Glaucoma detection in Latino population through OCT's RNFL thickness map using transfer learning.

PURPOSE: Glaucoma is the leading cause of irreversible blindness worldwide. It is estimated that over 60 million people around the world have this disease, with only part of them knowing they have it. Timely and early diagnosis is vital to delay/prevent patient blindness. Deep learning (DL) could be a tool for ophthalmologists to give a more informed and objective diagnosis. However, there is a lack of studies that apply DL for glaucoma detection to Latino population. Our contribution is to use transfer learning to retrain MobileNet and Inception V3 models with images of the retinal nerve fiber layer thickness map of Mexican patients, obtained with optical coherence tomography (OCT) from the Instituto de la Visión, a clinic in the northern part of Mexico. METHODS: The IBM Foundational Methodology for Data Science was used in this study. The MobileNet and Inception V3 topologies were chosen as the analytical approaches to classify OCT images in two classes, namely glaucomatous and non-glaucomatous. The OCT files were collected from a Zeiss OCT machine at the Instituto de la Visión, and classified by an expert into the two classes under study. These images conform a dataset of 333 files in total. Since this research work is focused on RNFL thickness map images, the OCT files were cropped to obtain only the RNFL thickness map images of the corresponding eye. This action was carried out for images in both classes, glaucomatous and non-glaucomatous. Since some images were damaged (with black spots in which data was missing), these images were cut-out and cut-off. After the preparation process, 50 images per class were used for training. Fifteen images per class, different than the ones used in the training stage, were used for running predictions. In total, 260 images were used in the experiments, 130 per eye. Four models were generated, two trained with MobileNet, one for the left eye and one for the right eye, and another two trained with Inception V3. TensorFlow was used for running transfer learning. RESULTS: The evaluation results of the MobileNet model for the left eye are, accuracy: 86%, precision: 87%, recall: 87%, and F1 score: 87%. The evaluation results of the MobileNet model for the right eye are, accuracy: 90%, precision: 90%, recall: 90%, and F1 score: 90%. The evaluation results of the Inception V3 model for the left eye are, accuracy: 90%, precision: 90%, recall: 90%, and F1 score: 90%. The evaluation results of the Inception V3 model for the right eye are, accuracy: 90%, precision: 90%, recall: 90%, and F1 score: 90%. CONCLUSION: In average, the evaluation results for right eye images were the same for both models. The Inception V3 model showed slight better average results than the MobileNet model in the case of classifying left eye images.

Study of inelastic mean free path of metal nanostructures using energy filtered transmission electron microscopy imaging.

We report a simple method for measuring the inelastic mean free path of nanostructures of known geometry using energy filtered transmission electron microscopy imaging. The mean free path of inelastic electrons was measured by using systems having known symmetry, such as cylindrical or cubic, combined with Poisson statistics without employing the knowledge of microscope parameters, namely the convergence angle and the collection angle. Having inherent symmetry of such systems, their absolute thickness can be measured from their two-dimensional projection images. We have calculated mean free path of inelastic scattering of electrons in gold, silver and nickel doing case study research by employing gold nanorod, silver nanocube and nickel nanorod lying on a carbon-coated TEM grid at two different electron energies (viz. 200 and 300 keV) following this alternative approach. Results obtained using such alternative approach were verified using microscope parameters.

Widefield swept source optical coherence tomography for the monitoring of choroidal infiltrates.

Choroidal Infiltrates (Cis) detection is traditionally done using invasive imaging. We herein report the usage of topographic choroidal thickness maps (ChT maps) and en face swept-source Optical Coherence Tomography (OCT) as a rapid and non-invasive technique to monitor Cis in a patient with Chronic Lymphocytic Leukemia.

Thickness mapping of the inner retina by spectral-domain optical coherence tomography in an N-methyl-D-aspartate-induced retinal damage model.

Spectral-domain optical coherence tomography (SD-OCT) is an interferometric optical tomography technique and provides high resolution and noninvasive visualization of retinal morphology. The purpose of this study was to assess the utility of thickness maps and quantitative thickness measurements of the ganglion cell complex (GCC: retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer) obtained by SD-OCT of a mouse model of N-methyl-d-aspartate (NMDA)-induced retinal damage. SD-OCT imaging was performed in ddY mice at 1, 3, and 7 days and 1 month after intravitreal injection of NMDA. GCC thickness maps and circle cross-sectional OCT images were made from volumetric OCT images. The GCC thickness was measured on a cross-sectional OCT image on a circle with a radius 300 µm from the center of the optic nerve disc. Histological analysis was conducted by measuring the GCC thickness at the same time intervals. The thickness maps and the quantitative thickness values of GCC showed thickness changes at each time point in the NMDA-treated mice when compared with normal and vehicle-treated mice. Both the OCT sectional images and the histological images revealed increases in GCC thickness at 1 day, followed by decreases from 3 days to 1 month after NMDA injection. The GCC thickness measured using OCT sectional images correlated with the thickness measured using histological images. In conclusion, GCC thickness mapping is a useful method for evaluating NMDA-induced retinal degeneration in mice.

Diagnostic value of 3D Optical Coherence Tomography Multimode Images in the Diagnosis of Acute Central Serous Chorioretinopathy.

BACKGROUND: Spectral-Domain Optical Coherence Tomography (SD-OCT) provides non-invasive, high-speed, high-resolution, three-dimensional cross-section imaging of the macula. OBJECTIVES: This study aimed to investigate the diagnostic value of the multimodal imaging technique of three-dimension (3D) optical coherence tomography (OCT) (3D-OCT) for the diagnosis and characterization of acute central serous chorioretinopathy (CSC). METHODS: In this prospective clinical study 3D-OCT examinations of 82 cases with acute CSC were performed on the macular area, and the image characteristics were analyzed. Our study included a total of 87 eyes from 82 cases of CSC patients, 67 males and 15 females (mean age ± standard deviation (SD): 42.89 ±7.80 years old; age range: 27 to 56 years old. The 3D-OCT images were evaluated for the presence of subretinal fluid, subretinal space, fluctuation of the internal limiting membrane (ILM), folds of retinal pigment epithelial (RPE), retinal pigment epithelium detachment (PED), and flat irregular PED. The foveal thickness was measured using the manual caliper of OCT software. RESULTS: The OCT B-scan images showed 87 (100%) eyes had exudative retinal detachment (ERD), 38 (44%) had flat irregular PED, 36 (41%) had PED, 8 (9%) had subretinal turbidity structure, 2 (2%) had subretinal dot-like precipitates, 1 (1%) had focal choroidal excavation (FCE), and 1 (1%) eye had fluctuation of internal limiting membrane (FI). In the ILM-RPE thickness map, all eyes had a round or round like regular uniform domes. Fifty-seven (66%) domes were limited in the examination area and 30 (44%) domes were beyond the scope of this examination and only a partial section of the dome could be observed. In the en-face image, all eyes had a round or round-like black figure that corresponded with domes in the ILM-RPE thickness map. In RPE surface, 76 (87%) eyes had a shallow plate depression, 71(82%) had small focal uplift, and 1 (1%) eye had a focal concave feature. CONCLUSIONS: In the OCT ILM-RPE thickness, en-face image, and RPE surface maps, acute CSC exhibited specific imaging characteristics that can be helpful for reliable diagnosis and differential diagnosis of CSC.

Three-dimensional ultrasound assessment of effects of therapies on carotid atherosclerosis using vessel wall thickness maps.

We present a new method for assessing the effects of therapies on atherosclerosis, by measuring the weighted average of carotid vessel-wall-plus-plaque thickness change (ΔVWT¯Weighted) in 120 patients randomized to pomegranate juice/extract versus placebo. Three-dimensional ultrasound images were acquired at baseline and one year after. Three-dimensional VWT maps were reconstructed and then projected onto a carotid template to obtain two-dimensional VWT maps. Anatomic correspondence on the two-dimensional VWT maps was optimized to reduce misalignment for the same subject and across subjects. A weight was computed at each point on the two-dimensional VWT map to highlight anatomic locations likely to exhibit plaque progression/regression, resulting in ΔVWT¯Weighted for each subject. The weighted average of VWT-Change measured from the two-dimensional VWT maps with correspondence alignment (ΔVWT¯Weighted,MDL) detected a significant difference between the pomegranate and placebo groups (P = 0.008). This method improves the cost-effectiveness of proof-of-concept studies involving new therapies for atherosclerosis.

Swept-source optical coherence tomography objective composite activity score for uveitis.

PURPOSE: To develop an objective intraocular inflammation composite score. METHODS: Cross-sectional study. Non-invasive image acquisition and processing were conducted from April 2017 to April 2019. Inflammation-grade stratified eyes from patients with active, inactive uveitis and healthy controls were recruited. After clinical assessment, four anterior and posterior segment image acquisition protocols per eye, using swept-source optical coherence tomography (SS-OCT), were performed at inclusion. Eight imaging biomarkers in three domains: anterior, intermediate and posterior were studied. They were ranked and selected by discriminatory power and correlation with clinical scores. A final SS-OCT-derived composite uveitis activity score (SS-UAS) was developed through multiple linear regression. RESULTS: We studied 224 eyes with uveitis (165 active and 59 inactive) from 165 patients (mean age 46.6 SD 15.5 years; 55.3% women) and 38 eyes from 19 healthy controls (mean age 43.6 SD 17.1; 47% women). The selected SS-OCT-derived biomarkers to build the final score were anterior chamber hyper-reflective dots (anterior), high-definition relative vitreous intensity (intermediate) and the averaged thickened retinal index (posterior). Swept-source (SS)-UAS was highly discriminant between active and inactive, and between active and healthy eyes (means 2.06 SD 1.86, 0.93 SD 0.44, and 0.96 SD 0.38, respectively, both p -, Mann-Whitney U). Construct validity (Cronbach's alpha = 0.7), internal consistency, criterion validity and reliability (concordance correlation coefficient intra-rater = 0.99, 95% CI: 0.98-0.99; inter-rater = 0.98, 95% CI: 0.96-0.99) were favourable. CONCLUSIONS: Global intraocular inflammation can potentially be staged and scored objectively, continuously, consistently and in a valid manner through the combined processing of SS-OCT scans.

Large-cube 30° × 25° optical coherence tomography in diabetic macular edema.

BACKGROUND: To evaluate the contribution of large-cube 30° × 25° optical coherence tomography (OCT) in the characterization of diabetic macular edema (DME) by assessing its extent and the presence of additional retinal edemas and to evaluate the factors that influenced their occurrence. METHODS: This retrospective study enrolled patients with diabetes who presented with retinal edema detected by horizontal large-cube 30° × 25° (8.7 × 7.3 mm) OCT. Two individualized areas were selected from the thickness map: the area within the 6-mm Early Treatment of Diabetic Retinopathy Study (ETDRS) grid, and that outside the ETDRS grid. Retinal edemas located within the ETDRS grid were designated as "main DME" and those located outside the ETDRS grid were designated as "peripheral retinal edemas." For each area, OCT features were assessed while the extent of the main DME and the presence of peripheral retinal oedema were analysed in the area outside the ETDRS grid. Finally, part of included eyes was followed by the same protocol, of which a part benefited from intravitreal injections. RESULTS: Peripheral events were detected outside the ETDRS area in 279 eyes (74.4%) of the 375 eyes of the 218 patients included in this study: an extension of the main DME outside ETDRS grid in 177 eyes (47.2%) and/or the presence of peripheral retinal edemas in 207 eyes (55.2%). The analysis of associations between main DME and peripheral retinal edemas patterns did not find an association for retinal cyst localization (P = 0.42) while a week association was found fort cyst size (Cramer's V = 0.188, p = 0.028). Nevertheless, a moderate association was found for the presence of microaneurysms (Cramer's V = 0.247, p < 0.001) and strong association for hard exudates (Cramer's V = 0.386, p < 0.001), The binary logistic regression analysis retained the following influencing factors of the occurrence of peripheral events: advanced DR stage (Odds ratio OR = 2.19, p = 0.03), diffuse DME (OR = 7.76, p < 0.001) and its location in outer fields (OR = 7.09, p = 0.006). Likewise, the extension of the main DME outside the ETDRS area in was influenced by the same factors in addition to CMT (OR = 0.98, p = 0.004) while the presence of peripheral retinal edema was influenced by the same factors except the outer location of the Main DME. Finally, from the 94 eyes treated by intravitreal injections, extension of the main DME outside the ETDRS grid was detected in 54 eyes (56.44%) at baseline visit and still remained detectable in 37 eyes (39.36%) after treatment initiation. CONCLUSIONS: Large-cube 30° × 25° OCT allowed for more precise assessment of DME extension and better detection of retinal thickening mainly in the advanced stages of diabetic retinopathy with significant DME whether at the baseline visit or during follow-up. The combination of this protocol with a wider ETDRS grid would enhance DME detection and topography.

Comparison of corneal epithelial thickness profile in dry eye patients, keratoconus suspect, and healthy eyes.

PURPOSE: To compare the corneal epithelial thickness profile in patients with dry eyes and keratoconus suspect with normal healthy eyes. METHODS: The study involved 120 eyes with an age range from 19 to 30 years. Forty eyes had normal corneal topography and no dry eyes. Forty eyes had dry eyes but had normal corneal topography. The last 40 eyes were keratoconus suspect and had no symptoms or signs of dry eyes. RESULTS: Central epithelial thickness was not different statistically for all eyes. (p-value: 0.1). The superior epithelial thickness was 53.5 µm ±3.1 in the control group, 53.4 µm ±3.5 in the dry eye group, and 53.6 µm ±2.8 in the keratoconus suspect group. No statistically significant difference was found (p-value = 0.7). The inferior epithelial thickness was 55.7 µm ±3.5 in the control, 57.2 µm ±3.19 in the dry eyes, and 52.2 µm ±3.12 in the KC suspects. There was inferior thickening in the dry eyes and thinning in the KC suspects and this was statistically significant (p-value < 0.01). Minimum epithelial thickness was 52.8 µm ±2.91 in the control and 53.2 µm ±3.51 in the dry eyes and it was located superiorly for both groups. In the KC suspects, the minimum thickness was 52.3 µm ±3.19 and was located inferiorly. CONCLUSION: In our study the epithelium appears to be thicker inferiorly in dry eyes and thinner in KC suspects. Displacement of thinnest location on epithelial map may be a helpful early sign of keratoconus. However, follow-up study is necessary to confirm the thinnest location displacement helped in this diagnosis.

Correlation of corneal pigmented arc with wide epithelial thickness map in orthokeratology-treated children using optical coherence tomography measurements.

PURPOSE: To determine the intensity of corneal pigmented arc in orthokeratology (ortho-k)-treated children and its correlation with wide epithelial thickness map (ETM) obtained through anterior segment optical coherent tomography (AS-OCT). METHODS: This retrospective case series reviews medical records of children who received ortho-k treatment for myopia control. Intensity of ortho-k-associated pigmented arc after wearing ortho-k lens more than 12 months and its correlation with each sector/zone of wide ETM obtained by AS-OCT was explored. Pigmented arcs were further divided into apparent and unapparent groups, and the clinical differences between groups were determined. RESULTS: This study included 57 eyes of 29 children (mean age, 11.4 years, range 9-15); after initiating ortho-k treatment, the incidence of the corneal pigmented arc was 91.2% with mean lens wear duration of 26.1 months. Intensity of pigmented arc was significantly correlated with lens wear duration, target power, baseline degree of myopia, C zone and sectors I2, I3 and IT3 on wide ETM. Comparison between apparent and unapparent groups showed the same significant results except for C zone. After adjusting for lens wear duration and target power, sector I2 has the highest association with pigmented arc severity. CONCLUSION: Children treated with ortho-k are likely to develop ortho-k-associated pigmented arcs. The new wide ETM of AS-OCT can provide important information regarding the intensity of pigmented arc in these children. This can support customized pigmented arc-free ortho-k treatment for children in the future.

[Progressive loss of vision in cone dystrophy. Search for evidence with macular OCT and multifocal ERG]. / Progressive Visusminderung bei Zapfendystrophie. Spurensuche im Makula-OCT und Multifokal-ERG.

A 53-year-old patient consulted our practice clinic complaining of progressive visual loss, increased glare sensitivity and color sense disorder. Extensive diagnostic investigation, including multifocal ERG (mfERG) and macular thickness map with the help of optical coherence tomography (OCT), supported the suspected diagnosis of a cone dystrophy. There are, however, no established therapeutic options. A diagnostic confirmation by means of molecular genetics was not successful.

Comparison of Corneal Epithelial Thickness Map Measured by Spectral Domain Optical Coherence Tomography in Healthy, Subclinical and Early Keratoconus Subjects.

The aim of this study was to compare epithelial thickness map obtained by Spectral Domain Optical Coherence Tomography (SD-OCT) of eyes with myopic astigmatism but without keratoconus, subclinical and early keratoconus. Sixty-three eyes were divided into three groups; myopic astigmatism without keratoconus, subclinical and early keratoconus. Corneal epithelial thickness map was obtained by SD-OCT for all patients and compared between the 3 groups. Mean ± Standard Deviation of epithelial thickness in the area of minimum corneal epithelial thickness, in the one eighth part of the inferior (I) and in the one eighth part of the temporal (T) were 56.64±2.82 µm, 59.00±3.24 µm and 60.40±4.93 µm respectively in subclinical group. Three parameters on epithelial maps obtained by SD-OCT was significantly different in the 2 groups: I and T corneal epithelial thickness map was thicker in subclinical keratoconus (P<0.02 and P<0.02 respectively). Epithelial map uniformity indices were different between the groups, as Superior-I, Superonasal-Inferotemporal were lower (P<0.00 and P< 0.01 respectively) but T-nasal was higher in the subclinical group (P<0.02). The area with minimum epithelial thickness had a significantly lower amount in early keratoconus group compared to the other two groups (P<0.00). In conclusion, corneal epithelial thickness map provided early detection of keratoconus in the subclinical stage with compensatory epithelial thickening of inferior and one eighth of temporal compared to total corneal thickness and changes in epithelial map uniformity indices may lead to early detection of subclinical keratoconus from normal cornea.

Characterization of the coating and tablet core roughness by means of 3D optical coherence tomography.

This study demonstrates the use of optical coherence tomography (OCT) to simultaneously characterize the roughness of the tablet core and coating of pharmaceutical tablets. OCT is a high resolution non-destructive and contactless imaging methodology to characterize structural properties of solid dosage forms. Besides measuring the coating thickness, it also facilitates the analysis of the tablet core and coating roughness. An automated data evaluation algorithm extracts information about coating thickness, as well as tablet core and coating roughness. Samples removed periodically from a pan coating process were investigated, on the basis of thickness and profile maps of the tablet core and coating computed from about 480,000 depth measurements (i.e., 3D data) per sample. This data enables the calculation of the root mean square deviation, the skewness and the kurtosis of the assessed profiles. Analyzing these roughness parameters revealed that, for the given coating formulation, small valleys in the tablet core are filled with coating, whereas coarse features of the tablet core are still visible on the final film-coated tablet. Moreover, the impact of the tablet core roughness on the coating thickness is analyzed by correlating the tablet core profile and the coating thickness map. The presented measurement method and processing could be in the future transferred to in-line OCT measurements, to investigate core and coating roughness during the production of film-coated tablets.

Extraction of the Polyurethane Layer in Textile Composites for Textronics Applications Using Optical Coherence Tomography.

This article presents a new method for the extraction and measurement of the polyurethane layer of Cordura textile composites using optical coherence tomography. The knowledge of coating layer properties in these composites is very important, as it affects mechanical parameters such as stiffness and bending rigidity. Unlike microscopic measurements, which require cross-section samples of the material, the proposed approach is non-invasive. The method is based on detecting the top and bottom boundaries of the polyurethane layer in Optical Coherence Tomography (OCT) images using image processing methods, namely edge enhancement filtering, thresholding and spline smoothing. The cover layer measurement results obtained from a three-dimensional OCT image of the composite fabric are presented as the thickness maps. The average values of the layer thicknesses measured with the OCT method for four types of Cordura showed a high correlation with the results obtained from microscopic measurements (Pearson correlation coefficient r = 0.9844 ), which confirms the accuracy of the OCT method.

Nerve Fiber Flux Analysis Using Wide-Field Swept-Source Optical Coherence Tomography.

PURPOSE: To devise a method to quantify nerve fibers over their arcuate courses over an extended peripapillary area using optical coherence tomography (OCT). METHODS: Participants were imaged with 8 × 8-mm volumetric OCT scans centered at the optic disc. A new quantity, nerve fiber flux (NFF), represents the cross-sectional area transected perpendicular to the nerve fibers. The peripapillary area was divided into 64 tracks with equal flux. An iterative algorithm traced the trajectory of the tracks assuming that the relative distribution of the NFF was conserved with compensation for fiber connections to ganglion cells on the macular side. Average trajectory was averaged from normal eyes and use to calculate the NFF maps for glaucomatous eyes. The NFF maps were divided into eight sectors that correspond to visual field regions. RESULTS: There were 24 healthy and 10 glaucomatous eyes enrolled. The algorithm converged on similar patterns of NFL tracks for all healthy eyes. In glaucomatous eyes, NFF correlated with visual field sensitivity in the arcuate sectors (Spearman ρ = 0.53-0.62). Focal nerve fiber loss in glaucomatous eyes appeared as uniform tracks of NFF defects that followed the expected arcuate fiber trajectory. CONCLUSIONS: Using an algorithm based on the conservation of flux, we derived nerve fiber trajectories in the peripapillary area. The NFF map is useful for the visualization of focal defects and quantification of sector nerve fiber loss from wide-area volumetric OCT scans. TRANSLATIONAL RELEVANCE: NFF provides a cumulative measure of volumetric loss along nerve fiber tracks and could improve the detection of focal glaucoma damage.

Automated detection of foveal center in SD-OCT images using the saliency of retinal thickness maps.

PURPOSE: To develop an automated method based on saliency map of the retinal thickness map to determine foveal center in spectral-domain optical coherence tomography (SD-OCT) images. METHODS: This paper proposes an automatic method for the detection of the foveal center in SD-OCT images. Initially, a retinal thickness map is generated by considering the axial distance between the internal limiting membrane (ILM) and the Bruch's membrane (BM). Both the ILM and BM boundaries are automatically segmented by a known retinal segmentation technique. The macular foveal region is identified as a salient feature in the retinal thickness map, and segmented by the saliency detection method based on a human vision attention model. Finally, the foveal center is identified by searching for the lowest point from the determined macular fovea region. RESULTS: Experimental results in 39 scans from 35 healthy eyes and 58 scans from 29 eyes diagnosed with several stages of age-related macular degeneration (AMD), from mild or intermediate stages to severe dry or wet stages, demonstrated that the proposed method achieves good performance. The mean radial distance error of the automatically detected foveal center locations when compared to consensus manual determination established by repeated sessions from two expert readers was 52 ± 56 µm for the normal eyes and 73 ± 63 µm for AMD eyes. CONCLUSIONS: The proposed algorithm was more effective for detecting the foveal center automatically in SD-OCT images than the state-of-art methods.

Adjunctive use of systematic retinal thickness map analysis to monitor disease activity in punctate inner choroidopathy.

A challenge in the management of 'white dot syndromes' is the lack of sensitive objective measures of disease activity. Retinal thickness maps from spectral domain optical coherence tomography (SD-OCT) inform treatment decisions in other retinal conditions such as age-related macular degeneration and diabetic maculopathy. In this report, we demonstrate their value in providing quantitative monitoring of a patient with punctate inner choroidopathy (PIC). Retinal thickness maps referenced against a baseline scan reliably detected focal areas of increased macular volume in active PIC lesions during symptomatic episodes, highlighting these as 'hot spots' that could be quantified, providing an objective basis for treatment decisions.

Diffuse retinal nerve fiber layer defects identification and quantification in thickness maps.

PURPOSE: To report retinal nerve fiber layer (RNFL) defect identification and quantification in RNFL thickness maps according to the structural RNFL loss, and to evaluate diffuse RNFL defects. METHODS: A total of 170 patients with glaucoma and 186 normal subjects were consecutively enrolled. We defined RNFL defects in an RNFL thickness map by the degree of RNFL loss. The reference level for RNFL defect determination was set as a 20% to 70% degree of RNFL loss with a 1% interval. To identify RNFL defects, each individual RNFL thickness map was compared to the normative database map by using MATLAB software, and the region below the reference level was detected. The area, volume, location, and angular width of each RNFL defect were measured. Diffuse RNFL defects were defined as having an angular width > 30°. RESULTS: The optimal reference level for glaucomatous RNFL defects identification was 42% loss of RNFL. Retinal nerve fiber layer defects were identified in all (100%) of the 170 glaucoma patients and false-positive RNFL defects were detected in 16 (8.16%) cases among the 186 normal subjects. In all, 64.1% of glaucoma patients had diffuse RNFL defects, and 47.7% of diffuse RNFL defects were associated with mild glaucoma patients. The volume of diffuse RNFL defects was significantly associated with the severity of glaucomatous damage (P = 0.009). Diffuse RNFL defects were located closer to the center of the optic disc than localized RNFL defects (P < 0.001). CONCLUSIONS: Retinal nerve fiber layer thickness map analysis is an effective method for analyzing RNFL defects. Quantitative measurements (area, volume, location, and width) were useful to understanding diffuse RNFL defects.

Assessment of macular ganglion cell loss patterns in neurologic lesions that mimic glaucoma.

PURPOSE: To evaluate patterns of macular retinal ganglion cell (RGC) loss measured by spectral domain optical coherence tomography in patients with neurologic lesions mimicking glaucoma. METHODS: We evaluated four patients with neurological lesions who showed characteristic patterns of RGC loss, as determined by ganglion cell thickness (GCT) mapping. RESULTS: Case 1 was a 30-year-old man who had been treated with glaucoma medication. A left homonymous vertical pattern of RGC loss was observed in his GCT map and a past brain magnetic resonance imaging (MRI) revealed a hemorrhagic lesion around the right optic radiation. Case 2 was a 72-year-old man with a pituitary adenoma who had a binasal vertical pattern of RGC loss that corresponded with bitemporal hemianopsia. Case 3 was a 77-year-old man treated for suspected glaucoma. His GCT map showed a right inferior quadratic pattern of loss, indicating a right superior homonymous quadranopsia in his visual field (VF). His brain MRI revealed a left posterior cerebral artery territory infarct. Case 4 was a 38-year-old woman with an unreliable VF who was referred for suspected glaucoma. Her GCT map revealed a left homonymous vertical pattern of RGC loss, which may have been related to a previous head trauma. CONCLUSIONS: Evaluation of the patterns of macular RGC loss may be helpful in the differential diagnosis of RGC-related diseases, including glaucoma and neurologic lesions. When a patient's VF is unavailable, this method may be an effective tool for diagnosing and monitoring transneuronal retrograde degeneration-related structural changes.

Assessment of Macular Ganglion Cell Loss Patterns in Neurologic Lesions That Mimic Glaucoma

PURPOSE: To evaluate patterns of macular retinal ganglion cell (RGC) loss measured by spectral domain optical coherence tomography in patients with neurologic lesions mimicking glaucoma. METHODS: We evaluated four patients with neurological lesions who showed characteristic patterns of RGC loss, as determined by ganglion cell thickness (GCT) mapping. RESULTS: Case 1 was a 30-year-old man who had been treated with glaucoma medication. A left homonymous vertical pattern of RGC loss was observed in his GCT map and a past brain magnetic resonance imaging (MRI) revealed a hemorrhagic lesion around the right optic radiation. Case 2 was a 72-year-old man with a pituitary adenoma who had a binasal vertical pattern of RGC loss that corresponded with bitemporal hemianopsia. Case 3 was a 77-year-old man treated for suspected glaucoma. His GCT map showed a right inferior quadratic pattern of loss, indicating a right superior homonymous quadranopsia in his visual field (VF). His brain MRI revealed a left posterior cerebral artery territory infarct. Case 4 was a 38-year-old woman with an unreliable VF who was referred for suspected glaucoma. Her GCT map revealed a left homonymous vertical pattern of RGC loss, which may have been related to a previous head trauma. CONCLUSIONS: Evaluation of the patterns of macular RGC loss may be helpful in the differential diagnosis of RGC-related diseases, including glaucoma and neurologic lesions. When a patient's VF is unavailable, this method may be an effective tool for diagnosing and monitoring transneuronal retrograde degeneration-related structural changes.