Search

Purpose: To establish with negative electroretinogram (ERG) the clinical entity of eight patients with unilateral severe photophobia, essentially normal fundus, good visual acuity, and severe cone and rod dysfunction., Study Design: Multicenter retrospective observation case series., Methods: Comprehensive ophthalmologic examinations were performed, including best-corrected visual acuity (BCVA), full-field ERGs and multifocal ERGs (mfERGs), fundus photographs, and OCT. Systemic and genetic examinations were performed., Results: The mean (± SD) age at the onset was 60.0 ± 8.4 years, and the six patients noticed severe photophobia in the affected eye in spite of almost normal fundus appearance and good BCVA. The dark-adapted bright flash ERGs in the affected eye had relatively well-preserved a-waves and depressed b-waves, i.e., a negative ERG. Cone ERGs and both b- and d-waves of the photopic long-duration ERGs were almost undetectable. Rod ERGs were severely reduced; however, only two patients complained of night blindness. In five patients, the mfERGs were extinguished in the periphery but preserved in the central retina, resulting in good BCVA. Electrophysiological findings indicated a severe diffuse dysfunction of the inner retina affecting bipolar cells of both ON- and OFF-pathways, and in five patients there was a reduction in the thickness of the inner nuclear layer. In seven patients the retinal arteries were attenuated. Anti-retinal antibodies were detected in the serum of two patients. No genetic causes were found., Conclusions: The common features in the eight patients with unilateral negative ERGs suggest a new disease entity of unilateral acute inner retinal layer dysfunction. In most patients, the only subjective complain was photophobia.

Purpose: To report the findings in a 72-year-old man with neuronal intranuclear hyaline inclusion disease (NIHID) with the negative-type electroretinogram (ERG) and without night blindness., Methods: Standard ophthalmological examinations including the medical history, measurements of the best-corrected visual acuity and intraocular pressures, slit-lamp biomicroscopy, ophthalmoscopy, spectral-domain optical coherence tomography, fundus autofluorescence, and perimetry were performed. In addition, neurological and electrophysiological examinations were performed., Results: NIHID was confirmed by skin biopsy. The ophthalmologic examinations revealed sluggish pupillary reflexes without visual disturbances and retinal abnormalities. The amplitudes of the dark-adapted 0.01 ERG was absent, and light-adapted 3 ERG and light-adapted 30 Hz flicker ERG were reduced in amplitude and delayed in implicit time. The rod system was more severely affected than the cone system, indicating that NIHID is classified as one of rod-cone dysfunction syndrome. The dark-adapted 3 ERG consisted of a markedly reduced b-wave with larger a-wave (negative ERG), but the amplitude of a-wave was smaller than normal., Conclusions: Since the ophthalmoscopical findings and the subjective visual functions may be essentially normal, the characteristic ERG abnormalities can be an important findings in adult-onset NIHID without night blindness.

Intravitreal injections (IVI) have become a part of daily practice for a growing number of procedures. We evaluated the retinal function by recording intraoperative photopic electroretinograms (ERGs) before an injection (T1), just after the injection (T2), and after the aspiration of the anterior chamber fluid (T3) of 19 eyes of 19 patients (mean age 70.6 years; men = 11) who received an IVI of an anti-vascular endothelial growth factor. The mean amplitudes of the b-wave, photopic negative responses (PhNR), and oscillatory potentials (OPs) 1 and 2 at T2 were significantly smaller than that at T1, but no significant difference was observed between T3 and T1. The mean implicit times of the a-wave and OP1, 2, and 3 at T2 and the a-wave and the OP2 at T3 were significantly longer than that at T1. The mean intraocular pressure (IOP) at T2 (49.32 mm Hg) was significantly higher and the IOP at T3 (8.74 mm Hg) was significantly lower than that at T1 (21.05 mm Hg). The retinal function was reduced and the IOP elevated just after the IVI. The response of each ERG component was different suggesting a different sensitivity of each type of retinal neuron to IVI.

Purpose: We aimed to describe four cases with an acquired unilateral negative electroretinogram (ERG) and severe unilateral photophobia and assess the underlying pathology., Methods: We performed a retrospective chart view of the four cases by visiting two independent hospitals., Results: Over the last 10 years, a 65-year-old man, 71-year-old woman, 68-year-old man, and 73-year-old woman presented to the hospitals with unilateral photophobia. Symptom onset was relatively obvious in all the patients. Comprehensive examinations, including visual acuity and visual field assessment, optical coherence tomography, and fluorescein angiography, showed minimal change in the eye with photophobia. However, only in the affected eye, the mixed rod-cone response in full-field ERG showed a markedly electronegative pattern, namely the amplitude of a-wave was preserved and larger than that of b-wave, and the rod and cone responses were very low. In fact, the cone responses were almost absent in all four patients. ERG findings indicate dysfunction of both rod and cone visual pathways, and the preserved a-wave in the mixed rod-cone ERG suggests that the disturbance of the rod visual pathway exists in post-photoreceptors. Moreover, although multifocal ERG showed a very low amplitude in the entire area, the preservation of the responses was detected to some extent only in the center. These symptoms and examination findings remained unchanged for more than 4 years., Conclusions: Four patients with acquired unilateral negative ERG associated with severe photophobia showed similar clinical findings. To our knowledge, no known disorders can explain these conditions.

Purpose: To describe a new technique to record focal macular electroretinograms (FMERGs) during vitrectomy to assess macular function., Methods: Intraoperative FMERGs (iFMERGs) were recorded in ten patients (10 eyes) who undergo vitrectomy. iFMERGs were elicited by focal macular stimulation. The stimulus light was directed to the macular area through a 25 gauge (25G) glass fiber optic bundle. Background light was delivered through a dual chandelier-type light fiber probe. Focal macular responses elicited with combinations of stimulus and background luminances were analyzed., Results: A stimulus luminance that was approximately 1.75 log units brighter than the background light was able to elicit focal macular responses that were not contaminated by stray light responses. Thus, a stimulus luminance of 160 cd/m2 delivered on a background of 3 cd/m2 elicited iFMEGs from only the stimulated area. This combination of stimulus and background luminances did not elicit a response when the stimulus was projected onto the optic nerve head. The iFMERGs elicited by a 10° stimulus with a duration of 100 ms and an interstimulus interval of 150 ms consisted of an a-, b-, and d-waves, the oscillatory potentials, and the photopic negative response (PhNR)., Conclusions: Focal ERGs with all components can be recorded from the macula and other retinal areas during vitreous surgery. This new technique will allow surgeons to assess the function of focal areas of the retina intraoperatively.

Background: Unilateral retinitis pigmentosa is a retinal dystrophy affecting only one eye, the fellow eye being affected neither functionally nor in fundus appearance. There are relatively few cases of unilateral retinitis pigmentosa being followed for more than 5 years., Case: An 18-year-old woman complaining of blurred vision of left eye was found to have left visual field concentric contraction. Because the right eye was unaffected electrofunctionally and in fundus appearance, there was a suspicion of unilateral retinitis pigmentosa. We tracked her for 8 years and, because the right eye remained unaffected, we diagnosed unilateral retinitis pigmentosa of left eye., Conclusion: We report a case of unilateral retinitis pigmentosa. It is reported that the healthy fellow eye of patients with unilateral retinitis pigmentosa developed bilateral retinitis pigmentosa after 10 years, consequently, this case needs further follow-up.

Background: To determine whether the focal macular electroretinograms (FMERGs) are affected by the angle of incidence of the stimulating light on the retina, i.e., the Stiles-Crawford effect (SCE)., Methods: FMERGs were elicited by focal stimulation of the macula in three light-adapted macaque monkeys. The incidence of the light on the retina was varied from 0 to ±11.7°. The effects of the incidence and wavelengths of the stimulus on the SCE were determined., Results: The amplitudes of the FMERG components were largest when the stimulus beam entered the eye on the visual axis and passed through the center of the pupil. The amplitudes gradually decreased as the stimulus beam passed through the pupil more eccentrically and fell on the retina more obliquely. All components of the FMERGs were decreased with the decrease least for the amplitude of the d-wave., Conclusions: The decrease in the amplitudes of the FMERGs as the angle of incidence of the stimulus beam on the retina increases demonstrates that the SCE can be detected in adult macaque monkeys. This objective method of assessing the SCE suggests that this technique can be used to assess the alignment of cones in humans with different types of macular diseases.

This document presents recommendations and guidelines for the use of visual electrophysiological testing in the clinical assessment of visual pathway function., (2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV), presents an updated and revised ISCEV Standard for clinical electroretinography (ERG). The parameters for flash stimulation and background adaptation have been tightened, and responses renamed to indicate the flash strength (in cd x s x m(-2)). The ISCEV Standard specifies five responses: (1) Dark-adapted 0.01 ERG (rod response); (2) Dark-adapted 3.0 ERG (combined rod-cone response); (3) Dark-adapted 3.0 oscillatory potentials; (4) Light-adapted 3.0 ERG (cone response); (5) Light-adapted 3.0 flicker (30 Hz flicker). An additional Dark-adapted 10.0 ERG or Dark-adapted 30.0 ERG response is recommended.

Purpose: To study the functional changes in the macula of the retina in the early stage of retinitis pigmentosa (RP), by analyzing each component of the focal macular electroretinogram (fmERG)., Methods: fmERGs were recorded from 39 patients with RP with normal visual acuity (>1.0) under direct fundus observation using a modified infrared fundus camera and 5 degrees , 10 degrees , and 15 degrees stimulus spots. The amplitudes and implicit times of the a-wave, b-wave, and oscillatory potentials (OPs) in the patients with RP were compared to those from 30 age-similar normal control subjects., Results: The amplitudes of the different components of the fmERGs in patients with RP ranged from severely reduced to normal. The degree of amplitude reduction increased as the size of the stimulus spot increased in the patients with RP. The relative amplitudes of the OPs (67% of the mean in normal subjects) were better preserved than that of the b-wave (46%) and the a-wave (39%) in a 10 degrees spot in the patients with RP., Conclusions: The relative preservation of the OPs in the patients with RP could be due to either the buffering effect of the large receptive fields of the OP generators or to the retinal remodeling after the progressive loss of photoreceptors. Recordings of each component of fmERG can provide important information on the different layers of the central retina in RP eyes and can add to the understanding of the pathophysiology of RP.

Purpose: Intrinsic signal imaging is a newly developed technique that can map the neural activity of tissues noninvasively. It has been used to map the functional organization of the retina by recording flash-induced light reflectance changes in the cone and rod photoreceptors. The purpose of this study was to investigate the properties of the intrinsic signals in the monkey's retina. To accomplish this, the intrinsic signals and the electroretinograms (ERGs) evoked by the same stimuli were measured under different recording conditions., Methods: The fundus of macaque monkeys was observed with infrared light and recorded with a charge-coupled device (CCD) camera. The intrinsic signals were measured as retinal light reflectance changes induced by diffuse or focal flash stimuli. ERGs were recorded under the same stimulating conditions. The reflectance changes induced by different flash intensities, flash intervals, and background luminance were compared., Results: The intrinsic signals were categorized into different groups based on the location in the fundus. Fast signals (peak: approximately 100 ms) were recorded from the posterior retina including the fovea, and slow signals (peak: 5.0-6.0 seconds) were recorded from the optic disc and nonfoveal posterior retina. The threshold of the slow signal changes was comparable to that of the ERG b-wave, and the thresholds of the fast signals were higher than that of the ERG a- and b-waves., Conclusions: The retinal intrinsic signals are composed of several components with different response properties and different sources. This recording technique may be useful for mapping the retinal function in eyes with various disorders.

Purpose: To investigate feasibility and recording conditions of recording rod on and off responses in electroretinograms (ERG) and multifocal electroretinograms (mf-ERG), and observe character and influence factors of these responses., Methods: ERG responses were recorded using the rectangle stimulus, sawtooth rapid-on and rapid-off stimulus in normal subjects after dark adaptation. Flash frequency and flash intensities varied to obtain appropriate recording conditions for clinical use. Mf-ERG responses were recorded in using simulated rectangle stimulus, saw tooth rapid-on and rapid-off stimulus., Results: A large positive wave was found in ERG of rectangle stimulus and rapid-on stimulus. Increasing flash frequency decreased response amplitudes, however, the latency time changed little. A small negative wave with 80 ms latency time was found in ERG of rapid-off stimulus, and a very small positive wave with 75 ms latency time was found in the downhill of the negative wave. Increasing flash frequency increased latency time of the negative wave, but decreased the amplitude of the small positive wave. Oscillatory wave-like waves were found in the responses when flash frequency increased to 3 Hz. A large negative wave following a positive wave was found in mf-ERG of simulated rapid-off stimulus, which was difference from the wave of simulated rectangle stimulus and rapid-on stimulus., Conclusions: Rod on and off responses of ERG can be recorded with sawtooth rapid-on and rapid-off stimulus. There is a small positive wave in downhill of negative wave in rod off response. Rod on response of mf-ERG can be recorded with simulated rapid-on stimulus. The flash frequency of 0.5-1 Hz and small flash intensity were suggested to appropriate conditions for recording rod on and off responses in ERG. The simulated rapid-on, sawtooth rapid-on and rapid-off stimulus can be used to investigate retinal disease.

Bietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessive chorioretinal dystrophy characterized by progressive night blindness, tiny, yellowish, glistening retinal crystals, choroidal sclerosis, and crystalline deposits in the peripheral cornea. Recent studies have demonstrated that the CYP4V2 gene which encodes a CYP450 family protein is the causative gene of the disease. We have identified a homozygous mutation in the CYP4V2 gene in 8 separate Japanese patients with BCD and conclude that mutations in the CYP4V2 gene are the major cause of BCD. The IVS6-8_c.810del/insGC mutation is found at a higher frequency in the Asian populations suggesting a founder effect.

Purpose: To evaluate the short- and long-term changes of focal macular electroretinograms (fmERGs) after macular translocation with 360 degrees retinotomy., Methods: This was a retrospective study. fmERGs were recorded in 19 eyes of 19 consecutive patients who underwent macular translocation with 360 degrees retinotomy for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD; 17 eyes) or polypoidal choroidal vasculopathy (2 eyes). The changes in the fmERGs, recorded before, shortly after (6-12 months; mean 8.3 months), and more than 18 months (18-30 months; mean 22.4 months) after surgery from 12 eyes, were analyzed. A 15 degrees stimulus centered on the fovea was used to elicit the fmERGs., Results: The mean logarithm of minimum angle of resolution (logMAR) was 1.06 +/- 0.07 (20/230) before surgery, 0.78 +/- 0.08 (20/121) early after surgery (n = 19), and 0.64 +/- 0.07 (20/87) late after surgery (n = 12). These improvements in visual acuity were significant (P = 0.0074, P = 0.0050, respectively). Before surgery, the amplitudes of all components of the fmERGs were markedly reduced in all eyes. The mean b-wave amplitude in 17 AMD eyes recorded early after surgery was significantly larger (P = 0.0262), and the mean a-wave amplitude was also increased but not significantly (P = 0.1180). The mean amplitudes of the a- and b-waves in 10 AMD eyes recorded after 18 months were significantly larger than those before the surgery (P = 0.0218, and P = 0.0284). The mean implicit time of the b-wave in 17 AMD eyes decreased early after surgery, and a further decrease was detected at the later testing time., Conclusions: These results indicate that macular function is partially recoverable after macular translocation in some patients.

Purpose: To study local retinal cone function in patients with X-linked retinoschisis (XLRS) by multifocal ERGs (mfERGs)., Methods: mfERGs were recorded from seven eyes of seven patients with XLRS (mean age +/- SD, 22.1 +/- 3.2 years; range, 18 to 25 years). Five eyes had microcystic changes in the macula and two eyes had nonspecific macular degeneration. Two eyes had peripheral retinoschisis, and some of the stimuli fell on this area. The stimulus array consisted of 103 hexagons and the total recording time was set at approximately 4 minutes. The amplitudes and implicit times of both focal and summed responses for the first- and second-order kernels were analyzed., Results: The amplitudes of the first-order kernel were markedly reduced in the central retina in all eyes. A large variation was observed in the amplitudes outside the fovea. The amplitudes of the focal cone ERGs at the peripheral retinoschisis did not differ from those recorded from adjacent retinal loci without the retinoschisis. The implicit times of the first-order kernel were significantly delayed, and the amplitudes of the second-order kernels were more affected than the first-order kernels across the whole field in all XLRS eyes., Conclusions: The cone-mediated retinal responses were more impaired in the central than peripheral retina in eyes with XLRS. Delayed implicit times of the first-order kernel and reduced second-order kernel across the whole testing field in all XLRS eyes suggest that there is widespread cone-system dysfunction in XLRS.

The aim of this study was to analyze the RDH5 gene in patients with fundus albipunctatus with and without macular dystrophy, and correlate the identified mutations with the electrophysiological results. Twenty-one patients from 19 unrelated Japanese families with fundus albipunctatus were examined. Ten unrelated patients had macular dystrophy. In 18 patients, either a homozygous or a compound heterozygous mutation in the RDH5 gene was identified. The bright-flash, mixed rod-cone ERG had a negative configuration with reduced a-wave amplitudes after a short period of dark-adaptation (20 or 30 min). After a prolonged dark-adaptation period (2 or 3 h), the waveform attained normal amplitudes in patients without macular dystrophy but the a-waves were still subnormal in patients with macular dystrophy. The photopic ERG responses were significantly reduced in patients with macular dystrophy, indicating that they also had cone dystrophy. The photopic ERGs were reduced in only some of the patients without macular dystrophy. In patients without macular dystrophy, the scotopic b-wave amplitudes were nonrecordable or significantly reduced after a short dark-adaptation period but then improved to normal levels. However, they did not fully recover in some patients with macular dystrophy. Three patients with macular dystrophy in whom a RDH5 gene mutation could not be detected by our routine method had atypical ERG responses. We conclude that RDH5 gene mutations cause a progressive cone dystrophy or macular dystrophy as well as night blindness. The clinical phenotype including electrophysiological responses varied among patients with the RDH5 gene mutations.

Purpose: To report reduced oscillatory potentials (OPs) in the full-field electroretinogram (ERG) of eyes with aphakic or pseudophakic cystoid macular edema (CME)., Design: Observational case series., Methods: Bright white flash full-field ERGs were recorded from 19 eyes of 19 patients (ages, 53-84 years) with aphakic or pseudophakic CME. Seven of the cases had uncomplicated phacoemulsification (PE) with implantation of a posterior chamber intraocular lens (PC-IOL) and 6 had posterior capsular rupture during phacoemulsification and aspiration with implantation of a PC-IOL. Four additional patients had uncomplicated intracapsular cataract extraction (ICCE), and 2 had secondary anterior chamber intraocular lens after ICCE. Their fellow eyes without CME served as controls. Cystoid macular edema was diagnosed as clinically significant by slit-lamp examination and by fluorescein angiography. The grading for severity of CME was based on the fluorescein angiography. The visual acuity ranged from 20/200 to 20/16., Results: There were no significant differences in the mean amplitudes and implicit times of the a-waves and b-waves between the affected eyes and the fellow eyes. The mean summed amplitude of the OPs was significantly reduced in the affected eyes (P =.0003, Wilcoxon signed rank test). This decrease was strongly correlated with visual acuity (r =.779, P <.0001). The mean implicit time of the first OP was significantly delayed in the affected eyes (P =.0089, Wilcoxon signed rank test)., Conclusions: Because the peripheral retina contributes more significantly to full-field ERGs than the macula, the reduced OP amplitudes of the full-field ERGs in eyes with aphakic or pseudophakic CME suggest a functional impairment not only in the macula but also throughout the retina.

Purpose: To evaluate the changes in focal macular electroretinograms (fmERGs) after surgical removal of choroidal neovascular (CNV) lesions., Methods: Fourteen patients (14 eyes) with subfoveal or juxtafoveal CNV associated with age-related macular degeneration and 1 patient with idiopathic CNV underwent vitrectomy and removal of the lesions. fmERGs elicited by a 15 degree stimulus were recorded before and 3 months after surgery. Optical coherence tomography (OCT) was performed to measure the foveal and parafoveal thickness before and 3 months after surgery., Results: Preoperative fmERGs were markedly reduced in all eyes. The mean amplitude of the b-wave in 15 eyes recorded 3 months after surgery increased significantly (P = 0.0022, Wilcoxon signed rank test). In all eyes except two with nearly nonrecordable a- and b- waves, the mean b-wave-to-a-wave ratio after surgery increased significantly in all eyes (P = 0.0330, Wilcoxon signed rank test). The percentage increase in the b-wave amplitude correlated significantly with the percentage decrease in the mean parafoveal retinal thickness (r = 0.688, P = 0.0076)., Conclusions: The decreased macular ERGs were partially recoverable in the early postoperative period. The decreased retinal edema after surgery may have contributed to this recovery.

Purpose: One of the methods used in macular translocation (MT) surgery for subfoveal neovascularization is to create a temporary total retinal detachment followed by a 360 degrees retinotomy. The whole retina is then shifted from the original surface of the retinal pigment epithelium (RPE), resulting in an unusual retina and RPE complex. The purpose of this study was to assess retinal function after MT surgery., Methods: Full-field electroretinograms (ERGs) were recorded before and 4 to 8 months (mean, 5.4 months) after MT surgery with a 360 degrees retinotomy in 15 consecutive patients with age-related macular degeneration (10 eyes), high myopia (4 eyes), and polypoidal choroidal vasculopathy (1 eye). Their ages ranged from 57 to 74 years. The angle of rotation of the retina ranged from 18 degrees to 45 degrees (mean +/- SE, 30 +/- 2 degrees). In addition to the recording of the standard rod and mixed rod-cone ERGs after 30 minutes of dark adaptation, the cone single flash and 30-Hz flicker ERGs were recorded immediately after a light-adapting background was turned on (LA(0)) and also after 10 minutes of light adaptation (LA(10))., Results: The mean amplitude of the full-field ERGs was reduced after surgery by 44% for the rod response, by 24% for the mixed rod-cone b-wave, by 12% and 35% for the cone single-flash b-wave at LA(0) and 30-Hz flicker ERGs at LA(0), respectively. The mean implicit times were delayed by 8 msec for the rod response, by 2 msec for the mixed rod-cone oscillatory potential (OP1), by 4 msec for the cone single-flash b-wave at LA(0), and by 6 msec for the 30-Hz flicker at LA(0)., Conclusions: These results demonstrated a functional alteration in both the rod and cone components of the ERGs for the entire retina after MT surgery.

Purpose: To determine whether single flash electroretinograms can assist in the diagnosis of eyes with endophthalmitis after intraocular lens implantation., Methods: Sixteen eyes with postoperative endophthalmitis treated with vitrectomy or intraocular lens removal were studied. The preoperative electroretinogram findings, duration until the onset of endophthalmitis, culture results, and postoperative visual acuity were analyzed., Results: Four eyes with a b-wave/a-wave (b/a) ratio less than 1.0 and early onset of endophthalmitis within 1 week had worse postoperative visual acuity (no light perception to 20/200) than the other 12 eyes (20/100 to 20/15) (P =.0035). Pseudomonas aeruginosa and Enterococcus faecalis were cultured in these 4 eyes., Conclusion: The combination of a b/a ratio less than 1.0 and early onset of endophthalmitis may indicate poor prognosis in a patient with postoperative endophthalmitis.

Purpose: To study the multifocal electroretinogram (mfERG) in patients with the complete type of congenital stationary night blindness (cCSNB), which is thought to be due to a defect in neurotransmission from the photoreceptors to the ON-bipolar cells., Methods: mfERGs were recorded with the VERIS recording system from four patients with cCSNB, none of whom had nystagmus. The stimulus array consisted of 61 hexagons, and the total recording time was approximately 4 minutes. The amplitudes and implicit times of the first- and second-order kernels of the local responses were compared with those from 20 myopic controls. Waveforms of the summed response from all locations were also compared between the two groups., Results: The first-order kernels of the mfERGs of cCSNB patients had normal amplitudes but delayed implicit times for nearly the whole field tested. The second-order kernel was severely attenuated in amplitude in cCSNB patients. The ratios of the second- to first-order kernel amplitudes were significantly reduced in cCSNB and clearly separated the cCSNB group from the control group without any overlap of the values., Conclusions: The second-order kernel, which is involved in adaptative mechanism of the retina to repeated flashes, is selectively reduced in cCSNB. The delay of the implicit times of the first-order kernel in patients with cCSNB may be related to the severe amplitude reduction of the second-order kernel.

Purpose: The removal of the internal limiting membrane (ILM) for traction maculopathy has recently been advocated. However, it is generally believed that the ILM plays an important role in retinal function, because it is the basal lamina of the Müller cells that are involved in the generation of the electroretinogram (ERG) b-wave. To date, there has been no objective assessment of retinal function on removing the ILM. In this study, the changes of each component of the focal macular electroretinograms (FMERGs) were investigated in eyes before and after the ILM was removed in the macular area during surgery for idiopathic macular holes (IMHs)., Methods: FMERGs were elicited by a 15 degrees stimulus centered on the fovea and monitored by an infrared fundus camera. FMERGs were recorded from 49 eyes of 48 patients with IMHs before and 6 weeks after anatomically successful macular hole surgery. Whether an eye had or did not have the ILM removed was randomly determined. The ILM was removed in 30 eyes (ILM-off group) and was not removed in 19 eyes (ILM-on group). Six months after surgery, the same examination was performed in 27 eyes of the ILM-off group and in 15 eyes of the ILM-on group. The amplitudes and implicit times of the a- and b-waves and the mean amplitudes and implicit times of the first three oscillatory potentials (OP1 to OP3) were compared before and after surgery within and between the groups., Results: Visual acuity increased significantly after surgery in both groups. In the ILM-on group, the amplitude of the a- and b-waves and the OPs increased significantly 6 months after surgery (P: = 0.0093, P: = 0.0019, P: = 0.0024, respectively, paired t-test). In the ILM-off group, the a-wave amplitude and mean OP amplitudes were significantly larger 6 months after surgery (P: = 0.0077, P: = 0.0030, respectively, paired t-test). The b-wave amplitude, however, did not change significantly. The percentage increase in the b-wave amplitude 6 months after surgery was significantly higher in the ILM-on group (44.0%) than in the ILM-off group (15.0%; P: = 0.037, t-test)., Conclusions: The removal of the ILM had no adverse effect on visual acuity. However, the selective delay of recovery of the FMERG b-wave 6 months after surgery suggests an alteration of retinal physiology in the macular region.

We determined the clinical usefulness of a new contact lens electrode with built-in, white light-emitting diodes (LEDs) for full-field electroretinograms (ERGs). Three, high-brightness white LEDs were incorporated into a contact lens electrode and served as the source for the stimulus and the background. The stimulus intensity, stimulus duration and background illumination were regulated by a small LED control device. Maximum stimulus and background intensities were 3.9 and 3.6 log cd/m2, respectively. We successfully recorded intensity-response series for scotopic and photopic ERGs. We also recorded a duration-series for photopic ERGs, and ERGs that were comparable to the ISCEV standardized ERGs. The compactness and ease of using this system suggest that it will be clinically useful under different conditions.

The pattern electroretinogram (PERG) is a retinal response evoked by viewing an alternating checkerboard or grating. It receives clinical and research attention because it can provide information about inner retinal cells and the macula. However, clinicians may have trouble choosing between different techniques for recording the PERG that have been described in the literature. The International Society for Clinical Electrophysiology of Vision has prepared a standard for a basic PERG recording procedure to aid new users in obtaining reliable responses and to encourage more uniformity among existing users.

Purpose: Occult macular dystrophy (OMD) is an unusual macular dystrophy presenting with an essentially normal fundus and fluorescein angiography but with progressive central visual loss. The authors studied the function of local retinal areas in the posterior pole of patients with OMD using multifocal electroretinograms (ERGs)., Methods: Multifocal ERGs were recorded using the Visual Evoked Response Imaging System with 61 hexagonal elements within a visual field of 30 degrees radius from 8 OMD patients and 20 age-matched, normal subjects. The amplitudes and implicit times of the patients and normal control subjects were compared at the various retinal eccentricities. RESULTs. The amplitudes of the multifocal ERGs in the OMD patients were markedly reduced in the central 7 degrees of the fovea. The difference of the ERG amplitudes between OMD and normal subjects became smaller toward the peripheral retina. Most OMD patients had slight but significantly delayed implicit times across the whole testing field, and the differences between the OMD and the normal subjects did not change with retinal eccentricity., Conclusions: Our results for multifocal ERG amplitudes support the idea that OMD patients have localized retinal dysfunction distal to the ganglion cells in the central retina. The delayed implicit times across the whole test field suggest that the retinal dysfunction has a broader boundary than expected by ERG amplitudes and psychophysical perimetric results.

There is evidence that recording the photopic ON- and OFF-responses with long-duration stimuli is useful for determining the contribution of the cone ON- and OFF-pathways to the primate photopic electroretinogram (ERG). In this study, the optimal conditions for recording multifocal ON-OFF responses are described, and the technique is applied to normal subjects and two patients with unusual retinal diseases. The results from the normal subjects demonstrated that there were topographical variations of the photopic ERG waveform: when responses were normalized to the ON-response (b-wave) amplitude, the OFF-response (d-wave) amplitude increased with increasing eccentricity. The changes in the waveform in two patients suggested relatively greater defects of the hyperpolarizing or depolarizing bipolar cells. We conclude that the multifocal ERG technique with long-duration stimuli can be a useful tool to assess the function of local cone ON- and OFF-pathways in normal and diseased retinas.

Purpose: The b-wave of the human photopic electroretinogram (ERG) elicited by a short-flash increases in amplitude with increasing stimulus intensities at lower stimulus levels, but then decreases at higher stimulus intensities. The purpose of the present study was to explore this phenomenon in more detail, using short- and long-flash stimuli., Methods: The intensity-response functions of the b-wave elicited by short- and long-flashes were compared from threshold to higher stimulus intensities in 5 normal subjects. Short- and long-flash ERGs were elicited under rod-saturating background levels using white light-emitting diodes built into a contact lens electrode., Results: Whereas the amplitude of the short-flash b-wave decreased at higher intensities, the amplitude of the long-flash ERG b-wave did not decrease but plateaued. The long-flash ERG d-wave or OFF-response decreased at higher stimulus levels as did the short-flash elicited b-wave., Conclusions: Because it is widely accepted that the b-wave and the OFF-response d-wave interact to produce a single positive response, our results suggest that the decrease in the b-wave amplitude at high stimulus intensity is caused by the decrease of the d-wave at the higher stimulus intensities.

Purpose: To determine using the multifocal ERG technique whether there are any regional differences in the increase in the amplitude of cone electroretinograms (ERGs) during light adaptation., Methods: Multifocal ERGs were recorded with the Visual Evoked Response Imaging System from five normal subjects. Thirty-seven hexagonal stimulus elements and a recording time of 60 seconds were used. After 20 minutes of dark adaptation, multifocal ERGs were repeatedly recorded every 2 minutes over a period of 16 minutes. The amplitudes of the multifocal ERGs at different eccentricities were compared during the 16 minutes of light adaptation., Results: During the 16 minutes of light adaptation, the summed responses of the multifocal ERGs increased in amplitude an average of 36% and 47% for the negative and positive components, respectively. The magnitude of increase was minimal in the central retina at 22% and was significantly larger in the peripheral retina at 58%. The implicit time was slightly increased (<4%) with light adaptation, but there were no regional differences., Conclusions: The results demonstrated that there are topographic variations in the amplitude increase of cone ERGs during light adaptation. This topographic variation indicates that the mechanism for the increase must be based on known regional differences in the retina.

Purpose: To study the functional state of the retina beneath an epimacular membrane by means of focal macular electroretinography., Methods: Focal macular electroretinograms of 30 consecutive patients (age 25 to 75 years) with unilateral idiopathic epimacular membrane were recorded prospectively. The amplitudes and implicit times of the a and b waves and the oscillatory potentials (O1, O2, O3) recorded from the eye with idiopathic epimacular membrane were compared with those of the normal fellow eye., Results: There was a statistically significant reduction in the amplitude of the a wave (P < .001), the b wave (P < .001), and the oscillatory potentials (O1 + O2 + O3; P < .001) of the affected eyes. The reduction of the b-wave amplitude was significantly greater than that of the a wave, resulting in a lower b/a wave ratio (P = .003) in the affected eyes. The reduction in the amplitude of the oscillatory potentials was significantly greater than that of the other two components (P < .001). The implicit times were significantly prolonged for the a wave (P < .001), the b wave (P = .004), and 03 (P < .001). There was a significant correlation between relative b-wave amplitude (affected/normal fellow eye) and the visual acuity (r = -0.50, P = .007). These findings were similar to those we reported for eyes with aphakic cystoid macular edema., Conclusions: The focal macular electroretinograms in eyes with epimacular membrane disclosed abnormalities that were similar to those of eyes with cystoid macular edema. This suggests that the epimacular membrane probably induced damage to the neurons in the inner retinal layers. Dysfunction of these neurons is one possible cause of visual impairment in this disease.

Objective: To study the origin of the different components of the electroretinogram (ERG) elicited by a random binary m-sequence stimulus., Methods: Electroretinograms were recorded from pigmented rabbits before and after the injection of glutamate analogues (2-amino-4-phosphono-butyric acid [APB; DL form] and cis-2,3-piperidine-dicarboxylic acid [PDA]) and inhibitory neurotransmitters (glycine and gamma-aminobutyric acid [GABA]) to abolish the contribution of different cell types to the ERG. Two types of stimuli were used: conventional full-field stimulation with short- and long-duration flashes and a random binary m-sequence of flashes designed to mimic the pseudorandom binary m-sequence stimulation used in the multifocal ERG technique., Results: The effects of APB and PDA on the first-order kernel of the random ERGs were similar to those on the photopic short-flash ERG. Glycine and GABA minimized the oscillatory potentials (OPs) of the photopic ERGs, and also reduced the amplitude of the positive wave of the first-order kernel slightly but caused a large reduction in the amplitude of the second-order kernel., Conclusions: The data suggest that the ON and OFF bipolar cells contribute significantly to the photopic short-flash ERG, as previously shown, and to the first-order kernel of the responses elicited by the pseudorandom binary sequence stimuli. The second-order kernel and the OPs receive a strong contribution from the cells of the inner retinal layers.

Using a light-emitting diode (LED) built-in contact lens electrode, we studied the effect of age on short-wavelength sensitive cone electroretinograms (S-cone ERG) and long- and middle-wavelength sensitive cone ERGs (LM-cone ERG). We recorded ERGs in 31 pseudophakic subjects to avoid the effect of yellowing in the human crystalline lens. The intensities of our stimuli were on the asymptote of the intensity-response curve. Linear regression analysis against age was carried out on the S-cone ERG b-wave, and the LM-cone ERG a-, b-, and d-waves. We found significant age-dependent reduction in the amplitude of the S-cone ERG b-wave, and the LM-cone ERG a- and d-waves, significant prolongation in the peak time of the S-cone b-wave and the LM-cone ERG b-wave, significant increase in the b/a ratio of the LM-cone ERG, but no significant age correlation between the LM-cone ERG a-wave and the amplitude of the b-wave. Our results provide evidence that age-related changes in S- and LM-cone systems begin in early adulthood in the human eye. A significant increase in the b/a ratio suggests that off-bipolar cells are more vulnerable to aging than on-bipolar cells.

Purpose: To record the on and off responses of the multifocal photopic electroretinogram (ERG) from the human retina and to explore how each ERG component (a-, b-, and d-waves) changes at different retinal eccentricities., Methods: Multifocal ERGs were recorded with the visual evoked response imaging system. Sixty-one densely packed stimulus elements were square wave-modulated between stimulus on and stimulus off, according to a binary m-sequence at a rate of 4.7 Hz under a constant background illumination. The ERGs were recorded with a bipolar Burian-Allen bipolar contact lens electrode from five normal subjects. Response densities (amplitude per retinal area) were calculated for five different eccentric rings., Results: The response densities for all components (a-, b-, and d-waves) decreased with increasing retinal eccentricities. The ratio of the d-wave to b-wave amplitudes was minimal in the central retina and increased toward the periphery. The ratio of a-wave to b-wave amplitudes also increased toward the peripheral retina., Conclusions: These results demonstrate that the on and off responses of the human cone ERGs have different spatial distributions across the human retina, and they suggest a change in the photopic retinal circuitry with increasing retinal eccentricities.

Background: We previously reported a new system of electroretinographic monitoring of the retinal function during vitrectomy in human eyes, and found that lowering the intravitreal temperature by applying an infusion solution kept at room temperature (used routinely for vitrectomy throughout the world) can alter the electroretinogram (ERG). This time we attempted to study the effect upon the ERG of replacing the intraocular medium and acutely elevating the intraocular pressure during vitrectomy., Methods: Using a special contact lens with a built-in light-emitting diode light source, 30-Hz flicker ERG was quickly recorded under aseptic conditions., Results: Acute, reversible reduction in amplitude was observed upon replacing the intraocular medium with air or silicon oil and during periods of acutely elevated intraocular pressure. Infusions of gentamicin or miconazole did not affect the ERG when intravitreal temperature and intraocular pressure were constant., Conclusion: The ERG monitor can reveal changes of the retinal function during vitrectomy, particularly when the infusion temperature, intraocular medium and intraocular pressure are kept constant.

We studied the effect of age on short-wavelength sensitive cone electroretinogram (S-cone ERG) and long-and middle-wavelength sensitive cone ERG (LM-cone ERG) using a contact lens electrode with a built-in light-emitting diode. We recorded ERGs in 31 pseudophakic subjects to avoid the effect of yellowing in human crystalline lens. The intensities of our stimuli were on the asymptote of the intensity-response curve. We performed linear regression analysis against age on the S-cone ERG b-wave (S-b), and the LM-cone ERG a-, b- and d-waves (LM-a, LM-b, LM-d). We found significant age-dependent reduction in the amplitude of S-b, LM-a, and LM-d, significant prolongation in the peak time of LM-b and LM-d, and significant increase in the b/a ratio of the LM-cone ERG, but no significant age correlation between the peak time of S-b and LM-a and the amplitude of the b-wave. Our results provide evidence that age-related changes in S- and LM-cone systems begin in the twenties in humans. Furthermore, a significant increase of the b/a ratio suggests that off-bipolar cells are more vulnerable to aging than on-bipolar cells.

Focal macular electroretinograms (MERGs) were recorded with a fundus monitor through an infrared television fundus camera in 112 eyes of 112 normal subjects (68 males, 44 females), using three stimulus spots 5 degrees, 10 degrees, and 15 degrees in diameter. The amplitude and the implicit time of the a-wave, h-wave, and oscillatory potentials (OPs), and the ratio of amplitude of the b-wave to the a-wave (b/a ratio) at each stimulus spot were compared in terms of aging and sex. The amplitude of all components decreased significantly (p < 0.01-0.05) after the fifth decade, and there was a tendency for OPs to decrease more than the a-wave and b-wave. There was no significant effect of age on the h/a ratio and the implicit time of each component. The ratio of increase of amplitude to the enlargement of stimulus spot showed no significant changes with age. There was no significant difference in each component in terms of amplitude and implicit time with sex. The decrease of amplitude of all components after the fifth decade suggests aging of the macular cones. The tendency toward decreasing OPs also suggests aging of the inner retina in the macular region. The proportional changes of amplitude recorded with three different sizes of stimulus spots indicate that there is no significant effect of aging on the fovea, parafovea, or perifovea.

Purpose: To record multifocal electroretinograms (ERGs) with simultaneous fundus monitoring., Methods: An infrared television fundus camera was used to monitor the fundus. A tightly packed array of 19 yellow light-emitting diodes (LEDs) was used as the stimulus source and LEDs were alternated between on and off according to a binary m-sequence at a rate of 75 Hz. The stimulus array subtended approximately 25 degrees of the visual angle. Multifocal ERGs were recorded with a Burian-Allen bipolar contact lens electrode from two normal subjects and a patient with macular dystrophy., Results: When the center of the stimulus was positioned on the fovea, the amplitude of the response was largest at the fovea and decreased toward the peripheral retina; the response pattern corresponded to the spatial distribution of cone cells. When the center of the stimulus was positioned on the optic disc, the response at the optic disc was undetectable. A reliable multifocal ERG was obtained from a patient with macular dystrophy., Conclusions: This system made it possible to monitor the stimulus on the fundus and to adjust the stimulus to the correct retinal locations with exact focusing. The authors' findings indicate that this method especially can be useful in patients with poor fixation. In addition, the authors' results suggests that the stray light effect in the multifocal stimulus system is minimal if any.

Multifocal electroretinograms (ERG) were recorded from 21 normal eyes to investigate the spatial distribution and inter-individual variation of local cone responses. To compensate for the effect of refractive lenses, test distances were adjusted to obtain a constant magnification on the retina. Significant nasal-temporal asymmetry was observed near the fovea with higher response densities in the temporal retina along the horizontal meridian. No significant supero-inferior asymmetry was observed along the vertical meridian. The average coefficient variation (standard deviation/average) of retinal response density for all areas was 0.35. In the clinical application of the multifocal ERG these results must be taken into consideration.

Purpose: To develop a contact lens electrode with a built-in blue light-emitting diode (LED) to record the electroretinogram from short-wave sensitive-cone (S-cone) electroretinogram (ERG) in humans., Methods: The ERG was recorded using the blue LED (450 nm) built-in electrode under a yellow background illumination from a slide projector in five normal subjects, a patient with blue cone monochromatism, and a patient with fundus albipunctatus. For comparison, the ERG was also recorded using a yellow LED (566 nm) built-in electrode under the same background illumination in the normal subjects., Results: The amplitude and the peak time of the b-wave recorded with 3-Hz blue stimuli were 5.1 to 12.4 microV and 63 to 68 msec, respectively in normal subjects, 7.3 microV and 65 msec in the patient with blue cone monochromatism, and 11.4 microV and 65 msec in the patient with fundus albipunctatus. Normal subjects responded to neither 30-Hz blue stimuli nor 3-Hz yellow stimuli., Conclusions: Results indicate that the b-wave recorded with 3-Hz blue stimuli is elicited from the S-cone system. This simple technique is useful for testing the human blue cone system.

Purpose: To study the function of the rod visual pathway in the complete and incomplete types of congenital stationary night blindness (CSNB), with special reference to the scotopic threshold response (STR) of electroretinograms (ERGs), Methods: Using full-field stimuli with light intensities ranging from near absolute threshold to bright, ERG intensity series from two patients with complete CSNB, four patients with incomplete CSNB, and four normal subjects were recorded., Results: Neither the rod b-wave nor the STR was recordable from the patients with complete CSNB. In the patients with incomplete CSNB, the STR was clearly recorded, although the absolute threshold was elevated in accordance with elevation of the psychophysical absolute threshold. The b-wave stimulus threshold was not elevated, and the b-wave amplitude near the threshold was normal. The peak time of the STR was delayed by approximately 80 msec, whereas that of the b-wave was normal., Conclusions: These STR results indicate that the rod system abnormality in complete CSNB differs from that in incomplete CSNB. Furthermore, the greatly delayed peak time of STR in the patients with incomplete CSNB made the interaction between b-wave and STR different from that in normal subjects.

We compared the amplitude and implicit times of the a-waves, b-waves, and oscillatory potentials of the focal macular electroretinograms of 30 eyes with aphakic cystoid macular edema and the healthy fellow eyes. Ten affected eyes were characterized by reduced amplitudes of the oscillatory potentials with normal a-wave and b-wave responses (type 1). Nine affected eyes had both reduced amplitudes of the oscillatory potentials and the b-waves (type 2). Ten affected eyes were characterized by reduced amplitude of the oscillatory potentials, the a-waves, and the b-waves (type 3). One eye could not be classified. Visual acuities were as follows: type 1, 0.55 (20/36.4); type 2, 0.31 (20/64.5); and type 3, 0.12 (20/166.7). The mean time between cataract surgery and the electroretinographic testing was significantly longer for type 2 and 3 eyes than for type 1 eyes. The differences in the electroretinographic responses between the affected eye and the normal fellow eye suggested either an increased severity or the stage of the cystoid macular edema.

Purpose: To study macular function of X-linked congenital retinoschisis (CRS) by focal macular electroretinogram (MERG)., Methods: MERGs were recorded with 5 degrees, 10 degrees, and 15 degrees spots in 20 patients with CRS. Seventeen patients showed foveal schisis with little or no change in foveal fluorescein angiography (Group 1), and three patients showed advanced macular changes with nonspecific macular degeneration (Group 2)., Results: In Group 1, a-wave amplitudes were within the normal range, but b-waves and oscillatory potentials (OPs) had mean amplitudes significantly below those for normal control subjects. The mean b- to a-wave ratios, significantly lower than in normal eyes, decreased significantly with decreasing spot size. The implicit times of a-waves, b-waves, and OPs were significantly delayed. In Group 2, MERGs were nearly nondectable., Conclusions: The macular pathology of CSR exists mainly in the middle and inner retinal layers, disturbing the fovea more than the perifovea, whereas degeneration of photoreceptors progresses in more advanced stage.

We describe optic atrophy and abnormal electroretinographic findings in affected members from two families. Central vision failed in the second to third decade of life. Examination findings included visual acuities of 20/20 (1.0) to 20/500 (0.4), defective color vision, mild to moderate myopia, pericentral or centrocecal scotomas, and, in four of five patients, optic atrophy. Dark adaptometry found elevated cone and rod psychophysical thresholds. Bright flash electroretinograms showed normal a-wave amplitude and markedly subnormal b-wave amplitude. Rod responses were low normal to moderately subnormal in amplitude with normal implicit times. Photopic electroretinographic b-wave amplitudes varied from normal to mildly subnormal. Cone implicit times were normal. Because negative electroretinograms are not seen with other familial optic atrophies, the association of optic atrophy with the abnormal negative electroretinogram configuration in these patients represents a newly appreciated genetic disorder.

To determine whether intraocular cooling using room-temperature irrigating solution can cause abnormal electroretinograph readings, we operated on six patients with premacular fibrosis and minimal retinal detachment, measuring the temperature in the vitreous cavity and using an electroretinographic monitor. The temperature in the vitreous cavity dropped to 27 degrees C to 28 degrees C after vitrectomies during which room-temperature solutions were used. This resulted in abnormal electroretinograph readings (markedly delayed peak times and reduced amplitudes). These results suggest that the routinely used room-temperature solution affects retinal function during vitrectomy; however, this functional change was reversible in patients having only minimal retinal abnormality.

We performed a pilot study of electroretinographic monitoring of retinal function during eye surgery performed with local anesthesia. A contact lens with a built-in light-emitting diode was sterilized and used as both a stimulus source and a recording electrode for 30-Hz flicker electroretinograms. Each recording required 7 seconds, during which the operating light (but not the room light) was switched off. Electroretinograms recorded during surgery on 10 patients with minimal retinal abnormality were evaluated for the effects of light adaptation caused by regular exposure to an operating light source or operating microscope. The fluctuations of the amplitude and peak time were small, indicating that this technique can be used to monitor retinal function during eye surgery. Some results during retinal and vitreous surgeries are shown.

Studies of the focal macular electroretinogram (ERG) have been made with special reference to oscillatory potentials (OPs) by using a fundus monitoring system in humans. Human macular OPs consist of 3 to 4 wavelets (mean peak interval, approximately 6.5 msec). The distribution of OPs in relation to those in a- and b-waves was studied. The amplitudes of a-waves, b-waves, and OPs of the upper macula were significantly larger than those of the lower macula. The distribution of OPs is relatively sparse in the fovea, becoming more dense than the a- and b-waves from the fovea toward the parafovea, and differing even more toward the perifovea. There was no statistical difference of amplitude in a- and b-waves between nasal and temporal macula. The amplitude of OPs in the temporal macula, however, was significantly larger than in the nasal macula. In some macular diseases, such as diabetic maculopathy, cystoid macular edema, or the convalescent stage of central serous chorioretinopathy, macular OPs were selectively reduced, leaving the a- and b-waves intact. Macular OPs can provide a new aspect of macular function and can be a sensitive indicator to assess that function in macular diseases.

The oscillatory potentials (OPs) in electroretinogram (ERG) have clinical values in measuring retinal functions of the early stage of diabetic retinopathy. However, OPs have, until now, been evaluated as components of total ERG recorded with a full field stimulus over the entire retina. Therefore, little information could be obtained about the macular condition (diabetic retinopathy). Using focal stimuli, we successfully recorded OPs in the human macular region. We modified our previously reported system for recording local macular ERG under the fundus monitor with an infrared television fundus camera. We evaluated macular OPs with simultaneously recorded a- and b-waves in many patients with diabetic retinopathy. In some kinds of early diabetic maculopathy, the macular OPs were selectively reduced, leaving the a- and b-waves intact. The macular OPs can be a valuable indicator in assessing the macular function in diabetic maculopathy.