Impact of regional retinal responses on cortical visually evoked responses: multifocal ERGs and VEPs in the retinitis pigmentosa model.

OBJECTIVE: To determine the impact of the regional retinal responses on cortical visually evoked responses, by evaluating the relationship between multifocal ERG (mfERG) and multifocal VEP (mfVEP), in the retinitis pigmentosa (RP) model. METHODS: MfERGs and mfVEPs were recorded from 20 typical RP patients. Response amplitude density (RAD, nV/deg(2)) and implicit time (ms) of the mfERG 1st order binary kernel (N1-P1) and mfVEP 2nd order binary kernel (P1) components were measured. Ring analysis, matched for mfERG and mfVEP stimuli, was performed between fovea and mid-periphery (0-2.5, 2.5-5, 5-10, 10-15 and 15-20deg). RESULTS: At central and pericentral retinal regions (four eccentricities between 0 and 15deg), mfERG N1 RADs were positively correlated (r0.68, p<0.01) with corresponding mfVEP P1 RADs. Similarly, mfERG P1 implicit times were positively correlated (r>or=0.65, p<0.01) with corresponding mfVEP N1 implicit times. CONCLUSIONS: There are quantitative correlations between mfERG and mfVEP components in RP. SIGNIFICANCE: The data suggest that regional responses of the photoreceptors and off-bipolar cells, the main generators of mfERG N1, have a major impact on the corresponding cortical activity.

Post-inflammatory retinal dystrophy in CINCA syndrome.

Right chorioretinitis and bilateral pseudopapilledema were firstly appreciated in a 9-month-old child with neonatal findings of aseptic chronic meningitis, framed in the context of CINCA syndrome at 1 year. Therapeutical response to various combinations of drugs was inconsistent until 7 years, when anakinra was started with immediate clinical and laboratory improvement. A state of severe retinal dystrophy of post-inflammatory origin became evident on funduscopy, optical coherence tomography and visual electrophysiology tests at the age of 10 years, which remained stationary after 1 year of anakinra treatment.

Lack of habituation in the light adapted flicker electroretinogram of normal subjects: a comparison with pattern electroretinogram.

OBJECTIVE: Sustained pattern stimulation (SPS) induces habituation in the normal pattern electroretinogram (PERG). In this study, the authors evaluated whether sustained flicker stimulation (SFS) induces habituation in the normal flicker ERG (FERG). METHODS: FERGs were elicited in normal volunteers by an 8Hz flicker stimulus, presented continuously over 3 min after 20 min of light adaptation. One stimulus temporal period was sampled and averaged in packets (n=20) of 60 events, each of 8s duration. Amplitudes and phases of the response 1st and 2nd harmonics (1F and 2F, respectively) were measured. FERG results were compared with those obtained by recording PERGs with a similar SPS paradigm. RESULTS: During SFS, FERG 2F showed a modest increase in amplitude (about 25%, p<0.05). No changes were observed for the 1F amplitude and for the phase of both components. In contrast, PERG amplitude showed SPS-induced habituation, described by an exponential decay with a time constant of approximately 20s. CONCLUSIONS: The normal FERG, unlike PERG, does not show habituation, suggesting that the adaptive changes of retinal neurons underlying FERG are different from those of PERG generators. SIGNIFICANCE: Our findings may have implications for diagnosis and/or pathophysiology of retinal disorders involving the inner retina.

Regional cone-mediated dysfunction in age-related maculopathy evaluated by focal electroretinograms: relationship with retinal morphology and perimetric sensitivity.

PURPOSE: To assess regional cone-mediated function in age-related maculopathy (ARM) by focal electroretinograms (FERGs), and to compare FERGs with morphologic changes and perimetric sensitivity at corresponding locations. METHODS: Twenty-six ARM patients and 12 age-matched controls were evaluated. FERGs were elicited by either a central (0-2.25 degrees , C) or a paracentral annular (2.25-9 degrees , PC) flickering (41 Hz) field, presented on a light-adapting background. Morphological changes (soft drusen and/or retinal pigment epithelium defects) at matched locations were assessed by fundus photography and fluorescein angiography. Perimetric sensitivity was measured by Octopus 10 degrees program (tM2). RESULTS: When compared to controls, mean C and PC FERG amplitudes of patients were reduced (p < 0.01), and the mean PC FERG phase was delayed (p < 0.01). Both FERG delays and morphologic lesions tended to involve to a greater extent the PC compared to the C region. In the C region, perimetric losses were correlated with the extent of morphologic lesions (p < 0.05). In the PC region, perimetric losses were correlated with FERG amplitudes (p < 0.05). CONCLUSIONS: In ARM, FERG losses are eccentricity-dependent, not quantitatively linked to retinal morphology, and correlated with perimetric losses, suggesting a heterogeneous dysfunction with loss of both C and PC perimetric sensitivities.

Effect of epigallocatechin-gallate on inner retinal function in ocular hypertension and glaucoma: a short-term study by pattern electroretinogram.

BACKGROUND: Epigallocatechin-gallate (EGCG) is a powerful antioxidant with suggested neuroprotective action. The aim of this study was to evaluate the effect of short-term supplementation of EGCG on inner retinal function in ocular hypertension (OHT) and open-angle glaucoma (OAG). METHODS: Eighteen OHT and 18 OAG patients (perimetric mean deviation: >-10 dB) were randomly assigned to assume oral placebo or EGCG over a 3-month period in a randomized, placebo-controlled, double-blind, cross-over design clinical trial (clinicaltrials.gov identifier: NCT00476138). Pattern-evoked electroretinograms (PERGs) to 1.6 cycles/degree square-wave gratings, counterphased at 16 reversals/second, and standard automated perimetry (Humphrey 30-2) were assessed at the study entry (baseline), and after 3 months of placebo or EGCG. RESULTS: After EGCG, PERGs of OAG, but not OHT patients were increased in amplitude, compared either to baseline values (mean amplitude change: 0.06 log microV, p < 0.05) or to PERG amplitude values found in the same patients after placebo administration (mean change: -0.02 log microV, p not significant; difference between EGCG and placebo: 0.08 log microV, p < 0.05). In both OHT and OAG patients, standard automated perimetry did not show significant changes after either EGCG or placebo. In individual OAG patients, the magnitude of PERG amplitude increment after EGCG was inversely related (r = -0.8, p < 0.01) to corresponding baseline amplitudes. CONCLUSIONS: Although this study cannot provide evidence for long-term benefit of EGCG supplementation in OAG, and the observed effect is small, the results suggest that EGCG might favourably influence inner retinal function in eyes with early to moderately advanced glaucomatous damage.

Morpho-functional follow-up of the optic nerve in treated ocular hypertension: disc morphometry and steady-state pattern electroretinogram.

PURPOSE: To examine longitudinally optic disc structure and inner retinal function in treated ocular hypertension (OHT). MATERIALS AND METHODS: A morphometric (Heidelberg Retina Tomograph, HRT) and functional (steady-state pattern electroretinogram, PERG) evaluation of 27 OHT patients treated with topical beta-blockers and/or prostaglandin analogues and prospectively followed over a 24 +/- 6 month period. RESULTS: Compared with baseline, mean final PERG amplitude tended to increase (p < 0.01), while HRT was stable. Individual PERG amplitude increase was large (>or= 100%) in some patients (5/27), and unexplained by clinical parameters at baseline. CONCLUSIONS: In treated OHT, functional responses may improve while disc structure remains stable. The findings suggest that OHT-associated inner retinal dysfunction is at least in part reversible with therapeutic intraocular pressure control.

Structure-function relationship in ocular hypertension and glaucoma: interindividual and interocular analysis by OCT and pattern ERG.

BACKGROUND: Pattern electroretinogram (PERG) and optical coherence tomography (OCT) represent objective probes to investigate respectively the function of retinal ganglion cells and their structure as retinal nerve fiber layer (RNFL) thickness. We examined interindividual (II) correlations of PERG amplitude and RNFL thickness, as well as correlations between interocular (IO) differences in both measures, in ocular hypertension (OHT) and early glaucoma (EG) patients. METHODS: Thirty-one OHT, 34 EG (mean deviation: -1 to -6 dB) and 16 age-matched controls were examined in both eyes. Participants had clear optical media, no or moderate refractive errors and no concomitant ocular or systemic diseases. PERGs were elicited by counterphased (16.28 reversals/second) gratings (1.6 cycles/degree spatial frequency). The Fourier isolated 2nd harmonic PERG amplitude and phase were measured. RNFL thickness was quantified by means of OCT Stratus according to a standard protocol. Average, superior and inferior RNFL thicknesses were considered. RESULTS: Mean PERG amplitude was decreased (p < 0.01) in both OHT and EG patients compared to controls. Mean RNFL thicknesses were reduced (p < 0.01) in EG patients compared to both OHT and controls. In OHT patients, PERG amplitude did not correlate significantly with RNFL thickness in both II and IO analysis. In EG patients, PERG amplitude was positively correlated with RNFL thickness in both II (p < 0.005) and IO (p < 0.001) analysis. The slope of the correlation predicted that PERG losses exceeded systematically RNFL losses when the latter were between 0 and -0.25 log units. CONCLUSIONS: Both II and IO analyses revealed a lack of structure-function relationship in OHT, suggesting that, at this disease stage, PERG losses appear to affect primarily retinal/optic nerve head function. In EG they reflect both dysfunction and RNFL loss.

Temporal response properties of the macular cone system: effect of normal aging and age-related maculopathy.

PURPOSE: To evaluate the influence of aging and age-related maculopathy (ARM) on the temporal frequency response function (TFR) of macular focal electroretinography. METHODS: Macular (18 degrees ) focal electroretinograms (FERGs) in response to sinusoidal flicker, modulated at TFs between 3.7 and 52 Hz, were recorded from 13 young (age range, 14-29 years) and 9 old (age range, 55-80 years) healthy subjects and from 18 patients with ARM (stage 2 disease; age range, 55-80 years; visual acuity >/=0.4). Amplitude and phase of the Fourier-analyzed response fundamental (1F) and seconnd harmonic (2F) were measured. RESULTS: In young healthy subjects, mean 1F TFR showed a maximum amplitude at 41 Hz, a secondary peak at 3.7 Hz, a minimum at 8 Hz, and a high TF (32-52 Hz) roll-off. Mean 1F TFR of old, compared with young, healthy subjects showed amplitude enhancement at 10 to 14 Hz and a small loss at high TF. Mean 2F TFR of young and old healthy subjects had a maximum at 5.7 to 8 Hz and an attenuation beyond 10 Hz. Mean 1F and 2F TFRs of ARM patients were similar to those of old healthy subjects but were depressed in mean amplitude. FERG TFR changes of old healthy subjects and ARM patients were not mimicked by reducing stimulus retinal illuminance or modulation depth in young healthy subjects. CONCLUSIONS: FERG temporal properties are affected by normal aging and ARM. Because FERG TFR is shaped mainly by postreceptoral activity, the findings suggest that photoreceptor and postsynaptic dysfunction underlie aging- and ARM-related FERG changes.

Regional assessment of cone system function following uncomplicated retinal detachment surgery.

PURPOSE: To evaluate regional cone system function after uncomplicated retinal detachment (RD) surgery, by recording focal electroretinograms (FERGs) from the central and paracentral regions of the posterior pole. METHODS: FERGs in response to either a central (eccentricity: 0-2.25 deg) or a paracentral annular (2.25-9 deg) uniform field, presented on a light adapting background and sinusoidally flickered at 41 Hz (95% modulation depth, 93 cd/m(2) mean luminance) were recorded from 16 eyes (16 patients) 2 weeks to 420 months following uncomplicated RD surgery (encircling procedure with or without scleral buckling). Pre-operatively, 10 out of 16 eyes had a macular RD. Mean time elapsed from onset of symptoms to surgery was 20 days (range: 5-90 days). Post-operatively, visual acuity ranged 0.1 to 1.0. Eight age-matched normal subjects served as controls. Amplitude and phase of the FERG fundamental harmonic were measured. RESULTS: Compared to control eyes, affected eyes' central and paracentral FERGs were on average reduced in amplitude (by 40% and 28%, respectively, p<0.01) and delayed in phase (by 70 and 100 degrees, respectively, p<0.01). Eyes with a macular RD did not differ in FERG amplitude or phase from eyes that had a peripheral RD. In individual affected eyes, central, but not paracentral FERG amplitudes were negatively correlated (p=0.05) with time elapsed from onset of symptoms to surgery. CONCLUSIONS: Central and paracentral cone system dysfunction may be detected even at lengthy time intervals from retinal reattachment, independent of the presence of a pre-operative macular RD. The extent of central loss appears to be inversely related to RD duration, in agreement with previous reflectometric findings on foveal cone photopigment density [Liem et al., 1994; Ophthalmology 10: 1945-51].

Successful MARS treatment in severe cholestatic patients with acute on chronic liver failure.

Extracorporeal liver devices have gained great attention as a complementary approach to liver transplantation in patients with acute on chronic liver failure. Among others, Molecular Adsorbent Recycling System (MARS) is a hemodiafiltration against albumin able to remove low molecular weight toxins. We aimed to validate the use of MARS in patients presenting with acute on chronic liver failure with severe cholestasis. We enrolled 7 patients with acute on chronic liver failure, presenting with bilirubin >25 mg/dl and hepatorenal syndrome and/or hepatic encephalopathy grade >II. Liver biochemistry, coagulation, blood cell count, electrolytes, ammonia, lactate, blood urea nitrogen, creatinine, bile acids, Fischer ratio, and encephalopathy grade were assessed before and after each MARS treatment. MARS can represent a safe therapeutic choice to achieve a quick improvement of neurological status, a hemodynamic stability, and a better clinical outcome. In particular, our encouraging results suggest that also, patients with severe cholestasis may represent in the future a good indication for MARS treatment.