Vertical Position of the Central Retinal Vessel in the Optic Disc and Its Association With the Site of Visual Field Defects in Glaucoma.

PURPOSE: The purpose of this study was to investigate the association between the vertical position of the central retinal vessel (CRV) within the optic nerve head (ONH) and the site of visual field defects (VFDs) in glaucoma. DESIGN: Cross-sectional study. METHODS: The vertical position of the CRV was identified in 134 glaucoma eyes and 61 normal eyes at the point at which CRV exited the lamina cribrosa (LC) onto the ONH surface, by using spectral-domain optical coherence tomography (exit position). The position was also identified at the entry point into the LC from the retrolaminar ONH region (entry position), which was little influenced by glaucomatous LC deformation, therefore close to the original position before the glaucoma development. Positions were compared among glaucoma eyes with different sites of VFDs, and between glaucoma and normal eyes. RESULTS: In glaucoma eyes, the entry position of the CRV was in the superior ONH region in 63.0% of eyes with superior VFDs and in the inferior ONH region in 97.8% of eyes with inferior VFDs (P < .0001). The exit position exhibited a similar percentage. The vertical CRV positions were not significantly different between glaucoma and normal eyes, both at the entry and exit positions. CONCLUSIONS: Eyes with CRVs in the superior ONH region were significantly more likely to form VFDs in the superior hemifields and vice versa. The vertical position of the CRV was little altered by the development of glaucoma. The original position of the CRV before the development of glaucoma may influence regional susceptibility to glaucomatous stress and may be useful in predicting initial sites of VFDs.

Peripapillary choroidal thickness assessed by spectral-domain optical coherence tomography in normal Japanese.

PURPOSE: To investigate peripapillary choroidal thickness (PPCT) in normal Japanese subjects by using spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI) technique and evaluate its association with ocular and systemic factors. STUDY DESIGN: Cross-sectional study. METHODS: This study included 85 eyes of 85 normal Japanese subjects. Normal subjects were defined as those without retinal and optic nerve disorders of any kind. The PPCT was measured at the location of 3.4 mm diameter peripapillary circle centered on the optic nerve head. It was measured as the distance between the retinal pigment epithelium and scleral-choroidal interface at the following six sectors; temporal, supra-temporal, supra-nasal, nasal, infero-nasal, and infero-temporal. Global PPCT was calculated based on these sectorial data. In addition, association between the PPCT and ocular and systemic factors were evaluated. RESULTS: Among the included subjects, 39 (45.9%) were men and mean age was 51.4 ± 17.6 years. The mean global PPCT was 135.8 ± 40.6 µm. The infero-nasal and infero-temporal sectors were significantly thinner than other sectors (all, P < 0.05). In multiple regression analysis, thinner global PPCT was significantly associated with older age (P < 0.0001) and female sex (P = 0.0330) after considering effects of other confounders. CONCLUSIONS: This study provided global PPCT and its profile in normal Japanese subjects by using EDI SD-OCT. These results may be used as a reference in the assessment of normal status of the PPCT. The age and sex of the subjects should be considered in interpreting the PPCT data.

Nasal displacement of retinal vessels on the optic disc in glaucoma associated with a nasally angled passage through lamina cribrosa.

To investigate nasal displacement of central retinal vessel (CRV) on the optic nerve head (ONH) in glaucoma in association with its passage through lamina cribrosa (LC). This cross-sectional study included 113 eyes with glaucoma and 60 normal eyes. Horizontal spectral-domain optical coherence tomography (SD-OCT) scans of the ONH were acquired, and point where CRV emerged on the ONH surface was defined as the position of the CRV. Next, radial scans of the ONH were acquired, and angle of the CRV passing through the LC was measured. These parameters were compared between glaucomatous and normal eyes by t-test, and their relationship with possible confounders was assessed by multiple regression analyses. In glaucoma, CRV was significantly more nasally displaced than it was in normal eyes (66.0 ± 8.6 vs. 54.3 ± 9.5, P < 0.0001), and eyes with more vessel displacement exhibited significantly worse glaucomatous visual field defects (P = 0.0004). Greater nasal displacement of the CRV was significantly associated with a more nasally angled path through the LC (rs = 0.569, P < 0.0001). By using SD-OCT, we confirmed that nasal displacement of the CRV on the ONH was associated with glaucoma and was induced by its nasally angled path through the LC.

Clinical Assessment of Scleral Canal Area in Glaucoma Using Spectral-Domain Optical Coherence Tomography.

PURPOSE: To investigate anterior scleral canal (ASC) area in the eyes with glaucoma using spectral-domain optical coherence tomography (SDOCT). DESIGN: Cross-sectional study. METHODS: This study included 206 eyes of 103 patients with glaucoma, classified as 66 eyes of 33 patients with unilateral glaucoma and 140 eyes of 70 patients with bilateral glaucoma. Radial scan enhanced depth imaging SDOCT centered on the optic disc was performed, and parameters that present ASC area such as ASC opening and the largest ASC area were obtained in each eye. The largest ASC area was the largest cross-sectional area of the ASC region identified between the ASC opening and anterior lamina cribrosa insertion. These parameters were compared between eyes with and without glaucoma in unilateral glaucoma, and eyes with worse and better visual field defect (VFD) in bilateral glaucoma. RESULTS: In the patients with unilateral glaucoma, ASC opening and largest ASC area were significantly larger in the eyes with glaucoma than in those without glaucoma (both P < .001). In bilateral glaucoma, these parameters were significantly larger in the eyes with worse VFD than in those with better VFD (P = .0080 and P = .0018, respectively). Intereye differences of the ASC parameters in the glaucoma patients were significantly greater than that in the normal subjects. CONCLUSIONS: Significantly larger ASC area was first observed in the living human eyes with glaucoma compared to the normal eyes. Further longitudinal studies are required to determine if the ASC area is useful in the prevention and treatment of glaucoma.

Differences in Retinal Nerve Fiber Layer Thickness as Assessed on the Disc Center and Bruch's Membrane Opening Center in Myopic Eyes.

PURPOSE: To investigate the difference in circumpapillary retinal nerve fiber layer thickness (cpRNFLT) assessed on the conventional, clinically identified optic disc center and Bruch's membrane opening (BMO) center in myopic eyes. DESIGN: Cross-sectional study. PARTICIPANTS: One hundred nine eyes of 109 healthy myopic subjects with axial length of 24 mm or more. METHODS: The cpRNFLT was acquired on the disc center and BMO center aligned with the fovea. The global and sectorial cpRNFLT were computed in each eye and were compared between the 2 assessments. Furthermore, factors associated with the difference in cpRNFLT between the 2 assessments were analyzed. MAIN OUTCOME MEASURES: Differences in cpRNFLT assessed on the disc center and BMO center in myopic eyes. RESULTS: Among the included participants, the mean SE was -4.94±1.69 D, and the mean axial length was 25.55±0.89 mm. The global cpRNFLT was not significantly different between the 2 assessments; however, the temporal sector was significantly thicker, and the nasal sector was significantly thinner in the assessment on the disc center than on the BMO center (P < 0.0001 for both). Forty eyes (36.7%) exhibited more than 10 µm of difference between the 2 assessments in the temporal sector. The positions of the superior and inferior peaks of the cpRNFLT profile deviated temporally significantly in the disc-center assessment (P < 0.0001 for both). Multiple regression analysis showed that the width of γ-zone parapapillary atrophy (PPA) was associated significantly with greater difference in sectorial cpRNFLT between the 2 assessments. CONCLUSIONS: There was a significant amount of difference in the sectorial cpRNFLT acquired on the disc center and that acquired on the BMO center in the myopic eyes, which was considered to be derived from unique optic disc margin anatomy in these eyes. The eyes with wider γ-zone PPA exhibited greater cpRNFLT difference. The cpRNFLT data based on the BMO center were acquired at an anatomically accurate location, which indicated that the conventional disc-center assessment induced a substantial amount of error. The present results emphasize the importance of assessing cpRNFLT on the BMO center in myopic eyes for an improved structure-function relationship.

Optic Disc Margin Anatomic Features in Myopic Eyes with Glaucoma with Spectral-Domain OCT.

PURPOSE: To investigate optic disc margin anatomic features in myopic eyes with open-angle glaucoma (OAG) using spectral-domain (SD) OCT. DESIGN: Cross-sectional study. PARTICIPANTS: Two hundred four eyes of 102 participants with OAG and 106 eyes of 53 participants without glaucoma with axial length of 24 mm or more. METHODS: Radial SD OCT B-scans centered on the optic discs were acquired in each eye, and the SD OCT data were colocalized with the optic disc stereophotographs. Optic disc margin anatomic features were evaluated as (1) SD OCT structure coinciding with the disc margin identified in the stereophotograph, (2) border tissue configuration, and (3) presence of Bruch's membrane overhang, and their frequency was computed in each clock-hour position. Further, paired eyes of myopic participants with OAG were divided into eyes with better or worse visual field defect (VFD), according to the mean deviation of the Humphrey visual field test, and associated factors were compared. MAIN OUTCOME MEASURES: Spectral-domain OCT structures coinciding with the visible optic disc margin in stereophotographs. RESULTS: In myopic eyes with OAG, mean axial length was 25.96±1.07 mm and mean deviation was -8.87±7.78 dB. In approximately 90% of the participants, anterior scleral opening (ASO) coincided with the temporal disc margin and Bruch's membrane opening (BMO) with the nasal disc margin. Border tissue configuration was externally oblique in the temporal region and internally oblique in the nasal region of the optic disc. Bruch's membrane overhang was observed in a relatively small percentage of eyes. The same pattern of disc margin anatomic features was observed in the myopic eyes without glaucoma. The myopic optic disc was shaped by the temporal shifting of the BMO from the ASO, and the extent of shifting was expressed as the width of γ zone parapapillary atrophy (PPA). The greater γ zone PPA width was associated significantly with the worse VFD between paired eyes. CONCLUSIONS: The myopic eyes with OAG exhibited characteristic optic disc margin anatomic features that was considered to be derived from myopic deformation of the eye. The greater γ zone PPA width may increase susceptibility to the glaucomatous stress.