Effect of Bergmeister papilla on disc parameters in spectral domain optical coherence tomography.

OBJECTIVES: To investigate the morphological characteristics of Bergmeister papilla (BMP), a persistent hyaloid remnant tissue, and its effects on the measurements and repeatability of spectral-domain optical coherence tomography (OCT). SUBJECTS/METHODS: The subjects of this prospective cross-sectional study including 83 patients with BMP and 76 unaffected individuals, all had open-angle structures. Images, including a 5-line raster and three consecutive optic disc cube scans centred on the optic disc, were acquired using the Cirrus high-definition OCT. BMP's structural characteristics were classified based on the raster scan images, and repeatability of acquiring optic nerve head and retinal nerve fibre layer parameters acquisition was analysed by calculating the test-retest standard deviation (Sw), coefficient of variance (CV), and intraclass correlation coefficient. RESULTS: BMPs (n = 83) were categorised into lifting edge (LE) type (63.9%, n = 53), which partially covers the edge of the optic nerve head, and covering disc (CD) type (36.1%, n = 30), which completely covers the cupping area like a cap. The average cup-to-disc ratio (0.58 ± 0.21), vertical cup-to-disc ratio (0.55 ± 0.21), and cup volume (0.22 ± 0.22) of the CD type were lower than those of the LE type (0.66 ± 0.13, 0.64 ± 0.13, and 0.4 ± 0.27, respectively; all P < 0.05). Tolerability indices for repeatability of cup volume (Sw = 0.40 and CV = 0.36) and inferonasal (4 o'clock) retinal nerve fibre layer (Sw = 0.27 and CV = 0.25) in LE-type BMPs exceeded the cut-off value (0.22) and demonstrated stronger correlation with BMP location than that of the controls. CONCLUSION: Caution should be exercised when interpreting OCT findings in eyes with BMP, as BMP can introduce a pitfall in OCT imaging.

Highly efficient and robust noble-metal free bifunctional water electrolysis catalyst achieved via complementary charge transfer.

The operating principle of conventional water electrolysis using heterogenous catalysts has been primarily focused on the unidirectional charge transfer within the heterostructure. Herein, multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La0.5Sr0.5CoO3-δ, LSC) and potassium ion-bonded MoSe2 (K-MoSe2). The complementary charge transfer from LSC and K to MoSe2 endows MoSe2 with the electron-rich surface and increased electrical conductivity, which improves the hydrogen evolution reaction (HER) kinetics. Excellent oxygen evolution reaction (OER) kinetics of LSC/K-MoSe2 is also achieved, surpassing that of the noble metal (IrO2), attributed to the enhanced adsorption capability of surface-based oxygen intermediates of the heterostructure. Consequently, the water electrolysis efficiency of LSC/K-MoSe2 exceeds the performance of the state-of-the-art Pt/C||IrO2 couple. Furthermore, LSC/K-MoSe2 exhibits remarkable chronopotentiometric stability over 2,500 h under a high current density of 100 mA cm-2.

Large exotropia after retrobulbar anesthesia.

A 67-year-old woman complained of horizontal diplopia shortly following bilateral cataract surgery with intraocular lens implantation performed under retrobulbar anesthesia. Retrobulbar anesthesia was administered at an inferotemporal injection site using 1 cc lidocaine hydrochloride 2% mixed with bupivacaine hydrochloride 0.5%. The initial ophthalmologic evaluation showed a 12-prism diopter (PD) exotropia, and ocular motility evaluation revealed marked limitation of adduction without vertical limitation. One year after cataract surgery, the exodeviation increased up to 60 PD. The patient underwent an 8.0-mm recession of the right lateral rectus and a 6.0-mm recession of the left lateral rectus. Both lateral rectus muscles were biopsied, and biopsy revealed dense fibrous connective tissue without viable muscular cells. The lateral rectus muscle might be injured by retrobulbar anesthesia, and it could induce large exotropia.

Biometry and spectral domain optical coherence tomography parameters in children with large cupping.

PURPOSE: The purpose of this study is to investigate optic nerve head using spectral domain optical coherence tomography (SD-OCT) in children with large cupping. METHODS: 111 eyes (4-10 years) were divided into three groups according to the cup to disc ratio: group 1, ≤0.3; group 2, 0.4-0.6; and group 3, ≥0.7. The rim area, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume were investigated using SD-OCT (Cirrus HD-OCT, Carl Zeiss, Jena, Germany), and the axial length and anterior chamber depth (ACD) were measured by IOL master (IOL master 500, Carl Zeiss, Jena, Germany). Next, we compared ocular biometry and SD-OCT between the three groups. RESULTS: The mean age of group 1 was 6.48 ± 1.42 years, 7.00 ± 1.75 years in group 2, and 6.63 ± 1.82 years in group 3 (p = 0.370). A significant difference was seen in the spherical equivalent between the groups (p = 0.001). Group 2 had the most myopic refractive errors. As the cup to disc ratio increases, disc area, average cup to disc ratio, vertical cup to disc ratio, and cup volume increase significantly. When the results of ocular biometry and SD-OCT are adjusted for axial length, only disc area showed a significant correlation with cup to disc ratio (ACD: p = 0.473, rim area: p = 0.639, disc area: p = 0.005, and cup volume: p = 0.325). CONCLUSION: Axial length is the key factor determining disc size, which in turn is important for determining cup to disc ratio. Normal children with large cupping should be examined for axial length, myopic refractive errors, and disc size.

Quantitative analysis of optic disc color.

PURPOSE: To evaluate the reproducibility of ImageJ software in analyzing the color of the optic disc. METHODS: One hundred twelve normal participants (56 males and 56 females) were enrolled in this study. The image of the optic disc was taken using Kowa digital disc photo-graphy, and the gray scales of the nasal rim (NR), brightest cupping center (BCC) and largest inferior retinal vein (IRV) were calculated using histogram in ImageJ. Three different observers calculated the gray scales three separate times. Reproducibility was assessed using the interclass correlation coefficient (ICC). RESULTS: The mean age of the participants was 50.6 years old (range, 11 to 82 years). The mean gray scales of the nasal rim were 91.81, 94.91, and 93.24; those of the brightest cupping center were 174.84, 179.94, and 177.76; and those of the largest inferior retinal vein were 61.85, 53.48, and 56.73 for observers 1, 2, and 3, respectively. Inter-observer reproducibility for NR, BCC and IRV was considered good based upon ICC values of 0.944, 0.860, and 0.789 for observers 1, 2, and 3, respectively. Significant age-related differences between the values of the brightest cupping center were noted, and the gray scale score was decreased in the older participants (p < 0.001). CONCLUSIONS: The gray scale of the brightest cupping center diminished with age. ImageJ can be a useful objective tool with high reproducibility in the analysis of optic disc color.