To investigate the properties and origin of retinal intrinsic signals by functional optical coherence tomography (fOCT) in macaque retinas.
We modified a spectral domain OCT system to be able to give ...short-duration flashes or continuous light stimulation to the retina of three adult macaque monkeys (Macaca mulatta) under general anesthesia. Changes in the intensities of the OCT signals following the stimulus were determined.
Stimulus-evoked decreases or increases in the OCT signals were observed in the photoreceptor inner segment ellipsoids and outer segments, respectively. Experiments with focal and colored stimuli confirmed that these fOCT signals originated from the photoreceptors. No diffuse changes in the OCT signals were detected in the inner retinal layers; however, there were slow changes in small discrete areas where the retinal vessels were located. The polarity of the fOCT signals in the inner retinal layer was dependent on each activated region, and one of the possible sources of the reflectance changes was the light-scattering changes of the retinal vessels.
The fOCT signals in the macaque retina consist of at least three components: light-scattering changes from the photoreceptor inner segment ellipsoids, light-scattering changes from the outer segments, and slow light-scattering changes from the blood vessels in the inner retina. This technique has the potential of mapping local neuronal activity three-dimensionally and may help in the diagnosis of retinal disorders of different retinal origins.
The purpose of this study was to investigate frequent disease-causing gene mutations in autosomal recessive retinitis pigmentosa (arRP) in the Japanese population.
In total, 99 Japanese patients with ...non-syndromic and unrelated arRP or sporadic RP (spRP) were recruited in this study and ophthalmic examinations were conducted for the diagnosis of RP. Among these patients, whole exome sequencing analysis of 30 RP patients and direct sequencing screening of all CNGA1 exons of the other 69 RP patients were performed.
Whole exome sequencing of 30 arRP/spRP patients identified disease-causing gene mutations of CNGA1 (four patients), EYS (three patients) and SAG (one patient) in eight patients and potential disease-causing gene variants of USH2A (two patients), EYS (one patient), TULP1 (one patient) and C2orf71 (one patient) in five patients. Screening of an additional 69 arRP/spRP patients for the CNGA1 gene mutation revealed one patient with a homozygous mutation.
This is the first identification of CNGA1 mutations in arRP Japanese patients. The frequency of CNGA1 gene mutation was 5.1% (5/99 patients). CNGA1 mutations are one of the most frequent arRP-causing mutations in Japanese patients.
Purpose
To establish with negative electroretinogram (ERG) the clinical entity of eight patients with unilateral severe photophobia, essentially normal fundus, good visual acuity, and severe cone and ...rod dysfunction.
Study design
Multicenter retrospective observation case series.
Methods
Comprehensive ophthalmologic examinations were performed, including best-corrected visual acuity (BCVA), full-field ERGs and multifocal ERGs (mfERGs), fundus photographs, and OCT. Systemic and genetic examinations were performed.
Results
The mean (± SD) age at the onset was 60.0 ± 8.4 years, and the six patients noticed severe photophobia in the affected eye in spite of almost normal fundus appearance and good BCVA. The dark-adapted bright flash ERGs in the affected eye had relatively well-preserved a-waves and depressed b-waves, i.e., a negative ERG. Cone ERGs and both b- and d-waves of the photopic long-duration ERGs were almost undetectable. Rod ERGs were severely reduced; however, only two patients complained of night blindness. In five patients, the mfERGs were extinguished in the periphery but preserved in the central retina, resulting in good BCVA. Electrophysiological findings indicated a severe diffuse dysfunction of the inner retina affecting bipolar cells of both ON- and OFF-pathways, and in five patients there was a reduction in the thickness of the inner nuclear layer. In seven patients the retinal arteries were attenuated. Anti-retinal antibodies were detected in the serum of two patients. No genetic causes were found.
Conclusions
The common features in the eight patients with unilateral negative ERGs suggest a new disease entity of unilateral acute inner retinal layer dysfunction. In most patients, the only subjective complain was photophobia.
Occult macular dystrophy (OMD) is an inherited macular dystrophy characterized by progressive loss of macular function but normal ophthalmoscopic appearance. Typical OMD is characterized by a central ...cone dysfunction leading to a loss of vision despite normal ophthalmoscopic appearance, normal fluorescein angiography, and normal full-field electroretinogram (ERGs), but the amplitudes of the focal macular ERGs and multifocal ERGs are significantly reduced at the central retina. Linkage analysis of two OMD families was performed by the SNP High Throughput Linkage analysis system (SNP HiTLink), localizing the disease locus to chromosome 8p22-p23. Among the 128 genes in the linkage region, 22 genes were expressed in the retina, and four candidate genes were selected. No mutations were found in the first three candidate genes, methionine sulfoxide reductase A (MSRA), GATA binding 4 (GATA4), and pericentriolar material 1 (PCM1). However, amino acid substitution of p.Arg45Trp in retinitis pigmentosa 1-like 1 (RP1L1) was found in three OMD families and p.Trp960Arg in a remaining OMD family. These two mutations were detected in all affected individuals but in none of the 876 controls. Immunohistochemistry of RP1L1 in the retina section of cynomolgus monkey revealed expression in the rod and cone photoreceptor, supporting a role of RP1L1 in the photoreceptors that, when disrupted by mutation, leads to OMD. Identification of RP1L1 mutations as causative for OMD has potentially broader implications for understanding the differential cone photoreceptor functions in the fovea and the peripheral retina.
To assess the morphological changes of cone photoreceptors in eyes with autosomal recessive bestrophinopathy.
Both eyes of five patients with autosomal recessive bestrophinopathyunderwent spectral ...domain optical coherence tomography and adaptive optics fundus imaging. The cone photoreceptor densities were measured at intervals of 100 μm between 500 μm nasal and temporal eccentricities from the foveal center.
The median age of the patients was 30 years (range, 23-45 years), and the best-corrected visual acuity ranged from 20/20 to 20/80. Adaptive optics fundus images showed reduced cone photoreceptor densities corresponding to the damages of the photoreceptor layer in the spectral domain optical coherence tomography images in four patients with relatively good best-corrected visual acuity. The cone photoreceptor densities at the center of the fovea were less than one-third of the normal cone densities (range 11,600-30,400 cells/mm). Cone photoreceptor mosaics were visible over the lesions with serous retinal detachment and retinal edema, although they were partially hyporeflective.
There is a significant cone photoreceptor loss in the macular region of patients with autosomal recessive bestrophinopathy, although they had relatively good visual acuity. Monitoring cone photoreceptors by adaptive optics fundus imaging should provide accurate assessments of the disease status and indications for future therapeutic interventions.
To report the optical coherence tomography (OCT) findings in eyes with vitreomacular traction (VMT) or with an epiretinal membrane (ERM).
Retrospective case series.
Fifty-four eyes of 45 consecutive ...patients with subjective visual disturbances resulting from VMT or idiopathic ERM were studied.
The morphologic features of the photoreceptor layer at the foveal center were determined and the central foveal thickness (CFT) was measured by spectral-domain (SD) OCT.
The morphologic characteristics of the foveal region observed by SD OCT.
A roundish or diffuse highly reflective region was observed between the photoreceptor inner segment/outer segment junction line and the cone outer segment tip line at the center of the fovea. This highly reflective region was present in 7 of 7 cases of VMT and 30 of 47 cases of ERM. In the ERM cases, the mean CFT of the cases with the highly reflective region was significantly thicker than that in cases without it. The highly reflective region disappeared when the inward traction on the fovea was released surgically or spontaneously.
The highly reflective region is a characteristic sign observed in the OCT images of eyes with VMT and ERM, and it has been termed the cotton ball sign after its appearance. The presence of the cotton ball sign indicates an inward traction on the fovea and may be a predictor of visual impairment.
2p15p16.1 microdeletion syndrome is a recently recognized congenital disorder characterized by developmental delay and dysmorphic features. RP2-associated retinal disorder (RP2-RD) is an X-linked ...inherited retinal disease with a childhood onset caused by a loss-of-function variant in the RP2 gene. Here, we describe a 14-year-old boy with double diagnoses of 2p15p16.1 microdeletion syndrome and RP2-RD. The recurrence risk of each condition and the indication for potential therapeutic options for RP2-RD are discussed.
Abstract Purpose To report the clinical and genetic findings of 9 Japanese patients with autosomal recessive bestrophinopathy (ARB). Design Retrospective, multicenter observational case series. ...Methods Nine ARB patients from 7 unrelated Japanese families that were examined in 3 institutions in Japan were studied. A series of ophthalmic examinations including fundus photography, spectral domain optical coherence tomography, fundus autofluorescence, electrooculography (EOG), electroretinography, and the results of genetic analysis were reviewed. Results Genetic analyses identified 7 pathogenic variants in BEST1 including 2 novel variants, c.478G>C (p.A160P) and c.948+1delG. Homozygous variants were found in 4 families and compound heterozygous variants were found in 3 families. Two patients were diagnosed as ARB only after the whole exome sequencing analyses. The Arden ratio of the EOG was less than 1.5 in all 7 patients tested. Vitelliform lesions typical for BVMD were not seen in any of the patients. Seven patients shared some of the previously described features of ARB; subretinal deposits, extensive subretinal fluid, and cystoid macular edema (CME). However, the other two patients with severe retinal degeneration lacked these features. Focal choroidal excavations were present bilaterally in two patients. One case had a marked reduction of the CME and expansion of subretinal deposits over an 8 year of follow-up period. Conclusions Japanese ARB patients had some but not all of the previously described features. Genetic analyses are essential to diagnose ARB correctly in consequence of considerable phenotypic variations.
The human fovea is a specialized pit structure in the central retina. Foveal hypoplasia is a condition where the foveal pit does not fully develop, and it is associated with poor vision. Autosomal ...dominant isolated foveal hypoplasia (FVH1) is a rare condition of foveal hypoplasia (FH) that lacks any other ocular manifestations. FVH1 is associated with hypomorphic mutations in the
gene that encodes a sequence-specific DNA-binding transcription factor for morphogenesis and evolution of the eye. We report our findings in 17 patients with
mutations associated with FVH1 or FH with aniridia and corneal opacities. Patients with three mutations, p.V78E, p.V83F and p.R128H, in the C-terminal subdomain of the paired domain (CTS) consistently have severe FH. Luciferase assays for a single reporter containing a representative PAX6 binding site indicated that the transcriptional activities of these mutations were significantly reduced, comparable to that of the truncation mutation of p.G65Rfs*5. Patients with p.P20S in the N-terminal subdomain of the paired domain, and a patient with p.N365K in the proline-serine-threonine-rich domain (PSTD) had mild FH. A patient with p.Q255L in the homeodomain had severe FH. The P20S and Q255L mutants did not affect the transcriptional activity. Mutant N365K has a retained DNA-binding activity but a reduced transcriptional activity, due to a low PSTD transactivation. These findings demonstrated that mutations associated with FVH1 underlie a functional divergence between DNA-binding ability and transcriptional activity. We conclude that a wide range of mutations in the
gene is not limited to the CST region and are responsible for FVH1.
To quantitatively evaluate changes in the sub-retinal pigment epithelial (RPE) space and determine the association with recurrent neovascular age-related macular degeneration (AMD). Twenty-two eyes ...treated with intravitreal aflibercept for treatment-naïve neovascular AMD were studied retrospectively. The sub-RPE area, volume, and central retinal thickness (CRT) were evaluated 1 and 2 months after the loading phase using spectral-domain optical coherence tomography. Recurrence was defined as newly detected neovascular activity during the 6 months after the loading phase. In eyes with recurrent AMD, the sub-RPE area increased significantly (P = 0.036) from 1 to 2 months after the loading phase and the sub-RPE volume increased marginally (P = 0.06). Subgroup analysis showed significant (P = 0.008 and P = 0.016, respectively) increases in the sub-RPE area and volume in typical AMD. In eyes with no recurrence, no significant changes occurred in the two parameters. No significant CRT changes occurred in eyes with or without a recurrence. A quantitative analysis demonstrated an increased likelihood of the sub-RPE space shortly after the loading phase in eyes with recurrent AMD; no changes occurred in eyes without a recurrence. These early changes in the sub-RPE space could indicate disease activity and are valuable for predicting recurrences of neovascular AMD.
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