Baseline characteristics associated with the incidence of intraocular inflammation after the intravitreous injection of brolucizumab.

PURPOSE: To investigate baseline characteristics associated with the incidence of intraocular inflammation (IOI) after the intravitreal injection of brolucizumab (IVBr) for the treatment of neovascular age-related macular degeneration (nAMD). METHODS: This retrospective study included 66 eyes of 62 consecutive patients with nAMD who received IVBr (18 eyes were treatment naïve and 48 eyes had switched from other anti-vascular endothelial growth factor [VEGF] therapy). Baseline clinical characteristics were compared in non-IOI and IOI groups. RESULTS: Although a dry macula was achieved at a high rate even 6 months after IVBr, IOI occurred in 8 of 66 eyes (12.1%; all had switched therapy) during the study period. Baseline characteristics including age, sex, nAMD type, lens status, visual acuity, central macular thickness, and a history of diabetes did not differ between the groups. The number of previous anti-VEGF injections before IVBr was greater in the IOI group (P = 0.004), and the ratio of patients with a laser flare-cell photometry (LFCP) value over 15 photon count per millisecond (pc/ms) was higher in the IOI group (P = 0.017). Multivariate logistic regression analysis showed that a greater number of previous anti-VEGF injections (odds ratio [OR]: 1.12, P = 0.006; area under the curve: 0.82, cut-off score: 14.0) and an LFCP value over 15 pc/ms (OR: 81.6, P = 0.031) were significantly associated with the incidence of IOI after IVBr. CONCLUSION: A number of previous anti-VEGF injections greater than 14 and an LFCP value more than 15 pc/ms might be useful predictors of the incidence of IOI after IVBr in eyes with nAMD.

RETINAL SENSITIVITY AND VESSEL DENSITY AFTER MACULAR HOLE SURGERY WITH THE SUPERIOR INVERTED INTERNAL LIMITING MEMBRANE FLAP TECHNIQUE.

PURPOSE: To evaluate retinal vessel density and retinal sensitivity (RS) after macular hole surgery with the superior inverted internal limiting membrane flap technique. METHODS: Retrospective, observational case series. Twenty-one patients with idiopathic macular hole underwent 27-gauge vitrectomy with the superior inverted internal limiting membrane flap technique and triamcinolone acetonide. Measurements included RS, which was measured with microperimetry, as well as retinal vessel density in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), which was measured with optical coherence tomography angiography. All parameters were evaluated in the superior and inferior sectors of the macula preoperatively and 1, 3, and 6 months postoperatively. RESULTS: Six months postoperatively, retinal thickness in the inferior sector was unchanged, but retinal thickness in the superior sector decreased significantly (P < 0.01). SCP vessel density in both sectors was unchanged at all postoperative time points. DCP vessel density in both sectors increased very significantly at 3 months (P < 0.01) and returned to baseline at 6 months. RS in the inferior sector increased by 47% 3 months postoperatively and by 61% 6 months postoperatively (P < 0.05 and P < 0.001, respectively), but RS in the superior sector increased only at 6 months postoperatively and only by 22% (P < 0.05). CONCLUSION: Lower recovery of RS in the superior sector suggests that internal limiting membrane peeling might affect the postoperative visual function.

Successful surgical outcomes after 23-, 25- and 27-gauge vitrectomy without scleral encircling for giant retinal tear.

PURPOSE: Retinal detachment due to giant retinal tears (GRTs), tears larger than 90°, is rare and difficult to treat. Here, we show and compare surgical results of 23-, 25- and 27-gauge (G) micro-incision vitrectomy surgery (MIVS) for GRT. STUDY DESIGN: Retrospective and interventional case series. METHODS: Retrospective review of 41 eyes of 38 patients with GRT who underwent MIVS. Surgical outcomes after MIVS, including reattachment rates and postoperative complications, were compared between instrument gauges. All patients were followed for at least 6 months postoperatively. RESULTS: MIVS with 23G, 25G and 27G instruments was performed in 7, 19 and 15 eyes, respectively. Silicone oil (SO) was used in 34 of 41 eyes (83%) with a mean removal time of 43.8 days after first surgery. Best-corrected visual acuity (BCVA) was recovered or maintained in 39 eyes (95%). Reattachment was attained after initial surgery in 38 of 41 eyes (93%) (23G: 6/7 [86%]; 25G: 17/19 [89%]; 27G: 15/15 [100%]). Final reattachment was eventually achieved in all eyes (two eyes needed support from scleral encircling). Postoperative complications occurred in 16 eyes (39%) (23G: 3/7 [43%]; 25G: 8/19 [42%]; 27G: 5/15 [33%]), including macular pucker, cystoid macular edema, macular hole, subretinal perfluorocarbon liquid, retinal folds, vitreous hemorrhage and redetachment. There were no significant differences between the three groups in rate of high myopia, GRT size, operation time, phacovitrectomy rate, SO usage rate, initial reattachment rate, final reattachment rate, preoperative BCVA, final BCVA or rate of postoperative complications. CONCLUSION: Despite occasional postoperative complications, primary MIVS, regardless of gauge size, appears to be a safe and feasible option for GRT surgery.

The optic nerve head vasoreactive response to systemic hyperoxia and visual field defect progression in open-angle glaucoma, a pilot study.

PURPOSE: To investigate the effect of optic nerve head (ONH) tissue vasoreactivity on glaucoma visual field defect progression. METHODS: This prospective, longitudinal study comprised 28 eyes of 16 patients with open-angle glaucoma. Baseline data were obtained from oxygen inhalation testing, including laser speckle flowgraphy measurements of tissue-area mean blur rate (MT), which represents ONH tissue blood flow, and the mean percentage change in MT (MT-change). Follow-up data were collected for at least 2 years, including at least 5 reliable visual field tests. The average total deviation (TD) was calculated in each sector of the Garway-Heath map; in this study, superior, central and inferior TD corresponded to inferior, temporal and superior MT or MT-change, respectively. MT and MT-change in three sectors per eye were included as explanatory variables in a multivariable linear mixed-effects model, with TD slope set as the response variable. RESULTS: At baseline, lower MT and higher diastolic blood pressure were associated with lower MT-change (p < 0.05). Additionally, MT-change significantly contributed to TD slope in the corresponding sectors (ß = 0.41, p = 0.01). CONCLUSIONS: Weaker ONH tissue vasoreactivity to systemic hyperoxia, assessed with laser speckle flowgraphy, was associated with lower baseline ONH tissue blood flow, higher diastolic blood pressure and rapid visual field defect progression. Laser speckle flowgraphy variables during oxygen provocation testing may represent potentially useful predictive biomarkers of glaucoma progression.

Quantitative analysis of the macula with optical coherence tomography angiography in normal Japanese subjects: The Taiwa Study.

This study evaluated age-related changes in the superficial and deep retinal capillary plexus (SCP and DCP, respectively) and in the foveal avascular zone (FAZ). SCP and DCP perfusion density (PD) were measured in optical coherence tomography angiography (OCTA) macular scans of 145 eyes of 145 healthy Japanese subjects, and findings were compared with SCP FAZ and clinical data. We found that age was negatively correlated with SCP and DCP PD (r = -0.17, P = 0.04 and r = -0.20, P = 0.02, respectively) and positively correlated with FAZ area (r = 0.18, P = 0.03). SCP and DCP PD were correlated with each other (r = 0.67, P < 0.001). FAZ area was negatively correlated with SCP PD, DCP PD and central macular thickness (CMT) (r = -0.18, P = 0.03; r = -0.25, P < 0.01; and r = -0.39, P < 0.001, respectively). FAZ was larger and CMT was lower (P = 0.01 and P < 0.001, respectively) in women than men. SCP and DCP PD were positively correlated with estimated glomerular filtration rate (r = 0.17, P = 0.03 and r = 0.24, P < 0.01, respectively). Multiple regression analysis confirmed that age independently affected DCP PD and FAZ (P = 0.02 and P < 0.01, respectively) and that CMT independently affected FAZ area (P < 0.001). Thus, normal subjects showed age-related decreases in macular PD and renal function. FAZ and CMT were related, suggesting that age-related changes in macular thickness also affect capillary vasculature.

Sectoral Differences in the Association of Optic Nerve Head Blood Flow and Glaucomatous Visual Field Defect Severity and Progression.

Purpose: To investigate sectoral differences in the relationship between optic nerve head tissue blood flow, anatomically corresponding visual field defect severity, and future progression. Methods: This retrospective longitudinal medical chart review comprised 508 eyes of 319 open-angle glaucoma patients (mean deviation: -9.2 ± 7.0 dB), followed for an average of 4.7 ± 1.1 years; an average 11.7 ± 3.7 visual field tests were performed. Average total deviation (TD) was calculated in the superior, central, and inferior sectors of the Humphrey 24-2 program. The optic nerve head was divided to obtain inferior, temporal, and superior tissue-area mean blur rate (MT), derived from laser speckle flowgraphy. At baseline, the correlation between MT and TD was compared in anatomically corresponding sectors. We performed a multivariate analysis to determine the contribution of baseline MT to corresponding TD slope and to determine background factors influencing superior to temporal MT. We used a linear-mixed effect model for the statistical analysis. Results: At baseline, the highest ß coefficients were found between MT-superior and TD-inferior, MT-temporal and TD-central, and between MT-inferior and TD-superior, in that order (ß = 0.38, ß = 0.27, ß = 0.26, respectively). MT-superior and MT-temporal independently contributed to corresponding TD slope (P < 0.05). Male sex, high body mass index, and the prevalence of sleep apnea syndrome were contributing factors to lower superior to temporal MT (P < 0.05). Conclusions: Review of medical history, measurements of systemic variables, and laser speckle flowgraphy parameters might help clinicians to predict visual field defect severity and progression.

Color visual acuity in preperimetric glaucoma and open-angle glaucoma.

PURPOSE: To investigate the clinical significance of color visual acuity (CVA) in preperimetric glaucoma (PPG) and open-angle glaucoma (OAG). METHODS: A total of 123 eyes of 73 subjects (22 normal eyes, 14 PPG eyes, and 87 OAG eyes; mean age: 44.9 ± 10.1 years, age range: 21-64 years) were enrolled. CVA was tested for red, green-yellow, blue-green and blue-purple with a newly developed test. RESULTS: There was no statistical difference in clinical background factors, including age, sex, intraocular pressure, or spherical equivalent between the three groups. Red VA and blue-green VA were significantly worse in the OAG eyes than in the normal eyes (P = 0.008 and P = 0.015, respectively), although green-yellow VA and blue-purple VA were not significantly worse. Furthermore, red VA and blue-green VA were significantly correlated with MD in a group of eyes with either PPG or OAG (r = -0.23, P = 0.023; r = -0.25, P = 0.012, respectively), but green-yellow VA and blue-purple VA were not. CONCLUSION: Red VA and blue-green VA were detectably worse in eyes with OAG, in close association with the degree of functional loss. This suggests that measuring CVA with the new color test described here may be a promising supplement to existing methods of detecting glaucoma and evaluating its severity.

Surgical results of internal limiting membrane flap inversion and internal limiting membrane peeling for macular hole.

PURPOSE: The internal limiting membrane (ILM) is a normal part of the retina, and the outcomes of ILM removal have not been fully investigated. ILM flap inversion is a recently developed technique that increases the success rate of macular hole (MH) surgery. Thus, we compared the anatomical closure rate and visual outcome in patients undergoing microincision vitrectomy surgery (MIVS) with ILM flap inversion or conventional ILM peeling for the treatment of MH. METHODS: The medical records of 90 eyes with MH were reviewed retrospectively. The patients were classified into two groups based on MIVS procedure (group 1: ILM flap inversion, 46 eyes; group 2: ILM peeling, 44 eyes). RESULTS: Preoperative characteristics were similar in the two groups, and there were no significant differences in 1 month- or 6 month-postoperative VA between the groups (P = 0.25 and P = 0.42, respectively). However, the surgical success rate was significantly higher in group 1 than group 2 (P = 0.04; 46/46: 100% and 41/44: 93%, respectively). Multiple regression analysis revealed that axial length and MH diameter were independent factors predicting 6-month postoperative BCVA in group 2 (P = 0.001 and P = 0.03, respectively), and that MH diameter was an independent factor predicting 6-month postoperative VA in group 1 (P = 0.03). Logistic regression analysis revealed that axial length (OR = 2.11; P = 0.02; area under the curve: 0.94; cut off score: 28.4 mm) was an independent factor indicating surgical failure in group 2. CONCLUSION: Our results suggest that MIVS with ILM flap inversion might be best suited to treat MH, particularly in patients with high myopia.

The Impact of Intraocular Pressure Elevation on Optic Nerve Head and Choroidal Blood Flow.

Purpose: To use laser speckle flowgraphy (LSFG) to assess blood flow (BF) in the optic nerve head (ONH) tissue and choroid during elevated intraocular pressure (IOP). Methods: This prospective study included 20 eyes of 20 healthy volunteers. The testing protocol had a baseline phase, two elevated IOP phases (+10 and +20 mm Hg), and a recovery phase. IOP was elevated by pushing against the eyelid with a novel tubular device attached to the LSFG apparatus. Measurement parameters in each phase included: LSFG-derived mean blur rate (MBR) and flow acceleration index (FAI); systemic parameters, and IOP. The % change against baseline was calculated for each phase. The protocol was repeated five times to calculate the coefficient of variation (CV) for % change MBR and to determine the effect of mydriasis on % change MBR. We compared % change MBR and FAI and evaluated the relationship between % change ocular perfusion pressure (OPP) and MBR in the choroid and ONH tissue. Results: The % change MBR was highly reproducible (CV: 6.1-8.7%) and not affected by mydriasis (P = 0.57-0.96). The % change MBR and FAI were higher in the ONH tissue than choroid during IOP elevation (P = 0.04). The % change OPP and MBR showed positive linear correlations and two-segmental linear correlations in the choroid and ONH tissue, respectively (P < 0.01). Conclusion: Hemodynamics during IOP elevation differ in the choroid and ONH tissue. LSFG enables highly reproducible assessment of the dynamic autoregulation of ocular BF in the ONH tissue.

The Relationship between Peripheral Nerve Conduction Velocity and Ophthalmological Findings in Type 2 Diabetes Patients with Early Diabetic Retinopathy.

PURPOSE: Nerve conduction velocity (NCV) is an indicator of neuronal damage in the distal segment of the peripheral nerves. Here, we determined the association between NCV and other systemic and ocular clinical findings, in type 2 diabetes patients with early diabetic retinopathy (DR). METHODS: This study included 42 eyes of 42 type 2 diabetes patients (median age: 54 years) with no DR or with mild nonproliferative DR. Standard statistical techniques were used to determine associations between clinical findings. RESULTS: Sural sensory conduction velocity (SCV) and tibial motor conduction velocity (MCV) were significantly lower in mild nonproliferative DR patients than patients with no DR (P = 0.008 and P = 0.01, resp.). Furthermore, logistic regression analyses revealed that sural SCV and tibial MCV were independent factors contributing to the presence of mild nonproliferative DR (OR 0.83, P = 0.012 and OR 0.69 P = 0.02, resp.). Tibial MCV was correlated with choroidal thickness (CT) (P = 0.01), and a multiple regression analysis revealed that age, tibial MCV, and carotid intima-media thickness were independent associating factors with CT (P = 0.035, P = 0.015, and P = 0.008, resp.). CONCLUSIONS: Our findings suggest that reduced NCV may be closely associated with early DR in type 2 diabetes patients. Thus, reduced nerve conduction is a potential early biomarker of DR.

Levels of Anti-Retinal Antibodies in Retinal Detachment and Proliferative Vitreoretinopathy.

PURPOSE: The purpose of the study is to investigate the correlation between intraocular anti-retinal antibodies and clinical measurements in patients with rhegmatogenous retinal detachment (RRD) and proliferative vitreoretinopathy (PVR). MATERIAL AND METHODS: Aqueous humor and vitreous samples were collected from patients with RRD, PVR, and from control subjects with macular hole. The levels of total protein (TP), IgG, and anti-retinal antibodies were determined with a bicinchoninic acid assay, enzyme-linked immunosorbent assay, and dot blot, respectively. Correlations between these measurements were assessed using Pearson's correlation test. Analysis of variance followed by a post-hoc test or the Student t-test was used to compare differences between groups. RESULTS: The levels of anti-retinal antibodies and IgG were correlated with each other (P < 0.010). The IgG concentration was higher in patients with PVR than in controls in both the aqueous humor (P < 0.001) and the vitreous (P < 0.001), but not in patients with RRD. Conversely, TP levels and anti-retinal antibodies in both ocular fluids from RRD and PVR patients did not significantly differ from the controls. In a subgroup analysis, vitreal anti-retinal antibody levels were correlated with average macular thickness in the re-attached macula following surgery for macula-off RRD/PVR (P = 0.012). Furthermore, patients with post-operative cystoid macular edema had a higher level of vitreal anti-retinal antibodies than those without (P = 0.009). CONCLUSIONS: Intravitreal anti-retinal antibodies were increased in the eyes with maculopathy after surgical intervention for RRD/PVR.

Preperimetric Glaucoma Prospective Study (PPGPS): Predicting Visual Field Progression With Basal Optic Nerve Head Blood Flow in Normotensive PPG Eyes.

PURPOSE: To investigate the site specificity of visual field changes in eyes with normotensive preperimetric glaucoma (PPG), and to determine factors influencing visual field progression. METHODS: This prospective study comprised 84 eyes of 84 normotensive PPG patients followed for at least 16 months. Optic nerve head (ONH) blood flow was assessed with tissue-area mean blur rate (MBRT), derived from laser speckle flowgraphy. Total deviation (TD) was measured in each sector of the Garway-Heath map to evaluate the site specificity of visual field loss. Subjects with a TD slope in the first quartile were classified as progressive, and other subjects as nonprogressive. Linear and multiple regression analyses were performed to determine factors affecting visual field progression. RESULTS: TD in the superior sector significantly decreased in the subjects overall during the follow-up periods (-0.48 ± 1.92 dB/y, P = 0.025). Linear regression analysis showed that basal MBRT-inferior was correlated significantly with TD-superior slope (r = 0.332, P = 0.002). Furthermore, basal MBRT was significantly lower in this sector in the progressive than the nonprogressive group (P = 0.010). Multiple linear regression analysis revealed that basal MBRT-inferior was the only predictive factor for TD-superior slope (ß = 0.329, P = 0.005). CONCLUSIONS: These findings suggest that superior-sector visual field progression is most common in normotensive PPG eyes, and that reduced basal ONH blood flow is associated with visual field progression. TRANSLATIONAL RELEVANCE: These findings provide new insight into the involvement of ONH blood flow impairment in glaucoma pathogenesis, and demonstrate the importance of assessing ONH blood flow to determine visual field progression in normotensive PPG.

Preperimetric Glaucoma Prospective Observational Study (PPGPS): Design, baseline characteristics, and therapeutic effect of tafluprost in preperimetric glaucoma eye.

PURPOSE: There is no consensus on the diagnosis or treatment policy for Preperimetric Glaucoma (PPG) because the pathogenesis of PPG is not clear at this time. Preperimetric Glaucoma Prospective Observational Study (PPGPS) is a first multicenter, prospective, observational study to clarify the pathogenesis of PPG. This article indicates study design, patient baseline characteristics, and analysis focused on optic nerve head (ONH) blood flow in PPG, as well as the intraocular pressure (IOP) -lowering effect and ONH blood flow-improving effects of Tafluprost. METHOD: In this study, 122 eyes from 122 subjects (mean age: 53.1 ± 14.3) newly diagnosed as PPG were enrolled. The circumpapillary retinal nerve fiber layer thickness (cpRNFLT) was evaluated with optical coherence tomography (OCT). The ONH blood flow was measured with laser speckle flowgraphy. The therapeutic effect of Tafluprost was evaluated at Month 0 (ONH blood flow-improving effect) and Month 4 (IOP-lowering effect). RESULTS: The untreated IOP, cpRNFLT, and baseline Mean deviation (MD) value was 16.4 ± 2.5 mmHg, 80.4 ± 8.2 µm, and -0.48 ± 1.29 dB, respectively. In the site-specific visual field evaluation using the sector map, there was no appreciable site-specific visual field defect in the eye with PPG. The inferior region of cpRNFLT in 4-quadrant OCT sector analysis and 6 o'clock region in 12-o'clock OCT sector analysis was the highest rate of abnormality in PPG eyes. Topical administration of Tafluprost significantly reduced IOP from 16.4 ± 2.5 mmHg at baseline to 14.5 ± 2.3 mmHg at Month 4 (P < 0.001, paired t-test). In the linear regression analysis, there was a significant relationship between the increase of ONH blood flow and baseline value. CONCLUSION: PPGPS is a first prospective study focusing on the pathology of PPG. This study is expected to elucidate the pathology of PPG, with evidence useful for determining a treatment strategy for PPG.

Bullous Exudative Retinal Detachment after Retinal Pattern Scan Laser Photocoagulation in Diabetic Retinopathy.

Laser retinal photocoagulation is the gold standard treatment for diabetic retinopathy. We describe 3 cases in which bullous exudative retinal detachment (ERD) developed after pattern scan laser photocoagulation (PASCAL) in diabetic retinopathy. ERD spontaneously resolved in all 3 cases with various visual courses. This case series highlights 2 key points: first, ERD can occur regardless of gender, age, glycemic control, or vitreous status and despite a moderate number of laser shots, even with PASCAL; second, ERD in nonvitrectomized eyes may cause irreversible visual loss, even if the ERD resolves within 1 month.

Longitudinal changes of ocular blood flow using laser speckle flowgraphy during normal pregnancy.

PURPOSE: Innovative laser speckle flowgraphy (LSFG) enables noninvasive evaluation of retinal microcirculation and the usefulness has been reported in the field of ophthalmology. LSFG has allowed us to measure the real time changes of retinal blood flow without pupillary dilatations and contrast media. Herein, we investigated the change of retinal blood flow in normal pregnant women during gestation using LSFG. METHODS: A prospective cohort study was conducted in 53 pregnant women who visited our institution between January, 2013 and July, 2014. Finally, a total of 41 participants without any obstetric complications were available for evaluation. Retinal blood flow was measured with LSFG in a total of 4 times during pregnancy (T1. 11-13 weeks, T2. 19-21 weeks, T3. 28-30 weeks, T4. 34-36 weeks) and mean blur rate (MBR), blowout score (BOS), flow acceleration index (FAI), and resistive index (RI) are analyzed from these measurements. Relations between LSFG parameters and mean arterial blood pressure (MAP) are determined throughout pregnancy. RESULTS: MBR showed no significant changes throughout pregnancy. BOS showed a tendency to increase in the 3rd trimester. FAI values showed a slight increase from the 1st to 2nd trimester while a significant decrease was noted in the 3rd trimester. RI exhibited no changes between the 1st and 2nd trimesters, values decreased significantly after the 3rd trimester. MAP was positively correlated with BOS, and negatively correlated with FAI and RI. CONCLUSION: The present study clearly demonstrated that profiles of LSFG parameters demonstrated a decrease of resistance in retinal blood vessels. These changes in indices provide a highly sensitive reflection of physiological changes in vascular resistance due to pregnancy. Thus, LSFG may be useful, as a non-invasive, diagnostic tool to detect pregnancy related disorders such as preeclampsia.

Metabolomic profiling of reactive persulfides and polysulfides in the aqueous and vitreous humors.

We investigate the metabolomic profile of reactive persulfides and polysulfides in the aqueous and vitreous humors. Eighteen eyes of 18 consecutive patients with diabetes mellitus (DM) and diabetic retinopathy underwent microincision vitrectomy combined with cataract surgery. Samples of the aqueous and vitreous humors were collected and underwent mass spectrometry-based metabolomic profiling of reactive persulfides and polysulfides (polysulfidomics). The effect of reactive polysulfide species on the viability of immortalized retinal cells (the RGC-5 cell line) under oxidative stress (induced with H2O2) was also evaluated with an Alamar Blue assay. The experiments showed that cysteine persulfides (CysSSH), oxidized glutathione trisulfide (GSSSG) and cystine were elevated in the aqueous humor, and CysSSH, Cys, and cystine were elevated in the vitreous. Furthermore, GSSSG, cystine, and CysSSH levels were correlated in the aqueous and vitreous humors. A comparison, in DM and control subjects, of plasma levels of reactive persulfides and polysulfides showed that they did not differ. In vitro findings revealed that reactive polysulfide species increased cell viability under oxidative stress. Thus, various reactive persulfides and polysulfides appear to be present in the eye, and some reactive sulfide species, which have a protective effect against oxidative stress, are upregulated in the aqueous and vitreous humors of DM eyes.

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

[This corrects the article on p. 3551 in vol. 7, PMID: 27699120.].

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.