P1 01 Effect of nutraceutical supplementation on redox status and mfERG on retinitis pigmentosa patients
Emiliio González-García1, Lorena Olivares-González2,3, David Salom4,5, David Hervás6, Natalia Mejía-Chiqui2, Mar Melero7, Sheyla Velasco2, Bianca T. Muresan8, Isabel Campillo2, Nieves Vila-Clérigues7, Eduardo López Briz7, Juan Francisco Merino-Torres9,10, Jose María Millán3,5,11, Jose Miguel Soriano Del Castillo10,12, Regina Rodrigo13,3,5
1Manises Hospital, Department of Neuroscience, Valencia, Spain. 2Principe Felipe Research Center (CIPF), Valencia, Spain. 3Joint Research Unit on Rare Diseases CIPF-Health Research Institute Hospital La Fe (IIS-La Fe), Valencia, Spain. 4Manises Hospital. Department of Ophthalmology, Valencia, Spain. 5Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid, Spain. 6Universitat Politècnica de València, Department of Applied Statistics, Operations Research and Quality, Valencia, Spain. 7Service of Pharmacy, La Fe University and Polytechnic Hospital, Valencia, Spain. 8Service of Endocrinology and Nutrition, University General Hospital, Valencia, Spain. 9Service of Endocrinology and Nutrition, La Fe University and Polytechnic Hospital, Valencia, Spain. 10Joint Research Unit on Endocrinology, Nutrition and Clinical Dietetics UV-IIS La Fe, Valencia, Spain. 11Molecular, Cellular and Genomic Biomedicine, IIS-La Fe, Valencia, Spain. 12Food & Health Laboratory, Institute of Materials Science, University of Valencia (UV), Valencia, Spain. 13Pathophysiology and Therapies for Vision Disorders, Principe Felipe Research Center (CIPF), Valencia, Spain
Purpose Oxidative stress plays a major role in the pathogenesis of retinitis pigmentosa (RP). The main goal of this study was to evaluate the effect of a two-year nutritional intervention with antioxidant nutraceuticals on the visual function of RP patients. Secondly, we assessed how nutritional intervention affected ocular and systemic redox status.
Methods We carried out a randomized, double-blind, placebo-controlled study called NUTRARET. Thirty-one patients with RP participated in the study. RP patients randomly received either a mixture of nutraceuticals (NUT) containing folic acid, vitamin B6, vitamin A, Zinc, Copper, Selenium, lutein, and zeaxanthin or placebo daily for two years. At baseline and after two years of nutritional supplementation, visual function, dietetic-nutritional evaluations, serum concentrations of nutraceuticals, plasma and aqueous humour concentrations of several markers of redox status and inflammation were assessed. Retinal function and structure were assessed by multifocal electroretinograms (mfERG), optical coherence tomography, and visual field tests. Nutritional status was estimated through questionnaires. Total antioxidant capacity, extracellular superoxide dismutase (SOD3), catalase (CAT) and glutathione peroxidase (GPx) activities, carbonyl adducts (CAR) content, thiobarbituric acid reactive substances (TBARS) formation (as indicator of lipid peroxidation), metabolites of the nitric oxide and cytokine (IL6 and TNFα) concentration were assessed by biochemical and immunological techniques in aqueous humour or/and blood. Bayesian approach was performed to determine the probability of an effect. Region of practical equivalence (ROPE) was used.
Results At baseline, Bayesian analysis revealed a high probability of an altered ocular redox status and to a lesser extent systemic redox status in RP patients compared to controls. Twenty-five patients (10 in the treated arm and 15 in the placebo arm) completed the nutritional intervention. After two years of supplementation, patients who received NUT presented better retinal responses (mfERG recordings) compared to patients who received placebo. The changes studied show significant evidence, especially in the sum of all sectors of the mfERG. Patients who received NUT also showed better ocular antioxidant response (SOD3 activity) and lower oxidative damage (CAR) than those who received placebo.
Conclusions This study suggests that long-term nutraceutical supplementation could improve or at least slow down visual impairment and ameliorate ocular oxidative stress.
Acknowledgements We are very grateful to the patients and their relatives for their participation. We thank RETINA COMUNIDAD VALENCIANA for its help on the recruitment of the participants and co-operation with the nutraceutical distribution, especially to Melani Navarro Lon, Almudena Amaya, and José Joaquín Gil. We would like to thank Biobank of the Hospital Universitari i Politècnic La Fe for supplying blood samples from controls. Thanks to Regina Rodrigo and Principe Felipe Research Center (CIPF).
P1 03 A novel approach to analyse white noise ERGs in mice
Nina Stallwitz1,2, Anneka Joachimsthaler1,2, Jan Kremers1
1University Hospital, Erlangen, Germany. 2Friedrich-Alexander Universität, Erlangen-Nürnberg, Germany
Purpose To analyse correlations between white noise ERGs (wnERGs) recorded to luminance modulating and single opsin isolating temporal white noise (TWN) stimuli.
Methods Mice were dark adapted overnight and all further handling was done under dim red light. Using mice that express a long-wavelength sensitive L-Opsin instead of the murine M-Opsin enables the isolation of single opsin-driven ERGs by combining the TWN stimulus with the silent substitution method (52% rod-contrast, 48% L-cone contrast, 77% S-cone contrast). Recordings of the anesthetized animals were performed at different mean luminances (ML), and each recording was performed twice. TWN stimuli (containing all frequencies up to 20 Hz with equal amplitudes and random phases) were luminance modulation (100% contrast white light) and shown at MLs ranging from − 0.7 to 1.1 log cd/m2. In addition, opsin isolating stimuli were employed at MLs between − 0.8 and 1.0 log cd/m2. The reproducibility of the wnERGs was quantified using a correlation coefficient. The ERG potentials at identical instances during the repeated measurements at one ML and condition were plotted against each other. The correlation coefficient of the linear regression through the data was extracted (r2repr). Correlation coefficients vary between 1, meaning complete accordance of both results, and 0, indicating no similarities at all. To investigate whether the change in appearance of the wnERGs depend on ML, another correlation coefficient was used (r2ML). To receive r2ML, the two repeated recordings at each ML were averaged and the averaged wnERG of each ML was either plotted against the wnERG obtained at the lowest ML (for rod isolating and luminance stimuli) or highest ML (for cone isolating and luminance stimuli). The linear regression through the data gave the correlation coefficient r2ML to quantify the correlations between responses at different MLs.
Results For luminance stimuli, r2repr values decreased with increasing ML up to − 0.1 log cd/m2 ML, above which r2repr increased with increasing ML and reached a plateau for MLs higher than 0.5 log cd/m2. r2repr values for rod-driven wnERGs were maximal at low MLs and decreased for MLs higher than 0.4 log cd/m2, whereas r2repr values for S-cone-driven wnERGs initially decreased up to a ML of − 0.2 log cd/m2 and then increased. The r2repr values for L-cone-driven ERGs continuously increased with increasing ML. R2ML values for luminance modulation decreased with increasing ML when the responses were plotted against those obtained at the lowest ML, whereas they increased when plotted against the responses obtained at the highest ML. For L- and S-cone-driven ERGs, r2ML values increased with increasing ML, whereas r2ML values decreased with increasing ML for rod-driven wnERGs.
Conclusions Differences between the characteristics of the r2 values between rods and cones point at fundamental differences of the dynamics of the ERG origins. Luminance ERGs originate in rods at low MLs and in cones at high MLs. Responses at intermediate MLs are generally weak.
Acknowledgements Section for Retinal Physiology, University Hospital Erlangen. Animal Physiology, FAU Erlangen-Nürnberg.
P1 05 The annual carbon footprint of a visual electrodiagnostic service
Joanne Cowe, Julie Kempton
University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
Purpose To combat global heating, the National Health Service (NHS) in England has committed to ‘net-zero’ by 2040 with an ambition to reduce the NHS carbon footprint by 80% by 2028–2032 [NHS England and NHS Improvement (2020), Delivering a ‘Net Zero’ National Health Service, Publication approval reference: PAR133]. Greenhouse gases are emitted at all stages of the electrodiagnostic process from procurement, activity (patient testing), production of goods/services (e.g. patient reports), and from waste. A carbon footprinting methodology for an electrodiagnostic service is described. An estimate of the annual carbon equivalent footprint of our service is presented for the calendar year 2021.
Methods The carbon dioxide equivalent emissions were calculated for energy use, water use, procurement, waste, and travel (staff business travel, commuter travel, and patient travel). UK Government GHG Conversion Factors for Company Reporting were used to find the carbon dioxide equivalent emissions for staff commuter travel, hotel stays for business travel, and for water use. The carbon dioxide emission for patient travel and business travel was estimated using the carbon calculator from the Centre for Sustainable Healthcare (“Carbon footprint calculator for (avoided) patient travel”). Departmental spend in various procurement categories was converted using weighting factors provided by the Greener NHS team (https://www.england.nhs.uk/greenernhs/). The Royal Mail Letter Carbon Calculator was used to calculate emissions from the postal service. Emissions from energy use were calculated as a proportional fraction of the building’s total carbon emissions stated on the Display Energy Certificate (DEC). Consumable waste was converted using GHG emissions factors from a waste stream study (Rizan C. et al., J Cleaner Production, 2021; 286:a125446).
Results The total estimated 2021 carbon footprint for our electrodiagnostic service was 24.95 tonnes CO2e. Some emissions such as those from use of personal protective equipment and office waste could not be quantified making this a lower bound for our service. The results from each category were: energy: 15.43 tonnes CO2e (62%); travel: 7.61 tonnes CO2e (30%); procurement: 1.90 tonnes CO2e (8%); waste: 0.01 tonnes CO2e (0%); and water: 0.01 tonnes CO2e (0%). The primary contributors to the carbon footprint, together accounting for 92% of the total, were therefore energy use followed by patient and staff travel. Visual electrodiagnostics carried out 237 patient appointments in 2021. The average carbon footprint per patient is therefore 105 kg CO2e which could allow for more meaningful comparison between larger and smaller test centres.
Conclusions The NHS produced an estimated 6.1 MtCO2e in 2020 (NHS England and NHS Improvement (2020), Delivering a ‘Net Zero’ National Health Service, Publication approval reference: PAR133). To reduce this to net zero it is clear that every part of the NHS will need to contribute, including its suppliers. The results encourage us to make more efficient use of energy in our area. We could consider the use of satellite clinics to bring testing closer to patients. We can also promote more sustainable forms of transport for our staff and in our patient communications such as sign posting to public transport.
P1 07 The effect of fixation location on full-field ERG waveforms
David T Murray, Julie Kempton, Joanne Cowe
Medical Physics Department, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
Purpose When performing a full-field ERG, patients are requested to look at the central fixation spot within a Ganzfeld dome. Some patients find this difficult and either consistently look elsewhere in the dome or vary their gaze position during the test. This study analyses the clinical impact of fixating at alternative locations.
Methods ERG recordings were performed on 14 eyes using our light-adapted 3.0 ISCEV protocol (but without dilation), with DTL electrodes placed at the junction where the lower eyelid meets the sclera/cornea. Eleven different gaze locations were used within the Ganzfeld: central, 3 eccentricities in both nasal and temporal directions, and 2 eccentricities in both superior and inferior directions. Volunteer were asked to keep their head facing forwards and only move their eye to the various positions. A- and b-wave amplitudes and peak times were analysed to assess the clinical impact of gaze position.
Results Data from one subject (both eyes) were excluded, as both a- and b-wave amplitude and peak time measures were outside our reference ranges for the standard central fixation. While this is a small study including only 12 eyes, the results indicate that the amplitude is more susceptible to changes in the gaze position than peak time, with a-wave and b-wave amplitudes being markedly affected. An overall amplitude increase is seen when looking superiorly, i.e. above the central fixation light, whilst looking to either extreme side or downwards results in a reduction in the amplitude. A mean b-wave amplitude reduction of 38% was seen in a fully downwards position, while a partial downwards gaze caused a mean reduction of 22%, relative to the standard central fixation position. Conversely, an increase of 46% was seen on the a-wave amplitude and an increase of 10% on b-wave amplitude while looking in the full up position. The maximum deviation from the peak time measured in the central position was smaller, with a mean delay of 8% on the a-wave and 3% on the b-wave, both when eyes were looking in the full down position.
Conclusions The central fixation point should always be used during testing. Patients should be monitored for compliance during testing using an IR camera, with any notable deviations recorded. A variance in fixation direction could push a result in or out of a reference range(s), potentially impacting report conclusion. This highlights the need for repeatability, consistency, and the importance of monitoring compliance, not only in patient testing but also in the collection of the normative data with which patient data will be compared.
P1 09 Morphological and electrofunctional evaluation of ganglion cells in pre-perimetric glaucoma
Viviana D'Alterio1, Gennaro Ambrosio1, Ciro Costagliola1, Lucia Ambrosio1,2
1Eye Clinic Department of Neuroscience, Reproductive and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy. 2Department of Public Health, University of Naples Federico II, Naples, Italy
Purpose PERG testing was used to assess functional changes of retinal ganglion cells after decrease of intraocular pressure in patients with early stage (pre-perimetric) glaucoma. This study showed that an early and reversible window of time may exist, during which retinal ganglion cell dysfunction (prior to axonal loss) is clinically associated with normal optic nerve parameters by spectral-domain optical coherence tomography (SD-OCT).
Methods Twenty-eight patients (56 eyes) with pre-perimetric glaucoma were studied retrospectively between January and December 2019. Fourteen patients/28 eyes, aged 45.6 ± 8.7 years, had been treated with topical eye drops (Timolol 0.5%); 14 patients/28 eyes, aged 42.8 ± 7.8 years, had not received any therapy. The steady-state PERG was recorded using an optimized paradigm for glaucoma screening (PERGLA, GLAID, Ingenesi, Italy) at baseline and after 12 months of treatment. Patients’ intraocular pressure had been measured with the Goldmann tonometer every 2 months. The thicknesses of the ganglion cell complex (GCC) and retinal nerve fiber layer were measured using RTVue SD-OCT imaging. Focal loss volume (FLV) and overall loss volume (GLV) were calculated and collected at baseline.
Results During follow-up, good compliance to the treatment was noted. Decrease of ocular pressure was documented in the treated patients. PERG was recorded for all patients at baseline and after 12 months of treatment. PERG response amplitudes (µV) were compared with the normative values available with GLAID software. A statistically significant effect between the treated (pre-treatment 0.98 ± 0.26; after 12 months 1.19 ± 0.3) and untreated groups (1.05 ± 0.23; after 12 months 0.77 ± 0.24) was found in the PERG amplitudes (µV) (p < 0.001).
Conclusions Reducing intraocular pressure in patients with suspected (pre-perimetric) glaucoma results in functional recovery of retinal ganglion cells that are still in a transitional stage and that retain the normal structure of GCC.
P1 11 Investigating the relationship between visual electrophysiology results, phenotype and genotype of patients assessed at an ocular-genetics service
Clodagh Duffy1,2, Sarah Francis1,2, David F. Gilmour1, Daniela T. Pilz1,3, Sinead M. Walker1,2
1Glasgow Centre for Ophthalmic Research, Gartnavel General Hospital, Glasgow, United Kingdom. 2Medical Devices Unit, Glasgow, United Kingdom. 3West of Scotland Genetics Service, Queen Elizabeth University Hospital, Glasgow, United Kingdom
Purpose A monthly joint ophthalmic and genetics multidisciplinary team (MDT) clinic has been operational at Glasgow Centre for Ophthalmic Research (GCOR) for almost 10 years. Most patients have visual electrophysiology (EP) testing and ophthalmic imaging performed prior to attending the clinic and virtually all have genetic testing conducted following their clinic attendance, typically using the Manchester Retinal Degeneration Panel. An audit was performed to investigate the relationship between visual electrophysiology results, phenotype and genotype of patients who attended the clinic in 2019.
Methods Ophthalmology, visual electrophysiology and genetics records were examined from all patients. The audit aimed to determine what proportion of patients:
Had a positive genetics panel outcome.
Had visual EP results that were in alignment with their phenotype.
Had visual EP results that were in alignment with their genotype.
Results 54 patients attended the clinic in 2019; 8 were discounted from the audit for various reasons including pending genetics results. 42 of these 46 patients from the sample group underwent genetic testing. 28 (66.7%) of these patients had a positive genetics panel outcome, 9 (21.4%) had a negative genetics panel outcome, and 5 (11.9%) were borderline. Of these borderline results, 2 (4.8%) detected a mutation of uncertain significance, and 3 (7.1%) identified only a single gene mutation where two would have been documented to be pathogenic. 44 patients (95.7%) had EP results that aligned with their phenotype. Of the 28 patients who had a positive genetics panel outcome, 25 (89.3%) had EP results that were in alignment with their genotype.
Conclusions The 66.7% (n = 42) of patients in the sample group who received genetic testing and had a pathogenic mutation identified is similar to the results of an audit performed in 2017, in which 69.2% (n = 32) of patients had a positive Manchester Retinal Degeneration Panel outcome. The vast majority of patients (95.7%) had EP results that were in alignment with their phenotype, which indicates that visual EP is an accurate way to confirm a patient’s phenotype. The visual EP results were also highly aligned with the patient’s genetics outcome, with 89.3% of patients having visual EP results that were in keeping with their genotype. The audit confirmed that visual electrophysiology is a valuable tool to confirm that patients referred to the MDT have phenotypes resulting from pathology that is in keeping with genetic conditions and helps to ensure that only appropriate patients are referred for genetic testing.
P1 13 Flicker ERG in preterm infants
Aylin Taner1, James V. M. Hanson1, Caroline Weber2, Dirk Bassler2, Daphne L. McCulloch3, Christina Gerth-Kahlert1
1Department of Ophthalmology, University Hospital Zurich and University of Zurich, Zurich, Switzerland. 2Newborn Research, Department of Neonatology, University Hospital Zurich and University of Zurich, Zurich, Switzerland. 3School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
Purpose Infants born prematurely are at risk of developing retinopathy of prematurity (ROP) which has been associated with abnormalities in conventional ERGs. We have reported non-invasive flicker ERGs in term infants; the aim of this study was to measure and analyze non-invasive flicker ERGs of preterm and very preterm infants. The long-term goal of the study is to evaluate the utility of flicker ERG as a diagnostic tool to assess children at risk for ROP.
Methods Flicker ERGs of moderate preterm (gestational age (GA) 34 0/7 to 36 6/7 weeks, group A) and extremely and very preterm (GA ≤ 31 weeks, group B) infants were recorded at the University Hospital Zurich. Uniocular measurements were performed within the first week of life (group A) and between 34 and 37th week postmenstrual age (PMA) (group B) while infants were asleep. Flicker stimuli were presented through closed eyelids at 28.3 Hz, with stimulus levels of 3, 6, 12, 30, and 50 cd s/m2, using the portable RETeval® device and disposable skin electrodes. Two measurements per stimulus level were recorded and averaged after checking for reproducibility. Primary endpoints were peak time (ms) and amplitude (µV) for each stimulus. Statistical analysis was performed in SPSS®.
Results Data of 59 infants were analysed (group A: 40, group B: 19 including 1/19 with ROP stage 1, zone II at the time of testing). With increasing stimulus levels, flicker ERGs were more often reproducible, with the highest reproducibility at 30 cd s/m2 (52/59 infants). Amplitudes increased with stronger flicker (Kruskal–Wallis-H Test, p < 0.001), while peak times did not differ significantly between stimulus levels. As not all data were normally distributed, comparison between groups A and B was made using the Mann–Whitney-U Test. Significantly higher amplitudes at stimulus levels 12 and 50 cd s/m2 (exact Mann–Whitney-U-Test: Z = − 2.037, p = 0.042 and Z = − 3.788, p ≤ 0.001, respectively) were evident in group B. Cohen’s effect size is medium at 12 cd s/m2 (0.30) and large at 50 cd·s/m2 (0.55). No inter-group differences in peak times were detected.
Conclusions Feasibility of collecting flicker ERG data in the majority of preterm infants was confirmed in this study. Although the groups were comparable in terms of PMA at the time of data collection, extremely and very preterm infants seem to have higher amplitudes in two stimulus levels than moderate preterm infants. However, no difference was found between the two groups for the lower stimulus levels nor for the peak times. The difference detected could indicate acceleration of retinal development following birth, triggered by visual stimulation. Data collection in Group B is ongoing.
P1 15 Unusual OCT findings in a patient with CABP4-associated retinopathy
Jit Kai Tan1,2, Omar Mahroo3,4
1GKT School of Medical Education, London, United Kingdom. 2UCL Institute of Ophthalmology, London, United Kingdom. 3Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. 4Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
Purpose Bi-allelic variants in CABP4 are associated with congenital cone-rod synaptic disorder, also known as incomplete congenital stationary night blindness (iCSNB). Patients show characteristic electroretinogram (ERG) abnormalities, and fundus findings are typically reported as normal. We describe clinical findings in a patient, who demonstrated an unusual macular optical coherence tomography (OCT) phenotype, not previously reported.
Methods The patient was assessed clinically and also underwent spectral domain OCT imaging (Spectralis, Heidelberg Engineering, Heidelberg, Germany) and international standard full-field ERG testing (Diagnosys Colordome, Diagnosys UK, Cambridge, UK) with conductive fibre electrodes placed in the lower conjunctival fornices. Genetic testing was performed via whole genome sequencing. Frequency of likely pathogenic variants found were assessed in the online Genomes Aggregation Database (gnomAD).
Results The patient was a 60 year old Caucasian woman. She reported lifelong non-progressive visual impairment since birth and a preference for dim lighting, for which she wore dark tinted contact lenses. She had a history of multiple squint surgeries, nystagmus, fibromyalgia, sleep apnoea, and arthritis. Clinical fundus examination was largely unremarkable. OCT imaging revealed a hypo-reflective zone under an elevated fovea in both eyes. ERG testing showed an electronegative dark-adapted ERG, with severely abnormal light-adapted responses consistent with iCSNB. Whole genome sequencing revealed that the patient was homozygous for a novel variant in CABP4 (a premature stop at codon position 111); this variant was absent from the gnomAD database. No other variants were found that could explain the patient’s phenotype.
Conclusions The OCT findings of foveal elevation and an underlying hyporeflective zone are novel in this condition. Whilst the patient’s clinical history was similar to that seen in achromatopsia and other cone dysfunction syndromes, the ERG findings pointed to iCSNB, which is associated with CACNA1F and CABP4. As CACNA1F is X-linked, and our patient was female, CABP4 was likely and was confirmed on genetic testing. Although the variant was novel, the highly specific ERG phenotype made this the likely cause. The patient saw better in dim light, confirming that “night blindness” is a misnomer in CABP4-associated disease. Our case highlights the value of ERG testing in discriminating between causes of cone dysfunction and also extends the range of phenotypes and genotypes reported in this disorder.
P1 17 How onset VEP can help in neurosurgical decision-making in infants.
Eszter Mikó -Baráth1,2, Valéria Gaál3, János Radó1,2, Gábor Jandó1,2
1Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary. 2Centre for Neuroscience, University of Pécs, Pécs, Hungary. 3Department of Ophthalmology, Medical School, University of Pécs, Pécs, Hungary
Purpose To follow up on an infant with nystagmus and lack of visual attention, having a space-occupying lesion in the posterior cranial fossa proven by Magnetic Resonance Tomography (MRT). Here we demonstrate how the 14 months-long regular VEP testing supported the neurosurgical decision making.
Methods The patient was observed between 4 and 19 months of age. Regular orthoptic examination and checkerboard onset-VEP were performed to 120-7′ check sizes five times in accord with the ISCEV standard. VEPs were evaluated manually and by using T2circ statistics, focusing on the presence of stimulus-related responses. The peak times of C1 and C2, comparison of monocular records, and occurrence of responses for the smaller check sizes were monitored. MRT was carried out under anesthesia at 4 and 12 months of age.
Results At 4 months of age, a continuous large-amplitude, slow-wave horizontal nystagmus, a sluggish pupillary reaction, and lack of fixation and following light target suggested severely impaired visual function or even blindness in the otherwise healthy boy. Ophthalmoscopy revealed a healthy disc and fundus, and cycloplegic retinoscopy was normal for age at each examination. The first MRT revealed a cystic space-occupying lesion (9 × 10 × 12 mm) compressing the right optic tract and dislocating the hypothalamus. These findings suggested an arachnoid cyst and posed the necessity of neurosurgical intervention, which would have been a complicated and risky operation. Onset VEP results suggested the presence of pattern recognition in both eyes at 4 months. Next, a gradual improvement in the wave morphology indicated the development of fairly good visual function. The surgery was postponed and the careful follow-up was continued. At 1 year of age, a significant regression (3 × 5 mm) of the cerebral inhomogeneity was observed in the repeated MRT. No compression of the chiasmatic region and normal myelination of the optic tract could be seen. At the age of 16 months, responses to the smallest check sizes appeared.
Conclusions Arachnoid cysts are quite common, mostly asymptomatic and harmless findings among infants. In some rare cases, their surgical removal may be necessary when causing severe compression to major brain structures. When the morphological alteration does not accompany functional impairment, surgery can be postponed. In this infant, the careful follow-up by using onset-VEP guided the clinical decision-making. The nystagmus is still present at a slower frequency and it might be associated with hemianopia. The overall visual function of the toddler seems to be satisfying.
P1 19 Comparison of mfERG recordings with DTL and gold cup skin electrodes
Khaldoon O. Al-Nosairy, Theresa Eckermann, Michael B. Hoffmann
Otto-von-Guericke, Magdeburg, Germany
Purpose: (i) To compare mfERG recordings between DTL and gold cup skin electrodes in healthy young and old adults and (ii) to test the sensitivity of both electrodes to age-related changes in the responses.
Methods: Twenty participants aged 20–27 years (“young”) and 20 participants aged 60–75 (“old”) with a visual acuity of ≤ 0 [logMAR] were included. The mfERG recordings were acquired using a 61-field stimulus spanning 5 eccentricities, using the VERIS Science 6.4.9d13, and complied with the ISCEV standard . The mfERG responses were recorded simultaneously using DTL and skin electrodes placed along the lower lid and 5 mm below the lid margin. The outcome measures were the comparison and correlations of P1 amplitudes, peak times, and signal-to-noise ratios (SNRs) of the mfERG between electrodes and age groups. Furthermore, each electrode’s performance in discriminating responses between the age-groups was tested using area under curve (AUC) of receiver operating characteristics.
Results: Both electrodes reflected the typical waveform of mfERG recordings. The skin electrode, however, resulted in significantly (p < 0.001) smaller P1 amplitudes (DTL young [old]: 841.8 ± 182.13 nV [643.18 ± 170.46 nV], gold cup young [old]: 232.57 ± 68.68 nV [189.53 ± 42.87 nV]), shorter peak times (DTL young [old]: 33.2 ± 1.12 ms [35.29 ± 1.61 ms], gold cup young [old]: 31.58 ± 1.14 ms [33.79 ± 1.49 ms]), and smaller SNRs (log DTL young [old]: 0.79 ± 0.13 [0.71 ± 0.15], log gold cup young [old]: 0.37 ± 0.15 [0.34 ± 0.13]) compared to DTL electrodes. Nevertheless, all mfERG components showed strong significant correlation (r2 ≥ 0.25, p < 0.001) between both electrodes for all eccentricities. Both electrodes allowed for the identification of age-related P1 changes, i.e., P1 amplitude reduction and peak time delay in the older group. There was a trend to higher AUC for the DTL electrode (e.g., averaged P1 amplitude AUC DTL [gold cup] = 0.78 ± 0.07 [0.69 ± 0.09]) to delineate these differences between age groups which, however, failed to reach statistical significance (e.g., p = 0.219 for averaged P1 amplitude).
Conclusions: Both electrode types allow successful mfERG recordings. However, in compliant patients, the use of the DTL electrode appears preferable due to the larger amplitudes, higher SNR, and its better reflection of physiological changes, i.e., age effects. Nevertheless, skin electrodes appear a viable alternative for mfERG recordings. This might be of importance in patients who might not tolerate corneal electrodes such as children and disabled patients.
 Hoffmann MB, Bach M, Kondo M, Li S, Walker S, Holopigian K, Viswanathan S, RobsonAG (2021) ISCEV standard for clinical multifocal electroretinography (mfERG) (2021 update) Documenta Ophthalmologica 142:5–16.
P1 21 Visual electrophysiology phenotype in children with BBS1 mutation causing Bardet-Biedl Syndrome (BBS)
Ajeeta Patel1, Elizabeth Forsythe2, Sian E. Handley1,2, Robert Henderson2,3, William Moore3, Oliver R. Marmoy1,2, Dorothy A. Thompson1,2
1Tony Kriss Visual Electrophysiology Unit, Great Ormond Street Hospital for Children, London, United Kingdom. 2UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom. 3Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, United Kingdom
Purpose To elaborate on the natural history of retinal phenotype in children with BBS1 mutations in anticipation of forthcoming gene therapy.
Methods A retrospective case note review of children with confirmed BBS1 mutation who underwent visual electrodiagnostic testing (EDT) at a single specialist centre, Great Ormond Street Hospital (GOSH), UK, from May 2009 to January 2020 was carried out. Genotype, age, medical history, skin ERG, and pattern reversal VEP (prVEP) data were collated. Specifically, prVEP P100 amplitudes and peak times produced by 98% contrast black and white checks presented in a 30° field with check widths 100′, 50′ and 25′ mins of arc were documented alongside flash ERG a- and b-wave amplitudes and peak-times produced to a published alternative GOSH-ERG protocol. These data were compared to laboratory reference ranges.
Results Of 28 patients with pathogenic variants in BBS1, 16 had Met390Arg homozygous variants and 10 were compound heterozygous with one Met390Arg. Two unrelated children were homozygous for truncating mutation of p.Asp145Glyfs*21. Age of BBS diagnosis ranged from 1 month to 9 years for the Met390Arg homozygotes, with 3/16 investigated for BBS having retinopathy as a primary presenting feature (mean age 8.3 years). BBS investigation was later for compound heterozygotes (1–14 years) and 7/10 had established retinal dysfunction at diagnosis (mean age 8.7 years). Age at first EDT was comparable for Met390Arg homozygotes (range 0.1–13.4 years, median 8.2 years) and compound heterozygotes (0.9–15.1 years, median 7 years). Children with compound heterozygous mutations had more severe retinal dysfunction compared to Met390Arg homozygotes of similar age. Flash ERGs were absent to all stimuli from 9/10 compound heterozygotes at a mean age of 7 years, with the youngest aged 3 years. In contrast only 3/16 of the Met390Arg homozygotes had absent ERGs, mean age 9 years, youngest 8 years. Met390Arg homozygotes with measurable flash ERG showed an array of retinal function: normal responses (n = 6), rod-cone dysfunction (n = 5), and cone-rod dysfunction (n = 2). With increasing age progression of retinal dysfunction correlated strongest with a decrease in rod b-wave amplitude, seconded by increasing cone b-wave peak time. The two children with homozygous p.Asp145Glyfs*21 mutations had no detectable skin ERGs at EDT presentation (aged 11 and 16 years) with some pattern VEP evidence of central field preservation. Spearman’s rank correlation coefficient showed a positive association within Met390Arg compound heterozygotes for increased P100 peak time with increasing age to 100′, 50′, and 25′ check widths (rs 0.87, rs 0.73 and rs 0.75, respectively). This was less apparent for Met390Arg homozygotes (rs 0.38 for 100′ check width), with time to peak for the 50′ and 25′ checks within reference range up to and including the eldest patient aged 17 years.
Conclusions Most children with Met390Arg homozygous mutations undergo BBS1 associated retinopathy later compared to compound heterozygotes but may be younger when referred for BBS investigation due to other presenting features. Retinal change is most likely to manifest after age 5 years in these children as rod-cone dysfunction as is often cited, but can present as cone-rod dysfunction, with the likelihood for preservation of central macular function in the first two decades of life.
P1 23 Electroretinographic evaluation with skin electrodes in eyes with intraocular lymphoma
Jun Makita, Yuji Yoshikawa, Tomoyuki Kumagai, Yuro Igawa, Shunichiro Takano, Takeshi Katsumoto, Takuhei Shoji, Masayuki Shibuya, Kei Shinoda
Department of Ophthalmology, Saitama Medical Univercity, Iruma-Gun, Japan
Purpose To evaluate retinal function in eyes with intraocular lymphoma using skin electrodes.
Methods The ERG components in 11 eyes of 11 cases (male 4, female 7) aged between 38 and 88 years (mean ± SD, 69.4 ± 11.5) diagnosed with intraocular lymphoma from December 1, 2016, to May 30, 2022 at Saitama Medical University Hospital were reviewed.
Results Visual acuity ranged from hand movement to logMAR 1.2 (median 0.2). Cell cytology for the vitreous specimen showed class II in 2 eyes, class III in 6 eyes, class IV in 2 eyes, and class V in 1 eye. Immunoglobulin heavy chain (IgH) gene rearrangement was positive in 3 eyes. The severe attenuation of the ERG waveform amplitudes was found in 6 of 11 eyes (54.5%) in the dark adapted (DA) 0.01 b-wave, in 45.5% in the DA 3.0 a-wave, in 36.4% of the DA 3.0 b-wave, in 36.4% of the light-adapted (LA) 3.0 a-wave, in 18.2% of the LA 3.0 b-wave, and in 36.4% of the 30 Hz flicker response. No eyes showed negative shape (b/a ratio < 1.0) in DA 3.0 ERG. The DA 0.01 ERG was likely to be predominantly impaired. In the DA 3.0 and LA 3.0 ERGs, the a-wave tended to be equally or more severely altered compared to the b-wave.
Conclusions The ERG shows various changes in eyes with intraocular lymphoma which may suggest relatively severe dysfunction in the outer retinal layer.
P1 25 Phenotypical variation with age in CERKL gene-related retinitis pigmentosa in a single family
Deepika C. Parameswarappa
LV Prasad Eye Institute, Hyderabad, India
Purpose To describe the phenotype and genotype correlation of CERKL (Ceramide kinase-like protein) gene mutation-related autosomal recessive retinitis pigmentosa in four members of the same family.
Methods Four patients with autosomal recessive retinitis pigmentosa (RP) from a single family were examined. The retinal phenotypical features were correlated with CERKL gene variant changes within the family.
Results The family consisted of two sisters (39-year-old and 42-year-old) affected with autosomal recessive RP and their two male children (10-year-old son of the 39-year-old mother and 12-year-old son of the 42-year-old mother) affected with autosomal recessive RP. The children were born out of non-consanguineous marriage. The genotypical confirmation was performed in the whole blood sample by targeted next-generation sequencing using Illumina chemistry. All the four affected members showed recessive (homozygous) frameshift deletion at exon 7 of CERKL. All four of them had central vision problems in childhood. The best-corrected visual acuity of the male children was 20/30 to 20/80 and both mothers were able to perceive only hand movements at the time of examination. The common phenotypical features in the affected sons at the younger age were minimal optic disc pallor, minimal arteriolar attenuation, early loss of macular photoreceptors, visual field showing central scotomas, and a severely affected near extinguished full-field electroretinogram. There were no pigmentary or chorioretinal atrophic changes in the retina noted in the children. The common phenotypical features in the affected mothers in the later part of life were prominent vascular attenuation, optic disc pallor, total macular atrophy, peripheral bony spicule pigmentation, peripheral scalloped chorioretinal atrophic patches, and an extinguished full-field electroretinogram.
Conclusions CERKL gene-related RP shows a wide spectrum of phenotypical changes in various age groups. The phenotypical features vary from early macular involvement and no typical retinal pigmentary abnormalities like RP in the first decade of life to severe macular atrophy and typical retinitis pigmentosa changes in the later part of life. The above family highlights the evolving phenotypical characteristics of CERKL gene-related RP over different age groups. The knowledge of changing phenotypes due to CERKL gene from early to later part of life helps in the appropriate diagnosis during younger age and provides guidance for future prognosis.
P1 27 Full field electroretinogram in ocular siderosis
Deepika C. Parameswarappa
LV Prasad Eye Institute, Hyderabad, India
Purpose To describe the full-field electroretinogram findings in 15 eyes of ocular siderosis from a tertiary eye care centre.
Methods Fifteen eyes of ocular siderosis were included in the study. The full-field electroretinogram (ffERG) was performed with the Metrovision system as per standard ISCEV protocol. The study was conducted at a tertiary referral eye care centre and was approved by the institutional review board. ffERG responses were analysed as isolated rod specific, mixed rod-cone, oscillatory potentials (OPs), single flash cone, and cone flicker responses.
Results All 15 eyes had an abnormal ffERG. 53% (8/15) of the eyes had severely affected ERG with extinguished rod specific, mixed rod-cone, OPs, and single flash cone responses. All 8 eyes with severely affected ERG had affected cone flicker responses as well. Of the 15 eyes, isolated rod-specific ERG responses were extinguished in 60% (9/15) and were subnormal in 33% (5/15). The mixed rod-cone ERG responses were extinguished in 53% (8/15) and were subnormal in 40% (6/15). The OPs responses were extinguished in 60% (9/15) of the eyes and were subnormal in 20% (3/15) of the eyes. The single flash cone ERG responses were extinguished in 53% (8/15) and were subnormal in 40% (6/15). Most of the eyes (12/15, 80%) had affected cone flicker ERG responses. 27% (4/15) of eyes with available ffERG had undergone vitreoretinal surgery for removal of an intraocular foreign body; all of these eyes had an extinguished ERG response with affected flicker responses.
Conclusions Our ffERG findings in ocular siderosis show that both rod and cone-specific responses will be affected in ocular siderosis. It also highlights that inner, as well as outer, retinal cells are affected in ocular siderosis.
P1 29 Evidence of both optic nerve and inner retinal dysfunction in patients with neuromyelitis optica
Anisah Kalam1, Anne L. Georgiou1, Magella M. Neveu1,2, Antonio Calcagni1,2, Neringa Jurkute1,2, Anthony G. Robson1,2
1Moorfields Eye Hospital, London, United Kingdom. 2UCL Institute of Ophthalmology, London, United Kingdom
Purpose Neuromyelitis optica (NMO; Devic’s Disease) is a demyelinating autoimmune disorder, associated with serum auto-antibodies to aquaporin-4 (AQP4). AQP4 is an astrocyte water channel protein; thus, AQP4-antibodies lead to an autoimmune inflammatory process targeting optic nerves and spinal cord astrocytes. This study describes the electrophysiological findings in 4 NMO cases.
Methods Four patients with AQP4 auto-antibodies and clinical signs of NMO and were ascertained. All underwent ISCEV-standard pattern reversal and flash VEP (PVEP; FVEP) and pattern and full-field ERG (PERG; ERG) testing. Two patients had comprehensive serial assessments over a 5-year period.
Results Baseline PVEPs were abnormal in 3 subjects, with peak time delay in 4 eyes and moderate to severe amplitude attenuation in 3 eyes. In one patient, the baseline PVEPs were within the reference range bilaterally. Flash VEPs were subnormal without delay in 3 of 8 eyes. The PERG N95:P50 ratio was reduced in all 3 subjects with an abnormal PVEP and there was additional shortening of P50 peak time in 2 of these cases. Full-field ERGs revealed DA 0.01 peak times that were delayed (N = 4 eyes), of borderline timing (n = 2 eyes), or within the reference range (2 eyes of 1 patient). The DA 10 ERG b-wave peak times showed borderline delay (95th percentile) in 2 eyes of 1 patient and a significant delay in 4 eyes of 2 other patients, including one with waveforms resembling an electronegative ERG bilaterally. At five years follow-up, one patient with severely subnormal PVEPs at baseline showed partial amplitude recovery bilaterally but developed asymmetrical PVEP delays (by 7 ms and 37 ms); another patient, who at baseline had unilateral PVEP delay (by 22 ms), N95:P50 ratio reduction, and bilaterally abnormal DA0.01 and DA10 ERG b-waves showed response stability.
Conclusions A range of PVEP and PERG abnormalities were seen in patients with NMO, including evidence suggesting demyelination or evolving optic nerve conduction delay, with or without evidence of retinal ganglion cell involvement. Additional subtle to marked inner retinal dysfunction may be a common feature in NMO patients, but further studies are required to investigate the cause and better understand the pathogenesis and possible effect of AQP4 auto-antibodies on retinal function.
P1 31 Macular function after pneumatic vitreolysis
Louis Philippe Dormegnie1, Sophie Gruchociak2, Carl F. Arndt1
1Reims University Hospital, Reims, France. 2Pole Ophtalmologique de Champagne, Bezannes, France
Purpose: Recently gas injections have been reported in symptomatic vitreomacular traction (VMT). The consequences of pneumatic posterior vitreous detachment (PVD) on macular function have never been evaluated. We assessed the mfERG changes in patients undergoing pneumatic vitreolysis with perfluoropropane (C3F8) for symptomatic VMT.
Methods: The charts of patients undergoing 0.3 ml C3F8 gas injection for symptomatic VMT between January 1, 2021 and December 31, 2021 were examined in this study. The following parameters were noted before and 3 months after gas injection: best-corrected visual acuity, maximal horizontal vitreomacular adhesion, maximal foveal thickness (MFT) as determined with spectral domain optical coherence tomography, and mfERG parameters (N1, P1 amplitudes and implicit times).
Results: 45 eyes of 41 patients with symptomatic VMT had been treated in the predefined time frame. In five eyes, the mfERG had been recorded before and 3 months after gas injection. At 3 months, a significant change of MFT (p = 0.008) was observed. In the mfERG, no statistically significant changes in N1/P1 parameters (amplitude, implicit time) were found.
Conclusions: After pneumatic posterior vitreous detachment, despite improved thickness parameters on OCT, no significant electrophysiological changes were found. The mfERG recordings in a larger group of gas injected patients is necessary to confirm the stability of macular function after pneumatic PVD.
P1 33 Need for two types of visual stimulator for recording the VEP in patients with anti-seizure treatment
Seyed Mohammad Masoud Shushtarian
Department of Biophysics and Biochemistry, Faculty of Advance Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Islamic Republic of Iran
Purpose The type of visual stimulation (flash or pattern reversal) is an important part of the electrophysiological testing when recording visual evoked potentials (VEPs) in patients with different pathological conditions.
Patients suffering from epilepsy and seizures and using anti-seizure medications may need to be tested using VEPs. The aim of this study was to look for the most suitable visual stimulation for recording the VEPs in patients taking anti-seizures medications.
Methods Twenty patients (10 male and 10 female) in the age range of 15–30 years were selected for the purpose of this study. The visual acuity of the patients was sufficient to distinguish the fixation point on the monitor. The patients were all under anti-seizure treatment with medications. VEPs using two types of stimulation (pattern reversal checkerboard and flash) were tested. The VEPs obtained were compared to establish a suitable VEP recording protocol.
Results Latency of the pattern reversal VEP, P100 peak was delayed and there was a decrease in the amplitude of VEP P100 considering the two types of stimulations.
Conclusions In the case of the patients using anti-seizure drugs, both types of stimulators, pattern reversal checkerboard and flash, are necessary to record the VEP and reach a suitable result necessary for clinical purposes.