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

Structural impairment patterns in peripapillary retinal fiber layer and retinal ganglion cell layer in mitochondrial optic neuropathies

AIM：To evaluate the structural injure patterns in peripapillary retinal fiber layer （pRNFL）, retinal ganglion cell layer （RGCL） and their correlations to visual function in various mitochondrial optic neuropathies （MON） to offer help to their differential diagnosis.METHODS：Totally 32 MON patients （60 eyes） were recruited within 6mo after clinical onsets, including 20 Leber hereditary optic neuropathy （LHON） patients （37eyes）, 12 ethambutol-induced optic neuropathy （EON）patients （23 eyes）, and 41 age-gender matched healthy controls （HC, 82 eyes）. All subjects had pRNFL and RGCL examinations with optic coherence tomography （OCT） and visual function tests.RESULTS：In the early stages of MON, the temporal pRNFL thickness decreased （66.09±22.57μm）, but increased in other quadrants, compared to HC （76.95±14.81μm）. The other quadrants remaining stable for LHON and EON patients besides the second hour sector of pRNFL thickness reduced and the temporal pRNFL decreased （56.78±15.87μm） for EON. Total macular thickness in MON reduced remarkably（279.25±18.90μm; P=0.015）, which mainly occurring in the inner circle （3 mm diameter of circle） and the nasal temporal sectors in the outer circle （5.5 mm diameter of circle）, in contrast to those in HC. RGCL thickness reduced in each sector of the macula （61.90±8.73μm; P≤0.001）. It strongly showed the correlationship of best corrected visual acuity （R=0.50, P=0.0003） and visual field injury （R=0.54,P=0.0002） in MON patients.CONCLUSION：OCT is a potential tool for detecting structural alterations in the optic nerves of various MON. Different types of MON may have different damage patterns.

Activation of Parvalbumin-Positive Neurons in Both Retina and Primary Visual Cortex Improves the Feature-Selectivity of Primary Visual Cortex Neurons

Several recent studies using either viral or transgenic mouse models have shown different results on whether the activation of parvalbumin-positive（PV~＋）neurons expressing channelrhodopsin-2（ChR2） in the primary visual cortex（V1） improves the orientation-and direction-selectivity of V1 neurons. Although this discrepancy was thoroughly discussed in a follow-up communication, the issue of using different models to express ChR2 in V1 was not mentioned. We found that ChR2 was expressed in retinal ganglion cells（RGCs） and V1 neurons in ChR2fl/~＋; PV-Cre mice. Our results showed that the activation of PV~＋RGCs using white drifting gratings alone significantly decreased the firing rates of V1 neurons and improved their direction-and orientation-selectivity. Longduration activation of PV~＋interneurons in V1 further enhanced the feature-selectivity of V1 neurons in anesthetized mice, confirming the conclusions from previous findings. These results suggest that the activation of both PV~＋RGCs and V1 neurons improves feature-selectivity in mice.