Doc Ophthalmol [JOURNAL]
Sun
200 papers
Bilateral retinal astrocytic hamartomas in retinitis pigmentosa: two case reports and systematic review.
Zhai RY, Duan C, Zong Y … +3 more , Chang Q, Xu GZ, Gao FJ
Doc Ophthalmol · 2026 May · PMID 42133270 · Publisher ↗
PURPOSE: To report two novel cases of retinitis pigmentosa (RP) associated with bilateral retinal astrocytic hamartomas (RAHs) and to conduct a systematic review of this rare association. DESIGN: Retrospective observatio...
PURPOSE: To report two novel cases of retinitis pigmentosa (RP) associated with bilateral retinal astrocytic hamartomas (RAHs) and to conduct a systematic review of this rare association. DESIGN: Retrospective observational case series and literature review. METHODS: We describe the clinical, multimodal imaging, and genetic findings of two male patients with genetically confirmed RP (RP2 and CDH23 mutations) and bilateral peripapillary RAHs. A comprehensive review of all previously reported cases of RP with RAH was performed to summarize demographic, clinical, and imaging characteristics. RESULTS: Both patients presented with advanced RP and characteristic mulberry-like, calcified lesions at the optic disc margins. Optical coherence tomography angiography (OCTA) demonstrated intrinsic vascularization within the lesions, a key feature distinguishing RAH from optic disc drusen. Systemic and genetic evaluations ruled out phakomatoses. Literature review identified 10 prior cases. Analysis of all 12 cases (including ours) revealed a strong male predominance (10:2), with RAHs typically being bilateral (9/12), peripapillary (11/12), and often multifocal (9/12). Follow-up data showed lesion progression in half of the cases. Genetic heterogeneity was noted, with our cases expanding the mutational spectrum to include RP2 and CDH23. CONCLUSIONS: RAH is a rare but important finding in RP, most commonly presenting as bilateral, peripapillary lesions in male patients. Multimodal imaging, particularly OCTA confirmation of intralesional flow, is crucial for accurate diagnosis and differentiation from drusen. Recognition of this association can prevent misdiagnosis and guide appropriate long-term monitoring for potential lesion progression.
Visual evoked potential abnormalities in spinocerebellar ataxia type 27B: a case report.
Skacik P, Sivak S, Grofik M … +1 more , Kurca E
Doc Ophthalmol · 2026 May · PMID 42113379 · Publisher ↗
INTRODUCTION: Spinocerebellar ataxia type 27B (SCA27B) is an autosomal dominant late-onset cerebellar ataxia caused by a pathogenic GAA repeat expansion in the FGF14 gene. Although oculomotor abnormalities, particularly...
INTRODUCTION: Spinocerebellar ataxia type 27B (SCA27B) is an autosomal dominant late-onset cerebellar ataxia caused by a pathogenic GAA repeat expansion in the FGF14 gene. Although oculomotor abnormalities, particularly downbeat nystagmus, are well recognized, afferent visual pathway involvement has not been systematically investigated. CASE PRESENTATION: We report a 67-year-old man with genetically confirmed SCA27B who presented with a two-year history of progressive cerebellar and somatosensory ataxia, with a Scale for the Assessment and Rating of Ataxia (SARA) score of 13. Neurological examination revealed typical oculomotor abnormalities, including downbeat nystagmus elicited during head-shaking testing. Brain MRI showed mild cerebellar atrophy. Electrophysiological studies demonstrated axonal sensory polyneuropathy and prolonged central conduction times on somatosensory evoked potentials. Comprehensive ophthalmological examination, including optical coherence tomography, showed no structural abnormalities. Pattern-reversal visual evoked potentials, recorded according to ISCEV standards, demonstrated mild bilateral prolongation of P100 latency, measuring 116 ms in the left eye and 115 ms in the right eye, with preserved amplitudes. Compared with laboratory normative data from individuals aged 60-70 years, these values exceeded the upper age-related reference limit. CONCLUSION: This case suggests possible subclinical functional involvement of the post-retinal afferent visual pathways in SCA27B. However, the findings should be interpreted cautiously and confirmed in larger, age-matched cohorts.
Intra- and inter-examiner reliability of ERGs recorded with two types of skin electrodes.
Nagashima R, Kato K, Mizumoto K … +7 more , Mori S, Kurose D, Fujimoto I, Matsubara H, Kudo H, McCulloch DL, Kondo M
Doc Ophthalmol · 2026 May · PMID 42101571 · Publisher ↗
PURPOSE: To determine whether the intra-examiner and the inter-examiner reliabilities of the implicit times and amplitudes of the ERGs differed when recorded with two different types of skin electrodes. SUBJECTS AND METH...
PURPOSE: To determine whether the intra-examiner and the inter-examiner reliabilities of the implicit times and amplitudes of the ERGs differed when recorded with two different types of skin electrodes. SUBJECTS AND METHODS: Eleven subjects (5 men and 6 women) were studied. The RETeval system was used to record ERGs, and the Sensor Strip of the RETeval system or the Red Dot electrocardiography electrodes (Red Dot) were used to record the ERGs. Flicker ERGs were recorded with a natural pupil. To test the intra-examiner reliability, one examiner positioned electrodes and recorded the ERGs three times on three different days from each subject. For the inter-examiner reliability, three different examiners recorded the ERGs from the 11 subjects. The implicit times and amplitudes of the flicker ERGs were analyzed using one-way intraclass correlation coefficients (ICC (1,1)) to assess intra-examiner variability and using a two-way intraclass correlation coefficient (ICC (2,1)) for inter-examiner variability. RESULTS: For implicit times both the ICC (1,1) and ICC (2,1) were > 0.8 for both electrode types. For the amplitude, ICC (1,1) was > 0.8 for both electrodes, but the ICC (2,1) was lower at 0.474 for the Sensor Strip and 0.672 for the Red Dot electrodes. After Benjamini-Hochberg adjustments, the amplitudes did not differ between electrodes in either setting; implicit time was slightly shorter with the Red Dot than with Sensor Strip in the three-examiner setting (BH-adjusted P = 0.032; mean difference, 0.13 ms). CONCLUSION: The intra-examiner reliability was high for both types of electrodes, but the inter-examiner reliability indicated that the amplitudes of the ERGs tended to be less reliable for both types of electrodes. We conclude that standardizing the electrode placement and ensuring precise applications may help improve inter-examiner reproducibility, especially for the amplitude measurements.
New genetic feature associated with fundus albipunctatus: case series of two Spanish children with LRAT gene mutation.
Baldaquí-Baeza A, Díaz-Cascajosa J, Yubero-Siles D … +6 more , Escribano-Serrano G, Salinas-Chaparro D, Aguilera C, Esteve-Garcia A, Alonso-Colmenero I, Català-Mora J
Doc Ophthalmol · 2026 May · PMID 42065837 · Publisher ↗
OBJECTIVE: To describe the genetic mutation and its action mechanism in patients with compatible diagnosis of fundus albipunctatus (FAP). SUBJECTS AND METHODS: We describe the clinical evolution and genetic findings of t...
OBJECTIVE: To describe the genetic mutation and its action mechanism in patients with compatible diagnosis of fundus albipunctatus (FAP). SUBJECTS AND METHODS: We describe the clinical evolution and genetic findings of two female Spanish children of 14 and 16 years old who have been followed at the children's hospital Sant Joan de Déu (Barcelona, Spain). Nyctalopia without detectable field constriction was the initial symptom. Retinal fundus was compatible with FAP or retinitis punctata albescens (RPA). We have registered ophthalmological examination from each visit, including visual acuity, visual field assessment, wide-field fundoscopy imaging, fundus autofluorescence and optical coherence tomography. Full-field electroretinogram (ERG) was also performed. DNA sampling was analysed by next-generation sequency (NGS). RESULTS: Compound heterozygous pathogenic variants in the LRAT gene were identified in both children. Interestingly, these were the same two pathogenic variants, despite the families being unrelated. No additional genetic alterations were found that could explain the disease in our patients. CONCLUSIONS: To the best of our knowledge, up to the present time, only a single clinical case involving a genetic variant in the LRAT gene leading to an FAP phenotype has been reported in the literature. LRAT genetic variants, despite their low frequency in clinical practice, seem to lead to a FAP-like phenotype, in addition to their established association with Leber congenital amaurosis (LCA) and Early Onset Severe Retinal Dystrophy (EOSRD).
The long-term impact of retinopathy of prematurity on retinal function assessed with new patterns of mfERG analysis.
Youn YE, Dorfman AL, Polosa A … +6 more , Hamel P, Luu TM, Nuyt AM, Chemtob S, Ali SK, Qian CX
Doc Ophthalmol · 2026 Jun · PMID 42053862 · Publisher ↗
PURPOSE: To assess the long-term impact of retinopathy of prematurity (ROP) on macular function in pediatric and adult patient cohorts through the analysis of multifocal ERG (mfERG) results. Sectoral analyses were employ...
PURPOSE: To assess the long-term impact of retinopathy of prematurity (ROP) on macular function in pediatric and adult patient cohorts through the analysis of multifocal ERG (mfERG) results. Sectoral analyses were employed to uncover subtle localized findings that ring assessments could mask. METHODS: 25 children and 28 adults were recruited into three groups: "ex-ROP" (individuals with a history of ROP), "preterm" (preterm-born without ROP), and "term" (term-born controls). mfERG P1 amplitudes and latencies were evaluated in five concentric rings centered on the fovea, as well as superior, inferior, nasal and temporal quadrants following Patterns 1, 2 and 3 for sectoral analysis. Macular optical coherence tomography (OCT) was performed to measure central retinal thickness and evaluate correlation with mfERG results. RESULTS: Using a sectoral mfERG analysis approach, applied for the first time in this population, we identified functional alterations that were not apparent with traditional global ring averages. In the pediatric cohort, sectoral evaluation revealed a significant reduction in temporal inner retinal responses in both ex-ROP and preterm children, changes that were obscured when relying solely on traditional mfERG ring analysis. Within the ex-ROP pediatric group, laser-treated eyes showed more pronounced dysfunction, with significantly prolonged P1 latencies and increased central retinal thickness compared to untreated eyes. In adults, sectoral analysis again highlighted functional abnormalities: ex-ROP and preterm participants demonstrated significantly decreased P1 amplitudes in multiple localized regions, including Rings 2 and 3. Finally, both pediatric and adult ex-ROP cohorts exhibited greater central retinal thickness than term-born controls, reinforcing the structural-functional relationship captured more sensitively through this refined sectoral method. CONCLUSION: Our study demonstrated that a history of ROP is associated with diminished macular function, as evidenced by mfERG assessments, a finding more pronounced in adults compared to the younger pediatric cohort, possibly suggestive of an age-related degeneration in retinal function.
A novel IDS variant associated with an isolated ocular phenotype in Hunter syndrome.
Yeh TC, Velez G, Lee SH … +7 more , Ngo GH, Kumar A, Al-Moujahed A, Yu C, Leung LS, Mruthyunjaya P, Mahajan VB
Doc Ophthalmol · 2026 Apr · PMID 42033570 · Publisher ↗
INTRODUCTION: Hunter syndrome (mucopolysaccharidosis type II, MPS II) is an X-linked lysosomal storage disorder caused by iduronate-2-sulfatase (IDS) mutations and is classically associated with multiple-organ-systems in...
INTRODUCTION: Hunter syndrome (mucopolysaccharidosis type II, MPS II) is an X-linked lysosomal storage disorder caused by iduronate-2-sulfatase (IDS) mutations and is classically associated with multiple-organ-systems involvement. Ocular findings are usually reported in conjunction with systemic manifestations, and isolated ocular presentations have not been well characterized. Here, we report a novel hemizygous IDS variant in a patient who initially presented with isolated corneal and retinal pathology and was subsequently diagnosed with attenuated Hunter syndrome. METHODS: Comprehensive ophthalmic and retinal evaluation was performed, including multimodal retinal imaging and full-field electroretinography, alongside genetic testing. RESULTS: A 44-year-old male with progressive nyctalopia demonstrated bilateral parafoveal and peripheral retinal depigmentation with central macular sparing on optical coherence tomography and a symmetric bull's-eye pattern on fundus autofluorescence. Visual field testing revealed bilateral ring scotomas, and full-field electroretinography showed subnormal rod-predominant responses. Pedigree analysis suggested X-linked inheritance. Genetic testing identified a novel hemizygous IDS variant (c.707A > G, p.Lys236Arg), and the diagnosis of Hunter syndrome was supported by markedly reduced IDS activity and elevated urinary glycosaminoglycans with increased heparan sulfate. CONCLUSION: A novel missense IDS mutation was identified in association with Hunter syndrome, highlighting the importance for ophthalmologists to consider MPS II in patients presenting with isolated retinopathy and the value of genetic diagnosis in revealing atypical systemic disease.
The effect of physiological changes in estradiol hormone during the follicular phase of the menstrual cycle in healthy women on retinal ganglion cell function, retinal and optic nerve vascularization and structure.
Hamurcu M, Gültekin BP, Göçmen M … +2 more , Mendi ZN, Kurdoğlu Z
Doc Ophthalmol · 2026 Apr · PMID 42033569 · Publisher ↗
PURPOSE: This study aimed to investigate the effects of estradiol changes occurring during the early follicular phase of the menstrual cycle on retinal ganglion cell function, retinal and optic nerve vascularity and stru...
PURPOSE: This study aimed to investigate the effects of estradiol changes occurring during the early follicular phase of the menstrual cycle on retinal ganglion cell function, retinal and optic nerve vascularity and structure in healthy adults using pattern electroretinography (PERG), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA). METHODS: The study included 26 healthy subjects with a visual acuity of 1.0. Serum hormone levels, intraocular pressure (IOP), cycloplegic spherical equivalent (SE), PERG, retinal nerve fiber layer (RNFL) thickness and OCTA measurements were evaluated. PERG tests were performed using the Metrovision Monpack system. Spectral-domain OCT (Topcon Corporation, Tokyo, Japan); OCTA (Optovue, Inc, Fremont, CA) devices were used. All tests were conducted on the 1st and 14th days of the menstrual cycle, and the results were compared. RESULTS: The mean serum estradiol values on days 1 and 14 were 51 ± 19 ng/L and 304 ± 50 ng/L, respectively. PERG revealed no statistically significant differences in the amplitude or latency of the P50 and N95 waves between days 1 and 14. RNFL thickness did not differ significantly in the mean, superior, or inferior quadrants (p = 0.90, p = 0.85, and p = 0.39, respectively). OCTA analysis showed that peripapillary and macular vascular density values were similar between days 1 and 14 (p > 0.05). Correlation analysis revealed no significant relationship between electrophysiological parameters, RNFL thickness measurements, and retinal vascular densities (p > 0.05). CONCLUSION: In healthy women, no significant functional, vascular, or structural differences were observed in PERG, OCT, or OCTA parameters between low and high estradiol levels on days 1 and 14 of the menstrual cycle. Unlike the persistently low estradiol levels seen in menopause, physiological estradiol fluctuations during a healthy menstrual cycle do not cause functional, structural, or vascular changes in the optic nerve or retina.
Review of the clinical electrooculogram - Part 1: Mechanism of the Light-Rise.
Constable PA, Loh L, Habjan MŠ … +1 more , Padhy SK
Doc Ophthalmol · 2026 Jun · PMID 41986808 · Full text
The clinical electrooculogram (EOG) is the sole clinical electrophysiological test for assessing the function of the retinal pigment epithelium (RPE). However, despite several lines of investigation, the complete mechani...
The clinical electrooculogram (EOG) is the sole clinical electrophysiological test for assessing the function of the retinal pigment epithelium (RPE). However, despite several lines of investigation, the complete mechanism of the response has evaded a comprehensive description. The standard model implicates the rod photoreceptors and a signaling molecule termed the 'light-rise substance' that binds to an apical membrane 'light-rise receptor' or is transported across the membrane to elevate intracellular calcium concentration. The identity of the calcium activated chloride channel in the basolateral membrane was thought to be bestrophin, given the association of mutations in the hbest1 gene with Best Vitelliform Macular Dystrophy. However, recent findings have implicated a member of the anoctamin family as the calcium activated chloride channel with bestrophin regulating intracellular calcium in conjunction with the L-type calcium channel. How the changes in intracellular calcium are manifested as well as how the interaction with light in the dark-adapted state gives rise to the slow-dark and -light damped oscillations are yet to be described fully. This review summarizes the cellular mechanisms of the RPE that have been implicated in the generation of the light-rise and describes the likely candidates for the light-rise substance. A companion paper provides a summary of the bestrophinopathies and possible clinical modifications to enhance the EOG's clinical utility.
Autosomal dominant Riggs-type congenital stationary night blindness with fundus sheen and retinal atrophy due to a novel GNAT1 p.Gln200Arg variant.
Chou JJ, Heath Jeffery RC, Thompson JA … +5 more , McLenachan S, Chelva ES, Lamey TM, McLaren TL, Chen FK
Doc Ophthalmol · 2026 Jun · PMID 41954843 · Full text
PURPOSE: To report an Australian family with congenital stationary night blindness (CSNB, OMIM#139,330) harbouring a novel GNAT1 c.599A > G (p.Gln200Arg) variant. In contrast to previous case reports we observed a fundus...
PURPOSE: To report an Australian family with congenital stationary night blindness (CSNB, OMIM#139,330) harbouring a novel GNAT1 c.599A > G (p.Gln200Arg) variant. In contrast to previous case reports we observed a fundus sheen, outer retinal changes and electrophysiological features of cone dysfunction in addition to a Riggs-type CSNB. METHODS: Ophthalmic history, clinical examination and multimodal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT) were obtained. Full-field electroretinography (ERG) was conducted according to the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. Genetic testing was performed using a targeted next-generation sequencing panel with familial segregation confirmed by Sanger sequencing. In silico prediction tools and protein structural modelling were used to evaluate the pathogenicity and functional impact of the GNAT1 p.Gln200Arg variant respectively. RESULTS: Our proband, a 21-year-old transgender male, and his 62-year-old mother had a lifelong history of nyctalopia and visual acuity of 6/6 OU. The mother exhibited a golden sheen, sectoral chorioretinal atrophy and bone spicules. In the proband FAF imaging revealed hypoAF inferiorly with an arc of hyperAF whilst his mother had regions of hypoAF associated with outer retinal atrophy. Full-field electroretinography in the proband showed a cone-isolated retina with normal light-adapted responses. The mother had reduced and delayed light-adapted 30 Hz flicker. Both carried the GNAT1 variant NM_000172.4:c.599A > G (p.Gln200Arg). In silico analysis predicted impaired GTPase activity in Arg200 and constitutively active signally after photoactivation. The c.599A > G variant was classified as likely pathogenic. CONCLUSIONS: Our study suggests the GNAT1 p.Gln200Arg variant can manifest as both a Riggs-type CSNB and a rod-cone dystrophy within the same pedigree. This work expands the phenotypic spectrum of GNAT1-associated retinopathy and identifies GNAT1 as another potential cause of a fundus sheen.
The luminance-response function of the photopic negative response (PhNR): analysing different stimulation, recording and measurement approaches.
Marmoy OR, Hodson-Tole E, Thompson DA
Doc Ophthalmol · 2026 Jun · PMID 41944930 · Full text
PURPOSE: The photopic negative response (PhNR) is a measure of generalised retinal ganglion cell function. There has been heterogenous methodology to record this, with varied electrode type, stimulus luminance, temporal...
PURPOSE: The photopic negative response (PhNR) is a measure of generalised retinal ganglion cell function. There has been heterogenous methodology to record this, with varied electrode type, stimulus luminance, temporal frequency and measurement approach. This study aimed to empirically explore these features to identify an optimal PhNR luminance-response protocol which produces the lowest variance and maximal efficiency to guide clinical protocols. METHODS: Twelve healthy participants were recruited (age range 27-51y). Flash ERGs were simultaneously recorded from infraorbital skin and corneal fibre electrodes to a range of red flash stimuli (- 0.3-2.4 log cd.s/m, incremented in 0.3 log units), whilst varying temporal frequency (1-5 Hz), background blue luminance (1, 1.5, 2 log cd/m), and PhNR measurement approach (from baseline or b-wave, as an amplitude or ratio). The luminance-response series data were analysed for changes according to these variables, alongside a calculation of variability. RESULTS: The PhNR luminance-response curves showed few significant differences with increasing temporal frequency, though inter-subject variability was highest for the slowest (1 Hz) and highest flash (5 Hz) stimulation rates. Background luminance reduced the relative sensitivity (K) but not maximal amplitude of the luminance-response curves (V). With skin electrodes the b-PhNR amplitude and b-PhNR ratio showed the lowest levels of variability compared with other measurement approaches or electrodes. CONCLUSION: This study demonstrates that temporal frequency can be increased significantly, optimally at 4 Hz, without compromising the PhNR. PhNR variance is lower with skin electrode recordings and PhNR amplitude measurements from the b-wave compared to corneal fibre electrodes and baseline-PhNR amplitudes.
Does EyeKinetix pupillometry clarify RAPD detection?
Kahrhoff MA, Bassi CJ
Doc Ophthalmol · 2026 Apr · PMID 41920452 · Publisher ↗
PURPOSE: To evaluate variability observed in pupil light response with the EyeKinetix pupillometer in healthy non-dark-adapted individuals. METHODS: We performed objective pupillometry in 440 non-dark-adapted patients wi...
PURPOSE: To evaluate variability observed in pupil light response with the EyeKinetix pupillometer in healthy non-dark-adapted individuals. METHODS: We performed objective pupillometry in 440 non-dark-adapted patients with 20/20 corrected visual acuity, normal visual fields, and no ophthalmic disease who presented for routine exam. EyeKinetix was performed as part of the routine exam screening protocol. Metrics reviewed were RAPDx amplitude scores, latency scores, and quantitative metrics of pupil dynamics measured by the EyeKinetix. Sequential retesting was analyzed for repeatability. Statistical analyses included normality testing, confidence intervals, t-tests, and Intraclass Correlation Coefficient (ICC) calculations for repeated measures. RESULTS: Amplitude and latency scores exhibited significant variability. The mean amplitude score was 0.0249 ± 0.247, with 5% of patients > = 2 standard deviations [> 0.51 log unit (LU)]. Latency scores showed low reliability (ICC = 0.165), whereas amplitude, constriction velocity, and release velocity demonstrated moderate to high reliability (ICC = 0.472-0.966). CONCLUSION: Objective pupillometry without dark adaptation using the EyeKinetix device displays substantial variability and identifies a number of relative afferent pupil defects (RAPDs) in this cohort of healthy patients. These findings indicate that, in healthy populations, reliance on RAPDx scores alone could generate false positives. Establishing robust normative cutoffs and validating them in disease cohorts will be necessary before reliable use as a screener. Further optimization may be necessary for more clinical confidence in a primary care setting.
Measuring electroretinograms in tree shrews with a portable electrophysiology device.
Dhakal R, Sanchez NC, Gawne TJ … +1 more , Khanal S
Doc Ophthalmol · 2026 Mar · PMID 41910689 · Publisher ↗
PURPOSE: The RETeval portable flash electrophysiology device is extensively used for assessing retinal function in humans. However, its utility in measuring electroretinograms in preclinical studies has been less explore...
PURPOSE: The RETeval portable flash electrophysiology device is extensively used for assessing retinal function in humans. However, its utility in measuring electroretinograms in preclinical studies has been less explored. Tree shrews (small diurnal mammals closely related to primates) are a well-established animal model of emmetropization known to exhibit robust responses to visual cues and mimic human juvenile-onset myopia. This study aimed to evaluate the intra- and inter-session repeatability of full-field photopic electroretinograms (ERGs) recorded using the RETeval system in tree shrews. METHODS: At 24 ± 1 days of visual experience (DVE), twelve juvenile tree shrews housed in broadband colony light (100-300 lx) underwent electrophysiology testing of the normally developing eye using the RETeval system (LKC Technologies, MD, USA). Measurements were repeated twice in each session, as well as at 30 and 35 DVE. The amplitudes and peak times of the flash, flicker, photopic negative response, S-cone, and On-Off ERGs were analyzed. The intra- and inter-session repeatability was assessed using the coefficient of variation (CoV), intra-class correlation coefficient (ICC), mean bias (%), paired t-test, and Bland-Altman analysis. RESULTS: Tree shrew ERGs exhibited well-defined and robust waveforms comparable to those of human ERGs. Flash and flicker ERGs showed excellent intra-session repeatability for both amplitudes and peak times (CoV < 5%, mean bias ≤ 5%, and ICC ≥ 0.98). While the ERGs were also repeatable across different sessions, the repeatability metrics were comparatively better for peak times (CoV: < 10%, mean bias: < 15%) than for amplitudes (CoV: 13.36-29.35%, mean bias: 18.89-41.51%) with ICC values between 0.4 and 0.86 for inter-session ERGs, indicating modest repeatability. CONCLUSIONS: The RETeval measurements of full-field photopic ERGs in tree shrews were robust and reliable, with waveforms morphologically similar to human ERGs, demonstrating the utility of the RETeval system in measuring retinal function in this species. The photopic ERGs were repeatable across sessions on different days, indicating the feasibility of using this device in longitudinal studies of retinal function in tree shrews, for example, in studying the neural basis of emmetropization.
Anomalous contrast as an adaptive violation of the Talbot-Plateau law.
Greene E, Morrison J
Doc Ophthalmol · 2026 Mar · PMID 41906035 · Publisher ↗
PURPOSE: To better understand anomalous contrast mechanisms that allow flicker-fused stimuli to be visible even when they provide the same physical contrast as background. METHOD: Stimulus flicker was used to elicit diff...
PURPOSE: To better understand anomalous contrast mechanisms that allow flicker-fused stimuli to be visible even when they provide the same physical contrast as background. METHOD: Stimulus flicker was used to elicit differential activation of ON and OFF retinal channels at frequencies above the flicker-fusion threshold. Providing balanced light energy to ON and OFF channels will normally cause the stimulus to vanish into the background. RESULTS: We used ultrabrief bright pulses, combined with ultralong dark pulses, to elicit "anomalous contrast" that rendered the stimulus visible, even though it had the same average luminance as the background. The duration and intensity of flicker components were varied to gain insight into the conditions that would elicit this effect. CONCLUSIONS: Anomalous contrast displays violated the Talbot-Plateau law, but in doing so, provided an adaptive way to register and signal contours that matched background luminance. These findings contribute additional details about this visual adaptation, and we discuss how the retinal circuitry provides for stimulus visibility.
Correction: ISCEV extended protocol for the photoreceptor directed ERG using full-field silent substitution stimuli.
Kremers J, Barboni MTS, Zele AJ … +7 more , Feigl B, McAnany JJ, Robson AG, Nagy BV, Parry N, Mahroo OA, Huchzermeyer C
Doc Ophthalmol · 2026 Apr · PMID 41886017 · Full text
Abstract loading — click title to view on PubMed.
L- and M-cone-directed Global flash multifocal electroretinogram: conceptualization and development.
Ravi N, Chan HHL
Doc Ophthalmol · 2026 Jun · PMID 41831202 · Full text
BACKGROUND AND PURPOSE: Multifocal Electroretinogram (mfERG) applies a fast flicker-based stimulation on the human retina and is considered a valuable tool in studying the cone photoreceptor functional pathways. At the s...
BACKGROUND AND PURPOSE: Multifocal Electroretinogram (mfERG) applies a fast flicker-based stimulation on the human retina and is considered a valuable tool in studying the cone photoreceptor functional pathways. At the same time, the global flash paradigm of the mfERG (MOFO mfERG) is found to be advantageous in the simultaneous evaluation of retinal responses arising from outer (direct component, DC) and inner (induced component, IC) retinal levels. Incorporating a silent substitution stimulus to the MOFO mfERG remains unexplored yet has broad potential utility. The present study aimed to develop an L- and M-cone directed global flash mfERG. METHODS: A silent substitution stimulus was created appropriate for the commercially available LED monitor. Using the conventional 96% contrast MOFO mfERG as a reference, L- and M-cone directed MOFO mfERG with 19-hexagon stimulation was created and tested in 36 Chinese adults with normal colour vision. Experimental validation was conducted using high-intensity red and green light adaptation to simulate colour vision deficiency. RESULTS: Mathematical validation was performed by calculating and ensuring that proper cone quantal catches are achieved at both targeted and non-targeted cone photoreceptors. The cone response amplitude from participants with simulated protanopia and deuteranopia showed a reduction of up to 50% (p < 0.05) following pigment bleach due to light adaptation. The mean L/M cone amplitude ratio for the Chinese adults concerning the DC and IC was 0.84 ± 0.29 and 0.77 ± 0.32, respectively, for all rings combined. The M-cone amplitudes were higher than that of the L-cone. The M-cone responses were phase-advanced or faster compared to the L-cone responses (p < 0.001). CONCLUSION: The L- and M-cone-directed global flash mfERG protocols may provide valuable details on the specific cone-related outer and inner retinal responses and hold extensive utility in cone-related diseases and the evaluation of colour vision.
Calculation of silent substitution stimuli for full-field electroretinography using the SilentSubstiTutor application.
Huchzermeyer C, Kremers J
Doc Ophthalmol · 2026 Apr · PMID 41831201 · Full text
PURPOSE: The silent substitution technique allows photoreceptor directed stimulation (i.e., the selective stimulation of different photoreceptor types or a specific combination of photoreceptor types). METHODS: Calculati...
PURPOSE: The silent substitution technique allows photoreceptor directed stimulation (i.e., the selective stimulation of different photoreceptor types or a specific combination of photoreceptor types). METHODS: Calculation of these stimuli is not trivial, requiring complex matrix calculations based on specific datasets (spectral power distributions of primary lights, photoreceptor fundamentals, and optical densities of pre-receptoral filters). Several tools have been published that facilitate these calculations, including an excel file and a python library, but these are difficult to use without prior knowledge. RESULTS: We introduce an online application that allows calculation of silent substitution stimuli in a graphical user interface (GUI) for common use-cases (3 to 5 primary lights, periodic stimuli modulated around an average setting of the test field, 10° standard observers). CONCLUSION: The goal is to provide a practical tool that can be used in these cases, but that can also be used as a teaching tool for beginners who plan to use the more sophisticated methods.
Validation of a novel multi-luminance shape discrimination test for assessment of functional vision.
Emanuelli A, Bakall B, Lam BL … +13 more , Wykoff CC, Liao D, Bergstrom L, Vitaliy Z, Carlson M, Kim S, Batabyal S, Chang J, Koester J, Von Tress M, Kosinski M, Barone SB, Mohanty SK
Doc Ophthalmol · 2026 Mar · PMID 41826528 · Publisher ↗
BACKGROUND: In low-vision patients, traditional measures often fall short of capturing functional vision improvements. The study aims to assess the reliability and validity of a novel functional low-vision outcome assess...
BACKGROUND: In low-vision patients, traditional measures often fall short of capturing functional vision improvements. The study aims to assess the reliability and validity of a novel functional low-vision outcome assessment, the Multi-luminance Shape Discrimination Test (MLSDT). METHODS: This is a prospective, observational study in 25 participants with severe vision loss due to retinitis pigmentosa (RP) with visual acuity worse than or equal to LogMAR 1.6, and in 10 normal vision participants. The MLSDT utilizes three differently shaped objects, randomly positioned on pressure sensors, to enable an automated, quantifiable response in a controlled multi-luminance environment. The assessment accuracy (recognizing the correct object and picking it up) was measured using the MLSDT. Convergent validity of MLSDT was evaluated with measures of visual acuity and visual field, as well as patient-reported outcomes. RESULTS: The 35 study participants (60% male and 40% female) had a mean age of 46.5 years old (range: 19-78 years), with 24 Hispanic individuals. Estimates of test-retest reliability for MLSDT exceeded 0.50. The correlations between MLSDT test scores and LogMAR visual acuity were strong (> -0.7). For a difference of 0.3 LogMAR between the groups of RP participants, a decrease of ~ 2-level MLSDT score was observed. Moderate to strong correlations were also observed between MLSDT test scores and the measures of visual field and patient-reported outcome measures. CONCLUSION: Psychometric evaluation demonstrates the reliability and validity of the novel functional vision endpoint, MLSDT. The MLSDT test performance in participants with different visual acuities showed improved object recognition when the luminance level was enhanced.
Anterior segment, static and dynamic pupillography changes in patients using different types of alpha-1 blockers.
Birgul R, Akbay EK, Demirtaş AA … +1 more , Daldal H
Doc Ophthalmol · 2026 Mar · PMID 41801324 · Publisher ↗
AIM: To investigate anterior segment and pupillary changes in patients with BPH (benign prostate hyperplasia) using different types of alpha-1 blockers. MATERIALS AND METHODS: The right eye of male patients using tamsulo...
AIM: To investigate anterior segment and pupillary changes in patients with BPH (benign prostate hyperplasia) using different types of alpha-1 blockers. MATERIALS AND METHODS: The right eye of male patients using tamsulosin, siladosin, alfuzosin or doxazosin, and the right eye of male subjects in the control group were measured in the study. Anterior segment and pupillography measurements were performed using a Scheimpflug imaging technique of Sirius device. Central corneal thickness (CCT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), scotopic, mesopic and photopic pupil sizes and dynamic pupil sizes at 0, 1, 2, 4, 6, 8 and 10 s (s) were measured. RESULTS: Thirty-three patients using tamsulosin, 32 patients using siladosin, 31 patients using alfuzosin and 30 patients using doxazosin were compared with 34 patients in a control group. There was no statistically significant difference between the groups in age, CCT, CV, ACD, ACA, ACV, static pupillography under mesopic and photopic conditions. For three of the groups there was no statistically significant difference from the control group for either scotopic or dynamic pupillography, however pupil size was significantly smaller in the doxazosin group under both static and dynamic conditions. CONCLUSION: The alpha-1 blockers included in this study were those most commonly used in clinical practice. Our results showed that, as aspected, alpha-1 blockers do not change the anterior segment. Three of the groups showed no abnormal pupil behaviour, but the diameter was significantly smaller in the doxazosin group.
Review of the clinical electrooculogram - Part 2: the bestrophinopathies and modified protocols.
Padhy SK, Habjan MŠ, Constable PA
Doc Ophthalmol · 2026 Jun · PMID 41795754 · Full text
The light-rise of the electro-oculogram (EOG) is used as a clinical marker for a collection of disorders known as the 'bestrophinopathies.' This review provides an overview of these conditions including Best Vitelliform...
The light-rise of the electro-oculogram (EOG) is used as a clinical marker for a collection of disorders known as the 'bestrophinopathies.' This review provides an overview of these conditions including Best Vitelliform Macular Dystrophy (BVMD, Autosomal Recessive Bestrophinopathy (ARB), Adult Onset Vitelliform Macular Dystrophy (AVMD) and Autosomal Dominant Vitreoretinalchoriodopathy (ADVIRC) and potential future therapies. One drawback of the EOG is the time to administer the test and shortened protocols that have been developed to improve the clinical testing of the EOG which include incorporating measures during recordings of the ERG or shortening the period of dark and light adaptation. The companion paper summarizes the cellular mechanism of the EOG, and this review is focused on the clinical applications of the EOG.
Beyond the snellen chart: exploring the clinical potential of sweep visual evoked potentials for visual acuity measurement.
Hermas A, Dollin M, Karanjia R … +4 more , Kantungane AL, Nguyen HA, Tsilfidis C, Coupland S
Doc Ophthalmol · 2026 Mar · PMID 41790402 · Publisher ↗
PURPOSE: To evaluate the agreement between Snellen visual acuity (VA) and sweep visual evoked potential (sVEP) VA in individuals with normal vision and assess sVEP variability and reproducibility across multiple test ses...
PURPOSE: To evaluate the agreement between Snellen visual acuity (VA) and sweep visual evoked potential (sVEP) VA in individuals with normal vision and assess sVEP variability and reproducibility across multiple test sessions. METHODS: Thirty-nine healthy participants (78 eyes) underwent Snellen and sVEP VA testing. Ten participants (20 eyes) also underwent sVEP testing twice daily (morning and afternoon) on three separate days (120 total recordings). and Snellen VA measurements showed strong agreement, with a mean absolute difference of 0.03 LogMAR (less than one Snellen line). Forty of 78 eyes had differences within one Snellen line, while the largest discrepancy reached four lines. Statistical analysis (P = 0.201) indicated no significant difference between the two methods. sVEP reproducibility was also high, with no significant variation between morning and afternoon recordings (P = 0.67), confirming its stability as a clinical tool. CONCLUSION: sVEP provides objective and reproducible VA measurements comparable to Snellen VA, suggesting its potential as an alternative clinical assessment tool, particularly for patients with communication challenges, cognitive impairments, or suspected malingering vision loss.
About
- Frequency
- Sun
- Papers found
- 200
- RSS feed
- Subscribe