Influence of choroidal microvasculature dropout on progressive retinal nerve fibre layer thinning in primary open-angle glaucoma: comparison of parapapillary ß-zones and γ-zones.

BACKGROUND/AIMS: To compare the influence of choroidal microvasculature dropout (cMvD) on progressive retinal nerve fibre layer (RNFL) thinning in glaucomatous eyes with parapapillary ß-zones and γ-zones. METHODS: 294 eyes with primary open-angle glaucoma (POAG) and parapapillary atrophy (PPA) underwent optical coherence tomography (OCT) to determine the type of PPA and OCT angiography scanning of the optic nerve head to determine the presence of cMvD. Eyes were classified based on the type of PPA (ß-zones and γ-zones), and their clinical characteristics were compared. Factors associated with the rate of rapid progressive RNFL thinning were determined in each group, including the presence of cMvD as an independent variable. RESULTS: Of the 294 eyes, 186 and 108 were classified as having ß-zones and γ-zones, respectively. The rate of RNFL thinning was slower (p<0.001), axial length was longer (p<0.001) and presence of cMvD was less frequent (57.4% vs 73.1%, p=0.006) in eyes with γ-zone than those with ß-zone. Multivariate analyses showed that greater lamina cribrosa curvature (p=0.047) and the presence of cMvD (p=0.010) were associated with a faster rate of RNFL thinning in eyes with ß-zone, whereas larger intraocular pressure fluctuation (p<0.001), shorter axial length (p=0.042) and greater baseline RNFL thickness (p<0.001) were associated with a faster rate of RNFL thinning in eyes with γ-zone. CONCLUSIONS: The presence of cMvD was significantly associated with a faster rate of RNFL thinning in POAG eyes with ß-zone, but not γ-zone. The pathogenic consequences of cMvD in POAG eyes may depend on accompanying peripapillary structures.

Actual anterior-posterior corneal radius ratio in eyes with prior myopic laser vision correction according to axial length.

We retrospectively evaluate the actual anterior-posterior (AP) corneal radius ratio in eyes with previous laser correction for myopia (M-LVC) according to axial length (AL) using biometry data exported from swept-source optical coherence tomography between January 2018 and October 2021 in a tertiary hospital (1018 eyes with a history of M-LVC and 19,841 control eyes). The AP ratio was significantly higher in the LVC group than in the control group. Further, it was significantly positively correlated with AL in the LVC group. We also investigated the impact of the AP ratio, AL and keratometry (K) on the absolute prediction error (APE) in 39 eyes that underwent cataract surgery after M-LVC. In linear regression analyses, there were significant correlations between APE and AL/TK, while APE and AP ratio had no correlation. The APE was significantly lower in the Barrett True-K with total keratometry (Barrett True-TK) than in the Haigis-L formula on eyes with AL above 26 mm and K between 38 and 40 D. In conclusion, in eyes with previous M-LVC, AP ratio increases with AL. The Barrett True-K or Barrett True-TK formulas are recommended rather than Haigis-L formula in M-LVC eyes with AL above 26 mm and K between 38 and 40D.

Choroidal detachment and hypotony following selective laser trabeculoplasty: a case report.

BACKGROUND: Selective laser trabeculoplasty (SLT) is relatively safe and effective in lowering intraocular pressure (IOP). However, although rare, complications can occur after SLT. This report describes a patient with choroidal detachment due to hypotony following SLT without anterior chamber (AC) inflammation. CASE PRESENTATION: A 67-year-old man was referred for elevated IOP in his left eye with advanced glaucomatous visual field loss. He had previously been diagnosed with idiopathic uveitic glaucoma in the left eye, for which he underwent laser iridotomy, trabeculectomy, and cataract surgery. At the first visit, the IOP of his left eye measured by Goldmann tonometry was 28 mmHg despite maximally tolerated medical treatment. SLT was performed in his left eye, resulting in an IOP of 7 mmHg 7 days later. At 3 weeks post-procedure, the patient experienced ocular pain and decreased visual acuity in his left eye. Slit-lamp examination revealed deep anterior chamber depth and no inflammation reaction, but the IOP in his left eye was 4 mmHg, and both fundus and B-scan ultrasonography showed serous choroidal detachment. All anti-glaucoma agents were stopped, and the patient was started on treatment with oral prednisolone and cyclopentolate eye drops. Three weeks later, choroidal detachment had resolved and the IOP in his left eye had stabilized at 8 mmHg. Follow-up 3 months later showed that the IOP in his left eye remained stable. CONCLUSIONS: Choroidal detachment-related hypotony is a rare complication of SLT. This possible complication following SLT should be informed to the patients and considered when performing the procedure.

Reply to Wostyn, P. Could Young Cerebrospinal Fluid Combat Glaucoma? Comment on "Lee et al. Association between Optic Nerve Sheath Diameter and Lamina Cribrosa Morphology in Normal-Tension Glaucoma. J. Clin. Med. 2023, 12, 360".

We are pleased to see that Peter Wostyn has contributed a Comment: "Could Young Cerebrospinal Fluid Combat Glaucoma?" [...].

Discrepancy between peripapillary retinal and choroidal microvasculature and the rate of localized retinal nerve fiber layer thinning in glaucoma.

This observational case series study is conducted to compare the extent of microvasculature impairment in the peripapillary retina and choroid in eyes with primary open-angle glaucoma (POAG), and to investigate the association of the discrepancy between the microvasculature impairments of each layer with the rate of progressive retinal nerve fiber layer (RNFL) thinning. A total of 88 POAG eyes with a localized RNFL defect were enrolled, including 67 eyes with and 21 eyes without choroidal microvasculature dropout (CMvD). Circumferential widths of retinal microvascular impairment (RMvI) and CMvD were measured, and eyes were classified based on the relative width of CMvD to RMvI (CMvD/RMvI ratio). The rate of RNFL thinning was determined by linear regression based on ≥ 5 serial OCT examinations. Thinner global RNFL and worse visual field mean deviation at baseline were associated with a larger circumferential width of the RMvI, whereas the presence of cold extremities, lower mean arterial pressure and thinner juxtapapillary choroid were associated with a larger circumferential width of the CMvD. The rate of global RNFL thinning was faster in eyes with larger relative CMvD width than in eyes with equal CMvD and RMvI widths and in eyes without CMvD (P = 0.001). Lower mean arterial pressure (P = 0.041), larger CMvD width (P = 0.046), larger CMvD/RMvI ratio (P = 0.041), and detection of disc hemorrhage during the follow-up (P = 0.013) were significant factors associated with faster global RNFL thinning. Larger CMvD width relative to RMvI width may be indicative of an increased risk of faster RNFL thinning in POAG with localized RNFL defect. Comparing the microvasculature impairment in individual layers may help predict more rapid glaucoma progression.

Choroidal Microvasculature Dropout in the Absence of Parapapillary Atrophy in POAG.

Purpose: To describe the parapapillary choroidal microvasculature dropout (CMvD) in glaucomatous eyes without ß-zone parapapillary atrophy (ß-PPA) and compare its characteristics with that of CMvD with ß-PPA. Methods: Peripapillary choroidal microvasculature was evaluated on en face images obtained using optical coherence tomography angiography. CMvD was defined as a focal sectoral capillary dropout with no visible microvascular network identified in the choroidal layer. Peripapillary and optic nerve head structures, including the presence of ß-PPA, peripapillary choroidal thickness and lamina cribrosa curvature index were evaluated using the images obtained by enhanced depth-imaging optical coherence tomography. Results: The study included 100 glaucomatous eyes with CMvD (25 without and 75 with ß-PPA) and 97 eyes without CMvD (57 without and 40 with ß-PPA). Regardless of the presence of ß-PPA, eyes with CMvD tended to have a worse visual field at a given RNFL thickness than eyes without CMvD, with patients having eyes with CMvD having lower diastolic blood pressure and more frequent cold extremities than patients with eyes lacking CMvD. Peripapillary choroidal thickness was significantly smaller in eyes with than without CMvD, but was not affected by the presence of ß-PPA. ß-PPA without CMvD was not associated with vascular variables. Conclusions: CMvD were found in the absence of ß-PPA in glaucomatous eyes. CMvDs had similar characteristics in the presence and absence of ß-PPA. Clinical and optic nerve head structural characteristics potentially relevant to compromised optic nerve head perfusion were dependent on the presence of CMvD, rather than the presence of ß-PPA.

Association between Optic Nerve Sheath Diameter and Lamina Cribrosa Morphology in Normal-Tension Glaucoma.

(1) Background: To compare optic nerve sheath diameter (ONSD) in normal-tension glaucoma (NTG) and healthy eyes and to investigate the association between ONSD and lamina cribrosa (LC) morphology. (2) Methods: This cross-sectional study included 69 NTG eyes and 69 healthy eyes matched for age, axial length, and intraocular pressure. The LC curvature index (LCCI) was measured from horizontal Cirrus HD-OCT B-scan images from five uniformly divided positions vertically of the optic nerve. The average LCCI was defined as the mean of the measurements at these five locations. ONSD was measured as the width of the optic nerve sheath at the site perpendicular 3 mm behind the posterior globe. LCCI and ONSD were compared in eyes with NTG and healthy eyes. The clinical factors that could affect LCCI were analyzed. (3) Results: NTG eyes had significantly smaller mean ONSD (4.55 ± 0.69 mm vs. 4.97 ± 0.58 mm, p < 0.001) and larger average LCCI (11.61 ± 1.43 vs. 7.58 ± 0.90, p < 0.001) than matched healthy control eyes. LCCI was significantly correlated with smaller ONSD, higher intraocular pressure, thinner global retinal nerve fiber thickness, and worse visual field loss in all subjects (all Ps ≤ 0.022). (4) Conclusions: NTG eyes had smaller ONSD and greater LCCI than healthy control eyes. In addition, a negative correlation was observed between ONSD and LCCI. These findings suggest that cerebrospinal fluid pressure, which ONSD indirectly predicts, may affect LC configuration. Changes in the retrolaminar compartment may play a role in glaucoma pathogenesis.

Predictive Modeling of Long-Term Glaucoma Progression Based on Initial Ophthalmic Data and Optic Nerve Head Characteristics.

Purpose: The purpose of this study was to develop a model, based on initial optic nerve head (ONH) characteristics, predictive of long-term rapid retinal nerve fiber layer (RNFL) thinning in patients with open-angle glaucoma (OAG). Methods: This study evaluated 712 eyes with OAG that had been followed up for >5 years with annual evaluation of RNFL thickness. Baseline ophthalmic features were incorporated into the machine learning models for prediction of faster RNFL thinning. The model was trained and tested using a random forest (RF) method, and was interpreted using Shapley additive explanations. Factors associated with faster rate of RNFL thinning were statistically evaluated using a decision tree. Results: The RF model showed that greater lamina cribrosa (LC) curvature, higher intraocular pressure (IOP), visual field mean deviation converging towards -5 dB, and thinner peripapillary choroid at baseline were the four most significant features predicting faster RNFL thinning. Partial interaction between the features showed that larger LC curvature was a strong factor for faster RNFL thinning when it exceeded approximately 12.0. When the LC curvature was ≤12, higher initial IOP and thinner peripapillary choroid played a role in the rapid RNFL thinning. Based on the decision tree, higher IOP (>26.5 mm Hg), greater laminar curvature (>13.95), and thinner peripapillary choroid (≤117.5 µm) were the 3 most important determinants affecting the rate of RNFL thinning. Conclusions: Baseline ophthalmic data and ONH characteristics of patients with OAG were predictive of eyes at risk of faster progression. Combinations of important characteristics, such as IOP, LC curvature, and choroidal thickness, could stratify eyes into groups with different rates of RNFL thinning. Translational Relevance: This work lays the foundations for developing prediction models to estimate glaucoma prognosis based on initial ONH characteristics.

Morphologic Changes in the Lamina Cribrosa Upon Intraocular Pressure Lowering in Patients With Normal Tension Glaucoma.

Purpose: The purpose of this study was to investigate whether the lamina cribrosa (LC) curve changes in response to intraocular pressure (IOP) reduction following administration of topical ocular hypotensive eye drops in eyes with normal tension glaucoma (NTG). Methods: Ninety-three eyes of 93 patients with treatment naïve NTG at initial examination and with ≥20% reduction from baseline IOP following administration of topical ocular hypotensive eye drops were included. Serial horizontal B-scan images of the optic nerve head (ONH) were obtained from each eye using enhanced depth imaging spectral domain optical coherence tomography (OCT) before and 1 year after IOP-lowering treatment. The LC curvature in each eye was assessed by measuring the LC curvature index (LCCI) in horizontal OCT B-scan images obtained at three (superior, central, and inferior) locations spaced equidistantly across the vertical optic disc diameter before and after IOP-lowering treatment. We evaluated the OCT detectible change in the LC curvature based on the interval change of LCCI to exceed the intersession standard deviation of 1.96 times and factors associated with the magnitude of the LCCI change in the eyes showing significant LC change. Results: IOP decreased from 15.7 ± 2.5 mm Hg at baseline to 11.2 ± 1.7 mm Hg after topical glaucoma medication. Among the 93 subjects, 62 (66.7%) eyes showed the significant reduction of the LCCI (interssetional change over 1.5) after the treatment; greater interssessional change of the LCCI after IOP reduction was associated with younger age (P = 0.020) and larger baseline LCCI (P < 0.001). Conclusions: The OCT detectible changes in LC curvature occurred in response to a modest decrease in the IOP in the naïve NTG eyes. The therapeutic benefit of these changes need to be assessed in longitudinal studies.

Cognitive Impairment and Lamina Cribrosa Thickness in Primary Open-Angle Glaucoma.

Purpose: The purpose of this study was to investigate the relationship between the lamina cribrosa (LC) thickness (LCT) as assessed using enhanced depth-imaging (EDI) optical coherence tomography (OCT) and cognitive function in primary open-angle glaucoma (POAG). Methods: The study consisted of 105 POAG eyes and 23 nonglaucomatous control eyes that completed neuropsychological tests. The optic nerve heads of the patients were imaged using EDI-OCT. B-scan images were constructed in three dimensions using maximum intensity projection (MIP), and the LCT was measured using the thin-slab MIP images. A comprehensive battery consisting of 15 neuropsychological tests was used to evaluate cognitive function. Results: POAG eyes had smaller mean LCT as compared with control eyes (P < 0.001). Age and Mini Mental State Examination (MMSE) scores did not differ between the two groups. Linear regression analysis revealed that lower scores on the MMSE (P < 0.001), presence of glaucoma (P = 0.006), and a smaller global retinal nerve fiber layer thickness (P < 0.001) were independently associated with a smaller mean LCT. Davies' test revealed a statistically significant breakpoint for the mean LCT (221.14 µm), below which a smaller MMSE score was significantly associated with a smaller mean LCT. In POAG eyes with a mean LCT smaller than the breakpoint (< 221.14 µm), not only the global cognition but also the visuospatial function and visual memory were worse than in those with a larger mean LCT (all P ≤ 0.003). Conclusions: Impairment of cognitive function was observed in patients with POAG with a thinner LC. The role of LC imaging as a potential biomarker to monitor cognitive impairment needs further investigation. Translational Relevance: LC thinning may reflect a shared mechanism of neurodegenerative diseases in the brain and optic nerve.

Lamina Cribrosa Moves Anteriorly After Trabeculectomy in Myopic Eyes.

Purpose: The purpose of this study was to investigate changes in lamina cribrosa (LC) depth after trabeculectomy in myopic eyes using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). Methods: Serial horizontal B-scans of the optic nerve head of 41 myopic eyes with primary open-angle glaucoma (POAG) were obtained before and 3 months after trabeculectomy using EDI SD-OCT. LC depth, defined as the distance from the opening plane of Bruch's membrane to the level of the anterior LC surface, was measured before and 3 months after trabeculectomy at 7 locations spaced equidistantly across the vertical optic disc diameter on B-scan images. The mean of the measurements at these seven planes was defined as the average LC depth. Factors associated with changes in LC depth were identified by linear regression. Results: Intraocular pressure (IOP) decreased from 26.3 ± 9.3 millimeters of mercury (mm Hg) preoperatively to 10.6 ± 3.5 mm Hg 3 months after trabeculectomy. LC depth was significantly lower 3 months after trabeculectomy than preoperatively (P < 0.001, all planes). The magnitude of LC depth reduction was significantly associated with younger age, higher preoperative LC depth, and greater magnitude of IOP reduction (all P ≤ 0.016). Conclusions: LC depth reduction was observed after trabeculectomy in myopic eyes. The degree of LC depth reduction was not related to the degree of myopia.

Focal lamina cribrosa defects are not associated with steep lamina cribrosa curvature but with choroidal microvascular dropout.

Focal lamina cribrosa (LC) defects have been found to play an important role in the development and progression of glaucomatous optic neuropathy. However, the mechanism of generation of focal LC defects is largely unknown. This cross-sectional study was performed to investigate LC curvature and the frequency of parapapillary choroidal microvascular dropout (MvD) in glaucomatous eyes with focal LC defects. This study was conducted by a retrospective review of patients with primary open-angle glaucoma (POAG) included in an ongoing prospective study being performed at the Seoul National University Bundang Hospital (Investigating Glaucoma Progression Study). A total of 118 eyes of 118 patients with POAG, 59 with and 59 without focal LC defects, with eyes matched by age, axial length, and severity of visual field (VF) damage were included. Posterior LC bowing was assessed by calculating LC curvature index (LCCI), as the inflection of a curve representing a section of the LC, on the optic nerve head images obtained by enhanced-depth-imaging (EDI) spectral-domain optical coherence tomography (OCT). MvD was detected by OCT angiography. LCCI and MvD frequency were compared between eyes with and without focal LC defects. Mean LCCI was significantly smaller than in eyes with than without focal LC defects (9.75 ± 1.29 vs. 11.25 ± 1.39, P < 0.001). MvD was significantly more frequent in eyes with than without focal LC defects (84.7% vs. 49.2%, P < 0.001). MvD in eyes with focal LC defects showed a strong topographic correlation with the focal LC defects. These findings suggest that focal LC defects may primarily result from vascular factors rather than from mechanical strain.

Comparison of vascular-function and structure-function correlations in glaucomatous eyes with high myopia.

BACKGROUND/AIMS: To determine the usefulness of peripapillary retinal vessel density (VD) measured using optical coherence tomography (OCT) angiography (OCTA) in the evaluation of glaucomatous visual field damage in highly myopic eyes with primary open-angle glaucoma (POAG). METHODS: This cross-sectional observational study enrolled a total of 124 myopic POAG eyes consisting of 40 eyes showing a segmentation error (SE) in OCT scans and 84 eyes without an SE. The peripapillary retinal VD, circumpapillary retinal nerve fibre layer thickness (RNFLT) and visual field sensitivity loss (VFSL) were assessed using OCTA, spectral-domain OCT and standard automated perimetry, respectively. The topographical correlations between the VD and VFSL, and between the RNFLT and VFSL were determined in subgroups divided according to the presence of an SE. RESULTS: The peripapillary retinal VD showed significant topographical correlation with VFSL both in the highly myopic POAG eyes without an SE globally (R=0.527, p<0.001), and in temporal (R=0.593), temporal-superior (R=0.543), nasal-inferior (R=0.422) and temporal-inferior sectors (R=0.600, all p<0.001), and in those with an SE globally (R=0.343, p=0.030), and in temporal (R=0.494, p=0.001), temporal-superior (R=0.598, p<0.001), and temporal-inferior sectors (R=0.424, p=0.006). The correlation with VFSL did not differ between the VD and RNFLT in the eyes without an SE CONCLUSION: Peripapillary VD as measured with OCTA showed a topographical correlation with VFSL in highly myopic POAG eyes regardless of the presence of an OCT SE OCTA may be a useful adjunct for evaluating glaucomatous visual field damage in high myopia, where the OCT results are frequently confounding.

Evaluation of Peripapillary Choroidal Microvasculature to Detect Glaucomatous Damage in Eyes With High Myopia.

PRECIS: Parapapillary choroidal microvasculature dropout (MvD), as observed by optical coherence tomography (OCT) angiography, was useful to detect glaucomatous damage in highly myopic eyes with unreliable OCT results due to segmentation errors. PURPOSE: The purpose of this study was to evaluate the usefulness of optical coherence tomography angiography (OCTA) imaging of the peripapillary choroidal microvasculature in detecting glaucomatous damage in highly myopic eyes, in cases where evaluating the thickness of the retinal nerve fiber layer (RNFL) is unreliable due to OCT segmentation errors. MATERIALS AND METHODS: Forty-five highly myopic eyes with primary open-angle glaucoma (POAG) with an axial length >26.5 mm, and 15 age-matched and axial length-matched 15 control eyes were included in this cross-sectional observational study. All participants had a segmentation error in OCT circumpapillary RNFL scanning. The peripapillary choroidal microvasculature was evaluated on en-face images obtained using swept-source OCTA. MvD was defined as a focal sectoral capillary dropout with no visible microvascular network identified in the choroidal layer. The topographic correlation between the MvD and a hemifield visual field (VF) defect was assessed using κ statistics. The MvD size was assessed by measuring both its area and circumferential extent. RESULTS: Choroidal MvD was observed in 44 of the 45 (97.8%) POAG eyes with high myopia, while none of the control eyes showed a choroidal MvD. There was an excellent topographic relationship between the choroidal MvD and the hemifield VF defect (κ=0.863, P<0.001). The area (R=0.2619, P=0.0006) and circumferential extent (R=0.3088, P=0.0002) of the MvD have significantly associated with the VF mean deviation. CONCLUSIONS: Choroidal MvDs were observed in most of the highly myopic POAG eyes and were topographically correlated with the location of glaucomatous VF defects despite unreliable OCT RNFL thickness measurements. Using OCTA to investigate the choroidal microvasculature may facilitate diagnoses of glaucoma in highly myopic eyes.

Lamina Cribrosa Curvature in Healthy Korean Eyes.

Given that posterior bowing of the lamina cribrosa (LC) is a principle event in the development of glaucomatous damage, assessment of the LC morphology may have clinical utility in diagnosing and managing glaucoma patients. LC curvature has been suggested as an index to evaluate the LC morphology. To apply LC morphology in clinical practice, it is necessary to know normal profiles of LC curvature in healthy population. This study was performed to investigate the characteristics of LC curvature in healthy eyes using enhanced depth imaging spectral-domain optical coherence tomography in a total of 250 eyes of 125 healthy Korean subjects. The lamina cribrosa curvature index (LCCI) values at seven locations spaced equidistantly across the vertical optic disc diameter were measured on serial horizontal B-scan images. The mean value of the seven measurements was defined as the average LCCI. The average LCCI was 7.46 ± 1.22 (range, 4.29-10.48) and did not differ significantly between the right and left eyes. There was a strong inter-eye correlation within subjects. LCCI was significantly larger in eyes with shorter axial length (P < 0.001). The observed range of LCCI in healthy subjects may be used as a reference for evaluating LC curvature in glaucomatous eyes.

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.

Comparison between Lamina Cribrosa Depth and Curvature as a Predictor of Progressive Retinal Nerve Fiber Layer Thinning in Primary Open-Angle Glaucoma.

PURPOSE: To compare the ability of lamina cribrosa (LC) depth (LCD) and LC curvature to predict the rate of progressive retinal nerve fiber layer (RNFL) thinning in patients with primary open-angle glaucoma (POAG). DESIGN: Observational case series. PARTICIPANTS: A total of 114 eyes of 114 patients diagnosed with POAG, in which RNFL thickness had been measured by serial spectral-domain (SD) OCT for at least 2.5 years. METHODS: The optic nerves of all participants underwent enhanced depth imaging volume scanning, and their circumpapillary RNFL thickness was measured using SD OCT, followed by regular serial measurements of RNFL thickness at intervals of ≥6 months. The LCD from the levels of Bruch's membrane (BM, LCD-BM) and the anterior sclera (AS, LCD-AS), and LC curvature index (LCCI) were measured by SD OCT at 3 locations: superior midperipheral, midhorizontal, and inferior midperipheral. The rate of RNFL thinning over time was determined by linear regression of serial OCT measurements of RNFL thickness. MAIN OUTCOME MEASURES: Factors associated with the rate of OCT RNFL thinning. RESULTS: Univariate analysis showed that larger LCD-BM (P = 0.001), LCD-AS (P < 0.001), and LCCI (P < 0.001) were all significantly associated with a faster rate of global RNFL thinning. The LCCI showed a stronger correlation with the rate of global RNFL thinning than LCD-BM (P < 0.001) or LCD-AS (P < 0.001). Of the 3 variables, only LCCI remained significant on multivariate analysis (P < 0.001). Disc hemorrhage during follow-up (P = 0.003), wider parapapillary atrophy ß-zone (P = 0.017), and greater global RNFL thickness (P = 0.040) were also significantly associated with a faster rate of global RNFL thinning. CONCLUSIONS: Morphology of LC was significantly associated with the rate of progressive RNFL thinning. Curvature of LC better predicted progressive RNFL thinning than did LCD measured from the BM or AS.

Topographic correlation between juxtapapillary choroidal thickness and parapapillary deep-layer microvasculature dropout in primary open-angle glaucoma.

PURPOSE: To investigate the topographic relationship between parapapillary deep-layer microvasculature dropout (MvD) as assessed by optical coherence tomography (OCT) angiography (OCTA) and the juxtapapillary choroidal thickness (JPCT) in primary open-angle glaucoma (POAG). METHODS: A total of 194 eyes (138 POAG and 56 control eyes) having parapapillary atrophy (PPA) were imaged using the swept-source OCT and OCTA to examine the microstructure of PPA and measure the JPCT, and to determine the presence of the MvD. MvD was defined as a focal sectoral capillary dropout without any visible microvascular network identified in the parapapillary deep-layer in the en face OCTA images. RESULTS: JPCT was smaller in the POAG group than control group at 6-, 6.5-, 7- and 7.5-o'clock meridians (all p≤0.002). When POAG eyes were classified into those with parapapillary γ-zone and those with only ß-zone without γ-zone, the mean JPCT was significantly smaller in the latter (p=0.027). The JPCT differed between with and without MvD only in eyes with a γ-zone: the JPCT was smaller in the eyes having MvD at 7- and 7.5-o'clock meridians (both p=0.001), where MvD was detected most frequently. However, such a difference was not observed in the eyes with only ß-zone without the γ-zone at any of the meridians. CONCLUSIONS: Localised reductions in JPCT were observed at the location of MvD in POAG eyes with parapapillary γ-zone. Such a correlation was not observed in the POAG eyes with only ß-zone, but the mean JPCT was significantly smaller in this group.

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.

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.