Seung Hyen Lee

OCT Angiography of the Peripapillary Retina in Primary Open-Angle Glaucoma.

Purpose The purpose of this study was to investigate the topographic relationship between the decreased parapapillary retinal microvasculature as assessed by optical coherence tomography angiography (OCTA) and retinal nerve fiber layer (RNFL) defect in eyes with primary open-angle glaucoma (POAG) and a localized RNFL defect. Methods The peripapillary retinal circulation was evaluated using the OCTA centered on the optic nerve head in 98 POAG eyes having a localized RNFL defect and 45 healthy control eyes. A vascular impairment (VI) was identified in OCTA by the presence of a sign indicating decreased microvasculature. The frequencies of VI were compared between the POAG and control groups, and the topographic correlation between the VI and the RNFL defect identified in red-free fundus photographs was determined in the POAG group. Results The VI was observed as an area of decreased density of the microvascular network of the retina in 100% of the POAG eyes. The VI exactly coincided with the RNFL defect evident in red-free fundus photographs in terms of both the location and extent (Pearsons correlation coefficient = 0.997 and 0.988, respectively, all P < 0.001). None of the control eyes exhibited VI in OCTA. Conclusions Decreased parapapillary microvasculature of the retina determined by OCTA was found at the location of RNFL defect in POAG patients. This finding suggests that the decreased retinal microvasculature is likely secondary loss or closure of capillaries at the area of glaucomatous RNFL atrophy.

Parapapillary Choroidal Microvasculature Dropout in Glaucoma: A Comparison between Optical Coherence Tomography Angiography and Indocyanine Green Angiography.

PURPOSE To investigate whether the parapapillary choroidal microvasculature dropout (MvD) determined by optical coherence tomography angiography (OCTA) in glaucomatous eyes indicates a true perfusion defect and whether the MvD accurately represents the area of nonperfusion. DESIGN Observational case series. PARTICIPANTS Thirty primary open-angle glaucoma (POAG) patients with choroidal MvD as determined by OCTA and 13 POAG patients without this dropout. METHODS Peripapillary circulation was evaluated using both OCTA and indocyanine green angiography (ICGA). For OCTA, the choroidal microvasculature was evaluated using 4.5×4.5-mm choroid-disc vessel density maps of OCTA images of the optic nerve head. An MvD was identified in OCTA by the presence of a capillary dropout. A filling defect observed in ICGA was defined as a perfusion defect (ICGPD). MAIN OUTCOME MEASURES The topographic correlations between MvD and ICGPD determined based on their circumferential extent, location, and area. RESULTS The ICGPD was observed as a sectoral filling defect in the 30 POAG patients exhibiting MvD and appeared identical to the MvD in terms of the shape and location. The circumferential extent, location, and area of ICGPD did not differ from those of the MvD (all P > 0.05). The ICGPD was not found in any of the eyes not having the MvD. CONCLUSIONS A localized MvD observed in the parapapillary choroid using OCTA coincided with the ICGPD detected by ICGA. These findings indicate that OCTA accurately images impaired parapapillary choroidal circulation.

Reduction of the Lamina Cribrosa Curvature After Trabeculectomy in Glaucoma

Purpose To investigate whether the lamina cribrosa (LC) curvature is decreased after trabeculectomy. Methods Thirty-nine eyes of 39 patients with primary open-angle glaucoma who underwent trabeculectomy were included. Optic nerves were scanned by using enhanced-depth-imaging spectral-domain optical coherence tomography before and after trabeculectomy. The LC curvature was assessed by measuring the LC curvature index (LCCI) in seven horizontal B-scan images in each eye. Results The LCCI was significantly smaller at postoperative 6 months than at the preoperative level in all seven planes (all P < 0.001). Preoperative LCCI was associated with younger age at superior midperiphery, midhorizontal plane, inferior midperiphery (all P ≤ 0.005) and higher preoperative intraocular pressure (IOP) at superior and inferior midperiphery (both P = 0.039). Younger age and larger preoperative LCCI were associated with a larger reduction of the LCCI at all three locations (P = 0.003 and 0.031 at superior midperiphery, P = 0.011 and 0.001 at midhorizontal plane, and P = 0.014 and 0.005 at inferior midperiphery, respectively), whereas the percentage IOP lowering was associated at superior and inferior midperiphery (P = 0.017 and 0.047, respectively). Conclusions Lamina cribrosa curvature was reduced after trabeculectomy. This finding suggests that LC curvature may have value as a parameter relevant to optic nerve head biomechanics.

Diagnostic Power of Lamina Cribrosa Depth and Curvature in GlaucomaDiagnostic Power of LC Depth and Curvature

Purpose To compare the capability of the lamina cribrosa depth (LCD) and lamina cribrosa (LC) curvature in discriminating between eyes with primary open-angle glaucoma (POAG) and healthy eyes. Methods Seventy-seven eyes of 77 patients with POAG and 77 eyes of 77 healthy subjects who were matched for age, sex, and axial length were included. The LCD and lamina cribrosa curvature index (LCCI) were measured in B-scan images obtained using swept-source optical coherence tomography at seven locations spaced equidistantly across the vertical optic disc diameter. The mean values of the measurements made at seven points of the LC were defined as the average LCD and LCCI. Results The average LCD (527.0 ± 116.4 vs. 413.3 ± 80.4 μm, P < 0.001) and average LCCI (10.97 ± 2.59 vs. 6.81 ± 1.43, P < 0.001) were significantly larger in POAG eyes than in the matched healthy subjects (all seven locations, P < 0.001). The area under the receiver operating characteristic curve (AUC) was significantly larger for the LCCI than the LCD (0.921 vs. 0.784, P < 0.001). The intraocular pressure was positively associated with average LCD and LCCI in healthy subjects (P = 0.021 and P < 0.001, respectively) and POAG patients (P = 0.011 and P < 0.001, respectively). Male sex was associated with larger average LCCI (P = 0.013) and LCD (P = 0.008) in POAG. Conclusions The LCCI had significantly better discriminating capability between POAG and healthy eyes than LCD. This finding suggests that the LCCI may serve better than the LCD for improved glaucoma management.

Underlying Microstructure of Parapapillary Deep-Layer Capillary Dropout Identified by Optical Coherence Tomography Angiography

Purpose To characterize the microstructure underlying the parapapillary deep-layer microvasculature dropout (MvD) identified by optical coherence tomography (OCT) angiography (OCTA) in eyes with primary open-angle glaucoma (POAG). Methods Parapapillary MvD was defined as a focal sectoral capillary dropout without any visible microvascular network identified in deep-layer en face images obtained using swept-source OCTA. The peripapillary microstructure was characterized in 188 POAG patients with MvD in the parapapillary deep layer. Twelve radial optic nerve images were obtained using swept-source OCT to examine the peripapillary structure and measure the juxtapapillary choroidal thickness (JPCT). The JPCT was also measured in 72 age-matched POAG eyes having β-zone parapapillary atrophy (PPA) without an MvD (control group). Results Microvascular dropouts were observed within the areas with a PPA involving the β-zone, γ-zone, and a mixture of both zones in 72, 57, and 59 eyes, respectively. Choroid of noticeable thickness was observed without obvious thinning in the PPA area when the MvD was associated with the β-zone. The JPCT was comparable between eyes with MvD and control eyes. There was no distinguishable feature in the microstructure of the γ-zone, regardless of whether it was associated with MvD. Conclusions Optical coherence tomography angiography showed MvDs in the parapapillary deep layers that were associated with both β- and γ-zones within the PPAs. The microstructure of PPAs with MvDs was not distinguishable from that of PPAs not associated with MvDs.

Parapapillary Deep-Layer Microvasculature Dropout in Glaucoma: Topographic Association With Glaucomatous Damage

Purpose The purpose of this article was to compare the frequencies of the parapapillary deep-layer microvasculature dropout (MvD) detected by optical coherence tomography angiography in eyes with primary open-angle glaucoma (POAG) and healthy eyes and to determine the topographic correlation between the MvD and the glaucomatous retinal nerve fiber layer (RNFL) defect in POAG eyes. Methods Microvasculature in the peripapillary deep-layer was evaluated in 150 POAG patients and 45 healthy controls using swept-source optical coherence tomography angiography to identify an MvD. Frequencies of MvDs were compared between the POAG and control groups. In POAG eyes with MvD, topographic correlation was assessed between the MvD and the RNFL defect defined based on the optical coherence tomography circumpapillary RNFL thickness measurement. Results MvD was observed as a sectoral filling defect in the parapapillary deep-layer in 53.9% (n = 62) of the POAG eyes, whereas none of the control eyes exhibited an MvD. POAG eyes with MvD had a thinner global RNFL (P < 0.001) and worse visual field mean deviation (P = 0.042) and were more myopic (P = 0.029), with axial length being longer (P = 0.046) than those without MvD. There was a good agreement between the circumferential extent and location of MvD and those of RNFL defect (95% limits of agreement of the difference ranged from -23.4 to 21.9° and -16.2 to 17.0°, respectively). Conclusions MvD was identified in the parapapillary deep layer exclusively in POAG eyes at the location of glaucomatous damage using optical coherence tomography angiography. The finding suggests that peripapillary deep-layer circulation is directly related to the glaucomatous optic neuropathy.

Retinal Nerve Fiber Layer Thickness Measurement Comparison Using Spectral Domain and Swept Source Optical Coherence Tomography.

Purpose To investigate the retinal nerve fiber layer (RNFL) thickness concordance when measured by spectral domain (SD) and swept source (SS) optical coherence tomography (OCT), and to compare glaucoma-discriminating capability. Methods RNFL thicknesses were measured with the scan circle, centered on the optic nerve head, in 55 healthy, 41 glaucoma suspected, and 87 glaucomatous eyes. The RNFL thickness measured by the SD-OCT (sdRNFL thickness) and SS-OCT (ssRNFL thickness) were compared using the t-test. Bland-Altman analysis was performed to examine their agreement. We compared areas under the receiver operating characteristics curve and examined sdRNFL and ssRNFL thickness for discriminating glaucomatous eyes from healthy eyes, and from glaucoma suspect eyes. Results The average ssRNFL thickness was significantly greater than sdRNFL thickness in healthy (110.0 ± 7.9 vs. 100.1 ± 6.8 µm, p < 0.001), glaucoma suspect (96.8 ± 9.3 vs. 89.6 ± 7.9 µm, p < 0.001), and glaucomatous eyes (74.3 ± 14.2 vs. 69.1 ± 12.4 µm, p = 0.011). Bland-Altman analysis showed that there was a tendency for the difference between ssRNFL and sdRNFL to increase in eyes with thicker RNFL. The area under the curves of the average sdRNFL and ssRNFL thickness for discriminating glaucomatous eyes from healthy eyes (0.984 vs. 0.986, p = 0.491) and glaucoma suspect eyes (0.936 vs. 0.918, p = 0.132) were comparable. Conclusions There was a tendency for ssRNFL thickness to increase, compared with sdRNFL thickness, in eyes with thicker RNFL. The ssRNFL thickness had comparable diagnostic capability compared with sdRNFL thickness for discriminating glaucomatous eyes from healthy eyes and glaucoma suspect eyes.

Structural characteristics of the acquired optic disc pit and the rate of progressive retinal nerve fiber layer thinning in primary open-angle glaucoma.

IMPORTANCE The optic disc pit (ODP) has been considered a region of localized susceptibility to the damage of glaucoma. OBJECTIVE To determine whether the rate of retinal nerve fiber layer (RNFL) thinning differs according to the presence and structural characteristics of an ODP in primary open-angle glaucoma. DESIGN, SETTING, AND PARTICIPANTS We performed a prospective case-control study that included 163 eyes with primary open-angle glaucoma (83 with an ODP and 80 without an ODP) from Glaucoma Clinic of Seoul National University Bundang Hospital. Participants were enrolled from the ongoing Investigating Glaucoma Progression Study from January 1, 2012, through May 31, 2014. Mean (SD) follow-up was 3.32 (0.49) years (through May 31, 2014). Optic nerve heads underwent swept-source optical coherence tomography (OCT) to determine the presence of focal lamina cribrosa alteration and its structural characteristics. Eyes with and without photographic ODPs and corresponding microscopic laminar alterations were assigned to the ODP and non-ODP groups, respectively. The rates of progressive thinning of global and 6 sectoral spectral-domain OCT RNFL thicknesses were determined by linear regression and compared between the 2 groups. We used a general linear model to determine the factors associated with the rate of RNFL thinning; data obtained from September 21, 2009, through May 31, 2014, were used to calculate the rate of RNFL thinning. MAIN OUTCOMES AND MEASURES The relationship between the presence and structural characteristics of ODPs and the rate of progressive OCT RNFL thinning. RESULTS Thinning of the RNFL was faster in the ODP group than in the non-ODP group in the global (mean [SD], -1.44 [1.31] vs -0.93 [1.10] [95% CI, -0.97 to -0.19] μm/y; P = .008), temporoinferior (mean [SD], -4.17 [4.15] vs -1.97 [3.26] [95% CI, -3.36 to -1.04] μm/y; P < .001), and temporal (mean [SD], -1.92 [2.62] vs -0.89 [1.62] [95% CI, -1.70 to -0.35] μm/y; P = .003) sectors. The rate of RNFL thinning was maximum in the temporoinferior sector (mean [SD], -4.17 [4.15] μm/y) and corresponded to the frequency distribution of ODPs. Regression analysis revealed that faster global RNFL thinning was related to a higher untreated intraocular pressure (β = -0.07; 95% CI, -0.11 to -0.03; P = .001), episodes of disc hemorrhage (β = -0.74; 95% CI, -1.79 to 0.31; P = .003), the presence of β-zone parapapillary atrophy (β = -0.47; 95% CI, -1.13 to 0.20; P = .02), and the presence of ODPs (β = -0.41; 95% CI, -1.14 to 0.32; P = .02). The maximum rate of RNFL thinning was associated with higher untreated intraocular pressure (β = -0.24; 95% CI, -0.35 to -0.13; P < .001), disc hemorrhage (β = -1.54; 95% CI, -2.88 to -0.19; P < .001), and the presence (β = -1.04; 95% CI, -2.14 to 0.07; P = .004), far-peripheral location (β = -1.75; 95% CI, -3.05 to -0.46; P = .008), and partial-thickness depth (β = -1.45; 95% CI, -2.75 to -0.16; P = .03) of an ODP. CONCLUSIONS AND RELEVANCE The presence and structural characteristics of ODPs were associated with global and focal progression as assessed by the rate of OCT RNFL thinning. The assessment of ODP structure using swept-source OCT may help to predict the location of future progression.

Disc haemorrhage associated with an enlarged peripapillary intrachoroidal cavitation in a non-glaucomatous myopic eye: a case report

BackgroundDisc haemorrhage (DH) is considered a characteristic sign of glaucoma, but its causative mechanism remains to be determined. We present a case of DH that occurred in association with an enlarged peripapillary intrachoroidal cavitation in a non-glaucomatous eye.Case presentationA 35-year-old woman was evaluated for a DH that had been detected during a preoperative examination for myopic refractive surgery. Enhanced depth imaging spectral-domain optical coherence tomography imaging of the optic nerve revealed a peripapillary intrachoroidal cavitation adjacent to the DH. The DH was also present at the 1-year follow-up, but had been completely absorbed at the 2-year follow-up, respectively with an enlargement and shrinkage of the intrachoroidal cavitation and prelaminar tissue schisis. Glaucomatous optic nerve change was not observed during the entire follow-up.ConclusionDH can be caused by mechanical damage to capillaries from microscopic changes in peripapillary tissues such as enlargement of the intrachoroidal cavitation, regardless of the presence of glaucoma.

Ocular and Clinical Characteristics Associated with the Extent of Posterior Lamina Cribrosa Curve in Normal Tension Glaucoma

Although normal-tension glaucoma (NTG) is pathogenetically heterogenous, there have been few attempts to subclassify NTG patients according to the mechanism and anatomy of optic nerve damage. This cross-sectional study was performed to investigate differences in the clinical and ocular characteristics between NTG patient groups stratified according to the degree of posterior lamina cribrosa (LC) curve which was assessed by calculating LC curvature index (LCCI). A total of 101 eyes of 101 treatment naïve NTG patients were included. The optic nerve head was imaged using enhanced-depth-imaging spectral-domain optical coherence tomography in three horizontal B-scan images in each eye. The patients were divided into two groups based on the magnitude of LCCI using a cutoff of known upper 95 percentile value in healthy subjects: a steeply curved LC group (Group 1, 75 eyes, 74.3%) and a relatively flat LC group (Group 2, 26 eyes, 25.7%). NTG eyes with relatively flat LC had lower intraocular pressure, and were associated with greater parapapillary structural alternation and systemic risk factors. These data suggest that assessment of LC morphology may help clinicians seek additional risk factors and make inferences about the mechanism of optic nerve damage in individual patients.