UNASSIGNED: To investigate the characteristics of microperimetry and optical coherence tomography (OCT) in congenital stationary night blindness (CSNB), as well as their structure-function association.
UNASSIGNED: This cross-sectional study included 32 eyes from 32 participants with CSNB, comprising 18 with complete CSNB and 14 with incomplete CSNB, along with 36 eyes from 36 CSNB-unaffected controls matched for age, sex, and spherical equivalent. Using MP-3 microperimetry, central retinal sensitivity was assessed within a 20° field, distributed across six concentric rings (0°, 2°, 4°, 6°, 8°, and 10°). OCT was used to analyze retinal and choroidal thickness. The study aimed to assess the overall and ring-wise retinal sensitivity, as well as choroidal and retinal thickness in CSNB and CSNB-unaffected controls, with a secondary focus on the relationship between retinal sensitivity and microstructural features on OCT.
UNASSIGNED: In comparison with CSNB-unaffected subjects, the overall and ring-wise retinal sensitivity as well as choroidal thickness were reduced in patients with CSNB (P < 0.001). Moreover, the central sensitivity in incomplete CSNB group was lower than in complete CSNB group (25.72 ± 3.93 dB vs. 21.92 ± 4.10 dB; P < 0.001). The retinal thickness in the CSNB group was thinner outside the fovea compared with the CSNB-unaffected group. Multiple mixed regression analyses revealed that point-to-point retinal sensitivity was significantly correlated with BCVA (P = 0.002) and the corresponding retinal thickness (P = 0.004).
UNASSIGNED: Examination of retinal sensitivity and OCT revealed different spatial distribution profiles in CSNB and its subtypes. In CSNB eyes, retinal sensitivity on microperimetry was associated with retinal thickness on OCT.

The purpose of this paper is to present a case study illustrating the importance of electrophysiological investigation in the diagnosis and serial monitoring of isolated congenital nystagmus.
Serial electophysiological monitoring was undertaken in the male proband over a 9-year period commencing with initial assessment at 12 weeks of age: Skin electroretinograms (sERGs) were initially absent but subsequently revealed low-amplitude responses, electronegative morphologies and notched flicker responses suggestive of incomplete congenital stationary night blindness (CSNB2), but with an absent dark-adapted rod-specific response, while flash visual evoked potentials (fVEPs) demonstrated persistent crossed asymmetry, typical of albinoid misrouting of the optic nerves. Molecular investigation confirmed a novel hemizygous frame shift mutation in the CACNA1F gene, considered to be pathogenic and causative of X-linked CSNB2; additionally, a novel heterozygous missense variation in one copy of the RIMS1 gene was identified, pathogenic mutations of which underpin late-onset autosomal dominant cone-rod dystrophy (type 7). Segregation studies confirmed maternal inheritance of both mutations in the clinically asymptomatic mother in whom depressed rod-specific responses were confirmed on sERG. The child\'s visual acuity has remained stable as have the sERGs which have been verified by recordings using scleral electrodes.
The importance of recording ERGs as part of evaluating infants who present with nystagmus, even with a normal fundus appearance, is supported. Further, sERGs were able to distinguish an apparent variant of CSNB2 and could give consistent results over many years. FVEP results add to the evidence that albinoid misrouting of the optic nerves may occur in cases of CSNB2. ERGs and fVEPs can provide valuable information in discriminating the relative diagnostic importance of multiple genetic abnormalities.

UNASSIGNED: Globally, pre-school children are the most at-risk population groups for vitamin A deficiency (VAD). The 2009 World Health Organization (WHO) report stated that one-third (190 million) of pre-school children worldwide are deficient in vitamin A. Both clinical and subclinical VAD have been a long-standing problem in developing countries. In Ethiopia, VAD was recognized as a public health problem 4-5 decades before. Since then, researches conducted in other parts of the country still showed varied and high prevalence, which is 2-8 times higher than WHO cut-off points. This community-based study was therefore conducted on pre-school children of rural kebeles in Farta district to determine the prevalence of clinical VAD (Bitot\'s spot and night blindness) and associated factors.
UNASSIGNED: A community-based cross-sectional mixed quantitative and qualitative study was conducted. Randomly selected 588 pre-school children participated in the study. The clinical aspect of the study investigated the presence of Bitot\'s spots on the children\'s eye with the aid of a magnifying loop and torch. Data on the history of night blindness were obtained from mothers/caregivers by using WHO standard questions. The qualitative study data were obtained via a key informant interview with the mothers/caregivers whose child has clinical VAD. Quantitative data were entered using Epi Data statistical software and analysed by using SPSS version 20 statistical software package. A bivariable logistic regression was employed, and variables that showed significant association with clinical VAD (P < 0.2) were entered a multivariable logistic regression model to identify independent predictors of clinical VAD.
UNASSIGNED: The prevalence of Bitot\'s spot and night blindness was 0.8% and 1.2%, respectively. Pre-school children who were from highland (AOR: 3.71; 95% CI: 1.01-13.68), a mother having antenatal care (ANC) visit during pregnancy of a child (AOR: 8.63; 95% CI: 2.58-28.79), family monthly income (AOR: 8.63; 95% CI: 2.58-28.79) and handwashing frequency were found to be determinants of VAD (p < 0.05).
UNASSIGNED: Clinical vitamin A deficiency in the study area is of public health concern because the prevalence of Bitot\'s and night blindness was above the WHO threshold level. Accordingly, effective preventive measures should be designed to reduce VAD prevalence.

BACKGROUND: Vitamin A deficiency is known for its adverse health consequences, such as blindness, growth retardation and death. To curb the problem, Ethiopia has implemented various public health measures although little has been done to examine the deficiency among pregnant and lactating women. As a result, this study assessed the prevalence of Vitamin A deficiency and associated factors among pregnant and lactating women in Lay Armachiho district, northwest Ethiopia.
METHODS: A community-based cross-sectional study was conducted on pregnant and lactating women in Lay Arimachiho district, northwest Ethiopia, using the multistage systematic sampling technique to select participants. The binary logistic regression model was fitted to test the effect of exposure variables, and the Adjusted Odds Ratio (AOR) with a 95% Confidence Interval (CI) and p-value < 0.05 were computed to identify the significance and the strength of the associations of variables with Vitamin A deficiency.
RESULTS: The study revealed that 13.7% of the pregnant and lactating women had night blindness and 0.4% had also Bitot\'s Spot. Over 35 years of age of mothers (AOR = 2.74; 95%CI: 1.15,7.43), less than USD 22.7 household monthly income (AOR = 8.9; 95%CI: 4.54,21.73), and poor hand washing practices after toilets (AOR = 8.87; 95% CI: 4.43,18.68) were positively associated with VAD, while mothers\' access to the media (AOR = 0.20; 95%CI:0.07, 0.59), formal education (AOR = 0.09; 95% CI: 0.03, 0.41), over 18 years of age at first marriage (AOR = 0.19; 95%CI: 0.08,0.36), and no fasting (AOR = 0.14; 95%CI: 0.04,0.46) were negatively associated.
CONCLUSIONS: Maternal Vitamin A deficiency was the major public health problem in Lay Armachiho district. Over 35 years of age of mothers, less than USD 22.7 household monthly income and poor hand washing practices after toilets were high risks for VAD, while mothers\' access to the media, formal education, over 18 years at first marriage, and no fasting were low risks. Therefore, community awareness about the risk of early marriage, poor hand hygiene practices after toilets, and fasting during pregnancy and lactating period were essential. Organizations working on maternal health need to focus on mothers with low incomes in order to reduce their deficiency in Vitamin A.

Congenital stationary night blindness (CSNB), in the complete form, is caused by dysfunctions in ON-bipolar cells (ON-BCs) which are secondary neurons of the retina. We describe the first disease causative variant associated with CSNB in the dog. A genome-wide association study using 12 cases and 11 controls from a research colony determined a 4.6 Mb locus on canine chromosome 32. Subsequent whole-genome sequencing identified a 1 bp deletion in LRIT3 segregating with CSNB. The canine mutant LRIT3 gives rise to a truncated protein with unaltered subcellular expression in vitro. Genetic variants in LRIT3 have been associated with CSNB in patients although there is limited evidence regarding its apparently critical function in the mGluR6 pathway in ON-BCs. We determine that in the canine CSNB retina, the mutant LRIT3 is correctly localized to the region correlating with the ON-BC dendritic tips, albeit with reduced immunolabelling. The LRIT3-CSNB canine model has direct translational potential enabling studies to help understand the CSNB pathogenesis as well as to develop new therapies targeting the secondary neurons of the retina.

To present phenotypic features of 22 patients with S-antigen (SAG) mutations.
Retrospective cohort study.
Twenty-one Japanese patients from 16 families with a homozygous c.924delA mutation and 1 patient with a homozygous c.636delT mutation in the SAG gene.
Clinical records on symptoms; best-corrected visual acuity; and Goldmann perimetry, fundus photography, fundus autofluorescence (FAF), OCT, and electroretinography results were reviewed.
Best-corrected visual acuity, Goldmann perimetry results, imaging findings, and electroretinography results.
Ten patients had Oguchi disease and 12 had retinitis pigmentosa (RP) with mean follow-up periods of 13.8 and 10.2 years, respectively. Retinitis pigmentosa patients were older (mean age, 56.0 years) than those with Oguchi disease (mean age, 22.1 years; P < 0.001) at the initial visit. Night blindness noted in childhood was the most common initial symptom for both Oguchi disease (80.0%) and RP (91.7%) patients. Best-corrected visual acuity in the logarithm of the minimum angle of resolution (logMAR) was well preserved in Oguchi disease patients (mean, 0.02 logMAR in both eyes) but reduced in most RP patients (mean, 1.32 logMAR [right eye] and 1.35 logMAR [left eye]). Similarly, the visual field in the retinal area was preserved in Oguchi disease patients (mean, 677 mm2 right eye and 667 mm2 left eye) and reduced in RP patients (mean, 369 mm2 right eye and 294 mm2 left eye). Fundus images revealed a characteristic golden sheen with no retinal degeneration in Oguchi disease patients, excluding 2 with macular degeneration detected by FAF, OCT, or both and 1 with mild retinal degeneration confirmed by OCT and fluorescein angiography. Pigmentary retinal degeneration most evident posteriorly was observed in RP patients, accompanied by a characteristic golden sheen in 12 of 14 patients undergoing ultra-widefield fundus imaging. OCT showed disrupted macular structure, and FAF revealed variable hypofluorescence. Electroretinography identified absent rod responses in both diseases, along with relative preservation of cone responses in Oguchi disease patients. Three patients showed progressive loss of the golden sheen based on fundus images, including 1 who demonstrated RP 26 years after the initial diagnosis of Oguchi disease.
Retinitis pigmentosa with SAG mutations often shows a characteristic golden sheen surrounding posterior pigmentary retinal degeneration. Oguchi disease can show progressive degeneration in adulthood, rarely resulting in RP.

The physiological modeling of retinal layers to provide an insight into how the incoming image is converted into its equivalent spike train that can be decoded by the human brain is a key issue. Most of the retinal layer models concentrate mainly on image compression, edge detection and image reconstruction. A retinal layer model to generate spike waveform corresponding to the visual information is not covered much in the literature. The aim of this study was to develop a mathematical model of retinal layers that has complex neural structures, that can detect the incoming signal and transform the signal into the equivalent spike train. The proposed retinal layer model includes a photoreceptor, an outer plexiform (OPL), an inner plexiform (IPL) and ganglion cell layers exhibiting the properties of compression, luminance and spatial temporal filtering in the processing of visual information. The photoreceptor layer enhances the contrast visibility in the dark region and maintains the same in the bright regions. The OPL is modeled to enhance the contour of the image. The finer detail of the image is extracted by mathematically modeling the IPL. The ganglion cell layer is modeled using the Hodgkin-Huxley model to generate the spike train for the incoming information. The spike train was generated for color deficient individuals namely protanopia, deuteranopia, tritanopia and for individuals suffering from night blindness. Simulation results showed a spike train was generated only for a certain threshold stimulus value. The differences in spike pattern for a normal and visually impaired individual were studied. This may lead to a methodology for earlier diagnosis.

BACKGROUND: Impaired dark adaptation is an early functional indicator of vitamin A deficiency that may be prevented by regular dietary intake of foods containing provitamin A carotenoids.
OBJECTIVE: We tested the impact of provitamin A carotenoid-biofortified maize consumption (∼15 μg β-carotene/g) on dark adaptation in Zambian children.
METHODS: We used a cluster-randomized trial of children aged 4-8 y (n = 1024) in Mkushi District, Zambia, and compared the regular consumption (2 meals/d, 6 d/wk for 6 mo) of biofortified orange maize (OM) to white maize (WM). The primary outcome was the serum retinol response. In a random sample (n = 542), we used a digital pupillometer to test pre- and postintervention responses to graded light stimuli (-2.9 to 0.1 log cd/m2) in a dark-adapted state.
RESULTS: At baseline, 11.7% of the children had serum retinol <0.7 μmol/L, 14.4% had impaired dark adaptation (pupillary threshold ≥ -1.11 log cd/m2), and 2.3% had night blindness. The mean ± SD pupillary responsiveness to light stimuli was poorer at baseline in the OM group (16.1% ± 6.6%) than the WM group (18.1% ± 6.4%) (P = 0.02) but did not differ at follow-up (OM: 17.6% ± 6.5%; WM: 18.3% ± 6.5%). Among children with serum retinol <1.05 μmol/L at baseline, there was greater improvement in pupillary responsiveness in the OM group (2.2%; 95% CI: 0.1%, 4.3%) than the WM group (0.2%; 95% CI: -1.1%, 1.5%; P = 0.01), but there were no differences in children with adequate baseline status. We found no effect of treatment on pupillary threshold or night blindness.
CONCLUSIONS: The regular consumption of provitamin A carotenoid-biofortified maize increased pupillary responsiveness among children with marginal or deficient vitamin A status, providing evidence of a functional benefit to consuming this biofortified crop. This trial was registered at clinicaltrials.gov as NCT01695148.

BACKGROUND: Vitamin A Deficiency is a common form of micronutrient deficiency, globally affecting 33.3 % of preschool-age children. An estimated of 44.4 % of preschool children in Africa were at risk for vitamin A deficiency. In Ethiopia, vitamin A deficiency leads to 80,000 deaths a year and affects 61 % of preschool children. The aim of this study was to investigate the prevalence and associated factors with the night blindness, Bitot\'s spot and vitamin A intake among preschool children in rural area, Asgede-Tsimbla district, North Ethiopia.
METHODS: Community based cross sectional study was conducted from January 27 to March 7, 2014. A total 1230 preschool children were selected by systematic random sampling from 8 randomly selected kebelles (smallest administrative unit). Structured and pretested questionnaires adapted from relevant studies and WHO/FAO was for data collection. In addition, sex, age, and height were taken and filled to Emergency Nutrition Assessment (ENA) for Standardized Monitoring and Assessment of Relief and Transition (SMART) 2007 software to convert the nutritional data into Z-scores of the indices. The data was then transported to SPSS version 20. Bivariate and Multivariable binary logistic regressions were carried out to investigate the effect of each independent variable on the dependent variable. Statistical significance was set at p-value < 0.05.
RESULTS: The odds of Bitot\'s spots (1.46 %) and night blindness (1.22 %) were higher than the WHO Cut-off levels used to define a public health problem. The odds of night blindness was 4 times higher among children belonging to family size greater or equal to four [Adjusted Odds Ratio (AOR) = 4.18, 95 % CI = 1.15,15.3] and 6 times higher among children of illiterate mothers [AOR = 5.96 , 95 % CI = 1.33,26.69]. The odds of Bitot\'s spots was 5.35 times higher among children belonging to family size greater or more four [AOR =5.35; 95 % CI = 1.49, 19.2], 4.75 times higher among children of illiterate mothers [AOR = 4.75, 95 % CI =1.32, 17.18] and 6 times higher in males than females [AOR = 5.8, 95 % CI = 1.65, 20.46].
CONCLUSIONS: The study revealed that night blindness and Bitot\'s spots are major nutritional problems in the study area. The independent predictors of night blindness were mother illiteracy status and large family size and also for Bitot\'s spots were mother illiteracy status, male sex of child and large family size. Therefore, the need to increase educational level of mother, use of family planning of women and emphasis on male children and children from large family size by involving the Education sector, Health sector, (Federal Ministry of Health) FMOH and (Tigray Regional Health Bureau) TRHB is crucial.

OBJECTIVE: The objective of the present study is to evaluate the nutritional status of vitamin A through biochemical and functional indicators of pregnant women who underwent Roux-en-Y gastric bypass (RYGB) surgery compared to pregnant women who did not undergo this surgery.
METHODS: The present study is a cross-sectional study of the analytical type with pregnant women paired by age and prepregnancy body mass index (BMI). Group 1 (G1) comprised 80 pregnant women without previous submission to RYGB and group 2 (G2) by 40 pregnant women who previously underwent this surgery. We used high-performance liquid chromatography with UV detector for quantification of retinol and β-carotene, and the functional evaluation of vitamin A deficiency (VAD) was performed through standardized interview validated for pregnant women.
RESULTS: G1 mean age was 29.3 ± 5.3 and 30.8 ± 4.4 in G2. BMI mean prepregnancy found in G1 was 25.7 ± 3.2 and 26.8 ± 3.1 in G2, featuring overweight. Serum retinol and β-carotene means were significantly higher in G1 (1.8 ± 0.9; 87.4 ± 62.2) compared to G2 (0.99 ± 0.39; 22.7 ± 18.0), respectively (p < 0.001). Regarding the functional indicator for evaluation of VAD, approximately 75.0 % of pregnant women in G2 showed night blindness and 20.0 % in G1, and the percentage of pregnant women with this functional impairment was significantly higher in G2 compared to G1 with p < 0.001.
CONCLUSIONS: Results show that pregnancy after RYGB can represent a high-risk situation for VAD. We recommend interdisciplinary monitoring added to the prenatal routine consultations and the conduction of studies addressed to the investigation of a safe and effective dose of oral supplementation of vitamin A to pregnant women undergoing RYGB.