Short-term Clinical Outcomes of Micropulse TransscleralCyclophotocoagulation in Refractory Glaucoma Patients

Purpose@#We evaluated the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) in refractoryglaucoma patients. @*Methods@#A retrospective chart review was performed for 23 eyes of 23 patients with refractory glaucoma who were followed for6 months after MP-TSCPC. @*Results@#The mean preoperative intraocular pressure (IOP) was 39.3 ± 15.8 mmHg and the mean number of antiglaucoma medicationswas 2.6 ± 0.6. Both significantly decreased at 6 months to 23.8 ± 15.4 mmHg (p = 0.002) and 1.8 ± 1.1 (p = 0.018).Surgical success was defined as a postoperative IOP decrease from 6-21 mmHg or more than 20% reduction from baseline. Thesuccess rate was 65.2% at 6 months. Complications of MP-TSCPC included subconjunctival hemorrhage in 6 eyes (26.1%), ocularpain in 16 eyes (69.6%), anterior chamber inflammation in 17 eyes (73.9%), and hypotony in 2 eyes (8.7%). @*Conclusions@#MP-TSCPC in patients with refractory glaucoma showed a reduction in IOP and the number of antiglaucoma medicationsin the short-term. However, additional studies are needed to determine the optimal laser settings for maximum efficacyand safety.

Frequency and Causes of Segmentation Errors in Spectral Domain Optical Coherence Tomography Imaging in Glaucoma

PURPOSE: To determine the frequency and potential causes of segmentation errors in spectral domain optical coherence tomography (SD-OCT) imaging of retinal nerve fiber layer (RNFL) scans. METHODS: Segmentation errors for the RNFL thickness analysis were recorded during a retrospective chart review of 214 eye scans from 132 consecutive patients with glaucoma or glaucoma suspect who underwent a complete eye exam using Spectralis™ OCT scanning from August 2014 to November 2014. Segmentation errors were classified as inner, outer, inner and outer segmentation errors, and degraded images. The risk factors including age, sex, intraocular pressure, spherical equivalents, severity of glaucoma, and associated ocular disorders were evaluated using logistic regression analysis. RESULTS: A total of 71 eye scans included segmentation errors. Risk factors of inner segmentation error (8.9%) were age, epiretinal membrane, and degenerative myopia. Risk factors of outer segmentation error (29.9%) were age, peripapillary atrophy, posterior vitreous detachment, and severity of glaucoma. Risk factors of inner and outer segmentation errors (6.1%) were age and degenerative myopia. The single risk factor of degraded image (2.3%) was degenerative myopia. CONCLUSIONS: Segmentation errors for SD-OCT RNFL scans in glaucoma patients are common. Clinicians should carefully review the scans for segmentation errors when using SD-OCT images in glaucoma diagnosis or during patient follow-up.

Accuracy and Reliability of the Icare PRO in Enucleated Porcine Eyes - Upright and Horizontal Positions

PURPOSE: To compare the accuracy and reliability of intraocular pressure (IOP) measurements in enucleated porcine eyes using the Icare PRO in the upright and horizontal positions. METHODS: We designed an enucleated porcine eye model whose anterior chamber was cannulated with a 30-gauge needle, connected in parallel to a pneumatic pressure device. The reference pressure was manipulated by changing the air pressure from 70 to 10 mm Hg at 10 mm Hg intervals, and the IOP of porcine eyes was measured with the Icare PRO at each pressure. Correlation analysis, comparison using the Bland-Altman plot and Wilcoxon signed rank test, was performed to assess the accuracy of IOP measurements. Intraclass correlation coefficients were calculated to assess the intra-observer variability in the upright and horizontal positions, respectively. RESULTS: The IOP value in both upright and horizontal positions was well correlated with the reference pressure (r = 0.992 and 0.985, respectively). The Bland-Altman plot showed good agreement between the two positions. However, all IOP values in both positions were lower than the reference pressures. The IOP values in the horizontal position were significantly lower than those in the upright position at the a reference pressure of 50 mm Hg or greater. Values of intraclass correlation coefficient ranged from 0.911 to 0.984 when measured in the upright position and from 0.707 to 0.914 in the horizontal position. CONCLUSIONS: IOP measurements of Icare PRO in porcine eyes were remarkably lower than reference pressures controlled by the pneumatic method even though they showed a good correlation with reference values. The higher was the reference pressure, the greater was the degree of underestimation of IOP measurement in both positions. This trend was more pronounced in the horizontal position, and the reliability of IOP measurements was also lower than that in the upright position.

A Case of Persistent Shallow Anterior Chamber in Glaucoma Drainage Device Implantation Recovered by Fibrin Glue

PURPOSE: To report a case of persistent shallow anterior chamber after silicone tube intubation, recovered by fibrin glue in glaucoma drainage device implantation (GDI). CASE SUMMARY: A 42-year-old female, diagnosed with neovascular glaucoma at a local clinic visited our clinic for uncontrolled intraocular pressure (IOP) in her right eye. We performed GDI on her right eye. Scleral flap and paracentesis of the anterior chamber were performed. Then, a silicone tube was inserted into the anterior chamber. Despite repetitive infusion of balanced salt solution (BSS), the anterior chamber became persistently shallow due to peritubular leakage. After dropping the fibrin glue in the peritubular space and beneath the scleral flap, attachment occurred. No additional leakage was observed near the scleral flap and after infusion of BSS, a deep anterior chamber was maintained. One day after surgery, IOP in the right eye was 3 mm Hg, deep anterior chamber was maintained, and no leakage of aqueous humor into the conjunctiva occurred. Two months after surgery, IOP was 16 mm Hg and a deep anterior chamber was maintained. CONCLUSIONS: In cases of persistent shallow anterior chamber after silicone tube intubation in intraoperative GDI, the best methods to maintain the anterior chamber is by suture ligation of the peritubular loosened site or infusion of viscoelastic agent to anterior chamber. In the present case, applying the fibrin glue beneath the scleral flap apparently obstructed the peritubular infiltration.

Reliability Comparison of Rebound Tonometer at the Upright and Supine Position

PURPOSE: Rebound tonometer has been used to measure the intraocular pressure (IOP) in the supine as well as normal upright positions. We investigated the reliability of IOP measurements using the rebound tonometer in the upright and supine positions. METHODS: IOP was measured in 30 patients (60 eyes) with open-angle glaucoma who had no history of ocular surgery and no anterior segment pathology, in both the upright and supine positions using rebound tonometer (IcarePRO; Icare Finland Oy, Finland). The average IOP value after 6 measurements was recorded. We measured IOP repeatedly until 3 reliable values within normal limits of the measurement's variation were obtained. We calculated the intraclass correlation coefficient (ICC), coefficient of variation, and number of repeated measurements necessary to obtain 3 reliable IOP values in each position as measured by one examiner. RESULTS: ICC values for IOP measurements were 0.852 (95% confidence interval [CI], 0.784-0.903; p < 0.001) in the upright position and 0.684 (95% CI, 0.563-0.784; p < 0.027) in the supine position. Coefficient of variation was 8.7 +/- 0.1% in the upright position and 24.0 +/- 0.1% in the supine position. An average of 3.3 times of repeated measurements in the upright position and 6.2 times in the supine position were necessary to obtain 3 reliable IOP values within the normal range of standard deviation. CONCLUSIONS: When measuring IOP using the IcarePRO rebound tonometer, the measurement reliability was different between the upright and supine positions. Reproducibility of IOP measurements was lower in the upright than the supine position.

Diagnostic Abilities to Detect Glaucomatous Abnormality Using Normal Retinal Thickness Measured by Optical Coherence Tomography

PURPOSE: Recently, the introduction of spectral-domain optical coherence tomography (SD-OCT) has enabled measurement of retinal thickness in the posterior pole in 64 sectors. SD-OCT was used to evaluate the diagnostic effectiveness in detecting glaucomatous abnormality of visual field sensitivity. A normal value for retinal thickness was determined and then compared in corresponding local sectors. METHODS: Thirty healthy controls and 30 glaucoma subjects were evaluated. Macular thickness values from the 4 adjacent square cells in an 8 x 8 posterior pole retinal thickness map were averaged for a mean retinal thickness (MRT) value. A normative database was prepared using the data from the healthy eyes of this study to determine the diagnostic criteria for MRT. If the MRT value was <5% (Criteria A) or <1% (Criteria B) of the normative database, it was considered to be abnormal. The abnormalities of the MRT value for each diagnostic criteria were compared with the visual field sensitivity results in the corresponding positions. RESULTS: The concordance of abnormalities between MRT and visual field sensitivity at 16 measured points was low in both criteria A (Kappa value; -0.418~0.429) and B (Kappa value; -0.363~0.444). Based on the results of the visual field at each focal point, the sensitivities and specificities of MRT values using the 2 criteria ranged from 0% to 100%. CONCLUSIONS: In this study, MRT values showed low correlation and diagnostic ability to detect decreased sensitivity of the visual field in corresponding points, when customized criteria derived from a normative database were applied.

Changes of Peripapillary Retinal Nerve Fiber Layer Thickness Profile According to Aging in Myopic Eyes

PURPOSE: To evaluate the effects of age on the distributional variability of peripapillary retinal nerve fiber layer (RFNL) thickness measured by optical coherence tomography (OCT) in myopia. METHODS: Only the right eye of 64 myopic patients with long axial length (> or =24.5 mm) was included in the present study. The patients were divided into 2 age groups, 20 to 39 years of age and 40 to 59 years of age. Eventually, 42 subjects were selected and matched based on the difference of axial length not exceeding 0.5 mm between subjects in each group. The RFNL thickness was measured using Stratus OCT and average thickness, angular locations of double humps, and false-positive rate were compared. RESULTS: In both groups, the distribution of RNFL thickness in a double hump pattern was observed, which had a deviation to the temporal side only in the younger myopic eye group, but not in the middle-aged group. The middle-aged group had significantly thinner RNFL in 1, 7, and 8 clock-hour sectors compared to the younger myopic eyes (p < or = 0.02). Probability of abnormal OCT parameters at the 5% level of the 2 groups with the built-in RNFL normative database was not significantly different. CONCLUSIONS: The variability of RFNL thickness distribution related to axial length was less observed in the middle-aged group than the younger-aged group. These results should be considered in glaucoma diagnosis when using OCT.

Usefulness of Table Parameters of Stratus OCT in Detection of Localized Retinal Nerve Fiber Layer Defects

PURPOSE: To evaluate the usefulness of table parameters of Stratus optical coherence tomography (OCT) in order to detect localized retinal nerve fiber layer (RNFL) defects. METHODS: The present study included 86 glaucoma patients with only localized, wedge-shaped RNFL defects, as determined by red-free RNFL photographs. All subjects were tested fast RNFL scans, using of Stratus OCT. The sensitivity of the clock hour parameter and 11 table parameters of RNFL thickness average analysis were compared. RESULTS: The best parameters in the superior table parameter of the Stratus OCT were Smax, Savg, and Smax/Tavg (sensitivity = 36.7%, 36.7%, 36.7%, respectively). The best parameters in the inferior table parameter of the Stratus OCT were Iavg, Imax, and Imax/Smax (sensitivity = 63.8%, 59.4%, and 50.7%, respectively). However, all were significantly lower than the sensitivity of the clock hour parameter (superior RNFL defect: 60%; inferior RNFL defect: 84.1%). CONCLUSIONS: The usefulness of the table parameters of the Stratus OCT used to detect localized RNFL defects in glaucoma patients is considered low because of its low sensitivity.

Quantitative Analysis of Retinal Nerve Fiber Layer Thickness Profile in Myopic Eyes

PURPOSE: To investigate peripapillary retinal nerve fiber layer (RNFL) thickness profiles associated with myopia. METHODS: One hundred and twenty-seven normal eyes of 67 Korean adults were divided into three groups by spherical equivalent. All subjects were tested with fast RNFL scans of Stratus optical coherence tomography. The angular locations of superior and inferior maximal thickness points in relationship to a reference line drawn horizontally though the center of the scan circle were calculated from the raw data of scanned images (angle alpha, angle beta). Differences of angle alpha and angle beta were compared among the three groups. RESULTS: Angle alpha and angle beta were significantly different in three groups (ANOVA, p<0.001, respectively). Angle alpha and angle beta were also significantly different among the three groups for excluded eyes with tilted discs. CONCLUSIONS: The points of superior and inferior maximal peripapillary RNFL thickness were significantly different in three groups divided by spherical equivalent. As myopia becomes more severe, superior and inferior maximal peripapillary RNFL thickness points are located closer to the fovea.

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.

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.

Comparison of Stratus OCT and GDx VCC in Detecting Localized Retinal Nerve Fiber Layer Defects

PURPOSE: To compare the abilities of optical coherence tomography (Stratus OCT) and scanning laser polarimetry with variable corneal compensation (GDx VCC) in detecting localized retinal nerve fiber layer (RNFL) defects of red free photography METHODS: Thirty six normal subject and 50 patients with localized RNFL defects were included in this study. Only one eye per subject was considered. The peripapillary RNFL was divided into 12 clock-hour sectors and localized RNFL defects were evaluated in these 12 sectors. To compare the diagnostic performance of Stratus OCT and GDx VCC based on the findings of red-free photography, we calculated the sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of each analyzer using a criterion of 1 > or = clock hours abnormal at the <5% level. RESULTS: The sensitivity (78.6%), specificity (94.4%), and AUC (0.872) of Stratus OCT were not significantly different from those of GDx VCC (83.3%, 94.4%, and 0.882, respectively) (McNemar test, p=0.75, 1.00, and 0.82, respectively). However, the sensitivity (64.0%) of Stratus OCT for superior RNFL defect was significantly lower than that (84.8%) for inferior defect (Fisher's exact test, p=0.02). CONCLUSIONS: The sensitivity of the sector average of Stratus OCT and the deviation map of GDx VCC were fair in discriminating localized RNFL defects, and the specificity of those were excellent. In addition, the diagnostic performance was not significantly different between two analyzers.

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.