Yong Ho Sohn

Detection of glaucoma progression by assessment of segmented macular thickness data obtained using spectral domain optical coherence tomography.

PURPOSE We evaluated the clinical use of segmented macular layer thickness measurement in terms of glaucoma diagnosis and the ability to detect progression, and to compare such outcomes to those by circumpapillary retinal nerve fiber layer (cRNFLT) and total macular thickness (TMT) measurements. METHODS The study included 141 glaucomatous and 61 healthy eyes. All glaucomatous eyes were subjected to at least four spectral domain optical coherence tomography (SD-OCT) examinations (mean follow-up, 2.13 years). Segmented macular layers were the macular nerve fiber layer (NFL), ganglion cell and inner plexiform layer (GCA), and outer retinal layer (ORL; from outer plexiform layer to retinal pigment epithelium). Areas under receiver operating characteristic curves (AUCs) discriminating healthy from glaucomatous eyes were determined in baseline measurements. The sensitivity and specificity of these parameters in terms of glaucoma progression detection were determined, with reference to assessment of optic disc/retinal nerve fiber layer (RNFL) photographs/visual field (VF) deterioration as standard(s). RESULTS GCA afforded the best diagnostic performance among three macular layers. The AUC of the GCA thickness (GCAT) was less than that of cRNFLT (0.869 vs. 0.953, P = 0.018), but superior to that of TMT (0.790, P = 0.05). Of the eyes, 38 showed progression during follow-up by standard METHODS The sensitivities of TMT, GCAT, and cRNFLT values in terms of detection of progression were 14%, 8%, and 5%, respectively. CONCLUSIONS Although baseline cRNFL measurement was optimal in terms of glaucoma diagnosis, the GCAT and TMT showed similar levels of sensitivity in progression detection.

Macular Ganglion Cell Analysis for Early Detection of Glaucoma

PURPOSE To investigate the ability of Cirrus high-definition optical coherence tomography (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, CA) macular ganglion cell analysis (GCA) sector, deviation, and thickness maps to detect early glaucoma. DESIGN Cross-sectional study. PARTICIPANTS We enrolled 131 eyes with early glaucoma (mean deviation >-6.0 dB) and 132 age- and refractive error-matched healthy eyes. METHODS Macular GCA maps were obtained using Cirrus HD-OCT. The location, angular distance, and width of circumpapillary retinal nerve fiber layer (RNFL) defects were investigated by using red-free fundus photographs. The presence of a structural abnormality in the GCA map was defined as (1) yellow/red color codes in the sector map, (2) yellow/red pixels (>10) in the deviation map, and (3) blue areas in the thickness map. MAIN OUTCOME MEASURES The prevalence of and factors associated with the presence or absence of abnormal GCA findings were assessed. RESULTS Among the 131 glaucomatous eyes, 105 (80.2%), 115 (87.8%), and 104 (79.4%) showed structural abnormalities in the GCA sector, deviation, and thickness maps, respectively. The absence of abnormal findings in the GCA maps of glaucomatous eyes was associated with the presence of RNFL defects in the superior hemisphere, a greater angular distance between the fovea and the RNFL defect, a narrower width of the RNFL defect, less severe visual field defects, or an isolated peripheral nasal step (outside 10 degrees of fixation) (P<0.05). A greater angular distance of the RNFL defect remained significant in multivariate analyses (P<0.05). Among the 132 healthy eyes, 28 (21.2%), 37 (28.0%), and 20 (15.2%) had abnormal findings in the GCA sector, deviation, and thickness maps, respectively. The presence of abnormal GCA findings in healthy eyes was associated with a higher degree of myopic refractive error (P<0.05). CONCLUSIONS Cirrus HD-OCT GCA maps showed a good ability to detect early glaucoma. However, GCA maps did not show abnormal findings in glaucomatous eyes when the angular distance between fovea and RNFL defect was great. These findings should be considered when diagnosing early glaucoma using GCA maps.

Ability of cirrus high-definition spectral-domain optical coherence tomography clock-hour, deviation, and thickness maps in detecting photographic retinal nerve fiber layer abnormalities

PURPOSE To investigate the ability of clock-hour, deviation, and thickness maps of Cirrus high-definition spectral-domain optical coherence tomography (HD-OCT) in detecting retinal nerve fiber layer (RNFL) defects identified in red-free fundus photographs in eyes with early glaucoma (mean deviation >-6.0 dB). DESIGN Cross-sectional study. PARTICIPANTS Two hundred ninety-five eyes with glaucomatous RNFL defects with clear margins observed in red-free fundus photographs and 200 age-, sex-, and refractive error-matched healthy eyes were enrolled. METHODS The width and location of RNFL defects were evaluated by using the red-free fundus photograph. When a RNFL defect detected by red-free fundus photograph did not present as (1) yellow/red codes in the clock-hour map, (2) yellow/red pixels in the deviation map, or (3) blue/black areas in the thickness map, the event was classified as a misidentification of a photographic RNFL defect by Cirrus HD-OCT. In healthy eyes, the presence of false-positive RNFL color codes of Cirrus HD-OCT maps was investigated. MAIN OUTCOME MEASURES The prevalence of and factors associated with the (1) misidentification of photographic RNFL defects by Cirrus HD-OCT in eyes with glaucoma and (2) false-positive RNFL color codes of Cirrus HD-OCT maps in healthy eyes were assessed. RESULTS Among the 295 red-free fundus photographic RNFL defects from 295 eyes with glaucoma, 83 (28.1%), 27 (9.2%), and 0 (0%) defects were misidentified in the clock-hour, deviation, and thickness maps of Cirrus HD-OCT, respectively. Fifty-six defects (19.0%) were misidentified only in the clock-hour map and 27 (9.2%) in both the clock-hour and deviation maps. The misidentification of photographic RNFL defects by Cirrus HD-OCT was associated with a narrower width and a temporal location of RNFL defects (P<0.05). Among the 200 healthy eyes, 25 (12.5%), 30 (15.0%), and 12 (6.0%) eyes had false-positive RNFL color codes in clock-hour, deviation, and thickness maps of Cirrus HD-OCT, respectively. CONCLUSIONS Among the clock-hour, deviation, and thickness maps obtained with Cirrus HD-OCT, the thickness map showed the best diagnostic ability in detecting photographic RNFL defects. The RNFL thickness map may be a useful tool for the detection of RNFL defects in eyes with early glaucoma.

Concentration of Vascular Endothelial Growth Factor After Intracameral Bevacizumab Injection in Eyes With Neovascular Glaucoma

Purpose To study the concentration of vascular endothelial growth factor (VEGF) in the aqueous humor before and after intracameral injection of bevacizumab in eyes with neovascular glaucoma, and to detect the duration of an anti-VEGF effect of bevacizumab in the anterior chamber. Methods In this prospective interventional case series, 1.25 mg of bevacizumab was injected into the anterior chamber of five eyes in five neovascular glaucoma patients. Aqueous humor samples were obtained just before intracameral injection of bevacizumab and two weeks after injection. The concentrations of VEGF in the aqueous humor were measured using ELISA. To investigate corneal endothelial damage after intrecameral bevacizumab injection, specular microscopy was performed before injection and two weeks after injection. Slit lamp photo and iris fluorescent angiography was performed to determine the regression of iris neovascularization. Results After injection, substantial regression of neovascularization or fluorescein leakage was seen in all treated eyes. The VEGF concentrations in the aqueous humor in eyes with NVG were 1181.8±1248.3 pg/mL before intracameral injection of bevacizumab. Two weeks after injection, the VEGF concentrations decreased to 33.2±12.2 pg/mL (p=0.04, Wilcoxon signed rank test). There were no significant changes in IOP or corneal endothelial cells. Conclusions Intracameral bevacizumab injection can remarkably reduce iris neovascularization in neovascular glaucoma patients. VEGF levels were significantly decreased two weeks after injection and corneal toxicity was not observed during short term follow-up.

Effect of peripapillary retinoschisis on retinal nerve fibre layer thickness measurement in glaucomatous eyes

Background/aims To investigate the effect of peripapillary retinoschisis on the peripapillary retinal nerve fibre layer (RNFL) thickness measurement by using optical coherence tomography (OCT) in glaucomatous eyes. Methods We included 19 glaucomatous eyes of 19 subjects with peripapillary retinoschisis defined as the splitting of the peripapillary RNFL with schisis cavities (retinoschisis group) and 38 age-matched, refractive error-matched and visual field mean deviation-matched glaucomatous eyes from 38 subjects without peripapillary retinoschisis (control group) that had undergone RNFL thickness measurements by using OCT. RNFL thickness was compared between the two groups. For the retinoschisis group, the RNFL thicknesses prior to peripapillary retinoschisis formation, at the time of peripapillary retinoschisis, and after peripapillary retinoschisis resolution were compared. Results The average RNFL was greater in the eyes in the retinoschisis group (median, 81.6 µm) than in those in the control group (median, 69.7 µm, p=0.009). In the retinoschisis group, the average RNFL thickness at the time of peripapillary retinoschisis was greater than that prior to peripapillary retinoschisis formation (p=0.013) or after peripapillary retinoschisis resolution (p=0.001). The RNFL thickness was not different prior to peripapillary retinoschisis formation and after peripapillary retinoschisis resolution (p>0.05). Conclusions Transient increase in RNFL thickness as determined by OCT was observed in glaucomatous eyes with peripapillary retinoschisis. Caution is warranted when interpreting the RNFL thickness measurement in eyes with peripapillary retinoschisis.

Bilateral Spontaneous Anterior Lens Dislocation in a Retinitis Pigmentosa Patient

Purpose To report a case of bilateral spontaneous anterior lens dislocation associated with retinitis pigmentosa (RP). Methods A 45-year-old male with RP presented with elevated intraocular pressure (IOP) in the right eye and was treated with laser iridotomy (LI). After LI, complete crystalline lens dislocation into the anterior chamber occurred. Surgical intervention, including anterior vitrectomy, intracapsular cataract extraction (ICCE), and IOL scleral fixation was performed. Two years later, the same episode occurred in his left eye and a similar treatment was done. Results Surgery was successful in both eyes. Conclusions This is the first report of bilateral spontaneous anterior lens dislocation in a RP patient.

Changes in retinal nerve fiber layer thickness after optic disc hemorrhage in glaucomatous eyes.

Purpose:The aim of this study was to investigate the changes in longitudinal retinal nerve fiber layer thickness (RNFLT) as determined by spectral-domain optical coherence tomography (OCT) after optic disc hemorrhage (DH) in glaucomatous eyes. Methods:A total of 65 eyes with unilateral DH and 65 contralateral eyes without DH were subjected to RNFLT measurements by using OCT at the time of DH detection and at 1 year (12±2 mo) and 2 years (24±2 mo) later. For the definition of event-based significant RNFLT changes (a change beyond the upper limit of the 95% confidence interval of test-retest variability), 50 eyes with stable glaucoma without DH that had undergone OCT examinations 3 times with a 1-year interval were also enrolled. Clock-hour sector RNFLT in the eyes with DH and clock-hour sector RNFLT at equivalent locations in the contralateral eyes without DH were analyzed to assess localized and spatially compatible RNFLT changes associated with DH. Results:Of the eyes with DH, 38.5% showed decrease in RNFLT and 6.2% showed increase in RNFLT 1 year after DH detection, whereas 58.5% showed decrease in RNFLT and no eye showed increase in RNFLT 2 years after DH detection. Significant decreases in RNFLT in the eyes with DH were associated with the presence of recurrent DH and greater baseline RNFLT (P<0.05). Of the contralateral eyes without DH, 4.6% and 15.4% showed decrease in RNFLT 1 and 2 years after DH detection, respectively. Conclusions:In the glaucomatous eyes, DH was associated with progressive decrease in RNFLT as determined by OCT, especially in the eyes with recurrent DH and greater baseline RNFLT.

The relationship between optical coherence tomography and scanning laser polarimetry measurements in glaucoma.

Purpose To investigate the relationship between optical coherence tomography (OCT) and scanning laser polarimetry (SLP) in measuring peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes. Methods Fifty glaucomatous eyes were evaluated in this study. Evaluations were analyzed two ways. First, parameters of the Stratus OCT (average thickness, superior/inferior average) and GDx VCC (TSNIT average, nerve fiber indicator (NFI), superior/inferior average) were correlated using the Pearsons correlation coefficient (r). Secondly, comparison (r) of these parameters was completed using the mean deviation (MD) of visual field defect. Results The following parameters were found to be significantly correlated (P<0.005). TSNIT average/average thickness (r=0.673), NFI/average thickness (r=-0.742), superior average (r=0.841), and inferior average (r=0.736). In the correlation analysis using the severity of visual field defect, all these parameters had statistically meaningful correlations (P<0.005). Conclusions GDx VCC and Stratus OCT are highly correlated in glaucomatous eyes. Therefore, peripapillary RNFL thickness measured by Stratus OCT and GDx VCC may be equally helpful in the diagnosis of glaucoma.

Quantitative Analysis of Optic Disc Color

Purpose To evaluate the reproducibility of ImageJ software in analyzing the color of the optic disc. Methods One hundred twelve normal participants (56 males and 56 females) were enrolled in this study. The image of the optic disc was taken using Kowa digital disc photo-graphy, and the gray scales of the nasal rim (NR), brightest cupping center (BCC) and largest inferior retinal vein (IRV) were calculated using histogram in ImageJ. Three different observers calculated the gray scales three separate times. Reproducibility was assessed using the interclass correlation coefficient (ICC). Results The mean age of the participants was 50.6 years old (range, 11 to 82 years). The mean gray scales of the nasal rim were 91.81, 94.91, and 93.24; those of the brightest cupping center were 174.84, 179.94, and 177.76; and those of the largest inferior retinal vein were 61.85, 53.48, and 56.73 for observers 1, 2, and 3, respectively. Inter-observer reproducibility for NR, BCC and IRV was considered good based upon ICC values of 0.944, 0.860, and 0.789 for observers 1, 2, and 3, respectively. Significant age-related differences between the values of the brightest cupping center were noted, and the gray scale score was decreased in the older participants (p < 0.001). Conclusions The gray scale of the brightest cupping center diminished with age. ImageJ can be a useful objective tool with high reproducibility in the analysis of optic disc color.

Agreement of Retinal Nerve Fiber Layer Defect Location Between Red-Free Fundus Photography and Cirrus HD-OCT Maps

Abstract Purpose: To investigate the agreement of angular locations of retinal nerve fiber layer (RNFL) defect margins in glaucomatous eyes by using red-free fundus photographs and Cirrus high-definition optical coherence tomography (OCT) RNFL deviation and thickness maps. Methods: We examined 380 RNFL defects that showed clear margins in red-free fundus photographs. The OCT deviation and thickness maps were overlaid on the corresponding red-free fundus photographs. A reference line was drawn between the disc center and the macular center. Lines were also drawn between the optic disc center and the point where the RNFL defect margins crossed the OCT scan circle. The angle between the reference and defect-margin lines defined the angular location of the defect margin. Angular locations of proximal (nearest to the reference) and distal (farthest from the reference) RNFL defect margins on OCT deviation and thickness maps were compared to the locations on red-free fundus photographs. Results: The angular locations of proximal and distal RNFL defect margins on OCT thickness maps showed good agreement with red-free fundus photographs. However, OCT deviation maps showed greater angular locations for both proximal and distal RNFL defect margins compared with red-free fundus photographs, especially in eyes with higher myopia (p < 0.05). Conclusions: Red-free fundus photographs and OCT thickness maps showed good agreement for the RNFL defect margin identification. However, this was not the case for deviation maps, especially in myopic eyes. This finding should be considered when evaluating RNFL defects using OCT maps.