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Talsma HE, Kruijt CC, de Wit GC, Zwerver SHL, van Genderen MM. Nystagmus Characteristics in Albinism: Unveiling the Link to Foveal Hypoplasia and Visual Acuity. Invest Ophthalmol Vis Sci 2023; 64:30. [PMID: 38133506 PMCID: PMC10746925 DOI: 10.1167/iovs.64.15.30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Purpose The purpose of this study was to describe the association among nystagmus characteristics, foveal hypoplasia, and visual acuity in patients with albinism. Methods We studied nystagmus recordings of 50 patients with albinism. The nystagmus waveform was decomposed into two types: dominantly pendular and dominantly jerk. We correlated the nystagmus type, amplitude, frequency, and percentage of low velocity (PLOV) to Snellen visual acuity and foveal hypoplasia grades. Results The grade of foveal hypoplasia and visual acuity showed a strong correlation (r = 0.87, P < 0.0001). Nystagmus type and PLOV had the strongest significant (P < 0.0001) correlation with visual acuity (r = 0.70 and r = -0.56, respectively) and with foveal hypoplasia (r = 0.76 and r = -0.60, respectively). Patients with pendular nystagmus type had the lowest PLOV, and the highest grade of foveal hypoplasia (P < 0.0001). Severe foveal hypoplasia (grade 4), was almost invariably associated with pendular nystagmus (86%). Conclusions Foveal hypoplasia grade 4 is associated with pendular nystagmus, lower PLOV, and worse visual acuity. Based on these results, nystagmus recordings at a young age may contribute to predicting visual outcomes.
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Affiliation(s)
- Herman E. Talsma
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Charlotte C. Kruijt
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Gerard C. de Wit
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Stefan H. L. Zwerver
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Maria M. van Genderen
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
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Randall D, Fox SL, Fenner JW, Arblaster GE, Bjerre A, Griffiths HJ. Using VR to Investigate the Relationship between Visual Acuity and Severity of Simulated Oscillopsia. Curr Eye Res 2020; 45:1611-1618. [PMID: 32546022 DOI: 10.1080/02713683.2020.1772834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE Oscillopsia is a debilitating symptom resulting from involuntary eye movement most commonly associated with acquired nystagmus. Investigating and documenting the effects of oscillopsia severity on visual acuity (VA) is challenging. This paper aims to further understanding of the effects of oscillopsia using a virtual reality simulation. METHODS Fifteen right-beat horizontal nystagmus waveforms, with different amplitude (1°, 3°, 5°, 8° and 11°) and frequency (1.25 Hz, 2.5 Hz and 5 Hz) combinations, were produced and imported into virtual reality to simulate different severities of oscillopsia. Fifty participants without ocular pathology were recruited to read logMAR charts in virtual reality under stationary conditions (no oscillopsia) and subsequently while experiencing simulated oscillopsia. The change in VA (logMAR) was calculated for each oscillopsia simulation (logMAR VA with oscillopsia - logMAR VA with no oscillopsia), removing the influence of different baseline VAs between participants. A one-tailed paired t-test was used to assess statistical significance in the worsening in VA caused by the oscillopsia simulations. RESULTS VA worsened with each incremental increase in simulated oscillopsia intensity (frequency x amplitude), either by increasing frequency or amplitude, with the exception of statistically insignificant changes at lower intensity simulations. Theoretical understanding predicted a linear relationship between increasing oscillopsia intensity and worsening VA. This was supported by observations at lower intensity simulations but not at higher intensities, with incremental changes in VA gradually levelling off. A potential reason for the difference at higher intensities is the influence of frame rate when using digital simulations in virtual reality. CONCLUSIONS The frequency and amplitude were found to equally affect VA, as predicted. These results not only consolidate the assumption that VA degrades with oscillopsia but also provide quantitative information that relates these changes to amplitude and frequency of oscillopsia.
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Affiliation(s)
- David Randall
- Medical Physics, Infection Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK.,Insigneo Institute for In-silico Medicine, University of Sheffield , Sheffield, UK
| | - Sophie Lauren Fox
- Division of Ophthalmology and Orthoptics, Health Sciences School, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK
| | - John Wesley Fenner
- Medical Physics, Infection Immunity and Cardiovascular Disease, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK.,Insigneo Institute for In-silico Medicine, University of Sheffield , Sheffield, UK
| | - Gemma Elizabeth Arblaster
- Division of Ophthalmology and Orthoptics, Health Sciences School, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK
| | - Anne Bjerre
- Division of Ophthalmology and Orthoptics, Health Sciences School, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK
| | - Helen Jane Griffiths
- Division of Ophthalmology and Orthoptics, Health Sciences School, Faculty of Medicine, Dentistry and Health, University of Sheffield , Sheffield, UK
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Kelly JP, Phillips JO, Weiss AH. The relationship of nystagmus waveform on the VEP response in infantile nystagmus syndrome: a small case series. Doc Ophthalmol 2017; 134:37-44. [PMID: 28054161 DOI: 10.1007/s10633-016-9568-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/14/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE The relationship between eye movements and the visual evoked potential (VEP) response was examined in two subjects with infantile nystagmus syndrome (INS). Changes in VEP amplitude were compared between periods of foveation versus periods of high-frequency nystagmus. An analysis is proposed that improves extraction of the checkerboard reversal VEP signal from subjects with INS. METHODS INS subjects were 2 healthy children (12-13 years old) with 20/40 or better corrected acuity. Optical coherence tomography confirmed the optic nerves, retina, and fovea were within normal variation. VEPs were recorded to checkerboard reversal and to onset/offset of horizontal gratings while simultaneously recording the electrooculogram (EOG). VEP epochs underwent Fourier analysis, and epochs were examined for phase consistency with the mean. Foveation periods were compared to video-oculography recordings from a separate session. RESULTS Optic nerve misrouting, such as crossed VEP asymmetry seen in albinism, or ipsilateral VEP asymmetry seen in achiasma, was not detected in either subject. By averaging only epochs in which EOG epochs showed foveation, VEP amplitude could be increased ≥59%. Averaging the VEP only on epochs with consistent phase at Oz increased VEP amplitude by ≥twofold; subsequent EOG epochs after this analysis mostly contained foveation periods or minimal EOG activity. Latency varied <14 ms across all analyses. CONCLUSIONS The checkerboard reversal VEP signal is dependent on foveation periods in subjects with INS despite good visual acuity. Reduction in VEP amplitude due to retinal image motion induces noise and/or lack of phase locking in the VEP epochs. Selective averaging of epochs based on phase consistency improves the extraction of a VEP signal, likely when retinal image motion is minimized.
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Affiliation(s)
- John P Kelly
- Division of Ophthalmology, Roger H. Johnson Vision Lab, Seattle Children's Hospital, OA.5.345, 4800 Sand Point Way NE, W-4753, Seattle, WA, 98105, USA.
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA, 98105, USA.
| | - James O Phillips
- Division of Ophthalmology, Roger H. Johnson Vision Lab, Seattle Children's Hospital, OA.5.345, 4800 Sand Point Way NE, W-4753, Seattle, WA, 98105, USA
- Department of Otolaryngology, University of Washington School of Medicine, Seattle, WA, 98105, USA
| | - Avery H Weiss
- Division of Ophthalmology, Roger H. Johnson Vision Lab, Seattle Children's Hospital, OA.5.345, 4800 Sand Point Way NE, W-4753, Seattle, WA, 98105, USA
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA, 98105, USA
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Kelly JP, Phillips JO, Weiss AH. VEP analysis methods in children with optic nerve hypoplasia: relationship to visual acuity and optic disc diameter. Doc Ophthalmol 2016; 133:159-169. [PMID: 27882486 DOI: 10.1007/s10633-016-9566-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/15/2016] [Indexed: 11/27/2022]
Abstract
PURPOSE Assessing vision in young children with optic nerve hypoplasia (ONH) is challenging due to multi-directional infantile nystagmus, the range of optic nerve loss, and cognitive delay. This study examined visual evoked potential (VEP) responses and averaging techniques in children with ONH. The assumption is that EEG epochs with inconsistent temporal phase would be associated with nystagmus, signal reduction due to axon loss, and visual inattention. METHODS A retrospective chart review was performed on 44 children (average age 2.2 years; SD 1.9). Optic disc diameter was estimated by ophthalmoscopy. Visual function was measured under binocular viewing and then compared to the eye with the larger optic disc to exclude secondary amblyopia. Visual acuity was measured by Teller cards or by recognition optotypes, and both measures were converted into log minimum angle of resolution (logMAR). VEPs were recorded to onset/offset of horizontal gratings and to reversing checkerboards. Signal-to-noise ratios (SNRs) were estimated from phase consistency across epochs in the Fourier domain. VEPs were also averaged after (1) correction of epochs for phase shifts across a limited bandwidth, or (2) selection of only epochs showing phase consistency. RESULTS Optic disc diameter, logMAR, VEP amplitudes, and VEP SNR were all significantly inter-correlated. Optic disc diameter correlated best with VEP SNR (Spearman rho = 0.82; p < 0.001). Age-corrected logMAR correlated with optic disc diameter and VEP SNR (Spearman rho = -0.695 and 0.70, respectively; p < 0.001). VEP latency poorly correlated with optic disc diameter or logMAR. Correction of phase shifts or selection of epochs based on phase consistency significantly increased VEP amplitude and SNR for children with optic disc diameters <1000 microns. Correction of phase inconsistency did not improve the correlation of VEP parameters with optic disc diameter or with logMAR. CONCLUSIONS In ONH, the size of the optic nerve is correlated with VEP SNR and logMAR. The results imply a direct relationship between the reduction in optic nerve axons and generalized reduction in visual function. Our calculation of VEP SNR provides objective assessment of optic nerve function that is independent of subjective scoring of VEP peaks.
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Affiliation(s)
- John P Kelly
- Division of Ophthalmology, OA.5.345, Roger H. Johnson Vision Lab, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA, 98105, USA. .,Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA, 98105, USA.
| | - James O Phillips
- Division of Ophthalmology, OA.5.345, Roger H. Johnson Vision Lab, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA, 98105, USA.,Department of Otolaryngology, University of Washington School of Medicine, Seattle, WA, USA
| | - Avery H Weiss
- Division of Ophthalmology, OA.5.345, Roger H. Johnson Vision Lab, Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA, 98105, USA.,Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA, 98105, USA
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Abstract
The purpose of this report is to summarize an understanding of the ocular motor system in patients with albinism. Other than the association of vertical eccentric gaze null positions and asymmetric, (a) periodic alternating nystagmus in a large percentage of patients, the ocular motor system in human albinism does not contain unique pathology, rather has "typical" types of infantile ocular oscillations and binocular disorders. Both the ocular motor and afferent visual system are affected to varying degrees in patients with albinism, thus, combined treatment of both systems will maximize visual function.
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Affiliation(s)
- Richard W. Hertle
- The Children's Vision Center, Akron Children's Hospital, Akron, Northeast Ohio Medical Universities, Rootstown, Ohio, United States
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