Faculty Bibliography

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 pulsatile ocular blood flow (POBF) analysis in normal subjects and glaucoma patients by comparison of POBF measurements with functional (as determined by visual field [VF]) and structural (as determined by optical coherence tomography [OCT]) measures. DESIGN: Prospective, cross-sectional study. METHODS: Forty-one eyes of 24 consecutive glaucoma patients and 20 eyes of 10 healthy subjects were studied; POBF analysis was performed on all subjects at the same visit as VF testing and OCT retinal nerve fiber layer (NFL) thickness measurement. The mean results of normal and glaucomatous eyes were compared for each method. Correlation between measurements obtained with each modality and the discriminating power using receiver operator characteristic curves was tested. RESULTS: The mean POBF (standard deviation [SD]) in the normal group was 1,010.4 (292.8) microl/min and 989.3 (305.5) microl/min in the glaucoma group (P =.90). Significant differences between groups were found for VF mean deviation and pattern standard deviation (P =.02, P =.004, respectively) and OCT mean NFL thickness (P <.0001). No correlation was found between POBF parameters and intraocular pressure, VF, or OCT variables except for intraocular pressure in glaucoma group (r = -.43, P =.003). The area under the receiver operator characteristic curves was higher for VF indexes and OCT mean NFL thickness than POBF parameters for distinguishing between normal and glaucomatous eyes. CONCLUSIONS: The wide range of normal values and the low discriminating power of POBF between normal and glaucomatous eyes limits the clinical use of the device for glaucoma patients.

PURPOSE: To assess changes in retinal nerve fiber layer (NFL) thickness in glaucoma patients after filtration surgery by using optical coherence tomography (OCT). DESIGN: Retrospective observational case series. PARTICIPANTS: Thirty-eight eyes of 31 glaucoma patients who underwent trabeculectomy or a combined procedure of cataract extraction and trabeculectomy were evaluated retrospectively. METHODS: Eyes were imaged with OCT before surgery (1 week to 6 months before surgery; mean +/- standard deviation [SD], 71.3 +/- 61.2 days) and after surgery (6-12 months after surgery; 247.2 +/- 63.5 days) to measure peripapillary NFL thickness. MAIN OUTCOME MEASURES: Changes in mean and segmental NFL thickness with respect to age, postoperative change in intraocular pressure (IOP), preoperative visual field test global indices, and change in visual field global indices. RESULTS: A significant increase in the overall mean NFL thickness was present after surgery (P < 0.0001). Segmental analysis found a significant increase in NFL thickness in the nasal, superior, and temporal quadrants. IOP decreased after surgery from 22.0 +/- 6.4 mmHg to 11.4 +/- 4.7 mmHg (mean +/- SD). Twenty-eight (73.7%) of 38 eyes had an IOP reduction >30%. The mean NFL thickness increase (0.5- microm/mmHg decrease of IOP) was significantly correlated with the IOP reduction (r = -0.41; P = 0.03). No correlation was found between NFL thickness changes and age, preoperative visual field global indices, or change in visual field global indices. CONCLUSIONS: A significant increase of the mean NFL thickness, which was related to IOP reduction, was detected after glaucoma filtration surgery.

PURPOSE: To compare computer-assisted planimetry using the Discam system (Marcher Enterprises Ltd., Hereford, UK), confocal scanning laser ophthalmoscopy (CSLO), and stereoscopic disc photography with respect to optic nerve head (ONH) measurements and glaucoma status. DESIGN: Comparative, observational case series and interobserver variability study. METHODS: Three hundred eighty-six eyes of 233 consecutive subjects were imaged with the Discam, and a subset underwent ONH evaluation with CSLO (n = 297), stereoscopic photography (n = 233), or both. Subjects were classified into normal, glaucoma suspect, and glaucoma groups based on clinical findings of slit-lamp disc examination and visual field testing. Agreement of cup-to-disc ratio measurements among the three technologies was assessed by the intraclass correlation coefficient (ICC) and areas under the receiver operator characteristic (AROC) curves. MAIN OUTCOME MEASURES: Cup-to-disc ratio as measured by Discam, CSLO, and stereography. RESULTS: Intraclass correlation coefficients calculated using the two-way random effects model for comparing Discam, CSLO, and stereography among cup-to-disc area ratio, vertical cup-to-disc ratio, and horizontal cup-to-disc ratio were 0.46 to 0.53. The ICC was higher for eyes with larger optic discs (0.51) than those with smaller ones (0.32). The ICC calculated using the fixed effects model for the Discam and CSLO comparison was 0.72. Areas under the receiver operator characteristic curves were 0.67 to 0.80 among the three technologies comparing normal with glaucomatous eyes. In general, there was no statistically significant difference between techniques with respect to sensitivity and specificity of glaucoma detection. CONCLUSIONS: There is good agreement between ONH measurements obtained by Discam, CSLO, and stereography; however, the results are not interchangeable. Similar AROC curve values among all three techniques imply that the Discam, CSLO, and stereography perform equally for the determination of glaucoma status.

PURPOSE: To evaluate the relationship between optic nerve head (ONH) measurements generated by optical coherence tomography (OCT; versions 2 and 3) and confocal scanning laser ophthalmoscopy (CSLO) and to compare the association between OCT and CSLO ONH measurements with glaucoma disease status, as determined by clinical evaluation and perimetry. DESIGN: Cross-sectional study. METHODS: In a prospective study in the glaucoma service of an academic department of ophthalmology, 159 eyes (97 subjects) and 77 eyes (44 subjects) were recruited in two separate periods. All subjects were scanned with a CSLO device. Subjects tested within the first period of recruitment were scanned with OCT version 2 and in the second period with OCT version 3. The main outcome measure was the correlation between automatic and manually defined OCT ONH measurements and the correlation of CSLO and OCT ONH measurements between devices and with glaucoma disease status. RESULTS: A high correlation was found between ONH measurements obtained by the automatic determination of ONH margin and those obtained by manual tracing of the disk margin (r =.93 to.98). Optical coherence tomography and CSLO ONH measurements were highly correlated. Optical coherence tomography-measured mean disk area was significantly larger than that measured by CSLO, as were all other disk size-related parameters. The areas under the receiver operator characteristic (AROC) curves for the associations between CSLO and OCT ONH measurements and clinical diagnosis were found to be similar and in the range of 0.47 to 0.79 for both devices. CONCLUSIONS: Automated OCT ONH measurements correlate highly with those obtained by manual tracing of disk margin. Optical coherence tomography and CSLO ONH analyses are highly correlated and have similar associations with glaucoma disease status.

PURPOSE: To evaluate the hypothesis that macular thickness correlates with the diagnosis of glaucoma. DESIGN: Cross-sectional study. PARTICIPANTS: We studied 367 subjects (534 eyes), including 166 eyes of 109 normal subjects, 83 eyes of 58 glaucoma suspects, 196 eyes of 132 early glaucoma patients, and 89 eyes of 68 advanced glaucoma patients. METHODS: We used optical coherence tomography (OCT) to measure macular and nerve fiber layer (NFL) thickness and to analyze their correlation with each other and with glaucoma status. We used both the commercial and prototype OCT units and evaluated correspondence between measurements performed on the same eyes on the same days. MAIN OUTCOME MEASURE: Macular and NFL thickness as measured by OCT. RESULTS: All NFL parameters both in prototype and commercial OCT units were statistically significantly different comparing normal subjects and either early or advanced glaucoma (P < 0.001). Inner ring, outer ring, and mean macular thickness both in prototype and commercial OCT devices were found to be significantly different between normal subjects and advanced glaucomatous eyes (P < 0.001). The outer ring was the only macular parameter that could significantly differentiate between normal and early glaucoma with either the prototype or commercial OCT unit (P = 0.003, P = 0.008, respectively). The area under the receiver operator characteristic (AROC) curves comparing mean NFL thickness between normal and advanced glaucomatous eyes was 1.00 for both the prototype and commercial OCT devices for eyes scanned on both machines on the same day. The AROC comparing mean macular thickness in normal and advanced glaucomatous eyes scanned on both machines on the same day was 0.88 for the prototype OCT device and 0.80 for the commercial OCT. CONCLUSIONS: Both macular and NFL thickness as measured by OCT showed statistically significant correlations with glaucoma, although NFL thickness showed a stronger association than macular thickness. There was good correspondence between findings using both the prototype and commercial OCT units. Macular and NFL thickness measurements made with OCT may have usefulness in the clinical assessment of glaucoma.