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Voluntary flutter (sometimes known as “voluntary nystagmus”) is a conjugate saccadic oscillation of the eyes that occurs in some healthy individuals. It has no relation to pathological nystagmus, which can manifest in infancy or become acquired later in life. This report presents an unusual case of voluntary flutter that presented in a 20-year-old male with autism spectrum disorder during ocular examination via direct ophthalmoscopy. Refraction and ocular motor balance were normal, and visual acuity was good in each eye (−0.10 logMAR). During direct ophthalmoscopy, a fine intermittent tremor was initiated. The patient was referred for further assessment, and eye movements were recorded at 1,000 Hz with an EyeLink 1000 eye tracker. Upon request, the patient could manifest voluntary flutter again and sustain the eye movements with effort during convergence. The voluntary flutter consisted of back-to-back saccadic oscillations in a predominantly horizontal direction, with an average frequency of 13 Hz and an amplitude of ∼8°, both reducing over time. We speculate that the discomfort induced by the proximity of the clinician during direct ophthalmoscopy examination may have triggered the eye oscillations. Although the oscillations typically manifest during convergence, atypical forms of voluntary flutter can also occur during divergence. Voluntary flutter can be a useful differential diagnosis in patients with a recently onset apparent “nystagmus,” and no other neurological signs and symptoms.

It is widely recognised that children with Down syndrome have a broad range and a high prevalence of visual deficits and it has been suggested that those with Down syndrome are more likely to exhibit visual perception deficits indicative of cerebral visual impairment. This exploratory study aims to determine the prevalence of behavioural features suggestive of cerebral visual impairment (CVI) occurring with Down syndrome and whether the visual problems can be ascribed to optometric factors. A cohort of 226 families of children with Down syndrome (trisomy 21), aged 4–17, were invited to participate in a validated question inventory, to recognise visual perception issues. The clinical records of the participants were then reviewed retrospectively. A five-question screening instrument was used to indicate suspected CVI. The majority of the 81 families who responded to the questionnaire reported some level of visual perceptual difficulty in their child. Among this cohort, the prevalence of suspected CVI as indicated by the screening questionnaire was 38%. Only ametropia was found to have a significant association with suspected CVI, although this increased the correct prediction of suspected CVI outcome by only a small amount. Results suggest that children with Down syndrome are more likely to experience problems consistent with cerebral visual impairment, and that these may originate from a similar brain dysfunction to that which contributes to high levels of ametropia and failure to emmetropise. It is important that behavioural features of CVI are recognised in children with Down syndrome, further investigations initiated and appropriate management applied.

Our objective was to present the findings of an opt-in, school-based eye care service for children attending 11 special schools in England and use these findings to determine whether a vision screening programme would be appropriate for this population. Data from eye examinations provided to 949 pupils (mean age 10.7 years) was analysed to determine the prevalence and aetiology of visual deficiencies and reported eye care history. For 46.2% (n = 438) of pupils, a visual deficiency was recorded. 12.5% of all the children seen (n = 119) had a visual deficiency that was previously undiagnosed. Referral for a medical opinion was made for 3.1% (n = 29) of pupils seen by the service. Spectacle correction was needed for 31.5% (n = 299) of pupils; for 12.9% (122) these were prescribed for the first time. 3.7% (n = 11) of parents/carers of pupils needing spectacles chose not to use the spectacle dispensing service offered in school. Eye care history was available for 847 pupils (89.3%). Of the pupils for whom an eye care history was available, 44% (n = 373) reported no history of any previous eye care and10.7% (n = 91) reported a history of attending a community optical practice/opticians. Only one pupil from the school entry 4-5 age group (0.6% of age group n = 156) would have passed vision screening using current Public Health England screening guidelines. Children with a diagnosis of autism were significantly less likely to be able to provide a reliable measurement of visual acuity. This study supports previously published evidence of a very high prevalence of visual problems in children with the most complex needs and a significant unmet need in this group. It demonstrates routine school entry vision screening using current Public Health England guidelines is not appropriate for this group of children and very low uptake of community primary eye care services.

Background: Dyslexia, a neurodevelopmental disorder affecting reading skills, poses significant challenges to children's academic performance and quality of life. Despite its rising prevalence and adverse effects, understanding of its relationship with vision anomalies remains limited, particularly in low-resource settings like Nigeria. This study aims to assess the prevalence of binocular vision anomalies (BVAs) among children with and without dyslexia in Kano, Nigeria. Methods: This is a hospital-based, cross-sectional, matched-paired, controlled study conducted at the Aminu Kano Teaching Hospital (AKTH) Eye Clinic in Northern Nigeria. The study included school children who visited the AKTH Eye Clinic from January 2018 to December 2022. Visual acuity tests, external eye examinations and accommodative, binocular vision and oculomotor skills tests were conducted. Descriptive statistics, independent t-tests, Mann–Whitney U tests and Fisher's exact tests were conducted, with a significance level set at p < 0.05. Results: Forty-four children aged 12 ± 2 years participated. Children with dyslexia reported higher rates of visual symptoms than those without dyslexia, Blurring vision, visual distortion and eye strain were the most prevalent (p < 0.05) BV symptoms. Accommodative insufficiency), was the most common visual abnormality, and was significantly higher in children with dyslexia than those without dyslexia (45.5% vs. 18.2%). However, other visual anomalies showed no significant difference between groups. There was a high prevalence of binocular vision anomalies in both groups. Binocular test findings showed dyslexic children had significantly lower distance positive fusional vergence recovery values (p = 0.005). All cases of convergence insufficiency alone were found in the non-dyslexic group. Conclusions: The study found that children with dyslexia residing in Northern Nigeria demonstrated higher rates of visual symptoms, more accommodative insufficiency and lower distance positive fusional vergence recovery values compared to their non-dyslexic counterparts. [ABSTRACT FROM AUTHOR]

Background/aims Recent work has called into question the ability of visual acuity (VA) to accurately represent changes in visual function in infantile nystagmus (IN). This systematic review investigated factors affecting visual performance in IN, to guide development of suitable alternatives to VA. Methods Included studies used an experimental manipulation to assess changes in visual function in people with IN. Interventional studies, case series and case studies were excluded. Six databases were searched in August 2023. Selection, detection, attrition and measurement bias were assessed. Due to heterogeneous methodologies, narrative synthesis was undertaken. Results Eighteen relevant papers were identified, 11 of which complied with the review criteria. Articles were grouped according to the factor manipulated to evoke within-participant changes in performance (motion blur, psychological state, gaze angle or visual crowding). Optotype, image, grating and moving stimuli have been employed under varying lighting conditions and exposure duration. Conclusion Several factors affecting visual performance should be considered when assessing visual function in IN. While maximum VA is a useful metric, its measurement deliberately minimises nystagmus-specific factors such as changes in visual performance with gaze angle and the 'slow to see' phenomenon. Maximum VA can be measured using the null zone, providing unlimited viewing time, reducing stress/mental load and minimising visual crowding. Gaze-dependent functional vision space is a promising measure which quantifies the impact of the null zone but does not consider temporal vision. Although no complete measurement technique has yet been proven, this review provides insights to guide future work towards development of appropriate methods. [ABSTRACT FROM AUTHOR]

Voluntary flutter (sometimes known as "voluntary nystagmus") is a conjugate saccadic oscillation of the eyes that occurs in some healthy individuals. It has no relation to pathological nystagmus, which can manifest in infancy or become acquired later in life. This report presents an unusual case of voluntary flutter that presented in a 20-year-old male with autism spectrum disorder during ocular examination via direct ophthalmoscopy. Refraction and ocular motor balance were normal, and visual acuity was good in each eye (−0.10 logMAR). During direct ophthalmoscopy, a fine intermittent tremor was initiated. The patient was referred for further assessment, and eye movements were recorded at 1,000 Hz with an EyeLink 1000 eye tracker. Upon request, the patient could manifest voluntary flutter again and sustain the eye movements with effort during convergence. The voluntary flutter consisted of back-to-back saccadic oscillations in a predominantly horizontal direction, with an average frequency of 13 Hz and an amplitude of ∼8°, both reducing over time. We speculate that the discomfort induced by the proximity of the clinician during direct ophthalmoscopy examination may have triggered the eye oscillations. Although the oscillations typically manifest during convergence, atypical forms of voluntary flutter can also occur during divergence. Voluntary flutter can be a useful differential diagnosis in patients with a recently onset apparent "nystagmus," and no other neurological signs and symptoms. [ABSTRACT FROM AUTHOR]

It is widely recognised that children with Down syndrome have a broad range and a high prevalence of visual deficits and it has been suggested that those with Down syndrome are more likely to exhibit visual perception deficits indicative of cerebral visual impairment. This exploratory study aims to determine the prevalence of behavioural features suggestive of cerebral visual impairment (CVI) occurring with Down syndrome and whether the visual problems can be ascribed to optometric factors. A cohort of 226 families of children with Down syndrome (trisomy 21), aged 4–17, were invited to participate in a validated question inventory, to recognise visual perception issues. The clinical records of the participants were then reviewed retrospectively. A five-question screening instrument was used to indicate suspected CVI. The majority of the 81 families who responded to the questionnaire reported some level of visual perceptual difficulty in their child. Among this cohort, the prevalence of suspected CVI as indicated by the screening questionnaire was 38%. Only ametropia was found to have a significant association with suspected CVI, although this increased the correct prediction of suspected CVI outcome by only a small amount. Results suggest that children with Down syndrome are more likely to experience problems consistent with cerebral visual impairment, and that these may originate from a similar brain dysfunction to that which contributes to high levels of ametropia and failure to emmetropise. It is important that behavioural features of CVI are recognised in children with Down syndrome, further investigations initiated and appropriate management applied. [ABSTRACT FROM AUTHOR]

Purpose. To summarize and review the common ophthalmic anomalies in children with trisomy 21 (Down syndrome) in order to propose an update to current clinical recommendations. Methods. A retrospective chart review, systemic literature review, and international survey of the frequency of ocular abnormalities, screening schedules, and challenging aspects examining children with trisomy 21. The chart review included patients treated at the Department of Ophthalmology at the University Hospital of Zurich over a two-year period. The international survey was submitted to the members of the Swiss Society of Ophthalmology, Slovenian Ophthalmological Society, and European Pediatric Ophthalmology Society. Results. Analysis of 52 patient records during the study period revealed refractive errors (astigmatism: 54% of patients, hyperopia: 26%, and myopia: 15%) as the most common diagnosis, whereas childhood cataract was reported in 5%. This is in concordance with the extended literature review of 249 publications, although congenital cataracts were reported to be higher than at our institution. The survey participants reported great challenges in taking care of these patients, despite their long professional experience (73% with over 10 years of experience). Conclusion. Care and treatment of children with trisomy 21 continues to be demanding for paediatric ophthalmologists. We recommend the following examination schedule for these patients: first, ophthalmological examination at 6–12 months of age, then once in 3–6 months for children under 2 years of age, once in 6 months for children 2–5 years of age, annually for children 5–10 years of age, and thereafter, to be decided on an individual basis depending on the presenting ocular abnormalities of the patient. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is frequently associated with cataract, but there remains scant information about DS cataract morphology. Supra-nuclear cataracts in DS have been proposed as indicative of beta-amyloid (Aβ) aggregation and thus potential biomarkers for Alzheimer's (AD). This study employed anterior segment OCT (AS-OCT) and slit-lamp (SL) photography to image the crystalline lens in DS, compared with adult controls. Lens images were obtained post-dilation. Using MATLAB, AS-OCT images were analysed and lens opacities calculated as pixel intensity and area ratios. SL images were classified using LOCS III. Subjects were n = 28 DS (mean ± SD 24.1 ± 14.3years), and n = 36 controls (54.0 ± 3.4years). For the DS group, AS-OCT imaging revealed the frequent presence of small dot opacities (27 eyes, 50%) in the cortex and nucleus of the lens, covering an area ranging from 0.2–14%. There was no relation with age or visual acuity and these dot opacities (p > 0.5) and they were not present in any control lenses. However, their location and morphology does not coincide with previous reports linking these opacities with Aβ accumulation and AD. Four participants (14%) in the DS group had clinically significant age-related cataracts, but there was no evidence of early onset of age-related cataracts in DS. [ABSTRACT FROM AUTHOR]

Asma AA Zahidi, J Margaret Woodhouse, Jonathan T Erichsen, Matt J Dunn Research Unit for Nystagmus, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK Abstract: Infantile nystagmus (IN), previously known as congenital nystagmus, is an involuntary to-and-fro movement of the eyes that persists throughout life. IN is one of three types of early-onset nystagmus that begin in infancy, alongside fusion maldevelopment nystagmus syndrome and spasmus nutans syndrome. Optometrists may also encounter patients with acquired nystagmus. The features of IN overlap largely with those of fusion maldevelopment nystagmus syndrome, spasmus nutans syndrome, and acquired nystagmus, yet the management for each subtype is different. Therefore, the optometrist’s role is to accurately discern IN from other forms of nystagmus and to manage accordingly. As IN is a lifelong condition, its presence not only affects the visual function of the individual but also their quality of life, both socially and psychologically. In this report, we focus on the approaches that involve optometrists in the investigation and management of patients with IN. Management includes the prescription of optical treatments, low-vision rehabilitation, and other interventions such as encouraging the use of the null zone and referral to support groups. Other treatments available via ophthalmologists are also briefly discussed in the article. Keywords: eye movements, visual acuity, reading performance, low vision, null zone, optometric investigation

Infantile nystagmus (IN) describes a regular, repetitive movement of the eyes. A characteristic feature of each cycle of the IN eye movement waveform is a period in which the eyes are moving at minimal velocity. This so-called "foveation" period has long been considered the basis for the best vision in individuals with IN. In recent years, the technology for measuring eye movements has improved considerably, but there remains the challenge of calibrating the direction of gaze in tracking systems when the eyes are continuously moving. Identifying portions of the nystagmus waveform suitable for calibration typically involves time-consuming manual selection of the foveation periods from the eye trace. Without an accurate calibration, the exact parameters of the waveform cannot be determined. In this study, we present an automated method for segmenting IN waveforms with the purpose of determining the foveation positions to be used for calibration of an eye tracker. On average, the "point of regard" was found to be within 0.21° of that determined by hand-marking by an expert observer. This method enables rapid clinical quantification of waveforms and the possibility of gaze-contingent research paradigms being performed with this patient group. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to educate professionals, families and supporters about the importance of ensuring regular eye examinations for the people with learning disabilities. Design/methodology/approach: This is a general review of the type and prevalence of visual problems of which people with learning disabilities are most at risk. Findings: Eye problems in people with learning disabilities are common but are often over-looked. Practical implications: Uncorrected refractive errors mean that people are unnecessarily denied experiences and learning opportunities. Spectacles are a simple solution, and most people can be supported to wear them. Cataracts and keratoconus are conditions that can lead to visual impairment, but which are now treatable and learning disabilities should not be a contra-indication to treatment. Untreatable eye conditions mean lifelong visual impairment, but if this is not recognised, care may be inappropriate or the learning disability assumed to be greater than it is. Originality/value: The review describes how families and supporters can organise successful eye examinations, to ensure that no-one with learning disabilities has an eye condition that is not managed appropriately. [ABSTRACT FROM AUTHOR]

Our objective was to present the findings of an opt-in, school-based eye care service for children attending 11 special schools in England and use these findings to determine whether a vision screening programme would be appropriate for this population. Data from eye examinations provided to 949 pupils (mean age 10.7 years) was analysed to determine the prevalence and aetiology of visual deficiencies and reported eye care history. For 46.2% (n = 438) of pupils, a visual deficiency was recorded. 12.5% of all the children seen (n = 119) had a visual deficiency that was previously undiagnosed. Referral for a medical opinion was made for 3.1% (n = 29) of pupils seen by the service. Spectacle correction was needed for 31.5% (n = 299) of pupils; for 12.9% (122) these were prescribed for the first time. 3.7% (n = 11) of parents/carers of pupils needing spectacles chose not to use the spectacle dispensing service offered in school. Eye care history was available for 847 pupils (89.3%). Of the pupils for whom an eye care history was available, 44% (n = 373) reported no history of any previous eye care and10.7% (n = 91) reported a history of attending a community optical practice/opticians. Only one pupil from the school entry 4–5 age group (0.6% of age group n = 156) would have passed vision screening using current Public Health England screening guidelines. Children with a diagnosis of autism were significantly less likely to be able to provide a reliable measurement of visual acuity. This study supports previously published evidence of a very high prevalence of visual problems in children with the most complex needs and a significant unmet need in this group. It demonstrates routine school entry vision screening using current Public Health England guidelines is not appropriate for this group of children and very low uptake of community primary eye care services. [ABSTRACT FROM AUTHOR]

Keratoconus is a potentially sight-threatening condition in which the cornea distorts and becomes fragile, and without treatment can lead to severe visual impairment. The condition is much more common in people with Down's syndrome and likely to be more common in people with other types of learning disability. Since the advent of a new treatment, corneal cross-linkage, which is only applicable in the early stages of the condition, early diagnosis has become imperative. However, people with learning disabilities are less likely to complain of poor vision and more likely to have poor vision and astigmatism which can mask early changes, so keratoconus can be missed. It is essential that those caring for and supporting people with a learning disability appreciate the risk of keratoconus and ensure that clients have regular and appropriate eye examinations from the age of ten years. When keratoconus is diagnosed it is important to discuss treatment options and for carers to understand the effects of the condition to minimise sight loss and maximise quality of life. [ABSTRACT FROM AUTHOR]

Purpose Previous studies have reported that eye movements differ between good/average and poor readers. However, these studies have been limited to investigating eye movements during reading related tasks, and thus, the differences found could arise from deficits in higher cognitive processes involved in reading rather than oculomotor performance. The purpose of the study is to determine the extent to which eye movements in children with delayed reading skills are different to those obtained from children with good/average reading skills in non-reading related tasks. Methods After a screening optometric assessment, eye movement recordings were obtained from 120 children without delayed reading skills and 43 children with delayed reading skills (4 to 11 years) using a Tobii TX300 eye tracker. Cartoon characters were presented horizontally from −20° to +20° in steps of 5° to study saccades. An animated stimulus in the centre of the screen was presented for 8 seconds to study fixation stability. Saccadic main sequences, and the number and amplitude of the saccades during fixation were obtained for each participant. Children with delayed reading skills ( n = 43) were unmasked after data collection was completed. Medians and quartiles were calculated for each eye movement parameter for children without ( n = 120) and with ( n = 43) delayed reading skills. Results Independent t-tests with Bonferroni correction showed no significant differences in any of the saccadic main sequence parameters (Slope, Intercept, A, n and Q ratio) between children without and with delayed reading ( p > 0.01). Similarly, no significant differences were found in the number of saccades and their amplitude during the fixation task between the two groups ( p > 0.05). Further, none of the gross optometric parameters assessed (visual acuity, refractive error, ocular alignment, convergence, stereopsis and accommodation accuracy) were found to be associated with delayed reading skills ( p > 0.05). Conclusions Eye movements in children with delayed reading skills are quantitatively similar to those found in children without delayed reading skills. These findings suggest that, in these children, delayed reading skills are not associated with eye movements and further question interventions targeted at improving eye movement control. [ABSTRACT FROM AUTHOR]

Purpose: This review will describe the current state of knowledge of the most common ocular/visual defects that eye care practitioners will encounter in children with Down's syndrome, ie refractive errors, poor accommodation, strabismus and acuity deficits, concentrating on the contribution that my research team has made to this field. It will also describe the evidence-based management guidelines that arise from the research, as well as the importance of dissemination in ensuring that research translates into changes in clinical practice. Summary of findings: Children with Down's syndrome show a different pattern of refractive development; in short, most do not emmetropise, and this suggests early refractive correction is needed. Since three-quarters of children have an accommodative deficit that remains when distance refractive errors are corrected, it is imperative that accommodation is measured regularly and corrected with bifocals if defective. Strabismus is common irrespective of refractive error or even in emmetropia, and astigmatism tends to increase throughout childhood, so vigilance is needed at all ages. Even with best correction, acuity and contrast sensitivity are relatively poor in Down's syndrome and practitioners have a responsibility to ensure that parents, teachers and other professionals are aware of visual defects. Finally, clinical researchers must think beyond high-impact journals, and must involve themselves in active dissemination to ensure that their work reaches the people who can make a difference. [ABSTRACT FROM AUTHOR]