Infrared imaging of an A549 cultured cell by a vibrational sum-frequency generation detected infrared super-resolution microscope.

We performed infrared (IR) spectroscopic imaging of molecular species in cultured cell interiors of A549 cells using in-house developed vibrational sum-frequency generation detected IR super-resolution microscope. The spatial resolution of this IR microscope was approximately 1.1 microm, which exceeds the diffraction limit of IR light. Therefore, we clearly observed differences in the signal intensity at various IR wavelengths which appear to originate from the differing IR absorptions of specific vibrational modes, and reveal the distribution of molecular species in the single cell. These results were never imaged with the conventional IR microscope.

Two-point-separation in a sub-micron nonscanning IR super-resolution microscope based on transient fluorescence detected IR spectroscopy.

IR absorption of chemical species in microscopic objects such as biological cells cannot be measured by conventional IR microscopes, because of their low resolution. To overcome this problem, we developed a novel far-field IR super-resolution microscope employing transient fluorescence detected IR spectroscopy. The resolution of this microscope was shown to be 880 nm by measuring the image of 1 microm fluorescent beads. Furthermore, it succeeded in resolving beads located 1.4 microm apart from each other. This is considerably smaller than the diffraction limit of the applied IR light (3.4 microm). These results suggest the capability of our microscope to study sub-micron targets such as sub-cellular structures of biological cells.

Effect of uncompensated corneal polarization on the detection of localized retinal nerve fiber layer defects.

PURPOSE: To investigate the effect of corneal polarization on the detection of retinal nerve fiber layer (RNFL) defects in an artificial eye using scanning laser polarimetry. METHODS: The model eye was composed of a film with a birefringence magnitude of 80 nm (single-pass retardance) in front of a plastic disc with a radial axis of birefringence, which was partially covered with a strip of black paper. The plastic disc, black paper and the film simulated the RNFL, the RNFL defect and the cornea, respectively. The model eye was located at 25 cm from the lens of the Nerve Fiber Analyzer II (NFA II) or GDx with variable corneal compensator (GDx-VCC). Using NFA II, the retardation of the laser beam was measured with/without the artificial cornea in differently simulated corneal birefringence axes that are 15 degrees nasally downward, and 15 degrees nasally upward. Using a GDx, the model eye with/without cornea was measured with a fixed corneal compensator (GDx-FCC) or GDx-VCC. RESULTS: Using NFA II or GDx-FCC, there were three areas in the RNFL thickness profile where an RNFL defect was detected, undetected and reversed. The mean thickness of the RNFL defects was not different from the mean thickness of RNFL in one model eye using NFA II (p = 0.3). Using GDx-VCC, all RNFL defects were detected in all model eye settings. CONCLUSIONS: The influence of incorrect compensation of the anterior segment birefringence is significant. With an FCC, there were particular locations in the retina where the RNFL defects were not detected. The GDx-VCC is a promising tool in glaucoma diagnosis because it detects RNFL defects in any corneal setting.

Efficacy and Safety of Switching Prostaglandin Analog Monotherapy to Tafluprost/Timolol Fixed-Combination Therapy.

PURPOSE: To assess the efficacy and safety of switching from prostaglandin analog (PGA) monotherapy to tafluprost/timolol fixed-combination (Taf/Tim) therapy. SUBJECTS AND METHODS: Patients with primary open-angle glaucoma, normal-tension glaucoma, or ocular hypertension who had received PGA monotherapy for at least 3 months were enrolled. Patients were examined at 1, 2, and 3 months after changing therapies. Subsequently, the patients were returned to PGA monotherapy. The examined parameters included intraocular pressure (IOP) and adverse events. A questionnaire survey was conducted after the switch to Taf/Tim therapy. RESULTS: Forty patients with a mean age of 66.5 ± 10.3 years were enrolled; 39 of these patients completed the study protocol. Switching to Taf/Tim significantly reduced the IOP from 18.2 ± 2.6 mmHg at baseline to 14.8 ± 2.5 mmHg at 1 month, 15.2 ± 2.8 mmHg at 2 months, and 14.9 ± 2.5 mmHg at 3 months (P < 0.001). Switching back to the original PGA monotherapy returned the IOP values to baseline levels. Taf/Tim reduced the pulse rate insignificantly. No significant differences were observed in blood pressure, conjunctival hyperemia, or corneal adverse events. A questionnaire showed that the introduction of Taf/Tim did not significantly influence symptoms. CONCLUSIONS: Compared with PGA monotherapy, Taf/Tim fixed-combination therapy significantly reduced IOP without severe adverse events.

Change in visual acuity and associated risk factors after trabeculectomy with adjunctive mitomycin C.

PURPOSE: To report the 5-year incidence of visual impairment after mitomycin C-augmented trabeculectomy (MMC trabeculectomy) and the risk factors for visual impairment. METHODS: This is a multicentre prospective observational cohort study. Among glaucoma patients registered in the Collaborative Bleb-related Infection Incidence and Treatment Study performed in Japan, the patients with eyes meeting the following qualifications were included: eyes with primary open-angle glaucoma; eyes with primary angle-closure glaucoma; eyes with exfoliative glaucoma; eyes with ≥3/60 in blindness analysis; and eyes with ≥20/60 in low-vision analysis and visual acuity loss analysis. The patients were followed at 6-month intervals for 5 years. The entry data and follow-up data were analysed to determine the incidence of blindness (<3/60), low vision (≥3/60 and <20/60) and visual acuity loss (≥0.2 logMAR) during the follow-up period. Risk factors for visual impairment were also analysed. RESULTS: A total of 694 eyes of 694 or 559 eyes of 559 glaucoma patients were subjected to the blindness analysis or the low-vision and visual acuity loss analysis, respectively. Visual acuity significantly deteriorated (p < 0.0001): 12.2% (95%CI: 9.8-14.7%) of the patients became blind; 12.1% (95%CI: 9.4-14.9%) were judged to have low vision at the final examination; 28.3% (95%CI: 24.5-32.0%) were judged to have visual acuity loss. Glaucoma subtypes, poor preoperative visual function and postoperative complications are the main risk factors for visual impairment. CONCLUSIONS: Visual acuity was significantly reduced after MMC trabeculectomy in 5 years, and we identified several risk factors associated with this complication.

Predicting glaucomatous sensitivity loss using perimetric color saturation test.

PURPOSE: To predict future glaucomatous sensitivity loss using a perimetric color saturation test (PCST) that measures the color saturation discrimination threshold for six hues (red, yellow, green, green-blue, blue, and purple) at 9 degrees in horizontal and 3 degrees in vertical extrafoveal points. METHODS: This new test was carried out on 31 patients (31 eyes) with early glaucoma or ocular hypertension. The sensitivity loss at the four points approximately 9.5 degrees apart from the fixation point was prospectively evaluated annually for 3 years using the Humphrey Field Analyzer (HFA) program central 30-2. The initial results of PCST and the total deviation (TD) in the follow-up HFA results were compared. RESULTS: Twenty-seven patients (27 eyes) were followed up for 3 years. The color saturation threshold for six hues was correlated with the TD of HFA results at 108 points in the 27 eyes. The TD was -4 dB or better at the baseline measurement in 91 out of the 108 points. The averaged TD in the second and the third year in the follow-up period decreased below -4 dB in 10 of these 91 points, which were categorized as progression points in relation to the 81 nonprogression points. In the initial PCST, only the saturation threshold for purple was higher in the progression points when compared with the nonprogression points (P=.0004, Mann-Whitney U-test). CONCLUSION: Future sensitivity loss is most likely at the points where the threshold of color saturation discrimination is increased for purple in eyes with early glaucoma or ocular hypertension.

A prospective study of iridial pigmentation and eyelash changes due to ophthalmic treatment with latanoprost.

PURPOSE: To conduct a 12-month prospective study on the occurrence of latanoprost-induced iridial pigmentation and eyelash change in Japanese patients with glaucoma METHODS: Seventy-five patients (75 eyes) were enrolled in the study. Photographs of the iris and eyelashes were taken under identical conditions before and after treatment. Three glaucoma specialists assessed the iridial pigmentation/eyelash change independently with no knowledge of patient data. The effects of age, sex, concomitant medication, and type of glaucoma on iridial pigmentation/eyelash change were investigated, and intraocular pressure (IOP) reduction and iridocorneal angle pigmentation before and after latanoprost treatment were compared between patients with iridial pigmentation/eyelash change and patients without these changes. RESULTS: The incidence of iridial pigmentation was 6.3% at 1 month, 15.7% at 3 months, 37.8% at 6 months, and 56.5% at 12 months. The incidence of eyelash change was 0% at 1 month, 33.8% at 3 months, 44.4% at 6 months, and 46.2% at 12 months. Latanoprost did not affect IOP reduction or iridocorneal angle pigmentation. No significant relationship between iridial pigmentation and eyelash change was observed. None of the investigated parameters except age affected the iridial pigmentation/eyelash change. CONCLUSION: Iridial pigmentation and eyelash change occurred at a high frequency in long-term treatment with latanoprost in Japanese glaucoma patients.

[Reliable parameters for assessing the birefringence of retinal nerve fiber layer under various conditions of corneal birefringence].

PURPOSE: To find a reliable parameter for the assessment of parafoveal nerve fiber layer using scanning laser polarimetry. METHODS: The retinal nerve fiber layer was imaged using a Nerve Fiber Analyzer II (NFA II) along the parafoveal circle with a 90-pixel diameter in 4 dilated eyes of 4 normal subjects. The average thickness was measured in the superior(S), temporal(T), inferior(I), and nasal(N) quadrants. The image was obtained by means of a laser beam passing through 4 different locations in the cornea: the center, 2 mm temporal from the center, 2 mm lower temporal from the center, and 2 mm lower from the center. RESULTS: The circumference profile of the nerve fiber layer around the fovea showed a biphasic pattern similar to that obtained around the optic disc. However, the peaks of the pattern varied according to the corneal location through which the laser beam passed. Accordingly, the average thickness of the nerve fiber layer in each quadrant showed great fluctuation when using a displaced laser beam. The coefficient of variance was large (0.265-0.313) for the nerve fiber layer thickness itself; however, it was far less for the ratio of the nerve fiber layer thickness in the opposite direction, such as temporal-to-nasal (0.082) or superior-to-inferior (0.089). CONCLUSIONS: Although the measurement of the retinal nerve fiber thickness itself depends largely on the location in the birefringent cornea through which the laser beam passes, the ratios of nerve fiber layer thickness such as temporal-to-nasal or superior-to-inferior are reliable and show less fluctuation in the measured values.

Comparison of the anterior ocular segment measurements using swept-source optical coherent tomography and a scanning peripheral anterior chamber depth analyzer.

PURPOSE: To compare the anterior ocular segment measurements of two non-contact devices, i.e., anterior segment swept-source optical coherence tomography (SS-OCT) and the scanning peripheral anterior chamber depth analyzer (SPAC), in patients with glaucoma. PATIENTS AND METHODS: This was a cross-sectional study of glaucoma patients visiting the Yamanashi University Hospital. The consistency and correlation of various parameters were studied between the SS-OCT and SPAC measurements, including the central corneal thickness (CCT), the central anterior chamber depth (ACD), the trabecular-iris angle (TIA), the angle opening distance (AOD), the area of the recessed angle (ARA), and the trabecular-iris space area (TISA) from the SS-OCT measurements, and the CCT, central ACD, SPAC grade, and SPAC-evaluated anterior chamber angle (ACA) from the SPAC measurements. RESULTS: Seventy right eyes of 70 patients (27 men, 43 women) with glaucoma were enrolled in the study. The mean patient age was 65.9 ± 14.5 years. The CCT measurements by SS-OCT and the SPAC were 528.3 ± 32.0 and 516.1 ± 28.5 µm, respectively (P < 0.001). The central ACD measurements by SS-OCT and the SPAC were 2.39 ± 0.44 and 2.73 ± 0.50 mm, respectively (P < 0.001). The two devices showed a significant correlation in terms of the CCT measurements (R (2) = 0.667, P < 0.0001) and the central ACD measurements (R (2) = 0.86, P < 0.0001), but SS-OCT give a significantly shallower central ACD measurement and a thinner CCT measurement compared with the SPAC. AOD, TIA, TISA, and the ARA were all significantly correlated with the SPAC grade and the ACA. Consistency between the two devices was reduced among eyes with primary angle closure. CONCLUSIONS: Based on our results, the SS-OCT and SPAC measurements of the anterior segment were significantly correlated, but the values cannot be considered to be directly interchangeable.