Optic Disc Torsion Research Articles

Anatomic Features of the Lamina Cribrosa and Optic Disc in Ocular Hypertension, Glaucoma and Healthy Eyes.

Central lamina cribrosa thickness (LCT) was found to be higher in eyes with ocular hypertension (OHT) compared with primary open angle glaucoma (POAG) and healthy controls (HCs). To evaluate the anatomic features of lamina cribrosa (LC) and the optic disc (OD) using swept-source optical coherence tomography (OCT) in eyes with OHT. Treatment naive eyes with OHT and POAG and healthy eyes were included. All eyes underwent a complete ophthalmological examination in addition to swept-source OCT of the OD. Anatomic features of LC, including central LCT, LC depth, prelaminar depth (PLD), and prelaminar tissue thickness, were measured manually using the internal caliper function of the OCT device and compared within groups. OD ovality, disc-foveal angle, and OD torsion were measured on colored photographs, using imageJ software. Seventy-one eyes of 37 patients in the OHT group, 41 eyes of 26 patients in the POAG group, and 30 eyes of 30 patients in the HC group were enrolled in the study. Groups were similar in age and sex distribution. Central LCT was significantly higher in the OHT group, compared with HCs (333.8 ± 50.5 vs 304.5 ± 46.3 µm, P = 0.02) and POAG group (286.7 ± 140.4, P = 0.001). PLD and LC depth were both highest in POAG (282.3 ± 145.5 µm and 471.3 ± 195.2 µm), followed by OHT (244.8 ± 30.2 µm and 440.7 ± 18.7 µm) and HCs (170.1 ± 152.6 µm and 412.8 ± 80 µm), only the difference between POAG and HCs in PLD was statistically significant ( P = 0.03). Prelaminar tissue thickness, OD torsion, disc-foveal angle, and disc ovality showed no significant difference. LC was significantly thicker in eyes with OHT, compared with POAG and HCs. This finding may be relevant to optic nerve protection from high intraocular pressure in patients with OHT.

Optic disc tilt and rotation effects on positions of superotemporal and inferotemporal retinal nerve fibre layer peaks in myopic Caucasians

ABSTRACT Clinical relevance In myopic eyes, the optic disc may become tilted and rotated, making glaucoma diagnosis more difficult. Background To determine the presence of tilted optic disc, the degree of optic disc rotation, and their effects on the angular location of superotemporal and inferotemporal retinal nerve fibre layer (RNFL) peaks in healthy myopic Caucasians. Methods Non-glaucomatous healthy myopic Caucasian eyes with an axial length > 24 mm were evaluated. ImageJ was used to quantify optic disc tilt and torsion on red-free fundus photography. The RNFL was scanned using spectral-domain optical coherence tomography. The angle of the superotemporal and inferotemporal peaks with the vertical-horizontal meridian was measured. Results Fifty-four eyes of 54 individuals were evaluated. The axial length was correlated with the angular location for both the superotemporal (r = −0.549, p < 0.001) and inferotemporal (r = −0.415, p = 0.002) RNFL peaks; they were placed more temporally in eyes with higher axial lengths. For each 1 mm increase in axial length, the angle between the superotemporal peak and the temporal horizontal meridian decreased by 3.976°, and the angle between the inferotemporal apex and the temporal horizontal meridian decreased by 3.028°. The angle between the inferotemporal peak and the temporal horizontal meridian decreased by 0.231° for each 1° increase in optical disc torsion (R2 = 0.09 Regression coefficient = −0.231, p = 0.027). Conclusions The temporal shift of superior and inferior peaks, the thickening of temporal and nasal RNFL, the presence of tilted optic disc, and optic disc rotation may cause misinterpretation of the RNFL in myopic Caucasians. When evaluating peripapillary RNFL thickness in myopic individuals, it would be better to consider these to avoid misinterpretation.

Relationship between peripapillary atrophy and myopia progression in the eyes of young school children.

Myopia progression is of great concern because of its association with an increased risk of sight-threatening conditions. This study aims to determine whether certain clinical and optic disc features are associated with the rate of myopia progression. In this retrospective longitudinal observational study, we reviewed the medical records of 95 patients aged 6-11 years with myopia (spherical equivalent refractive error (SER) at baseline ≤ -0.5 D) and collected data regarding medical history, comprehensive ophthalmologic examination, and fundus photography. Using fundus photographs, we measured the ratio of horizontal to vertical disc diameter (HVDR), ratio of maximum β-zone peripapillary atrophy (β-PPA) width to vertical disc diameter (PVDR), and optic disc torsion. Outcome measurements included 2-year myopia progression (D/year) and overall myopia progression during the entire follow-up with a mean of 51 months. Mean age at initial visit was 7.67 ± 1.50 years and mean SER at baseline was -2.91 ± 1.68 D (range, -5.75 to -0.50 D). In the univariate analysis, age, parental myopia, SER at baseline, HVDR, and PVDR were significantly associated with myopia progression (P < 0.05). In the multivariate analysis, however, only age at initial visit and PVDR were significant factors associated with both 2-year and overall myopia progression. Children with younger age and smaller β-PPA at baseline showed a faster myopia progression. This study suggests that the width of β-PPA, regardless of SER, might be used as a quantitative parameter to predict the potential for further myopia progression associated with scleral stretching.

Association of Scleral Deformation Around the Optic Nerve Head With Central Visual Function in Normal-Tension Glaucoma and Myopia

To investigate the structural characteristics of the posterior sclera around the optic nerve head (ONH) in patients with normal-tension glaucoma (NTG) and myopia with central visual field (VF) defect. Cross-sectional study. Ninety-seven eyes of 97 NTG patients with myopia were included in this study. Swedish interactive thresholding algorithm (SITA) 24-2 and 10-2 were both performed to compare the central VF with peripheral VF. Optic disc torsion, tilt, and peripapillary atrophy area were calculated in 2-dimensional disc photographs. The most posterior point-that is, the deepest point of the eye (DPE)-was identified in 3-dimensional en face optical coherence tomography results and related measurements were calculated using built-in software. Forty-two eyes had worse SITA 10-2 mean deviation (MD) than SITA 24-2 MD and they were assigned to the central dominant VF defect group. The central dominant VF defect group had larger disc torsion and ONH tilt angle and shallower disc-DPE depth than the peripheral dominant VF defect group. According to logistic regression analysis, large ONH tilt angle and shallow disc-DPE depth were significant factors associated with central visual function impairment. Subjects with worse central VF than peripheral showed greater peripapillary scleral deformation, such as in torsion and tilt. Their posterior scleral deformation appeared to be closer to the ONH. Scleral deformation around the ONH may be associated with papillomacular bundle and central VF defects.

Peripapillary Scleral Bowing Increases with Age and Is Inversely Associated with Peripapillary Choroidal Thickness in Healthy Eyes

To use optical coherence tomography (OCT) to 3-dimensionally characterize the optic nerve head (ONH) in peripapillary scleral bowing in non-highly myopic healthy eyes. Cross-sectional, multicenter study. A total of 362 non-highly myopic (+6 diopters [D] > spherical equivalent >-6D) eyes of 362 healthy subjects from 20-90 years old underwent OCT ONH radial B-scan imaging. Bruch's membrane (BM), BM opening (BMO), anterior scleral canal opening (ASCO), and the peripapillary scleral surface were segmented. BMO and ASCO planes were fit, and their centroids, major axes, ovality, areas and offsets were determined. Peripapillary scleral bowing was characterized by 2 parameters: peripapillary scleral slope (ppSS) of 3 anterior peripapillary scleral segments (0-300, 300-700, and 700-1,000μm from the ASCO centroid); and ASCO depth relative to a peripapillary scleral reference plane (ASCOD-ppScleral). Peripapillary choroidal thickness (ppCT) was calculated relative to the ASCO as the minimum distance between the anterior scleral surface and BM. Both ppSS and ASCOD-ppScleral ranged from slightly inward through profoundly outward in direction. Both parameters increased with age and were independently associated with decreased ppCT. In non-highly myopic healthy eyes, outward peripapillary scleral bowing achieved substantial levels, was markedly increased with age, and was independently associated with decreased peripapillary choroidal thickness. These findings provide a normative foundation for characterizing this anatomy in cases of high myopia and glaucoma and in eyes with optic disc tilt, torsion, and peripapillary atrophy.

Optic Nerve Tortuosity on Earth and in Space.

INTRODUCTION: Spaceflight Associated Neuro-ocular Syndrome (SANS) results from long-duration spaceflight and presents with a constellation of signs (e.g., optic disc edema, choroidal folds, globe flattening, refractive error shifts, etc.). Optic nerve tortuosity (ONT) has been detected in approximately 47% of astronauts after long-duration spaceflight but has not yet been fully analyzed. This review examines terrestrial ONT in order to better understand how the condition is caused and measured.METHODS: References were identified by PubMed and ScienceDirect searches covering 1955 to October 2018 using the terms "optic nerve tortuosity," "optic nerve kinking," "optic disc torsion," "optic kinking," and "ocular torsion." Additional references were identified by searching relevant articles.RESULTS: ONT measurements have evolved and become more objective. One measure consists of meeting two criteria: 1) lack of optic nerve congruity in >1 coronal section; and 2) subarachnoid space dilation. This "criteria measure" is objective, sensitive, and specific for determining the presence of tortuosity. Another measure is the tortuosity index, which offers additional benefits by measuring the degree of ONT, including the potential to track changes over time. There are numerous terrestrial ONT causes, including intracranial hypertension, hydrocephalus, Chiari malformation, neurofibromatosis, glaucoma, and progeria, among others.DISCUSSION: To accurately measure ONT, it is crucial to adhere to objective, standardized techniques. The tortuosity index offers the potential to measure intraindividual change in ONT. Among the varied conditions associated with ONT, one commonality is pressure change. The impact of intracranial pressure on the vascular system and vice versa may offer insight into what is occurring in space.Scott RA, Tarver WJ, Brunstetter TJ, Urquieta E. Optic nerve tortuosity on Earth and in space. Aerosp Med Hum Perform. 2020; 91(2):91-97.

Myopic optic disc changes and its role in glaucoma.

Optic nerve head (ONH) changes such as tilt and torsion are associated with the progression of myopia, and may in turn predispose toward glaucoma. At the same time, these ONH deformations also make the structural assessment for glaucoma difficult. Here, we review the mechanisms and changes to the myopic optic disc, and the advances in structural imaging to better evaluate the ONH in myopia. The distance, depth, and angle between the optic disc and the deepest point of the elongated eyeball may be related to the degree and direction of optic disc tilt and torsion. It is hypothesized that as the eyeball grows axially, the disc is pulled toward its most protruded point. These ONH deformations in myopia are thought to induce strain on the lamina cribrosa and the axons passing through it. Recent studies have shown unique characteristics of the lamina cribrosa in myopia that may account for susceptibility toward glaucoma. New developments in imaging the ONH in myopia, including the use of optical coherence tomography-angiography may also further our understanding of the relationship between myopia and glaucoma. Optic disc changes in myopia are secondary to the configuration of the posterior globe. These ONH deformations may predispose toward glaucoma, although the causative relationship between myopia and glaucoma remains to be further clarified.

Development of Optic Disc Torsion in Children

PurposeTo document the development of disc torsion.MethodsConsecutive disc photographs obtained at an interval of at least 1 year were reviewed retrospectively in 173 eyes of 173 Korean children. The angle of the vertical disc axis (AVDA) was measured in each fundus photograph with the fovea-disc center axis set at 0°. The associated change in the morphology of the optic disc was assessed by measuring the ratio of the horizontal to vertical disc diameters and the ratio of the maximum parapapillary atrophy width to vertical disc diameter. Eyes were divided into two groups with respect to the development of disc torsion: torsion and non-torsion group. Progressive torsion was defined as a change in AVDA between baseline and follow-up photographs beyond the coefficient of intraobserver repeatab ility. Factors associated with optic disc torsion were evaluated using logistic regression analysis.ResultsMean subject age and refractive error at the time of baseline fundus examination were 6.8 ± 1.7 (range, 2 to 11) years and 0.2 ± 2.6 (range, −6.0 to +5.5) diopters, respectively. Mean follow-up period was 44.8 ± 21.1 (range, 12 to 103) months. Forty-two eyes (24%) were classified as torsion group who showed changes in AVDA that were greater than the intraobserver measurement variability (4.5°) during the follow-up period. The development of optic disc torsion was associated with greater myopic shift, a decrease in horizontal to vertical disc diameters, and an increase in parapapillary atrophy width to vertical disc diameter.ConclusionsProgressive optic disc torsion was a common phenomenon in the children included in this study. Torsion occurred as the result of optic disc tilt in an oblique axis in most cases. The findings provide a framework for understanding torsion-related glaucomatous optic nerve damage.

Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P < .0001), and areas of rim or parapapillary elevation (P < .0001). This study reports an RNFL protrusion associated with tilted optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

Three Dimensional Evaluation of Posterior Pole and Optic Nerve Head in Tilted Disc

For over a century, tilted disc syndrome (TDS) has been defined vaguely. The lack of consensus of the terminology arises from the lack of understanding of the pathogenesis of this condition. Also, myopic discs with temporal crescents or peripapillary atrophy (PPA) are histologically indistinguishable from TDS. Therefore, we examined the morphological background of the extreme ONH appearances such as the myopic tilted disc and the TDS by analyzing the posterior segment of the eye from a three-dimensional (3D) perspective. 107 eyes of 107 subjects were classified into 3 groups with respect to the optic disc torsion degrees: (1) mild torsion (0–30 degrees; 35 eyes) and (2) moderate torsion (30–60 degrees; 35 eyes) and (3) severe torsion (60–90 degrees; 37 eyes). SSOCT images were analyzed in coronal view, which supplements anterior-posterior depth (z axis in Cartesian coordinates). The amount of optic disc torsion was significantly correlated with Disc-DPE angle and Fovea-Disc depth (r = 0.548, P < 0.001 and r = 0.544, P < 0.001). In conclusion, we describe specific types of posterior sclera configuration that corresponds to the increasing degree of optic disc torsion, even in the extreme ONH appearances such as the myopic tilted disc and the TDS. These findings suggest that the optic disc appearance is determined by the configuration of the posterior sclera.

Topographic Relationship Between Optic Disc Torsion and ß-Zone Peripapillary Atrophy in the Myopic Eyes of Young Patients With Glaucomatous-appearing Visual Field Defects.

The purpose of this study was to assess the topographic correlation between optic disc torsion (ODT) and beta-zone peripapillary atrophy (β-PPA) in young patients with myopia and glaucomatous-appearing visual field defects (VFDs). We consecutively recruited 110 eyes of 110 young patients with myopia and glaucomatous-appearing VFDs. Retinal nerve fiber layer (RNFL) and macular ganglion cell inner plexiform layer (mGCIPL) thicknesses were measured to compare between the groups with different ODT directions. For evaluating topographic correlation, the direction and degree of ODT and the direction and angles of β-PPA and point of maximum radial extent (PMRE) of β-PPA were measured on fundus photographs. Multivariate logistic regression analysis was performed to determine the clinical factors associated with inferior ODT direction. The relationships between torsional degree and clinical variables were evaluated using linear regression analyses. Among the 110 eyes, 19 had superior ODT and 91 had inferior ODT. Compared with myopic eyes with superior ODT, those with inferior ODT showed less severity of glaucoma as determined by RNFL or mGCIPL thickness and had a longer axial length, greater amount of optic disc tilt, larger β-PPA angle, and higher ratio of β-PPA area and disc area. ODT direction was significantly associated with the locations of β-PPA and PMRE. Torsional degree was significantly correlated with the β-PPA angle. ODT direction showed a significant association with the locations of β-PPA and PMRE of β-PPA. Torsional degree was correlated with the β-PPA angle in the myopic eyes of young patients with glaucomatous-appearing VFDs.

Ametropia, retinal anatomy, and OCT abnormality patterns in glaucoma. 2. Impacts of optic nerve head parameters

Clinicians use retinal nerve fiber layer thickness (RNFLT) measured by optical coherence tomography (OCT) as an adjunct to glaucoma diagnosis. Ametropia is accompanied by changes to the optic nerve head (ONH), which may affect how OCT machines mark RNFLT measurements as abnormal. These changes in abnormality patterns may bias glaucoma diagnosis. Here, we investigate the relationship between OCT abnormality patterns and the following ONH-related and ametropia-associated parameters on 421 eyes of glaucoma patients: optic disc tilt and torsion, central retinal vessel trunk location (CRVTL), and nasal and temporal retinal curvature adjacent to ONH, quantified as nasal/temporal slopes of the inner limiting membrane. We applied multivariate logistic regression with abnormality marks as regressands to 40,401 locations of the peripapillary region and generated spatial maps of locations of false positive/negative abnormality marks independent of glaucoma severity. Effects of torsion and temporal slope were negligible. The effect of tilt could be explained by covariation with ametropia. For CRVTL/nasal slope, abnormality pattern shifts at 7.2%/23.5% of the peripapillary region were detected, respectively, independent of glaucoma severity and ametropia. Therefore, CRVTL and nasal curvature should be included in OCT RNFLT norms. Our spatial location maps may aid clinicians to improve diagnostic accuracy.

Evaluation of Retinal Nerve Fiber Layer Thinning in Myopic Glaucoma: Impact of Optic Disc Morphology.

The purpose of this study was to investigate the role of optic disc torsion on the rate of progressive retinal nerve fiber layer (RNFL) thinning in patients with myopic open-angle glaucoma. We included 102 patients with myopic open-angle glaucoma accompanied by glaucomatous damage confined to a single hemiretina who were followed up over a 5-year period. We divided the subjects into three groups according to the presence or absence of optic disc torsion and the correspondence between the direction of optic disc torsion and the location of glaucomatous damage: torsion with reverse correspondence group (eyes showing inferior optic disc torsion with glaucomatous damage in the superior quadrant or eyes showing superior torsion with damage in the inferior quadrant), no torsion group, and torsion with correspondence group (eyes showing inferior optic disc torsion with glaucomatous damage in the inferior quadrant or eyes showing superior torsion with damage in the superior quadrant). Changes in the peripapillary RNFL thickness (pRNFLT), evaluated using linear mixed model analysis, were compared among the three groups to determine the relationship between optic disc torsion and pRNFLT changes. Among the total of 102 subjects, 13 eyes (12.7%) exhibited optic disc torsion with reverse correspondence, 59 (57.8%) did not exhibit optic disc torsion, and 30 (29.4%) exhibited optic disc torsion with correspondence. pRNFL thinning in the quadrant with glaucomatous damage was significantly faster in the torsion with correspondence group (-1.66 μm/y) than those in the no torsion (-1.14 μm/y; P = 0.032) and torsion with reverse correspondence (-0.50 μm/y; P < 0.001) groups. Our results suggest that the optic disc torsion-glaucomatous damage correspondence is an important prognostic factor for patients with myopic open-angle glaucoma.

Three-Dimensional Evaluation of Posterior Pole and Optic Nerve Head in Myopes with Glaucoma

The degree of myopia is represented by a global index, such as refractive error or axial length. However, the progression of myopia mainly develops in the posterior eyeball. Therefore, it is reasonable to assume that the evaluation of myopia should be confined to the posterior segment, where most of the growth and lengthening occurs. Swept source optical coherence tomography software can reconstruct the scans to the coronal view of the posterior pole, which provides additional anterior-posterior depth (z axis in the Cartesian coordinates) that is not provided with the common fundus photograph. We deduced that the parameter of deepest point of the eyeball (DPE) as a surrogate for posterior pole configuration. Between myopes with and without normal tension glaucoma (NTG) with similar axial length, myopes with NTG had deeper and more distant location of the DPE from the optic disc. The difference of the DPE position between the myopes with and without NTG may have implications for the larger optic disc tilt and torsion characteristic of myopes with NTG. Furthermore, these data suggest that myopes with NTG go through excessive posterior scleral remodeling, which may result in vulnerable optic nerve head.

The Location of the Deepest Point of the Eyeball Determines the Optic Disc Configuration

Tilted and rotated appearances are hallmarks of the myopic optic disc. As the eyeball grows axially, the posterior pole elongates not only globally but in a localized manner as well. In this process, the optic disc is pulled towards the deepest point of the elongated eyeball, which might result in a change in optic disc configuration. Thus, we hypothesized that analyzing the variation of posterior pole contour can play a major role in understanding optic disc configuration in myopic subjects. By analyzing consecutive images of swept source OCT coronal sections at the posterior pole, the deepest interface between Bruch’s membrane and the choroid could be identified as the deepest point of the eyeball (DPE). The location and the properties of the DPE differed significantly between the 125 eyes of non-glaucomatous myopic group and the 40 eyes of non-glaucomatous emmetropic group classified based on 24 mm axial length. The results suggested that the larger disc to DPE angle and the larger disc to DPE depth strongly predicts the optic disc torsion degree and the optic disc tilt. Our findings suggest that identifying the posterior pole profile plays a major role in understanding the optic disc alterations found in myopic subjects.

Retinal Nerve Fiber Layer Damage in Young Myopic Eyes With Optic Disc Torsion and Glaucomatous Hemifield Defect.

To investigate retinal nerve fiber layer (RNFL) status at the opposite hemiretinas of optic disc torsion (ODT) in young myopic subjects with glaucomatous visual field (VF) defects and correlation between its thickness and VF defects using spectral-domain optical coherence tomography (SD-OCT). We assessed the frequency and characteristics of glaucomatous RNFL defects at the opposite hemiretinas of ODT location (ODT-unaffected hemiretinas) in 59 young myopic subjects presenting with glaucomatous VF defects confined to 1 hemifield, and compared the peripapillary RNFL thickness (pRNFLT) in ODT-unaffected hemiretinas of study eyes with that of 60 myopic controls without ODT using Cirrus HD SD-OCT. Linear regression analyses were performed between the pRNFLT measurements at ODT-unaffected hemiretinas and Humphrey field analyzer VF indices. Approximately 42% of study eyes with ODT showed glaucomatous RNFL defects at ODT-unaffected hemiretinas. The mean width of RNFL defects was significantly greater in ODT-affected hemiretinas than in ODT-unaffected hemiretinas (P<0.001). The mean pRNFLT in ODT-unaffected hemiretinas of study group (99.9±12.1 μm) was significantly lower than that in the matched hemiretinas of control group (109.8±14.9 μm; P<0.001). Significant correlations were observed between pRNFLT parameters and Humphrey field analyzer indices for each hemiretina with or without ODT in the study group. Young myopic eyes with ODT and hemifield VF loss often show glaucomatous RNFL defects at both hemiretinas and significantly lower pRNFLT in the ODT-unaffected hemiretinas compared with matched hemiretinas of control eyes. Greater VF loss is associated with more advanced pRNFT loss in ODT-unaffected hemiretinas.

Comparison between Optic Disc Torsion of Fellow Eyes in Unilateral Normal-tension Glaucoma and Normal Eyes

Comparison between Optic Disc Torsion of Fellow Eyes in Unilateral Normal-tension Glaucoma and Normal Eyes

Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia. Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD. Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p < 0.001) and less SE (-7.8 ± 2.7 vs. -5.4 ± 2.5 diopters, p < 0.001). Greater tilt ratio (odds ratio (OR) = 4.9, p < 0.001), less SE (OR = 0.708, p < 0.001), and thinner average RNFL (OR = 0.910, p = 0.001) were significantly associated with GOD. Among 934 normal eyes, 366 (39.2%) displayed disc torsion, while among 26 glaucomatous eyes, eight (30.8%) displayed disc torsion. Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.

Optic Disc Characteristics and Visual Field Progression in Normal Tension Glaucoma Patients With Tilted Optic Discs.

The purpose of the study was to evaluate the optic disc characteristics associated with visual field (VF) progression in normal tension glaucoma (NTG) eyes with tilted optic discs. Sixty-six eyes of 66 NTG patients with tilted optic disc were included in this cross-sectional study, who were examined by at least 5 Humphrey 30-2 VFs. Glaucomatous VF progression was evaluated using pointwise linear regression. Optic nerve heads were scanned with enhanced-depth imaging optical coherence tomography (EDI-OCT), and evaluated for the focal lamina cribrosa (LC) defects and LC thicknesses. Optic disc torsion degrees and tilt ratios were measured from disc photographs. Logistic regression analyses were used to identify the risk factors for VF progression and focal LC defects. Multivariate analysis showed that VF progression was associated with the presence of focal LC defects and greater number of VFs. The eyes with focal LC defects were associated with greater torsion degree and tilt ratio in multivariate analysis. The VF mean deviation slopes and localized VF progression rates in eyes with focal LC defects were greater than those without defects. The greater optic disc tilt and torsion in NTG eyes with tilted optic disc were associated with focal LC defects, but not with VF progression. The focal LC defects were associated with VF progression. This study suggests that the focal LC defects in NTG patients with tilted optic disc may be an independent risk factor for glaucomatous VF progression, and the development of focal LC defects could be influenced by optic disc torsion or tilt.

Association between Corneal Deformation Amplitude and Posterior Pole Profiles in Primary Open-Angle Glaucoma

To investigate the relationships between corneal deformation amplitude and posterior pole profiles, including β-zone parapapillary atrophy (βPPA), optic disc tilt ratio, torsion degree, and disc-foveal angle, in patients with glaucoma. Cross-sectional study. A total of 107 patients with glaucoma. Each patient underwent measurement of deformation amplitude with Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany), color optic disc photography, red-free retinal nerve fiber layer photography, axial length measurement, and 24-2 standard automated perimetry. From fundus photographs, the βPPA area, optic disc tilt ratio, torsion degree, and disc-foveal angle were obtained. Pearson's correlation was used to determine the relationships between deformation amplitude and posterior pole profiles. To determine the factors associated with the posterior pole profiles, univariate and multivariate regression analyses were performed. Deformation amplitude, βPPA area, optic disc tilt ratio, torsion degree, and disc-foveal angle. The study included 50 men (46.7%) and 57 women (53.3%). The mean age was 55.38±14.14 years. The mean tilt ratio, torsion degree, and disc-foveal angle were 1.16±0.14, 10.26±7.63°, and 7.60±3.64°, respectively. The mean βPPA area was 18 211.00±28 725.53 pixels. The βPPA (r= 0.391, P < 0.001) and tilt ratio (r= 0.408, P < 0.001) had significant relationships with deformation amplitude after adjusting for intraocular pressure (IOP). Torsion degree and disc-foveal angle showed no significant relationship with deformation amplitude. The βPPA area was associated with deformation amplitude and axial length in both univariate (P=0.008 and 0.006, respectively) and multivariate (P= 0.035 and <0.001, respectively) regression analyses. The tilt ratio was associated with deformation amplitude in univariate regression analysis (P= 0.002), but not inmultivariate regression analysis. Axial length was significantly associated with the tilt ratio in both univariate (P< 0.001) and multivariate (P < 0.001) regression analyses. Deformation amplitude was associated with PPA area and tilt ratio in patients with glaucoma, although in our data set βPPA area and tilt ratio were not associated with visual field mean deviation.