Neuroretinal Rim Width Research Articles

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

ObjectivesThis study aimed to quantitatively evaluate optic nerve head and retinal vascular parameters in children with hyperopia in relation to age and spherical equivalent refraction (SER) using artificial intelligence (AI)-based...

Longitudinal changes in optic disc cupping from the baseline in chiasmal lesion optic neuropathy and glaucoma

We aimed to investigate the changes in cupping in chiasmal lesion optic neuropathy (chON) compared to baseline optic disc and glaucoma. We used a novel study design to enroll patients who had fundus photographs incidentally taken during routine health check-ups prior to the onset of optic neuropathy. In 31 eyes (21 patients) with chON and 33 eyes (30 patients) with glaucoma, we investigated the change in cup-to-disc (C/D) area from the baseline to overt cupping using flicker analysis. Compared to the baseline, 23 eyes (74.2%) had increased cup size and 3 (9.7%) had vascular configuration changes in the chONgroup; in contrast, all glaucoma eyes exhibited changes in cup size and vascular configuration. The increase in C/D area ratio was significantly smaller in chON (0.04 ± 0.04) compared to glaucoma (0.10 ± 0.04, P < 0.001); the minimum residual neuroretinal rim width showed a more pronounced difference (29.7 ± 8.2% vs 7.1 ± 3.9%, P < 0.001). The changes distributed predominantly towards the nasal direction in chON, contrasting the changes to the arcuate fibers in glaucoma. In conclusion, our results provide the first longitudinal evidence of true pathological cupping in chONcompared to photographically disease-free baseline. The marked difference in the residual minimum rim width reaffirms the importance of rim obliteration in the differential diagnosis between the two diseases.

Optical coherence tomography in the diagnosis of glaucomatous optical neuropathy in children with primary congenital glaucoma

Purpose: to analyze morphometric, clinical and functional manifestations of glaucomatous optical neuropathy in congenital childhood glaucoma (CG).Material and methods. We examined 103 children (163 eyes) with (CG), including 54 children (86 eyes) with primary congenital glaucoma (PCG) aged 1 month to 17 years. In addition to the regular ophthalmological examination, we performed optical coherence tomography of the optic nerve head (ONH), flash visual evoked potentials, total and rhythmic electroretinogram, oscillatory potentials (OP), echobiometry of the eye axial length.Results. The thickness of the retinal nerve fiber layer peripapillary (pRNFL) ranged from 32 to 120 μm, averaging 71.67 ± 18.2 μm. The thinning was detected in 83.0% of cases, primarily in the temporal sectors (90.6%). As the condition progressed, a tendency to progressive thinning of the RNFL was detected. The minimum rim width (BMO-MRW) ranged from 87 to 336 μm and was reduced in most children (14 out of 16, 87.5%). A strong inverse correlation of the neuroretinal rim with the depth (r = -0.69) and the width (r = -0.93) of the excavation was detected. Also, a strong direct correlation was established between the minimum neuroretinal rim width reduction and the thickness of the BMO-MRW and pRNFL (r = 0.79), as well as the upper and lower temporal sectors (r = 0.81 and r = 0.88, respectively). The thickness of the ganglion cell (GC) layer varied from 8 to 23 μm and averaged 14.64 ± 4.89 μm, with a reduction recorded in most cases (64.7%). All patients showed a decrease in oscillatory potentials (OP) by 40% or more (6.31 ± 2.33) as compared to the control group (20.24 ± 6.28). Thinning of the RNFL was registered in these eyes in 90.6% of cases averagely (p &lt; 0.05) and in the upper and the lower temporal sectors (p &lt; 0.05).Conclusion. RNFL thickness, the minimal width of the BMO-MRW and the OP are the most sensitive criteria to assess the degree of glaucomatous optic neuropathy in children with PСG. The study of the GC layer thickness can serve as an additional diagnostic criterion of assessing the state of the ONH.

Non-arteritic anterior ischemic and glaucomatous optic neuropathy: Implications for neuroretinal rim remodeling with disease severity.

Post-acute non-arteritic ischemic optic neuropathy (NAION) and glaucomatous optic neuropathy (GON) can be difficult to differentiate clinically. Our objective was to identify optical coherence tomography (OCT) parameters to help differentiate these optic neuropathies. We compared 12 eyes of 8 patients with NAION and 12 eyes of 12 patients with GON, matched for age and visual field mean deviation (MD). All patients underwent clinical assessment, automated perimetry (Humphrey Field Analyzer II; Carl Zeiss Meditec, Dublin, CA, USA), and OCT imaging (Spectralis OCT2; Heidelberg Engineering, Heidelberg, Germany) of the optic nerve head and macula. We derived the neuroretinal minimum rim width (MRW), peripapillary retinal nerve fibre layer (RNFL) thickness, central anterior lamina cribrosa depth, and macular retinal thickness. MRW was markedly thicker, both globally and in all sectors, in the NAION group compared to the GON group. There was no significant group difference in RFNL thickness, globally or in any sector, with the exception of the temporal sector that was thinner in the NAION group. The group difference in MRW increased with increasing visual field loss. Other differences observed included lamina cribrosa depth significantly greater in the GON group and significantly thinner central macular retinal layers in the NAION group. The ganglion cell layer was not significantly different between the groups. The neuroretinal rim is altered in a dissimilar manner in NAION and GON and MRW is a clinically useful index for differentiating these two neuropathies. The fact that the difference in MRW between the two groups increased with disease severity suggests distinct remodelling patterns in response to differing insults with NAION and GON.

Decoding glaucoma module premium edition.

Traditional methods for neuroretinal rim width measurement in spectral domain optical coherence tomography (SD-OCT) employs the Bruch's membrane opening (BMO) as the anatomical border of the rim, referenced to a BMO horizontal reference plane, termed as "Bruch's Membrane Opening-Horizontal Rim Width" (BMO-HRW). BMO-HRW is defined as the distance between BMO and internal limiting membrane (ILM) on the horizontal plane. In contrast, the Spectralis OCT (Heidelberg Engineering, Germany) employs a new parameter called "Bruch's Membrane Opening-Minimum Rim Width" (BMO-MRW) with Glaucoma Module Premium Edition (GMPE). GMPE provides a novel objective method of optic nerve head (ONH) analysis using BMO, but the neuroretinal rim assessment is performed from the BMO to the nearest point on the ILM, rather than on the horizontal reference plane. It is the BMO-MRW and is defined as the minimum distance between the BMO and ILM in the ONH. In this video, anatomy of the ONH and GMPE is decoded from a neophyte user's point of view, as to why BMO-MRW is more important than the traditional BMO-HRW for glaucoma evaluation. The GMPE concepts are depicted in a novel dynamic (Clinical vs OCT Vs Histology) screenplay, detailing the below focal points with 2D & 3D animations: True Margin of ONH, Bruch's Membrane (BM), Histology Vs OCT, BMO, Bruch's Membrane Opening-Minimum Rim Width, Bruch's Membrane Opening-Minimum Rim Width Versus Bruch's Membrane Opening-Horizontal Rim Width, Alpha, Beta, Gamma Zone of ONH in OCT, Anatomic Positioning System, Impact of Fovea Bruch's Membrane Opening Centre Axis. This video also highlights, how with the advent of Anatomic Positioning System, scans were able to align relative to the individual's Fovea-to-BMO-center (FoBMOC) axis at every follow-up, for accurately detecting changes, as small as 1 micron in BMO-MRW, thus creating a new world in diagnosing glaucoma and detecting glaucomatous progression with precision. https://youtu.be/6RqF5guAziw.

Agonistic autoantibodies against ß2-adrenergic receptor influence retinal microcirculation in glaucoma suspects and patients.

PurposeAgonistic β2-adrenergic receptor autoantibodies (β2-agAAb) have been observed in sera of patients with ocular hypertension and open-angle glaucoma (OAG). They target the β2-receptors on trabecular meshwork, ciliary body and pericytes (Junemann et al. 2018; Hohberger et al. 2019). In addition to their influence on the intraocular pressure, an association to retinal microcirculation is discussed. This study aimed to investigate foveal avascular zone (FAZ) characteristics by en face OCT angiography (OCT-A) in glaucoma suspects and its relationship to β2-agAAb status in patients with OAG.Material and methodsThirty-four patients (28 OAG, 6 glaucoma suspects) underwent standardized, clinical examination including sensory testing as white-on-white perimetry (Octopus G1, mean defect, MD) and structural measures as retinal nerve fibre layer (RNFL) thickness, neuroretinal rim width (BMO-MRW), retinal ganglion cell layer (RGCL) thickness, and inner nuclear layer (INL) thickness with high-resolution OCT. FAZ characteristics were measured by OCT-A scans of superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). FAZ-R was calculated (area FAZ (SVP)/area FAZ (ICP)). Using cardiomyocyte bioassays we analysed serum samples for the presence of β2-agAAb.Results(I) Total mean FAZ area [mm2]: 0.34±0.16 (SVP), 0.24±0.12 (ICP), and 0.49±0.24 (DCP); mean FAZ-R 1.58±0.94. No correlation was seen for FAZ-R with MD, RNFL, BMO-MRW, RGCL thickness and INL thickness (p>0.05). (II) ß2-agAAb have been observed in 91% patients and showed no correlation with MD, RNFL, BMO-MRW, RGCL thickness and INL thickness (p>0.05). (III) FAZ-R correlated significantly with the β2-agAAb-induced increase of the beat rate of cardiomyocyte (p = 0.028).ConclusionFAZ characteristics did not correlate with any glaucoma associated functional and morphometric follow-up parameter in the present cohort. However, level of β2-agAAb showed a significantly correlation with FAZ-ratio. We conclude that β2-agAAb might be a novel biomarker in glaucoma pathogenesis showing association to FAZ-ratio with OCT-A.

EVALUATION OF GLAUCOMA MODULE PREMIUM EDITION IN EGYPT

The mean prevalence of high myopia increases over time in Egypt Prevalence of high myopia in Egypt which was 0.2%, in 1960 increased to 7.4% in 1976 and 10.8% in 2015. Optical coherence tomography (OCT) is a noninvasive, painless and quick precise technology that can be used for interpreting tissue structure and function. Time-domain OCT was fast enough to scan a circle centered on the optic nerve head (circumpapillary) to assess the retinal nerve fiber layer (RNFL) thickness. Glaucoma Module Premium Edition (GMPE) is a new, objective method of ONH analysis using BMO. The termination of Bruch's membrane at the ONH marks the opening through which RGC axons exit the eye to form the choroidal and scleral portions of the neural canal, this anatomic opening, termed Bruch's membrane opening (BMO). The minimum distance from the BMO to the internal limiting membrane represents the most geometrically accurate measurement of neuroretinal rim width. This neuroretinal rim measurement has been termed Bruch's Membrane Opening-Minimum Rim Width (BMO-MRW).

The Impact of COVID-19 on Individuals Across the Spectrum of Visual Impairment

PurposeTO assess perceptions and implications of COVID-19 infection across the spectrum of individuals with visually impairment (VI) and those with normal sight.DesignProspective cross-sectional comparative study.MethodsSetting: institutional. Patients: 232 patients and their caregivers. Four groups were created based on better eye characteristics: blind (best-corrected distance visual acuity [BCDVA] <3/60 or visual field <10 central degrees); severe VI (BCDVA ≤3/60 to <6/60; vertical cup-to-disc ratio ≥0.85 or neuroretinal rim width ≤0.1); moderate VI (BCDVA ≤6/60 to <6/18); or no or mild VI (controls: BCDVA ≥6/18) based on International Classification of Diseases-10 criteria and Foster and Quigley's consensus definition of glaucoma. Procedure: telephone questionnaires. Main outcome measures: differences in perceptions and implications of COVID-19 infection across various levels of VI. Caregiver perceptions were a secondary outcome measure.ResultsSurveys were completed by 232 participants, with 58 participants in each VI group. Mean age was 58.9 ± 13.2 years old. Greater degrees of VI were associated with older age (P = .008) and lower education level (P = .046). Blind participants more commonly perceived vision as a risk factor for contracting COVID-19 (P = .045), were concerned about access to health care (P <.001), obtained news through word of mouth (P <.001), and less commonly wore masks (P = .003). Controls more commonly performed frequent handwashing (P = .001), were aware of telemedicine (P = .029), and had fewer concerns about social interactions (P = .020) than groups with substantial VI. All caregivers reported more frequent patient care since the COVID-19 pandemic began.ConclusionsThe pandemic might have had a disproportionate impact on the visually impaired, and evidence-based assessments of COVID-19 health outcomes in this population are warranted.

OCT-Diagnostik beim Glaukom: Tipps &amp; Tricks

High-resolution optical coherence tomography (OCT) with spectral-domain or swept-source techniques has become a mainstay in glaucoma and progression diagnosis. Imaging and morphometry of ganglion cell (GCL) and retinal nerve fiber (RNF) layer thickness and Bruch's membrane based minimum neuroretinal rim width (BMO-MRW) measurement allow the detection of pathologic changes. Graphic display of these measurements facilitate a comparison with normative data. False positive (red disease) and false negative (green disease) results represent pitfalls in OCT diagnosis. Pathologies of the posterior pole either caused by glaucoma or non-glaucoma associated changes of optic disc and retina play an important role. Epiretinal gliosis, age related macular degeneration and cystoid retinal changes cause measuring artefacts. A careful inspection of OCT B-scans is mandatory to detect these changes. Highly myopic eyes, underrepresented in normative databases cause changes resembling glaucoma and challenge the OCT glaucoma diagnosis. Neurological diseases present an important differential diagnosis when atrophy of neuroretinal tissue and ganglion cells occur. The location of the atrophy and the relationship of GCL, RNF and BMO-MRW changes may help in differential diagnosis. Sensory tests and imaging of the brain are mandatory in these cases. Drusen and disc edema cause thickening of BMO-MRW and may be followed by loss of RNF and GCL. Again a close observation of OCT B-scans and fundus may help to find the correct diagnosis. Good image quality, knowledge of OCT pathologies and technique of OCT imaging may help to avoid pitfalls in OCT glaucoma diagnosis.

Accuracy of the ISNT rule and its variants for differentiating glaucomatous from normal eyes in a population-based study

AimsTo evaluate the accuracy of the ISNT rule (I=inferior, S=superior, N=nasal, T=temporal) and its variants with neuroretinal rim width and retinal nerve fibre layer (RNFL) thickness measurements differentiating normal from...

Differential Effects of Aging in the Macular Retinal Layers, Neuroretinal Rim, and Peripapillary Retinal Nerve Fiber Layer

We determined the differential aging effects of the inner 6 layers of the macula in contrast to the minimum neuroretinal rim width (MRW) and peripapillary retinal nerve fiber layer (RNFL) thickness. Cross-sectional, multicenter study. An approximately equal number of white subjects with a normal ocular and visual field examination in each decade group from 20 to 90 years. OCT of the macula, optic nerve head, and peripapillary retina. Sectoral measurements of the inner 6 layers of the macula; age-related decline of each of these layers; strength of the associations with age of the macular parameters, MRW, and peripapillary RNFL thickness; and association between ganglion cell layer (GCL) thickness and MRW and peripapillary RNFL thickness. The study sample comprised 1 eye of 246 subjects with a median (range) age of 52.9 (19.8-87.3) years. Of the 6 layers, there was a statistically significant decline with age of only the GCL, inner plexiform layer, and inner nuclear layer thickness with rates of-0.11 μm/year,-0.07 μm/year, and-0.03 μm/year, respectively. These rates corresponded to 2.82%, 2.10%, and 0.78% loss per decade, respectively, and were generally uniform across sectors. The rate of loss of MRW and peripapillary RNFL thickness was-1.22 μm/year and-0.20 μm/year, corresponding to 3.75% and 2.03% loss per decade. However, the association of GCL thickness change with age (R2 = 0.28) was approximately twice that of MRW and RNFL thickness (R2 = 0.14 for each). In concordance with histopathologic studies showing age-related loss of retinal ganglion cell axons, we showed a significant decline in GCL thickness, as well as MRW and peripapillary RNFL thickness. The stronger relationship between aging and GCL thickness compared with the rim or peripapillary RNFL may indicate that GCL thickness could be better suited to measure progression of structural glaucomatous loss.

Predictive Diagnosis of Glaucoma Based on Analysis of Focal Notching along the Neuro-Retinal Rim Using Machine Learning

Automatic evaluation of the retinal fundus image is regarded as one of the most important future tools for early detection and treatment of progressive eye diseases like glaucoma. Glaucoma leads to progressive degeneration of vision which is characterized by shape deformation of the optic cup associated with focal notching, wherein the degeneration of the blood vessels results in the formation of a notch along the neuroretinal rim. In this study, we have developed a methodology for automated prediction of glaucoma based on feature analysis of the focal notching along the neuroretinal rim and cup to disc ratio values. This procedure has three phases: the first phase segments the optic disc and cup by suppressing the blood vessels with dynamic thresholding; the second phase computes the neuroretinal rim width to detect the presence and direction of notching by the conventional ISNT rule apart from calculating the cup-to-disc ratio from the color fundus image (CFI); the third phase uses linear support vector based machine learning algorithm by integrating extracted parameters as features for classification of CFIs into glaucomatous or normal. The algorithm outputs have been evaluated on a freely available database of 101 images, each marked with decision of five glaucoma expert ophthalmologists, thereby returning an accuracy rate of 87.128%.

Diagnostic criteria for detection of retinal nerve fibre layer thickness and neuroretinal rim width abnormalities in glaucoma

Background/aimsAlthough measurements of the Bruch’s membrane opening minimum rim width (BMO-MRW) and retinal nerve fibre layer thickness (RNFLT) with optical coherence tomography (OCT) have been widely adopted in the diagnostic...

Comparison of Spectralis and Cirrus spectral domain optical coherence tomography for the objective morphometric assessment of the neuroretinal rim width

PurposeThe assessment of cup-disc ratio as a surrogate parameter for the neuroretinal rim width (NRW) of the optic nerve is well established, but prone to human error and imprecision. Objective assessment of the NRW is provided by spectral domain optical coherence tomography (SD-OCT). This study is the first to systematically compare NRW measurements acquired with the Carl Zeiss Meditech Cirrus HD-OCT 5000 and the Heidelberg Engineering Spectralis SD-OCT.MethodsIn this cross-sectional study, 20 eyes of each 20 glaucoma patients and 20 age-matched healthy controls underwent ophthalmic examination, SD-OCT imaging, and computer perimetry. Regression analyses were performed for the NRW comparability and the effect of the rotational alignment disconcordance (RAD), receiver-operating characteristics (ROC) for NRW-based healthy glaucoma discrimination capability, and Pearson’s correlation for covariate association.ResultsMean NRW differences were 8 ± 48 μm (p = 0.4528), 91 ± 80 μm (p < 0.01), and 49 ± 77 μm (p < 0.001) in the glaucoma, healthy, and whole group. On average, the Cirrus showed higher NRW values (+ 50 μm) than the Spectralis, this difference increased with values starting with 159 μm. Discrimination ROC were 1.0 (Spectralis) and 0.9675 (Cirrus). RAD showed very little effect on NRW (R2 = 0.9661, p < 0.001). NRW-covariate correlation was highly significant (p < 0.001) with both devices for clinical cup/disc ratio, calculated rim width, visual field mean, and pattern deviations.ConclusionsOur results suggest to only cautiously compare Spectralis and Cirrus NRW measurements only in patients with morphologically manifest glaucoma. For morphological progression analysis, we recommend the continuous usage of the same device.

The Relationship Between Optic Disc Parameters and Female Reproductive Factors in Young Women.

It has been suggested that female sex steroids have neuroprotective properties that may reduce risk of glaucoma in premenopausal women. In this study, we explored the associations of optic disc measures with female reproductive factors in a population of young women. Cohort study. Young women (n = 494; age range, 18-22 years) were recruited as part of the Western Australian Pregnancy Cohort (Raine) Study. Information on age at menarche, parity, and use of hormonal contraceptives were obtained from questionnaires. Participants underwent an eye examination, including spectral-domain optical coherence tomography imaging, to obtain optic disc parameters. Women who had given birth at least once (parous women; n = 10) had larger vertical neuroretinal rim widths (P < 0.001) than nulliparous women (n = 484) after correcting for use of hormonal contraceptives, intraocular pressure, refractive error, and family history of glaucoma. Furthermore, vertical and horizontal cup-to-disc ratios, which are inherently related to neuroretinal rim width, were found to be smaller among parous women compared with nulliparous women (both P < 0.001). Age at menarche and use of hormonal contraceptives were not significantly associated with any optic disc parameters. We found limited evidence that female reproductive factors were related with optic disc parameters during young adulthood. The association between parity and optic disc parameter, though significant, should be further investigated given the small number of parous women in the current sample. Future follow-ups of this cohort will allow us to explore for any associations of these factors with optic disc parameters and glaucoma risk at an older age.

New approaches to the treatment of patients with dry age-related macular degeneration and concomitant mild stabilized open-angle glaucoma

Relevance. Dystrophic processes in the retina and different types of glaucoma occupy a significant place among ocular disabling conditions. In the present article, the institutions experience concerning a new approach to treatment of patients with dry age-related macular degeneration and concomitant mild stabilized open-angle glaucoma.&#x0D; Aim. To clinically estimate the influence of the biologically active dietary supplement Proluksa on main visual functions and on the quality of life in patients with dry age-related macular degeneration and concomitant mild stabilized open-angle glaucoma.&#x0D; Materials and methods. Into the study, 60 patients were included; they were divided into two groups. Patients of the first group received the biologically active dietary supplement Proluksa, 2 capsules once a day during three months, and instilled IOP-lowering drops; patients of the second group did not take the biologically active dietary supplement Proluksa, they instilled IOP-lowering drops only. Both groups were followed during six months. Three times a standard ophthalmologic examination and instrumental investigations (macular electroretinography, vacuum-compression test with control of visual evoked cortical potentials using a suction cup, HRT III of the optic disc, OCT of the macular area) were performed in both groups.&#x0D; Results. There was a statistically significant positive visual acuity dynamics at stable optimal correction for distance in the group 1; the percentage of relative scotomata decreased in the group 1; vacuum-compression test gave negative results at Visits 1, 2, and 3; the p-100 wave amplitude increased in the group 1 on the background the biologically active dietary supplement Proluksa intake; the a-wave amplitude of the macular ERG increased; according to OCT results, there were no reliable changes in the central retinal area; the optic disc neuroretinal rim width at HRT III remained stable during the whole follow-up period.&#x0D; Conclusions. According to performed investigations, there were: statistically reliable visual acuity increase at stable optimal correction, statistically significant positive dynamics in retinal photosensitivity, and increase in functional activity of external and internal retinal layers in the macular area. To the third month of preparation intake, patients from the group 1 taking the biologically active dietary supplement Proluksa noted the enhancement of image resolution, decrease in visual defocusing, better color perception.

Association of Bruch's membrane opening and optic disc morphology to axial length and visual field defects in eyes with primary open-angle glaucoma.

To examine the morphology of Bruch's membrane opening (BMO), optic disc, and peripapillary atrophy (PPA) by scanning laser ophthalmoscopy (SLO) and spectral-domain optical coherence tomography (SD-OCT), and to determine their association with the axial length and visual field defects. This was a cross-sectional study of 94 eyes of 56 subjects; 77 eyes were diagnosed with primary open-angle glaucoma and 17 eyes as normal. The margins of the optic disc were determined in the SLO images, and that of the BMO in the SD-OCT images. The ovality and area of the BMO and the optic disc were measured. The beta and gamma-PPA areas were also measured. The association of each parameter with the axial length and the mean deviation (MD) of the visual field tests was determined by generalized estimating equations (GEEs). The optic disc ovality was associated with the axial length and the MD (β = -0.47, P = 7.6 × 10-4 and β = 0.12, P = 0.040). The BMO ovality was not significantly associated with the axial length and the MD. The BMO area was associated with the axial length (β = 0.30, P = 0.029). A larger BMO area was associated with a thinner BMO-based neuroretinal rim width (BMO-MRW) after adjustments for the MD (β = -0.30, P = 2.1 × 10-4). The beta- and gamma-PPA areas were associated with the axial length (β = 0.50, P = 7.4 × 10-5 and β = 0.62, P = 4.2 × 10-6). The optic disc ovality was associated with both the axial length and MD, whereas BMO ovality was not. Attention should be paid to the influence of the axial length-related enlargement of the BMO.

Optical coherence tomography angiography in glaucoma: a mini-review.

The advent of optical coherence tomography angiography (OCT-A) provides a new opportunity to visualize the retinal vasculature in a non-invasive and dye-free manner which may help identify vascular abnormalities in glaucoma. While a reduction in retinal and optic nerve head vessel densities and blood flow indexes measured by OCT-A has been demonstrated in patients with glaucoma in many studies, it is unclear whether OCT-A provides additional information for the detection and monitoring of glaucoma compared with OCT measurements such as retinal nerve fiber layer thickness, neuroretinal rim width, and ganglion cell inner plexiform layer thickness. Longitudinal studies are needed to elucidate whether vascular abnormalities detected by OCT-A are a cause or a consequence of optic nerve damage in glaucoma.

Principles of glaucoma diagnostics with optical coherence tomography

In recent years many applications of optical coherence tomography (OCT) have led to a better understanding of glaucoma morphology. The clinical routine in the treatment of glaucoma is strongly influenced by the modern diagnostic aspects. A selective search of the literature was carried out and the important aspects are presented taking own experiences into account. The measurement principles, diagnostic ability and pitfalls of the three OCT measurement procedures are highlighted. Retinal nerve fiber layer, macula and ganglion cell layer thickness as well as the minimum neuroretinal rim width have facilitated in particular the objective early diagnosis and follow-up measurements. For glaucoma, OCT measurements cannot replace the medical expert diagnosis but they represent a valuable decision-making aid for diagnostics and follow-up examinations.

Determinants of Optical Coherence Tomography–Derived Minimum Neuroretinal Rim Width in a Normal Chinese Population

To characterize an optical coherence tomography (OCT)-derived parameter, Bruch's membrane opening-minimum rim width (BMO-MRW), and its association with demographic and clinical parameters in normal Chinese subjects. Right eyes of 466 consecutive healthy subjects from a population-based study of Singaporean Chinese underwent Cirrus OCT imaging. The retinal internal limiting membrane (ILM) and BMO were automatically delineated using the built-in Cirrus algorithm. The standard 36 interpolated radial B-scans (72 BMO points, 5° increments) of each optic nerve head were manually extracted from the central circle (3.46-mm diameter). We used Matlab to measure the shortest distance from the BMO points to the ILM. Associations of BMO-MRW with demographic and clinical parameters were evaluated using marginal general estimating equations analysis. There was a slight preponderance of male subjects (50.9%), with a mean age of 54.8 ± 7.63 years. Mean BMO-MRW was 304.67 ± 58.96 μm (range, 173.32-529.23 μm), which was highly associated with OCT-derived disc area (DA) (β = -91.78, P < 0.001) and rim area (RA) (β = 194.31, P < 0.001), followed by spherical refractive error (SRE) (β = -2.23, P = 0.02) and retinal nerve fiber layer (RNFL) thickness (β = 0.5, P = 0.04), after adjusting for the associated factors such as age, sex, intraocular pressure (IOP), and vertical cup-disc ratio (VCDR). Disc area and RA had the strongest association with BMO-MRW, followed by SRE and RNFL thickness. The availability of this normative database will facilitate optic nerve head assessment using the BMO-MRW parameter in Chinese subjects.