Photoreceptor deficits appear at eye opening in Rs1 mutant mouse models of X-linked retinoschisis.

X-linked retinoschisis (XLRS) is an early onset degenerative retinal disease characterized by cystic lesions in the middle layers of the retina. These structural changes are accompanied by a loss of visual acuity and decreased contrast sensitivity. XLRS is caused by mutations in the gene Rs1 which encodes the secreted protein Retinoschisin 1. Young Rs1-mutant mouse models develop key hallmarks of XLRS including intraretinal schisis and abnormal electroretinograms. The electroretinogram (ERG) comprises activity of multiple cellular generators, and it is not known how and when each of these is impacted in Rs1 mutant mice. Here we use an ex vivo ERG system and pharmacological blockade to determine how ERG components generated by photoreceptors, ON-bipolar, and Müller glial cells are impacted in Rs1 mutants and to determine the time course of these changes. We report that ERG abnormalities begin near eye-opening and that all ERG components are involved.

Foveal Microstructure and Visual Outcomes after Pars Plana Vitrectomy in Patients with Different Types of Epiretinal Membrane Foveoschisis.

INTRODUCTION: The aim of this study was to evaluate the clinical characteristics and surgical outcomes of the epiretinal membrane foveoschisis (ERM-FS) with different morphological types. METHODS: This retrospective observational study reviewed 44 consecutive ERM-FS patients who underwent ERM surgery. According to the optical coherence tomography images, ERM-FS was classified into three groups: group A, FS crossed the fovea with the foveola elevated; group B, FS located at the foveal edges with a near-normal central foveal point thickness; and group C, FS with undermined foveal edges with a near-normal central foveal point thickness. RESULTS: There were 10 eyes in group A, 20 eyes in group B, and 14 eyes in group C. Preoperatively, eyes in group A had the best best-corrected visual acuity (BCVA), the thickest central foveal point thickness, and the highest ellipsoid zone (EZ) intact rate among the three groups. After surgery, a resolution of foveoschisis was observed in 40.0%, 45.0%, and 50.0% of the eyes in group A, group B, and group C (p = 0.928), respectively. BCVA was significantly improved postoperatively. Although there was no significant difference in BCVA among the three groups at 1 month postoperatively, BCVA of group A was the best at 4 and 10 months. Correlation analysis indicated that the type of ERM-FS, baseline BCVA, central foveal point thickness, and postoperative EZ continuity (all p < 0.05) were important factors for the final BCVA. CONCLUSIONS: The damage to the retinal structure and visual function was milder in group A ERM-FS. Our study emphasized the necessity of OCT-based subtyping in patients with ERM-FS.

X-Linked Retinoschisis: Novel Clinical Observations and Genetic Spectrum in 340 Patients.

PURPOSE: To describe the natural course, phenotype, and genotype of patients with X-linked retinoschisis (XLRS). DESIGN: Retrospective cohort study. PARTICIPANTS: Three hundred forty patients with XLRS from 178 presumably unrelated families. METHODS: This multicenter, retrospective cohort study reviewed medical records of patients with XLRS for medical history, symptoms, visual acuity (VA), ophthalmoscopy, full-field electroretinography, and retinal imaging (fundus photography, spectral-domain [SD] OCT, fundus autofluorescence). MAIN OUTCOME MEASURES: Age at onset, age at diagnosis, severity of visual impairment, annual visual decline, and electroretinography and imaging findings. RESULTS: Three hundred forty patients were included with a mean follow-up time of 13.2 years (range, 0.1-50.1 years). The median ages to reach mild visual impairment and low vision were 12 and 25 years, respectively. Severe visual impairment and blindness were observed predominantly in patients older than 40 years, with a predicted prevalence of 35% and 25%, respectively, at 60 years of age. The VA increased slightly during the first 2 decades of life and subsequently transitioned into an average annual decline of 0.44% (P < 0.001). No significant difference was found in decline of VA between variants that were predicted to be severe and mild (P = 0.239). The integrity of the ellipsoid zone (EZ) as well as the photoreceptor outer segment (PROS) length in the fovea on SD OCT correlated significantly with VA (Spearman's ρ = -0.759 [P < 0.001] and -0.592 [P = 0.012], respectively). Fifty-three different RS1 variants were found. The most common variants were the founder variant c.214G→A (p.(Glu72Lys)) (101 patients [38.7%]) and a deletion of exon 3 (38 patients [14.6%]). CONCLUSIONS: Large variabilities in phenotype and natural course of XLRS were seen in this study. In most patients, XLRS showed a slow deterioration starting in the second decade of life, suggesting an optimal window of opportunity for treatment within the first 3 decades of life. The integrity of EZ as well as the PROS length on SD OCT may be important in choosing optimal candidates for treatment and as potential structural end points in future therapeutic studies. No clear genotype-phenotype correlation was found.

Luminance Thresholds and Their Correlation With Retinal Structure in X-Linked Retinoschisis.

Purpose: To provide a comprehensive analysis of light- and dark-adapted luminance thresholds and their associations with retinal structure in X-linked retinoschisis (XLRS). Methods: Nine subjects with XLRS and 10 visually-normal individuals participated. Threshold was measured at 15 locations along the horizontal meridian of the visual field at several adaptation levels (5 × 10-5 to 50 cd/m2) after dark-adaptation. The relationship between threshold and adaptation level across the field was described using a standard "threshold-versus-illuminance" model. Optical coherence tomography images were obtained and segmented to quantify outer nuclear layer (ONL+) and outer segment (OS+) thickness. A linear structure-function model was used to describe the relationship between threshold and the product of ONL+ and OS+ thickness. Results: For peripheral field measurements, thresholds were generally normal for most subjects with XLRS. All subjects had perifoveal and parafoveal threshold elevations under dark-adapted and high illuminance conditions, with thresholds at moderate illuminances being closer to normal. For foveal measurements, seven of nine subjects with XLRS had normal dark-adapted thresholds, and all had abnormally elevated high illuminance thresholds. Threshold-versus-illuminance curves in the fovea, parafovea, and perifovea were abnormally steep for subjects with XLRS, appearing similar to the normal peripheral field shape. Under both dark- and light-adapted conditions, threshold was predicted by ONL+ × OS+ thickness at nearly all field locations. Conclusions: Threshold elevation in XLRS is complex, depending on both the adaptation level and the visual field location. The pattern of threshold-versus-illuminance suggests that macular function in XLRS is similar to the periphery of controls.

Spontaneous resolution of schitic cavities in XLRS.

X-linked retinoschisis (XLRS) is an inherited retinal condition that leads to schisis of the retina. In the past, treatment trials for XLRS have generally used OCT monitoring of the schitic cavities as the primary structural outcome measure and best corrected visual acuity as the primary functional outcome. Here, we report two cases of genetically confirmed XLRS with marked fluctuations in OCT morphology in the absence of treatment. Given this demonstration of spontaneous fluctuation in retinal structure on OCT in XLRS we suggest that alternative measures of retinal function should be used in future therapeutic trials in XLRS.

The Progression of Peripapillary Retinoschisis May Indicate the Progression of Glaucoma.

Purpose: To identify the temporal correlation between the increase in peripapillary retinoschisis (PPRS) and glaucoma progression during PPRS fluctuation. Methods: We performed a comparative clinical timeline analysis for PPRS and glaucomatous progression in eyes with PPRS. In particular, the interval between the increase in PPRS extent and glaucoma progression was analyzed. Temporal correlation was defined when the interval was less than one year between glaucoma progression and PPRS increase, including both de novo development and an increase in the amount of retinoschisis on serial optical coherence tomography. Results: We included 33 eyes of 30 patients, with an average follow-up period of 7.5 ± 3.0 years and a total of 253 glaucoma examinations. Glaucoma progression was observed in 21 of 33 eyes; 19 (90.5%) of the 21 eyes with glaucoma progression and 29 (74.4%) of the 39 episodes of PPRS increase showed temporal correlation. The de novo development of PPRS during the follow-up period over baseline PPRS was more frequently observed in the glaucoma progression group than in the no-progression group (P = 0.006). Conclusions: In glaucomatous eyes with PPRS, the increase in PPRS temporally correlated with glaucoma progression. Possible glaucoma progression may be considered around the time of increase and de novo development of PPRS.

STELLATE NONHEREDITARY IDIOPATHIC FOVEOMACULAR RETINOSCHISIS IN A PATIENT WITH MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: To present a case of unilateral stellate nonhereditary idiopathic foveomacular retinoschisis in a patient with macular telangiectasia (MacTel) Type 2. METHODS: Single-patient case report. RESULTS: A 61-year-old female white patient was referred to our clinic with metamorphopsia and reduction of visual acuity over a period of 2 months on her right eye. Ocular findings in her right eye included reduced best-corrected visual acuity of 20/63 Snellen, foveomacular retinoschisis with extension to the lower middle periphery, central elevation of the neurosensory retina, and macular telangiectasia (MacTel) Type 2. Other causes of foveomacular retinoschisis, such as glaucoma, myopic degeneration, optic or scleral pit, X-linked juvenile retinoschisis, degenerative retinoschisis, and vitreomacular traction, were ruled out. The patient had no history of niacin or taxane medication, which may cause rather similar appearing cases of cystoid macular edema without leakage in fluorescein angiography. Because of the unilateral presentation, uneventful medical history, female sex, and the absence of known hereditary diseases or retinal pathologies in the patient's family history, hereditary predisposition appears to be highly unlikely. CONCLUSION: To our knowledge, this is the first reported case of stellate nonhereditary idiopathic foveomacular retinoschisis in combination with MacTel Type 2. Whether or not MacTel Type 2 plays a role in the development of stellate nonhereditary idiopathic foveomacular retinoschisis or has an impact on its clinical course requires further investigation. Furthermore, we suggest a significant involvement of Henle fiber layer in the process of intraretinal expansion in optical coherence tomography, in accordance with the most recent published nomenclature.

Electronegative Electroretinograms in the United Arab Emirates.

PURPOSE: An electronegative electroretinogram (ERG), defined as having a b:a wave ratio ≤1 in the scotopic flash ERG response, indicates relative inner retinal dysfunction. Causes vary depending upon the study population. In the Arabian Gulf, where inherited retinal disease is relatively prevalent, common diagnoses associated with electronegative ERGs have not been described. In this study, we report the frequency and causes of electronegative ERGs in a cohort of Emirati patients with inherited retinal disease. METHODS: A retrospective review was performed of all full-field ERGs done for Emirati patients in the Ocular Genetics Service of Cleveland Clinic Abu Dhabi from January 2017 to December 2019. Those who had an electronegative ERG in at least one eye were included in the study. RESULTS: Out of 137 patients, 9 probands (6.6%) had an electronegative ERG. The mean age at presentation was 24 years (range 5-48 years), and five patients (55.6%) were male. The final clinical diagnoses were congenital stationary night blindness (CSNB) (two TRPM1-related and one Oguchi disease), X-linked retinoschisis (XLRS) (one genetically confirmed and two not genetically tested), cone-rod dystrophy (one CRX-related and one not genetically tested), and enhanced S-cone syndrome (ESCS) (one NRL-related). The one patient who did not have bilateral electronegative ERGs was a male with XLRS whose fellow eye had an unrecordable ERG. CONCLUSIONS: In this series of Emirati patients, an electronegative ERG was most commonly associated with the inherited retinal diseases recessive CSNB and XLRS. An electronegative ERG was noted in a case of NRL-related ESCS.

Full-Field Electroretinography, Pupillometry, and Luminance Thresholds in X-Linked Retinoschisis.

Purpose: To evaluate the nature and extent of functional abnormality in X-linked retinoschisis (XLRS) by comparing three dark-adapted, full-field measures: the electroretinogram (ERG), pupillary light reflex (PLR), and luminance threshold. Methods: ERGs, PLRs (pupil constriction due to light stimulation), and luminance thresholds were measured from seven XLRS subjects and from 10 normally sighted, age-similar controls. ERGs and PLRs were obtained for a range of flash strengths, and these data were fit with Naka-Rushton functions to derive the maximum saturated b-wave (Vmax) and PLR (Pmax) amplitudes. Additionally, semi-saturation constants were obtained for the b-wave (σ) and PLR (s). Values of 1/σ and 1/s provide sensitivity measures. Full-field, dark-adapted luminance thresholds were measured using 465-nm and 642-nm flash stimuli. Results: Vmax and 1/σ were significantly reduced in XLRS compared to the controls (both t ≥ 5.33, P < 0.001). In comparison, Pmax was normal in the XLRS subjects (t = 1.39, P = 0.19), but 1/s was reduced (t = 7.84, P < 0.001). Luminance thresholds for the control and XLRS groups did not differ significantly (F = 3.57, P = 0.08). Comparisons among measures indicated that pupil sensitivity was correlated with luminance threshold for the long- and short-wavelength stimuli (both, r ≥ 0.77, P ≤ 0.04). Correlations among all other measures were not statistically significant. Conclusions: The results indicate that the presumed bipolar cell dysfunction in XLRS, indicated by b-wave abnormalities, has complex downstream effects: Dark-adapted luminance threshold and maximum pupil responses are not significantly affected, but pupil sensitivity is reduced.

Clinical findings and RS1 genotype in 90 Chinese families with X-linked retinoschisis.

Purpose: X-linked retinoschisis (XLRS) is an early-onset retinal degenerative disorder caused by mutations in the RS1 gene. The objective of this study was to describe the clinical and genetic findings in 90 unrelated Chinese patients with XLRS. Methods: All patients underwent clinical examination, including best-corrected visual acuity (BCVA), slit-lamp biomicroscopy, fundus examination, and spectral domain-optical coherence tomography (SD-OCT). A combination of molecular screening methods, including Sanger-DNA sequencing of RS1 and targeted next-generation sequencing (TES), were used to detect mutations. In silico programs were used to analyze the pathogenicity of all the variants. Long-range PCR with subsequent DNA sequencing was employed to find the breakpoints of large deletions. Results: The 90 probands (mean age 17.29±12.94 years; 3-52 years) showed a variety of clinical phenotypes, and their average best correct visual acuity was 0.81±0.48 (logarithm of the minimal angle of resolution, 0-3). Of the 175 eyes analyzed, 140 (80%) had macular retinoschisis, 84 (48%) had peripheral retinoschisis, 28 (16%) had macular atrophy, and five (3%) had a normal macular structure. We identified 68 mutations in this cohort of patients, including 15 novel mutations. Most mutations (65%) were missense; the remaining null mutations included nonsense, splicing effect, frameshift indel, and large genomic DNA deletions. The 62 patients with missense mutations seemed to have relatively milder visual defects than the 28 patients with null mutations. Conclusions: Patients with RS1 mutations present profound phenotypic variability and show no clear genotype-phenotype correlations. Patients with null mutations tend to have more severe XLRS-related visual defects.

High myopic patients with and without foveoschisis: morphological and functional characteristics.

PURPOSE: Myopic foveoschisis (MF) is characterized by the splitting of the retinal layers in the fovea of patients with high myopia (HM). MF may progress into foveal detachment or macular hole formation with consequent loss of central vision. The aim of this study is to investigate morphological and functional changes of the macular region in myopic subjects with and without foveoschisis. DESIGN: Observational, cross-sectional, comparative study. METHODS: Forty-eight patients with HM and 24 healthy controls were evaluated by spectral domain-optical coherence tomography (SD-OCT), multifocal electroretinography (mfERG) and microperimetry (MP-1) tests to assess macular thickness, functionality and sensitivity values, respectively. The results of the diagnostic examinations were compared between three groups: HM patients with MF (N = 24), HM patients without MF (N = 24) and control group (CG) (N = 24). All statistical analyses were performed with STATA 14.0 (Collage Station, Texas, USA). One-way analysis of variance (ANOVA) followed by Tukey's post hoc test was used to analyze differences between groups unless specified; p values < 0.05 were considered as statistically significant. Gender distribution was compared by the Chi square test. RESULTS: The statistical analysis with one-way ANOVA followed by Tukey's post hoc test showed a significant increase in macular thickness in HM patients with MF when compared to both HM patients without MF and CG. Morphological changes were associated with functional impairment as demonstrated by the significant decrease in amplitude of the P1 wave and MP-1 sensitivity (p < 0.05), according to the anatomical landmarks. CONCLUSIONS: This study showed that the morphological changes observed in the central retina of HM patients with MF are associated with functional alterations. High-tech diagnostic tests such as SD-OCT, mfERG and MP-1 could be useful for management in complications of MF.

FUNCTIONAL AND STRUCTURAL OUTCOMES AFTER FOVEA-SPARING INTERNAL LIMITING MEMBRANE PEELING FOR MYOPIC MACULAR RETINOSCHISIS BY MICROPERIMETRY.

PURPOSE: To determine the morphological and physiological outcomes and safety of vitrectomy with fovea-sparing internal limiting membrane peeling for myopic macular retinoschisis (MRS). METHODS: Highly myopic eyes (refractive error greater than -8.0 diopters or an axial length longer than 26.5 mm) with MRS that underwent vitrectomy with fovea-sparing internal limiting membrane peeling were analyzed retrospectively. The best-corrected visual acuity, retinal morphology, and the central and paracentral retinal sensitivities at 2°/6° by microperimetry were evaluated before and after the surgery. Postoperative microscotomas were also determined. RESULTS: Thirty-three eyes with MRS; 16 eyes with and 17 eyes without a foveal retinal detachment, were studied. All 33 eyes had an improvement of MRS and foveal retinal detachment partially or completely after surgery, and none developed a full thickness macular hole. The postoperative best-corrected visual acuity, the central retinal sensitivity, and the retinal sensitivity at 2° were significantly better than the preoperative values. Sixteen eyes developed postoperative microscotomas at paracentral 2° and/or 6°. CONCLUSION: The results showed that vitrectomy with fovea-sparing internal limiting membrane peeling is an effective and safe method to treat an MRS regardless of the presence of a foveal retinal detachment. However, careful follow-up should be performed to detect postoperative microscotomas.

The role of Müller cells in tractional macular disorders: an optical coherence tomography study and physical model of mechanical force transmission.

BACKGROUND: To explore the role of foveal and parafoveal Müller cells in the morphology and pathophysiology of tractional macular disorders with a mathematical model of mechanical force transmission. METHODS: In this retrospective observational study, spectral-domain optical coherence tomography images of tractional lamellar macular holes and patients with myopic foveoschisis were reviewed and analysed with a mathematical model of force transmission. Parafoveal z-shaped Müller cells were modelled as a structure composed of three rigid rods, named R1, R2 and R3. The angle formed between the rods was referred to as θ . R1, R2 and R3 lengths as well as the variation of the angle θ were measured and correlated with best corrected visual acuity (BCVA). RESULTS: In tractional lamellar macular holes, there was a significant reduction of the angle θ towards the foveal centre (p<0.001). By contrast, there were no significant differences in θ in myopic foveoschisis (p=0.570). R2 segments were more vertical in myopic foveoschisis. There was a significant association between lower θ angles at 200 µm temporal and nasal to the fovea and lower BCVA (p<0.001 and p=0.005, respectively). The stiffness of parafoveal Müller cells was predicted to be function of the angle θ , and it grew very rapidly as the θ decreased. CONCLUSION: Parafoveal Müller cells in the Henle fibre layer may guarantee structural stability of the parafovea by increasing retinal compliance and resistance to mechanical stress. Small values of the angle θ were related to worse BCVA possibly due to damage to Müller cell processes and photoreceptor's axons.

Surgical outcomes of centripetal non-fovea-sparing internal limiting membrane peeling for myopic foveoschisis with and without foveal detachment: a follow-up of at least 3 years.

BACKGROUND: We evaluated the surgical outcomes of vitrectomy with non-fovea-sparing internal limiting membrane (ILM) peeling for myopic foveoschisis with a follow-up of at least 3 years. METHODS: In this retrospective study, 32 consecutive eyes with high myopia with or without foveal detachment underwent vitrectomy and centripetal, non-fovea-sparing ILM peeling with gas tamponade for myopic foveoschisis. Outcome measures were visual acuity (VA) and optical coherence tomography findings. RESULTS: Mean axial length was 29.39±1.92 mm; mean follow-up was 42.66 (±8.29) months. Foveoschisis and foveal detachment completely resolved in all eyes postoperatively. Mean central foveal thickness (CFT) improved significantly from 631.88±191.72 to 232.65±69.67 µm, and mean best-corrected visual acuity improved significantly from 0.90 (Snellen equivalent (SE), 20/160)±0.43 logarithm of minimum angle of resolution (logMAR) to 0.43 (SE, 20/54)±0.29 logMAR (both p<0.001; two-tailed, paired t-test). Eyes with foveal detachment (n=10) at baseline had thicker preoperative CFT (737.8±239.83 vs 583.73±147.78 µm; p=0.033) but thinner postoperative CFT (188.20±31.52 vs 252.86±73.29 µm; p=0.012). Eyes without foveal detachment at baseline had significantly better postoperative VA (0.33 (SE, 20/43)±0.18 vs 0.65 (SE, 20/86)±0.37 logMAR; p=0.002). No macular hole or other complications occurred during follow-up. CONCLUSION: Centripetal, non-fovea-sparing ILM peeling with gas tamponade may achieve myopic foveoschisis resolution and vision improvement without macular hole formation during at least 3-year follow-up.

Fovea-sparing internal limiting membrane peeling versus complete internal limiting membrane peeling for myopic traction maculopathy.

PURPOSE: To compare the outcomes of vitrectomy with fovea-sparing internal limiting membrane peeling (FSIP) and complete internal limiting membrane peeling (ILMP) for myopic traction maculopathy (MTM). STUDY DESIGN: A retrospective, observational study. PATIENTS AND METHODS: In this study, we included 22 eyes of 21 consecutive patients who underwent vitrectomy with FSIP or ILMP for MTM and were monitored for at least 6 months. Eleven eyes were treated with FSIP, and 11, with ILMP. RESULTS: With FSIP, the postoperative best-corrected visual acuity (BCVA) significantly improved from 0.61 (20/82) to 0.34 (20/44; P = .009) logarithm of the minimum angle of resolution (logMAR) units. With ILMP, the postoperative BCVA improved from 0.65 (20/89) to 0.52 (20/66) logMAR units, but was not significant (P = .106). The postoperative final central foveal thickness (CFT) reduced significantly after FSIP (from 557.6 to 128.8 µm, P = .003) and ILMP (from 547.3 to 130.3 µm, P = .008). The postoperative incidence of a macular hole was 0% (0/11 eyes) with FSIP and 27.3% (3/11 eyes) with ILMP. All patients with a macular hole had foveal detachment in association with a thin fovea preoperatively. With ILMP, postoperative BCVA with a macular hole worsened by -3.5 letters; in contrast, postoperative BCVA without a macular hole improved by +10.5 letters. With FSIP, postoperative BCVA without a macular hole significantly improved by +13.5 letters (P = .009). CONCLUSIONS: FSIP resulted in significant improvement in MTM and prevented postoperative macular hole development.

Cryotherapy and Pneumatic Retinopexy in Schisis-Related Retinal Detachment.

A 57-year-old female presented with macula-involving retinal detachment secondary to degenerative retinoschisis. She was repaired with transscleral cryotherapy to both inner and outer retinoschisis breaks followed by intravitreal sulfur hexafluoride (SF6) gas injection and anterior chamber paracentesis. Postoperative imaging at 4 months showed preserved fovea and completely attached retina. To the best of the authors' knowledge, this is the first report in the literature treating retinoschisis-related detachment with this minimally invasive technique without subretinal fluid drainage. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:791-794.].

Retinal Function in X-Linked Juvenile Retinoschisis.

Purpose: To assess retinal function in young patients with X-linked juvenile retinoschisis (XLRS), a disorder that is known to alter ERG postreceptor retinal components and also possibly photoreceptor components. Methods: ERG responses to full-field stimuli were recorded under scotopic and photopic conditions in 12 XLRS patients aged 1 to 15 (median 8) years. A- and b-wave amplitudes and implicit times were examined over a range of stimulus intensities. Rod and cone photoreceptor (SROD, RROD, SCONE, RCONE) and rod-driven postreceptor (log σ, VMAX) response parameters were calculated from the a- and b-waves. Data from XLRS patients were evaluated for significant change with age. Results: A- and b-wave amplitudes were smaller in XLRS patients compared with controls under both scotopic and photopic conditions. Saturated photoresponse amplitude (RROD), postreceptor b-wave (log σ), and saturated b-wave amplitude (VMAX) were significantly lower in XLRS patients than in controls; SROD did not differ between the two groups. SCONE and RCONE values were normal. In XLRS patients, neither a- and b-wave amplitudes nor calculated parameters (SROD, RROD, log σ, VMAX,SCONE, and RCONE) changed with age. Conclusions: In these young XLRS patients, RROD and a-wave amplitudes were significantly smaller than in controls. Thus, in addition to XLRS causing postreceptor dysfunction, an effect of XLRS on rod photoreceptors cannot be ignored.

Morphologic and functional outcomes of different optical coherence tomography patterns of myopic foveoschisis after vitrectomy and inner limiting membrane peeling.

OBJECTIVE: To evaluate the morphologic and functional outcomes of different optical coherence tomography (OCT) patterns of myopic foveoschisis after vitrectomy with Inner Limiting Membrane (ILM) peeling. METHODS: In 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. RESULTS: In 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. CONCLUSIONS: Vitrectomy with ILM peeling results in favourable anatomic and functional outcomes for different patterns of myopic foveoschisis.

Microperimetry in Three Inherited Retinal Disorders.

Objective: Microperimetry (MP) is used to assess visual sensitivity mediated by the central retina. As such, MP performance is a candidate outcome measure for gene therapy trials. Herein, we review MP results in three inherited retinal disorders for which gene therapy trials have been initiated-choroideremia, Stargardt disease, and X-linked juvenile retinoschisis. Each of these disorders typically presents in childhood and each has distinct effects on the central retina. Outcomes and Results: Our review indicates that microperimetry is feasible in each of these conditions. The MP sensitivity maps vary among conditions consistent with known effects of each of the three conditions. There is, however, within each of the three disorders considerable variability in fixation stability and in the pattern of sensitivity loss. Conclusions: Microperimetry is a valuable tool for monitoring functional aspects of central retina in an individual patient, especially in combination with other modalities such as OCT, autofluorescence, and acuity and thus may contribute to evaluating the efficacy of gene treatments. Variability of the MP parameters raises some cautions in application of MP as an outcome measure in treatment trials that may have small sample sizes. Nonetheless, we suspect that MP will continue to have a rightful place in future gene therapy trials.