MULTIMODAL EVIDENCE OF TYPE 3 NEOVASCULARIZATION IN ENHANCED S-CONE SYNDROME

PURPOSE

To investigate, using multimodal imaging, the anatomy of neovascularization in eyes with enhanced S-cone syndrome.

METHODS

Three eyes with neovascularization, from two patients with enhanced S-cone syndrome, were analyzed using fluorescein angiography, indocyanine-green and optical coherence tomography angiography imaging.

RESULTS

The eyes reported had a demonstrable Type 3 neovascularization with evidence of retinal-retinal anastomoses on fluorescein angiography, indocyanine-green and optical coherence tomography angiography imaging. One eye that was initially without neovascularization, but with chronic macular edema developed a macular hemorrhage. This eye was treated with 8 injections of intravitreal bevacizumab over 29-months resulting in a final fibrovascular lesion. The characteristics of this final lesion share similarities to the two other eyes described. In all eyes and all exams, retinal vessels are observed to communicate with the subretinal fibrovascular lesion.

CONCLUSION

We provide evidence of retinal arteriovenous anastomosis of the superficial retinal plexus to a subretinal neovascular complex in patients with enhanced S-cone syndrome and point to similarities with Type 3 neovascularization in macular telengiectasia Type 2 (MacTel2) and age-related macular degeneration. These findings provide insights into the anatomy of neovascularization in these pathologies and may lead to hypotheses of their etiologies.

ENHANCED S-CONE SYNDROME: VISUAL FUNCTION, CROSS-SECTIONAL IMAGING, AND CELLULAR STRUCTURE WITH ADAPTIVE OPTICS OPHTHALMOSCOPY

PURPOSE

To describe in detail the phenotype of a patient with enhanced S-cone syndrome.

METHODS

We describe a 13-year-old boy who presented with blurred vision, vitreous cells, cystoid macular edema refractory to steroid treatment, and a negative uveitic workup. The patient underwent a complete ophthalmic examination, full-field electroretinograms (ffERG), automatic static perimetry and multimodal imaging with spectral domain optical coherence tomography, and adaptive optics scanning laser ophthalmoscopy (AOSLO).

RESULTS

Spectral domain optical coherence tomography demonstrated cystoid macular edema and a hyperthick, delaminated midperipheral retina. Fluorescein angiography did not demonstrate macular leakage. Rod-mediated ffERGs were undetectable, and there was a supernormal response to short-wavelength stimuli compared with photopically matched longer wavelengths of light consistent with enhanced S-cone syndrome. Gene screening was positive for compound heterozygous mutations NR2E3: a known (c.119-2 A>C) and a novel (c.119-1G>A) mutation. By perimetry, sensitivities were normal or above normal for short-wavelength stimuli; there was no detectable rod-mediated vision. AOSLO demonstrated higher than normal cone densities in the perifoveal retina and evidence for smaller outer segment cone diameters.

CONCLUSION

Evidence for supernumerary cones (at least twice the normal complement) by AOSLO and spectral domain optical coherence tomography was associated with supernormal S-cone sensitivities and electroretinogram responses confirming previous in vivo findings in postmortem human specimens. Smaller than normal cones in enhanced S-cone syndrome may represent "hybrid" photoreceptors analogous to the rd7/rd7 murine model of the disease.

Optical Coherence Tomography Neuro-Toolbox for the Diagnosis and Management of Papilledema, Optic Disc Edema, and Pseudopapilledema

BACKGROUND

Distinguishing optic disc edema from pseudopapilledema is a common, sometimes challenging clinical problem. Advances in spectral-domain optical coherence tomography (SD-OCT) of the optic nerve head (ONH) has proven to be a cost effective, noninvasive, outpatient procedure that may help. At its core are tools that quantify the thickness of the retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL). The SD-OCT also provides a set of tools that may be qualitatively interpreted in the same way that we read an MRI. They include the transverse axial, en face, and circular tomogram. Our goal is to describe a practical office-based set of tools using SD-OCT in the diagnosis and monitoring of papilledema, optic disc edema, and pseudopapilledema.

EVIDENCE ACQUISITION

Searches on PubMed were performed using combinations of the following key words: OCT, papilledema, pseudopapilledema, optic disc drusen, retinal folds (RF), and choroidal folds (CF).

RESULTS

The principal elements of SD-OCT analysis of the ONH are the RNFL and GC-IPL thickness; however, these metrics have limitations when swelling is severe. Qualitative interpretation of the transverse axial SD-OCT aids in assessing peripapillary shape that may help distinguish papilledema from pseudopapilledema, evaluate atypical optic neuropathies, diagnose shunt failures, and identify outer RF and CF. There is a consensus that the SD-OCT is the most sensitive way of identifying buried optic disc drusen. En face SD-OCT is especially effective at detecting peripapillary wrinkles and outer retinal creases, both of which are common and distinctive signs of optic disc edema that rule out pseudopapilledema. Mechanically stressing the ONH in the adducted eye position, in patients with papilledema, may expose folds and peripapillary deformations that may not be evident in primary position. We also discuss how to optimize the acquisition and registration of SD-OCT images.

CONCLUSIONS

The SD-OCT is not a substitute for a complete history and a careful examination. It is, however, a convenient ancillary test that aids in the diagnosis and management of papilledema, optic disc edema, and pseudopapilledema. It is particularly helpful in monitoring changes over the course of time and distinguishing low-grade papilledema from buried drusen. The application of the SD-OCT toolbox depends on optimizing the acquisition of images, understanding its limitations, recognizing common artifacts, and accurately interpreting images in the context of both history and clinical findings.

Optic Atrophy and Inner Retinal Thinning in CACNA1F-related Congenital Stationary Night Blindness

Hemizygous pathogenic variants in CACNA1F lead to defective signal transmission from retinal photoreceptors to bipolar cells and cause incomplete congenital stationary night blindness in humans. Although the primary defect is at the terminal end of first-order neurons (photoreceptors), there is limited knowledge of higher-order neuronal changes (inner retinal) in this disorder. This study aimed to investigate inner retinal changes in CACNA1F-retinopathy by analyzing macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness and optic disc pallor in 22 subjects with molecularly confirmed CACNA1F-retinopathy. Detailed ocular phenotypic data including distance and color vision, refraction and electroretinogram (ERG) were collected. Distance vision was universally reduced (mean: 0.42 LogMAR), six had abnormal color vision and myopia was common (n = 15; mean: −6.32 diopters). Mean GCL-IPL thickness was significantly lower in patients (55.00 µm) compared to age-matched controls (n = 87; 84.57 µm; p << 0.001). The GCL-IPL thickness correlated with scotopic standard (p = 0.04) and bright-flash (p = 0.014) ERG b/a ratios and photopic b-wave amplitudes (p = 0.05). Twenty-one patients had some degree of disc pallor (bilateral in 19). Fifteen putative disease-causing, including five novel variants were identified. This study establishes macular inner retinal thinning and optic atrophy as characteristic features of CACNA1F-retinopathy, which are independent of myopia and could impact potential future treatment strategies.

Novel Pathogenic Sequence Variants in NR2E3 and Clinical Findings in Three Patients

A retrospective review of the clinical records of patients seen at the Oxford Eye Hospital identified as having NR2E3 mutations was performed. The data included symptoms, best-corrected visual acuity, multimodal retinal imaging, visual fields and electrophysiology testing. Three participants were identified with biallelic NR2E3 pathogenic sequence variants detected using a targeted NGS gene panel, two of which were novel. Participant I was a Nepalese male aged 68 years, and participants II and III were white Caucasian females aged 69 and 10 years old, respectively. All three had childhood onset nyctalopia, a progressive decrease in central vision, and visual field loss. Patients I and III had photopsia, patient II had photosensitivity and patient III also had photophobia. Visual acuities in patients I and II were preserved even into the seventh decade, with the worst visual acuity measured at 6/36. Visual field constriction was severe in participant I, less so in II, and fields were full to bright targets targets in participant III. Electrophysiology testing in all three demonstrated loss of rod function. The three patients share some of the typical distinctive features of NR2E3 retinopathies, as well as a novel clinical observation of foveal ellipsoid thickening.

Cellular imaging of inherited retinal diseases using adaptive optics

Adaptive optics (AO) is an insightful tool that has been increasingly applied to existing imaging systems for viewing the retina at a cellular level. By correcting for individual optical aberrations, AO offers an improvement in transverse resolution from 10-15 μm to ~2 μm, enabling assessment of individual retinal cell types. One of the settings in which its utility has been recognised is that of the inherited retinal diseases (IRDs), the genetic and clinical heterogeneity of which warrants better cellular characterisation. In this review, we provide a summary of the basic principles of AO, its integration into multiple retinal imaging modalities and its clinical applications, focusing primarily on IRDs. Furthermore, we present a comprehensive summary of AO-based cellular findings in IRDs according to their associated disease-causing genes.

Novel Missense Mutations in BEST1 Are Associated with Bestrophinopathies in Lebanese Patients

To identify Bestrophin 1 (BEST1) causative mutations in six Lebanese patients from three families, of whom four had a presumed clinical diagnosis of autosomal recessive bestrophinopathy (ARB) and two showed a phenotype with a single vitelliform lesion, patients were subjected to standard ophthalmic examinations. In addition, BEST1 exons and their flanking regions were amplified and sequenced by Sanger sequencing. Co-segregation and detailed bio-informatic analyses were performed. Clinical examination results were consistent with ARB diagnosis for all index patients showing multifocal vitelliform lesions and a markedly reduced light peak in the electrooculogram, including the two patients with a single vitelliform lesion. In all cases, most likely disease-causing BEST1 mutations co-segregated with the phenotype. The ARB cases showed homozygous missense variants (M1, c.209A>G, p.(Asp70Gly) in exon 3, M2, c.1403C>T; p.(Pro468Leu) in exon 10 and M3, c.830C>T, p.(Thr277Met) in exon 7), while the two patients with a single vitelliform lesion were compound heterozygous for M1 and M2. To our knowledge, this is the first study describing mutations in Lebanese patients with bestrophinopathy, where novel biallelic BEST1 mutations associated with two phenotypes were identified. Homozygous mutations were associated with multifocal lesions, subretinal fluid, and intraretinal cysts, whereas compound heterozygous ones were responsible for a single macular vitelliform lesion.

Familial Exudative Vitreoretinopathy Imaged With Optical Coherence Tomography Angiography

The authors present a case of a 29-year-old man who presented to the Department of Ophthalmology at their institution to complete a peripheral laser treatment in his left eye for familial exudative vitreoretinopathy complicated by tractional macular edema. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e112-e113.].

[Analysis on the clinical and retinal imaging characteristics of autosomal recessive bestrophinopathy]

Objective: To study the clinical and imaging features of autosomal recessive bestrophinopathy (ARB). Methods: Retrospective study. The clinical and imaging data of 14 participants were analyzed in using autofluorescence (AF), fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT). Ten patients were screened for mutations in BEST1 gene. Results: Retinopathy of ARB were shown as bilaterally and circularly distributed yellow subretinal deposits in the mid-peripheral and posterior retina, which was observed more clearly by AF and FA. The abnormalities were observed as hyperreflection between the sub-retinal pigment epithelium space as well as the subretinal space by SD-OCT imaging. All of the patients showed serous retinal detachment, and 4 of them were found to have intraretinal schisis. Other ocular complications include choroidal neovascularization (CNV) and angle closure glaucoma (ACG) were also found in the patients. Genetic examinations showed that the mutations are compound heterozygous in five patients, homozygous in one patient and heterozygous in only one of the rest 4 patients. Conclusions: The combination of clinical and retinal imaging data may facilitate the diagnosis of ARB. Physicians should be cautious of the vision-threatening complications of the disease. (Chin J Ophthalmol, 2018, 54: 263-269).

Two novel mutations in XYLT2 cause spondyloocular syndrome

We report on two new patients with spondyloocular syndrome. Both patients harbor novel homozygous mutations in the XYLT2 gene. The patients present severe generalized osteoporosis, multiple fractures, short stature, cataract, and mild hearing impairment. XYLT2 mutations have been identified in spondyloocular syndrome, however only five mutations have been reported previously. These two patients with novel mutations extend the phenotypic and genotypic spectrum of spondyloocular syndrome.

[Guidance of Medical Care for Familial Exudative Vitreoretinopathy：Research on Rare and Intractable Diseases, Health and Labour Sciences Research Grants]

Familial exudative vitreoretinopathy is a hereditary insufficiency of retinal vascularture, which manifests a variety of vitreoretinal abnormalities, including nonvascularlized retina, abnormality of retinal vessel growing, dragged retina, retinal folds and total retinal detachment. While causative genes have been identified, cases are often sporadic. Periodic examination is necessary to find recurrence of the disease and late complications, including rhegmatogenous retinal detachment, cataract and glaucoma.

Amblyopia secondary to iris cyst

CLINICAL CASE

A 5 year-old child diagnosed with moderate anisometropic amblyopia secondary to primary cyst of iris pigment epithelium. He was evaluated with ultrasound biomicroscopy (BMU) and optical coherence tomography (OCT) of anterior segment.

DISCUSSION

The OCT, although with some limitations, is a useful tool to study the anterior segment. It is probably more recommendable than BMU in the childhood.

The efficacy of optic nerve ultrasonography for differentiating papilloedema from pseudopapilloedema in eyes with swollen optic discs

PURPOSE

To evaluate the diagnostic yield of optic nerve ultrasonography (US) in distinguishing between papilloedema (swollen discs owing to raised intracranial pressure) and pseudopapilloedema.

METHODS

We prospectively evaluated all patients with bilateral optic disc swelling who underwent a complete neuro-ophthalmological examination. Suitable patients were referred for neuroimaging (computerized tomography or magnetic resonance imaging) and lumbar puncture. They underwent optic nerve US (A-mode and B-mode), and the findings were compared with the final clinical assessment. Sensitivity, specificity and predictive values for US distinction between true papilloedema and pseudopapilloedema were calculated and compared with those of the other imaging tests.

RESULTS

Forty-four patients were enrolled. Ultrasonography detected papilloedema with a high degree of sensitivity (85%) when the normal optic nerve width (ONW) was set at ≤3.3 mm, and with an even higher degree of sensitivity (95%) when the normal ONW was set at ≤3.0 mm. Ultrasonography had a high negative predictive value for detecting papilloedema: 83% when the normal ONW was set at ≤3.3 mm and 93% when it was set at ≤3.0 mm. There was a significant correlation between the US findings and the final diagnosis (p < 0.001) when the upper limit of the normal ONW was set at 3.0 mm.

CONCLUSIONS

Ultrasonography findings of the ONW correlated well with the final diagnosis of papilloedema or pseudopapilloedema, especially when the upper limit of the normal ONW was set at 3.0 mm. Ultrasonography could be a useful non-invasive technique for differentiating papilloedema from other causes for swollen discs, such as pseudopapilloedema.

[Applications of noninvasive high-resolution ultrasound imaging in ophthalmology]

While ultrasonography has been applied to eye examination since the beginning of medical applications of ultrasound, the use of high frequencies is relatively recent in this context. Recent developments since the 1990s have made devices available that are well suited for examining the anterior segment as well as the posterior pole, providing precise data for corneal lesions, iris, chamber angle, and ciliary body abnormalities, and lesions of the papilla and macula.

Heritable unilateral clinical anophthalmia

We examined a newborn child with unilateral right-sided clinical anophthalmos born to a mother with unilateral left-sided anophthalmos. Although rare, isolated nonsyndromic heritable unilateral anophthalmia and microphthalmia have been reported in the literature. We briefly review the genetics of such anomalies and discuss the importance of a full clinical genetics evaluation. Treatment of this patient's anophthalmic socket consists of progressive conformer expansion to be followed by placement of a self-inflating polymer expander.

Ectopia lentis et pupillae. A hypothesis revisited

BACKGROUND

Ectopia lentis et pupillae (ELeP) is a rare congenital inherited disorder characterized by lenticular and pupillary ectopia. Recent speculation on its pathogenesis is based on clinical observation and includes a neuroectodermal defect or persistence of fetal vasculature. None of these reports included histopathology or imaging studies.

STUDY DESIGN

Case report and literature review.

INTERVENTION

The authors examined a 55-year-old woman with ELeP using 10-MHz and 50-MHz ultrasonography to demonstrate the structural abnormalities present. Five patients (eight eyes) who had undergone cataract extraction without lens implantation were also examined.

RESULTS

In the patient with ELeP, the right pupil was displaced inferiorly and the left temporally. An ultrasound scan at 10 MHz showed both lenses lying inferiorly in the vitreous. An ultrasound scan at 50 MHz allowed detailed examination of the anterior segment, including the iris and ciliary body, and showed two main features in each eye, including a lack of definition of ciliary processes, except in that quadrant toward which the pupil was displaced, and a membrane-like structure extending forward and attaching to the proximal pupil margin. The membrane passed over the tips of the ciliary processes to a more posterior origin.

CONCLUSIONS

The only histologic reports of this condition are from the beginning of this century in the German literature. Ultrasonography at 50 MHz allows high-resolution in vivo imaging of anterior structures that are not clinically visible. The authors' findings in this case of ELeP are sufficiently different from those of non-ELeP-related aphakia to suggest that they are not solely due to aphakia. Furthermore, the authors' findings are very similar to the only histologic reports suggesting that the pupillary and lenticular ectopia results from mechanical tethering of the pupil with zonular disruption. This hypothesis has not been discussed in the recent literature.