Non-vasogenic cystoid maculopathies.

Besides cystoid macular edema due to a blood-retinal barrier breakdown, another type of macular cystoid spaces referred to as non-vasogenic cystoid maculopathies (NVCM) may be detected on optical coherence tomography but not on fluorescein angiography. Various causes may disrupt retinal cell cohesion or impair retinal pigment epithelium (RPE) and Müller cell functions in the maintenance of retinal dehydration, resulting in cystoid spaces formation. Tractional causes include vitreomacular traction, epiretinal membranes and myopic foveoschisis. Surgical treatment does not always allow cystoid space resorption. In inherited retinal dystrophies, cystoid spaces may be part of the disease as in X-linked retinoschisis or enhanced S-cone syndrome, or occur occasionally as in bestrophinopathies, retinitis pigmentosa and allied diseases, congenital microphthalmia, choroideremia, gyrate atrophy and Bietti crystalline dystrophy. In macular telangiectasia type 2, cystoid spaces and cavitations do not depend on the fluid leakage from telangiectasia. Various causes affecting RPE function may result in NVCM such as chronic central serous chorioretinopathy and paraneoplastic syndromes. Non-exudative age macular degeneration may also be complicated by intraretinal cystoid spaces in the absence of fluorescein leakage. In these diseases, cystoid spaces occur in a context of retinal cell loss. Various causes of optic atrophy, including open-angle glaucoma, result in microcystoid spaces in the inner nuclear layer due to a retrograde transsynaptic degeneration. Lastly, drug toxicity may also induce cystoid maculopathy. Identifying NVCM on multimodal imaging, including fluorescein angiography if needed, allows guiding the diagnosis of the causative disease and choosing adequate treatment when available.

Partial recovery of visual function in a blind patient after optogenetic therapy.

Optogenetics may enable mutation-independent, circuit-specific restoration of neuronal function in neurological diseases. Retinitis pigmentosa is a neurodegenerative eye disease where loss of photoreceptors can lead to complete blindness. In a blind patient, we combined intraocular injection of an adeno-associated viral vector encoding ChrimsonR with light stimulation via engineered goggles. The goggles detect local changes in light intensity and project corresponding light pulses onto the retina in real time to activate optogenetically transduced retinal ganglion cells. The patient perceived, located, counted and touched different objects using the vector-treated eye alone while wearing the goggles. During visual perception, multichannel electroencephalographic recordings revealed object-related activity above the visual cortex. The patient could not visually detect any objects before injection with or without the goggles or after injection without the goggles. This is the first reported case of partial functional recovery in a neurodegenerative disease after optogenetic therapy.

MERTK mutation update in inherited retinal diseases.

MER tyrosine kinase (MERTK) encodes a surface receptor localized at the apical membrane of the retinal pigment epithelium. It plays a critical role in photoreceptor outer segment internalization prior to phagocytosis. Mutations in MERTK have been associated with severe autosomal recessive retinal dystrophies in the RCS rat and in humans. We present here a comprehensive review of all reported MERTK disease causing variants with the associated phenotype. In addition, we provide further data and insights of a large cohort of 1,195 inherited retinal dystrophies (IRD) index cases applying state-of-the-art genotyping techniques and summarize current knowledge. A total of 79 variants have now been identified underlying rod-cone dystrophy and cone-rod dystrophy including 11 novel variants reported here. The mutation spectrum in MERTK includes 33 missense, 12 nonsense, 12 splice defects, 12 small deletions, two small insertion-deletions, three small duplications, and two exonic and three gross deletions. Altogether, mutations in MERTK account for ∼2% of IRD cases with a severe retinal phenotype. These data are important for current and future therapeutic trials including gene replacement therapy or cell-based therapy.

Size and vitreomacular attachment of primary full-thickness macular holes.

PURPOSE: To study the relationship between the size of primary full-thickness macular hole (MH) and the vitreomacular attachment status. DESIGN: Single-centre retrospective observational case series. METHODS: The records of 100 consecutive eyes operated for primary full-thickness MH were retrospectively reviewed. The vitreous status and MH diameter were assessed on the preoperative optical coherence tomography scans. MH were classified depending on the presence or absence of vitreomacular traction (VMT) and their size as small (<250 µm), medium (250-400 µm) and large (>400 µm), as suggested in the International VMT Study Group Classification. RESULTS: 22% of MH had VMT and 13% had both VMT and a diameter <400 µm. The MH diameter was not significantly different depending on the presence or absence of VMT (respectively, 339±134 and 423±191 µm (p=0.094)), with large overlap between groups. Small, medium and large MH were similarly distributed regardless of the presence or absence of VMT (p=0.69). CONCLUSIONS: Our series of 100 MH did not reveal any significant relationship between the MH size and the presence or absence of VMT. Only 13% of MH had VMT and a diameter <400 mm, then were eligible for intravitreal ocriplasmin as a possible treatment.

Intravitreal dexamethasone implant (Ozurdex) for macular edema secondary to retinitis pigmentosa.

BACKGROUND: To evaluate the anatomical and functional outcomes of intravitreal dexamethasone implant in patients with macular edema (ME) secondary to retinitis pigmentosa (RP). METHODS: Three patients (four eyes), aged 24 to 46 years, presented with refractory ME secondary to RP. Intravitreal dexamethasone implant (Ozurdex) was administered to treat ME. The anatomical (central macular thickness [CMT]) and functional (best-corrected visual acuity [BCVA]) outcomes as well as adverse events were recorded. RESULTS: All patients completed 6 months follow-up. After intravitreal Ozurdex all patients showed regression of ME. At baseline, mean CMT was 443 ± 185 µm (range 213-619 µm); ME improved to 234 ± 68 µm (range 142-307 µm) at 1 month, to 332 ± 177 µm (range 139-513 µm) at 3 months, and to 305 ± 124 µm (range 144-447 µm) at 6 months. Recurrent ME was recorded in 2 patients (both patients at 3 months from intravitreal dexamethasone implant). Retreatment with intravitreal Ozurdex was performed in two patients. Mean BCVA improved form 20/160 (range 20/50-20/200) (baseline) to 20/100 (range 20/40-20/125) at 1 month, to ∼20/125 (range 20/100-20/200) at 3 months, and to ∼ 20/125 (range 20/100-20/160) at 6 months. No serious ocular and systemic adverse events were observed during the study period. CONCLUSIONS: Intravitreal dexamethasone implant provides anatomic and functional improvements and may represent a valuable treatment option for patients with ME secondary to RP.