Prevalence of Macular Microcystoid Lacunae in Autosomal Dominant Optic Atrophy Assessed With Adaptive Optics.

BACKGROUND: To assess the prevalence of macular microcystoid lacunae in patients with autosomal dominant optic atrophy (ADOA) and its association with visual function and inner retinal morphology. METHODS: The study included 140 participants with ADOA, with a mean age of 44 (SD ±19, range 7-82) years. Study participants with a genetically verified sequence variant in the OPA1 gene were examined with best-corrected visual acuity, contrast sensitivity, optical coherence tomography (Spectralis, Heidelberg) and adaptive optics fundus photography (rtx1, Imagine Eyes). Optically empty microcystoid spaces in the ganglion cell layer and inner plexiform layer were mapped by inspection of the 2 sets of images. Data were analyzed with a mixed model adjusted for age and sex with family and individual as random effect. RESULTS: Microcystoid lacunae were present in 32 of 140 participants (23%) including 18 males and 14 females. Microcystoid lacunae were associated with younger age ( P = 0.0503) and a smaller nerve fiber layer volume ( P = 0.035). No association was found between presence of microcystoid lacunae and visual acuity ( P = 0.2), contrast sensitivity ( P = 0.8), axial length ( P = 0.7), or ganglion cell layer volume ( P = 0.2). The analysis showed moderately reduced visual acuity in patients with microcystoid lacunae. Normal and severely impaired visual function were seen only in participants without microcystoid lacunae. CONCLUSION: In ADOA, macular microcystoid lacunae were found in 23% of the study participants and tended to be present in younger participants with moderate visual acuity reduction and a smaller nerve fiber layer volume. Further studies are needed to investigate whether cavities left by dead ganglion cells are predictors of decrease in visual function.

Iron overload and iron chelating agent exposure in anemia-associated outer retinal degeneration: a case report and review of the literature.

BACKGROUND: Deferoxamine retinopathy is the informally designated term used to describe a characteristic pattern of outer retinal degeneration in iron-overloaded chronic anemia patients who are treated with deferoxamine. We hypothesize that insufficiently treated iron overloading and not only deferoxamine is the cause of the retinal degeneration. Our case report is based on exposure histories of two anemia patients and literature review. CASE PRESENTATION: Both anemia patients presented with bilateral visual loss secondary to photoreceptor and retinal pigment epithelium degeneration. Chart review showed that visual loss came after a year-long slow, and rather monotonous rise in plasma ferritin concentrations, with no obvious relation to iron chelator exposure. In one patient, the onset of symptomatic visual loss came after a bout of fever followed by two additional febrile episodes, all accompanied by plasma ferritin spikes. Adjustment of iron chelation therapy did not improve visual function. Experimental studies clearly show that both systemic and intraocular exposure to iron ions can induce retinal degeneration. CONCLUSION: The available evidence indicates that retinal degeneration in chronic anemia patients treated by deferoxamine is cause by insufficient iron chelation, not by deferoxamine. The actual role of iron chelating agents may be to promote a long enough survival to allow the slow development of retinal siderosis.

Cone photoreceptor density in the Copenhagen Child Cohort at age 16-17 years.

PURPOSE: To examine cone density in relation to gestational and morphological parameters in the Copenhagen Child Cohort (CCC2000). METHODS: The macula was imaged using adaptive optics in 1,296 adolescents aged 16-17 years. Axial length and distance visual acuity were determined. Absolute and angular cone photoreceptor density were analysed for an 80 × 80-pixel area, 2 degrees temporal to the fovea. Association with axial length was analysed with linear regression. Correlation with visual acuity was described with a Pearson correlation coefficient. Associations of cone density with gestational parameters, maternal smoking, sex and age were analysed using multiple regression adjusted for axial length. RESULTS: Mean absolute cone density was 30,007 cones/mm2 (SD ± 3,802) and mean angular cone density was 2,383 cones/deg2 (SD ± 231). Peri- and postnatal parameters, sex and age had no statistically significant effect on cone density (p > 0.05). Absolute cone density decreased with longer axial length (-2,855 cones/mm2 per mm or -9.7% per mm, p < 0.0001). For angular density, which included a correction for the geometrical enlargement of the eye with axial length, a decrease with axial length was detectable, but it was small (-20 cones/deg2 per mm or -0.84% per mm, p = 0.009). CONCLUSIONS: The decrease in cone density per unit solid angle with increasing axial length was small, less than 1 percent per mm, indicating that expansion of the posterior pole during the development of refraction takes place without a clinically significant loss of cones. Perinatal parameters, within the spectrum presented by the study population, had no detectable effect on cone density.

Visual Function and Inner Retinal Structure in Relation to Birth Factors in Autosomal Dominant Optic Atrophy.

Purpose: The extreme variation in expressivity of autosomal dominant optic atrophy (ADOA) is unexplained. It is present from early childhood, why there is reason to search for pre- and perinatal risk factors for poor vision in ADOA. The process of ganglion cell pruning in the fetus is of interest because mitochondria are involved in apoptosis. We hypothesized that suboptimal mitochondrial function makes the developing retina and optic nerve vulnerable to fetal stress in ADOA. We have examined visual function and inner retinal layer structure in relation to birth parameters in ADOA. Methods: The study included 142 participants with OPA1 ADOA, 62 unaffected first-degree relatives, and 90 unrelated control subjects. Outcome measures included best-corrected visual acuity, microperimetric sensitivity, nerve fiber layer (NFL) volume, and ganglion cell layer (GCL) volume. Descriptive parameters included birth weight, maternal age at birth, birth complications, and gestational age. Analysis was made using mixed modeling. Results: The analysis showed a significant positive association between microperimetric sensitivity and longer gestational age in ADOA (0.5 dB/week, P = 0.017). Interaction analysis showed a significant different association between microperimetric sensitivity and gestational age between participants with ADOA and the control groups (P = 0.007) and a significant difference in association between NFL volume and birth weight (P = 0.04) and gestational age (P = 0.02) between variant types. Conclusions: The study suggests that gestational age and birth weight may affect the expressivity of ADOA. The results support that prospectively collected pre- and perinatal data should be included in future studies of the natural history of ADOA.

The effect of serifs and stroke contrast on low vision reading.

PURPOSE: Patients with low vision are generally recommended to use the same fonts as individuals with normal vision. However, we are yet to fully understand whether stroke width and serifs (small ornamentations at stroke endings) can increase readability. This study's purpose was to characterize the interaction between two factors (end-of-stroke and stroke width) in a well-defined and homogenous group of patients with low vision. METHODS: Font legibility was assessed by measuring word identification performance of 19 patients with low vision (autosomal dominant optic atrophy [ADOA] with a best-corrected average visual acuity 20/110) and a two-interval, forced-choice task was implemented. Word stimuli were presented with four different fonts designed to isolate the stylistic features of serif and stroke width. RESULTS: Font-size threshold and sensitivity data revealed that using a single measure (i.e., font-size threshold) is insufficient for detecting significant effects but triangulation is possible when combined with signal detection theory. Specifically, low stroke contrast (smaller variation in stroke width) yielded significantly lower thresholds and higher sensitivity when a font contained serifs (331 points; d' = 1.47) relative to no serifs (345 points; d' = 1.15), E(µsans, low - µserif, low) = -14 points, 95 % Cr. I. = [-24, -5], P(δ > 0) = 0.99 and E(µserif, low - µsans, low) = 0.32, 95 % Cr. I. = [0.16, 0.49], P(δ > 0) = 0.99. CONCLUSION: In people with low visual acuity caused by ADOA, the combination of serifs and a uniform stroke width resulted in better text legibility than other combinations of uniform/variable stroke widths and presence/absence of serifs.

Ocular and systemic associations and heritability of retinal arterial wall-to-lumen ratios in a twin cohort.

PURPOSE: To investigate ocular and systemic factors associated with the retinal arterial wall-to-lumen ratio (WLR) and to determine the relative contribution of genetic and environmental variation to WLR in healthy adults. METHODS: This cross-sectional twin study included 78 monozygotic and 67 dizygotic same-sex twin pairs aged 58.4 ± 9.8 (mean ± SD) years. Lumen diameter (LD) and outer diameter (OD) of a superotemporal retinal artery were measured using adaptive optics fundus photography, and the WLR was calculated. Linear mixed model regression analysis of associations with WLR comprised the descriptive variables ocular axial length (AL), intraocular pressure (IOP), height, weight, body mass index (BMI), smoking, blood pressure, high density (HDL), low density (LDL) and very low density (VLDL) lipoproteins, total cholesterol and triglycerides. The relative influence of genes and environment on WLR was calculated through polygenetic modelling. RESULTS: Increasing age and arterial blood pressure were associated with a higher WLR, while increasing retinal artery OD and ocular AL were associated with a lower WLR. Sex, smoking status, BMI, IOP, cholesterol levels or triglycerides had no detectable impact on the WLR. Broad-sense heritability of WLR was 21% (95% CI: 1-41%), while environmental factors accounted for the remaining 79% of the interindividual variance (95% CI: 59-99%). CONCLUSION: Retinal artery wall thickness was closely linked to increasing age and higher arterial blood pressure, the latter being mediated by the environment over genes.

Vision-related quality of life and visual ability in patients with autosomal dominant optic atrophy.

PURPOSE: The purpose of the study was to evaluate vision-related quality of life and visual ability in patients with OPA1 autosomal dominant optic atrophy (ADOA). METHODS: This cross-sectional, observational study included 145 participants with a mutation in the OPA1 gene associated with ADOA, 63 mutation-free first-degree relatives and 92 healthy subjects unrelated to the families. Participants underwent a clinical eye examination, and adult participants completed the National Eye Institute Visual Function Questionnaire (NEI-VFQ-39), while children completed the Cardiff Visual Ability Questionnaire for Children (CVAQC). RESULTS: In adults with ADOA, both mean visual acuity (VA) and mean contrast sensitivity (CS) were significantly inferior to both first-degree relatives and unrelated controls (p < 0.001). In children with ADOA, mean VA was significantly lower compared with first-degree relatives (p = 0.0052), whereas CS was not (0.127). Adults with ADOA scored lower than both comparator groups on composite score (p < 0.001), general health subscale (p = 0.0075) and all vision-related subscales (p < 0.001) except the ocular pain subscale (p = 0.2). In children with ADOA, the median CVAQC logit score was significantly lower compared with first-degree relatives (p = 0.037). The science lessons subscale was significantly lower for children with ADOA compared with first-degree relatives (p = 0.046), as well as the language lessons subscale (p = 0.038). For adults, composite score and subscale scores were significantly associated with both VA, CS and fixation status. CONCLUSION: OPA1 mutation is associated with lower quality of life and visual ability in patients with ADOA compared with both first-degree relatives and unrelated controls. VA, CS and fixation status affect quality of life in patients with ADOA.

A UNILATERAL FOVEAL VITELLIFORM LESION IN A CHOROIDEREMIA CARRIER.

PURPOSE: To describe a unilateral foveal vitelliform lesion associated with subnormal visual acuity in a choroideremia carrier. METHODS: A retrospective case report, assessment of the best-corrected visual acuity, fundus photography, wide-angle scanning laser ophthalmoscopy, optical coherence tomography, and microperimetry. RESULTS: A 37-year-old woman with a pathogenic 907C>T mutation in the choroideremia gene encoding Rab escort protein-1 presented with blurred vision in her left eye.The Snellen best-corrected visual acuity was 20/20 in the right eye and 20/32 in the left eye, a unilateral decrease because it was 20/20 in both eyes at the most recent examination nine years earlier. In the left eye, a large vitelliform lesion with a diameter of 1,300 µ m had developed in the fovea, whereas in the right eye, a smaller similar lesion was seen close to the fovea. Both eyes showed classical radial patterns of multiple bright fundus patches with associated autofluorescence defects and focal drusenoid lesions of the outer retina. CONCLUSION: With its large size and foveal location the vitelliform lesion in this patient's left eye is an unusual manifestation in an otherwise common Rab escort protein-1 mutation carrier state, and its unilaterality fits the assumption of random X-chromosome inactivation.

Multi-modal and multi-scale clinical retinal imaging system with pupil and retinal tracking.

We present a compact multi-modal and multi-scale retinal imaging instrument with an angiographic functional extension for clinical use. The system integrates scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT) and OCT angiography (OCTA) imaging modalities and provides multi-scale fields of view. For high resolution, and high lateral resolution in particular, cellular imaging correction of aberrations by adaptive optics (AO) is employed. The entire instrument has a compact design and the scanning head is mounted on motorized translation stages that enable 3D self-alignment with respect to the subject's eye by tracking the pupil position. Retinal tracking, based on the information provided by SLO, is incorporated in the instrument to compensate for retinal motion during OCT imaging. The imaging capabilities of the multi-modal and multi-scale instrument were tested by imaging healthy volunteers and patients.

Peripheral bright streaks in tuberous sclerosis.

PURPOSE: To describe the finding of bright hyperautofluorescent streaks in the peripheral retina in tuberous sclerosis. OBSERVATIONS: A woman with a pathogenic TSC1 mutation and cutaneous manifestations of tuberous sclerosis underwent fundus examination and was found to have a cluster of thin, yellowish streaks in the inferior peripheral fundus of her left eye. The streaks were hyperautofluorescent in blue light and associated with irregular thickening of the photoreceptor-pigment epithelium complex on optical coherence tomography. CONCLUSIONS AND IMPORTANCE: The cluster of outer retinal abnormalities in a sector of the peripheral retina in one eye of a TSC1 patient has features in common with the more centrally located and less numerous lesions called achromatic patches. The resemblance of the streak pattern with the pattern of hypoautofluorescence in X-linked retinopathies suggests that the streaks may represent a clone of cells derived from a single somatic mutation in TSC1. The identification of this lesion type expands the scope of conditions that can be diagnosed by fundus imaging.

Global prevalence of asteroid hyalosis and projection of its future burden: a systematic review and meta-analysis.

Asteroid hyalosis is defined by the presence of white, snowball-like non-crystalline vitreous opacities that move with the vitreous and appear to be anchored to its matrix. Asteroid hyalosis commonly occurs in the absence of other identifiable ocular abnormalities and is usually an incidental finding. The vitreous opacities are usually invisible to the patient and asymptomatic, but asteroid hyalosis can be a significant obstacle to the examination of the fundus. The prevalence increases dramatically with age. The aetiology is unknown. We systematically reviewed the literature for epidemiological data, qualitatively reviewed available studies, conducted meta-analyses with demographical stratifications, evaluated temporal changes and estimated the future prevalence using forecasting analysis. Nine eligible studies were identified with data on 104 569 individuals. The overall population prevalence of asteroid hyalosis was 0.75% (95% confidence interval: 0.39-1.21%); however, the prevalence was highly age-dependent, ranging from 0.27% (95% confidence interval 0.12-0.49%) in individuals aged 0-39 years and gradually increasing to 3.07% (95% confidence interval 1.90-4.50%) in individuals aged ≥80 years. Male gender was an additional risk factor (odds ratio 1.80, 95% confidence interval 1.32-2.45, p = 0.00017). The estimated global prevalence was 10.7 million subjects in year 1950, which is expected to increase to 41.5 million in year 2020 and 91.2 million in year 2100. The prevalence of asteroid hyalosis is relevant because it impacts the utility of diagnostic strategies, especially screening methods for conditions such as diabetic retinopathy.