Elamipretide Topical Ophthalmic Solution for the Treatment of Subjects with Leber Hereditary Optic Neuropathy: A Randomized Trial.

PURPOSE: This study aimed to assess the safety, tolerability, and potential efficacy of topical elamipretide in patients affected with Leber hereditary optic neuropathy (LHON). DESIGN: This phase II, prospective, randomized, vehicle-controlled, single-center clinical trial involved administration of elamipretide 1% topical ophthalmic solution to patients with LHON over a 52-week double-masked treatment period, followed by an open-label extension (OLE) for up to 108 additional weeks of treatment. PARTICIPANTS: Twelve patients with LHON were included in this study. Patients aged 18 to 50 years with decreased vision for at least ≥ 1 year and ≤ 10 years, and a genetically confirmed diagnosis of m.11778G>A LHON were eligible for this trial. METHODS: For the first 52 weeks of the study, patients were randomized to 1 of 3 groups: elamipretide in both eyes or elamipretide in 1 eye (left eye and right eye were considered separate groups) and vehicle in the other eye, followed by an OLE in which both eyes were treated with elamipretide. MAIN OUTCOME MEASURES: The primary outcome measure was assessment of adverse events (AEs) from the administration of topical elamipretide, and the primary efficacy end point was change in best-corrected visual acuity (BCVA). Secondary outcome measures included changes in color vision, visual field mean deviation, and electrophysiological outcomes. RESULTS: Elamipretide was well tolerated with the majority of AEs being mild to moderate and resolving spontaneously. The change from baseline in BCVA in elamipretide-treated eyes was not significantly different from the vehicle eyes at any time point. Six of 12 subjects met the criteria for clinically relevant benefit (CRB). In the post hoc analysis, change from baseline in mean deviation in the central visual field was significantly greater in elamipretide-treated eyes versus the vehicle eyes. Compared with baseline, both treatment groups showed improvement in color discrimination and contrast sensitivity in the OLE. CONCLUSIONS: Elamipretide treatment was generally well tolerated, with no serious AEs reported. Although this study did not meet its primary BCVA efficacy end point, improvements across assessments on visual function during the OLE and the post hoc findings of the Humphrey automated visual field central region were encouraging and require further exploration. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Sensitivity and specificity of the uniform field electroretinogram in glaucoma detection in comparison to the pattern electroretinogram.

PURPOSE: To determine the ability of the photopic negative response (PhNR) of the uniform field electroretinogram (UF-ERG) to identify early glaucomatous changes in comparison to the checkerboard and bar stimuli of the pattern electroretinogram (PERG). METHODS: Forty-nine glaucoma patients were classified into two groups: glaucoma-suspect (23 eyes) and early to moderate glaucoma (30 eyes), based on their clinical examination and the results of standard automated perimetry. Thirty patients (30 eyes) with intraocular pressures (IOP) of 21 mmHg or less, with no history of reported high IOP, were included as controls. PERG and UF-ERG recordings were obtained on a Diagnosys D-341 Attaché-Envoy System. Visual field testing was done only for glaucoma-suspect and glaucoma patients. RESULTS: All three tests (PERG bar stimulus, PERG checkerboard stimulus and PhNR) displayed significantly prolonged peak times for glaucoma and glaucoma-suspect patients, with delays ranging from 7.8 to 14.8%, depending on the test. The PERG bar stimulus also showed a significantly lower N95 amplitude for both glaucoma groups (with reductions of 26.0% and 33.0% for glaucoma-suspect and glaucoma groups, respectively). The PERG checkerboard N95 amplitude component had high sensitivity for detecting glaucoma patients but a low specificity (97% and 37%, respectively; AUC = 0.61). Overall, the PhNR peak time showed the highest sensitivity and specificity (77% and 90%, respectively; AUC = 0.87). CONCLUSIONS: PERG bar stimuli and the PhNR of the UF-ERG can be used in the clinical setting to detect glaucoma-related changes in glaucoma-suspect and glaucoma patients. However, our data confirm that the PhNR peak time has the best combined sensitivity and specificity.

Efficacy and Safety of Intravitreal Gene Therapy for Leber Hereditary Optic Neuropathy Treated within 6 Months of Disease Onset.

PURPOSE: To evaluate the efficacy of a single intravitreal injection of rAAV2/2-ND4 in subjects with visual loss from Leber hereditary optic neuropathy (LHON). DESIGN: RESCUE is a multicenter, randomized, double-masked, sham-controlled, phase 3 clinical trial. PARTICIPANTS: Subjects with the m.11778G>A mitochondrial DNA mutation and vision loss ≤6 months from onset in 1 or both eyes were included. METHODS: Each subject's right eye was randomly assigned (1:1) to treatment with rAAV2/2-ND4 (single injection of 9 × 1010 viral genomes in 90 µl) or to sham injection. The left eye received the treatment not allocated to the right eye. MAIN OUTCOME MEASURES: The primary end point was the difference of the change from baseline in best-corrected visual acuity (BCVA) between rAAV2/2-ND4-treated and sham-treated eyes at week 48. Other outcome measures included contrast sensitivity, Humphrey visual field perimetry, retinal anatomic measures, and quality of life. Follow-up extended to week 96. RESULTS: Efficacy analysis included 38 subjects. Mean age was 36.8 years, and 82% were male. Mean duration of vision loss at time of treatment was 3.6 months and 3.9 months in the rAAV2/2-ND4-treated eyes and sham-treated eyes, respectively. Mean baseline logarithm of the minimum angle of resolution (logMAR) BCVA (standard deviation) was 1.31 (0.52) in rAAV2/2-ND4-treated eyes and 1.26 (0.62) in sham-treated eyes, with a range from -0.20 to 2.51. At week 48, the difference of the change in BCVA from baseline between rAAV2/2-ND4-treated and sham-treated eyes was -0.01 logMAR (P = 0.89); the primary end point of a -0.3 logMAR (15-letter) difference was not met. The mean BCVA for both groups deteriorated over the initial weeks, reaching the worst levels at week 24, followed by a plateau phase until week 48, and then an improvement of +10 and +9 Early Treatment Diabetic Retinopathy Study letters equivalent from the plateau level in the rAAV2/2-ND4-treated and sham-treated eyes, respectively. CONCLUSIONS: At 96 weeks after unilateral injection of rAAV2/2-ND4, LHON subjects carrying the m.11778G>A mutation treated within 6 months after vision loss achieved comparable visual outcomes in the injected and uninjected eyes.

Photopic negative response using a handheld mini-ganzfeld stimulator in healthy adults: normative values, intra- and inter-session variability.

PURPOSE: To determine normative values, intra- and inter-session variability for a range of parameters derived from the photopic negative response (PhNR) using a handheld mini-Ganzfeld stimulator in healthy normal adults. METHODS: Light-adapted flash full-field electroretinograms (ERGs) were recorded from healthy individuals with no visual complaints, visual acuity equal to or better than 0.0 logMAR (20/20 Snellen), and negative family history for visual diseases. ERGs were recorded from both eyes using a DTL® type fiber electrode after dilation of the pupils with instillation of 1 drop of tropicamide eye drops (1%). The full-field PhNR stimulus conditions were produced by a LED-based ColorBurst™ (Diagnosys LLC, Lowell, MA, USA) handheld stimulator. Red flashes of 1, 5 and 7 cd.s/m2 on a blue background of 10 cd/m2 were presented. A-wave, b-wave and PhNR amplitude (determined by both baseline to trough-BT and peak to trough-PT) and peak times were analyzed. Normal limits were determined as 5% percentile for amplitudes and 95% percentile for latencies. Intra- and inter-session variability were assessed with Wilcoxon signed-rank test, intraclass correlation coefficient (ICC) and the coefficient of variability (COV). RESULTS: Normative limits for PhNR amplitude (µV) using 1, 5 and 7 cd.s./m2 stimuli were, respectively: 20.81; 18.06 and 19.60 for BT and 69.11; 77.98; 76.51 for PT. Peak times (ms) normative limits for 1, 5 and 7 cd.s/m2 intensities were, respectively, 65.98; 78.20 and 77.96. Overall, intra-session variability assessed by coefficients of variation ranged from 1.35 to 10.28%. Inter-session variability disclosed significant intraclass correlation values for all PhNR parameters only for 1 cd.s/m2 stimuli. CONCLUSIONS: The normative values provided by this study are clinically helpful in the diagnosis of inner retinal disorders, especially those affecting retinal ganglion cells such as glaucoma and other optic neuropathies. Further studies, including a larger sample with variable age range would extend the validity of the current results.

Cross-Sectional Analysis of Baseline Visual Parameters in Subjects Recruited Into the RESCUE and REVERSE ND4-LHON Gene Therapy Studies.

OBJECTIVE: This report presents a cross-sectional analysis of the baseline characteristics of subjects with Leber hereditary optic neuropathy enrolled in the gene therapy trials RESCUE and REVERSE, to illustrate the evolution of visual parameters over the first year after vision loss. METHODS: RESCUE and REVERSE were 2 phase III clinical trials designed to assess the efficacy of rAAV2/2-ND4 gene therapy in ND4-LHON subjects. At enrollment, subjects had vision loss for ≤6 months in RESCUE, and between 6 and 12 months in REVERSE. Functional visual parameters (best-corrected visual acuity [BCVA], contrast sensitivity [CS], and Humphrey Visual Field [HVF]) and structural parameters assessed by spectral-domain optical coherence tomography were analyzed in both cohorts before treatment. The cross-sectional analysis of functional and anatomic parameters included the baseline values collected in all eyes at 2 different visits (Screening and Inclusion). RESULTS: Seventy-six subjects were included in total, 39 in RESCUE and 37 in REVERSE. Mean BCVA was significantly worse in RESCUE subjects compared with REVERSE subjects (1.29 and 1.61 LogMAR respectively, P = 0.0029). Similarly, mean CS and HVF were significantly more impaired in REVERSE vs RESCUE subjects (P < 0.005). The cross-sectional analysis showed that the monthly decrease in BCVA, ganglion cell layer macular volume, and retinal nerve fiber layer thickness was much more pronounced in the first 6 months after onset (+0.24 LogMAR, -0.06 mm3, and -6.00 µm respectively) than between 6 and 12 months after onset (+0.02 LogMAR, -0.01 mm3, and -0.43 µm respectively). CONCLUSION: LHON progresses rapidly in the first months following onset during the subacute phase, followed by relative stabilization during the dynamic phase.

Demographics of a Large International Population of Patients Affected by Leber's Hereditary Optic Neuropathy.

PURPOSE: To study the demographics of Leber's hereditary optic neuropathy (LHON) using a large international database of people affected by LHON. DESIGN: Cross-sectional study. PARTICIPANTS: One thousand five hundred seventeen people affected by LHON with a known pathogenic genetic mutation. METHODS: Self-reported genetic and demographic data were collected. The data were de-identified and then analyzed. MAIN OUTCOME MEASURES: Leber's hereditary optic neuropathy mutation, gender, age at vision loss onset, and geographical region. RESULTS: The data showed that both females and males can experience symptom onset at any age. We found a 3:1 male-to-female ratio. Interestingly, at younger than 5 years and older than 45 years, the male-to-female ratio of those becoming affected was approximately 1:1. A dramatic peak in age at onset of vision loss was found among males between 14 and 26 years of age. Disease onset in females occurred across all age groups, without any comparable dramatic peak of onset age. This study found that 10% of individuals become affected with LHON after 50 years of age. According to the literature, we found that the m.11778, m.14484, and m.3460 mutations were the most common LHON point mutations in both males and females, with a similar age at onset distribution. CONCLUSIONS: This was the largest study of LHON demographics to date. It showed that women carrying an LHON mutation are at higher risk of losing vision than is generally expected. Unlike the traditional 5:1 male-to-female ratio commonly reported in the literature, we found a 3:1 male-to-female ratio. Earlier studies may have harbored an ascertainment bias of overemphasizing the confirmation of this being a disease of young men. However, our data suggest that LHON is a disease that affects both females and males of all ages. This should prompt physicians to conduct genetic testing for LHON in all patients who meet the clinical criteria, regardless of whether they fit the demographics traditionally associated with the disease. Counseling about LHON should be offered to all maternal bloodline relatives, females and males of all ages, because they are at risk of sudden-onset legal blindness.

Pathophysiology of Conversion to Symptomatic Leber Hereditary Optic Neuropathy and Therapeutic Implications: a Review.

PURPOSE: Leber's hereditary optic neuropathy (LHON) is a genetic disease of the mitochondrial genome that mainly affects the retinal ganglion cells (RGC) of the inner retina resulting in central vision loss. New understandings in mitochondrial genetics are helping to elucidate the nuances of conversion and allow for new therapeutic options. RECENT FINDINGS: Appreciation of the mitochondrial fission-fusion balance has allowed for increased understanding of the cascade of events that leads to clinical conversion in LOHN. Mathematical and computational models have helped to interpret the role of ROS in conversion, both as oxidative agents and as signaling molecules for cell death. The conversion from the LHON carrier to the affected patient has been clinically characterized, but the pathophysiology is just beginning to be understood. External stressors alter the mitochondrial dynamics of RGCs, leading to ROS buildup, energy shortages, decreased biogenesis and increased mitophagy, and ultimately axon degeneration and ganglion cell death. New therapeutic alternatives targeting these newly understood pathophysiological changes in the mitochondria and directly addressing the genetic mutations involved in LHON are being developed.

William F. Hoyt: A Historical Perspective.

William Hoyt, MD, was one of the great men in the history of neuro-ophthalmology. He was a towering figure who influenced the field in all the ways one can. He did basic science. He did clinical science. He published an extraordinary number of seminal articles. He wrote the most important textbook in the field. He gave impetus to our neuro-ophthalmological societies and awards. However, he would insist that what he be most remembered for, was his inspired teaching of his many fellows. They carry on his legacy and influence.

Natural History of Conversion of Leber's Hereditary Optic Neuropathy: A Prospective Case Series.

PURPOSE: To illustrate the natural history of Leber's hereditary optic neuropathy (LHON). DESIGN: Prospective observational case series. PARTICIPANTS: The Soave-Brazil pedigree of m.11778G>A/ND4 mitochondrial DNA LHON mutation. METHODS: A prospectively acquired database of the Soave-Brazil pedigree was reviewed. Data from 285 individuals were included in the database over a 15-year period. The pedigree was reviewed for unaffected mutation carriers who converted to affected status, 6 patients with LHON were identified. The medical records were reviewed 1 year preconversion to 1 year postconversion for visual acuity (logarithm of the minimum angle of resolution [logMAR]), Humphrey Visual Field (HVF) mean deviation (MD), and retinal nerve fiber layer (RNFL) thickness, as measured by Cirrus (Carl Zeiss, Oberkochen, Germany) optic coherence tomography (OCT). The RNFL thickness values were normalized for age. Visual acuity, HVF, and processed RNFL data from each of the 12 eyes were then sorted into 2-month time periods relative to the date of conversion, within which they were averaged. MAIN OUTCOME MEASURES: The main outcome measures were visual acuity, HVF MD, and RNFL thickness. RESULTS: Decreased visual acuity preceded conversion by up to 2 months and then declined up to 8 months postconversion. Decrease in HVF MD occurred at least 4 months preceding conversion, after which values decreased until plateau at 6 to 8 months. Average RNFL thickness was above normal baseline thickness in all 4 quadrants as measured by OCT at the time of conversion. Increase in RNFL thickness preceded conversion as early as 4 to 6 months, peaked at conversion, and decreased until individual plateaus. The temporal quadrant was first to be involved, then the inferior and superior quadrants, and the nasal quadrant showed the latest and least changes. CONCLUSIONS: Subclinical changes preceded the date of conversion and may reflect the complicated nature of identifying the date of conversion in LHON. Early increases in RNFL preceding conversion suggest that structural changes precede clinically significant vision loss. Asynchronous quadrant involvement supports a previously published mathematical model. The natural history of LHON is not a subacute process, as previously believed, but progresses more slowly, taking up to 8 months to plateau.

An International Study of Emotional Response to Bilateral Vision Loss Using a Novel Graphical Online Assessment Tool.

BACKGROUND: Leber׳s hereditary optic neuropathy usually causes rapid bilateral blindness in young adults, and thus represents a unique and severe psychologic stressor. OBJECTIVE: We aimed to describe adjustment to this major life event, using a new tool to enhance recall of past affective states by using life event-related context. This is the largest (n = 116 with Leber׳s hereditary optic neuropathy), and first study reporting on the emotional aspects of this nontrauma cause of blindness. METHODS: We developed a new online survey tool that allowed study subjects to report their mood over a long period of time, corresponding with dates of relevant life events. RESULTS: The new method provided data of great richness for qualitative and quantitative analysis. Three groups were identified: a group in which majority of them had severe sadness at the point of vision loss followed by a period of recovery, a group whose sadness had not recovered, and a group for whom vision loss was not a major cause of sadness compared with other life events. We identified numerous factors that were important in psychologic recovery, and premorbid psychologic symptoms were more frequent in those who had not yet recovered. CONCLUSIONS: These data may assist behavioral health providers in identifying patients with vision loss to be at risk of mental health problems and in developing support and treatment interventions. We believe this new method has great potential for studying psychologic adjustment retrospectively.

A method for identifying color vision deficiency malingering.

PURPOSE: To propose a new test to identify color vision deficiency malingering. METHODS: An online survey was distributed to 130 truly color vision deficient participants and 160 participants willing to simulate color vision deficiency. The survey contained three sets of six color-adjusted versions of the standard Ishihara color plates each, as well as one set of six control plates. The plates that best discriminated both participant groups were selected for a "balanced" test emphasizing both sensitivity and specificity. A "specific" test that prioritized high specificity was also created by selecting from these plates. Statistical measures of the test (sensitivity, specificity, and Youden index) were assessed at each possible cut-off threshold, and a receiver operating characteristic (ROC) function with its area under the curve (AUC) charted. RESULTS: The redshift plate set was identified as having the highest difference of means between groups (-58%, CI: -64 to -52%), as well as the widest gap between group modes. Statistical measures of the "balanced" test show an optimal cut-off of at least two incorrectly identified plates to suggest malingering (Youden index: 0.773, sensitivity: 83.3%, specificity: 94.0%, AUC of ROC 0.918). The "specific" test was able to identify color vision deficiency simulators with a specificity of 100% when using a cut-off of at least two incorrectly identified plates (Youden index 0.599, sensitivity 59.9%, specificity 100%, AUC of ROC 0.881). CONCLUSIONS: Our proposed test for identifying color vision deficiency malingering demonstrates a high degree of reliability with AUCs of 0.918 and 0.881 for the "balanced" and "specific" tests, respectively. A cut-off threshold of at least two missed plates on the "specific" test was able to identify color vision deficiency simulators with 100% specificity.

Validity of Forced Eyelid Closure Test: A Novel Clinical Screening Test for Ocular Myasthenia Gravis.

BACKGROUND: Forced eyelid closure test (FECT) is a clinical screening test developed from the original Cogan lid twitch (CLT) sign to assist in the diagnosis of ocular myasthenia gravis (OMG), We evaluated the sensitivity and specificity of FECT compared with CLT and benchmarked to standard diagnostic tests. METHODS: This study was a retrospective chart review of 48 patients using electronic medical records of those that presented with ptosis and/or diplopia at Doheny Eye Institute, University of California, Los Angeles between February 2015 and April 2016. Patients without FECT testing were excluded. FECT and CLT results, and final diagnosis were recorded. To perform FECT, the patient was asked to squeeze his or her eyelids shut for 5-10 seconds then open quickly and fixate in primary position. The excessive upward overshoot of eyelids movement indicated a positive FECT. The test was performed by a neuro-ophthalmologist before establishing the diagnosis. Patients who had equivocal test results and/or inconclusive final diagnosis were excluded. RESULTS: Of the 48 patients studied, 18 patients (37.5%) had positive FECT; 15 of whom had a final diagnosis of OMG (83.3%). Of the 30 patients with negative FECT, 1 had OMG (3.3%). Of the 48 patients, 35 patients also had a documented CLT result (72.9%). CLT was positive in 11 of these 35 patients (31.4%), and 9 of these 11 had OMG (81.8%). Of the 24 patients with negative CLT, 2 of them had OMG (8.3%). Sensitivity and specificity of FECT were 94% and 91% (joint 95% confidence region: sensitivity × specificity = [0.70, 1] × [0.75, 1]). The relative true-positive fraction (rTPF) between FECT and CLT was 1.15; the relative false-positive fraction was 1.31. CONCLUSIONS: FECT is a simple clinical screening test with good sensitivity and specificity for OMG.

Subarachnoid Hemorrhage Following Angioplasty and Stenting in a Patient with Primitive Drainage Pattern of the Basal Vein of Rosenthal.

Severe visual loss may occur in patients with pseudotumor cerebri (PTC), also known as idiopathic intracranial hypertension. Transverse sinus stenosis is 1 cause of PTC syndrome. Although the role of transverse sinus stenosis in the pathogenesis of the disease remains controversial, recent case series of transverse sinus stenting have reported very high rates of symptom response and resolution of papilledema with improvement or at least stabilization of the visual fields and visual acuity (Ahmed et al., 2011).1 We report a previously unpublished complication of diffuse, nonaneurysmal subarachnoid hemorrhage following angioplasty and stenting in a patient with refractory PTC.

Correcting Finger Counting to Snellen Acuity.

In this paper, the authors describe an online tool with which to convert and thus quantify count finger measurements of visual acuity into Snellen equivalents. It is hoped that this tool allows for the re-interpretation of retrospectively collected data that provide visual acuity in terms of qualitative count finger measurements.

Detecting seasonal trends in optic neuritis within the Ottawa region.

OBJECTIVE: In this study we aim to determine seasonal patterns underlying optic neuritis (ON) onset that may provide valuable epidemiologic information and help delineate causative or protective factors. DESIGN: Single-centre retrospective chart review. METHODS: A database search of centralized electronic health records was completed using diagnostic codes employed at the Ottawa Eye Institute for data collection. Charts were reviewed for documentation supporting a diagnosis of ON falling into the following categories: multiple sclerosis ON and clinically isolated syndrome ON, myelin oligodendrocyte glycoprotein ON, neuromyelitis optica ON, and idiopathic ON. Date of onset, biological sex, and age were extracted from each chart. Data were analyzed for calculation of frequency by season and overall pooled seasonal trends of all cases of ON. RESULTS: From the 218 included patients with ON, there was no statistically significant seasonal correlation. The overall trend of ON was lowest in winter and spring (22% and 23%, respectively) and highest in summer and fall (28% and 27% respective). Divided further, multiple sclerosis ON or clinically isolated syndrome ON rates (n = 144) were lowest in the spring (21%) and highest in fall (29%); myelin oligodendrocyte glycoprotein ON rates (n = 25) were lowest in winter (16%) and highest in summer and fall (both at 32%); neuromyelitis optica ON rates (n = 16) were lowest in fall (12.5%) and highest in winter and summer (both at 31.25%); and idiopathic ON rates (n = 33) were lowest in fall (18%) and highest in spring (33%). CONCLUSIONS: The overall ON seasonal trend appears to have a predilection for the summer and fall months, which may be explained by warmer weather and viral infections as risk factors for multiple sclerosis relapse during those seasons.

Neuro-Ophthalmic Complications of COVID-19 Infection and Vaccination.

The COVID-19 pandemic has led to the identification of new disease phenotypes associated with infection by the SARS-CoV-2 virus. This includes multiple neuro-ophthalmological sequelae, which have been associated with COVID-19 infection and administration of COVID-19 vaccines. Some of these associations have a plausible pathophysiological link to the infection or vaccination but true causation has yet to be established. We review the literature for associations reported between COVID-19 infection or vaccination and neuro-ophthalmic sequelae and review the potential pathophysiological processes that may underlie these associations.

Indirect Comparison of Lenadogene Nolparvovec Gene Therapy Versus Natural History in Patients with Leber Hereditary Optic Neuropathy Carrying the m.11778G>A MT-ND4 Mutation.

INTRODUCTION: Lenadogene nolparvovec is a promising novel gene therapy for patients with Leber hereditary optic neuropathy (LHON) carrying the m.11778G>A ND4 mutation (MT-ND4). A previous pooled analysis of phase 3 studies showed an improvement in visual acuity of patients injected with lenadogene nolparvovec compared to natural history. Here, we report updated results by incorporating data from the latest phase 3 trial REFLECT in the pool, increasing the number of treated patients from 76 to 174. METHODS: The visual acuity of 174 MT-ND4-carrying patients with LHON injected in one or both eyes with lenadogene nolparvovec from four pooled phase 3 studies (REVERSE, RESCUE and their long-term extension trial RESTORE; and REFLECT trial) was compared to the spontaneous evolution of an external control group of 208 matched patients from 11 natural history studies. RESULTS: Treated patients showed a clinically relevant and sustained improvement in their visual acuity when compared to natural history. Mean improvement versus natural history was - 0.30 logMAR (+ 15 ETDRS letters equivalent) at last observation (P < 0.01) with a maximal follow-up of 3.9 years after injection. Most treated eyes were on-chart as compared to less than half of natural history eyes at 48 months after vision loss (89.6% versus 48.1%; P < 0.01) and at last observation (76.1% versus 44.4%; P < 0.01). When we adjusted for covariates of interest (gender, age of onset, ethnicity, and duration of follow-up), the estimated mean gain was - 0.43 logMAR (+ 21.5 ETDRS letters equivalent) versus natural history at last observation (P < 0.0001). Treatment effect was consistent across all phase 3 clinical trials. Analyses from REFLECT suggest a larger treatment effect in patients receiving bilateral injection compared to unilateral injection. CONCLUSION: The efficacy of lenadogene nolparvovec in improving visual acuity in MT-ND4 LHON was confirmed in a large cohort of patients, compared to the spontaneous natural history decline. Bilateral injection of gene therapy may offer added benefits over unilateral injection. TRIAL REGISTRATION NUMBERS: NCT02652780 (REVERSE); NCT02652767 (RESCUE); NCT03406104 (RESTORE); NCT03293524 (REFLECT); NCT03295071 (REALITY).