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Purpose To assess functional and anatomical outcomes of internal limiting membrane (ILM) inverted flap in highly myopic macular holes (HMMHs) with outer-retinoschisis (O-RS). Methods Retrospective interventional analysis of 19 eyes with HMMH and O-RS undergoing vitrectomy and ILM inverted flap. At baseline and every follow-up visit (1, 3, 6, 12 months and the most recent) we performed best-corrected visual acuity (BCVA, Snellen) and optical coherence tomography (OCT), collecting several parameters: minimum linear diameter (MLD), basal diameter (BD), peri-HMMH nasal and temporal retinal thickness (RT NAS and RT TEM ), peri-HMMH nasal and temporal O-RS height (O-RS NAS and O-RS TEM ). The ratios O-RS NAS / RT NAS and O-RS TEM /RT TEM were defined as %O-RS NAS and %O-RS TEM . Postoperatively, we distinguished classic HMMH closure ( n  = 14) from a newly described “delayed” closure pattern ( n  = 5). Results Primary anatomical closure was obtained in 89% of eyes. Mean BCVA improved from 0.23 ± 0.17 to 0.44 ± 0.20 and 0.46 ± 0.25 at 6-months and final follow-up ( p  = 0.009 and p  = 0.001, respectively). At every follow-up, “classic” vs. “delayed closure” did not influence BCVA (all p  > 0.05). Baseline O-RS NAS ( p  = 0.026), O-RS TEM ( p  = 0.04), %O-RS NAS ( p  = 0.04) and %O-RS TEM (0.004), were significantly associated with the “flap closure” pattern, differently from MLD and BD. In the “delayed closure” subgroup we reported a 100% closure rate, but 65.8 ± 64.4 days after first surgery. Meantime, OCT showed an inverted ILM flap covering an area of persistent tissue loss. O-RS NAS and O-RS TEM progressively reduced until HMMH closure. Conclusion Inverted flap is useful to close HMMH with O-RS. In case of “delayed closure” pattern, watchful-waiting allows for HMMH self-sealing, without impact on BCVA. Key messages What is known Inverted internal limiting membrane (ILM) flap showed favorable anatomic success in cases of highly myopic macular holes (HMMH). What is new HMMHs with outer retinoschisis (class 2c of the staging system) may close following a classic or “delayed closure” pattern. In cases of delayed closure, it took a variable range of 30–179 days to seal the HMMH but no further surgery was advisable. Post-operative BCVA improvement was not impacted at any follow-ups when comparing “delayed” and “classic” closure subgroups.

BACKGROUND AND OBJECTIVE: To provide an overview of progressive retinoschisis-related retinal detachment (RSRD) management at a tertiary referral center. MATERIALS AND METHODS: Single-institution retrospective case series from January 1, 2003, to May 1, 2020. RESULTS: Progressive RSRD occurred in 0.9% of patients with retinoschisis. Mean (range) age at time of surgery was 58.7 years (40.0 to 74.0). Ten eyes were initially treated with scleral buckle, three eyes with vitrectomy, and three eyes with combined scleral buckle and vitrectomy. Overall reattachment rate was 100.0%; single-surgery success was 56.2%. Proliferative vitreoretinopathy developed in 10.0% of scleral buckles, 33.3% of vitrectomies, and 33.3% of combined surgeries. CONCLUSIONS: Progressive RSRD is rare and poses surgical management challenges. Final retinal attachment can be achieved successfully but often requires secondary and staged surgeries. Localization of outer retinal breaks may help guide surgical management. Further research—such as a large-scale, prospective, multicenter, randomized trial—would be needed to determine the optimal surgical technique. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:132–138.]

Background X-linked juvenile retinoschisis (XLRS) is an inherited disease caused by RS1 gene mutation, which leads to retinal splitting and visual impairment. The mechanism of RS1 -associated retinal degeneration is not fully understood. Besides, animal models of XLRS have limitations in the study of XLRS. Here, we used human induced pluripotent stem cell (hiPSC)-derived retinal organoids (ROs) to investigate the disease mechanisms and potential treatments for XLRS. Methods hiPSCs reprogrammed from peripheral blood mononuclear cells of two RS1 mutant (E72K) XLRS patients were differentiated into ROs. Subsequently, we explored whether RS1 mutation could affect RO development and explore the effectiveness of RS1 gene augmentation therapy. Results ROs derived from RS1 (E72K) mutation hiPSCs exhibited a developmental delay in the photoreceptor, retinoschisin (RS1) deficiency, and altered spontaneous activity compared with control ROs. Furthermore, the delays in development were associated with decreased expression of rod-specific precursor markers (NRL) and photoreceptor-specific markers (RCVRN). Adeno-associated virus (AAV)-mediated gene augmentation with RS1 at the photoreceptor immature stage rescued the rod photoreceptor developmental delay in ROs with the RS1 (E72K) mutation. Conclusions The RS1 (E72K) mutation results in the photoreceptor development delay in ROs and can be partially rescued by the RS1 gene augmentation therapy.

ObjectiveTo evaluate the morphologic and functional outcomes of different optical coherence tomography (OCT) patterns of myopic foveoschisis after vitrectomy with Inner Limiting Membrane (ILM) peeling.MethodsIn this prospective non-randomised study, 62 consecutive eyes with Myopic Foveoschisis were categorised into three groups according to OCT pattern: retinoschisis type (Rt) Group (23/62), foveal detachment type (FDt) Group (20/62) and macular hole type (MHt) Group (19/62). All patients underwent 25-Gauge vitrectomy and ILM peeling. Air or gas tamponade was used. All patients were observed at month 1, 2, 4 and 6 after surgery. Main outcomes measures: surgical success as resolution of myopic foveoschisis, central retinal thickness (CRT), IS/OS junction recovery and best-corrected visual acuity (BCVA) measurement. Any complication was reported.ResultsIn all eyes OCT showed a resolution of the retinoschisis, foveal detachment and macular hole pattern, respectively. CRT significantly decreased in all Groups (p < .001), mainly in MHt. IS/OS junction recovery was mainly observed in MHt. BCVA significantly increased in all Groups (p < .01). A functional gain ≥2 Snellen lines occurred in 70, 85 and 68% in the Rt, FDt and MHt Group, respectively. Final BCVA was correlated with preoperative BCVA (R 0.74, p < 0.0001), postoperative CRT (R −0.49, p < 0.0001), and the recovery of IS/OS junction at 6 months (R 0.76, p < 0.0001). Few postoperative complications occurred.ConclusionsVitrectomy with ILM peeling results in favourable anatomic and functional outcomes for different patterns of myopic foveoschisis.

X-linked juvenile retinoschisis (XLRS) is an early-onset progressive inherited retinopathy affecting males. It is characterized by abnormalities in the macula, with formation of cystoid retinal cavities, frequently accompanied by splitting of the retinal layers, impaired synaptic transmission of visual signals, and associated loss of visual acuity. XLRS is caused by loss-of-function mutations in the retinoschisin gene located on the X chromosome (RS1, MIM 30083). While proof-of-concept studies for gene augmentation therapy have been promising in in vitro and rodent models, clinical trials in XLRS patients have not been successful thus far. We performed a systematic literature investigation using search strings related to XLRS and gene therapy in in vivo and in vitro models. Three rounds of screening (title/abstract, full text and qualitative) were performed by two independent reviewers until consensus was reached. Characteristics related to study design and intervention were extracted from all studies. Results were divided into studies using (1) viral and (2) non-viral therapies. All in vivo rodent studies that used viral vectors were assessed for quality and risk of bias using the SYRCLE’s risk-of-bias tool. Studies using alternative and non-viral delivery techniques, either in vivo or in vitro, were extracted and reviewed qualitatively, given the diverse and dispersed nature of the information. For in-depth analysis of in vivo studies using viral vectors, outcome data for optical coherence tomography (OCT), immunohistopathology and electroretinography (ERG) were extracted. Meta-analyses were performed on the effect of recombinant adeno-associated viral vector (AAV)-mediated gene augmentation therapies on a- and b-wave amplitude as well as the ratio between b- and a-wave amplitudes (b/a-ratio) extracted from ERG data. Subgroup analyses and meta-regression were performed for model, dose, age at injection, follow-up time point and delivery method. Between-study heterogeneity was assessed with a Chi-square test of homogeneity (I2). We identified 25 studies that target RS1 and met our search string. A total of 19 of these studies reported rodent viral methods in vivo. Six of the 25 studies used non-viral or alternative delivery methods, either in vitro or in vivo. Of these, five studies described non-viral methods and one study described an alternative delivery method. The 19 aforementioned in vivo studies were assessed for risk of bias and quality assessments and showed inconsistency in reporting. This resulted in an unclear risk of bias in most included studies. All 19 studies used AAVs to deliver intact human or murine RS1 in rodent models for XLRS. Meta-analyses of a-wave amplitude, b-wave amplitude, and b/a-ratio showed that, overall, AAV-mediated gene augmentation therapy significantly ameliorated the disease phenotype on these parameters. Subgroup analyses and meta-regression showed significant correlations between b-wave amplitude effect size and dose, although between-study heterogeneity was high. This systematic review reiterates the high potential for gene therapy in XLRS, while highlighting the importance of careful preclinical study design and reporting. The establishment of a systematic approach in these studies is essential to effectively translate this knowledge into novel and improved treatment alternatives.

Background/Objective: The Rs1 exon-1-del rat (Rs1KO) XLRS model shows normal retinal development until postnatal day 12 (P12) when small cystic spaces start to form in the inner nuclear layer. These enlarge rapidly, peak at P15, and then collapse by P19. These events overlap with eye opening at P12–P15. We investigated whether new light-driven retinal activity could contribute to the appearance and progression of schisis cavities in this rat model of XLRS disease. Methods: For dark rearing (D/D), mating pairs of Rs1KO strain were raised in total darkness in a special vivarium at UC Davis. When pups were born, they were maintained in total darkness, and eyes were collected at P12, P15, and P30 (n = 3/group) for each of the D/D and cyclic light-reared 12 h light–12 h dark (L/D) Rs1KO and wild-type (WT) littermates. Eyes were fixed, paraffin-embedded, and sectioned. Tissue morphology was examined by H&E and marker expression of retinoschisin1 (Rs1), rhodopsin (Rho), and postsynaptic protein 95 (Psd95) by fluorescent immunohistochemistry. H&E-stained images were analyzed with ImageJ version 1.54h to quantify cavity size using the “Analyze Particles” function. Results: Small intra-retinal schisis cavities begin to form by P12 in the inner retina of both D/D and L/D animals. Cavity formation was equivalent or more pronounced in D/D animals than in L/D animals. We compared Iba1 (activation marker of immune cells) distribution and found that by P12, when schisis appeared, Iba1+ cells had accumulated in regions of schisis. Iba1+ cells were more abundant in Rs1KO animals than WT animals and appeared slightly more prevalent in D/D- than L/D-reared Rs1KO animals. We compared photoreceptor development using Rho, Rs1, and Psd95 expression, and these were similar; however, the outer segments (OSs) of D/D animals with Rho labeling at P12 were longer than L/D animals. Conclusions: The results showed that cavities formed at the same time in D/D and L/D XLRS rat pups, indicating that the timing of schisis formation is not light stimulus-driven but rather appears to be a result of developmental events. Cavity size tended to be larger under dark-rearing conditions in D/D animals, which could be due to the decreased rate of phagocytosis by the RPE in the dark, allowing for continued growth of the OSs without the usual shedding of the distal tip, a key mechanism behind dark adaptation in the retina. These results highlight the complexity of XLRS pathology; however, we found no evidence that light-driven metabolic activity accounted for schisis cavity formation.

X-linked juvenile retinoschisis (XLRS) is a hereditary retinal degeneration affecting young males caused by mutations in the retinoschisin (RS1) gene. We generated human induced pluripotent stem cells (hiPSCs) from XLRS patients and established three-dimensional retinal organoids (ROs) for disease investigation. This disease model recapitulates the characteristics of XLRS, exhibiting defects in RS1 protein production and photoreceptor cell development. XLRS ROs also revealed dysregulation of Na/K-ATPase due to RS1 deficiency and increased ERK signaling pathway activity. Transcriptomic analyses of XLRS ROs showed decreased expression of retinal cells, particularly photoreceptor cells. Furthermore, relevant recovery of the XLRS phenotype was observed when co-cultured with control ROs derived from healthy subject during the early stages of differentiation. In conclusion, our in vitro XLRS RO model presents a valuable tool for elucidating the pathophysiological mechanisms underlying XLRS, offering insights into disease progression. Additionally, this model serves as a robust platform for the development and optimization of targeted therapeutic strategies, potentially improving treatment outcomes for patients with XLRS.

Animal models of X-linked juvenile retinoschisis (XLRS) are valuable tools for understanding basic biochemical function of retinoschisin (RS1) protein and to investigate outcomes of preclinical efficacy and toxicity studies. In order to work with an eye larger than mouse, we generated and characterized an Rs1h−/y knockout rat model created by removing exon 3. This rat model expresses no normal RS1 protein. The model shares features of an early onset and more severe phenotype of human XLRS. The morphologic pathology includes schisis cavities at postnatal day 15 (p15), photoreceptors that are misplaced into the subretinal space and OPL, and a reduction of photoreceptor cell numbers by p21. By 6 mo age only 1–3 rows of photoreceptors nuclei remain, and the inner/outer segment layers and the OPL shows major changes. Electroretinogram recordings show functional loss with considerable reduction of both the a-wave and b-wave by p28, indicating early age loss and dysfunction of photoreceptors. The ratio of b-/a-wave amplitudes indicates impaired synaptic transmission to bipolar cells in addition. Supplementing the Rs1h−/y exon3-del retina with normal human RS1 protein using AAV8-RS1 delivery improved the retinal structure. This Rs1h−/y rat model provides a further tool to explore underlying mechanisms of XLRS pathology and to evaluate therapeutic intervention for the XLRS condition.

Background X‐linked retinoschisis (XLRS) is one type of retinal dystrophy leading to the schisis of the neural retina and causing reduced visual acuity. The study aimed to investigate the clinical manifestations and retinoschisin 1 (RS1) mutations in Chinese patients with early onset XLRS. Methods Thirty‐eight probands with early onset XLRS were recruited, comprehensive ophthalmic examination was performed. A targeted gene panel was used to test the RS1 mutations. Results All probands had RS1 hemizygous mutations including 16 known and 14 novel mutations. The median onset age was 2 years old (range 0.1–6 years). Probands with onset age ≤1 years. had more complications (retinal detachment and vitreous hemorrhage, p < 0.001), more mutations outside the discoidin domain and more non‐frameshift mutations than probands with onset age >1 years. Macular and peripheral involvement was present in 77.27% of probands, and inner and outer nuclear layer splitting were present in 53.57% of probands. Electroretinography showed an electronegative waveform. The relatively rare phenotypes of lamellar macular hole and macular hole were present in a unilateral eye in three probands. Conclusion In conclusion, the early onset XLRS developed more severe complications which need close monitoring and clinical manifestations illustrated here may facilitate the early diagnosis of retinoschisis. The median onset age was 2 years old (years, range 0.1–6 years). Probands with onset age (≤1 years) had more complications (retinal detachment and vitreous hemorrhage, p < 0.001), more mutations outside the discoidin domain and more non‐frameshift mutations than probands with onset age (>1 years). Macular and peripheral involvement was present in 77.27% of probands, and inner and outer nuclear layer splitting were present in 53.57% of probands.

Background X-linked retinoschisis (XLRS), due to mutations in the RS1 gene, is a common genetically determined form of macular degeneration. This report describes an unusual case of angle-closure glaucoma (ACG) with XLRS and discusses the treatment. Case presentation A 39-year-old Chinese man with an X chromosome-recessive inherited c.489G > A variant in the RS1 gene was diagnosed as XLRS and ACG, presenting with cystic macular lesions, shallow anterior chamber depth (ACD), and angle-closure with uncontrolled intraocular pressure (IOP). Malignant glaucoma occurred following trabeculectomy combining phacoemulsification with intraocular lens (IOL) implantation and goniosynechialysis. Subsequent anterior vitrectomy and irido-zonulo-hyaloid-vitrectomy (IZHV) effectively lowered IOP and deepened ACD, but the cystic cavity became larger. Conclusions There is a potential risk of malignant glaucoma in ACG patients with XLRS after filtering surgery. Although anterior vitrectomy can effectively resolve aqueous misdirection, the macular retinoschisis may get worse. Awareness of this risk may aid in surgical planning and postoperative management in these patients.