Depth Perception with a Newly Developed Microscope Stereotest.

PURPOSE: We aimed to compare the depth perception under a microscope between binocular and monocular conditions using a newly developed microscopic stereotest (M-stereotest) and examine the effect of anisometropia on depth perception under a microscope. SUBJECTS AND METHODS: Thirty young and healthy subjects were examined. A manipulator attached with a stainless wire was placed under the objective lens of a stereomicroscope. The wire was moved up manually, and the subjects were instructed to stop the knob movement once the wire reached the same height as the fixed two wires. The deviation from the height of the fixed wires was measured under a best optically corrected binocular, a best optically corrected monocular, or an anisometropic binocular [±3 diopters (D) in the dominant or nondominant eye] condition. RESULTS: The deviation was significantly smaller in the binocular condition than in the monocular dominant eye condition (0.38 ± 0.26 mm vs 1.89 ± 1.15 mm, p < 0.001) and was also significantly smaller in the best optically corrected binocular than in the anisometropic binocular condition [1.07 ± 1.00 mm (-3.0 D), p = 0.003; 0.85 ± 0.67 mm (+3.0 D), p < 0.001]. CONCLUSION: Depth perception under the microscope is more accurate under the binocular than in the monocular condition, indicating the potential role of stereopsis. Anisometropia deteriorates depth perception, suggesting that refractive error should be corrected during microscopic work, such as during ophthalmic surgery.

Best surgical technique and outcomes for large macular holes: retrospective multicentre study in Japan.

The purpose of this study was to compare the surgical outcomes of vitrectomy with conventional internal limiting membrane (C-ILM) peeling to that with the inverted ILM (I-ILM) flap technique for large macular holes (MHs). This was a retrospective chart review of consecutive cases with a large MH at nine hospitals in Japan. Among the 1342 eyes, 165 eyes of 165 cases met the inclusion criteria. The results for medium-large MHs with a diameter 400-550 µm were compared to that of eyes with an extra-large MH with a diameter >550 µm. In addition, the results of C-ILM peeling were compared to that of the I-ILM technique. In medium-large MHs, the closure rate was 95.2% (59/62) by C-ILM peeling and 100% (19/19) by the I-ILM technique. In extra-large MHs, the closure rate was 88.4% (38/43) by C-ILM peeling and 100% (41/41) by I-ILM. Although the difference between the two methods was not significant, the I-ILM technique was successful in 100% of the cases. Multiple logistic regression analysis showed the best-corrected visual acuity (BCVA) at 6 months was significantly associated with the preoperative BCVA, MH size, age and sex of the patient. Analyses of the eyes with extra-large MHs show that the surgical success is high, and the I-ILM technique is more effective for closure in eyes with extra-large MHs.

Diurnal variations in luminal and stromal areas of choroid in normal eyes.

AIMS: To determine the diurnal variations of the luminal and stromal areas of the choroid in normal eyes. METHODS: This was a prospective observational study of 38 eyes of 38 normal subjects. The blood pressure, heart rate, intraocular pressure and enhanced depth imaging optical coherence tomographic (EDI-OCT) images were recorded every 3 hours between 6:00 and 21:00 hours. The horizontal EDI-OCT images of the subfoveal choroid were converted to binary images. The central choroidal thickness (CCT), total cross-sectional choroidal area, the luminal areas, stromal areas and the ratio of luminal area to total choroidal area (L/C ratio) were determined. RESULTS: There were significant diurnal variations in the CCT, total choroidal area, luminal area and L/C ratio with the maximum values at 6:00 hours and the minimum values at 15:00 hours (p<0.001 for the CCT, p=0.011 for the total choroidal area, p<0.001 for the luminal area and p=0.014 for the L/C ratio). There was no significant variation in the stromal area (p=0.216). The range of fluctuation in the CCT was significantly correlated with that in the luminal area and the total choroidal area (p<0.001). However, there was no significant correlation between the fluctuation range in the CCT and that in the stromal area (p=0.095). There was no statistical relationship between the systemic parameters and the choroidal parameters. CONCLUSIONS: The changes in the luminal area are most likely responsible for the diurnal change in the CCT and subfoveal choroidal area. TRIAL REGISTRATION NUMBER: UMIN000019060, Pre-results.

B-type (brain) natriuretic peptide and pruritus in hemodialysis patients.

INTRODUCTION AND OBJECTIVE: While pruritus is a common complication in hemodialysis patients, the pathophysiological mechanisms remain obscure. Recently, B-type (brain) natriuretic peptide (BNP) has been defined as an itch-selective neuropeptide in pruriceptive neurons in mice, and higher serum levels of BNP are frequently observed in hemodialysis patients. The objective of the present study was to evaluate the role of serum BNP in pruritus in patients undergoing hemodialysis. PATIENTS AND METHODS: The current cross-sectional study was performed on 43 patients undergoing maintenance hemodialysis. A visual analog scale (VAS) measuring the general severity of pruritus (values from 0 to 10, with higher values indicating more severe pruritus) in daytime and at night was self-reported by patients. Each patient's background and laboratory tests, including serum BNP in the post-hemodialysis period, were collected. The correlation between VAS and clinical parameters was evaluated. RESULTS: Both daytime and nighttime VAS scores in diabetic patients were significantly less than those in nondiabetic patients. Multiple regression analysis revealed that pruritus in daytime was worsened by serum BNP (ß=2.0, t=2.4, P=0.03), calcium (ß=4.4, t=5.2, P<0.0001), and ß2-microglobulin (ß=2.0, t=3.0, P=0.007), while it was eased by age (ß=-2.2, t=-3.2, P=0.0004). Nocturnal pruritus was severe in nondiabetic patients (ß=1.7, t=3.8, P=0.0005) and weakened by the total iron binding capacity (ß=-2.9, t=-3.1, P=0.004). CONCLUSION: It is suggested that a higher level of serum BNP increases the pruritus of hemodialysis patients in daytime and that diabetic patients are less sensitive to itch, especially at nighttime.

Molecular genetic investigations of contaminated contact lens storage cases as reservoirs of Pseudomonas aeruginosa keratitis.

PURPOSE: To elucidate the reservoirs of Pseudomonas aeruginosa keratitis associated with contact lens (CL) wear by using a molecular genotyping method. METHOD: Ten P. aeruginosa isolates obtained from two young adult patients with infectious keratitis associated with CL wear were studied. These were isolated from corneal specimens, conjunctival swabs, discharges, CL storage cases, and the living environment of the two patients. Species identification was performed with an Oxi/Ferm Tube II system using well-separated colonies on MacConkey and NAC agar plates. We employed molecular genotyping by pulsed-field gel electrophoresis. RESULTS: We isolated three (one each from a corneal scraping, discharge, and a CL storage case) P. aeruginosa samples from patient 1, and seven (one each from the conjunctival swab, CL storage case, and the patient's fingers, and four from the patient's room) from patient 2. Pseudomonas aeruginosa of environmental origin could not be obtained from the house of patient 1. The genotypes of two P. aeruginosa isolates, from corneal scraping and discharge, were identical to that of the isolate from the CL storage case belonging to patient 1. In patient 2, the isolates from the eye and the CL storage case showed the identical genotype, which was different from those of the environmental isolates. CONCLUSION: Our results suggest that the causative P. aeruginosa strains in cases of infectious keratitis associated with CL wear originate in contaminated CL storage cases. However, it is still unclear whether the environmental strains in the patients' houses also cause keratitis.