyes with open-angle glaucoma

To investigate the correlation between the morphology of the optic disc and the visual function of eyes with open-angle glaucoma (OAG). One hundred and three eyes of 76 patients with OAG were studied. The baseline optic disc morphology was used to classify the eyes into four types: focal ischemic type (FI), myopic glaucomatous type (MY), senile sclerotic type (SS), and generalized enlargement type (GE). The morphological parameters of the disc were determined by the Heidelberg Retina Tomograph II (HRT-II) and the visual function by the mean deviation (MD) of the Humphrey field analyzer. Fourteen eyes were classified as the FI type; 52 as the MY type; 17 as the SS type; and 20 as the GE type. The highest correlation coefficients of HRT-II parameters to the MDs was the cup/disc area ratio (r = -0.27) for all groups, the vertical cup/disc ratio (r = -0.42) in the MY group, the maximum cup depth (r = 0.49) in the SS group, and the cup area (r = -0.70) in the GE group. However, none of the parameters was correlated in the FI group. The correlation between the HRT-II parameters and MDs was different for the four disc types. These findings suggest that a classification of optic disc morphology had a benefit for interpreting the measured values of HRT-II.

Reproducibility of OCT/SLO Measurements in Healthy Eyes

To determine the reproducibility of optical coherence tomography/scanning laser ophthalmoscope (OCT/SLO) measurements within and between observers and within and between sessions in healthy eyes. Forty eyes of 40 healthy volunteers recruited from the outpatient service of the Department of Ophthalmology at the University Hospital of Alexandroupolis, Greece, were included. Retinal thickness scans were performed 3 times by two experienced operators within each of 3 sessions, which took place within a month, using the spectral OCT/SLO. The OCT/SLO provides retinal nerve fiber layer (RNFL) thickness and volume measurements and a 3D tomography analysis of optic nerve head. Statistical analysis was conducted using Bland-Altman plots, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). As shown by the CoV values, RNFL parameters were generally found to have high reproducibility (CoV ranging from 4.3% to 10.9% for both operators), whereas optic disc parameters had scores reaching up to 22.5%. On the other hand, as shown by the ICC values, intraobserver and interobserver reproducibility for the OCT/SLO was high for optic disc parameters but low for RNFL thickness and volume measurements. Interobserver reproducibility was found to be highest for the maximum cup depth parameter and lowest for the superior volume. Bland-Altman plots indicate that bias is minimal for practically all parameters and scatterplot homoscedasticity is high. According to our data, SLO/OCT generally has a good reproducibility profile, as differences between the two operators were small. However, additional studies on the reproducibility of measurements with the OCT/SLO are needed.

Vergleich papillenspezifischer Parameter einer europäischen und einer Bantu-Population

Glaucoma is the main cause of irreversible blindness in the world. Because of the increasing mean age, glaucoma is expected to become more common in the developing countries. Besides tonometry and perimetry the appearance of the optic nerve head is a main part of glaucoma diagnosis. Ethnic differences have to be considered. This study compares the appearance of the optic nerve head between blacks and whites. This is a retrospective analysis of 225 whites of a Swiss population and 1027 blacks of a Congolese population. Using a matched pairs technique 207 whites and 207 blacks were chosen, regarding age, sex, intraocular pressure and examined eye (right/left). The analysis of the optic nerve head was performed by using the "Heidelberg-Retina-Tomograph II" (HRT). Among the 207 persons of both groups we found 116 females and 91 males. There were 103 right eyes and 104 left eyes examined. The mean age was 45.6 +/- 15.6 years. Compared with European population in the African population we found a greater disc area (2.56 vs. 1.81 mm(2)) as well as a greater cup area (0.65 vs. 0.41 mm(2)) and a greater rim area (1.91 vs. 1.40 mm(2)). Regarding the cup disc area ratio there was no significant difference between both populations found (Kinshasa: 0.24 vs. Basel: 0.21). Although there was no significant difference of the maximum cup depth of both groups we found a deeper mean cup depth in the African population. Furthermore, we found differences regarding the cup shape measure, the RNFL thickness and the height variation contour. As already described in different studies, there are significant differences in the morphology of the optic nerve head between blacks and whites. Although blacks are expected to have a greater cup disc area ratio, this fact could not be proved in this study. As a new fact we found a different mean cup depth between Africans and Europeans, which might be explained by the different cup shape of both populations.

Heidelberg retina tomograph parameters of the optic disc in eyes with progressive retinal nerve fibre layer defects

To determine the Heidelberg retina tomograph (HRT) parameters that identify glaucomatous changes in optic nerve head (ONH) topography associated with progression of retinal nerve fibre layer (RNFL) defects. A total of 68 eyes with open-angle glaucoma were included in this retrospective study: 34 eyes showed progression of an RNFL defect during the follow-up period and 34 eyes did not. Successful RNFL photographs and scanning laser tomography examinations with the HRT were taken in all patients at each of three visits. The change in HRT parameter values during follow-up was calculated. Progression of the RNFL defect was statistically significantly correlated (p = 0.049) with only one topographic ONH parameter, the cup shape measure. The best combination of two parameters (p = 0.009) included the maximum cup depth and the linear cup : disc area ratio; the best combination of three parameters (p = 0.007) included the maximum cup depth, the linear cup : disc area ratio and the horizontal cup : disc area ratio. Sensitivity and specificity values were 52.9% and 73.5%, respectively, for the cup shape measure, 70.6% and 73.5%, respectively, for the two-parameter combination, and 76.5% and 79.4%, respectively, for the three-parameter combination. The areas under the receiver operating characteristic curve were 0.617, 0.724 and 0.753, respectively. The results indicate that the HRT parameters may be used to detect small ONH changes associated with progression of the RNFL defect. With the exception of the cup shape measure, the parameters which provide the best correlation with progression differ from those considered optimal for recognizing the presence or absence of glaucoma.

Relationship between Central Corneal Thickness and Parameters of Optic Nerve Head Topography in Healthy Subjects

To investigate the relationship between central corneal thickness (CCT) and topographic parameters of optic nerve head (ONH) in healthy eyes. Right eyes of 208 healthy subjects between 40 and 59 years of age with refractive error less than 1 D were enrolled in this cross-sectional study. Ultrasonic pachymeter was used to measure CCT, and the ONH parameters were obtained by using confocal scanning laser ophthalmoscope. Relationship of various topographic parameters to age and sex were also investigated. For statistical analysis Student t test, analysis of variance, Pearson and Spearman test, and partial correlation coefficients were used. Mean CCT of subjects was 540.71+/-35.53 micronm (462-621 micronm), and the mean disc area was 2.37+/- 0.44 mm2 (1.28-3.66 mm2). CCT showed negative correlations to disc area, rim area, rim volume, and retinal nerve fiber layer (RNFL) area. These correlations were found to be stronger in females. Negative correlations were demonstrated between age and the mean cup depth, maximum cup depth, RNFL thickness, and RNFL cross sectional area. Women had lesser rim volumes, but bigger cup to disk (C/D) area and linear C/D ratios compared to those of men. In addition to its effect in the accuracy of intraocular pressure measurements, CCT has a structural relationship with the ONH in healthy nonglaucomatous eyes. Therefore, its effect on disc area might be especially important to explain the structural strength of the ONH in the pathogenesis of glaucoma.

Interobserver variability in confocal optic nerve analysis (HRT)

To study the observer-related variability of optic nerve head (ONH) measurements using confocal laser scanning tomography (HRT I) in a screening setting. Six experienced glaucoma specialists independently evaluated 50 ONH topographies from 25 adults using HRT software ver. 2.01 in a masked fashion. ONH topographies were obtained from a cohort study of 882 healthy adults and additionally included one patient with glaucomatous eyes. A glaucoma-screening-like setting was intended. The mean interobserver difference was defined as the mean percentual difference between an observer's analysis and the mean of all six observers for all eyes and all observers. The interobserver range was calculated for each eye as the percentual difference between the lowest and highest measurement, with the highest measurement as denominator. Additionally, Kendall's coefficient of rank concordance was assessed for the main HRT parameters. Mean disc area ranged from 1.83 +/- 0.49 to 2.21 +/- 0.40 mm(2) (mean interobserver difference: 8.3%; interobserver range: 5-50%; rank concordance: 0.86). The lowest mean interobserver differences were found for mean retinal nerve fibre layer thickness (RNFLT; 6.5%), maximum cup depth (2.9%) and cup shape (6.8%). An increased interobserver range was significantly correlated to a low cup to disc area ratio (r=0.64, P<0.0001). The observer-dependent diagnostic variability of HRT measurements can lead to divergent diagnostic evaluation of the ONH in a screening setting. Any HRT software relying on a reference database is exposed to relevant observer-related variability of the disc area. For screening purposes, HRT measurements should be completed by other diagnostic methods to compensate for possible diagnostic uncertainty.

Comparison of optic nerve head topography in healthy adults using a Heidelberg retina tomograph and retinal thickness analyzer

To compare optic nerve head topographies measured using a Heidelberg retina tomograph I (HRT) and a retinal thickness analyzer (RTA) and thereby to determine clinical agreement between the two devices. Also, to investigate the reproducibility of optic nerve head measurements using the HRT and RTA. The study included 50 normal left eyes of 50 white adults. Ophthalmologic examination, keratometry, fundus photography, and examination with HRT and RTA were performed. To determine reproducibility, 10 volunteers had repeated examinations after a week. Mean (SD), median, and 5th and 95th percentiles were calculated for the HRT and RTA measurements and differences in measurements between HRT and RTA were tested for statistical significance. Clinical agreement was assessed with limits of agreement and reproducibility by a repeatability coefficient and intraclass correlation coefficient (ICC). Statistically significant differences (P < 0.05) between measurements by HRT and RTA were observed for all topographic parameters, except for rim area (P = 0.051) and height variation contour (P = 0.054). The limits of agreement between HRT and RTA were wide. The repeatability coefficient for HRT was good (< or =0.10) for all parameters, except for retinal nerve fibre layer (RNFL) cross-sectional area (0.28). The repeatability coefficient for RTA was >0.10 for cup area (0.15), rim area (0.19), maximum cup depth (0.13), height variation contour (0.11), and RNFL cross-sectional area (0.14). The ICC was good (> or =90%) for all parameters, except for mean RNFL thickness (89%) for HRT, and height variation contour (84%) for RTA. The observed differences within the limits of agreement were clinically important. Therefore, the two devices cannot be used interchangeably in clinical practice.

Relationship Between Central Corneal Thickness and Changes of Optic Nerve Head Topography and Blood Flow After Intraocular Pressure Reduction in Open-angle Glaucoma and Ocular Hypertension

To investigate changes in optic nerve head topography and blood flow after therapeutic intraocular pressure reduction and to correlate them with central corneal thickness. Sixteen patients with open-angle glaucoma and 16 patients with ocular hypertension underwent Heidelberg retina tomography and scanning laser Doppler flowmetry in 1 eye before and at least 2 months after a mean 35% sustained therapeutic reduction in intraocular pressure. Patients were assigned to a thin or thick group based on their median central corneal thickness. Compared with 16 patients with thick corneas (mean +/- SD central corneal thickness, 587 +/- 31 microm), the 16 patients with thin corneas (518 +/- 32 microm) had greater reductions in mean (36 +/- 32 vs 4 +/- 36 microm, P = .003) and in maximum cup depth (73 +/- 107 vs 4 +/- 89 microm, P = .02). These changes were not statistically significantly different between the patients with open-angle glaucoma and those with ocular hypertension. Smaller mean +/- SD improvements in neuroretinal rim blood flow were seen in patients with thinner corneas compared with those with thicker corneas (35 +/- 80 vs 110 +/- 111 arbitrary units, P = .04). Patients with open-angle glaucoma and ocular hypertension with thinner corneas show significantly greater shallowing of the cup, a surrogate marker for lamina cribrosa displacement (compliance), and smaller improvements of neuroretinal rim blood flow after intraocular pressure reduction.

Changes in the Optic Disc Excavation of Children Affected by Cerebral Visual Impairment: A Tomographic Analysis

To obtain quantitative data on the optic disc excavation in children affected by cerebral visual impairment (CVI) by using the Heidelberg Retinal Tomograph (HRT)-II (Heidelberg Engineering, Heidelberg, Germany). A total of 24 subjects affected by CVI (mean age, 7.28 years) were examined: 16 in alert conditions and 8 under general anesthesia. The following parameters of the optic nerve head were examined: disc area, cup area, rim area, cup volume, rim volume, cup-to-disc area ratio, mean cup depth, maximum cup depth, cup shape measure, and mean retinal nerve fiber layer (RNFL) thickness. The tomographic results in children with CVI were compared with those of 88 normal, alert subjects of similar age. The optic disc of patients with CVI appeared smaller than normal. Its excavation, however, was more pronounced. Several tomographic parameters were altered in CVI-affected subjects. Statistical analysis showed a highly significant probability in cup-to-disc area ratio (P < 0.01, both eyes), rim area (P < 0.01, both eyes), cup shape measure (P < 0.01, right eye; P < 0.01, left eye), and mean RNFL thickness (P < 0.01, right eye; P < 0.01, left eye). A novel observation was temporal atrophy of the optic nerve head in CVI. The data provide a tridimensional, objective evaluation of the anatomic alterations of the optic nerve head in children with CVI. Furthermore, tomographic standards for optic disc shape in normal children are set for the first time.

Confocal Scanning Laser Ophthalmoscopy of Eyes with Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose: To evaluate optic nerve head topography in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using confocal scanning laser ophthalmoscopy. Methods: Both eyes of patients with NAION were imaged using a Heidelberg retina tomograph (HRT II; version 1.5) several months after initial presentation, when the optic disc edema had settled. Data from the stereometric analysis of optic nerve heads of eyes with NAION were compared to those of fellow eyes without NAION and eyes of an age- and sex-matched control group. Stereometric parameter values of the fellow eyes were compared with those of the control group. Results: Average age of the 23 Caucasian patients was 57.96 ± 10.41 years (range: 28–71 years). Seven patients (30%) were female and 16 (70%) were male. Four patients (17%) had bilateral NAION. Cup area, cup volume, cup/disc area, linear cup/disc area, mean cup depth, maximum cup depth, mean retinal nerve fiber layer (RNFL) thickness, and RNFL cross-sectional area values were smaller in the NAION eyes than in the control eyes (p < 0.05). A comparison of the NAION eyes with their fellow eyes revealed lower mean cup depth, maximum cup depth, mean RNFL thickness, and RNFL cross-sectional area in the diseased eyes (p < 0.05). Moreover, cup area, cup volume, cup/disc area, linear cup/disc area, mean cup depth, maximum cup depth values were smaller in the fellow eyes than the control eyes (p < 0.05). Conclusion: Using an objective imaging method, confocal scanning laser ophthalmoscopy, eyes with NAION were shown to have a smaller cup volume and cup/disc area, but not a smaller optic disc area than control eyes.

Differences in optic disc topography between black and white normal subjects

To determine if differences in optic disc topography exist between blacks and whites independent of racial differences in the area of the scleral canal. Cross-sectional observational study. A cohort of 146 eyes from black subjects and 97 eyes from white subjects without detectable ocular disease. Reliable bilateral images were obtained using a retinal topographer. Mean values for all topographic parameters were compared both unadjusted and adjusted for differences in optic disc area and/or reference plane height. Comparisons of group differences for parameters and linear discriminant functions were adjusted for interocular dependence and multiple comparisons. Blacks had a significantly greater optic disc area (mean disc area in right eye: black subjects, 2.14 mm(2); white subjects, 1.96 mm(2) [P = 0.02]; mean disc area in left eye: black subjects, 2.18 mm(2); white subjects, 2.02 mm(2) [P = 0.04]). Most racial differences in optic disc parameters were not significant after adjustment for differences in optic disc area and reference plane height. However, eyes of black subjects demonstrated a deeper maximum cup depth than those of whites (P = 0.004), independent of differences in disc area and reference plane height. The values of linear discriminant functions did not differ significantly between racial groups, and the Moorfield classification correctly identified a similar proportion of subjects as normal in each racial group. Most of the normal variation in optic disc topography between blacks and whites seen with a retinal topographer is due to either differences in disc area or differences in reference plane height. However, small residual differences remain in cup depth independent of these parameters. These racial differences in optic disc structure should be considered in the statistical judgment of disease status based on these parameters. The Moorfield classification, which takes disc area into account, performed with similar specificity in each racial group.