Acquired subretinal flecks secondary to hypovitaminosis A in a patient with hepatitis C

Bilateral compressive optic neuropathy and outer retinopathy due to optic canal hyperostosis in a child with isolated vitamin a deficiency

PURPOSE

Vitamin A plays a crucial role in rod phototransduction, with deficient levels manifesting as night blindness. Animal models have demonstrated bone dysplasia in the setting of hypovitaminosis A. We present a rare case of bony overgrowth leading to bilateral compressive optic neuropathy, combined with outer retinopathy, in a paediatric patient secondary to isolated vitamin A deficiency.

METHODS

A single case report was conducted from Toronto, Canada.

RESULTS

A 12-year-old boy with known autism spectrum disorder presented with a 9-month history of progressive painless vision loss. Vision was 20/300 and hand motion in the right and left eye, respectively. Fundus photography demonstrated bilateral optic atrophy and yellow lesions notably in the right eye far periphery. Optical coherence tomography (OCT) imaging demonstrated thinning of the retinal nerve fibre layer, alterations in the ellipsoid zone, as well as retinal pigment epithelium deposits. Computed tomography imaging demonstrated sphenoid bone thickening with narrow optic canals and moderate optic atrophy bilaterally. Full-field electroretinogram (ERG) demonstrated mildly reduced dark adapted (DA) 0.01 b-wave amplitudes and electronegative configuration of DA 3.0 and DA 10.0 ERG; the light adapted ERGs were normal. The patient was treated with pulse vitamin A therapy. Subsequently, the DA ERG normalized, outer retinal changes reversed and vision stabilised; no surgical intervention was conducted.

CONCLUSION

This case represents a rare presentation of compressive optic neuropathy with concomitant outer retinopathy secondary to isolated vitamin A deficiency. Despite improvement in outer retinal integrity on OCT imaging and ERG testing results following vitamin A supplementation, no functional improvement was obtained due to severe optic atrophy.

Subretinal Drusenoid Deposit Formation: Insights From Turing Patterns

Purpose

The purpose of this study was to demonstrate that the organized formation of subretinal drusenoid deposits (SDDs) may be a Turing pattern.

Methods

A Java-based computational model of an inferred reaction-diffusion system using paired partial differential equations was used to create topographic images. Reaction kinetics were varied to illustrate a spectrum of pattern development, which were then compared to dot-like, reticular, and confluent SDD patterns observed clinically.

Results

A reaction-diffusion system using two agents, one an “activator” that increases its own production, and the other an “inhibitor” that decreases the activator's production, can create patterns that match the spectrum of topographic appearance of organized SDD. By varying a single parameter, the strength of the activator, the full spectrum of clinically observed SDD patterns can be generated. A new pattern, confluence with holes, is predicted and identified in one case example.

Conclusions

The formation of clinically significant SDD and its different patterns can be explained using Turing patterns obtained by simulating a two-component reaction-diffusion system.

Translational Relevance

This model may be able to guide future risk stratification for patients with SDD, and provide mechanistic insights into the cause of the disease.

Vitamin A deficiency after prolonged intake of an unbalanced diet in a Japanese hemodialysis patient

BACKGROUND

In industrialized countries, vitamin A deficiency (VAD) is extremely rare, except association with bariatric surgeries and hepatobiliary disorders. It is unusual that VAD develops during hemodialysis due to reduced glomerular filtration of vitamin A-binding protein. We reported the case of a 58-year-old Japanese male hemodialysis patient diagnosed with VAD.

CASE PRESENTATION

The patient undergoing hemodialysis for more than 15 years presented with progressive photophobia and night blindness and was ophthalmologically examined. He denied a history of cancer or hepatobiliary disease and reported that he loved eating prepackaged noodle bowls and foods, with prolonged low intake of fruits/vegetables. He had good visual acuity. Fundus images showed numerous white dots in the midperipheral retinae, but no degenerative changes. In baseline full-field electroretinography (ERG), b-wave responses were extremely reduced in rod ERG, a-wave amplitudes in standard-flash/strong-flash ERG were reduced to 20-25% of our controls, a- and b-wave amplitudes in cone ERG were reduced to 40-50% of the controls. Whole-exome sequencing identified no pathogenic variant for any inherited retinal disorder. He was diagnosed with VAD because of reduced serum vitamin A levels and treated with retinol palmitate. Two months after treatment commencement, the serum vitamin A level was within the normal range. Full-field ERG showed that the scotopic ERG responses markedly improved compared with baseline.

CONCLUSIONS

This is the first report of VAD associated with undernutrition in the Japanese hemodialysis population.

Late-onset night blindness with peripheral flecks accompanied by progressive trickle-like macular degeneration

PURPOSE

To report the clinical and genetic characteristics of 6 cases with late-onset night blindness with peripheral flecks accompanied by progressive trickle-like macular degeneration.

METHODS

Clinical and genetic data were collected from 6 independent patients who complained of night blindness in their fifth to eighth decade of life. The ophthalmological examinations included ophthalmoscopy, fundus autofluorescence (FAF), and full-field electroretinography (ERG). Whole exome sequencing with target gene analysis was performed to determine the causative genes and variants.

RESULTS

All of the patients first complained of night blindness at the ages of 40-71 years. Funduscopic examinations demonstrated white or atrophic flecks scattered in the posterior pole and peripheral retina bilaterally. FAF showed patchy hypo-autofluorescence spots in the posterior pole similar to that of the trickling type of age-related macular degeneration (AMD). The region of abnormal FAF rapidly expanded with age, and one eye developed a choroidal neovascularization. The full-field scotopic ERGs with 20 min of dark adaptation were severely reduced or extinguished in all cases. There was partial recovery of the ERGs after 180 min of dark adaptation. The cone ERGs were reduced in all cases. Whole exome sequencing revealed no pathogenic variants of 301 retinal disease-associated genes.

CONCLUSIONS

The six cases had some common features with the flecked retina syndrome, familial drusen, and late-onset retinal degeneration although none had pathogenic variants causative for these disorders. These cases may represent a subset of severe trickling AMD or a new clinical entity of acquired pan-retinal visual cycle deficiency of unknown etiology.

Subretinal drusenoid deposits AKA pseudodrusen

A distinction between conventional drusen and pseudodrusen was first made in 1990, and more recently knowledge of pseudodrusen, more accurately called subretinal drusenoid deposits (SDDs), has expanded. Pseudodrusen have a bluish-white appearance by biomicroscopy and color fundus photography. Using optical coherence tomography, pseudodrusen were found to be accumulations of material internal to the retinal pigment epithelium that could extend internally through the ellipsoid zone. These deposits are more commonly seen in older eyes with thinner choroids. Histologic evaluation of these deposits revealed aggregations of material in the subretinal space between photoreceptors and retinal pigment epithelium. SDDs contain some proteins in common with soft drusen but differ in lipid composition. Many studies reported that SDDs are strong independent risk factors for late age-related macular degeneration. Geographic atrophy and type 3 neovascularization are particularly associated with SDD. Unlike conventional drusen, eyes with SDD show slow dark adaptation and poor contrast sensitivity. Outer retinal atrophy develops in eyes with regression of SDD, a newly recognized form of late age-related macular degeneration. Advances in imaging technology have enabled many insights into this condition, including associated photoreceptor, retinal pigment epithelium, and underlying choroidal changes.

Recurrent episodes of night blindness in a patient with short bowel syndrome

PURPOSE

To describe clinical characteristics in a patient with recurrent episodes of night blindness due to vitamin A deficiency caused by short bowel syndrome in Crohn disease.

METHODS

Retrospective analysis of best-corrected visual acuity (BCVA), kinetic perimetry, slit-lamp biomicroscopy, ophthalmoscopy, fundus photography, fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), dark adaptometry (DA) and electroretinography (ERG). Serum vitamin A level was measured.

RESULTS

A 44-year-old man with a 3-year history of night blindness suffered from a short bowel syndrome with chronic malabsorption due to ileocecal resection in Crohn disease. Both eyes had a BCVA of 0.9, Bitot's spots of the conjunctiva and no significant fundus abnormalities. SD-OCT showed no remarkable changes, whereas FAF was brighter than normal in the center of the fovea. DA showed normal cone and a lack of rod function. The dark-adapted 0.01 ERG was non-detectable, the dark-adapted 3.0 ERG severely diminished, but the light-adapted 3.0 and 30 Hz flicker ERGs were within normal limits. Serum vitamin A level was 0.11 µg/ml (normal 0.30-0.65 µg/ml). Treatment with intravenous vitamin A caused a rapid recovery of night vision and ERG. However, during the following 3 years, he had three further episodes of night blindness with loss of rod function. During each period, parenteral vitamin A substitution brought complete recovery of night vision and rod function. BCVA, fundus, FAF findings and SD-OCT remained unchanged during the course.

CONCLUSIONS

In patients with known chronic malabsorption serum vitamin A level should be regularly checked to avoid recurrent night blindness episodes. ERG might be more sensitive than serum vitamin A level and is recommended in case of night blindness but still normal vitamin A level.

Acquired night blindness due to bad eating patterns

We report a case of acquired night blindness in a developed country (Spain) without risk factors for nutritional deficiency disease or family history of hereditary retinal disease. A 76-year-old woman presented with acquired night blindness of 6-month progression. After a thorough inquiry about eating patterns she becomes suspicious of vitamin A low dietary intake, which is analytically confirmed and successfully treated. Despite being very uncommon in our environment and even more in patients without digestive problems, in a patient reporting acquired night blindness vitamin A deficiency should not be discarded until eating patterns have been investigated. It might be especially relevant in certain socioeconomic situations and eating disorders such as bulimia or anorexia nervosa.

Electrophysiological and microperimetry changes in vitamin A deficiency retinopathy

PURPOSE

To describe a follow-up case of vitamin A deficiency (VAD)-related retinopathy with macular involvement monitored with electroretinography and microperimetry.

METHODS

Flash (ERG), pattern (PERG), and multifocal (mfERG) electroretinography were recorded in parallel with microperimetry before and during 7-month follow-up of vitamin A treatment on a 65-year-old man presented with a 1-year history of night blindness. The patient had undergone ileostomy procedure for Crohn's disease 14 years ago. His best corrected visual acuity was 6/6 in each eye. Fundus examination revealed macular and mid-peripheral yellow-white lesions compatible with drusen.

RESULTS

Before treatment, PERG was reduced, and mfERG was reduced and delayed, worse in responses from the central rings. These results revealed evidence of bilateral macular and central cone dysfunction. The flash ERG showed reduced dark-adapted 0.01 ERG (rod response); a-wave of dark-adapted 3.0 and 10.0 ERG was normal but b-wave was reduced (negative configuration); light-adapted 3.0 ERG was slightly reduced. The flash ERG revealed evidence of bilateral generalised retinal dysfunction affecting the rod more than cone system. Microperimetry showed deep reduction in retinal sensitivity. Fixation stability was unstable with eccentric locus. During treatment, ERG and microperimetry demonstrated significant improvements. Fixation stability reached normal values after the third treatment week.

CONCLUSIONS

This case illustrates the importance of electrophysiological investigation in early VAD-related retinopathy detection correlated with microperimetry. Our findings indicate a more delayed central cone function recovery than that of generalised rod and cone function. There was a marked correlation between ERG and microperimetric changes.

Pseudodrusen subtypes as delineated by multimodal imaging of the fundus

PURPOSE

To subclassify pseudodrusen based on their appearance in multimodal imaging.

DESIGN

Retrospective, observational series.

METHODS

The color fundus photographs and infrared scanning laser ophthalmoscope (IR-SLO) images of patients with pseudodrusen were evaluated along with spectral-domain optical coherence tomography (SD OCT) by masked readers. Distinct types of pseudodrusen could be differentiated.

RESULTS

There were 140 eyes of 93 patients with a mean age of 82.4 years. Multimodal imaging analysis showed 3 subtypes of pseudodrusen. One principal type was an orderly array of whitish discrete accumulations principally located in the perifovea, termed dot pseudodrusen. They appeared as hyporeflective spots, often with a target configuration, in IR-SLO images. The second type was interconnected bands of yellowish-white material forming a reticular pattern, called ribbon pseudodrusen, which were located in the perifovea. This subtype was faintly hyporeflective in IR-SLO imaging. Dot pseudodrusen were detected more commonly with IR-SLO imaging than in color photography (P = .014) and ribbon pseudodrusen were seen more frequently in color than in IR-SLO images (P < .001). An uncommon third type of pseudodrusen, yellow-white globules primarily located peripheral to the perifoveal region, appeared hyper-reflective in IR-SLO and were called peripheral pseudodrusen. All 3 types were seen as subretinal drusenoid deposits by SD OCT.

CONCLUSION

Pseudodrusen may be classified into at least 3 categories, each with optimal methods of detection and only 1 that formed a reticular pattern. These findings suggest pseudodrusen could contain differing constituents and therefore may vary in conferred risk for progression to advanced age-related macular disease.

Fundus white spots and acquired night blindness due to vitamin A deficiency

To report a successfully treated case of acquired night blindness associated with fundus white spots secondary to vitamin A deficiency. An ocular examination, electrophysiologic testing, as well as visual field and OCT examinations were obtained on a 61-year-old man with vitamin A deficiency who had previously undergone gastric bypass surgery. The patient had a re-evaluation after treatment with high doses of oral vitamin A. The patient was observed to have numerous white spots in the retina of each eye. Best-corrected visual acuity was initially 20/80 in each eye, which improved to 20/40-1 OU after oral vitamin A therapy for 2 months. Full field electroretinogram (ERG) testing, showed non-detectable rod function and a 34 and 41% reduction for 32-Hz flicker and single flash cone responses, respectively, below the lower limits of normal. Both rod and cone functions markedly improved after initiation of vitamin A therapy. Vitamin A deficiency needs to be considered in a patient with white spots of the retina in the presence of poor night vision.