Related Articles

Enhanced depth-imaging optical coherence tomography was used to measure choroidal thickness in subjects with normal vision, primary-open angle glaucoma, and normal tension glaucoma. No difference was found in choroidal thickness, suggesting a lack of relationship between choroidal thickness and glaucoma.

Purpose.

To compare choroidal thickness measurements among normal eyes, eyes with normal tension glaucoma (NTG), and those with primary open-angle glaucoma (POAG), and to correlate choroidal thickness with demographic and clinical ocular parameters.

Methods.

Choroidal thickness was measured with enhanced depth-imaging (EDI) optical coherence tomography (OCT) in one eye of 38 normal, 20 NTG, and 56 POAG subjects and compared among groups. The mean age was 69.3 ± 13.6 years (60.1 ± 13.4 years for normal subjects and 73.8 ± 11.3 years for glaucoma subjects; P < 0.001). Measurements were made at the fovea and in the temporal and nasal choroid every 0.5 mm up to 3 mm away from the fovea. Univariate and multivariate linear regression analyses were performed to assess the association between choroidal thickness and demographic and ocular parameters.

Results.

There were no differences in foveal, temporal, or nasal choroidal thickness between normal, NTG, and POAG subjects (all P > 0.05) after adjusting for age, axial length, and intraocular pressure. Similarly, glaucoma severity groups did not differ from each other in all choroidal thickness measurements (all P > 0.05). Age (β = −1.78; P < 0.001) was the most significant factor associated with subfoveal choroidal thickness in the entire group, followed by axial length (β = −11.8; P = 0.002).

Conclusions.

Choroidal thickness does not differ among normal, NTG, and POAG subjects, suggesting a lack of relationship between choroidal thickness and glaucoma based on EDI OCT measurements.

PURPOSE

To analyze the normal peripapillary choroidal thickness utilizing a commercial spectral domain optical coherence tomography (OCT) device and determine the inter-grader reproducibility of this method.

DESIGN

Retrospective, non-comparative, non-interventional case series.

PARTICIPANTS

Thirty-six eyes of 36 normal patients seen at the New England Eye Center between April and September 2010.

METHODS

All patients underwent high-definition scanning with the Cirrus HD-OCT. Two raster scans were obtained per eye, a horizontal and a vertical scan, both of which were centered at the optic nerve. Two independent graders individually measured the choroidal thickness. Choroidal thickness was measured from the posterior edge of the retinal pigment epithelium to the choroid-scleral junction at 500 μm intervals away from the optic nerve in the superior, inferior, nasal and temporal quadrants. Statistical analysis was conducted to compare mean choroidal thicknesses. Inter-grader reproducibility was assessed by intraclass correlation coefficient and Pearson’s correlation coefficient. Average choroidal thickness in each quadrant was compared to retinal nerve fiber layer (RNFL) thickness in their respective quadrants.

MAIN OUTCOME MEASURES

Peripapillary choroidal thickness, intraclass coefficient, Pearson’s correlation coefficient.

RESULTS

The peripapillary choroid in the inferior quadrant was significantly thinner compared to all other quadrants (p< 0.001). None of the other quadrants were significantly different from each other in terms of thickness. The inferior peripapillary choroid was significantly thinner compared to all other quadrants at all distances measured away from the optic nerve (p< 0.001). Generally, the peripapillary choroid increases in thickness the farther it was away from the optic nerve and eventually approaching a plateau. Intraclass correlation coefficient ranged from 0.62 to 0.93 and Pearson’s correlation coefficient ranged from 0.74 to 0.95 (p< 0.001). Neither RNFL thickness nor average age was significantly correlated with average choroidal thickness.

CONCLUSIONS

Manual segmentation of the peripapillary choroidal thickness is reproducible between graders suggesting that this method is accurate. The inferior peripapillary choroid was significantly thinner than all other quadrants (p< 0.001).

Purpose

To compare the peripapillary retinal nerve fiber layer (RNFL) thickness of normal patients and those with various glaucoma diseases by time domain (Stratus) and spectral domain (Spectralis) optical coherence tomography (OCT).

Methods

The RNFL thickness as measured by the Stratus and Spectral OCT was compared (paired t-test). The relationship and agreement of RNFL thickness between the two OCT modalities were evaluated by Pearson correlation, Bland-Altman plot, and area under the receiver operating characteristic curve.

Results

Two-hundred seventeen eyes of 217 patients, including twenty-four normal eyes, ninety-one glaucoma suspects, seventy-six normal tension glaucoma cases, and twenty-six primary open angle glaucoma cases (POAG) were analyzed. The peripapillary RNFL thicknesses as measured by Stratus OCT were significantly greater than those measured by Spectralis OCT. However, in quadrant comparisons, the temporal RNFL thickness obtained using Stratus OCT were significantly less than those obtained using Spectralis OCT. Correlations between RNFL parameters were strong (Pearson correlation coefficient for mean RNFL thickness = 0.88); a high degree of correlation was found in the POAG group. Bland-Altman plotting demonstrated that agreement in the temporal quadrant was greater than any other quadrant.

Conclusions

Both OCT systems were highly correlated and demonstrated strong agreement. However, absolute measurements of peripapillary RNFL thickness differed between Stratus OCT and Spectralis OCT. Thus, measurements with these instruments should not be considered interchangeable. The temporal quadrant was the only sector where RNFL thickness as measured by Spectralis OCT was greater than by Stratus OCT; this demonstrated greater agreement than other sectors.

Purpose

To determine the agreement between peripapillary retinal nerve fiber layer (RNFL) thickness measurements from Stratus time domain optical coherence tomography (OCT) and Cirrus spectral domain OCT (Carl Zeiss Meditec, Dublin, CA) in normal subjects and glaucoma patients.

Design

Evaluation of diagnostic test or technology.

Participants

One hundred thirty eyes from 130 normal subjects and glaucoma patients were analyzed. The subjects were divided into Normal (n=29), Glaucoma Suspect (n=12), Mild Glaucoma (n=41), Moderate Glaucoma (n=18), and Severe Glaucoma (n=30) by visual field criteria.

Methods

Peripapillary RNFL thickness was measured with Stratus Fast RNFL and Cirrus 200 x 200 Optic Disc Scan on the same day in one eye of each subject to determine agreement. Two operators used the same instruments for all scans.

Main Outcome Measures

Student paired t-testing, Pearson’s correlation coefficient, and Bland-Altman analysis of RNFL thickness measurements.

Results

The average age of the glaucoma group was significantly older at 68.3±12.3 years versus 55.7±12.1 years. The average RNFL thickness (mean ± SD, in μm) for each severity group with Stratus OCT was 99.4 ± 13.2, 94.5 ± 15.0, 79.0 ± 14.5, 62.7 ± 10.2, and 51.0 ± 8.9, corresponding to normal, suspects, mild, moderate, and severe subjects, respectively. For Cirrus OCT, the corresponding measurements were 92.0 ± 10.8, 88.1 ± 13.5, 73.3 ± 11.8, 60.9 ± 8.3, and 55.3 ± 6.6. All Stratus-Cirrus differences were statistically significant by paired t-testing (p < 0.001) except for the moderate group (p = 0.11). For average RNFL, there was a highly significant linear relationship between Stratus minus Cirrus difference and RNFL thickness as well (p < 0.001). Bland-Altman plots showed that the systematic difference of Stratus measurements are smaller than Cirrus at thinner RNFL values but larger at thicker RNFL measurements.

Conclusions

RNFL thickness measurements between Stratus OCT and Cirrus OCT cannot be directly compared. Clinicians should be aware that measurements are generally higher with Stratus than Cirrus except when the RNFL is very thin as in severe glaucoma. This difference must be taken into account if comparing measurements made with a Stratus instrument to those of a Cirrus instrument.

Through a structure-structure correlation analysis of focal macular and peripapillary SD-OCT regions in 57 subjects with glaucoma (or glaucoma suspicion), a color-coded map closely resembling the nerve fiber bundle pattern of retinal ganglion cells emerged.

Purpose.

To correlate the thicknesses of focal regions of the macular ganglion cell layer with those of the peripapillary nerve fiber layer using spectral-domain optical coherence tomography (SD-OCT) in glaucoma subjects.

Methods.

Macula and optic nerve head SD-OCT volumes were obtained in 57 eyes of 57 subjects with open-angle glaucoma or glaucoma suspicion. Using a custom automated computer algorithm, the thickness of 66 macular ganglion cell layer regions and the thickness of 12 peripapillary nerve fiber layer regions were measured from registered SD-OCT volumes. The mean thickness of each ganglion cell layer region was correlated to the mean thickness of each peripapillary nerve fiber layer region across subjects. Each ganglion cell layer region was labeled with the peripapillary nerve fiber layer region with the highest correlation using a color-coded map.

Results.

The resulting color-coded correlation map closely resembled the nerve fiber bundle (NFB) pattern of retinal ganglion cells. The mean r2 value across all local macular-peripapillary correlations was 0.49 (± 0.11). When separately analyzing the 30 glaucoma subjects from the 27 glaucoma-suspect subjects, the mean r2 value across all local macular-peripapillary correlations was significantly larger in the glaucoma group (0.56 ± 0.13 vs. 0.37 ± 0.11; P < 0.001).

Conclusions.

A two-dimensional (2-D) spatial NFB map of the retina can be developed using structure-structure relationships from SD-OCT. Such SD-OCT-based NFB maps may enhance glaucoma detection and contribute to monitoring change in the future.

Purpose

To assess the diagnostic efficacy of macular and peripapillary retinal thickness measurements for the staging of diabetic retinopathy (DR) and the prediction of disease progression.

Methods

In this prospective study, 149 diabetic patients (149 eyes) and 50 non-diabetic control subjects were included. Baseline optical coherence tomography was employed to measure retinal thickness in the macula (horizontal, vertical, and central) and the peripapillary zone (superior, inferior, nasal, and concentric to the optic disc). Seven baseline parameters were correlated with the DR stages identified by fluorescein angiography. Baseline retinal thickness was compared between groups of patients requiring panretinal photocoagulation (PRP) within 6 months (PRP group) and patients not requiring PRP (No-PRP group).

Results

Macular and peripapillary retinal thicknesses in diabetic subjects were significantly greater than that in normal controls (p<0.05). All retinal thickness parameters, and particularly peripapillary circular scans, tended to increase with increasing DR severity (p<0.05). The baseline thicknesses of the peripapillary circular scans were greater in the PRP group than in the no-PRP group (p<0.05).

Conclusions

Peripapillary retinal thickness may prove to be a useful criterion for DR severity and may also serve as an indicator of disease progression.

Purpose

To determine the ability of optic nerve head (ONH) parameters measured with spectral domain Cirrus™ HD-OCT to discriminate between normal and glaucomatous eyes and to compare them to the discriminating ability of peripapillary retinal nerve fiber layer (RNFL) thickness measurements performed with Cirrus™ HD-OCT.

Design

Evaluation of diagnostic test or technology.

Participants

Seventy-three subjects with glaucoma and one hundred and forty-six age-matched normal subjects.

Methods

Peripapillary ONH parameters and RNFL thickness were measured in one randomly selected eye of each participant within a 200×200 pixel A-scan acquired with Cirrus™ HD-OCT centered on the ONH.

Main Outcome Measures

ONH topographic parameters, peripapillary RNFL thickness, and the area under receiver operating characteristic curves (AUCs).

Results

For distinguishing normal from glaucomatous eyes, regardless of disease stage, the six best parameters (expressed as AUC) were vertical rim thickness (VRT, 0.963), rim area (RA, 0.962), RNFL thickness at clock-hour 7 (0.957), RNFL thickness of the inferior quadrant (0.953), vertical cup-to-disc ratio (VCDR, 0.951) and average RNFL thickness (0.950). The AUC for distinguishing between normal and eyes with mild glaucoma was greatest for RNFL thickness of clock-hour 7 (0.918), VRT (0.914), RA (0.912), RNFL thickness of inferior quadrant (0.895), average RNFL thickness (0.893) and VCDR (0.890). There were no statistically significant differences between AUCs for the best ONH parameters and RNFL thickness measurements (p > 0.05).

Conclusions

Cirrus™ HD-OCT ONH parameters are able to discriminate between eyes that are normal from those with glaucoma or even mild glaucoma. There is no difference in the ability of ONH parameters and RNFL thickness measurement, as measured with Cirrus™ OCT, to distinguish between normal and glaucomatous eyes.

Purpose

To determine peripapillary retinal nerve fiber layer (RNFL) thickness values by three-dimensional optical coherence tomography (3D-OCT) in a normal Iranian population and to evaluate the concordance of these measurements with those obtained by the second generation of optical coherence tomography (OCT II).

Methods

In a cross-sectional observational study, 96 normal Iranian subjects 20-53 years old were enrolled. Peripapillary RNFL thickness in one randomly selected eye of each subject was measured by 3D-OCT and also by OCT II. Standard achromatic perimetry, corneal pachymetry and A-scan ultrasonographic biometry were also performed. Other study variables included age, gender, laterality (right versus left eye), refractive error, corneal diameter and disc area.

Results

Mean peripapillary RNFL thickness measured by 3D-OCT (75.50±8.38) μm was significantly less than that measured by OCT II (144.10±33.32 μm) (P<0.001). Using 3DOCT, no significant difference in peripapillary RNFL thickness was observed by gender (P=0.90) or laterality (P=0.17); RNFL thickness had no correlation with age (P=0.95), axial length (P=0.32), spherical equivalent refractive error (P=0.21), central corneal thickness (P=0.66) and disc area (P=0.31). However, a positive correlation was found between peripapillary RNFL thickness and corneal diameter (P=0.03).

Conclusion

3D-OCT seems to yield lower RNFL thickness values as compared to OCT II. It seems advisable to obtain separate baseline measurements when using different generations of OCT machines.

Purpose

To measure choroidal thickness and to determine parameters associated with it.

Design

Cross-sectional study.

Participants

Seventy-four glaucoma patients and glaucoma suspects.

Methods

Spectral domain optical coherence tomography (SDOCT) scans were obtained to estimate average choroidal thickness in a group of glaucoma suspects and glaucoma patients. Average thickness was calculated from enhanced depth SDOCT images and manually analyzed with Image J software. Open angle glaucoma, open angle glaucoma suspect, primary angle closure glaucoma, primary angle closure, and primary angle closure suspect were defined by published criteria. Glaucoma suspects had normal visual fields bilaterally. Glaucoma was defined by specific criteria for optic disc damage and visual field loss in at least one eye. The most affected eye was analyzed for comparisons across individuals, while right/left and upper half/lower half comparisons were made to compare thickness against degree of visual field damage.

Main Outcome Measured

Average macular and peripapillary choroidal thickness measured using SDOCT.

Results

The choroidal-scleral interface (CSI) was visualized in 86% and 96% of the macular and peripapillary scans, respectively. In multivariable linear regression analysis, the macular choroid was significantly thinner in association with 4 features: longer eyes (22 µm per mm longer [95% confidence Interval (CI): −33, −11]), older individuals (31 µm thinner per decade older [95% CI: −44 −17]), lower diastolic ocular perfusion pressure (26 µm thinner per 10 mmHg lower [95% CI: 8, 44]), and thicker central corneas (6 µm per 10 µm thicker cornea [95% CI: −10, 0]). The choroid was not significantly thinner in glaucoma patients than in suspects (14 µm [95% CI: −54, 26], p=0.5). Peripapillary choroidal thickness was not significantly different between glaucomaand suspect patients. Thickness was not associated with damage severity as estimated by visual field mean deviation or nerve fiber layer thickness, including comparisons of right to left eye or upper to lower values.

Conclusion

Age, axial length, central corneal thickness, and diastolic ocular perfusion pressure are significantly associated with choroidal thickness in glaucoma suspects and glaucoma patients. Degree of glaucoma damage was not consistently associated with choroidal thickness.

Aims

To evaluate, with fundus perimetry, the peripapillary differential light threshold (DLT) in eyes with glaucoma and ocular hypertension (OHT), and compare it with peripapillary retinal nerve fibre layer (RNFL) thickness.

Methods

35 glaucomatous, 29 OHT and 24 control eyes were included. Peripapillary DLT at 1° from the optic nerve head was quantified with fundus perimetry; peripapillary RNFL thickness was measured over the same area by optical coherence tomography.

Results

Mean (SD) peripapillary DLT was 19.2 (1.7), 17.6 (4.2) and 10.1 (6.9) dB in control, OHT and glaucomatous eyes, respectively (p<0.001). Mean (SD) RNFL thickness was 98.4 (35.3), 83.9 (35.1) and 55.8 (28.2) μm, respectively (p<0.001). Mean peripapillary DLT showed higher sensitivity and specificity in differentiating the three groups compared with RNFL thickness.

Conclusion

Progressive, significant reduction of peripapillary DLT was documented in OHT and glaucomatous eyes compared with controls (p<0.001). DLT reduction parallels RNFL reduction.

Purpose.

To develop an automated method for the quantification of volumetric optic disc swelling in papilledema subjects using spectral-domain optical coherence tomography (SD-OCT) and to determine the extent that such volumetric measurements correlate with Frisén scale grades (from fundus photographs) and two-dimensional (2-D) peripapillary retinal nerve fiber layer (RNFL) and total retinal (TR) thickness measurements from SD-OCT.

Methods.

A custom image-analysis algorithm was developed to obtain peripapillary circular RNFL thickness, TR thickness, and TR volume measurements from SD-OCT volumes of subjects with papilledema. In addition, peripapillary RNFL thickness measures from the commercially available Zeiss SD-OCT machine were obtained. Expert Frisén scale grades were independently obtained from corresponding fundus photographs.

Results.

In 71 SD-OCT scans, the mean (± standard deviation) resulting TR volumes for Frisén scale 0 to scale 4 were 11.36 ± 0.56, 12.53 ± 1.21, 14.42 ± 2.11, 17.48 ± 2.63, and 21.81 ± 3.16 mm3, respectively. The Spearman's rank correlation coefficient was 0.737. Using 55 eyes with valid Zeiss RNFL measurements, Pearson's correlation coefficient (r) between the TR volume and the custom algorithm's TR thickness, the custom algorithm's RNFL thickness, and Zeiss' RNFL thickness was 0.980, 0.929, and 0.946, respectively. Between Zeiss' RNFL and the custom algorithm's RNFL, and the study's TR thickness, r was 0.901 and 0.961, respectively.

Conclusions.

Volumetric measurements of the degree of disc swelling in subjects with papilledema can be obtained from SD-OCT volumes, with the mean volume appearing to be roughly linearly related to the Frisén scale grade. Using such an approach can provide a more continuous, objective, and robust means for assessing the degree of disc swelling compared with presently available approaches.

Volumetric optic disc swelling is quantified using a custom image-analysis algorithm from subjects with papilledema. The resulting mean volumes are roughly linearly related to corresponding expert-defined Frisén scale grades.

Purpose

To assess the impact of axial length on the age-related peripapillary retinal nerve fiber layer (RNFL) thinning.

Methods

This cross-sectional observational comparative case series included 172 eyes from 172 healthy Korean subjects. Peripapillary RNFL thickness was measured using an Optic Disc Cube 200 × 200 scan of spectral domain Cirrus HD OCT and the axial length was measured using IOL Master Advanced Technology. In age groups based on decade, the normal ranges of peripapillary RNFL thickness for average, quadrant, and clock-hour sectors were determined with 95% confidence intervals. After dividing the eyes into two groups according to axial length (cut-off, 24.50 mm), the degrees of age-related RNFL thinning were compared.

Results

Among the eyes included in the study, 53 (30.81%) were considered to be long eyes (axial length, 25.04 ± 0.48 µm) and 119 (69.19%) were short-to-normal length eyes (axial length, 23.57 ± 0.60 µm). The decrease in average RNFL thickness with age was less in long eyes (negative slope, -0.12 µm/yr) than in short-to-normal length eyes (negative slope, -0.32 µm/yr) (p < 0.001).

Conclusions

Age-related thinning of peripapillary RNFL thickness is attenuated in long eyes compared to short-to-normal length eyes.

PURPOSE

To evaluate peripapillary retinalnerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography (SD-OCT) in patients with autosomal recessive cone-rod dystrophy (CRD).

DESIGN

Cross-sectional study.

METHODS

Eleven patients (22 eyes) with CRD were studied, including 4 patients with identified ABCA4 gene mutations. Peripapillary RNFL thickness was measured in 16 segments from 4 quadrants. The analyses were based on age- and disc size-adjusted normative data. An abnormal thinning was considered when RNFL thickness measurements were under the 5th percentile in at least 2 out of 4 segments in a quadrant. Mean RNFL thickness was quantitatively compared to normative data obtained from 134 subjects.

RESULTS

Eight patients (73%) had peripapillary RNFL thinning in at least one quadrant of at least one eye, including 3 out of 4 patients with known ABCA4 gene mutations. Peripapillary RNFL thinning in the temporal quadrant was most commonly seen in 11 (79%) of 14 eyes with thinning in at least one quadrant. Significant thinning of the overall peripapillary RNFL was observed in CRD patients compared to that of controls (p=0.0002). Subgroup analysis showed that 8 (89%) of 9 patients who were older than 40 years had thinning in at least one quadrant of at least one eye.

CONCLUSIONS

Peripapillary RNFL thinning was commonly observed in our patients with autosomal recessive CRD. The results confirm that the inner retinal structures can be affected in outer retinal disease. Careful evaluation of the inner retina may be important in determining the success rate of potential treatments for predominantly outer retinal diseases.

AIM—Quantification of haemodynamics of the peripapillary choroid in and the assessment of possible differences between normal subjects (N), ocular hypertensive (OHT), primary open angle (POAG), and normal pressure glaucoma (NPG) patients.
METHODS—Video fluorescein angiograms (Rodenstock SLO 101) were made in 22 N subjects, 12 OHT, 48 POAG, and 46 NPG patients. The angiographically derived dye build up curves were described by means of an exponential model. One of the model parameters is the time constant τ theoretically reflecting local blood refreshment time; the blood refreshment time τ is the time needed to replace the blood volume in the choriocapillaris, inversely proportional to the local choroidal blood flow. Other variables are maximal fluorescence (Fdt) and time of first fluorescence (t0). Mean variable values were calculated for disc area and circular areas around the disc.
RESULTS—Fdt of the disc was significantly lower in the POAG and NPG patients. There was no statistical difference in t0 between the study groups. The choroidal blood refreshment time was significantly longer in NPG patients and to a lesser extent in the POAG patients compared with the normal controls. The slowest choroidal blood refreshment can be found in the NPG group. The median choroidal blood refreshment times (25th-75th percentile) in the controls, OHT, POAG, and NPG patients were 4.1 (3.7-4.5), 4.4 (3.7-6.4), 5.8 (4.3-6.8), and 7.1 (5.5-9.3) seconds respectively.
CONCLUSIONS—With the help of parametrisation of dye curves, using a one compartmental model, choroidal haemodynamics can be quantified. The blood refreshment time of the peripapillary choriocapillaris was found to be significantly prolonged especially in NPG patients; this may indicate slower choroidal haemodynamics in NPG patients.



BACKGROUND AND OBJECTIVE

Optical coherence tomography (OCT) is able to determine the optic disc margin automatically. The aim of this study was to investigate the accuracy of the automatic OCT optic nerve head measurements in the presence of peripapillary atrophy.

PATIENTS AND METHODS

This was a cross-sectional, retrospective study. Thirty-one subjects with peripapillary atrophy underwent optic nerve head scanning with OCT version 3. Nineteen of the eyes were classified clinically as having glaucoma, nine had suspected glaucoma, and three were normal. Automatic OCT results were compared with manual tracing results.

RESULTS

Significant differences were found between most OCT optic nerve head automated and manual disc assessment parameters; however, good agreement was found between the two methods for all parameters (intraclass correlation, 0.71 to 0.94). Areas under receiver operator characteristics curves for clinical status were similar for all parameters with both methods.

CONCLUSION

Automated OCT optic nerve head analysis may be used in the clinical setting in the presence of peripapillary atrophy; however, caution should be used when comparing individual results with population-derived optic nerve head results.

Purpose:

To evaluate the ability of spectral domain optical coherence tomography (OCT) peripapillary retinal nerve fiber layer thickness (RNFLT) parameters to distinguish normal eyes from those with early glaucoma in Asian Indian eyes.

Design:

Observational cross-sectional study.

Materials and Methods:

One hundred and seventy eight eyes (83 glaucoma patients and 95 age matched healthy subjects) of subjects more than 40 years of age were included in the study. All subjects underwent RNFLT measurement with spectral OCT/ scanning laser ophthalmoscope (SLO) after dilatation. Sensitivity, specificity and area under the receiving operating characteristic curve (AROC) were calculated for various OCT peripapillary RNFL parameters.

Results:

The mean RNFLT in healthy subjects and patients with early glaucoma were 105.7 ± 5.1 μm and 90.7 ± 7.5 μm, respectively. The largest AROC was found for 12 o’clock- hour (0.98), average (0.96) and superior quadrant RNFLT (0.9). When target specificity was set at ≥ 90% and ≥ 80%, the parameters with highest sensitivity were 12 o’clock -hour (91.6%), average RNFLT (85.3%) and 12 o’ clock- hour (96.8 %), average RNFLT (94.7%) respectively.

Conclusion:

Our study showed good ability of spectral OCT/ SLO to differentiate normal eyes from patients with early glaucoma and hence it may serve as an useful adjunct for early diagnosis of glaucoma.

Purpose

To evaluate the relationship between optic disc and retinal nerve fiber layer (RNFL) measurements obtained with the optical coherence tomography (OCT) and the Heidelberg retina topography (HRT) in normal, normal tension glaucoma (NTG), and high tension glaucoma (HTG).

Methods

Normal, NTG and HTG subjects who met inclusion and exclusion criteria were evaluated retrospectively. One hundred seventy eyes of 170 patients (30 normal, 40 NTG, and 100 HTG) were enrolled. Complete ophthalmologic examination, HRT, OCT, and automated perimetry were evaluated.

Results

Disc area, cup area and cup/disc area ratio measured with HRT were significantly different between NTG and HTG (all p<0.05). Mean RNFL thickness measured by OCT with ascanning diameter of 3.4 mm was larger in NTG than HTG (84.97±24.20 µm vs. 73.53±27.17 µm, p=0.037). Four quadrant RNFL thickness measurements were not significantly different between NTG and HTG (all p>0.05). Mean deviation and corrected pattern standard deviation measured by automated perimetry was significantly correlated with mean and inferior RNFL thickness in both NTG and HTG (Pearson's r, p<0.05). Mean RNFL thickness/disc area ratio was significantly larger in HTG than NTG (35.21±18.92 vs. 31.30±10.91, p=0.004).

Conclusions

These findings suggest that optic disc and RNFL damage pattern in NTG may be different from those of HTG.

Purpose

To compare the diagnostic abilities of peripapillary retinal nerve fiber layer (RNFL) and macular inner retina (MIR) measurements by spectral domain optical coherence tomography (SD–OCT) in Indian eyes early glaucoma.

Methods

In an observational, cross-sectional study, 125 eyes of 64 normal subjects and 91 eyes of 59 early glaucoma patients underwent RNFL and MIR imaging with SD–OCT. Glaucomatous eyes had characteristic optic nerve and RNFL abnormalities and correlating visual field defects and a mean deviation of better than or equal to -6 dB on standard automated perimetry. Areas under the receiver operating characteristic curves (AUC), sensitivities at a fixed specificity and likelihood ratios (LRs) were estimated for all RNFL and MIR parameters.

Results

The AUCs for the RNFL parameters ranged from 0.537 for the temporal quadrant thickness to 0.821 for the inferior quadrant RNFL thickness. AUCs for the MIR parameters ranged from 0.603 for the superior minus inferior MIR thickness average to 0.908 for ganglion cell complex focal loss volume (GCC–FLV). AUC for the best MIR parameter (GCC–FLV) was significantly better (P<0.001) than that of the best RNFL parameter (inferior quadrant thickness). The sensitivities of these parameters at high specificity of 95%, however, were comparable (52.7% vs58.2%). Evaluation of the LRs showed that outside normal limits results of most of the RNFL and MIR parameters were associated with large effects on the post-test probability of disease.

Conclusion

MIR parameters with RTVue SD–OCT were as good as the RNFL parameters to detect early glaucoma.

We evaluated the relationship between the size of the peripapillary crescent and the axial length (AL) of the eye as well as the fine structure of the peripapillary crescent in selected eyes. Infrared fundus imaging and spectral domain optical coherence tomography (SDOCT) (Spectralis HRA+OCT, Heidelberg Engineering, Germany) centered at the fovea were performed on 72 healthy adults. On the infrared fundus images, we measured (a) the distance between the foveola and the temporal edge of the optic disc (FOD) and (b) the distance between the foveola and the temporal edge of the peripapillary crescent (FOC) (if present). A peripapillary crescent presented at the nasal margin of the disc in 64% of the subjects. The FOD and FOC were 4.22mm±0.46 and 3.97mm±0.25, respectively. Only the FOD was significantly correlated with axial length. As AL increased by 10%, the FOD increased by 13%, the outer neural retina only expanded by 4% (as indicated by the FOC). This result emphasizes that retinal stretching may not mirror scleral growth, and the existence in some eyes of a difference between the photoreceptor margin and RPE margin suggests that within the retina there could be slippage during eye growth.

AIMS—To determine if normal tension glaucoma (NTG) patients differ from age matched controls in blood flow to the peripapillary retina, as measured with confocal scanning laser Doppler flowmetry (cSLDF; "Heidelberg retinal flowmetry").
METHODS—12 NTG patients and 12 age matched controls were compared using (a) 10 × 10 pixel boxes (the instrument default sample size), taken from the nasal and temporal peripapillary retina, (b) the average from two of these boxes, and (c) every qualifying pixel within the peripapillary retina.
RESULTS—Patients and controls did not differ in blood flow measured using the default sample from a single 10 × 10 pixel box, placed in either the temporal or nasal peripapillary retina, or expressed as the average from these two boxes. However, in histograms using every pixel from the peripapillary retina, NTG patients displayed significantly higher percentages of minimal flow pixels (defined as less than one arbitrary unit of flow: 30% v 19%, p <0.01), and significantly lower flow in the 25th, 50th, and 75th percentile flow pixel (each p <0.05) than did age matched controls.
CONCLUSION—NTG is characterised by reduced blood flow in the peripapillary retina, a result suggesting that blood flow deficits accompany, and perhaps may contribute to, disease development in these patients.

 Keywords: glaucoma; retina; blood flow; laser Doppler flowmeter

Aim

To evaluate the influence of optic disc size on the diagnostic accuracy of macular ganglion cell complex (GCC) and conventional peripapillary retinal nerve fiber layer (pRNFL) analyses provided by spectral domain optical coherence tomography (SD-OCT) in glaucoma.

Methods

Eighty-two glaucoma patients and 30 healthy subjects were included. All patients underwent GCC (7 × 7 mm macular grid, consisting of RNFL, ganglion cell and inner plexiform layers) and pRNFL thickness measurement (3.45 mm circular scan) by SD-OCT. One eye was randomly selected for analysis. Initially, receiver operating characteristic (ROC) curves were generated for different GCC and pRNFL parameters. The effect of disc area on the diagnostic accuracy of these parameters was evaluated using a logistic ROC regression model. Subsequently, 1.5, 2.0, and 2.5 mm2 disc sizes were arbitrarily chosen (based on data distribution) and the predicted areas under the ROC curves (AUCs) and sensitivities were compared at fixed specificities for each.

Results

Average mean deviation index for glaucomatous eyes was −5.3 ± 5.2 dB. Similar AUCs were found for the best pRNFL (average thickness = 0.872) and GCC parameters (average thickness = 0.824; P = 0.19). The coefficient representing disc area in the ROC regression model was not statistically significant for average pRNFL thickness (−0.176) or average GCC thickness (0.088; P ≥ 0.56). AUCs for fixed disc areas (1.5, 2.0, and 2.5 mm2) were 0.904, 0.891, and 0.875 for average pRNFL thickness and 0.834, 0.842, and 0.851 for average GCC thickness, respectively. The highest sensitivities – at 80% specificity for average pRNFL (84.5%) and GCC thicknesses (74.5%) – were found with disc sizes fixed at 1.5 mm2 and 2.5 mm2.

Conclusion

Diagnostic accuracy was similar between pRNFL and GCC thickness parameters. Although not statistically significant, there was a trend for a better diagnostic accuracy of pRNFL thickness measurement in cases of smaller discs. For GCC analysis, an inverse effect was observed.

Purpose

To determine the effects of age, optic disc area, ethnicity, eye, gender, and axial length on the retinal nerve fiber layer (RNFL) in the normal human eye as measured by Stratus OCT (optical coherence tomography).

Design

Cross-sectional observational study.

Participants

Three hundred twenty-eight normal subjects 18 to 85 years old.

Methods

Peripapillary Fast RNFL scans performed by Stratus OCT with a nominal diameter of 3.46 mm centered on the optic disc were performed on one randomly selected eye of each subject.

Main Outcome Measures

Linear regression analysis of the effects of age, ethnicity, gender, eye, axial length, and optic disc area on peripapillary RNFL thickness.

Results

The mean RNFL thickness for the entire population was 100.1 μm (standard deviation, 11.6). Thinner RNFL measurements were associated with older age (P<0.001); being Caucasian, versus being either Hispanic or Asian (P = 0.006); greater axial length (P<0.001); or smaller optic disc area (P = 0.010). For every decade of increased age, mean RNFL thickness measured thinner by approximately 2.0 μm (95% confidence interval [CI], 1.2–2.8). For every 1-mm-greater axial length, mean RNFL thickness measured thinner by approximately 2.2 μm (95% CI, 1.1–3.4). For every increase in square millimeter of optic disc area, mean RNFL thickness increased by approximately 3.3 μm (95% CI, 0.6–5.6). Comparisons between ethnic groups revealed that Caucasians had mean RNFL values (98.1±10.9 μm) slightly thinner than those of Hispanics (103.7±11.6 μm; P = 0.022) or Asians (105.8±9.2 μm; P = 0.043). There was no relationship between RNFL thickness and eye or gender.

Conclusions

Retinal nerve fiber layer thickness, as measured by Stratus OCT, varies significantly with age, ethnicity, axial length, and optic disc area. These variables may need to be taken into account when evaluating patients for diagnosis and follow-up of glaucoma, particularly at the lower boundary of the normal range. Due to the relatively small numbers of subjects of Asian and African descent in the normative database, conclusions regarding the effect of ethnicity should be interpreted with caution.

BACKGROUND AND OBJECTIVE

To correlate peripapillary retinal nerve fiber layer (NFL) loss and visual field defects in nonarteritic ischemic optic neuropathy (NAION).

PATIENTS AND METHODS

Patients with NAION and control subjects were enrolled in a case-control study. Participants were scanned with a Fourier domain optical coherence tomography (OCT) system. Peripapillary NFL thickness was averaged in hemispheric, quadrant, and octant divisions. Standard achromatic static perimetry was used to assess visual fields.

RESULTS

The reproducibility of peripapillary NFL parameters was excellent in both the healthy and NAION groups. Eyes in the NAION group showed a significant decrease of peripapillary NFL thickness in terms of the overall average, all quadrant averages, and all octants. There were statistically significant correlations between the peripapillary NFL and visual fields in terms of both overall averages and superior-inferior differences.

CONCLUSION

In NAION, the visual field and peripapillary NFL losses are correlated in both severity and location. Fourier domain OCT provides reproducible measurement of the peripapillary NFL and may be useful in the assessment of NAION.

AIMS—To determine whether any differences may exist in the relation between the neural capacity as determined by high pass resolution perimetry and the thickness of the retinal nerve fibre layer (RNFL) in patients having normal tension glaucoma (NTG) with a relatively high intraocular pressure (IOP) between 16 and 21 mm Hg (HNTG) v those with a lower IOP below 15 mm Hg (LNTG).
METHODS—Scanning laser polarimetry and high pass resolution perimetry were performed in 20 eyes of 20 patients with HNTG and 21 eyes of 21 patients with LNTG. The correlation between total and regional thickness of the peripapillary RNFL and the corresponding total and regional neural capacity with linear regression analysis were evaluated.
RESULTS—Overall, although the total RNFL thickness was not significantly correlated with the total neural capacity, the RNFL thickness in each of the superior and inferior quadrants was significantly correlated with the corresponding regional neural capacity (r=0.44, p=0.0045; r=0.39, p=0.0126 for each). The RNFL thickness in each of the superior and inferior quadrants in the HNTG group was significantly correlated with the corresponding regional neural capacity (r=0.52, p=0.0196; r=0.49, p=0.0286 for each). No significant correlation between neural capacity and the RNFL thickness was observed either globally or regionally in the LNTG group.
CONCLUSION—The degree of the correlation between neural capacity as determined by high pass resolution perimetry and thickness of the RNFL as measured by scanning laser polarimetry appeared to differ in NTG patients with an IOP higher than 15 mm Hg v those with a lower IOP.

 Keywords: scanning laser polarimetry; high pass resolution perimetry; normal tension glaucoma

Background

The purpose of this study was to investigate the correlations between microcirculation in the optic disc, average peripapillary retinal nerve fiber layer thickness cupping parameters, and visual field defects in glaucoma patients with the generalized enlargement disc type.

Methods

A total of 38 eyes from 38 glaucoma patients with the generalized enlargement disc type were included. The microcirculation of the optic nerve head was examined with laser speckle flow graphy, and the mean blur rate in all areas, in vessel area, and in tissue area were calculated using the laser speckle flow graphy analyzer software. Average peripapillary retinal nerve fiber layer thickness was measured using Stratus optical coherence tomography, and cupping parameters were accessed using the Heidelberg retina tomograph. The mean deviation in the Humphrey field analyzer (30-2 SITA standard) was analyzed. The correlation between these parameters was evaluated using the Spearman rank correlation coefficient.

Results

The correlation coefficient of mean blur rate in all optic disc area to the average peripapillary retinal nerve fiber layer thickness, vertical C/D, and mean deviation were r = 0.7546 (P < 0.0001), r = −0.6208 (P < 0.0001), and r = 0.6010 (P = 0.0001), respectively. The mean blur rate in tissue area of the optic disc showed r = 0.7305 (P < 0.0001), r = −0.6438 (P < 0.0001), and r = 0.6338 (P < 0.0001).

Conclusion

We found that the mean blur rate in the optic disc was significantly correlated with the average peripapillary retinal nerve fiber layer thickness, vertical C/D, and mean deviation in patients with the generalized enlargement disc type of glaucoma. In particular, the mean blur rate in tissue area was more highly correlated than the vessel area with other results of examination in glaucoma patients with the generalized enlargement disc type.