Specific Location of Disc Hemorrhage is Linked to Nerve Fiber Layer Defects.

PURPOSE: To investigate the relationship between retinal nerve fiber layer (RNFL) defects and the quadrant and proximal location of disc hemorrhages (DHs) in a large population examined for health screening. METHODS: A total of 168,044 subjects older than 20 years underwent a single screening ophthalmic examination with color fundus photography as part of a comprehensive health screening program. The presence and location of DHs and RNFL defects were assessed. The DH locations were defined according to the quadrant location (inferotemporal, superotemporal, inferonasal, or superonasal) and the most proximal end of DHs relative to the disc center (cup base, cup margin, disc rim, or extrapapillary region). Using these two location descriptors as independent variables, a logistic regression analysis was conducted to explore the effects of DH location on RNFL defects. RESULTS: Two hundred twenty-six eyes had DH and 120 (53.1%) of them had RNFL defects. After adjusting for proximal location, DHs located in the inferotemporal quadrant accompanied RFNL defects 12 times more frequently than those in the superonasal quadrant (odds ratio [OR], 11.81; P = .004). Conversely, after adjusting for quadrant location, the ORs for an associated RNFL defect were 3.73 (P < .001), 16.54 (P < .001), and 8.91 (P = .002) for DHs with the proximal end at the disc rim, cup margin, and cup base, respectively. CONCLUSIONS: Among the four quadrants and four proximal locations, DHs were identified most frequently in the inferotemporal quadrant and outside the disc, respectively. Some DH locations, such as the inferotemporal quadrant and the cup margin, were associated with RNFL defects, whereas others were not.

Changes in peripapillary retinal nerve fiber layer distribution by axial length.

PURPOSE: To investigate the effect of axial length on the peripapillary retinal nerve fiber layer (RNFL) distribution and the risk of misdiagnosing normal subjects when using the instrument's built-in normative database. METHODS: Healthy young volunteers underwent ophthalmologic examinations including RNFL thickness analysis with spectral-domain optical coherence tomography (OCT), autorefraction, and axial length measurement. The average RNFL thickness values reported along the calculation circle for whole circle, quadrants, and clock hours were recorded and evaluated at the 5% probability level for significant disparities in comparison with the built-in RNFL database. Angular locations with maximal RNFL thickness in the superotemporal and inferotemporal RNFL humps were determined. The relationships of axial length with these variables were analyzed using both linear regression and logistic regression models. RESULTS: A total of 485 eyes of 485 subjects were analyzed. The average 360° RNFL thickness became thinner as the axial length increased (r = -0.244, p < 0.001). As the axial length increased, the average RNFL thicknesses in the 1, 2, 4, 5, 6, and 12-o'clock hour sectors decreased whereas those of the 7, 8, 9, 10, and 11-o'clock hour sectors increased. In addition, as the axial length increased, two major RNFL humps were located more temporally and it became significantly more likely for the 1, 2, 5, 6, and 12-o'clock hour sectors to fall below the p < 0.05 significance limits for normal thickness. CONCLUSIONS: Peripapillary RNFL thickness changes differently in different peripapillary locations as axial length increases. Because long eyes may lead to misleading findings of OCT parameters depending on the peripapillary location, their relationship to the axial length should be considered in the built-in RNFL thickness normative database of OCT.

Differences in the histopathology and matrix metalloproteinase expression in Tenon's tissue of primary open-angle glaucoma and primary angle-closure glaucoma.

PURPOSE: To investigate the differences in the histopathology and matrix metalloproteinase (MMP) expression in the Tenon's tissue of primary open-angle glaucoma (POAG) patients, primary angle-closure glaucoma (PACG) patients, and non-glaucomatous patients. METHODS: POAG and PACG patients, who underwent a trabeculectomy and had no history of ocular disease except glaucoma, were enrolled. The number and instillation period of topical eye drops were reviewed. For the controls, which were patients without glaucoma or a history of ocular surgery, the Tenon's tissue was obtained in the course of retinal detachment surgery. For glaucoma patients, the Tenon's tissue was obtained during the trabeculectomy. H&E and Masson's trichrome staining and immunohistochemistry for MMP-1, MMP-2, and MMP-9 were performed. A total of six eyes of POAG, six eyes of PACG, and four control eyes were evaluated. RESULTS: The duration of topical anti-glaucoma medication and the mean number of anti-glaucoma medications were similar in the POAG and PACG groups. The levels of MMP-1 and 2 were elevated in the POAG and PACG groups compared to the control group (p=0.03, 0.01, respectively). Compared with the control group, the MMP-2 level was higher in the POAG patients (p=0.01), whereas the MMP-1 was higher in the PACG patients (p=0.04). The levels of MMP-9 in the POAG and PACG patients were not significantly different from that of the control patients (p=0.48, 0.26). The levels of MMP-2 were significantly lower in the PACG patients than in the POAG patients (p=0.02). CONCLUSIONS: The MMP expression was altered in the Tenon's tissue of glaucoma patients compared to the control group. The levels of MMP-2 were lower in the PACG patients than in the POAG patients. These results suggest that there may be histopathological differences in the Tenon's tissue of POAG and PACG patients.

Long-term comparison of postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification.

PURPOSE: To compare long-term postoperative refractive outcomes between phacotrabeculectomy and phacoemulsification, both with posterior chamber intraocular lens implantation. SETTING: Department of Ophthalmology, Konyang University, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Seoul, South Korea. DESIGN: Retrospective comparative study. METHODS: Postoperative refractive outcomes were compared between patients with cataract and coexisting primary or secondary open-angle glaucoma (OAG) who had phacotrabeculectomy (combined group) and patients with cataract with or without coexisting OAG who had phacoemulsification alone (phaco-only group). The refractive prediction error, mean absolute error, and median absolute error were compared between groups. Subgroup analysis based on preoperative axial length (AL) was performed (medium >22.0 to <24.5 mm; medium-long ≥24.5 to <26.0 mm; long ≥26.0 mm). RESULTS: The combined group comprised 51 eyes and the phaco-only group, 74 eyes. The mean interval between surgery and refraction measurement was 14.70 months ± 10.80 (SD) (median 13.0 months) and 4.81 ± 4.97 months (median 2.0 months), respectively. Postoperatively, there was no statistically significant between-group difference in the following mean values: refractive prediction error, -0.05 ± 0.64 versus -0.04 ± 0.52 (P = .905); mean absolute error, 0.46 ± 0.44 versus 0.38 ± 0.36 (P = .258); median absolute error, 0.32 (interquartile range [IQR], 0.17, 0.67) versus 0.28 (IQR, 0.13, 0.54) (P = .297). Subgroup analysis also did not show significant differences between the 2 groups (all P > .05). CONCLUSION: The long-term postoperative refractive outcomes of phacotrabeculectomy and phacoemulsification alone were not significantly different in eyes with OAG, regardless of preoperative AL.

Disc hemorrhages in patients with both normal tension glaucoma and branch retinal vein occlusion in different eyes.

PURPOSE: To document the clinical features of disc hemorrhage in patients with branch retinal vein occlusion (BRVO) and normal tension glaucoma (NTG), and to evaluate the relationship between BRVO and NTG with disc hemorrhages. METHODS: From July 2001 to May 2006, sixteen patients with both NTG and BRVO in different eyes were successively collected from outpatient population of Seoul National University Hospital in this observational case series. The frequency and location of disc hemorrhages, history of associated systemic diseases, and the order of the time of diagnosis between NTG and BRVO were studied. RESULTS: All patients had unilateral BRVO, and their mean age was 63.3+/-10.6 years. Disc hemorrhages were detected in eight patients (50%) during the mean follow-up of 26.8 months (range, 3-96 months). Six patients (75%) had disc hemorrhages in the non-BRVO eyes and two patients (25%) in BRVO eyes. Five hemorrhages (62.5%) were located at inferior-temporal quadrant of the optic disc. History of systemic hypertension was identified in 12 patients (75.0%). In 11 patients (68.8%), NTG was diagnosed at the same time as BRVO. CONCLUSIONS: A higher frequency of disc hemorrhages was identified in patients with both BRVO and NTG. Therefore, some cases of NTG, especially with disc hemorrhages, may share a common vascular pathophysiology with BRVO.

Comparison of sensitivities for detecting diffuse and localized retinal nerve fiber layer defects with time-domain optical coherence tomography in patients with glaucoma.

PURPOSE: To compare the ability of time-domain optical coherence tomography (OCT) to detect diffuse and localized retinal nerve fiber layer (RNFL) defects using a built-in normative database in patients with early to moderate glaucoma. METHODS: Subjects with localized visual field defects confined to either hemifield were consecutively recruited. Only 1 eye per subject was considered. Among the 91 eyes with localized RNFL defects, 46 eyes with mean deviations matched to those of the 46 eyes with diffuse RNFL defects were selected for statistical analysis. This case-control study included 46 eyes with diffuse RNFL defects and 46 eyes with localized RNFL defects. The fast RNFL thickness protocol of Stratus OCT was used. The clock-hour and quadrant sector parameters corresponding to the hemifield with the visual field defect were evaluated at P<0.05 with regard to the built-in normative database. The sensitivities of these parameters were compared between diffuse and localized RNFL defects. RESULTS: The sensitivity of the clock-hour sector parameter for diffuse RNFL defects (84.8%) was not significantly different than that for localized RNFL defects (80.4%) (P=0.78). The sensitivity of the quadrant sector parameter for diffuse RNFL defects (74.9%) was significantly higher than that for localized RNFL defects (52.3%) (P=0.04). CONCLUSIONS: The clock-hour parameter of time-domain OCT detected RNFL defects without significant difference in sensitivities between diffuse and localized patterns of RNFL loss in glaucomatous eyes. However, the quadrant parameter of OCT showed better sensitivity for diffuse RNFL defects than for localized RNFL defects.

Short-term effect of standard automated perimetry testing on intraocular pressure in patients with open-angle glaucoma.

Purpose. To evaluate the short-term effect of standard automated perimetry (SAP) testing on intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). Methods. We tested 45 patients (71 eyes) with OAG that had stable IOP under medical treatment. IOP was measured four times using an iCare rebound tonometer (RBT) immediately before, immediately after, 10 minutes after, and 20 minutes after SAP testing. Logistic regression analyses were performed to determine the relationships among SAP test duration, mean deviation of the SAP result, type of glaucoma medications, patient age, and significant IOP change (exceeding 2 mmHg) from baseline IOP. Results. The mean baseline IOP was 13.29 ± 3.06 mmHg. Although IOP changes immediately and 20 minutes after SAP testing were not statistically significant, the IOP change 10 minutes after SAP testing (-0.57 ± 1.84 mmHg) was statistically significant. However, the changes were within the margin of error of the RBT. Test duration, mean deviation, patient age, and type of glaucoma medications did not have a significant influence on IOP change (all P > 0.14). Conclusions. IOP measured by RBT did not vary significantly after SAP testing in patients with OAG. It may be not necessary to reject IOP measured after SAP testing in patients with OAG.

Point-wise relationships between visual field sensitivity and macular thickness determined by spectral-domain optical coherence tomography.

PURPOSE: To evaluate the point-wise relationships between visual field sensitivity (VFS), as measured by standard automated perimetry (SAP), and macular thickness, as determined by spectral-domain optical coherence tomography (SD-OCT), in patients with glaucoma. MATERIALS AND METHODS: One hundred and six glaucoma subjects (one eye per subject) recruited from an academic institution underwent SAP tests (Humphrey field analyzer, central 24-2 of Swedish Interactive Thresholding Algorithm standard) and SD-OCT volume scans (SPECTRALIS, posterior pole asymmetry analysis). The retinal sensitivities of 16 central test points from the SAP results were recorded. Macular thickness values from 4 square cells in an 8 × 8 posterior pole retinal thickness map were averaged for a mean retinal thickness (MRT) value, which corresponded to the 16 central test points in the SAP. In each 16-point area, linear regression analyses of the VFS and the MRT value were performed. RESULTS: The VFS of each 16 central test point showed a significant relationship with the corresponding MRT values (R(2)= 0.133-0.383, all p < 0.001). Central and nasal test points corresponding to an arcuate region revealed a relatively strong correlation in both the superior and inferior hemispheres (R(2)= 0.311-0.383 and 0.288-0.345, respectively), but the superior and inferior-temporal points revealed a relatively weaker correlation (R(2)= 0.149 and 0.133, respectively). CONCLUSIONS: The VFS showed a significant reciprocal relationship with corresponding macular thickness at each test point. However, the level of the relationship varied among different macular sectors, showing the strongest relationship in the arcuate region.

Correct calculation circle location of optical coherence tomography in measuring retinal nerve fiber layer thickness in eyes with myopic tilted discs.

PURPOSE. Retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) can be unreliable in the presence of a myopic tilted disc. The purpose of this study was to investigate the influence of the calculation circle location of spectral domain (SD)-OCT when measuring RNFL thickness in healthy subjects with myopic tilted disc. METHODS. Sixty-nine eyes with myopic tilted disc and no other ocular abnormalities were analyzed. In all eyes, RNFL thickness was measured twice: first, along a calculation circle determined by a built-in algorithm (referred to as circle 1) and then along a manually positioned calculation circle based on the contours of the neural canal opening (NCO) (referred to as circle 2). The mean number of clock hours below normal at the 5% level and the proportion of eyes with abnormally thin clock hours at the 5% level were compared between the two methods: RESULTS. The mean number of clock hours below normal at the 5% level was significantly lower in circle 2 (0.84 ± 1.31) than in circle 1 (1.42 ± 1.43; P < 0.05). The proportion of eyes with abnormally thin clock hours at the 5% level was significantly lower (P < 0.001) in circle 2 (42%) than in circle 1 (69.9%). CONCLUSIONS. In subjects with myopic tilted disc, RNFL thickness measurements along the calculation circle based on the contours of the NCO seem to be more comparable to the normative database of the SD-OCT than does the automatically determined scan position.

Influence of angular width and peripapillary position of localized retinal nerve fiber layer defects on their detection by time-domain optical coherence tomography.

PURPOSE: To investigate the influence of angular width and peripapillary position of localized retinal nerve fiber layer (RNFL) defects on their detection by the time-domain optical coherence tomography (OCT). METHODS: Fast RNFL Stratus OCT scans were obtained from 186 eyes of 186 newly detected glaucoma patients with only a single, localized RNFL defect in either eye. The RNFL defects were divided into subgroups according to their angular width at 15° intervals and superior or inferior position. In the sector average graph of OCT results, abnormal clock-hour sectors were evaluated at P < 5%. RESULTS: Among 154 eyes included in the final data analysis, mean angular width of localized RNFL defects was 21.82 ± 10.38°, and 108 eyes (70.1%) had an inferiorly located RNFL defect. Localized RNFL defects with an angular width interval of 30° to 45° were more frequently detected by Stratus OCT than those with an angular width of <15° (odds ratio = 30.32, P = 0.001). Inferior RNFL defects were not detected more frequently by Stratus OCT than superior RNFL defects (odds ratio = 1.58, P = 0.24). CONCLUSIONS: Only the angular width of localized RNFL defects had a significant influence on the sensitivity of the time-domain OCT.

Comparison of optical coherence tomography and scanning laser polarimetry for detection of localized retinal nerve fiber layer defects.

PURPOSES: To compare the ability of Stratus optical coherence tomography (Stratus OCT) and scanning laser polarimetry with variable corneal compensator (GDx VCC) in recognizing a localized retinal nerve fiber layer (RNFL) defect identified on red-free fundus photography. MATERIALS AND METHODS: Fifty-three patients with only 1 localized RNFL defect in either eye were taken RNFL thickness analysis using Stratus OCT and GDx VCC. Thirty-nine healthy subjects were used as controls and only 1 eye per subject was considered. Using red-free photography as the standard reference test, sensitivity and specificity for photographic defects, and topographic correlation with photographic defects were compared between Stratus OCT (sector average graph) and GDx VCC (deviation from normal map). Abnormal sectors at P<5% compared with their internal normative database were evaluated. RESULTS: After excluding eyes with unacceptable scan images, 38 healthy eyes and 47 glaucomatous eyes were finally included. Stratus OCT and GDx VCC showed moderate sensitivity (78.7%) and high specificity (94.7% and 89.5%, respectively), and there was no significant difference (P=1.00 and P=0.69, respectively). RNFL defects determined by Stratus OCT and GDx VCC were correlated well with photographic RNFL defects in terms of peripapillary localization and clock-hour size, and there was no significant difference between 2 imaging devices (P=0.20 and P=0.27, respectively). CONCLUSIONS: In recognizing a localized RNFL defect, overall diagnostic performance of Stratus OCT and GDx VCC with regard to their internal normative database was not significantly different. As both Stratus OCT and GDx VCC showed only moderate sensitivity, these imaging devices may not substitute red-free fundus photography in clinical practice of glaucoma diagnosis.

Assessing intraocular pressure by rebound tonometer in rats with an air-filled anterior chamber.

PURPOSE: To compare rebound tonometer and cannulation as methods for measuring intraocular pressure (IOP) in rats. METHODS: The accuracy of the TonoLab rebound tonometer was determined in eight cannulated rat eyes. IOP was manipulated by changing air pressure from 20 to 100 mmHg at 10-mmHg intervals, and the IOP was measured with the rebound tonometer at each level. The average value of three repeated pressure readings was recorded. Correlation analysis and comparison with the Bland and Altman method were performed. The intraclass correlation coefficient was calculated to assess intraoperator variability. RESULTS: The IOP values measured with the TonoLab rebound tonometer were well correlated with the actual IOP (r (2) = 0.963, P = 0.01). The mean of the difference between the rebound tonometer and actual (cannulation) IOP was 7.41 +/- 7.87%. The intraclass correlation coefficient was 0.9, indicating low intraoperator variability. CONCLUSIONS: The rebound tonometer showed high accuracy and reliability for IOP measurement in rat eyes.