Effect of infusion pressure during cataract surgery on ganglion cells measured using isolated-check visual evoked potential

AIM： To detect the relationship between infusion pressure and postoperative ganglion cells function.METHODS： This prospective observational cohort study included sixty-one eyes that underwent uncomplicated cataract surgery. Patients were divided into two groups according to infusion time（IT） recorded using surgery equipment [Group A： IT〉IT_（mean）（27 eyes）; Group B： IT

Visual Passive Ranging Method Based on Re-entrant Coaxial Optical Path and Experimental Verification

To overcome the shortcomings of the traditional passive ranging technology based on image, such as poor ranging accuracy, low reliability and complex system, a new visual passive ranging method based on re-entrant coaxial optical path is presented. The target image is obtained using double cameras with coaxial optical path. Since there is imaging optical path difference between the cameras, the images are different. In comparison of the image differences, the target range could be reversed. The principle of the ranging method and the ranging model are described. The relationship among parameters in the ranging process is analyzed quantitatively. Meanwhile,the system composition and technical realization scheme are also presented. Also, the principle of the method is verified by the equivalent experiment. The experimental results show that the design scheme is correct and feasible with good robustness. Generally, the ranging error is less than 10% with good convergence. The optical path is designed in a re-entrant mode to reduce the volume and weight of the system. Through the coaxial design,the visual passive range of the targets with any posture can be obtained in real time. The system can be widely used in electro-optical countermeasure and concealed photoelectric detection.

Real-life experience of ranibizumab therapy for neovascular age-related macular degeneration from Turkey

AIM： To report the real-life experience and clinical results of intravitreal ranibizumab injections to neovascular agerelated macular degeneration（nAMD） in a single institution in Turkey.METHODS： A total of 101 eyes of 89 patients with nAMD treated with intravitreal ranibizumab injection, followed up for at least 24 mo between 2009 and June 2014, which were evaluated retrospectively. A pro re nata（PRN） treatment protocol was performed after the patients had received three, monthly loading injections. Best corrected visual acuity（BCVA） and central macular thickness measurements were evaluated at baseline and 3, 6, 12, 18, and 24 mo. Number of injections and visits were also recorded.RESULTS： Of the 89 patients, 34（38.2%） were male and 55（61.8%） were female and the mean age was 74.0±9.5（52-91）y. The mean follow-up period was 24.82±4.4（24-29）mo. Mean number of visits was 8.4±1.12（7-12） in the first year and 6.6±1.33（4-12） in the second year. The mean number of injections was 5.8±1.6（3-10） and 4.2±2.2（0-9） in the first and second year, respectively. The mean BCVA was 59±15.8 letters at baseline by the Early Treatment Diabetic Retinopathy Study（ETDRS） chart. The mean BCVA at 3, 12, and 24 mo was 70.3±15.9, 67.9±14.3 and 67.3±16.9 letters, respectively. Improvement in visual acuity for each of the visits from baseline was found to be statistically significant（P〈0.01）. Visual acuity in 9 eyes at month 3, 7 eyes at month 12, and 13 eyes at month 24 did not change. The mean central macular thickness（CMT） was 437.99±164.78 μm at baseline. The mean CMT was 348.05±138.47 μm, 349.27±139.79 μm, and 344.13±146.30 μm at months 3, 12, and 24, respectively. The decrease in CMT for each of the visits from baseline was found to be statistically significant（P〈0.01）.CONCLUSION： Anatomical and functional achievement are obtained in our study, but the mean number of injections and visits are found to be lower than the findings reported in randomized controlled clinical trials in the literature. However, the mean number of injections and visits in our study are compatible with the findings reported in real-life experience studies in the literature.

Objective visual performance evaluation with visual evoked potential measurements based on an adaptive optics system

An objective visual performance evaluation with visual evoked potential （VEP） measurements was first inte- grated into an adaptive optics （AO） system. The optical and neural limits to vision can be bypassed through this system. Visual performance can be measured electrophysiologically with VEP, which reflects the objective func- tion from the retina to the primary visual cortex. The VEP ts without and with AO correction were preliminarily carried out using this system, demonstrating the great potential of this system in the objective visual performance evaluation. The new system will provide the necessary technique and equipment support for the further study of human visual function.

Mechanism of delayed conduction of fellow eyes in patients with optic neuritis

To test the hypothesis that latency delay in the fellow eyes of optic neuritis（ON） patients and to compensate for delayed transmission of visual information, latency change of multi-focal visual evoked potential（mf VEP） traces in fellow eyes of 15 ON patients were analyzed. Patients with low risk（LR） for developing multiple sclerosis（MS） were examined separately from MS patients to isolate effect of cortical plasticity from potential pathological changes in disseminated disease. The small increase in latency in fellow eyes of LR group was statistically not significant. In MS patients, the latency was significantly delayed（P〈0.02）. The magnitude of the latency change in the fellow eyes did not correlate with the severity of latency delay in the affected eyes（R^2〈0.02, P=0.3）. The differences between ON patients with and without MS, reported here, suggest that the presence of disseminated disease plays critical role in latency delay of the fellow eye.

Optical visualization and polarized light absorption of the single-wall carbon nanotube to verify intrinsic thermal applications

The predicted extraordinary properties of carbon nanotubes(CNTs)from theoretical calculations have great potential for many applications.However,reliable experimental determination of intrinsic properties at the single-tube level is currently a matter of concern,and many challenges remain because of the unhandled and nanoscale size of individual nanotubes.Here,we demonstrated a prototype to detect the intrinsic thermal conductivity of the single-wall carbon nanotube(SWCNT)and verify the significant non-resonant optical absorption behavior on tiny nanotubes by integrating the nanotube and ice into a new core-shell design.In particular,a reversible optical visualization method based on the individual suspended ultra-long SWCNT was first developed by wrapping a nanotube with ice in the cryogenic air environment.The light-induced thermal effect on the hybrid core-shell structure was used tomelt the ice shell,which subsequently acted as a temperature sensor to verify the intrinsic thermal conductivity of the core-like nanotube.More interestingly,we successfully determined for the first time the thermal response phenomenon of the tiny absorption cross section in SWCNT in the vertical-polarization configuration and the significant non-resonant absorption behavior in the parallel-polarization configuration.These investigations will provide a better understanding for the unique optical behaviors of CNT and enable the detection of intrinsic properties of various one-dimensional nanostructures such as nanotubes,nanowires,and nanoribbons.

Endoscopic decompression of the optic canal for traumatic optic neuropathy

Purpose： Traumatic optic neuropathy （TON） is a serious complication of head trauma with the incidence rate of 0.5%-5%. The aim of this study was to investigate the therapeutic efficacy of endoscopic decompression of the optic canal for optic nerve injuries. Methods： In this study, 11 patients treated in our hospital from January 2009 to January 2015 with the visual loss resulting from TON were retrospectively reviewed for preoperative vision, visual evoked potential （VEP） scan, surgical approach, postoperative visual acuity, complications, and follow-up results. Results： All these patients received endoscopic decompression of the optic canal. At the 3-month follow- up, the visual acuity improvement rate of the 11 patients was 45.5%. The vision acuity of 2 cases improved from hand movement to 0.08 and 0.3 after operation. Another patient＇s vision acuity returned to 0.05 compared to light sensation preoperatively. Two cases had finger counting before surgery but they had a vision acuity of 0.4 and light sensation respectively after surgery. However, the other 6 cases＇ vision did not improve after surgery. Conclusion： Endoscopic decompression of the optic canal is an effective way to cure TON. VEP could be used as an important reference for preoperative and prognosis evaluation. Operative time after trauma is only a relative condition that may affect the therapeutic effect of optic canal decompression. Poor results of this procedure may be related to the severity of the optic nerve injury.

In-Vitro and In-Vivo Electrical Characteristics of a Penetrating Microelectrode Array for Optic Nerve Electrical Stimulation

The Chinese C-Sight team aims to restore vision to blind patients by means of stimulating the optic nerve with a penetrating microelectrode array. A biocompatible, implantable microwire array was developed having four platinum-iridium shafts, each 100μm in diameter. This penetrating microwire array is described in this paper, including its fabrication techniques and its in-vitro electrical characteristics. Every set of four shafts was spaced 0.4mm from center to center, comprising two short shafts that were 0.3mm long and two that were 0.9mm long. This design was intended to stimulate ganglion cell axons at different depths within the optic nerve. In-vitro electrochemical impedance testing results showed that the impedance at 1kHz ranged from 8 to 10kΩ at room temperature. The voltage responses of the arrays to current pulse stimulation indicated a charge-injection capacity of 210μC/cm2. Finally, in-vivo acute animal experiments showed that the amplitude of the electrically evoked potentials (EEPs) measured in primary visual cortex could be as large as 100 μV upon direct stimulation of the optic nerve.