Optical Coherence Tomography In Eyes Research Articles

Comparison of Automated and Manual Measurement of Corneal Epithelial Thickness in Eyes With Limbal Stem Cell Deficiency.

The purpose of this study was to compare the outcomes of manual and automated corneal epithelial thickness (CET) assessments using anterior segment optical coherence tomography in eyes with limbal stem cell deficiency (LSCD). Eighty-seven eyes from 64 patients with LSCD and 65 eyes from 39 healthy subjects were included in this cross-sectional study. OCT images of corneas were acquired using a Fourier-domain anterior segment optical coherence tomography. The automated measurement of CET was obtained using the manufacturer's program and the manual measurements were obtained by 2 masked observers. The average CET was obtained from 3 consecutive epithelial profile maps. The average CET of manual measurement was obtained from 3 consecutive cross-line scans using 3-point measurement as previously described. The central CET was thinner in patients with LSCD compared with healthy individuals by both manual and automated measurements. Automated CET measurements were similar to the manually obtained CET in the healthy controls (r = 0.911). However, there is a lower correlation between the automated and manually obtained CET in the LSCD group (r = 0.497). Manual measurements of CET (39.8 ± 11 μm) in eyes with LSCD were significantly lower than the automated measurements (48.8 ± 7.2 μm, P = 0.001, 95% CI -11.0 to -6.9). The correlations between the automated and manually obtained measurements in the mild, moderate, and severe stages of LSCD were 0.623, 0.632, and 0.378, respectively. There is a large discrepancy between the manual and automated measurements in eyes with LSCD but not in normal eyes. Automated measurements in LSCD exhibited a higher rate of errors and nonuniform measurements due to the presence of subepithelial scars. Automated CET measurements appear to be unreliable in eyes with corneal scars in LSCD.

Quantifying Changes on OCT in Eyes Receiving Treatment for Neovascular Age-Related Macular Degeneration

PurposeApplication of artificial intelligence (AI) to macular optical coherence tomography (OCT) scans to segment and quantify volumetric change of anatomical and pathological features during intravitreal treatment for neovascular age-related macular degeneration (AMD). DesignRetrospective analysis of OCT images from the Moorfields Eye Hospital AMD Database. Participants2115 eyes from 1883 patients that started anti-vascular endothelial growth factor (anti-VEGF) treatment between 1st June 2012 and 30th June 2017. MethodsThe Moorfields Eye Hospital neovascular AMD database was queried for first and second eyes that received anti-VEGF treatment and had an OCT scan at baseline and at 12 months. Follow-up scans were input into the AI system to derive volumetric outputs for the following variables: intraretinal fluid (IRF), subretinal fluid (SRF), pigment epithelial detachment (PED), subretinal hyperreflective material (SHRM), hyperreflective foci (HRF), neurosensory retina (NSR) and retinal pigment epithelium (RPE). Volumes were studied at different time points and comparisons made with respect to baseline volume groups. Cross-sectional comparisons between time points were conducted using Mann-Whitney U test. ResultsMean volumes of analysed features decreased significantly from baseline to both four and 12 months, in both first and second-treated eyes. Pathological features that reflect exudation, including pure fluid components (IRF and SRF) and those with a mixture of fluid and fibrovascular tissue (PED and SHRM), displayed similar response to treatment over 12 months. Mean PED and SHRM volumes showed less pronounced but also substantial decreases over the first two months, reaching a plateau post loading phase, and minimal change to 12 months. Both NSR and RPE volumes showed gradual reductions over time, and not as substantial as exudative features. Conclusion:We report the results of a quantitative analysis of change in retinal segmented features over time, enabled by an AI segmentation system. Cross-sectional analysis at multiple time points demonstrated significant associations between baseline OCT-derived segmented features and the volume of biomarkers at follow-up. Demonstrating how certain OCT biomarkers progress with treatment and the impact of pre-treatment retinal morphology on different structural volumes may provide novel insights into disease mechanisms and aid personalization of care. Data will be made public for future studies.

Central Bouquet Hemorrhages in Pathologic Myopia: Clinical Characteristics and Prognostic Relevance

To compare the clinical implications of central bouquet hemorrhages (CBH) to primarily subretinal hemorrhages, both occurring in the setting of pathologic myopia with lacquer crack formation. Multi-center retrospective cohort study PARTICIPANTS: 25 eyes (11 primarily subretinal hemorrhages, 14 CBH) were monitored over a median of 35 months (interquartile range [IQR] 9.50-54). Comprehensive ophthalmological examinations and optical coherence tomography (OCT) were reviewed. The study employed linear mixed-effects models to compare the impact of CBH versus primarily subretinal hemorrhages on baseline visual acuity (VA), rate of VA improvement, and final VA, adjusting for the follow-up period. Times of hemorrhages reabsorbtion and rate of ellipsoid zone (EZ) layer disruption on OCT were recorded. Eyes with CBH exhibited significantly worse baseline VA (0.93±0.45[20/160 Snellen] vs. 0.36±0.26[20/50 Snellen] LogMAR, p<0.001), a slower rate of VA improvement (p=0.04), and a trend towards worse final VA (0.48±0.47[20/60 Snellen] vs. 0.16±0.16[20/30 Snellen] LogMAR, p=0.06) compared to eyes with primarily subretinal hemorrhages. The CBH group experienced prolonged reabsorption times (median 10 months [IQR 4.6-23.3] vs. 2.3 months [IQR 2-3.2]) and a high prevalence of EZ layer disruption (86% vs. 0%) than primarily subretinal hemorrhages. CBH reabsorption was followed by the appearance of vertical hyperreflective lines in the central fovea in 67% of eyes, persisting for up to 6 years of follow-up. CBH signifies a distinct condition in pathologic myopia, characterized by worse visual outcomes, prolonged structural impact, and possible irreversible damage, compared to primarily subretinal hemorrhages. CBH regression should be taken into account in the differential diagnosis of vertical hyperreflective lesions in the central fovea on OCT in eyes with pathologic myopia.

Optical coherence tomography and shear wave elastography findings in Graves ophthalmopathy.

The main feature of Graves ophthalmopathy (GO) is revealed by determining the activity and severity of the disease. We aimed to evaluate the use of imaging methods can also provide additional information about the severity of this disease. Optical coherence tomography (OCT) and shear wave elastography (SWE) findings were compared in 32 patients with mild GO group and in the healthy control group. Measuring for TSH receptor antibody (TRAb) serum level is used third-generation assay. In Graves group, optic nerve sheath diameter (ONSD) values were increased in both eyes (p < 0.001, p < 0.001). SWE measurements showed a significant increase both eye optic nerve (ON) and right eye soft tissue elasticity values in GO group (p < 0.001, p < 0.001, p < 0.001, respectively). There was a significant thinning in left temporal retinal nerve fiber layer (RNFL) thickness and left RNFL peripapillary thickness in GO group (p < 0.001, p < 0.025, respectively). There was a correlation between left eye OCT and SWE findings. Also, there was a significant difference between the median left eye ON and soft tissue elasticity results in the TRAb-positive GO group (p = 0.049, p = 0.048, respectively). SWE measurements showed a significant increase both eyes ONSD, ON and right eye soft tissue elasticity values in GO group. GO group was significant thinning in some left eye regions in OCT measurements. There was a correlation between left eye OCT and SWE findings. In addition to clinical activity score and TRAb, SWE and OCT can be used to monitor in patients with GO.

Evaluation of Retinal Layers in Individuals With Pseudoexfoliation Syndrome and Ocular Hypertension.

This study investigated the retinal segmental thicknesses in individuals with pseudoexfoliation syndrome and ocular hypertension. Maximum thinning was found at 6 mm inferior to the inner plexiform layer. This layer is very important for the early diagnosis of glaucoma. To analyze the thickness of the peripapillary retinal nerve fiber layer and 8 macular layers using optical coherence tomography in eyes with ocular hypertension (OHT) and pseudoexfoliation syndrome (PXS) and healthy eyes and to evaluate between-group differences. In a prospective study, the macular segmentation of retinal layers in 120 eyes of 120 participants was performed automatically using current Heidelberg Spectralis optical coherence tomography software, which provides measurements for 8 retinal layers. Thickness maps divided into nine subfields (ie, 1, 3, and 6mm) were extracted from the software for each retinal layer and compared between groups. The thinnest macular layers appeared in the ocular hypertensive PXS, normotensive PXS, and OHT groups in that order. In the inner retinal layers (macular retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer), statistically significant differences emerged between the PXS and control groups in all quadrants of the 3 and 6mm areas. No significant difference between the OHT group and control group appeared except in the 6mm temporal quadrant of the inner plexiform layer (IPL). Receiving operating characteristic analysis revealed quadrants with high area-under-the-curve values at 3 and 6mm in macular segments in all 3 groups compared with the control group. In macular segment analysis, the inner retinal layers showed the most thinning in patients with ocular hypertensive PXS. According to receiving operating characteristic curve analysis, examinations performed 6mm inferior to the IPL, as the quadrant with the highest area under the curve in all 3 groups, are critical for the early diagnosis of glaucoma.

Agreement, repeatability, and reproducibility of quantitative retinal layer assessment using swept-source and spectral-domain optical coherence tomography in eyes with retinal diseases.

To evaluate the agreement and precision of retinal thickness measurements obtained using swept-source optical coherence tomography (SS-OCT) and spectral-domain OCT (SD-OCT) in healthy eyes and eyes with retinopathy. This cross-sectional prospective study involved three DRI-OCT Triton (SS-OCT) and three 3D-OCT-1 Maestro (SD-OCT) devices. One of each device (Maestro and Triton) was paired with a single operator. Healthy subjects and patients with retinal diseases were recruited, with study eye and testing order randomized. At least 3 scans per eye were captured for wide scan (12 mm × 9 mm-Triton and Maestro) and macular cube scan (7 mm × 7 mm-Triton, 6 mm × 6 mm-Maestro). Thickness of the full retina, ganglion cell layer + inner plexiform layer (GCL+), and ganglion cell complex (GCL++) were obtained from wide scan and cube scans. Agreement of the measurements between the Triton and Maestro was evaluated by Bland-Altman analysis and Deming regression for each group. Repeatability and reproducibility were assessed using a two-way random effect analysis of variance (ANOVA) model for each parameter by group. Twenty-five healthy subjects (25 eyes) and 26 patients with retinal diseases (26 eyes), including, but not limited to, age-related macular degeneration, macular hole, and diabetic retinopathy were recruited. Overall, the measurement differences between Triton and Maestro were <6 μm (mean differences of full retina, GCL++, and GCL+ thickness were ≤5.5 μm, 1.3 μm, and 2.8 μm, respectively) and not statistically significant across the parameters. The repeatability and reproducibility estimates indicate high precision in both devices and groups. Across all the parameters, the repeatability limit was ≤7.6 μm for Triton and ≤12.7 μm for Maestro; reproducibility limit was ≤9.2 μm for Triton and ≤14.4 μm for Maestro. In eyes with retinal pathology, the repeatability coefficient of variation (CV)% was ≤2.6% for Triton and ≤3.4% for Maestro; reproducibility CV% was ≤3.3% for Triton and ≤3.5% for Maestro. Both Triton SS-OCT and Maestro SD-OCT provide reliable measurements of retinal thickness in healthy eyes and eyes with retinal diseases. Excellent agreement between the two devices indicates interoperability when testing healthy eyes or eyes with retinal pathology. These findings support the use of thickness measurements from Triton SS-OCT and Maestro SD-OCT in clinical practice.

Optical Coherence Tomography Features of Macular Hyperpigmented Lesions without Intraretinal Hyperreflective Foci in Age-Related Macular Degeneration

Purpose To evaluate the optical coherence tomography (OCT) features of hyperpigmented lesions in the absence of intraretinal hyperreflective foci (IHRF) on OCT in eyes with age-related macular degeneration (AMD). Methods We retrospectively analyzed OCT images of eyes with intermediate AMD (iAMD) and macular hyperpigmentation (HP) on color fundus photograph (CFP) but without IHRF on OCT in the corresponding location. The most prominent or definite HP was selected for analysis. The infrared reflectance (IR) image registered with the CFP, and the location corresponding to the HP lesion were defined on the IR image. The location of the HP on the corresponding OCT B-scan was assessed for retinal pigment epithelium (RPE) elevation, acquired vitelliform lesion (AVL), abnormal retinal pigment epithelium + basal lamina (RPE + BL) band reflectivity, RPE + BL band thickening, as well as interdigitation zone (IZ), ellipsoid zone (EZ) and external limiting membrane (ELM) disruption. Results 49 eyes (39 patients) were included in this study. Forty-six (94%) of the hyperpigmented lesions showed a thickened RPE + BL band. RPE + BL band reflectivity was increased in 37 (76%) of the lesions. RPE + BL band thickening, however, was not correlated with RPE + BL band reflectivity (p-value = 0.31). Either thickening or hyperreflectivity of the RPE + BL band was present in all cases. Twenty (41%) lesions had evidence of ELM disruption, 42 (86%) demonstrated EZ disruption and 48 (98%) had IZ disruption. Five (10%) HPs demonstrated AVL. Among cases with RPE elevation (15 cases, 31%), 10 were classified as drusen, 2 as drusenoid PEDs, and 3 as fibrovascular PEDs. Conclusions Thickening and/or hyperreflectivity of the RPE + BL band commonly correspond to regions of macular hyperpigmentation without IHRF in eyes with iAMD.

Evaluation of Schlemm Canal Parameters Using Swept-Source Optical Coherence Tomography in Eyes That Underwent Keratoplasty.

In this study, we aimed to evaluate Schlemm canal parameters using anterior segment swept-source optical coherence tomography in eyes that underwent keratoplasty and compare them with keratoconus and healthy control groups. The study included 32 patients who underwent penetrating keratoplasty or deep anterior lamellar keratoplasty once due to keratoconus and age-matched and sex-matched 20 keratoconus patients and 30 healthy controls. In all the patients, a single horizontal image centered on the central cornea was obtained from the nasal and temporal quadrants with low-intensity scanning to visualize Schlemm canal. There was no statistically significant difference between the groups for age and gender ( P ˃0.05). In the keratoplasty group, the area and diameter of Schlemm canal were 2.266±1.141μm 2 and 160.77±65.08 μm, respectively, in the nasal quadrant and 2.623±1.277 μm 2 and 158.81±68.05 μm, respectively in the temporal quadrant, which were statistically significantly lower compared with other groups ( P <0.001 for all). There was no significant difference between the penetrating and deep anterior lamellar keratoplasty subgroups for Schlemm canal parameters. This is the first study to report anterior segment optical coherence tomography after surgery shows SC parameters that are, on average, less than age-matched and keratoconus controls.

Drusen morphometrics on optical coherence tomography in eyes with age-related macular degeneration and normal aging.

To compare drusen size metrics (apical height and basal width) on optical coherence tomography (OCT) B-scans with their size assessed on color photos in eyes with age-related macular degeneration (AMD) and normal aging. A total of 508 drusen were evaluated in this analysis. Flash color fundus photos (CFP), infrared reflectance (IR) images, and OCT B-scans obtained at the same visit were evaluated. Individual drusen were identified on CFPs and the diameters of the drusen were measured in planimetric grading software. CFPs were manually registered to the IR image with their corresponding OCT volume. After confirming correspondence between the CFP and OCT, the apical height and basal width of the same drusen were measured on OCT B-scans. Drusen were divided into small, medium, large, and very large categories based on their diameter on the CFP images (< 63, 63 to 124, 125 to 249, and [Formula: see text] 250μm, respectively). The OCT apical height of small drusen on CFP ranged from 20 to 31μm, while medium drusen ranged from 31 to 46μm, large drusen ranged from 45μm to 111µm, and very large drusen ranged from 55μm to 208μm. The OCT basal width measured < 99μm in small drusen, from 99 to 143μm in medium drusen, from 141 to 407µm in large drusen, and > 209µm in very large drusen. Drusen of different size categories on color photographs may also be separated according to their apical height and basal width on OCT. The apical height and basal width ranges defined in this analysis may be of value in the design of an OCT-based grading scale for AMD.

Vascular and structural alterations of the choroid evaluated by optical coherence tomography angiography and enhanced-depth imaging optical coherence tomography in eyes with reticular pseudodrusen and soft drusen

BackgroundTo assess the vascularity of choriocapillaris and structural choroidal differences in eyes with reticular pseudodrusen (RPD) and soft drusen. Methods21 eyes with RPD (group 1), 17 eyes with soft drusen (group 2), and 19 eyes as a control group (group 3) were included in this study. Choriocapillaris vascular density and flow area were measured by optical coherence tomography angiography. Total choroidal area, luminal area, stromal area, and lumen/stroma ratios were measured on optical coherence tomography B-scans converted to binary images. ResultsMean choriocapillaris vascular density was higher in group 3 than other groups (group 1 vs 3, p = 0.001; group 2 vs 3, p = 0.003). Mean flow area in choriocapillaris was higher in group 3 than other groups (group 1 vs 3, p = 0.001; group 2 vs 3, p = 0.001). Mean luminal, stromal, and total choroidal areas decreased in group 1 and group 2 compared to controls (p < 0.001, p < 0.001, and p < 0.001, respectively). The stroma ratio decreased in group 1 compared to group 3 (p = 0.013). The lumen ratio and lumen/stroma ratio increased in group 1 compared to group 3 (p = 0.012 and p = 0.008, respectively). ConclusionsThe choroid of eyes with RPD and soft drusen was affected in both choriocapillaris and whole choroid layer.

Quantitative Analysis of Gap Between the Intraocular Lens and Posterior Capsule Using Microscope-Integrated Optical Coherence Tomography in Eyes Undergoing Phacoemulsification.

PurposeTo quantitatively analyze the dimensions of the gap between the intraocular lens (IOL) and the posterior capsule using microscope-integrated optical coherence tomography (MIOCT).SettingInstitutional.DesignProspective, interventional.MethodsA total of 105 eyes of 105 consecutive patients planned for phacoemulsification with IOL implantation were enrolled. At the end of surgery, the gap between the IOL and the posterior capsule (IOL-PC gap) was measured using MIOCT (RESCAN). The same gap was reassessed at 1 week follow-up visit using the Visante-OCT system. The cases were sub-grouped based on the grade of cataract, IOL material, size and design and were analyzed to look for any difference in the IOL-PC gap both intraoperatively and postoperatively.ResultsThe IOL-PC gap could be successfully measured intra-operatively in all cases, using the RESCAN. The mean gap at the end of phacoemulsification was 385.08±264.58 µm, and at one week follow up this was 120.83± 95.13 µm.ConclusionMIOCT may be successfully used to quantify the dimensions of the gap between the IOL and the posterior capsule. It can be used as a potential tool to further understand the dynamics of the IOL-PC space and to assess the impact of various IOL and non-IOL parameters implicated in the causation of posterior capsule opacification.

Automated segmentation for whole human eye OCT image using RM multistage Mask R-CNN

Accurate segmentation of structures in whole human eye optical coherence tomography (OCT) images can improve the accuracy of disease diagnosis and ophthalmic biological parameter measurement. However, due to the complex features of the cornea, lens, and retina in the whole human eye OCT image and external interference, it is difficult to precisely extract the object features, which restricts the segmentation accuracy of whole human eye OCT images. A relation module (RM) multistage Mask Region-based Convolutional Neural Network (R-CNN) method for whole human eye OCT image segmentation is established. Based on Mask R-CNN, modulated deformable convolution is employed to produce an irregular receptive field and improve the adaptability of the network to the whole human eye OCT image’s object deformation. In the feature map extraction, the RM is combined to learn the position relation feature map of the human eye structures, which is utilized to enhance feature maps. A multistage mask is constructed in the segmentation branch, and the error is corrected through iterations of the mask to improve the segmentation accuracy of the whole human eye OCT image. Combined with the above structures, the RM multistage Mask R-CNN method is constructed for whole human eye OCT image segmentation. The model is trained by whole human eye OCT images and is applied to realize highly accurate whole human eye OCT image segmentation. Comparison experiments with K-means, U-net, and Feature Pyramid Networks (FPN)-deformable-mask R-CNN are performed to verify the segmentation accuracy and robustness of the proposed method to complex deformation and external interference.

Evaluation of Lamina Cribrosa by Using Enhanced Depth Imaging Optical Coherence Tomography in Ocular Sarcoidosis during Quiescent Phase.

Enhanced depth imaging optical coherence tomography is a useful method to allow for the evaluation of deep ocular structures, such as choroid and lamina cribrosa (LC), which are affected by ocular diseases. We hypothesized that choroidal and optic nerve inflammation in patients with ocular sarcoidosis (OS) might affect the LC structure. This study aimed to evaluate changes in the LC and anterior LC depth (ALCD) in patients with OS. Forty-eight eyes of 26 patients with OS who received the treatment of panuveitis and were in the quiescent phase for at least 6 months were included in the study. Thirty healthy subjects' randomly selected eyes were selected as a control group. Eyes with OS were divided into two subgroups according to the presence (OS eyes with glaucoma [OSWG], n = 23) or absence of glaucoma (OS eyes without glaucoma [OSWOG], n = 25). The LC thickness, ALCD, and peripapillary choroidal thickness were measured using enhanced depth imaging optical coherence tomography in eyes with OS and in controls. The mean LC thickness was found significantly thinner in both OSWG and OSWOG eyes compared with the healthy controls (P < .001 and P = .001, respectively). The mean ALCD was found significantly higher in OSWG eyes (462 ± 65 μm) compared with OSWOG eyes (417 ± 58 μm) and the healthy control eyes (397 ± 59 μm; P = .03 and P = .001, respectively). The average peripapillary choroidal thickness was found to be significantly thinner in OSWG eyes compared with the control eyes (P = .05). The present study revealed that OS is associated with a thinned LC independent of the presence of glaucoma. The degenerative changes in the LC, which is the transition point of the retinal nerve fibers, may cause long-term visual dysfunction in OS. These degenerative changes should be prevented by controlling inflammation with early diagnosis and treatment in patients with OS.

Reference variance and adjustment factor based wave atoms image speckle reduction method for optical coherence tomography images

Speckle noise in optical coherence tomography (OCT) images causes blurring of small targets and structural edges in the image, which reduces the quality of OCT images. To address this problem, a reference variance and adjustment factor based wave atoms image speckle reduction method for OCT images is proposed. First, reference image and adjustment factor were introduced, and reference image speckle noise reference variance was adjusted using adjustment factor to obtain the target image speckle noise variance. Then, a wave atoms threshold equation including the reference variance and the adjustment factor was constructed to obtain an accurate wave atoms noise reduction threshold. On this basis, speckle noise was shrunk using the wave atoms noise reduction threshold to achieve speckle noise reduction in OCT images, and OCT images with clear small targets and sharp structure edges were obtained. The effectiveness and advantages of the proposed method were illustrated with human eye OCT image and retinal OCT image.

Ciliary muscle dimensions measured by swept-source optical coherence tomography in eyes with primary open-angle glaucoma and healthy eyes.

To compare in vivo swept-source optical coherence tomography (SS-OCT) measurements of the ciliary muscle (CM) in patients with primary open-angle glaucoma (POAG) and healthy subjects, and examine correlations between CM dimensions and several covariates. This was a cross-sectional study of the right eyes of 181 subjects: 89 POAG patients and 92 healthy subjects. Using the Triton SS-OCT device (Topcon, Tokyo, Japan), CM length (CML), area (CMA) and thickness measured 1000µm (CMT1), 2000µm (CMT2) and 3000µm (CMT3) from the scleral spur were determined in the temporal and nasal quadrants. POAG patients were subjected to visual field (VF) and peripapillary retinal nerve fiber layer (RNFL) assessment. CM dimensions were then assessed for correlation with VF mean defect (MD), mean RNFL thickness and intraocular pressure (IOP). Mean CMLs were 4325 ± 340µm and 4195 ± 843µm for the healthy subjects and POAG patients, respectively (p = 0.17). Mean CM thicknesses were CMT1 = 546 ± 56µm, CMT2 = 326 ± 44µm and CMT3 = 174 ± 16µm in the healthy eyes versus CMT1 = 534 ± 108, CMT2 = 332 ± 99 and CMT3 = 183 ± 74 in the POAG eyes, with no significant differences detected (all p ≥ 0.25). In the temporal quadrant, mean CMA was 1.12 ± 0.29mm2 and 1.15 ± 0.24mm2 for the healthy and POAG subjects, respectively (p = 0.45). No correlations were observed between CM measurements and RNFL thickness (p ≥ 0.15), IOP or VF MD (p ≥ 0.14) in POAG subjects irrespective of glaucoma severity (p ≥ 0.19). While SS-OCT proved useful to measure CM dimensions in vivo, these dimensions did not differ between healthy individuals and POAG subjects. In the patients with POAG, no correlations were detected between CM dimensions and VF, RNFL or IOP.

Correlation between blood flow on optic nerve head and structural and functional changes in eyes with glaucoma

The purpose of this study was to determine the significance of the correlations between blood flow on the optic nerve head (ONH) using the mean blur rate (MBR) determined by laser speckle flowgraphy and the visual field loss determined by perimetry and the structural alterations by optical coherence tomography in eyes solely with open-angle glaucoma. There were significant differences in the circumpapillary retinal nerve fiber layer thickness (cpRNFLT), and the MBR-tissue, at the different stages of glaucoma (ANOVA, P < 0.001). Univariate linear regression analyses indicated that the mean deviations (MD) were significantly correlated with both the MBR-tissue (r = 0.661, P < 0.001) and the cpRNFLT (r = 0.279, P = 0.005). Logistic regression analyses showed that the MD was significantly correlated with the MBR-tissue (P < 0.001) and the cpRNFLT (P < 0.001). The MBR-tissue was found to be the factor that can best predict the MD based on the Akaike information criteria (P < 0.001). Stepwise multiple logistic regression analyses showed that the MBR-tissue and the cpRNFLT were both risk factors that were significantly associated with the MD (Odds ratio;1.25 and 1.07, P < 0.001 and P < 0.001, respectively). These results indicate that the MBR-tissue was as important as the structural values in diagnosing and determining the prognosis of glaucoma.

Systemic and Ocular Determinants of Choroidal Structures on Optical Coherence Tomography of Eyes with Diabetes and Diabetic Retinopathy

Knowledgeof the choroidal structures in eyes with diabetes and diabetic retinopathy (DR) should provide information on the pathogenesis of DR. A prospective study was performed to determine the systemic and ocular factors that affect the choroidal structures in eyes with diabetes. Two-hundred consecutive diabetic subjects consisted of 160 treatment-naïve patients with different stages of DR and 40 patients with proliferative DR with prior panretinal photocoagulation (PRP). All underwent blood and urine tests and enhanced depth imaging optical coherence tomography (EDI-OCT). The cross-sectional EDI-OCT images of the subfoveal choroid were binarized to measure the total choroidal area (TCA), luminal area, and stromal area. Multivariate regression analyses were performed to determine the systemic and ocular factors that were significantly correlated with the choroidal structures. The subfoveal choroidal thickness, TCA, luminal area, and stromal area were larger at more advanced stage of DR, and smaller in eyes with PRP than those without (P < 0.001). The TCA and stromal area were significantly and positively correlated with the degree of albuminuria (P = 0.034, P = 0.025, respectively). The choroidal lumen and stroma may increase as the stages of DR progress and decrease after PRP. Albuminuria may be associated with the choroidal stromal edema.

Utility of Optical Coherence Tomography (OCT) in Centers For Medicare and Medicaid Services (CMS)-defined Severe Glaucoma Patients.

Patients with Centers For Medicare and Medicaid Services (CMS)-defined severe glaucoma often have clinically useful remaining retinal nerve fiber layer (RNFL), suggesting that structurally based rather than functionally based criteria would be more appropriate to use as guidelines for the utilization of optical coherence tomography (OCT) imaging. RNFL OCT in glaucomatous eyes with advanced structural damage can reach a floor after which there is no further detectable thinning of RNFL. Insurers are considering limiting coverage for OCT in "severe stage glaucoma" defined by CMS. However, CMS definitions of severe glaucoma are based primarily on visual field criteria. Many of these patients may have preserved RNFL in other sectors. This study aims to assess the clinical utility of RNFL measurements by OCT in eyes with CMS-defined severe glaucoma. Medical records of patients with CMS-defined severe glaucoma were consecutively reviewed. Data collected included average/sectoral RNFL thickness, and visual field mean deviation. Previous estimates of RNFL floor and test-retest variability for Cirrus OCT were used to establish 3 threshold values of RNFL. Data analysis included descriptive statistics, χ analysis, and analysis of variance. A total of 129 eyes qualified (age: 71±12 y; mean deviation: -13.5±4.3 dB; average RNFL: 60.9±7.9 μm), A majority (66%) of eyes met severe glaucoma criteria with defects in both hemifields; 34% met only paracentral defect criteria. The proportion of eyes that had significant remaining average, superior, or inferior RNFL, estimated by thresholds 1 to 3, was 21% to 54%, 29% to 51%, and 16% to 37%, respectively. At least 1 vertical quadrant had significant remaining RNFL in 35% to 66% of eyes, depending on the threshold used. Our data demonstrate a substantial portion of eyes with CMS-defined severe glaucoma have measurable RNFL above the floor in at least 1 vertical quadrant that may be longitudinally monitored for progression. The presence of CMS-defined severe glaucoma does not exclude the potential utility of OCT to monitor progression.

FOCAL DISRUPTIONS IN ELLIPSOID ZONE AND INTERDIGITATION ZONE ON SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN PACHYCHOROID PIGMENT EPITHELIOPATHY.

To describe a distinctive focal disruption of the ellipsoid zone (EZ)/interdigitation zone (IZ) determined by spectral-domain optical coherence tomography in eyes with pachychoroid pigment epitheliopathy. Twenty patients with focal EZ/IZ disruptions associated with pachychoroid without history or findings indicative of subretinal fluid were evaluated. Detailed clinical/imaging characteristics and their longitudinal changes were evaluated. A total of 27 lesions from 21 eyes were included. The mean subfoveal choroidal thickness was 450 μm. In six of seven eyes with previous imaging data to compare, characteristic drusenoid lesions associated with thick choroid preceded focal EZ/IZ disruptions at the corresponding sites. Dilated outer choroidal vessels were noted beneath the focal EZ/IZ disruption in 24 lesions (88.9%), with attenuation of choriocapillaris in 18 lesions (66.7%). The external limiting membrane was intact in all lesions. All except three eyes did not show morphologic changes, and mean visual acuity was maintained (Snellen equivalent, 20/25) during a mean follow-up period of 20 months. Focal disruptions of the EZ/IZ band can develop in pachychoroid eyes in the absence of subretinal fluid, with a stable clinical course, and possibly as a result of regression of drusenoid lesions. This may represent an atrophic form of pachychoroid manifestation.

Intraretinal layer segmentation and parameter measurement in optic nerve head region through energy function of spatial-gradient continuity constraint

For the diagnosis of glaucoma, optical coherence tomography (OCT) is a noninvasive imaging technique for the assessment of retinal layers. To accurately segment intraretinal layers in an optic nerve head (ONH) region, we proposed an automatic method for the segmentation of three intraretinal layers in eye OCT scans centered on ONH. The internal limiting membrane, inner segment and outer segment, Bruch’s membrane surfaces under vascular shadows, and interaction of multiple high-reflectivity regions in the OCT image can be accurately segmented through this method. Then, we constructed a novel spatial-gradient continuity constraint, termed spatial-gradient continuity constraint, for the correction of discontinuity between adjacent image segmentation results. In our experiment, we randomly selected 20 B-scans, each annotated three retinal layers by experts. Signed distance errors of −0.80 μm obtained through this method are lower than those obtained through the state-of-art method (−1.43 μm). Meanwhile, the segmentation results can be used as bases for the diagnosis of glaucoma.