Classifying patterns of localized glaucomatous visual field defects on automated perimetry

Segmentation-Free OCT-Volume-Based Deep Learning Model Improves Pointwise Visual Field Sensitivity Estimation

Purpose

The structural changes measured by optical coherence tomography (OCT) are related to functional changes in visual fields (VFs). This study aims to accurately assess the structure-function relationship and overcome the challenges brought by the minimal measurable level (floor effect) of segmentation-dependent OCT measurements commonly used in prior studies.

Methods

We developed a deep learning model to estimate the functional performance directly from three-dimensional (3D) OCT volumes and compared it to the model trained with segmentation-dependent two-dimensional (2D) OCT thickness maps. Moreover, we proposed a gradient loss to utilize the spatial information of VFs.

Results

Our 3D model was significantly better than the 2D model both globally and pointwise regarding both mean absolute error (MAE = 3.11 + 3.54 vs. 3.47 ± 3.75 dB, P < 0.001) and Pearson's correlation coefficient (0.80 vs. 0.75, P < 0.001). On a subset of test data with floor effects, the 3D model showed less influence from floor effects than the 2D model (MAE = 5.24 ± 3.99 vs. 6.34 ± 4.58 dB, P < 0.001, and correlation 0.83 vs. 0.74, P < 0.001). The gradient loss improved the estimation error for low-sensitivity values. Furthermore, our 3D model outperformed all prior studies.

Conclusions

By providing a better quantitative model to encapsulate the structure-function relationship more accurately, our method may help deriving VF test surrogates.

Translational Relevance

DL-based VF surrogates not only benefit patients by reducing the testing time of VFs but also allow clinicians to make clinical judgments without the inherent limitations of VFs.

Visual Characteristics of Adults with Long-Standing History of Dietary Exposure to Mercury in Grassy Narrows First Nation, Canada

Since the 1960s, Grassy Narrows First Nation (Ontario, Canada) has been exposed to methyl mercury (Hg) through fish consumption, resulting from industrial pollution of their territorial waters. This cross-sectional study describes the visual characteristics of adults with documented Hg exposure between 1970 and 1997. Oculo-visual examinations of 80 community members included visual acuity, automated visual fields, optical coherence tomography [OCT], color vision and contrast sensitivity. Median age was 57 years (IQR 51-63) and 55% of participants were women. Median visual acuity was 0.1 logMAR (Snellen 6/6.4; IQR 0-0.2). A total of 26% of participants presented a Visual Field Index inferior to 62%, and qualitative losses assessment showed concentric constriction (18%), end-stage concentric loss (18%), and complex defects (24%). On OCT, retinal nerve fiber layer scans showed 74% of participants within normal/green range. For color testing with the Hardy, Rand, and Rittler test, 40% presented at least one type of color defect, and with the Lanthony D-15 test, median color confusion index was 1.59 (IQR 1.33-1.96). Contrast sensitivity showed moderate loss for 83% of participants. These findings demonstrate important loss of visual field, color vision, and contrast sensitivity in older adults in a context of long-term exposure to Hg in Grassy Narrows First Nation.

Threat to fixation and vision-related quality of life in early open-angle glaucoma - results from the Glaucoma Intensive Treatment Study

PURPOSE

To determine the effect of glaucomatous visual field (VF) damage close to the point of fixation, called threat-to-fixation (TTF), on vision-related quality of life (VRQoL) in open-angle glaucoma.

METHODS

A total of 239 patients from the Glaucoma Intensive Treatment Study (GITS) were included in this analysis. The second VF of patients with newly diagnosed primarily early glaucoma was evaluated for the presence or absence of TTF. TTF was defined as VF loss including one or more of the four innermost test points depressed at p < 1% in the total deviation probability map of Humphrey 24-2 SITA Standard visual fields. VRQoL was evaluated using Rasch-analysed National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) scores. The correlation between VRQoL and TTF was evaluated using uni- and multivariable regression analyses.

RESULTS

TTF was present in at least one eye in 115 patients (48%); located in the superior hemifield alone in 47% (54 of 115), in the inferior hemifield alone in 23% (27 of 115), and in 30% (34 of 115) in both hemifields. The median Rasch-calibrated NEI VFQ-25 scores were identical when comparing patients with TTF (VRQoL score 66, 95% CI: 23-100) and those with no-TTF (VRQoL score 66, 95% CI: 21-100) (p = 0.925). Neither the presence of TTF (R²  = -0.004, p = 0.968) nor the location of TTF (R²  = 0.023, p = 0.103) was significantly correlated to Rasch-calibrated NEI VFQ-25 scores.

CONCLUSION

The presence of TTF did not influence VRQoL, as measured by the NEI-VFQ-25, in this relatively large group of patients with mainly early glaucoma.

Contrast-to-Noise Ratios to Evaluate the Detection of Glaucomatous Progression in the Superior and Inferior Hemiretina

Purpose

To determine the sensitivity of optical coherence tomography (OCT) and standard automated perimetry (SAP) for detecting glaucomatous progression in the superior and inferior hemiretina.

Methods

We calculated contrast-to-noise ratios (CNRs) for OCT retinal nerve fiber layer (RNFL) thickness of hemiretinas and for SAP mean total deviation (MTD) of the corresponding hemifields from longitudinal data (205 eyes, 125 participants). The glaucoma stage for each hemiretina was based on the corresponding hemifield's MTD. Contrast was defined as the difference of the parameter between two consecutive glaucoma stages, whereas noise was the measurement variability of the parameter in those stages. The higher the CNR of a parameter, the more sensitive it is to detecting progression in the transition between successive stages.

Results

There were no statistically significant differences for the RNFL CNR and MTD CNR between superior and inferior hemiretinas. As the glaucoma stage of the opposite hemiretina worsened, the MTD CNR in the transition from moderate to advanced glaucoma significantly increased. The RNFL CNR in the transition from mild to moderate glaucoma significantly decreased in case of advanced glaucoma in the opposite hemiretina.

Conclusions

Similar to full retinas, detecting conversion to glaucoma in hemiretinas is more sensitive with OCT than SAP, whereas with more advanced disease, SAP is more sensitive for detecting progression. More importantly, the sensitivity for detecting progression in one hemiretina with either technique depends on the glaucoma severity in the opposite hemiretina.

Translational Relevance

Monitoring glaucomatous progression with either OCT or SAP partly depends on the glaucoma severity in the opposite hemiretina.

Functional evaluation of the macular area in early glaucoma using microperimetry

Purpose:

To evaluate the central visual field by microperimetry (MP), in early glaucoma.

Methods:

Consecutive perimetrically experienced patients with a single nasal step or arcuate scotoma and 14 control eyes underwent MP. Retinal sensitivity on MP was mapped for frequency and depth of loss in the central 10° around fixation.

Results:

Twenty-one eyes had a single nasal step and 19 eyes with single arcuate scotoma on standard automated perimetry (SAP), with central 10° being normal on 30–2 and 10–2 perimetry. The average mean sensitivity on MP, in glaucomatous and control eyes was 11.8 ± 3.9 dB and 16.6 ± 1.2 dB, respectively, P = 0.0004. The average mean defect on MP-1, in glaucomatous and control eyes was - 6.5 ± 2.0 dB and - 3.0 ± 1.2 Db, respectively, P = 0.05. The corresponding retinal hemisphere showed significant defects in MP. In eyes with single nasal steps, an absolute scotoma was seen in 14–28% of eyes 8–10° off fixation, moderate to mild defects were seen in 10–52% eyes, and 10% eyes showed involvement up to 4° from the fixation. Eyes with arcuate scotoma had an absolute scotoma on MP in 95% of eyes, 6–10° from fixation, with extension up to 2° from fixation in 21%. In glaucomatous eyes, the normal hemisphere on SAP showed a mild defect on MP in 43%. Control eyes did not show any defect in SAP or MP.

Conclusion:

A significant loss of central retinal sensitivity is recorded on MP in early glaucomatous neuropathy as compared to SAP. Paramacular absolute defects were seen at 6–10° from fixation.

Studying the role of 10-2 visual field test in different stages of glaucoma

Objective:

To assess the role of 10-2 visual field (VF) test in different stages of glaucoma.

Methods:

In our prospective comparative study, 24-2 and 10-2 VF tests were done for 115 eyes with different stages of glaucomatous damage or glaucoma suspects. Optical coherence tomography (OCT) was performed in 79 eyes. We compared field changes of the central 10° on 10-2 and 24-2 tests and studied the correlation between the mean deviation (MD) measured by the two tests.

Results:

In seven glaucoma suspects, glaucoma diagnosis was missed by 24-2 test but was detected by 10-2 test and confirmed by OCT. In the eyes with early damage, there was no correlation between 10-2 and 24-2 tests regarding the MD of the central 10º. In moderate and severe stages, there was a significant correlation between the results of 24-2 and 10-2 tests.

Conclusion:

We concluded that 10-2 test could help confirm glaucoma diagnosis in glaucoma suspects missed by 24-2 test before resorting to the more expensive OCT. In early glaucoma, we noted that 10-2, as confirmed by OCT, was a beneficial addition to 24-2 test for precise measurement of the MD and detection of defects of the central 10º missed by 24-2 test, where more intense treatment should be considered to preserve the threatened central visual function. In moderate and severe cases, the role of 10-2 test was not as pivotal as in early cases, but still it was useful for assessment of residual central visual function in severe cases with absolute central 10º defects on 24-2 test for proper management.

Pattern Electroretinogram Detects Localized Glaucoma Defects

Purpose

We evaluated the clinical ability of pattern electroretinogram (PERG) to detect functional losses in the affected hemifield of open-angle glaucoma patients with localized perimetric defects.

Methods

Hemifield (horizontally-defined) steady-state PERGs (h-PERGs) were recorded in response to 1.7 c/deg alternating gratings from 32 eyes of 29 glaucomatous patients with a perimetric, focal one-hemifield defect, 10 eyes of 10 glaucomatous patients with a diffuse perimetric defect, and 18 eyes of 18 age-matched normal subjects. Standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) for retinal nerve fiber layer (RNFL) thickness also were performed. h-PERG amplitudes and ratios, calculated corresponding hemifield perimetric deviations, as well as hemiretina RNFL thicknesses were analyzed.

Results

h-PERG amplitudes, perimetric deviations, and RNFL thicknesses showed losses (P < 0.001) when comparing affected with unaffected hemifields of localized glaucomatous eyes. No differences were found in h-PERG amplitudes between hemifields of normal or diffuse glaucomatous eyes. h-PERG amplitude ratios (affected/unaffected hemifield) in localized glaucoma were lower (P < 0.001) than the ratios from normal or diffuse glaucomatous eyes. The areas under the receiver operating characteristic curves for h-PERG amplitude ratios, comparing localized-defect glaucomatous eyes with normal or diffuse glaucomatous eyes, were 0.93 and 0.91, respectively.

Conclusions

h-PERG assessment showed good diagnostic accuracy to confirm localized glaucomatous defects detected perimetrically. This test may be particularly useful in cognitively impaired patients or young/nonverbal patients unable to provide reliable visual fields.

Translational Relevance

h-PERG provides a sensitive objective measure to confirm focal losses detected with SAP and/or RNFL thickness analysis.

Detectability of Visual Field Defects in Glaucoma With High-resolution Perimetry

PURPOSE

To extrapolate the optimal test point resolution for assessment of glaucomatous visual field (VF) defects including subtle functional defects, we performed high-resolution perimetry with the 0.5 degrees test point resolution.

SUBJECTS AND METHODS

Subjects were 11 eyes of 11 normal volunteers and 16 eyes of 16 glaucomatous patients. Octopus 900 custom test was used to measure 61 points with the test point resolution of 0.5 degrees on the temporal meridian of 45 degrees within the eccentricity of 30 degrees. In the glaucoma cases, VF profiles were extracted in 17 patterns of the test point resolutions that ranged from 0.5 to 8.5 degrees and the mean defect (MD), square root of loss variance (sLV), and maximum sensitivity loss (Max loss) were calculated. The influence of the test point resolution on MD, sLV, and Max loss was examined. In addition, the test range from the fixation point to the eccentricity of 30 degrees was divided into 3 zones. Similarly, each zone was investigated if the test point resolution exerted influence on the MD, sLV, and Max loss.

RESULTS

Our glaucoma cases did not show any significant differences in MD and sLV regardless of the resolution. Max loss showed significant difference at resolution ≥1.0 degree. MD and sLV did not show significant differences by the change of resolution in each zone. Max loss showed significant differences at resolution ≥1.5 degrees within the central 10 degrees.

CONCLUSIONS

To detect subtle VF defects within the eccentricity of 10 degrees, high-resolution perimetry with the test point resolution of <1.5 degrees is necessary.

Diagnostic ability of Humphrey perimetry, Octopus perimetry, and optical coherence tomography for glaucomatous optic neuropathy

PurposeTo evaluate and compare the diagnostic accuracy of the Humphrey Field Analyzer (HFA), Octopus perimetry, and Cirrus OCT for glaucomatous optic neuropathy.MethodsEighty-eight healthy individuals and 150 open-angle glaucoma patients were consecutive and prospectively selected. Eligibility criteria for the glaucoma group were intraocular pressure ≥21 mm Hg and glaucomatous optic nerve head morphology. All subjects underwent a reliable standard automated perimetry with the HFA and Octopus perimeter, and were imaged with the Cirrus OCT. Receiver-operating characteristic (ROC) curves were plotted for the threshold values and main indices of the HFA and Octopus, the peripapillary retinal nerve fiber layer thicknesses, and the optic nerve head parameters. Sensitivities at 85 and 95% fixed-specificities were also calculated. The best areas under the ROC curves (AUCs) were compared using the DeLong method.ResultsIn the glaucoma group, mean deviation (MD) was -5.42±4.6 dB for HFA and 3.90±3.6 dB for Octopus. The MD of the HFA (0.966; P<0.001), mean sensitivity of the Octopus (0.941; P<0.001), and average cup-to-disc (C/D) ratio measured by the Cirrus OCT (0.958; P<0.001) had the largest AUCs for each test studied. There were no significant differences among them. Sensitivities at 95% fixed-specificity were 82% for pattern standard deviation of the HFA, 81.3% for average C/D ratio of OCT, and 80% for the MD of the Octopus.ConclusionsHFA, Octopus, and Cirrus OCT demonstrated similar diagnostic accuracies for glaucomatous optic neuropathy. Visual field and OCT provide supplementary information and thus these tests are not interchangeable.

The Effects of Nocturnal Dip and Blood Pressure Variability on Paracentral Scotoma in Early Open-Angle Glaucoma

PURPOSE

To evaluate the effect of nocturnal dip and blood pressure (BP) variability on paracentral scotoma in early open-angle glaucoma.

METHODS

The present study included 72 early normal-tension glaucoma (NTG) patients and 34 early primary open-angle glaucoma (POAG) patients. Nocturnal dip and weighted standard deviation (wSD) were determined by 24-hour ambulatory BP monitoring (24-hr ABPM). The mean deviation (MD) and pattern deviation (PD) were measured with visual field. Correlations between nocturnal dip and/or BP variability and paracentral scotoma were assessed using Student's t-test, Pearson's correlation test, and linear logistic regression analysis.

RESULTS

The systolic and diastolic nocturnal dip and paracentral scotoma occurrence demonstrated a statistically significant correlation in the early NTG group (systolic nocturnal dip: p=0.047, diastolic nocturnal dip: p=0.011). In the early NTG group, the subgroup with paracentral scotoma had a greater nocturnal dip than those patients without paracentral scotoma (systolic nocturnal dip: p=0.000; diastolic nocturnal dip: p=0.000). In the early NTG group, the subgroup with paracentral scotoma had higher wSD of SBP than the patients without paracentral scotoma (p=0.003). In the logistic regression analysis of the factors that can affect paracentral scotoma SBP dip and SBP, wSD appeared to significantly affect the occurrence of paracentral scotoma in the early NTG group.

CONCLUSIONS

Early NTG patients with paracentral scotoma have nocturnal dip and large BP variability. Therefore, in early glaucoma patients, particularly in early NTG with paracentral scotoma, nocturnal dip and BP variability should be assessed with 24-hr ABPM.

Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Generated by Spectral-Domain OCT in Glaucoma Patients and Normal Subjects

PURPOSE

To elucidate patterns of macular ganglion cell-inner plexiform layer (GCIPL) defects by Cirrus optical coherence tomography (OCT) and examine the spatial relationship between GCIPL defect and visual field (VF) defect patterns.

METHODS

A total of 116 eyes of 116 normal subjects and 111 eyes of 111 glaucoma patients were included. The 227 study subjects underwent Cirrus OCT imaging in macular cube mode and reliable standard VF testing. Two ophthalmologists blindly classified GCIPL defect patterns and VF defects. The frequency distribution of GCIPL defect patterns and spatial relationships between GCIPL defects and VF defects were investigated.

RESULTS

GCIPL defect patterns were classified as minimal, inner, outer, diffuse mild, diffuse severe, inferior confined, inferior dominant, superior confined, and superior dominant defects in normal controls (71.6%, 7.8%, 4.3%, 1.7%, 0%, 10.3%, 1.7%, 1.7%, and 0.9%, respectively) and in glaucoma patients (11.7%, 3.6%, 4.5%, 7.2%, 21.6%, 22.5%, 18.0%, 4.5%, and 6.3%, respectively). In mild and moderate glaucoma patients, the inferior confined type was most frequent (21.9% and 50.0%, respectively). However, the diffuse severe type was most frequent (59.1%) in advanced glaucoma patients. The locations of the VF defects corresponded to the locations of the GCIPL defects in glaucoma patients (P=0.012).

CONCLUSIONS

Glaucomatous damage of the macula was common and more frequent in the inferior retina. GCIPL defect patterns as determined by SD-OCT imaging corresponded well with central VF defects. It seems macular GCIPL analysis may be useful for evaluating glaucomatous optic neuropathy.

Validity of the temporal-to-nasal macular ganglion cell-inner plexiform layer thickness ratio as a diagnostic parameter in early glaucoma

PURPOSE

To evaluate the diagnostic validity of temporal-to-nasal macular ganglion cell-inner plexiform layer thickness (TNM) ratio using Cirrus high definition-optical coherence tomography (HD-OCT) in patients with early glaucomatous damage.

METHODS

Enrolled participants included 130 normal controls, 50 patients with preperimetric glaucoma and 106 patients with early glaucoma. The patients with early glaucoma were classified into two subgroups according to the pattern of the visual field (VF) defects: the paracentral scotoma (PCS, n = 54) and the peripheral scotoma (PPS, n = 52). The thickness of the macular ganglion cell-inner plexiform layer (mGCIPL) and circumpapillary retinal nerve fibre layer (cpRNFL) was measured by Cirrus HD-OCT, and the average, superior and inferior TNM ratio was calculated. The average TNM ratio is a sum of superotemporal and inferotemporal mGCIPL thicknesses divided by the sum of superonasal and inferonasal mGCIPL thicknesses. Area under the receiver operating characteristic curve (AROC) of each parameter was compared between the groups.

RESULTS

The parameter with the best AROC was the average TNM ratio and inferotemporal mGCIPL thickness in the PCS group and average cpRNFL thickness in the PPS group. The AROCs of the average, superior and inferior TNM ratio (p < 0.001, p = 0.007 and p < 0.001, respectively), minimum, average, inferotemporal and inferior mGCIPL thickness (p = 0.004, p = 0.003, p = 0.002 and p = 0.001, respectively) of the PCS were significantly higher than those of the PPS. However, the AROCs of the all cpRNFL thickness parameters did not show statistically significant differences between two subgroups.

CONCLUSION

Asymmetry of temporal-to-nasal mGCIPL thickness could be an important parameter in the diagnosis of early glaucoma with paracentral VF defects.

Temporal retinal thickness in eyes with glaucomatous visual field defects using optical coherence tomography

PURPOSE

To evaluate the temporal macular retinal thickness in normal, early, and advanced glaucomatous eyes using optical coherence tomography 3 (OCT-3) and correlate the superior-to-inferior retinal thickness (S/I RT) ratio with corresponding field defects in early and advanced glaucoma patients.

PATIENTS AND METHODS

Forty normal eyes, 40 eyes with early glaucomatous visual field defects, and 33 eyes with advanced visual field defects were included. All participants underwent complete ocular and visual field examinations and OCT-3 imaging on the same day. A 3×3 mm area temporal to the foveal reflex was scanned with the OCT-3 using 6 horizontal, equally spaced raster lines. Retinal thickness was evaluated at points 500 μm apart for each line and S/I RT ratio computed between similar points above and below the fovea for each patient. One-way ANOVA was used to compare S/I RT ratio between the normal, early, and advanced glaucoma eyes.

RESULTS

Average retinal thickness increased progressively, as points temporal to the fovea were scanned. There was a statistically significant difference between the average superior and inferior retinal thickness at points 1500, 2000, and 2500 μm temporal to the fovea in both early and advanced glaucoma eyes (P<0.05) with corresponding significant differences in the S/I RT ratios, when compared with the normal participants (P<0.017).

CONCLUSIONS

OCT-3-generated S/I RT ratios were successfully able to reproduce the structural damage in eyes with early and advanced glaucoma field defects and can complement optic disc scanning protocols in diagnosing glaucoma at an early stage.

Validity and reliability of eye healthcare professionals in the assessment of glaucoma - a systematic review

OBJECTIVE(S)

To explore the validity and reliability of eye healthcare professionals with different levels of training in diagnosing and/or identifying glaucomatous progression.

CLINICAL RELEVANCE

Substantial pressure is being placed on our current eye healthcare workforce by chronic diseases such as glaucoma. Shared care schemes and role expansion of professionals other than ophthalmologists are being proposed to alleviate this pressure. A sound evidence base is imperative to determine whether other allied health professionals are skilled and clinically competent, when it comes to taking on these new roles in glaucoma management.

METHODS

A systematic review of research articles identified in MEDLINE, CINAHL, Embase, Scopus and Cochrane Library was performed. Studies which investigated rater reliability of various health professionals in diagnosing and/or identifying glaucoma progression against a reference standard were included.

RESULTS

Of the 4088 publications identified by the initial database search, 32 met the inclusion criteria. The majority of studies demonstrated positive results, with most finding moderate to substantial agreement for inter- and intra-rater reliability across all testing modalities. The eye health professionals with ophthalmology training consistently attained the greatest agreement. When allied health professionals with different levels of training were compared, those who had completed residency training were significantly better than those who had not.

CONCLUSION

The studies included in this review show promising results, including those raters without ophthalmology training. A lack of power calculations, unequal sample sizes in some studies and the diversity of the testing procedures used make it difficult to make sound inferences.

Visual field loss in primary congenital glaucoma

PURPOSE

To assess the visual field defects in primary congenital glaucoma (PCG) and to identify associated risk factors.

METHODS

In this cross-sectional study visual fields of consecutive PCG patients were examined using Humphery Field Analyzer (HFA) or Goldmann visual field (GVF). All patients had maintained an intraocular pressure (IOP) ≤14 mm Hg on standard care. Mean deviation, pattern standard deviation (PSD), foveal threshold in HFA, and global visual field extent (degrees) in 24 meridians for targets V4e, I4e, I2e in GVF were recorded and evaluated with respect to baseline IOP and age at detection. Statistical analysis was performed by Kruskal Wallis and Mann-Whitney test. Qualitative analysis of GVF and reliable fields in HFA was performed.

RESULTS

A total of 100 eyes of 77 patients were included: 56 eyes of 47 patients were in the HFA group; 44 eyes of 30 patients, in the GVF group. On HFA, mean deviation detected at ≤1 month of age was significantly lower than eyes detected after 1 year (P < 0.001). On GVF, the global visual field extent for target I4e and I2e was significantly lower for PCG detected at ≤1 month of age compared to those seen at >1 year (I4e, P < 0.001; I2e, P = 0.005). Mean deviation, PSD, and foveal threshold were significantly lower in PCG with baseline IOP of >30 mm Hg than with IOP of 20-25 mm Hg (mean deviation, P < 0.001; PSD, P = 0.002; foveal threshold, P = 0.002). Extent for targets V4e and I4e on GVF were significantly lower in patients with baseline IOP of >30 mm Hg compared to those with baseline IOP of 20-25 mm Hg (V4e, P = 0.002; I4e, P = 0.003). Definitive glaucomatous defects were found in 36 eyes (41%), most ommon being arcuate scotoma (19 eyes [22%]).

CONCLUSIONS

PCG detected at age ≤1 month and those having a baseline IOP of >30 mm Hg show greater visual field loss.

Paracentral scotoma in glaucoma detected by 10-2 but not by 24-2 perimetry

PURPOSE

To describe, in glaucomatous patients, spectral-domain optical coherence tomography (SD-OCT) results predictive of paracentral visual field (VF) defects present on standard automated perimetry (SAP) 10-2, but not on SAP 24-2.

METHODS

The SAP 10-2 test was repeated 3 times to determine whether paracentral VF defects were present. Spectralis™ HRA + OCT was used to obtain speckle-noise-reduced macular B-scans. The macular scan protocol consisted of 19 vertical cross-sectional scan lines centered on the fovea (30° × 15° volume scan), each of which was the average of 50 scans. A 3D OCT-2000 was also used to determine macular layer thicknesses and to detect abnormally thin regions (below the 1 % confidence interval of the normative data).

RESULTS

We identified 3 cases in which paracentral VF defects were detected on SAP 10-2, but not on SAP 24-2. Paracentral VF defects were detected on all of the SAP 10-2 tests repeated 3 times, and included absolute scotoma in 2 of the 3 SAP 10-2 results. Retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) damage was diminished on SD-OCT macular images; 2 patients had RNFL and GCL thinning within and central to the parafoveal region, where the GCL is generally thickest in healthy eyes, and 1 patient had evident RNFL and GCL thinning in the papillomacular bundle.

CONCLUSIONS

Macular SD-OCT scans may be useful in deciding whether SAP 10-2 should be performed.

Macular structure parameters as an automated indicator of paracentral scotoma in early glaucoma

PURPOSE

To evaluate the predictive ability of macular parameters defined in the significance map created using spectral-domain optical coherence tomography (SD-OCT) for paracentral visual field defects in early glaucoma.

DESIGN

Prospective comparative study.

METHODS

We studied 78 early-glaucomatous eyes of 78 patients, who underwent SD-OCT and standard automated perimetry 10-2. Macular layer parameters included the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) + inner plexiform layer (IPL), and RNFL + GCL + IPL. The minimal distance between the area with abnormal (P < 1%) thickness and foveal center was defined as the shortest distance. A wider area of an abnormally thinned (<1%) region, within either an inferior or a superior hemicircle with a diameter of 6 mm centered at the fovea, was defined as the macular abnormal area. A circumpapillary RNFL parameter was defined in its 36 sectors. Areas under the receiver operating characteristic curves (ROCs) were calculated to discriminate between eyes with (n = 39) and without (n = 39) paracentral visual field defects in the central 5 degrees.

RESULTS

Measurement reproducibility was almost perfect in the macular parameters at P < 1% (intraclass correlation, 0.907-0.942). Areas under the ROC were significantly higher (P ≤ 0.01) in the macular parameters (0.870-0.930), including the shortest distance of GCL + IPL/RNFL + GCL + IPL, and the macular abnormal area of RNFL/GCL + IPL/RNFL + GCL + IPL than in the circumpapillary RNFL parameter (0.676). When specificity was fixed at ≥90%, the shortest distance of GCL + IPL (area under the ROC = 0.874) and the macular abnormal area of RNFL (area under the ROC = 0.894) showed sensitivities greater than 50%.

CONCLUSIONS

Macular structural parameters defined on an SD-OCT significance map may be potentially useful predictors of the presence of paracentral scotoma.

Measurement of macular ganglion cell layer and circumpapillary retinal nerve fiber layer to detect paracentral scotoma in early glaucoma

BACKGROUND

Glaucoma patients with paracentral scotoma are at higher risk of losing central vision than those without glaucoma. The purpose of this study was to determine whether macular inner retinal layer (MIRL) measurements with spectral-domain optical coherence tomography (SD-OCT) outperform circumpapillary retinal nerve fiber layer (cpRNFL) measurements in discriminating between eyes with and without paracentral scotoma.

METHODS

This retrospective study included 63 early glaucomatous eyes of 63 patients with (PSI group) or without (PSF group) paracentral visual field (VF) defects. MIRL thicknesses, including macular ganglion cell complex (mGCC), macular ganglion cell layer + inner plexiform layer (mGCL+), macular RNFL (mRNFL), and cpRNFL thickness were measured using a SD-OCT instrument (3D OCT-2000). The MIRL and cpRNFL were divided into 50 grid cells and 36 sectors, respectively, which were numbered from center/temporal to periphery/nasal. Discriminating ability of the methods for number of cells/sectors with abnormal thickness (<5% of normal) and average thickness in the hemisphere corresponding to the VF defects (termed hemi-thickness) was compared by area under the receiver operating characteristics curves (AROCs).

RESULTS

The number of abnormal nearest sectors of cpRNFL and all MIRL parameters were significantly smaller in the PSI group than in the PSF group (P ≤ 0.001-0.047), whereas no significant differences were found for average or hemi-cpRNFL thickness. The AROCs of the number of abnormal nearest cells for mGCC and mGCL+ and average hemi-thickness for mGCC, mGCL+, and mRNFL were comparable and significantly higher than those of the number of abnormal nearest sectors/cells for cpRNFL (P = 0.0002-0.0063) and mRNFL (P = 0.0003-0.0267) parameters.

CONCLUSIONS

Regional assessment of MIRL thickness as measured by SD-OCT may potentially be an effective method for predicting central involvement of VF defects in early glaucoma.

Initial arcuate defects within the central 10 degrees in glaucoma

PURPOSE

To better understand the relationship between the spatial patterns of functional (visual field [VF] loss) and structural (axon loss) abnormalities in patients with glaucomatous arcuate defects largely confined to the central 10° on achromatic perimetry.

METHODS

Eleven eyes (9 patients) with arcuate glaucomatous VF defects largely confined to the macula were selected from a larger group of patients with both 10-2 and 24-2 VF tests. Eyes were included if their 10-2 VF had an arcuate defect and if the 24-2 test was normal outside the central 10° (i.e., did not have a cluster of three contiguous points within a hemifield). For the structural analysis, plots of retinal nerve fiber layer (RNFL) thickness of the macula were obtained with frequency-domain optical coherence tomography (fdOCT). The optic disc locations of the RNFL defects were identified on peripapillary fdOCT scans.

RESULTS

The VF arcuate defects extended to within 1° of fixation on the 10-2 test and were present in the superior hemifield in 10 of the 11 eyes. The arcuate RNFL damage, seen in the macular fdOCT scans of all 11 eyes, involved the temporal and inferior temporal portions of the disc on the peripapillary scans.

CONCLUSIONS

Glaucomatous arcuate defects of the macula's RNFL meet the disc temporal to the peak of the main arcuate bundles and produce a range of macular VF defects from clear arcuate scotomas to a papillofoveal horizontal step ("pistol barrel scotoma"). If RGC displacement is taken into consideration, the RNFL and VF defects can be compared directly.

Spatial pattern of glaucomatous visual field loss obtained with regionally condensed stimulus arrangements

PURPOSE

To assess the spatial distribution of glaucomatous visual field defects (VFDs) obtained with regionally condensed stimulus arrangements.

METHODS

Sixty-three eyes of 63 glaucoma subjects were examined with threshold-estimating automated static perimetry (full threshold 4-2-1 dB strategy with at least three reversals) on an automatic campimeter or a full-field perimeter. Stimuli were added by the examiner to regionally enhance spatial resolution in regions that were suspicious for a glaucomatous VFD. These regions were characterized by contiguous local VFDs, attributable to the retinal nerve fiber bundle course according to the impression of the examiner. The added stimulus locations were subsets of a predefined, dense perimetric grid. All VFD locations with P < 0.05 (total deviation plots) were assessed by superimposing the visual field records of all participants.

RESULTS

Glaucomatous VFD loss occurred more frequently in the upper than in the lower hemifield, with a typical retinal nerve fiber-related pattern and a preference of the nasal step region. More than 50% of the eyes with predominantly mild to moderate glaucomatous field loss showed defective locations in the immediate superior paracentral region within an eccentricity of 3°.

CONCLUSIONS

Conventional thresholding white-on-white perimetry with regionally enhanced spatial resolution reveals that glaucomatous visual field loss affects the immediate paracentral area, especially the upper hemifield, in many eyes with only mild to moderate glaucomatous visual field loss. Detailed knowledge about the spatial pattern and the local frequency distribution of glaucomatous VFDs is an essential prerequisite for creating regionally condensed stimulus arrangements for adequate detection and follow-up of functional glaucomatous damage.