Eun Ji Lee

Peripapillary retinal nerve fibre layer thickness profile in subjects with myopia measured using the Stratus optical coherence tomography.

Background/aims: To evaluate the relationship between the axial length and refractive error and peripapillary retinal nerve fibre layer (RNFL) thickness profiles measured using Stratus optical coherence tomography (OCT) in subjects with myopia. Methods: Forty-eight eyes of 48 myopic subjects were recruited and divided into three groups according to their spherical equivalent (SE): low myopia (−3.0 D<SE<0.0 D), moderate myopia (−6.0 D<SE⩽−3.0 D) and high myopia (SE⩽−6.0 D) groups. All individuals underwent the imaging with the Stratus OCT. The RNFL thickness profiles were compared between the groups. Results: The global average RNFL was significantly thinner in the high myopia group than in the low myopia group (107.4 (SD 7.6) vs 115.8 (8.5) μm, pu200a=u200a0.029 by post hoc test). For quadrant measures, the RNFL was thicker in the low myopia group than in the moderate and/or high myopia groups for the superior, nasal and inferior quadrants (all p values⩽0.020). However, the temporal quadrant was thinner in the low myopia group than in the moderate and high myopia groups (pu200a=u200a0.001). Conclusion: High myopes had thinner RNFLs than did low myopes and showed different topographic profiles. Although the high myopes had significantly thinner RNFLs in the non-temporal sectors compared with the low myopes, they showed a significantly thicker RNFL in the temporal quadrant.

Reversal of Lamina Cribrosa Displacement after Intraocular Pressure Reduction in Open-Angle Glaucoma

PURPOSEnTo compare the change in lamina cribrosa (LC) displacement in response to intraocular pressure (IOP) lowering in patients with open-angle glaucoma (OAG) using spectral-domain optical coherence tomography (SD-OCT).nnnDESIGNnObservational case series.nnnPARTICIPANTSnOne hundred eyes of 100 patients with OAG in whom IOP at the follow-up examination had decreased by at least 20% compared with the baseline IOP.nnnMETHODSnSerial horizontal B-scan images of the optic nerve head (ONH) were obtained from each eye using enhanced depth imaging SD-OCT. Approximately 65 B-scans covering the optic discs were obtained before and 3 to 6 months after lowering IOP. The baseline and follow-up LC depths (the distance from the Bruchs membrane opening plane to the level of the anterior LC surface) were measured in B-scan images from each eye.nnnMAIN OUTCOME MEASURESnThe mean and maximum amount of reductions in LC depth measured in the 7 selected B-scan images.nnnRESULTSnIntraocular pressure decreased from 21.2±9.1 to 10.5±2.6 mmHg. The percent of IOP reduction was significantly related to the untreated IOP (P < 0.001). There was a significant decrease in the LC depth at the follow-up examination compared with the baseline value (P < 0.001). The magnitude of LC depth reduction was significantly associated with younger age, higher untreated IOP, higher baseline IOP, and greater percent of IOP reduction (all P < 0.02).nnnCONCLUSIONSnReversal of the LC displacement was observed after IOP-lowering treatment in OAG. The degree of LC displacement reversal was related to the amount of IOP lowering.

Microstructure of β-Zone Parapapillary Atrophy and Rate of Retinal Nerve Fiber Layer Thinning in Primary Open-Angle Glaucoma

OBJECTIVEnTo investigate whether the rate of retinal nerve fiber layer (RNFL) thinning differs according to the microstructure of β-zone parapapillary atrophy (PPA) as evaluated by spectral-domain (SD) optical coherence tomography (OCT) in primary open-angle glaucoma (POAG).nnnDESIGNnProspective, observational, comparative study.nnnPARTICIPANTSnA total of 195 eyes with POAG that had been evaluated by serial SD-OCT RNFL thickness measurements for ≥ 2 years.nnnMETHODSnOn the basis of the extent of Bruchs membrane (BM) within the β-zone PPA (area without retinal pigment epithelium [RPE]), as shown in the infrared fundus images, PPA was divided into PPA+BM (PPA with intact BM) and PPA-BM (PPA devoid of BM). Eyes were categorized into group A (having PPA+BM only, n=64), group B (having both PPA+BM and PPA-BM, n=58), group C (having PPA-BM only, n=32), and group D (without β-zone PPA, n=41). The rate of progressive OCT RNFL thinning was determined by linear regression and compared between groups. Factors influencing the rate of RNFL thinning were evaluated, including age, sex, follow-up duration, history of filtering surgery, baseline RNFL thickness, baseline intraocular pressure (IOP), mean IOP and IOP fluctuation during follow-up, PPA types, baseline PPA width, PPA width increase, axial length (AXL), central corneal thickness, and visual field mean deviation (MD).nnnMAIN OUTCOME MEASURESnRate of thinning of OCT RNFL thicknesses over time.nnnRESULTSnPatients in groups B and C were significantly younger and more myopic, and had a greater AXL, than those in groups A and D (all P<0.001). The rate of global RNFL thinning was significantly faster in group A (-1.66 ± 2.94 μm/year) than in the other groups (group B, -0.87 ± 1.28 μm/year; group C, 0.20 ± 1.86 μm/year; group D, -0.28 ± 1.74 μm/year; P = 0.001). Multivariate regression showed a significant association of shorter follow-up period (P = 0.016), greater baseline global RNFL thickness (P = 0.035), type of β-zone PPA (group A, P = 0.023), and greater baseline PPA+BM width (P = 0.034) with a faster rate of RNFL thinning.nnnCONCLUSIONSnThe rate of RNFL thinning differed according to the microstructure of β-zone PPA. It was faster for eyes with β-zone PPA with intact BM than for eyes without β-zone PPA or with β-zone PPA devoid of BM.

Differentiation of Parapapillary Atrophy Using Spectral-Domain Optical Coherence Tomography

PURPOSEnTo develop a classification of parapapillary atrophy (PPA) based on its relationship with the location of Bruchs membrane (BM) termination in primary open-angle glaucoma (POAG) patients.nnnDESIGNnCross-sectional observational study.nnnPARTICIPANTSnThis study analyzed 161 eyes from 161 POAG patients who had temporal β-zone PPA, the width of which was more than 200 μm on at least 1 horizontal scan image obtained by spectral-domain optical coherence tomography within the mid horizontal one third of the optic nerve.nnnMETHODSnBased on the extent of BM within the PPA area, eyes were categorized as group A (intact BM; 76 eyes), group B (discontinuous BM; 65 eyes), and group C (lacking BM; 20 eyes). Differences in the demographic, clinical, and ocular characteristics were compared using analysis of variance and chi-square tests among the 3 groups. The distance from the temporal optic disc margin to the temporal margin of the β-zone PPA (PPA width) and to the edge of the BM (width of PPA without BM [PPA-BM]) were measured on 3 horizontal scans within the mid horizontal one third of the optic nerve, and the averages of the measured values were analyzed. The configuration of the border tissue of Elschnig at the temporal disc margin was assessed.nnnMAIN OUTCOME MEASURESnFactors and configuration of the border tissue of Elschnig associated with each PPA type.nnnRESULTSnThe mean age of group A was significantly higher than that of groups of B and C (P<0.001). The mean axial length was greatest in group C (group C>group B>group A; P<0.001). In group A, the border tissue mainly had a nonoblique configuration (49/76 eyes; 64.5%), whereas most of the eyes in group B (59/65 eyes; 90.8%) and all eyes in group C (20 eyes) it had an externally oblique configuration (P<0.001). A longer axial length was correlated significantly with a larger PPA-BM width (r = 0.478; P<0.001).nnnCONCLUSIONSnA morphologic classification of PPA, which may reflect differing pathogenesis among the groups, is proposed. Parapapillary atrophy with intact BM may be an age-related atrophic change, whereas PPA lacking BM may result from scleral stretching associated with elongation of the globe.nnnFINANCIAL DISCLOSURE(S)nProprietary or commercial disclosure may be found after the references.

Recent Structural Alteration of the Peripheral Lamina Cribrosa Near the Location of Disc Hemorrhage in Glaucoma

PURPOSEnWe investigated whether disc hemorrhage (DH) is associated with the recent structural alteration of the peripheral lamina cribrosa (LC) as assessed by enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT).nnnMETHODSnSerial horizontal B-scan images were obtained by EDI SD-OCT from primary open-angle glaucoma (POAG) patients before and after the detection of DH (DH group, n = 45), and those who had no DH during the 1-year scan interval (non-DH group, n = 36). The images were processed using compensation and contrast enhancement. Then, 11 radial OCT images centered on the optic disc were generated from the 3-dimensionally reconstructed volume image. A recent structural alteration of the LC was defined when either the outward deformation of the anterior LC surface or radial disruption of the LC was identified in the temporal periphery.nnnRESULTSnA recent structural alteration of the LC was found in 40 (88.9%) eyes in the DH group versus 4 (11.1%) eyes in the non-DH group. The amount of maximum outward deformation (55.82 ± 34.60 vs. 20.15 ± 4.28 μm) and radial disruption (69.87 ± 46.74 vs. 18.31 ± 1.17 μm) was larger in the DH group than in the non-DH group. The maximum LC alteration was observed within 1 clock-hour distance from the location of DH in all 40 eyes.nnnCONCLUSIONSnThe peripheral LC exhibited a recent alteration in eyes with DH. The alteration was correlated spatially with the location of the DH. These findings suggest that DH may result from microvascular damage incurred from alteration of the LC near its insertion.

Influence of lamina cribrosa thickness and depth on the rate of progressive retinal nerve fiber layer thinning.

OBJECTIVEnTo determine whether lamina cribrosa (LC) depth (LCD) and LC thickness (LCT) are associated with a faster rate of progressive retinal nerve fiber layer (RNFL) thinning in primary open-angle glaucoma (POAG).nnnDESIGNnProspective, observational study.nnnPARTICIPANTSnOne hundred ten eyes diagnosed with POAG (n = 110 patients) in which RNFL thickness had been measured by serial spectral-domain (SD) optical coherence tomography (OCT) for at least 2.5 years.nnnMETHODSnThe participants underwent enhanced depth imaging volume scanning of the optic nerve, and circumpapillary RNFL thickness measurements were obtained using SD OCT. The participants were followed up regularly with serial RNFL thickness measurements at 6-month or longer intervals. Lamina cribrosa depth was measured at 7 equidistant planes and LCT was measured at 3 locations (superior midperipheral, midhorizontal, and inferior midperipheral). The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements over time.nnnMAIN OUTCOME MEASURESnFactors associated with the rate of OCT RNFL thinning.nnnRESULTSnA faster rate of RNFL thinning was associated with disc hemorrhage during follow-up (P < 0.001), wider β-zone parapapillary atrophy with Bruchs membrane (P = 0.037), larger global RNFL thickness (P = 0.026), larger LCD (P < 0.001), and smaller LCT (P = 0.002). The association between LCD and the rate of RNFL thinning was explained better using a fractional polynomial model (R(2) = 0.223) than a linear model (R(2) = 0.134; P = 0.010). Davies test revealed a statistically significant breakpoint for LCD (489.7 μm), above which a faster rate of global RNFL thinning was associated with a larger LCD.nnnCONCLUSIONSnA thinner LC and a larger LC displacement had a significant influence on the rate of progressive RNFL thinning.

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

PurposenThe 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.nnnMethodsnThe 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.nnnResultsnThe 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.nnnConclusionsnDecreased 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.

Improved Reproducibility in Measuring the Laminar Thickness on Enhanced Depth Imaging SD-OCT Images Using Maximum Intensity Projection

PURPOSEnTo investigate whether the thin-slab maximum intensity projection (MIP) image improves the reproducibility of the measurement of spectral domain optical coherence tomography (SD-OCT) based lamina cribrosa thickness (LCT).nnnMETHODSnOptic discs of 63 open angle glaucoma patients or glaucoma suspects were scanned with enhanced depth imaging spectral domain optical coherence tomography (SD-OCT). The B-scan images were constructed three-dimensionally using maximum intensity projection (MIP). The whole mip volume was then cut into thin slabs of two scan-line distance width (approximately 64 μm) at three 3 locations: mid-horizontal, and superior and inferior mid-peripheral regions of the optic nerve head. The LCT was measured in the thin-slab MIP images (LCT-MIP) and the three B-scans corresponding to each thin-slab MIP image (LCT-Bscan) at the three regions in each eye. The interobserver and intraobserver reproducibility of measuring the LCT-MIP and LCT-Bscan were evaluated by calculating the intraclass correlation coefficient (ICC), coefficient of variation (CV), and coefficient of repeatability (CR). The agreement between the LCT-MIP and the LCT-Bscan was assessed by Bland-Altman analysis.nnnRESULTSnThe thin-slab MIP images provided better image contrast with more distinct borders of the lamina cribrosa compared to the B-scan images. Both intraobserver and interobserver ICCs were higher for LCT-MIP than for LCT-Bscan in all areas. The 95% limit of agreement of measurement differences between LCT-Bscan and LCT-MIP ranged from -29.43 to 32.55 μm.nnnCONCLUSIONSnThe thin-slab MIP images provided a higher reproducibility in measuring the LCT using SD-OCT than the B-scan images. With thin-slab MIP images, the detection of the laminar borders was more straightforward. This technique should facilitate the evaluation of the lamina cribrosa.

Lamina Cribrosa Configuration in Tilted Optic Discs With Different Tilt Axes: A New Hypothesis Regarding Optic Disc Tilt and Torsion

PURPOSEnTo determine the configuration of the anterior lamina cribrosa (LC) surface in eyes with different tilt axes.nnnMETHODSnA total of 114 eyes (66 glaucomatous eyes and 48 healthy eyes) with tilted optic discs (ovality index > 1.3) were divided into vertical- and horizontal-tilt groups according to their optic disc tilt axis. Serial horizontal B-scan images of the ONH were obtained from each eye using enhanced-depth imaging spectral-domain optical coherence tomography. After three-dimensional reconstruction of the images, the anterior LC surface depth (LCD) was measured in each of the oblique scans containing the long disc axis and in the seven horizontal B-scans that divided the anterior LC surface vertically into eight parts.nnnRESULTSnThe configuration of the anterior LC surface along the long disc axis differed markedly between groups. The vertical-tilt group had a larger LCD at superior locations than at inferior locations, while the pattern was the opposite in the horizontal-tilt group. The RNFL thinning in glaucomatous eyes was most prominent at both the superotemporal and inferotemporal sectors in the vertical-tilt group, while it was predominated at the inferotemporal sector in the horizontal-tilt group.nnnCONCLUSIONSnThe configuration of the anterior LC surface in eyes with differed optic disc tilt axis suggested that the horizontally-tilted optic discs may not be resulted from the optic disc rotation, but from the optic disc tilt centered on the oblique axis. The preferential location of RNFL thinning could be explained by the LCD profile differing according to the tilt axis.

Variation of Lamina Cribrosa Depth Following Trabeculectomy

PURPOSEnTo investigate the long-term changes in lamina cribrosa (LC) depth following trabeculectomy.nnnMETHODSnSerial horizontal B-scan images of the optic nerve head were obtained using spectral-domain optical coherence tomography from 28 primary open-angle glaucoma patients who underwent trabeculectomy and were followed up for at least 2 years. Approximately 65 B-scans covering the optic discs were obtained before surgery and at 6 months and ≥2 years postoperatively. The pre- and postoperative LC depth (the distance from the opening plane of Bruchs membrane to the level of the anterior LC surface) was determined on seven selected B-scan images from each eye and averaged (mean LC depth).nnnRESULTSnThe intraocular pressure (IOP) decreased from 27.4 ± 9.0 (mean ± SD) to 9.7 ± 3.1 mm Hg at postoperative 6 months (P < 0.001) and subsequently increased to 12.7 ± 5.1 mm Hg at a mean final follow-up of 27.1 ± 3.3 months (P = 0.001). The mean LC depth was reduced from 625.6 ± 186.3 to 499.6 ± 140.6 μm at postoperative 6 months (P < 0.001). A subsequent slight, but nonsignificant, increase in the LC depth was noted at final follow-up. The degree of LC depth increase after 6 months was significantly associated with younger age, higher IOP at final follow-up, greater IOP fluctuation, and higher mean follow-up IOP from 6 months to final follow-up (all P < 0.05).nnnCONCLUSIONSnThe postoperative reduction in the LC depth that was observed 6 months after surgery was not maintained in some eyes. The redisplacement of the LC after postoperative 6 months appeared more likely to occur in patients who were younger and who had higher IOP and IOP fluctuation during the postoperative follow-up.