Pattern-reversal retinal potentials(PRRP) are electrical signals generated within retina, possibly by the retinal ganglion cells, when a phase-alternating check board pattern is viewed. Authors clinically studied the characteristics of PRRP the mean amplitude and latency with 24 minute checks, the effect of the spatial frequency, the effect of defocusing and the retinocortical time in 20 normals, using Nicolet CA 1,000. The results are as follows; 1. The mean latency P1 and the mean P1-N2 amplitude of PRRP in normal group was 39.19 +/- 3.30(msec), 1.32 +/- 0.22(uV), respectively. 2. The mean retinocortical time in normal group was 52.93 +/- 7.39(msec). 3. The P1-N2 amplitude of PRRP was reduced linearly with increasing defocusing, and significant amplitude reduction was observed when defocusing amounted to +1D. 4. When central 3 degree of stimulus was covered in order to simulate a macular pathology, PRRP to 24 minute checks was abnormal both in amplitude and latency. 5. Peak response amplitude of PRRP was obtained with large checksizes(3 degrees 12 minutes, 6 degrees 24 minutes).
Pathology ; Retina ; Retinal Ganglion Cells ; Retinaldehyde*

In vertebrate visual system, retina is the first stage for visual information processing. Retinal ganglion cells are the only output neurons of the retina, and their firing activities are dependent on visual stimuli. Retinal ganglion cells can effectively encode visual information via various manners, such as firing rate, temporal structure of spike trains, and concerted activity, etc. Adaptation is one of the basic characteristics of the nervous system, which enables retinal neurons to encode stimuli under a wide variety of natural conditions with limited range in their output. This article reviews the recent studies focused on the coding properties and adaptation of retinal ganglion cells. Relevant issues about dynamical adjustment of coding strategies of retinal ganglion cells in response to different visual stimulation, as well as physiological property and function of adaptation are discussed.
Photic Stimulation ; Retina ; Retinal Ganglion Cells

As part of Korean retinal prosthesis project, we have provided preliminary experimental results regarding voltage parameters for the stimulation of chemically degenerated rabbit retina. Since our APB-treated chemically degenerated retina is only ON-pathway blocked, now we switch our experiments to more appropriate retinal degeneration model, genetically degenerated retina model (RD mouse: rd/rd (C3H/HeJ)). Before studying with RD mouse, we started control experiments with normal SD rat to understand characteristics of retinal ganglion cell activity with postnatal maturation in rodents. Ganglion cell activities were recorded with 8x8 multi-electrode array. Moving spontaneous bursts appeared until postnatal day of 15. During pre-eye opening period, no light evoked response appeared. After postnatal day of 2 weeks (post-eye opening period), ON-, OFF- and ON/OFF response appeared. The fractional distributions of ON, OFF, and ON/OFF ganglion cell is about 40%, 50%, and 5%. The percentage (%) of light evoked response in each dorso-temporal, ventral, and dorso-nasal area of eye is about 50%, 37.5% and 12.5%, respectively. We concluded that the optimal period for experiment in rodent is about postnatal day of 2~3 weeks.
Animals ; Ganglion Cysts ; Mice ; Rats* ; Retina ; Retinal Degeneration ; Retinal Ganglion Cells* ; Retinaldehyde* ; Rodentia ; Visual Prosthesis

Retinal implants have been developed as a promising way to restore partial vision for the blind. The observation and analysis of neural activities can offer valuable insights for successful prosthetic electrical stimulation. Retinal ganglion cell (RGC) activities have been investigated to provide knowledge on the requirements for electrical stimulation, such as threshold current and the effect of stimulation waveforms. To develop a detailed ‘stimulation strategy’ for faithful delivery of spatiotemporal visual information to the brain, it is essential to examine both the temporal and spatial characteristics of RGC responses, whereas previous studies were mainly focused on one or the other. In this study, we investigate whether the spatiotemporal visual information can be decoded from the RGC network activity evoked by patterned electrical stimulation. Along with a thorough characterization of spatial spreading of stimulation current and temporal information encoding, we demonstrated that multipixel spatiotemporal visual information can be accurately decoded from the population activities of RGCs stimulated by amplitude-modulated pulse trains. We also found that the details of stimulation, such as pulse amplitude range and pulse rate, were crucial for accurate decoding. Overall, the results suggest that useful visual function may be restored by amplitude modulation-based retinal stimulation.
Brain ; Electric Stimulation* ; Heart Rate ; Retinal Ganglion Cells ; Retinaldehyde*

PURPOSE: The purpose of this study was to review previous literature with an aim to explore the sleep disturbance level after a patient undergoes cataract surgery using an integrative review. METHODS: We used the key words, ‘cataract surgery’, ‘sleep’, and ‘intraocular lens’ to find peer-reviewed publications in seven databases. Among 450 searched articles, eight articles were selected after exclusion of articles that did not meet the criteria. RESULTS: Five of the articles submitted that subjective sleep quality of the patients with blue-filtering intraocular lens (BF-IOL) implant improved as compared to that before surgery. The change of saliva melatonin concentration after BF-IOL implant did not coincide in two of the articles. Two of the articles reported an increased level of intrinsically photosensitive retinal ganglion cells response after BF-IOL implantation. CONCLUSION: The published studies stated that BF-IOL implant did not have any negative impact on quality of sleep among cataract patients suffering with poor sleep. Rregardless of intraocular lens type, cataract surgery may increase photoreception of intrinsically photosensitive retinal ganglion cells one year after surgery although the mechanism was not clear. It is necessary to identify various factors influencing the quality of sleep such as gender and activities among cataract patients with BF-IOL implant in the future.
Cataract ; Humans ; Lenses, Intraocular ; Melatonin ; Retinal Ganglion Cells ; Saliva

PURPOSE: There were many studies on the distributions of the retinal ganglion cells(RGC) in the experimental model of the retinal ischemia. RGC was known to be more sensitive to the ischemic injury than the other types of the retinal cells. So, we would identify the changes of the retinal ganglion cell morphologies and distribution after the iatrogenic retinal ischemia induced by intraocular pressure(IOP) elevation. METHODS: Eight pigmented and six white rabbits were used and retinal ischemia was induced by increasing IOP higher than 120 mmHg for 60 minutes. Electroretinogram were recorded at 6 days or 13 days, and histologic findings were observed at 7 or 14 days. RESULTS: After 7 days, RGC densities decreased, cytoplasmic staining disappeared, and the intranuclear hyperpigmentation was noted. RGC densities decreased significantly at 14 days. In the vertical retinal section, some flattening of retinal ganglion cell layer and inner plexiform layer was observed. Changes in the cellular morphologies were prominent. CONCLUSIONS: It may be more appropriate to examine both the retinal whole-mount and the vertical tissue section for the estimatation of the changes of retinal ganglion cell layer in the pressure-induced retinal ischemia.
Cytoplasm ; Ganglion Cysts* ; Hyperpigmentation ; Ischemia ; Models, Theoretical ; Rabbits ; Retina* ; Retinal Ganglion Cells ; Retinaldehyde*

PURPOSE: To determine the loss of ganglion cell layer (GCL) neurons in patients with age-related macular degeneration (AMD) with choroidal neovascularization (CNV). METHODS: Retinal nerve fiber layer (RNFL) photography was taken in patients with AMD with CNV to assess the presence of RNFL defects in the papillomacular bundle area. Patients with other ocular disorders or a history of previous intraocular surgery or laser treatment were excluded from this study. RESULTS: Eighty-five eyes in 65 patients were included, of which only one (1.2%) showed papillomacular bundle defects in association with CNV. CONCLUSIONS: From this study, the majority of the patients with AMD with CNV had no papillomacular bundle defect, which demonstrates that considerable amount of GCL is maintained in AMD.
Choroidal Neovascularization ; Ganglion Cysts ; Humans ; Macular Degeneration* ; Nerve Fibers* ; Neurons ; Photography* ; Retinal Ganglion Cells* ; Retinaldehyde*

PURPOSE: To evaluate diagnostic ability of macular ganglion cell complex (mGCC), macular ganglion cell inner plexiform layer (mGCIPL) measurements in glaucoma using swept source deep range imaging optical coherence tomography (DRI OCT-1, Topcon Co., Tokyo, Japan). METHODS: From August of 2014 to July of 2015, 109 eyes of 109 subjects were assessed for the average thickness and sectional thickness of both mGCC and mGCIPL to determine whether there exists any significant difference among advanced stage glaucoma group, early stage glaucoma group and normal group in Swept source OCT. Comparisons were also made between the above measurements and circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements in their diagnostic accuracy, sensitivity, and specificity. RESULTS: The diagnostic ability of mGCC based-mean thickness value (area under the curve [AUC] = 0.78/0.99) in detecting early stage glaucoma group as well as advanced stage group was not significantly different from that of cpRNFL thickness measurement. However, there was a significant difference in thickness between mGCIPL (AUC = 0.70) and cpRNFL in early stage glaucoma groups (p = 0.018). The sensitivities and specificities of mGCC were 0.95/0.97, and those of mGCIPL were 0.92/0.97, respectively. CONCLUSIONS: The two swept source OCT based methods measuring retinal ganglion cell layer thickness appeared to have a good diagnostic accuracy, high sensitivity and specificity in detecting glaucomatous eyes. Nevertheless, of the two methods, mGCC thickness measurement was more efficient in detecting early glaucomatous changes.
Ganglion Cysts* ; Glaucoma* ; Nerve Fibers ; Retinal Ganglion Cells ; Retinaldehyde ; Sensitivity and Specificity ; Tomography, Optical Coherence*

PURPOSE: To investigate circumpapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thicknesses as measured by optical coherence tomography in eyes with situs inversus of optic discs. METHODS: RNFL and macular GCIPL thicknesses were measured in eyes with situs inversus of optic discs without other ocular abnormalities (situs inversus group) and in age- and refractive error-matched healthy eyes (control group). RNFL thickness (global area, superior, nasal, inferior, and temporal quadrants) and GCIPL thickness (global area, superior-temporal, superior, superior-nasal, inferior-nasal, inferior, and inferior-temporal sectors and minimum) were compared between the groups. RESULTS: Nine eyes of 5 subjects with situs inversus of optic discs and 20 healthy eyes of 20 subjects (10 eyes for control groups A and B, respectively) were enrolled. No significant difference was found in superior or inferior quadrant RNFL thickness (p > 0.05); however, the situs inversus group showed a thicker RNFL in the nasal quadrant and a thinner RNFL in the temporal quadrant (p < 0.01). In macular GCIPL thickness, no significant difference was found in the superotemporal or inferiotemporal sector or for minimum thickness (p < 0.05); however, the situs inversus group showed thicker GCIPL in the global area, superior, superonasal, inferonasal, and inferior sectors than the control groups (p < 0.01). CONCLUSIONS: In eyes with situs inversus of optic discs, distribution of circumpapillary RNFL and macular GCIPL thickness were different from eyes without this condition. When assessing RNFL and macular GCIPL thicknesses in eyes with situs inversus of optic discs, caution is needed.
Ganglion Cysts* ; Nerve Fibers* ; Optic Disk ; Retinal Ganglion Cells ; Retinaldehyde* ; Situs Inversus* ; Tomography, Optical Coherence

Since the output of retina for visual stimulus is carried by neurons of very diverse functional properties, it is not adequate to use conventional single electrode for recording the retinal action potential. For this purpose, we used newly developed multichannel recording system for monitoring the simultaneous electrical activities of many neurons in a functioning piece of retina. Retinal action potentials are recorded with an extra-cellular planar array of 60 microelectrodes. In studying the collective activity of the ganglion cell population it is essential to recognize basic functional distinctions between individual neurons. Therefore, it is necessary to detect and to classify the action potential of each ganglion cell out of mixed signal. We programmed M-files with MATLAB for this sorting process. This processing is mandatory for further analysis, e.g. poststimulus time histogram (PSTH), auto-correlogram, and cross-correlogram. We established MATLAB based protocol for waveform classification and verified that this approach was effective as an initial spike sorting method.
Action Potentials ; Classification ; Electrodes ; Ganglion Cysts ; Microelectrodes ; Neurons ; Retina ; Retinal Ganglion Cells* ; Retinaldehyde*