Shiho Kunimatsu-Sanuki

Fiber-based polarization-sensitive OCT for birefringence imaging of the anterior eye segment

We demonstrate a prototype system of polarization-sensitive optical coherence tomography (PS-OCT) designed for clinical studies of the anterior eye segment imaging. The system can measure Jones matrices of the sample with depth-multiplexing of two orthogonal incident polarizations and polarization-sensitive detection. An optical clock is generated using a quadrature modulator and a logical circuit to double the clock frequency. Systematic artifacts in measured Jones matrices are theoretically analyzed and numerically compensated using signals at the surface of the sample. Local retardation images of filtering blebs after trabeculectomy show improved visualization of subconjunctival tissue, sclera, and scar tissue of the bleb wall in the anterior eye segment.

An assessment of driving fitness in patients with visual impairment to understand the elevated risk of motor vehicle accidents

Objective To assess the driving fitness of patients with glaucoma by identifying specific areas and degrees of visual field impairment that threaten safe driving. Design Case–control study. Setting, and participants This prospective study included 36 patients with advanced glaucoma, defined as Humphrey field analyzer (HFA; 24-2 SITA standard program) measurements of mean deviation in both eyes of worse than −12 dB, and 36 age-matched and driving exposure time-matched normal subjects. All participants underwent testing in a novel driving simulator (DS) system. Participants were recruited between September 2010 and January 2012. Main outcome measures The number of collisions with simulated hazards and braking response time in 14 DS scenarios was recorded. Monocular HFA 24-2 test results from both eyes were merged to calculate the binocular integrated visual field (IVF). The position of the IVF subfields in which the collision-involved patients had lower sensitivity than the collision-uninvolved patients was compared with the track of the hazard. The cut-off value to predict an elevated risk of collisions was determined, as were its sensitivity and specificity, with the area under the receiver operating characteristic (AUROC) curve. Results Patients with advanced glaucoma were involved in a significantly higher number of collisions in the DS than the age-matched and driving exposure time-matched normal subjects (119 vs 40, respectively, p<0.0001), especially in four specific DS scenarios. In these four scenarios, IVF sensitivity was significantly lower in the collision-involved patients than in the collision-uninvolved patients in subfields on or near the track of the simulated hazard (p<0.05). The subfields with the largest AUROC curve had values ranging from 0.72 to 0.91 and were located in the paracentral visual field just below the horizontal. Conclusions Our novel DS system effectively assessed visual impairment, showing that simulators may have future potential in educating patients.

Characteristic Profiles of Inflammatory Cytokines in the Aqueous Humor of Glaucomatous Eyes

ABSTRACT Purpose: To analyze cytokine profiles of the aqueous humor of eyes with primary open-angle glaucoma (POAG), neovascular glaucoma (NVG), and cataract (as controls). Methods: A multiplex bead assay was used to measure concentrations of 27 cytokines in aqueous humor samples from 54 eyes. Results: Detection rates were as follows: IL-7: NVG higher than POAG; IL-10: POAG lower than cataract or NVG; and GM-CSF: cataract higher than POAG or NVG. Concentrations were as follows: IL-8, IP-10, MCP-1, and MIP-1β: POAG and NVG higher than cataract; IL-9: POAG lower than NVG; IL-12: POAG lower than cataract or NVG; and VEGF: NVG higher than cataract or POAG and POAG lower than cataract. Further analysis showed that IL-8, IP-10, MCP-1, and MIP-1β were correlated with intraocular pressure and age. Conclusions: The detection rates and levels of various cytokines had different patterns in POAG and NVG patients, suggesting distinctive alterations in the microenvironment in different types of glaucoma.

Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography

Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarization-sensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample. In addition, we introduce entropy that shows the randomness of the polarization property. Underestimation of the entropy at a low sampling number is mitigated by asymptotic quasi maximum likelihood estimator. A bias of the entropy from random noises is corrected to show only the polarization property inherent in the sample. The theory is validated with experimental measurements of a glass plate and waveplates, and applied to the imaging of a healthy human eye anterior segment as an image filter.

The role of specific visual subfields in collisions with oncoming cars during simulated driving in patients with advanced glaucoma

Background/aims To assess the role of specific visual subfields in collisions with oncoming cars during simulated driving in patients with advanced glaucoma. Methods Normal subjects and patients with glaucoma with mean deviation <–12 dB in both eyes (Humphrey Field Analyzer 24-2 SITA-S program) used a driving simulator (DS; Honda Motor, Tokyo). Two scenarios in which oncoming cars turned right crossing the drivers path were chosen. We compared the binocular integrated visual field (IVF) in the patients who were involved in collisions and those who were not. We performed a multivariate logistic regression analysis; the dependent parameter was collision involvement, and the independent parameters were age, visual acuity and mean sensitivity of the IVF subfields. Results The study included 43 normal subjects and 100 patients with advanced glaucoma. And, 5 of the 100 patients with advanced glaucoma experienced simulator sickness during the main test and were thus excluded. In total, 95 patients with advanced glaucoma and 43 normal subjects completed the main test of DS. Advanced glaucoma patients had significantly more collisions than normal patients in one or both DS scenarios (p<0.001). The patients with advanced glaucoma who were involved in collisions were older (p=0.050) and had worse visual acuity in the better eye (p<0.001) and had lower mean IVF sensitivity in the inferior hemifield, both 0°–12° and 13°–24° in comparison with who were not involved in collisions (p=0.012 and p=0.034). A logistic regression analysis revealed that collision involvement was significantly associated with decreased inferior IVF mean sensitivity from 13° to 24° (p=0.041), in addition to older age and lower visual acuity (p=0.018 and p<0.001). Conclusions Our data suggest that the inferior hemifield was associated with the incidence of motor vehicle collisions with oncoming cars in patients with advanced glaucoma.

Structure/function relationship between wide‐scan binocular OCT images and the integrated visual field in glaucoma patients

Catherine J Choi MD MS, Anna M Stagner MD, Suzanne K Freitag MD, Frederick A Jakobiec MD DSC, and Nahyoung Grace Lee MD, Ophthalmic Plastic Surgery, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, David G. Cogan Ophthalmic Pathology Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts USA Received 12 December 2015; accepted 20 December 2015.

Comparing trabeculectomy outcomes between first and second operated eyes: A multicenter study

Objective To compare surgical outcomes between the first and second operated eyes in patients who underwent trabeculectomy in both eyes. Methods This retrospective clinical cohort study at five clinical centers in Japan included 84 patients with open-angle glaucoma who underwent primary trabeculectomy in both eyes. The primary outcome was surgical success or failure, with failure being defined according to three criteria: <20% reduction of the preoperative intraocular pressure (IOP), or Criterion A, IOP >21 mmHg; Criterion B, IOP >18 mmHg; or Criterion C, IOP >15 mmHg. Cases of reoperation, a loss of light perception vision, or hypotony were also considered as “failures”. Results There were no significant differences in success rate for any of the three criteria between the first and second operated eyes. For patients whose first trabeculectomy was successful, when the second trabeculectomy was performed ≥2 months after the first, the survival curves for all three criteria for the second trabeculectomy were significantly worse than those for patients waiting a shorter interval between trabeculectomies (Criterion A, 52.0% vs 83.6%, P = 0.0031; Criterion B, 51.5% vs 80.4%, P = 0.026; Criterion C, 51.1% vs 80.4%, P = 0.048). In multivariable analyses, a longer interval between trabeculectomies was a significant prognostic factor for surgical failure (Criterion A, P = 0.0055; Criterion B, P = 0.0023; Criterion C, P = 0.027). However, no dependency on the interval between trabeculectomies was found among patients whose first trabeculectomy failed. Conclusions If the first trabeculectomy is successful, a long interval before the second trabeculectomy increases the risk of surgical failure in the second eye. This result has clinical implications for developing surgical strategies for patients with bilateral glaucoma.

The effect of concentric constriction of the visual field to 10 and 15 degrees on simulated motor vehicle accidents

Purpose Traffic accidents are associated with the visual function of drivers, as well as many other factors. Driving simulator systems have the advantage of controlling for traffic- and automobile-related conditions, and using pinhole glasses can control the degree of concentric concentration of the visual field. We evaluated the effect of concentric constriction of the visual field on automobile driving, using driving simulator tests. Methods Subjects meeting criteria for normal eyesight were included in the study. Pinhole glasses with variable aperture sizes were adjusted to mimic the conditions of concentric visual field constrictions of 10° and 15°, using a CLOCK CHART®. The test contained 8 scenarios (2 oncoming right-turning cars and 6 jump-out events from the side). Results Eighty-eight subjects were included in the study; 37 (mean age = 52.9±15.8 years) subjects were assigned to the 15° group, and 51 (mean = 48.6±15.5 years) were assigned to the 10° group. For all 8 scenarios, the number of accidents was significantly higher among pinhole wearing subjects. The average number of all types of accidents per person was significantly higher in the pinhole 10° group (4.59±1.81) than the pinhole 15° group (3.68±1.49) (P = 0.032). The number of accidents associated with jump-out scenarios, in which a vehicle approaches from the side on a straight road with a good view, was significantly higher in the pinhole 10° group than in the pinhole 15° group. Conclusions Concentric constriction of the visual field was associated with increased number of traffic accidents. The simulation findings indicated that a visual field of 10° to 15° may be important for avoiding collisions in places where there is a straight road with a good view.

Anterior-Segment Optical Coherence Tomography for Predicting Postoperative Outcomes After Trabeculectomy

ABSTRACT Purpose: To determine whether anterior-segment optical coherence tomography (AS-OCT) can be used to predict post-trabeculectomy bleb outcomes. Materials and methods: We divided 58 eyes of 47 trabeculectomy patients into success or failure groups based on their status at 12 months after surgery. We then compared various AS-OCT measurement parameters between the two groups at 1 and 2 weeks and 1, 3, 6, and 12 months. We also analyzed the early post-trabeculectomy bleb parameters with multiple logistic regression, stepwise multiple regression, and the receiver operating characteristic (ROC) curve, to evaluate the power of these parameters to predict long-term outcomes. Results: Intraocular pressure 3 or more months after trabeculectomy was significantly lower in the success group than the failure group (all: P < 0.0016). Cleft volume was significantly higher 6 or more months after trabeculectomy in the success group than the failure group (P = 0.0027 and <0.0016). Reflectivity of the bleb wall was significantly higher in the failure group than the success group at 2 weeks and all later time points (all: P < 0.0016). Reflectivity of the bleb wall at 2 weeks after trabeculectomy was a risk factor for failure, with an odds ratio (OR) for failure of 2.48 (95% confidence interval, 1.31–4.68, increasing per 10 AU). The area under the ROC curve for reflectivity of the bleb wall at 2 weeks after trabeculectomy was 0.775 when the cutoff value was set at 122.8, with sensitivity, specificity, and OR of 78.3%, 80.0%, and 14.4, respectively. A stepwise multiple regression analysis showed that reflectivity of the bleb wall at 2 weeks was an independent factor indicating postoperative bleb survival period (β = −0.39, P = 0.007). Conclusions: Reflectivity of the bleb wall, measured by AS-OCT, may be an early post-trabeculectomy predictor of bleb outcome.

Predicting the Integrated Visual Field with Wide-Scan Optical Coherence Tomography in Glaucoma Patients

ABSTRACT Purpose: This study aimed to calculate a predicted integrated visual field (IVF) based on predicted monocular visual fields (MVFs) derived, with a new method, from wide-scan optical coherence tomography (OCT) data. Materials and Methods: Visual field testing used the central (6 × 4) 24 points of the Humphrey Field Analyzer 24-2 program. OCT scans of a corresponding retinal area, centered on the fovea, were divided into a 6 × 4 grid. The thickness of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer + inner plexiform layer (GCIPL), and mRNFL + GCIPL (GCC) was measured in each grid area. Next, a support vector machine was used to create a MVF prediction model, with training data from 101 eyes of 60 glaucoma patients. Then, the prediction model was validated with data from 108 eyes of 54 glaucoma patients, for MVF and IVF. A simulated IVF was created by merging bilateral simulated MVFs. Results: The overall average of the median 95% prediction interval length for the MVF prediction model (measured in dB) was 10.0, 18.3, and 11.3 for the mRNFL, GCIPL, and GCC, respectively. In the validation data, the overall average root mean squared error (dB) between actual and predicted sensitivity for the IVF was 9.6, 10.5, and 9.5 for the mRNFL, GCIPL, and GCC, respectively, in the 24 grid areas. The intraclass correlation coefficient between average actual and predicted IVF was 0.61, 0.44, and 0.59 in the mRNFL, GCIPL, and GCC, respectively, in the 24 grid areas. Conclusions: We calculated a predicted IVF based on predicted MVFs that were derived, with a new method, from OCT data and validated the accuracy of the calculated IVF. This technique should improve glaucoma management in cases when standard visual field testing is difficult.