Complete congenital stationary night blindness associated with a novel NYX variant (p.Asn216Lys) in middle-aged and older adult patients.

BACKGROUND: Complete congenital stationary night blindness (CSNB) is a retinal disorder thought to be non-progressive. The purpose of this study was to characterize the clinical and genetic findings of middle-aged and older adult patients with X-linked complete CSNB. METHODS: Three male CSNB patients (aged 62, 72, and 51 years) and one unaffected female carrier in a Japanese family were included in this study. Whole-exome sequencing (WES) was performed to determine the disease-causing variants. Co-segregation was confirmed in the family members. We performed a comprehensive ophthalmic examination on each patient. RESULTS: In the 62-year-old patient, a novel hemizygous variant (c.648 C > A; p.Asn216Lys) of the NYX gene was identified by WES analysis. The other two patients carried the variant hemizygously, and the unaffected carrier harbored the variant heterozygously. The clinical and electroretinography (ERG) findings were very similar among all three patients. Fundus images exhibited high myopic chorioretinal atrophy with long axial length. Ultra-wide field fundus autofluorescence images showed no retinal degenerative changes except for changes resulting from high myopia and previous retinal diseases. The ERG findings showed no response in rod ERG, electronegative configuration with preserved a-waves in standard/bright-flash ERG, and preserved responses in cone and 30-Hz flicker ERG, which were compared with age-matched controls with high myopia. CONCLUSIONS: We identified a novel missense NYX variant in a Japanese family with complete CSNB. Our clinical findings indicated that photoreceptor mediated ERG responses are well preserved even in middle-aged and older adult patients.

Restoration of mGluR6 Localization Following AAV-Mediated Delivery in a Mouse Model of Congenital Stationary Night Blindness.

Purpose: Complete congenital stationary night blindness (cCSNB) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. GRM6 mutations are the third most prevalent cause of cCSNB. The Grm6-/- mouse model mimics the human phenotype, showing no b-wave in the electroretinogram (ERG) and a loss of mGluR6 and other proteins of the same cascade at the outer plexiform layer (OPL). Our aim was to restore protein localization and function in Grm6-/- adult mice targeting specifically ON-BCs or the whole retina. Methods: Adeno-associated virus-encoding Grm6 under two different promoters (GRM6-Grm6 and CAG-Grm6) were injected intravitreally in P15 Grm6-/- mice. ERG recordings at 2 and 4 months were performed in Grm6+/+, untreated and treated Grm6-/- mice. Similarly, immunolocalization studies were performed on retinal slices before or after treatment using antibodies against mGluR6, TRPM1, GPR179, RGS7, RGS11, Gß5, and dystrophin. Results: Following treatment, mGluR6 was localized to the dendritic tips of ON-BCs when expressed with either promoter. The relocalization efficiency in mGluR6-transduced retinas at the OPL was 2.5% versus 11% when the GRM6-Grm6 and CAG-Grm6 were used, respectively. Albeit no functional rescue was seen in ERGs, relocalization of TRPM1, GPR179, and Gß5 was also noted using both constructs. The restoration of the localization of RGS7, RGS11, and dystrophin was more obvious in retinas treated with GRM6-Grm6 than in retinas treated with CAG-Grm6. Conclusions: Our findings show the potential of treating cCSNB with GRM6 mutations; however, it appears that the transduction rate must be improved to restore visual function.

Clinical and genetic investigations of three Moroccan families with retinitis pigmentosa phenotypes.

Purpose: Progressive inherited retinal dystrophies, characterized by degeneration of rod photoreceptors and then cone photoreceptors, are known as retinitis pigmentosa (RP), for which 89 genes have been identified. Today, only five Moroccan families with RP with a genetic diagnosis have been reported, justifying our investment in providing further clinical and genetic investigations of families with RP in Morocco. Methods: The clinical diagnosis based on a combination of a history of night blindness, abnormal rod or rod-cone responses in electroretinography (ERG), and constricted visual field or difficulty perceiving side objects identified three Moroccan families with an RP phenotype. Probands of these families underwent whole exome sequencing (WES), and candidate variants were evaluated for their segregation within family members. Results: All patients had a history of night blindness and unrecordable rod and cone ERG traces. In addition, one patient had cystoid macular edema, and another had discrete autofluorescence abnormalities, in addition to ellipsoid zone disorganization and narrowed retinal vessels. WES sequencing revealed heterozygous compound mutations in CRB1:c.1690G>T//c.1913C>T and in ABCA4:c.5908C>T//c.6148G>C and a homozygous PDE6B splice mutation c.1920+2T>C. Conclusions: We provide the first description of Moroccan patients with the RP phenotype harboring pathogenic mutations in the CRB1 and ABCA4 genes and the second description of an individual with RP with a PDE6B mutation, associated with cystoid macular edema. These data contribute to expand the genetic diagnosis of RP phenotypes in Morocco.

Efavirenz-Associated Retinal Toxicity Presenting with Night Vision Defects in Patients with Human Immunodeficiency Virus.

Ocular lesions in patients with human immunodeficiency virus (HIV) are commonly due to underlying opportunistic infections. With highly active antiretroviral therapy (HAART), infectious lesions have reduced and noninfectious ocular manifestations including drug-related side effects have been noted. While retinal toxicity has been noted with few other HAART drugs, there are not many on the same with Efavirenz usage. We report a series of five patients with possible efavirenz-related retinal toxicity, visual function abnormalities, and its management. Efavirenz was replaced with alternate anti-retroviral drug. Reversal of ocular side effects were noted subjectively in the form of symptom amelioration of the patients. Objectively, it could be documented with electroretinogram changes and other visual function tests reverting back to normal after change in HAART regime. Early identification of this uncommon side effect in select patients can prevent irreversible vision loss due to efavirenz-associated retinal toxicity.

Electronegative Electroretinograms in the United Arab Emirates.

PURPOSE: An electronegative electroretinogram (ERG), defined as having a b:a wave ratio ≤1 in the scotopic flash ERG response, indicates relative inner retinal dysfunction. Causes vary depending upon the study population. In the Arabian Gulf, where inherited retinal disease is relatively prevalent, common diagnoses associated with electronegative ERGs have not been described. In this study, we report the frequency and causes of electronegative ERGs in a cohort of Emirati patients with inherited retinal disease. METHODS: A retrospective review was performed of all full-field ERGs done for Emirati patients in the Ocular Genetics Service of Cleveland Clinic Abu Dhabi from January 2017 to December 2019. Those who had an electronegative ERG in at least one eye were included in the study. RESULTS: Out of 137 patients, 9 probands (6.6%) had an electronegative ERG. The mean age at presentation was 24 years (range 5-48 years), and five patients (55.6%) were male. The final clinical diagnoses were congenital stationary night blindness (CSNB) (two TRPM1-related and one Oguchi disease), X-linked retinoschisis (XLRS) (one genetically confirmed and two not genetically tested), cone-rod dystrophy (one CRX-related and one not genetically tested), and enhanced S-cone syndrome (ESCS) (one NRL-related). The one patient who did not have bilateral electronegative ERGs was a male with XLRS whose fellow eye had an unrecordable ERG. CONCLUSIONS: In this series of Emirati patients, an electronegative ERG was most commonly associated with the inherited retinal diseases recessive CSNB and XLRS. An electronegative ERG was noted in a case of NRL-related ESCS.

Night Blindness in a Healthy Middle-Class Child.

How do you clinically approach a night-blind child in a vegetarian family, with no obvious dystrophy and no obvious malnutrition? This case reviews some of the issues, and it reminds us of some of the cautions. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:286-288.].

Differential adaptations in rod outer segment disc membranes in different models of congenital stationary night blindness.

Rod photoreceptor cells initiate scotopic vision when the light receptor rhodopsin absorbs a photon of light to initiate phototransduction. These photoreceptor cells are exquisitely sensitive and have adaptive mechanisms in place to maintain optimal function and to overcome dysfunctional states. One adaptation rod photoreceptor cells exhibit is in the packing properties of rhodopsin within the membrane. The mechanism underlying these adaptations is unclear. Mouse models of congenital stationary night blindness with different molecular causes were investigated to determine which signals are important for adaptations in rod photoreceptor cells. Night blindness in these mice is caused by dysfunction in either rod photoreceptor cell signaling or bipolar cell signaling. Changes in the packing of rhodopsin within photoreceptor cell membranes were examined by atomic force microscopy. Mice expressing constitutively active rhodopsin did not exhibit any adaptations, even under constant dark conditions. Mice with disrupted bipolar cell signaling exhibited adaptations, however, they were distinct from those in mice with disrupted phototransduction. These differential adaptations demonstrate that although multiple molecular defects can lead to a similar primary defect causing disease (i.e., night blindness), they can cause different secondary effects (i.e., adaptations). The lighting environment or signaling defects present from birth and during early rearing can condition mice and affect the adaptations occurring in more mature animals. A comparison of effects in wild-type mice, mice with defective phototransduction, and mice with defective bipolar cell signaling, indicated that bipolar cell signaling plays a role in this conditioning but is not required for adaptations in more mature animals.

Oguchi disease caused by a homozygous novel SAG splicing alteration associated with the multiple evanescent white dot syndrome: A 15-month follow-up.

PURPOSE: We report a 15-month follow-up case on a Chinese patient with Oguchi disease associated with the multiple evanescent white dot syndrome (MEWDS). METHODS: The patient's clinical presentation and follow-up visits were documented via decimal best-corrected visual acuity, fundus photography, fundus autofluorescence (FAF) imaging, near-infrared FAF, spectral domain optical coherence tomography, Humphrey's visual fields, microperimetry, and multifocal electroretinography. We also performed whole exome sequencing for screening variation in the patient and her relatives. RESULTS: The patient had typical clinical characteristic of Oguchi disease, including night blindness, the Mizuo-Nakamura phenomenon (a golden yellow discoloration of the fundus that disappears in the prolonged dark adaptation [DA]) and typical full-field electroretinogram changes (nearly undetected b-wave in 0.01 and 0.03 ERGs that can partially recover only after prolonged DA). Aside from Oguchi disease, the patient was also diagnosed with the MEWDS based on clinical detections, including suddenly reduced visual acuity, appeared white dots, blurred ellipsoid zone and disrupted interdigitation zone, enlarged blind spot, and reduced macular sensitivity. A series of investigations revealed that along with the 15-month follow-up after onset, the visual acuity enhanced, the numerous white dots disappeared, and the macular structure returned to normal. Moreover, the novel homozygous splicing alteration c.181 + 1G > A was identified in the SAG gene. CONCLUSIONS: This work is the first long-term case study of a patient with Oguchi disease associated with the MEWDS. The recovery period of symptoms caused by the MEWDS was much longer than that in typical patients with MEWDS. Molecular genetics demonstrate that this is the first case of Oguchi disease caused by splicing alterations in the SAG gene.

Wide-field true-colour imaging and clinical characterization of a novel GRK1 mutation in Oguchi disease.

PURPOSE: The available literature regarding Oguchi disease is limited, with around 50 cases described to date. Caused by mutations to either the SAG gene coding for arrestin (Hayashi et al. in Ophthalmic Res 46:175-180, 2011) or the GRK1 gene coding for rhodopsin kinase (Yamamoto et al. in Nat Genet 15:175-178. https://doi.org/10.1038/ng0297-175 , 1997), Oguchi disease is an autosomal recessive condition with a good visual prognosis. The clinical diagnosis of the condition is based on the presence of night blindness (nyctalopia), as well as fundoscopic observation of the Mizuo-Nakamura phenomenon. The Mizuo-Nakamura phenomenon refers to a fundus discolouration described as a golden-brown colour with a yellow-grey metallic sheen most prominent in the peripheral retina; after prolonged dark adaptation, the fundus appears normal. The prevalence of Oguchi disease is highest in Japan, particularly with SAG mutations (Nakazawa et al. in Retina 17:17-22, 1997), although patients from Europe, Pakistan and India have also been described. Formal diagnosis requires genetic testing. METHODS: Wide-field fundus images were obtained in both dark-adapted and light-adapted retina. Optical coherence tomography and dark-adapted electroretinography responses were used to further characterize the clinical phenotype. RESULTS: Existing descriptions of Oguchi disease have been limited by available technology. The flashes required for 45°-montage photographs in a dark-adapted eye quickly cause light adaptation. Recent advances in technology enable the capture of larger retinal areas in a single image. Wide-field 133° images were obtained of the native and dark-adapted fundus in natural colour. To our knowledge, these represent the first reported single-wide-field images of Oguchi disease, showing the characteristic Mizuo-Nakamura phenomenon in true colour. Genetic testing revealed a novel homozygous mutation in GRK1. CONCLUSIONS: Here, we demonstrate how characterizing this condition with single-shot true-colour wide-field imaging has distinct advantages over scanning laser technology, which applies artificial colouration, or stitched true-colour images. Images captured with wide-field systems create a much better representation of the native and dark-adapted fundus than can be observed by the ophthalmologist using direct fundoscopy and are essential in the clinical characterization of new mutations.

Ring analysis of multifocal oscillatory potentials (mfOPs) in cCSNB suggests near-normal ON-OFF pathways at the fovea only.

PURPOSE: To investigate the center-periphery distribution of ON and OFF retinal responses in complete congenital stationary night blindness (cCSNB). METHODS: Photopic full-field flash ERGs (photopic ffERGs) and OPs (photopic ffOPs) and slow m-sequence (to enhance OP prominence) mfERGs (and filtered mfOPs) evoked by a 37 hexagon stimulus array were recorded from normal subjects and cCSNB patients. Discrete wavelet transform (DWT) analysis of photopic ffERGs and mfERGs was also performed in order to assess the contribution of the ON and OFF retinal pathways (i.e., OFF-to-ON ratio) in both cohorts. RESULTS: As expected, the photopic ffERG (and ffOPs) responses in cCSNB were devoid of the first two of the three OPs (i.e., OP2 and OP3 and OP4) normally seen on the ascending limb of the b-wave. A similar finding was also noted in the mfERGs (and mfOPs) of ring 4. In contrast, the mfERGs (and mfOPs) of ring 1 included all three OPs. DWT analysis revealed that while in normal subjects, the OFF-to-ON ratio of mfERGs slightly increased from rings 1 to 4 (from 0.61 ± 0.03 to 0.78 ± 0.04; p < 0.05; median: from 0.62 to 0.79; p < 0.05), in cCSNB this ratio increased significantly more [from 0.73 ± 0.13 (ring 1) to 1.18 ± 0.17 (ring 4); p < 0.05; median: 0.78 to 1.22; p < 0.05], hence from a normal ON-dominated ratio (central ring) to an OFF-dominated ratio (peripheral ring). CONCLUSIONS: Our results show a clear discrepancy of ON and OFF mfOP components in cCSNB. Responses originating from the most central ring (i.e., ring 1) disclosed a near-normal electrophysiological contribution (as revealed with the presence of OP2, OP3 and OP4 as well as with the DWT OFF-to-ON ratio) of the retinal ON and OFF pathways in mfERG (and mfOPs) responses compared to responses from the more peripheral ring (and ffOP) which are devoid of the ON OPs (i.e., OP2 and OP3).

Visual snow syndrome: A clinical and phenotypical description of 1,100 cases.

OBJECTIVE: To validate the current criteria of visual snow and to describe its common phenotype using a substantial clinical database. METHODS: We performed a web-based survey of patients with self-assessed visual snow (n = 1,104), with either the complete visual snow syndrome (n = 1,061) or visual snow without the syndrome (n = 43). We also describe a population of patients (n = 70) with possible hallucinogen persisting perception disorder who presented clinically with visual snow syndrome. RESULTS: The visual snow population had an average age of 29 years and had no sex prevalence. The disorder usually started in early life, and ≈40% of patients had symptoms for as long as they could remember. The most commonly experienced static was black and white. Floaters, afterimages, and photophobia were the most reported additional visual symptoms. A latent class analysis showed that visual snow does not present with specific clinical endophenotypes. Severity can be classified by the amount of visual symptoms experienced. Migraine and tinnitus had a very high prevalence and were independently associated with a more severe presentation of the syndrome. CONCLUSIONS: Clinical characteristics of visual snow did not differ from the previous cohort in the literature, supporting validity of the current criteria. Visual snow likely represents a clinical continuum, with different degrees of severity. On the severe end of the spectrum, it is more likely to present with its common comorbid conditions, migraine and tinnitus. Visual snow does not depend on the effect of psychotropic substances on the brain.

Electroretinographic abnormalities associated with pregabalin: a case report.

PURPOSE: Pregabalin binds to the α2-δ1/α2-δ2 subunits of the voltage-gated L-type calcium channel (LTCC), which is expressed in rod/cone photoreceptor terminals. The purpose of this report was to describe electroretinographic abnormalities associated with pregabalin treatment. CASE PRESENTATION: This is an observational case report. A 49-year-old female reported photophobia and night blindness in her left eye after 10 months of pregabalin administration. One month after the symptoms, ophthalmic examinations were performed, which revealed good visual acuity and no remarkable fundus findings. However, full-field electroretinography (ERG) of the left eye revealed a decreased b-wave in rod ERG, a slightly decreased a-wave and severely decreased b-wave (negative ERG) in bright flash ERG, decreased a- and b-waves in cone ERG, and decreased b-waves in 30-Hz flicker ERG. These findings are similar to those seen in incomplete congenital stationary night blindness, whereas the right eye ERG showed normal responses, except for a square a-wave in cone ERG. The ERG gradually improved from 1 to 12 months after discontinuing pregabalin. Finally, b-waves in bright flash ERG and cone ERG responses largely recovered, but b-waves in rod ERG and a-waves in bright flash ERG only partially recovered in the left eye. The square a-wave recovered to normal in the right eye. CONCLUSIONS: This is the first report to indicate that ERG abnormalities might be associated with pregabalin treatment. Our results suggest that pregabalin may affect LTCC function via the α2-δ1/α2-δ2 subunits, which leads to defective synaptic transmission from rod/cone photoreceptors to bipolar cells.

Coexistence of GNAT1 and ABCA4 variants associated with Nougaret-type congenital stationary night blindness and childhood-onset cone-rod dystrophy.

PURPOSE: A single variant (p.G38D) in the GNAT1 gene, encoding the rod-specific transducin α-subunit in phototransduction, has been reported only in one French family with Nougaret-type autosomal dominant congenital stationary night blindness (CSNB). We identified a Japanese family with Nougaret-type CSNB and cone-rod dystrophy (CORD). METHODS: Five patients with CSNB and two patients with childhood-onset CORD were recruited. We performed a comprehensive ophthalmic examination including electroretinography (ERG). Disease-causing variants were identified by whole exome sequencing, with candidates confirmed by Sanger sequencing in nine family members. RESULTS: The GNAT1 variant (p.G38D) was identified in all four CSNB patients, whereas the two CORD patients carried biallelic truncated known ABCA4 variants as well as the GNAT1 variant. Clinically, no remarkable findings were observed in fuduscopy, fundus autofluorescence, or optical coherence tomography images from the CSNB patients. No response was detectable by rod ERG. The a-waves of standard and bright flash ERG were delayed and broadened rather than biphasic, and b/a-wave amplitude ratio was negative. Cone and 30-Hz flicker responses were normal, and overall, the ERG findings were compatible with previous descriptions of Nougaret-type CSNB. ERG of the CORD patients with macular atrophy showed non-recordable rod response and severely decreased standard flash, cone and 30-Hz flicker responses. CONCLUSIONS: This is the second report of a Nougaret-type CSNB family with the GNAT1 variant. Our novel findings suggest that coexistence of the GNAT1 and biallelic ABCA4 variants is associated with an overlapping phenotype with both Nougaret-type CSNB and CORD.

Verifying complaints of difficulties in night vision using electroretinography and dark adaptation tests.

PURPOSE: To determine the electroretinographical and psychophysical parameters that can help to verify patients' complaints of reduced night vision. METHODS: We tested 275 consecutive patients with normal appearing fundi, complaining of visual difficulties at night, using flash electroretinography (ERG) and dark adaptation (DA) test. Two ERG parameters were used to assess a scotopic retinal function: the amplitude of the response to dim blue flash (the rod response) and the b-wave ratio (measured/expected). Dark adaptation was measured with green- and red-light stimuli after exposure to a bright, bleaching light. The psychophysical parameter of night vision was defined as the threshold for detection of the blue-green stimulus that was measured after 40-45 min in complete darkness. RESULTS: Fifty-five patients were excluded from the analysis because of a discrepancy between the two ERG parameters in assessment of scotopic retinal function. The remaining 220 patients were divided into 4 groups: (1) normal ERG and normal DA, (2) subnormal ERG and subnormal DA, (3) normal ERG and subnormal DA and (4) subnormal ERG and normal DA. The ERG and DA tests supported the complaint of visual difficulties at night in 67 patients (group 2), while 34 patients were characterized as having normal scotopic visual function (group 1). The other 119 patients (groups 3 and 4) presented a diagnostic dilemma because one test (ERG or dark adaptation) showed normal scotopic function, while the other indicated subnormal scotopic function. CONCLUSION: Our findings indicate that ERG is an essential, but not sufficient test for verifying patient's complaint on visual difficulties in the dark. We suggest using both electroretinography and psychophysical dark adaptation to test patients complaining of reduced night vision.

Extracting the ON and OFF contributions to the full-field photopic flash electroretinogram using summed growth curves.

Under cone-mediated (photopic) conditions, an "instantaneous" flash of light, including both stimulus onset and offset, will simultaneously activate both "ON" and "OFF" bipolar cells, which either depolarize (ON) or hyperpolarize (OFF) in response and, respectively, produce positive-going and negative-going deflections in the electroretinogram (ERG). The stimulus-response (SR) relationship of the photopic ON response demonstrates logistic growth, like that manifested in the rod-mediated (scotopic) b-wave, which is driven by a single class of depolarizing bipolar cell. However, the photopic b-wave SR function is importantly shaped by OFF responses, leading to a "photopic hill." Furthermore, both on and off stimuli elicit activity in both ON and OFF bipolar cells. This has made it difficult to produce meaningful parameters for ready interpretation of the photopic b-wave SR relationship. Therefore, we evaluated whether the sum of sigmoidal SR functions, as descriptors of the depolarizing and hyperpolarizing components of the photopic flash ERG, could be used to elucidate and quantitate the mechanisms that produce the photopic hill. We used a novel fitting routine to optimize a sum of simple sigmoidal curves to SR data in five groups of subjects: Healthy adult, 10-week-old infant, congenital stationary night blindness (CSNB), X-linked juvenile retinoschisis (XJR), and preterm-born, both without and with a history of retinopathy of prematurity (ROP). Differences in ON and OFF amplitude, sensitivity, and implicit time among the groups were then compared using parameters extracted from these fits. We found that our modeling procedure enabled plausible derivations of ON and OFF pathway contributions to the ERG, and that the parameters produced appeared to have physiological relevance. In adult subjects, the ON and OFF amplitudes were similar in magnitude with respectively longer and shorter implicit times. Infant, CSNB, and XJR subjects showed significant ON pathway deficits. History of preterm-birth, without or with a diagnosis of ROP, did not much affect cone responses.

Nystagmus in patients with congenital stationary night blindness (CSNB) originates from synchronously firing retinal ganglion cells.

Congenital nystagmus, involuntary oscillating small eye movements, is commonly thought to originate from aberrant interactions between brainstem nuclei and foveal cortical pathways. Here, we investigated whether nystagmus associated with congenital stationary night blindness (CSNB) results from primary deficits in the retina. We found that CSNB patients as well as an animal model (nob mice), both of which lacked functional nyctalopin protein (NYX, nyx) in ON bipolar cells (BCs) at their synapse with photoreceptors, showed oscillating eye movements at a frequency of 4-7 Hz. nob ON direction-selective ganglion cells (DSGCs), which detect global motion and project to the accessory optic system (AOS), oscillated with the same frequency as their eyes. In the dark, individual ganglion cells (GCs) oscillated asynchronously, but their oscillations became synchronized by light stimulation. Likewise, both patient and nob mice oscillating eye movements were only present in the light when contrast was present. Retinal pharmacological and genetic manipulations that blocked nob GC oscillations also eliminated their oscillating eye movements, and retinal pharmacological manipulations that reduced the oscillation frequency of nob GCs also reduced the oscillation frequency of their eye movements. We conclude that, in nob mice, synchronized oscillations of retinal GCs, most likely the ON-DCGCs, cause nystagmus with properties similar to those associated with CSNB in humans. These results show that the nob mouse is the first animal model for a form of congenital nystagmus, paving the way for development of therapeutic strategies.

Night Blindness in Cystic Fibrosis: The Key Role of Vitamin A in the Digestive System.

Vitamin A is a fundamental micronutrient that regulates various cellular patterns. Vitamin A deficiency (VAT) is a worldwide problem and the primary cause of nocturnal blindness especially in low income countries. Cystic fibrosis (CF) is a known risk factor of VAD because of liposoluble vitamin malabsorption due to pancreatic insufficiency. We describe a case of a 9-year-old girl who experienced recurrent episodes of nocturnal blindness due to profound VAD. This little girl is paradigmatic for the explanation of the key role of the gut-liver axis in vitamin A metabolism. She presents with meconium ileus at birth, requiring intestinal resection that led to a transient intestinal failure with parenteral nutrition need. In addition, she suffered from cholestatic liver disease due to CF and intestinal failure-associated liver disease. The interaction of pancreatic function, intestinal absorption and liver storage is fundamental for the correct metabolism of vitamin A.

Novel findings in enhanced S-cone syndrome: a case with macular retinal neovascularization and severe retinal vasculitis.

PURPOSE: To describe a novel association of enhanced S-cone syndrome (ESCS) with macular retinal neovascularization and severe retinal vasculitis. METHODS: Clinical examination, spectral domain optical coherence tomography, fluorescein angiography, fundus autofluorescence, infrared reflectance and electroretinography were used to study a 25-year-old male with a history of night blindness from early childhood and recent accelerated visual loss in right eye. RESULTS: Pigmented lesions were observed along the arcades without peripheral retinal involvement. Intraretinal cystoid spaces, retinal neovascularization of posterior pole and severe peripheral and posterior retinal vasculitis were found on clinical examination and multimodal imaging. Based on characteristic clinical and electroretinographic findings, a diagnosis of ESCS was made. CONCLUSION: This case highlights novel associations of retinal neovascularization and vasculitis with ESCS.