Factors associated with deep circulation in the peripapillary chorioretinal atrophy zone in normal-tension glaucoma with myopic disc.

PURPOSE: To investigate factors associated with choroidal microcirculation in the peripapillary chorioretinal atrophy (PPA) zone in eyes with normal-tension glaucoma (NTG) and myopic disc. METHODS: In 100 eyes of 100 NTG patients with myopic disc and 20 eyes of 20 age-matched myopic controls, 4.5 × 4.5 mm scans were made of the optic nerve head with optical coherence tomography angiography (OCTA). Peripapillary chorioretinal atrophy (PPA) area and PPA superficial choroidal image intensity (PPA-CI) were calculated with image j software. Clinical characteristics, laser speckle flowgraphy-measured mean blur rate in the temporal tissue area (temporal MT), the central thresholds (the averaged standard automated perimetry-measured visual field thresholds in the four paracentral points) and 3D-OCT-measured ganglion cell complex thickness in the papillomacular bundle (PMB-GCCT) were recorded. RESULTS: The NTG patients had significantly lower intraocular pressure, PMB-GCCT and central threshold values, and a larger PPA area, than the controls. The area under the receiver operating characteristics curve to differentiate NTG with parafoveal scotoma (PFS) from controls was 0.76 for temporal MT, 0.85 for PPA-CI and 0.87 for PMB-GCCT. Univariate and multivariate analyses revealed that PPA-CI was negatively correlated with age, pulse rate, best-corrected visual acuity, axial length and PPA area, and positively correlated with temporal MT, PMB-GCCT and the central thresholds. CONCLUSION: Peripapillary chorioretinal atrophy (PPA)-CI was associated with temporal MT, ageing, bradycardia, axial length elongation and changes in central retinal structure and visual function in patients with NTG and myopic disc. Thus, microcirculation deep within the PPA zone might be a clinically useful biomarker of PFS in NTG.

Evaluation of retinal nerve fiber layer defect using wide-field en-face swept-source OCT images by applying the inner limiting membrane flattening.

PURPOSE: The assessment of retinal nerve fiber layer defects (RNFLDs) is a useful part of glaucoma care. Here, we obtained en-face images of retinal layers below the inner limiting membrane (ILM) with swept source-optical coherence tomography (SS-OCT), and measured RNFLD angle with new software. METHODS: This study included 105 eyes of 105 normal tension glaucoma (NTG) patients (age, 59.8 ± 13.2). Exclusion criteria were best-corrected visual acuity < 0.5, axial length > 28 mm, non-glaucoma ocular disease, and systemic disease affecting the visual field. We obtained 12 x 9 mm 3D volume scans centered on the macula with SS-OCT (DRI OCT-1, Topcon), and from these scans, created 3 averaged en-face images, each comprising 7 horizontal en-face images (total thickness: 18.2 µm). We labeled these averaged images, according to their depth below the ILM, as en-face images 1 (shallowest), 2 (middle) and 3 (deepest). In each image, a circle was drawn centered on the disc, with a radius of half the distance between the centers of the disc and macula. The investigator marked points where the edge of the RNFLD intersected this circle, and RNFLD angle (RNFLDA) was calculated with new software. Finally, we analyzed the association between RNFLDA, cpRNFLT, weighted RGC count (wrgc) and Humphrey field analyzer (HFA)-measured mean deviation (MD) and hemifield total deviation (TD), both overall and in each hemifield. RESULTS: En-face image 2 had the highest interclass reproducibility for measuring RNFLDA (intra-rater intraclass correlation coefficient (ICC): 0.988, inter-rater ICC: 0.962). The correlation coefficients with RNFLDA were: HFA MD, -0.60; superior TD, -0.73; inferior TD, -0.69; overall cpRNFLT, -0.27; superior hemifield cpRNFLT, -0.39; and inferior hemifield cpRNFLT, -0.53 (all p<0.001). CONCLUSIONS: RNFLDA measured in SS-OCT images had high reproducibility and was correlated to glaucoma severity. Our new method may be a valuable future part of glaucoma care.

Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography.

PURPOSE: To investigate the influence of various risk factors on thinning of the lamina cribrosa (LC), as measured with swept-source optical coherence tomography (SS-OCT; Topcon). METHODS: This retrospective study comprised 150 eyes of 150 patients: 22 normal subjects, 28 preperimetric glaucoma (PPG) patients, and 100 open-angle glaucoma patients. Average LC thickness was determined in a 3 x 3 mm cube scan of the optic disc, over which a 4 x 4 grid of 16 points was superimposed (interpoint distance: 175 µm), centered on the circular Bruch's membrane opening. The borders of the LC were defined as the visible limits of the LC pores. The correlation of LC thickness with Humphrey field analyzer-measured mean deviation (MD; SITA standard 24-2), circumpapillary retinal nerve fiber layer thickness (cpRNFLT), the vertical cup-to-disc (C/D) ratio, and tissue mean blur rate (MBR) was determined with Spearman's rank correlation coefficient. The relationship of LC thickness with age, axial length, intraocular pressure (IOP), MD, the vertical C/D ratio, central corneal thickness (CCT), and tissue MBR was determined with multiple regression analysis. Average LC thickness and the correlation between LC thickness and MD were compared in patients with the glaucomatous enlargement (GE) optic disc type and those with non-GE disc types, as classified with Nicolela's method. RESULTS: We found that average LC thickness in the 16 grid points was significantly associated with overall LC thickness (r = 0.77, P < 0.001). The measurement time for this area was 12.4 ± 2.4 minutes. Average LC thickness in this area had a correlation coefficient of 0.57 with cpRNFLT (P < 0.001) and 0.46 (P < 0.001) with MD. Average LC thickness differed significantly between the groups (normal: 268 ± 23 µm, PPG: 248 ± 13 µm, OAG: 233 ± 20 µm). Multiple regression analysis showed that MD (ß = 0.29, P = 0.013), vertical C/D ratio (ß = -0.25, P = 0.020) and tissue MBR (ß = 0.20, P = 0.034) were independent variables significantly affecting LC thickness, but age, axial length, IOP, and CCT were not. LC thickness was significantly lower in the GE patients (233.9 ± 17.3 µm) than the non-GE patients (243.6 ± 19.5 µm, P = 0.040). The correlation coefficient between MD and LC thickness was 0.58 (P < 0.001) in the GE patients and 0.39 (P = 0.013) in the non-GE patients. CONCLUSION: Cupping formation and tissue blood flow were independently correlated to LC thinning. Glaucoma patients with the GE disc type, who predominantly have large cupping, had lower LC thickness even with similar glaucoma severity.

3D evaluation of the lamina cribrosa with swept-source optical coherence tomography in normal tension glaucoma.

PURPOSE: Although the lamina cribrosa (LC) is the primary site of axonal damage in glaucoma, adequate methods to image and measure it are currently lacking. Here, we describe a noninvasive, in vivo method of evaluating the LC, based on swept-source optical coherence tomography (SS-OCT), and determine this method's ability to quantify LC thickness. METHODS: This study comprised 54 eyes, including normal (n = 18), preperimetric glaucoma (PPG; n = 18), and normal tension glaucoma (NTG; n = 18) eyes. We used SS-OCT to obtain 3 x 3 mm cube scans of an area centered on the optic disc, and then synchronized reconstructed B- and en-face images from this data. We identified the LC in these B-scan images by marking the visible borders of the LC pores. We marked points on the anterior and posterior borders of the LC in 12 B-scan images in order to create a skeleton model of the LC. Finally, we used B-spline interpolation to form a 3D model of the LC, including only reliably measured scan areas. We calculated the average LC thickness (avgLCT) in this model and used Spearman's rank correlation coefficient to compare it with circumpapillary retinal nerve fiber layer thickness (cpRNFLT). RESULTS: We found that the correlation coefficient of avgLCT and cpRNFLT was 0.64 (p < 0.01). The coefficient of variation for avgLCT was 5.1%. AvgLCT differed significantly in the groups (normal: 282.6 ± 20.6 µm, PPG: 261.4 ± 15.8 µm, NTG: 232.6 ± 33.3 µm). The normal, PPG and NTG groups did not significantly differ in age, sex, refractive error or intraocular pressure (IOP), although the normal and NTG groups differed significantly in cpRNFLT and Humphrey field analyzer measurements of mean deviation. CONCLUSION: Thus, our results indicate that the parameters of our newly developed method of measuring LC thickness with SS-OCT may provide useful and important data for glaucoma diagnosis and research.

Topographical correlation between macular layer thickness and clockwise circumpapillary retinal nerve fiber layer sectors in patients with normal tension glaucoma.

PURPOSE: To define topographical areas of the macula in optical coherence tomography (OCT) scans by identifying regions in which macular retinal nerve fiber layer (mRNFL) and ganglion cell-inner plexiform layer (mGCL + IPL) thickness was highly correlated with clockwise circumpapillary RNFL (cpRNFL) thickness in patients with normal tension glaucoma (NTG). METHODS: This study included 101 eyes of 101 patients with mild or moderate NTG. CpRNFL, mRNFL, and mGCL + IPL thickness were assessed with spectral-domain OCT (3D OCT-2000). The region of interest (6 × 6 mm square) was centered on the fovea and layer thickness was measured at each point on a 10 × 10 grid. Spearman's rank correlation coefficient was determined between each temporal clockwise sector (7, 8, 9, 10, 11 o'clock) of the cpRNFL and each grid point in the mRNFL and mGCL + IPL. Grid points were defined as correlated to specific clockwise sectors when the correlation coefficient was more than 0.4. To validate the areas comprised by these points, they were superimposed on a swept-source OCT image (12 × 9 mm, EnView software, Topcon) showing the anatomical trajectory of nerve fiber defects. RESULTS: Macular areas with a high correlation coefficient (r ≥ 0.4, p < 0.05) to clockwise cpRNFL were identified. The number of grid points in the mRNFL and mGCL + IPL correlated to specific clockwise cpRNFL sectors was, respectively, 40 and 18 (7 o'clock), 41 and 22 (8), 33 and 44 (9), 39 and 39 (10), and 18 and 19 (11) (r = 0.40-0.79). Interestingly, the distribution of mRNFL sectors closely matched the RNFL defects in the OCT image, although the mGCL + IPL sectors differed and were closer to the fovea than the mRNFL sectors. CONCLUSION: The identification of these topographical macular areas, and the different layouts in the mRNFL and the mGCL + IPL, may increase the accuracy of clinical research on NTG.

Short-term effects of acupuncture on open-angle glaucoma in retrobulbar circulation: additional therapy to standard medication.

Background. The relation between glaucoma and retrobulbar circulation in the prognosis has been indicated. Purpose. To investigate the effects of acupuncture on retrobulbar circulation in open-angle glaucoma (OAG) patients. Methods. Eleven OAG patients (20 eyes with OAG) who were treated by topical antiglaucoma medications for at least 3 months were enrolled. Acupuncture was performed once at acupoints BL2, M-HN9, ST2, ST36, SP6, KI3, LR3, GB20, BL18, and BL23 bilaterally. Retrobulbar circulation was measured with color Doppler imaging, and intraocular pressure (IOP) was also measured at rest and one hour after rest or before and after acupuncture. Results. The Δ value of the resistive index in the short posterior ciliary artery (P < .01) and the Δ value of IOP (P < .01) were decreased significantly by acupuncture compared with no acupuncture treatment. Conclusions. Acupuncture can improve the retrobulbar circulation and IOP, which may indicate the efficacy of acupuncture for OAG.