Ocular Emergencies in Children

This chapter covers general bedside and chairside examination procedures and instruments used to examine a pediatric patient in an acute care setting. Pediatric patients may present to an emergency room or present emergently in any clinical setting with a wide variety of acute ocular conditions. When working in an emergency room or hospital-based setting, it is unlikely that a clinician will have all of the exam equipment typically used for routine care. The authors review the various ocular imaging techniques used to obtain a view of the internal structures of the eye, orbit, head, and brain when external examination is not sufficient. The procedures described aid the clinician in appropriately and thoroughly evaluating pediatric patients presenting with ocular emergencies.

Multimodal imaging supporting the pathophysiology of white dot syndromes

White dot syndromes (WDS) represent a heterogeneous group of inflammatory diseases, primarily affecting the outer retina, choriocapillaris and choroid. Recent advances in the field of ocular imaging and development of new technologies, including optical coherence tomography angiography (OCT-A), have allowed a better characterization of the morphology of these conditions. This review will analyse the WDS from an imaging-based perspective, providing a better understanding of the pathophysiology underlying these disorders.

Long-Term Clinical and Multimodal Imaging Findings in Patients with Disseminated Mycobacterium Chimaera Infection

Background: To analyze long-term ophthalmic clinical and multimodal imaging findings of disseminated Mycobacterium (M.) chimaera infection after cardiothoracic surgery among the Swiss Cohort. Methods: Systemic and multimodal ophthalmic imaging and clinical findings including rate of recurrence were reviewed and correlated to a previously proposed classification system of choroidal lesions and classification of ocular disease. Main Outcomes Measures: long-term clinical and multimodal ocular imaging findings of M. chimaera. Results: Twelve patients suffering from systemic infection from M. chimaera were included. Mean age at the first ophthalmic examination was 59 years (range from 48 to 66 years). Mean duration of the follow-up was 22.63 ± 17.8 months. All patients presented with bilateral chorioretinal lesions at baseline; 5 patients had additional signs, including optic disc swelling (2), choroidal neovascularization (1), retinal neovascularization (1) and cilioretinal vascular occlusion (1). Four recurrence events after discontinuation or adjustment of the antibiotic treatment were observed. Progressive choroiditis was seen in 5 patients under treatment, 4 of them deceased. Conclusions: Expertise from ophthalmologists is not only relevant but also critical for the assessment of the adverse drug effect of antimycobacterial treatment along with monitoring therapeutic response and identifying recurrences.

Exploring Multimodal Ocular Imaging for Retinal Biomarkers of Alzheimer’s Disease, Frontotemporal Dementia, and Cognitively Normal Subjects

Background and ObjectivesAlzheimer’s disease (AD) and frontotemporal dementia (FTD) are difficult to reliably differentiate clinically. While their distinct pathologies may be captured by existing diagnostic modalities, these are expensive, time-consuming, and often inaccessible. Dementias are associated with visual dysfunctions, perhaps due to changes in the retina, a developmental outgrowth of the central nervous system. We explore the role of multimodal ocular imaging in the diagnosis of two dementias, AD and FTD.MethodsWe recruited 5 AD participants, 2 FTD participants, and 9 age-matched controls. Each participant underwent comprehensive ophthalmologic examination and imaging (optical coherence tomography (OCT), OCT-angiography (OCTA), wide-field fundus photography, near-infrared imaging, and fundus autofluorescence). Ocular findings were correlated with cerebral amyloid burden, as measured by [11C]PiB PET.ResultsOCT analysis identified a trend toward differences in retinal nerve fiber layer (RNFL) thicknesses among dementia subtypes (p = 0.064). AD eyes had increased RNFL thicknesses compared to FTD (p = 0.046) and control eyes (p = 0.046), and AD RNFL thickness was positively associated with amyloid burden (p = 0.037). OCTA fractal analysis revealed decreased vascular complexity within the retinal superficial vascular complex in AD compared to FTD eyes (p = 0.035). Lastly, fundus autofluorescence demonstrated increased signal intensity in AD eyes compared to control eyes (p = 0.046). However, these findings were not statistically significant following correction for multiple comparisons.DiscussionDespite identifying trends toward differences in retinal layer thicknesses unique to individuals with AD and FTD, our study suggests that changes in retinal thicknesses alone may not serve as reliable biomarkers for distinguishing between dementia subtypes. However, multiple ocular imaging modalities may be considered in conjunction with clinical presentation to aid in diagnosing and monitoring AD and FTD.Trial registrationThe study was prospectively registered on clinicaltrials.gov (NCT03699644) on October 9, 2018.

Visual electrophysiology in the assessment of toxicity and deficiency states affecting the visual system

Visual disturbance or visual failure due to toxicity of an ingested substance or a severe nutritional deficiency can present significant challenges for diagnosis and management, for instance, where an adverse reaction to a prescribed medicine is suspected. Objective assessment of visual function is important, particularly where structural changes in the retina or optic nerve have not yet occurred, as there may be a window of opportunity to mitigate or reverse visual loss. This paper reviews a number of clinical presentations where visual electrophysiological assessment has an important role in early diagnosis or management alongside clinical assessment and ocular imaging modalities. We highlight the importance of vitamin A deficiency as an easily detected marker for severe combined micronutrient deficiency.

Multimodal Retinal Imaging in Spinocerebellar Ataxia Type 1 Maculopathy

Objectives: The objective of the study was to investigate and report the multimodal ocular imaging findings associated with spinocerebellar ataxia type 1 (SCA 1) associated maculopathy. Methods: A full ophthalmologic assessment was completed in a 70-year-old male with confirmed SCA1 and noted progressive bilateral vision loss. Investigations included dilated fundus examination, full-field electroretinography, and swept-source optical coherence tomography (OCT). Results: On neurologic and ophthalmologic examination, he was found to have hypermetric saccades, horizontal nystagmus, and reduced color vision bilaterally. His best-corrected visual acuity was confirmed to be 20/80 OD and 20/100 OS at the time of consultation. Initial fundus photography was most notable for bilateral hypopigmentation of the fovea. Corresponding OCT imaging demonstrated an attenuation of the ellipsoid zone, in keeping with photoreceptor loss. Conclusion: The ocular imaging results suggest that the vision loss in the presented case occurred in the context of pigmentary macular dystrophy secondary to photoreceptor dysfunction and retinal pigment epithelial degeneration. This association offers an explanation with respect to the progressive vision loss, but further analyses would be required to determine the temporal correlation of clinical symptoms with imaging abnormalities. These findings suggest that SCA1 be considered as a potential cause for vision impairment, with possible benefits of visual assessment at the time of diagnosis.

Towards distortion-free imaging of the eye

The high power of the eye and optical components used to image it result in “static” distortion, remaining constant across acquired retinal images. In addition, raster-based systems sample points or lines of the image over time, suffering from “dynamic” distortion due to the constant motion of the eye. We recently described an algorithm which corrects for the latter problem but is entirely blind to the former. Here, we describe a new procedure termed “DIOS” (Dewarp Image by Oblique Shift) to remove static distortion of arbitrary type. Much like the dynamic correction method, it relies on locating the same tissue in multiple frames acquired as the eye moves through different gaze positions. Here, the resultant maps of pixel displacement are used to form a sparse system of simultaneous linear equations whose solution gives the common warp seen by all frames. We show that the method successfully handles torsional movement of the eye. We also show that the output of the previously described dynamic correction procedure may be used as input for this new procedure, recovering an image of the tissue that is, in principle, a faithful replica free of any type of distortion. The method could be extended beyond ocular imaging, to any kind of imaging system in which the image can move or be made to move across the detector.