Yoked prisms and cerebral visual impairment: Enhancing the experience of ambient vision.

BACKGROUND: Perceptual visual impairment leads to impaired functional vision in children with cerebral visual impairment. Yoked prisms have been used in behavioral vision therapy for children with autism (dysfunctional dorsal visual processing pathway) and in neurorehabilitation to treat visual neglect, hemianopia, and abnormal egocentric localization. In particular, they are employed for treating perceptual visual problems. PURPOSE: To share our experience in implementing yoked prisms and their impact on the rehabilitation of children with cerebral visual impairment-related perceptual vision disorders. SYNOPSIS: The first child with periventricular leukomalacia exhibits no eagerness to explore her new environment along with poor grasp. With 4-PD base-down prisms, she explores her surroundings and appreciates her lateral supports. Her grasp improved as well. The second child with cerebral visual impairment exhibits difficulty in climbing downstairs with poor obstacle negotiation. This could be due to impaired inferior field awareness or optic ataxia. With 4-PD base-down prisms, the field shift toward the apex helps him to climb downstairs without difficulty with an improved obstacle negotiation. The third child prefers a closer look at the object of interest along with poor hand-eye coordination. We employed 4-PD base-down prisms in her rehabilitation session. She showed good improvement in her hand-eye coordination. HIGHLIGHTS: Poor hand-eye coordination, difficulty climbing downstairs, optic ataxia, impaired field awareness, and triggering spontaneous exploration in children with perceptual visual problems can be effectively tackled by the simple incorporation of yoked prisms. VIDEO LINK: https://youtu.be/BW3cwiGDTLY.

Visual impairment in children with multiple disabilities in schools for children with special needs in South India.

Purpose: To understand/assess ocular and functional vision impairment in children with multiple disabilities with a functional vision assessment battery in addition to standard ophthalmic examinations in an outreach setting. Methods: Seven schools for children with special needs, 243 children in total, were screened for ocular disorders and functional vision impairment through school camps. Results: Among them, 37% had refractive errors needing spectacle correction. With standard ocular testing methods, the visual impairment was around 32%, but when functional vision was assessed, the functional vision impairment amounted to 70% in these children. The presence of functional vision impairment was found to be independent of the associated disability. Assessment of visual capacities such as visual closure, saccade pursuits, optic ataxia, and developmental milestones early on can help in suspecting the presence of CVI. Conclusion: Children with multiple disabilities are more at risk of functional vision impairment, which significantly impairs their ability to function in daily life. A complete functional vision assessment becomes essential to plan early intervention for these children. The significant proportion of vision impairment and functional vision loss in our study indicates the need for coordinated structured programs to address vision-related problems in children with multiple disabilities.

Clinical exome sequencing facilitates the understanding of genetic heterogeneity in Leber congenital amaurosis patients with variable phenotype in southern India.

BACKGROUND: Leber congenital amaurosis (LCA), primarily characterized by retinal degeneration is the most severe form of inherited retinal dystrophy (IRD) responsible for congenital blindness. The presence of phenotypic heterogeneity makes the diagnosis of LCA challenging, especially in the absence of pronounced disease pathognomonic, yet it can be well comprehended by employing molecular diagnosis. Therefore, the present study aimed to reveal the causative mutations in ten LCA patients with variable phenotypes using clinical exome sequencing (CES). METHODS: CES was performed in ten unrelated LCA patients. Ophthalmic information and family history of all patients were obtained to make a meaningful interpretation. The clinical exome data was analyzed and prioritized using a bioinformatics pipeline to identify mutations, which was further validated by Sanger sequencing. Segregation analysis was also performed on available family members. RESULTS: CES led to the identification of causative mutations in nine LCA patients. Seven patients harbored a mutation in six LCA candidate genes, including RPE65, LCA5 (n = 2), CRX, PRPH2, CEP290, and ALMS1, while two patients possess a mutation in IFT80 and RP1, known to cause other diseases. Three novel mutations in LCA5 (c.1823del), CRX (c.848del) and CEP290 (c.2483G > T) were identified. The current study reports for the first time, a mutation in PRPH2, CEP290, and ALMS1 from the Indian population. Additionally, we observed a novel association of LCA phenotype with IFT80 known to cause Jeune syndrome. Based on the genetic finding, the patient AS09, who harbored a mutation in the RP1 gene, was re-diagnosed with early-onset retinitis pigmentosa. CONCLUSION: In conclusion, the results underline the importance of CES in clinically diagnosed LCA patients with variable phenotypes. The correlation between mutations in candidate genes and clinical phenotypes, helps to refine the clinical diagnosis. However, molecular evaluation with a larger cohort of LCA patients is needed for better understanding of the mutational spectrum in southern India.

Intratrochlear steroid injections in acquired Brown syndrome-a case series.

PURPOSE: To present our experience in the treatment of children with acquired Brown syndrome by means of intratrochlear injection of betamethasone. METHODS: The medical records of patients treated with intratrochlear betamethasone in 2016 at the Aravind Eye Hospital, Madurai, were reviewed retrospectively. The following data were collected: pre- and postoperative orthoptic work-up, blood work, and neuroimaging. Betamethasone injection was administered 2-8 weeks following onset of symptoms. RESULTS: Five children (4 girls), 1.5-15 years of age, were included. During the postoperative period, abnormal head posture and elevation in adduction improved in 4 subjects but did not resolve completely. The median vertical deviation was 11.5Δ preoperatively and reduced to 3.5Δ postoperatively. A significant reduction in deviation was demonstrable on diplopia and Hess charting in 2 of the older children. Subject 2, who did not show improvement after injection, was prescribed prism glasses and became diplopia free. CONCLUSIONS: In this case series, children with acquired Brown syndrome of idiopathic or presumed inflammatory etiology showed significant reduction in deviation and symptoms following intratrochlear injection of betamethasone. We recommend that this treatment be considered for children affected by acquired Brown syndrome, especially those in the amblyogenic age group.

Functional and cognitive vision assessment in children with autism spectrum disorder.

PURPOSE: To assess functional vision in children with autism spectrum disorder (ASD) with a cognitive visual function battery in addition to standard ophthalmic examinations. METHODS: Subjects were recruited from a school for children with ASD. In addition to a comprehensive ophthalmic examination, all children underwent cognitive vision assessment at a tertiary ophthalmological care center in India. RESULTS: A total of 30 children were included. The distribution of the number of children with mild to moderate versus severe ASD was nearly equal based on CARS autism scores. The majority of subjects had normal color vision (16/18), contrast (24), shape discrimination (26), and perception of directionality (28). Most were not able to identify optical illusions or differentiate tests of emotions. Ocular pursuits, saccades, and recognition of size differences were often abnormal. Poor visual closure was noted in (11) subjects. The duration of fixation to Heidi face target was inversely proportional to the severity of ASD. The study further established that cognitive visual impairment was present in children with ASD irrespective of their severity of ASD. CONCLUSIONS: All subjects had some form of cognitive visual impairment independent of ASD severity.

A new surgical "noose" technique for excision of pediatric ocular adnexal and anterior orbital cysts.

We describe a "noose technique" that facilitates complete surgical excision of all forms of pediatric adnexal and anterior orbital extraocular cysts, including conjunctival retention cysts, parasitic cysts involving the conjunctiva, Tenon's capsule, or rectus muscle, superficial cysts, and deep dermoid cysts. The technique provides good exposure and facilitates handling of tissues, maintains surgical planes, minimizes bleeding, decreases injury to collateral tissues, reduces surgical time, allows for utilization of less skilled assistants, and ensures complete excision in most cases. The noose technique is a versatile procedure that can be applied to extraocular cysts of any location or size both in children and adults. We demonstrate the technique in 3 different pediatric extraocular cysts.

Mutational screening of LCA genes emphasizing RPE65 in South Indian cohort of patients.

BACKGROUND: Leber congenital amaurosis (LCA) is the most severe form of inherited retinal visual impairment in children. So far, mutations in more than 20 genes have been known to cause LCA and among them, RPE65 is a suitable candidate for gene therapy. The mutational screenings of RPE65 and other LCA genes are requisite in support of emerging gene specific therapy for LCA. Therefore, we have carried out a comprehensive LCA genes screening using a combined approach of direct sequencing and DNA microarray based Asper chip analysis. METHODOLOGY/PRINCIPAL FINDINGS: Thirty clinically diagnosed index LCA cases from Southern India were screened for coding and flanking intronic regions of RPE65 through direct sequencing. Among thirty, 25 cases excluded from RPE65 mutations were subjected to Asper chip analysis, testing 784 known pathogenic variations in 15 major LCA genes. In RPE65 screening, four different pathogenic variations including two novel (c.361insT & c.939T>A) and two known (c.394G>A & c.361delT) mutations were identified in five index cases. In the chip analysis, seven known pathogenic mutations were identified in six index cases, involving genes GUCY2D, RPGRIP1, AIPL1, CRX and IQCB1. Overall, 11 out of 30 LCA cases (36.6%) revealed pathogenic variations with the involvement of RPE65 (16.6%), GUCY2D (10%), RPGRIP1 (3.3%), AIPL1 (3.3%) and CRX & IQCB1 (3.3%). CONCLUSIONS/SIGNIFICANCE: Our study suggests that such combined screening approach is productive and cost-effective for mutation detection and can be applied in Indian LCA cohort for molecular diagnosis and genetic counselling.

Analysis of the SALL4 gene in patients with Duane retraction syndrome in a South Indian population.

Duane retraction syndrome (DRS) is a congenital eye movement disorder characterized most typically by partial or complete failure of abduction and narrowing of palpebral fissure with globe retraction on adduction. Recently mutations of the SALL4 gene on chromosome 20 have been linked to DRS associated with radial forearm malformations (Okihiro syndrome). In this prospective, non-interventional study we screened for SALL4 mutations in 72 patients clinically diagnosed as having isolated DRS or DRS associated syndromes. All four exonic and the neighboring intronic regions of SALL4 gene were amplified by sixteen sets of primers using polymerase chain reaction and were subjected to bi-directional sequencing and BLAST analysis. No genetic variations were detected in the coding region and in the neighboring intronic regions of the SALL4 gene suggesting an alternative mechanism in the pathogenesis of these disorders in the South Indian population.

Spectrum of candidate gene mutations associated with Indian familial oculocutaneous and ocular albinism.

PURPOSE: Albinism is a group of genetic disorders, showing a broad spectrum of different phenotypes. The purpose of this study was to screen known candidate genes for oculocutaneous albinism (OCA) and ocular albinism (OA) mutations in Indian patients. METHODS: Blood samples were collected from 23 probands and 13 affected family members from 23 genetically unrelated Indian families (22 diagnosed as OCA and 1 diagnosed as OA) and analyzed by bidirectional DNA sequencing of the classic OCA genes--tyrosinase (TYR, or oculocutaneous albinism IA), pink eyed dilution (P; or oculocutaneous albinism II (OCA2]), tyrosinase-related protein 1 (TYRP1), solute carrier family 45, member 2 (SLC45A2; or membrane-associated transporter protein [MATP])--and the OA1 gene, G protein-coupled receptor 143 (GPR143). RESULTS: Three missense mutations, c. 715 C>T (R239W), c. 896 G>A (R299H), c.1255 G>A (G419R), and one termination c. 832 C>T (R278X), were identified in TYR, as well as one novel mutation, c.1453 G>A (G485R) in P. One novel single nucleotide polymorphism (SNP) was identified in both TYR and P; few reported SNPs were identified. The G>A base substitution caused relatively conservative amino acid changes, which altered glycine to arginine residues within the topological domain. The novel OCA2 mutation was not present in 100 control samples. This study identified two probands carrying mutations alone, 16 probands carrying SNPs alone, 4 probands carrying both mutations and SNPs and only one proband carrying neither mutations nor SNPs. CONCLUSIONS: Although sequence analysis was performed with all five candidate genes, only four (17.39%) of the 23 probands showed mutations in TYR and 2 probands (8.69%) showed an unreported novel mutation in P. Genetic counseling for phenotypical diagnosis and genetic mutation screening of these genes will help to minimize the incidence of OCA and OA in future generations.

Autosomal recessive juvenile onset cataract associated with mutation in BFSP1.

A genome wide scan in a consanguineous family of Indian origin with autosomal recessive developmental cataracts was performed by two-point linkage analysis with 382 microsatellite markers. It showed linkage to markers on chromosome 20q, between D20S852 and D20S912, with a maximum lod score of 5.4 obtained with D20S860. This region encompasses the beaded filament structural protein 1 (BFSP1) gene. Direct sequencing revealed a 3343 bp deletion including exon 6 (c.736-1384_c.957-66 del) predicted to result in a shift of the open reading frame. This mutation was absent in 50 control individuals from south India. This is the first report of a mutation in the BFSP1 gene associated with human inherited cataracts. This further increases the genetic heterogeneity of inherited cataracts and provides clues as to the importance of BFSP1 in the cell biology of intermediate filaments and their role in the eye lens.