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Purpose Assessing disease activity in Birdshot uveitis can be challenging. The peak time of the 30 Hz flicker photopic electroretinogram (ERG) was shown to be sensitive for detecting retinal dysfunction. ERG testing is not readily available in many eye units. We investigated use of a portable device to obtain recordings in the clinic setting and compared these with conventional recordings. Methods Patients underwent testing with the portable device (RETeval, LKC Technologies) and conventional equipment (Espion ColorDome, Diagnosys). For portable recordings pupils were undilated and skin electrodes used; for conventional recordings a conductive fibre electrode was used with mydriasis. Flicker ERG peak times were recorded and were deemed abnormal if they exceeded the 95th centile from a healthy cohort (>190 healthy volunteers). Results 18 patients with Birdshot uveitis underwent recordings. Recordings with the portable device took c. 3 min and were well‐tolerated. Mean (SD) age was 56.3 (12.8) years. For portable recordings, mean (SD) peak times were 30.1 (3.7) and 30.2 (3.9) ms for right and left eyes respectively. For conventional recordings mean (SD) peak times were 31.4 (3.9) and 31.8 (4.0) ms respectively. Peak times were significantly shorter with the portable device (p = 0.026 and 0.002 for right and left eyes). Correlation between devices was high (0.83 and 0.89 for right and left eyes) and highly significant (p < 0.0001). Strength of agreement between the two methods was good (kappa statistic 0.64; 95% CI, 0.36‐0.92). Conclusions Correlation between the portable and conventional ERG recordings was high with a good level of agreement. Recordings were rapid and well‐tolerated. There were significant differences in peak times between the two methods highlighting the importance of normative data specific to each device.

This case report describes ivermectin-induced blindness in a dog and a foal with normal ophthalmic fundic examinations and attenuated electroretinography (ERG). Subsequent recovery in ERG was noted following intravenous lipid emulsion (ILE) therapy. A dog and a foal were evaluated for ivermectin-induced blindness. Clinical signs included dull mentation, absent pupillary light reflexes (PLRs), and absent menace on presentation. The animals had normal fundoscopic examinations; however, in both cases ERG was consistent with neurosensory retinal dysfunction. Following ILE therapy for ivermectin toxicosis, return of menace, PLRs, and normal mentation were noted, as was improvement in ERG and serum ivermectin levels. These are the first documented cases of ivermectin-induced blindness in a dog and a foal with normal fundic examinations and attenuated ERG. ERG improved in both animals after ILE therapy. ERG may assist in the diagnosis of ivermectin toxicosis in dogs and horses. ILE therapy may hasten recovery in treatment of ivermectin-induced blindness.

The present study was undertaken in order to find out whether electroretinographic examinations could reveal signs of functional abnormalities before morphological changes are detected in the diabetic retina. Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded in 24 diabetics and 10 age-matched normal controls. The diabetic group consisted of 11 patients without retinopathy and 13 patients with background retinopathy. No significant changes in pattern-reversal or flash ERG or OP amplitudes were observed in the diabetic group with normal fundus or with background retinopathy. The findings imply that ERG examination with the described techniques does not reveal retinal dysfunction in diabetics before retinopathy can be detected by means of retinal biomicroscopy.

Raman microscopy is used to investigate the spectral features of selected compounds known to be involved in the development of the eye disease age-related macular degeneration (AMD). Diagnostic features were identified in synthetic samples of these compounds and in a biological matrix. The study demonstrates the potential of Raman microscopy for the development of diagnostic markers of the onset of AMD. Copyright © 2008 John Wiley & Sons, Ltd.

Purpose: Clinical investigation of central retinal dysfunction in two cases of solar retinopathy. Methods: Two patients were examined for best corrected visual acuity (VA), fundus inspection, visual fields, multifocal electroretinography (mfERG) with a stimulus pattern of 241 hexagons and, at follow-up, also with optical coherence tomography (OCT). Results: At the initial examination, mfERG revealed central retinal dysfunction, which had improved by the time of follow-up. In Case 1, a foveal oedema regressed over time, although VA remained slightly reduced. In Case 2, OCT showed spots of increased reflectivity corresponding to the patient's symptoms. Conclusion: Central retinal dysfunction due to solar retinopathy may improve over time. However, structural and functional changes may persist. This report illustrates that mfERG and OCT are useful tools for objective documentation of the pathology in solar retinopathy.

Purpose The importance of straylight derives from the fact that it reduces retinal sensitivity. This may be particularly relevant in conditions with retinal dysfunction, such as Retinitis Pigmentosa (RP). Moreover in RP often early in life PSC cataract develops. The question of this study is whether straylight substantially contributes to visual disability in RP patients, potentially aggravated due to the combination of retinal degradation and increased straylight from cataract formation. In addition, straylight was used to predict possible benefit of (early) cataract surgery. Methods Twenty-five RP patients scheduled for cataract extraction (CE) participated. Before and after CE, best corrected visual acuity (BCVA) in logMAR, contrast sensitivity (CS) in log(CS), temporal contrast sensitivity (TCS) in log(TCS), and straylight (log of the straylight parameter s, log[s]) were tested. TCS, or flicker sensitivity, was tested with a new test, using the C-Quant hardware. TCS measurement was performed to assess foveal function isolated from the eye’s optical quality. Results Average pre CE log(s) value was 1.72, corresponding to a factor 6 straylight increase as compared to a healthy, young eye. Functionally significant improvement defined as >0.2 log, was only found for log(s). Only log(s) improvement was related to pre CE values. LogMAR and log(TCS) were correlated (pre CE r(19)= .57, p< .01; post CE ρ(19)= .47, p< .05). Pre and post CE log(TCS) values were similar (p= .14). Conclusion Straylight effects of cataract may substantially aggravate visual disability in RP patients, whereas BCVA may (not yet) be affected. Loss of BCVA may reflect foveal function rather than cataract. For proper CE referral straylight must be assessed.

Purpose The ISCEV Standard for ERG does not include a measure of dark-adapted cone function. Prior to the introduction of the Standard, use of a red flash under dark-adapted conditions was a well-recognised part of ERG but its use appears subsequently to have declined. The purpose of the presentation is to demonstrate the importance of the dark-adapted red flash ERG in clinical ERG interpretation. Methods Retrospective case based presentation. Use of a red flash under dark adaptation can evoke an ERG in which there the early part of the waveform arises from the dark-adapted cone system and the latter part of the waveform from the rod system. The intensity of the red stimulus can be adjusted so that the rod-system derived part of the waveform has an amplitude similar to that of the rod specific ERG b-wave (DA 0.01). Results Cases will be shown where use of the dark-adapted red flash ERG enabled an improved interpretation of the bright flash ERG (DA 11.0). Disorders addressed will include fundus albipunctatus; vitamin A deficiency; RGS9 mutation (“bradyopsia”) and retinitis pigmentosa. An electronegative ERG waveform can occur arising in dark adapted cones, consistent with the so-called “photopic hill” phenomenon occurring in dark adapted cones exposed by an absence of rod function. The DA 11.0 ERG a-wave can reach in excess of 150µV under such circumstances, giving the potential for misdiagnosis of a form of inner retinal dysfunction such as may occur in CSNB. Conclusion The ISCEV Standard ERG waveforms are intended as a minimum data set. Use of a red stimulus under dark adaptation is a valuable addition to that data set and may prevent misinterpretation of the ISCEV Standard ERGs. The decline in the use of this ERG appears unjustified in routine clinical practice.

Purpose This presentation is to give a brief overview on the application of the multifocal electroretinogram (mf-ERG) in the clinic. Methods The use of m-sequences as a stimulus sequence allows a high resolution topographic mapping of sensory function. The mf-ERG can be readily applied to detect outer retinal dysfunction in the area of the macula. Different retinal layers contribute to the waveform of the mf-ERG. This results in typical changes of the waveform, when these different layers are dysfunct. Results MF-ERG examples are shown, that demonstrate how this knowledge can be useful in the clinical evaluation of patients. Conclusion The mf-ERG is a helpful tool in the clinical evalutation of patients.