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Background/aims To investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study. Methods Handheld SD-OCT (Envisu C2300) was used to acquire horizontal scans through the centre of the fovea in biological parents of patients with OCA (n=28; mean age±SD=40.43±8.07 years) and age-matched and ethnicity-matched controls (n=28; mean age±SD=38.04±10.27 years). Sequence analysis was performed for variants in known genes associated with OCA. Best-corrected visual acuity (BCVA), presence of foveal hypoplasia and grade, foveal, parafoveal and perifoveal thickness measurements of total retinal layers (TRL), inner retinal layers (IRL) and outer retinal layers (ORL) thickness were measured. Results Foveal hypoplasia was identified in 32.14% of OCA carriers; grade 1 in all cases. OCA carriers demonstrated significant thicker TRL thickness (median difference: 13.46 µm, p=0.009) and IRL thickness (mean difference: 8.98 µm, p<0.001) at the central fovea compared with controls. BCVA of carriers was between -0.16 and 0.18 logMAR (mean: 0.0 logMAR). No significant differences in BCVA was noted between OCA carriers or controls (p=0.83). In the OCA carriers, we identified previously reported pathogenic variants in TYR, OCA2 and SLC45A2, novel OCA2 variants (n=3) and heterozygosity of the pathogenic TYR haplotype. Conclusion We have, for the first time, identified foveal abnormalities in OCA carriers. This provides clinical value, particularly in cases where limited phenotype data are available. Our findings raise the possibility that previously reported mild cases of foveal hypoplasia or isolated foveal hypoplasia could correspond to OCA carrier status. [ABSTRACT FROM AUTHOR]

Background The genetic basis of monocular elevation deficiency (MED) is unclear. It has previously been considered to arise due to a supranuclear abnormality. Methods Two brothers with MED were referred to Leicester Royal Infirmary, UK from the local opticians. Their father had bilateral ptosis and was unable to elevate both eyes, consistent with the diagnosis of congenital fibrosis of extraocular muscles (CFEOM). Candidate sequencing was performed in all family members. Results Both affected siblings (aged 7 and 12 years) were unable to elevate the right eye. Their father had bilateral ptosis, left esotropia and bilateral limitation of elevation. Chin up head posture was present in the older sibling and the father. Bell's phenomenon and vertical rotational vestibulo-ocular reflex were absent in the right eye for both children. Mild bilateral facial nerve palsy was present in the older sibling and the father. Both siblings had slight difficulty with tandem gait. MRI revealed hypoplastic oculomotor nerve. Left anterior insular focal cortical dysplasia was seen in the older sibling. Sequencing of TUBB3 revealed a novel heterozygous variant (c.1263G>C, p.E421D) segregating with the phenotype. This residue is in the C-terminal H12 α-helix of β-tubulin and is one of three putative kinesin binding sites. Conclusion We show that familial MED can arise from a TUBB3 variant and could be considered a limited form of CFEOM. Neurological features such as mild facial palsy and cortical malformations can be present in patients with MED. Thus, in individuals with congenital MED, consideration may be made for TUBB3 mutation screening. [ABSTRACT FROM AUTHOR]

The article focuses on a study for investigating the potential of hand-held optical coherence tomography (HH-OCT) to improve diagnosis in anterior segments (AS) by visualizing the anterior and posterior eye structures without general anaesthetic (GA) or sedation. It mentions AS optical coherence tomography (OCT) findings allow diagnosis of iridocorneal endothelial syndrome (ICE) because of endothelium irregularity. It also mentions a case of a 2 month old baby with left corneal opacity.

Purpose: To characterize in vivo anatomic abnormalities of the iris in albinism compared with healthy controls using anterior segment optical coherence tomography (AS-OCT) and to explore the diagnostic potential of this technique for albinism. We also investigated the relationship between iris abnormalities and other phenotypical features of albinism. Design: Prospective cross-sectional study. Participants: A total of 55 individuals with albinism and 45 healthy controls. Methods: We acquired 4.37×4.37-mm volumetric scans (743 A-scans, 50 B-scans) of the nasal and temporal iris in both eyes using AS-OCT (3-μm axial resolution). Iris layers were segmented and thicknesses were measured using ImageJ software. Iris transillumination grading was graded using Summers and colleagues' classification. Retinal OCT, eye movement recordings, best-corrected visual acuity (BCVA), visual evoked potential (VEP), and grading of skin and hair pigmentation were used to quantify other phenotypical features associated with albinism. Main Outcome Measures: Iris AS-OCT measurements included (1) total iris thickness, (2) stroma/anterior border (SAB) layer thickness, and (3) posterior epithelial layer (PEL) thickness. Correlation with other phenotypical measurements, including (1) iris transillumination grading, (2) retinal layer measurements at the fovea, (3) nystagmus intensity, (4) BCVA, (5) VEP asymmetry, (6) skin pigmentation, and (7) hair pigmentation (of head hair, lashes, and brows). Results: The mean iris thickness was 10.7% thicker in controls (379.3±44.0 μm) compared with the albinism group (342.5±52.6 μm; P >0.001), SAB layers were 5.8% thicker in controls (315.1±43.8 μm) compared with the albinism group (297.7±50.0 μm; P=0.044), and PEL was 44.0% thicker in controls (64.1±11.7 μm) compared with the albinism group (44.5±13.9 μm; P <0.0001). The most ciliary quartile of the PEL yielded a sensitivity of 85% and specificity of 78% for detecting albinism. Phenotypic features of albinism, such as skin and hair pigmentation, BCVA, and nystagmus intensity, were significantly correlated to AS-OCT iris thickness measurements. Conclusions: We have characterized in vivo abnormalities of the iris associated with albinism for the first time and show that PEL thickness is particularly affected. We demonstrate that PEL thickness has diagnostic potential for detecting iris abnormalities in albinism. Anterior segment OCT iris measurements are significantly correlated to BCVA and nystagmus intensity in contrast to iris transillumination grading measurements that were not. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [ABSTRACT FROM AUTHOR]

Purpose: Our primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses., Methods: Dilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings., Results: For the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash., Conclusions: Age-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.

Albinism refers to a group of genetic abnormalities in melanogenesis that are associated neuronal misrouting through the optic chiasm. We perform quantitative assessment of visual pathway structure and function in 23 persons with albinism (PWA) and 20 matched controls using optical coherence tomography (OCT), volumetric magnetic resonance imaging (MRI), diffusion tensor imaging and visual evoked potentials (VEP). PWA had a higher streamline decussation index (percentage of total tractography streamlines decussating at the chiasm) compared with controls (Z = -2.24, p = .025), and streamline decussation index correlated weakly with inter-hemispheric asymmetry measured using VEP (r = .484, p = .042). For PWA, a significant correlation was found between foveal development index and total number of streamlines (r = .662, p < .001). Significant positive correlations were found between peri-papillary retinal nerve fibre layer thickness and optic nerve (r = .642, p < .001) and tract (r = .663, p < .001) width. Occipital pole cortical thickness was 6.88% higher (Z = -4.10, p < .001) in PWA and was related to anterior visual pathway structures including foveal retinal pigment epithelium complex thickness (r = -.579, p = .005), optic disc (r = .478, p = .021) and rim areas (r = .597, p = .003). We were unable to demonstrate a significant relationship between OCT-derived foveal or optic nerve measures and MRI-derived chiasm size or streamline decussation index. Our novel tractographic demonstration of altered chiasmatic decussation in PWA corresponds to VEP measured cortical asymmetry and is consistent with chiasmatic misrouting in albinism. We also demonstrate a significant relationship between retinal pigment epithelium and visual cortex thickness indicating that retinal pigmentation defects in albinism lead to downstream structural reorganisation of the visual cortex., (© 2018 Wiley Periodicals, Inc.)