A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: A Single-Arm Clinical Trial of Feasibility.

Purpose: To assess the feasibility of a second-generation (44-channel) suprachoroidal retinal prosthesis for provision of functional vision in recipients with end-stage retinitis pigmentosa (RP) over 2.7 years. Design: Prospective, single-arm, unmasked interventional clinical trial. Participants: Four participants, with advanced RP and bare-light perception vision. Methods: The 44-channel suprachoroidal retinal prosthesis was implanted in the worse-seeing eye. Device stability, functionality, and adverse events were investigated at approximately 12-week intervals up to 140 weeks (2.7 years) postdevice activation. Main Outcome Measures: Serious adverse event (SAE) reporting, visual response outcomes, functional vision outcomes, and quality-of-life outcomes. Results: All 4 participants (aged 39-66 years, 3 males) were successfully implanted in 2018, and there were no device-related SAEs over the duration of the study. A mild postoperative subretinal hemorrhage was detected in 2 recipients, which cleared spontaneously within 2 weeks. OCT confirmed device stability and position under the macula. Improvements in localization abilities were demonstrated for all 4 participants in screen-based, tabletop, and orientation and mobility tasks. In addition, 3 of 4 participants recorded improvements in motion discrimination and 2 of 4 participants recorded substantial improvements in spatial discrimination and identification of tabletop objects. Participants reported their unsupervised use of the device included exploring new environments, detecting people, and safely navigating around obstacles. A positive effect of the implant on participants' daily lives in their local environments was confirmed by an orientation and mobility assessor and participant self-report. Emotional well-being was not impacted by device implantation or usage. Conclusions: The completed clinical study demonstrates that the suprachoroidal prosthesis raises no safety concerns and provides improvements in functional vision, activities of daily living, and observer-rated quality of life. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Emerging treatments for geographic atrophy and the impact on clinical management of age-related macular degeneration.

Age-related macular degeneration (AMD) is a leading cause of vision impairment in people over 50 years of age and has a great impact on quality of life as it affects central vision. Although there have been treatments available for the neovascular form of late AMD for decades, until now there have not been treatments available for the atrophic form of late AMD - geographic atrophy (GA). Recently, treatments acting on the complement pathway have been approved by the United States Food and Drug Administration, with other jurisdictions such as Australia considering their approval. Furthermore, there are many more potential treatments for GA currently in clinical trials. However, unlike the treatments for neovascular AMD, where clinicians have treated virtually all patients presenting with exudation, the decision to treat those with GA will be more nuanced and individualised. Longitudinal retinal imaging will be one important asset that will help tremendously when counselling patients, as through these images, the growth pattern of the atrophy can be determined. Even without individual prior imaging history, there are other imaging clues to help predict growth rates and threats to the fovea, and hence imminent vision loss. Optometrists have a critical role in this new era where GA treatments will be available, as they are often the first to have contact with GA patients. Insightful, well-informed counselling and appropriate referral for those seeking more information on potential treatment to confirm the diagnosis and perform baseline imaging at a location likely to undertake any future treatment will ensure that appropriate patients have had the best workup to be individually managed once these treatments arrive in Australia.

Genetic Risk of Reticular Pseudodrusen in Age-Related Macular Degeneration: HTRA1 /lncRNA BX842242.1 dominates, with no evidence for Complement Cascade involvement.

Age-related macular degeneration (AMD) is a multifactorial retinal disease with a large genetic risk contribution. Reticular pseudodrusen (RPD) is a sub-phenotype of AMD with a high risk of progression to late vision threatening AMD. In a genome-wide association study of 2,165 AMD+/RPD+ and 4,181 AMD+/RPD-compared to 7,660 control participants, both chromosomes 1 ( CFH ) and 10 ( ARMS2/HTRA1 ) major AMD risk loci were reidentified. However association was only detected for the chromosome 10 locus when comparing AMD+/RPD+ to AMD+/RPD-cases. The chromosome 1 locus was notably absent. The chromosome 10 RPD risk region contains a long non-coding RNA (ENSG00000285955/BX842242.1) which colocalizes with genetic markers of retinal thickness. BX842242.1 has a strong retinal eQTL signal, pinpointing the parafoveal photoreceptor outer segment layer. Whole genome sequencing of phenotypically extreme RPD cases identified even stronger enrichment for the chromosome 10 risk genotype.

Deep Learning-Based Detection of Reticular Pseudodrusen in Age-Related Macular Degeneration on Optical Coherence Tomography.

Reticular pseudodrusen (RPD) signify a critical phenotype driving vision loss in age-related macular degeneration (AMD). Their detection is paramount in the clinical management of those with AMD, yet they remain challenging to reliably identify. We thus developed a deep learning (DL) model to segment RPD from 9,800 optical coherence tomography B-scans, and this model produced RPD segmentations that had higher agreement with four retinal specialists (Dice similarity coefficient [DSC]=0·76 [95% confidence interval [CI] 0·71-0·81]) than the agreement amongst the specialists (DSC=0·68, 95% CI=0·63-0·73; p <0·001). In five external test datasets consisting of 1,017 eyes from 812 individuals, the DL model detected RPD with a similar level of performance as two retinal specialists (area-under-the-curve of 0·94 [95% CI=0·92-0·97], 0·95 [95% CI=0·92-0·97] and 0·96 [95% CI=0·94-0·98] respectively; p ≥0·32). This DL model enables the automatic detection and quantification of RPD with expert-level performance, which we have made publicly available.

Nocturnal hypoxia and age-related macular degeneration.

BACKGROUND: Nocturnal hypoxia is common, under-diagnosed and is found in the same demographic at risk of age-related macular degeneration (AMD). The objective of this study was to determine any association between nocturnal hypoxia and AMD, its severity, and the high-risk sub-phenotype of reticular pseudodrusen (RPD). METHODS: This cross-sectional study included participants aged ≥50 years with AMD, or normal controls, exclusive of those on treatment for obstructive sleep apnoea. All participants had at home, overnight (up to 3 nights) pulse oximetry recordings and multimodal imaging to classify AMD. Classification of Obstructive Sleep Apnea (OSA) was determined based on oxygen desaturation index [ODI] with mild having values of 5-15 and moderate-to-severe >15. RESULTS: A total of 225 participants were included with 76% having AMD, of which 42% had coexistent RPD. Of the AMD participants, 53% had early/intermediate AMD, 30% had geographic atrophy (GA) and 17% had neovascular AMD (nAMD). Overall, mild or moderate-to-severe OSAwas not associated with an increased odds of having AMD nor AMD with RPD (p ≥ 0.180). However, moderate-to-severe OSA was associated with increased odds of having nAMD (odds ratio = 6.35; 95% confidence interval = 1.18 to 34.28; p = 0.032), but not early/intermediate AMD or GA, compared to controls (p ≥ 0.130). Mild OSA was not associated with differences in odds of having AMD of any severity (p ≥ 0.277). CONCLUSIONS: There was an association between nocturnal hypoxia as measured by the ODI and nAMD. Hence, nocturnal hypoxia may be an under-appreciated important modifiable risk factor for nAMD.

Chronic electrical stimulation with a peripheral suprachoroidal retinal implant: a preclinical safety study of neuroprotective stimulation.

Purpose: Extraocular electrical stimulation is known to provide neuroprotection for retinal cells in retinal and optic nerve diseases. Currently, the treatment approach requires patients to set up extraocular electrodes and stimulate potentially weekly due to the lack of an implantable stimulation device. Hence, a minimally-invasive implant was developed to provide chronic electrical stimulation to the retina, potentially improving patient compliance for long-term use. The aim of the present study was to determine the surgical and stimulation safety of this novel device designed for neuroprotective stimulation. Methods: Eight normally sighted adult feline subjects were monocularly implanted in the suprachoroidal space in the peripheral retina for 9-39 weeks. Charge balanced, biphasic, current pulses (100 µA, 500 µs pulse width and 50 pulses/s) were delivered continuously to platinum electrodes for 3-34 weeks. Electrode impedances were measured hourly. Retinal structure and function were assessed at 1-, 2-, 4-, 6- and 8-month using electroretinography, optical coherence tomography and fundus photography. Retina and fibrotic thickness were measured from histological sections. Randomized, blinded histopathological assessments of stimulated and non-stimulated retina were performed. Results: All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. The device position was stable after a post-surgery settling period. Median electrode impedance remained within a consistent range (5-10 kΩ) over time. There was no change in retinal thickness or function relative to baseline and fellow eyes. Fibrotic capsule thickness was equivalent between stimulated and non-stimulated tissue and helps to hold the device in place. There was no scarring, insertion trauma, necrosis, retinal damage or fibroblastic response in any retinal samples from implanted eyes, whilst 19% had a minimal histiocytic response, 19% had minimal to mild acute inflammation and 28% had minimal to mild chronic inflammation. Conclusion: Chronic suprathreshold electrical stimulation of the retina using a minimally invasive device evoked a mild tissue response and no adverse clinical findings. Peripheral suprachoroidal electrical stimulation with an implanted device could potentially be an alternative approach to transcorneal electrical stimulation for delivering neuroprotective stimulation.

Clinical performance of predicting late age-related macular degeneration development using multimodal imaging.

BACKGROUND: To examine whether the clinical performance of predicting late age-related macular degeneration (AMD) development is improved through using multimodal imaging (MMI) compared to using colour fundus photography (CFP) alone, and how this compares with a basic prediction model using well-established AMD risk factors. METHODS: Individuals with AMD in this study underwent MMI, including optical coherence tomography (OCT), fundus autofluorescence, near-infrared reflectance and CFP at baseline, and then at 6-monthly intervals for 3-years to determine MMI-defined late AMD development. Four retinal specialists independently assessed the likelihood that each eye at baseline would progress to MMI-defined late AMD over 3-years with CFP, and then with MMI. Predictive performance with CFP and MMI were compared to each other, and to a basic prediction model using age, presence of pigmentary abnormalities, and OCT-based drusen volume. RESULTS: The predictive performance of the clinicians using CFP [AUC = 0.75; 95% confidence interval (CI) = 0.68-0.82] improved when using MMI (AUC = 0.79; 95% CI = 0.72-0.85; p = 0.034). However, a basic prediction model outperformed clinicians using either CFP or MMI (AUC = 0.85; 95% CI = 0.78-91; p ≤ 0.002). CONCLUSIONS: Clinical performance for predicting late AMD development was improved by using MMI compared to CFP. However, a basic prediction model using well-established AMD risk factors outperformed retinal specialists, suggesting that such a model could further improve personalised counselling and monitoring of individuals with the early stages of AMD in clinical practice.

Post-Saccadic Oscillations of the Pupil and Lens Reduce Fixation Stability in Retinitis Pigmentosa and Age-Related Macular Degeneration.

Purpose: Post-saccadic oscillations (PSOs) reflect movements of gaze that result from motion of the pupil and lens relative to the eyeball rather than eyeball rotations. Here, we analyzed the characteristics of PSOs in subjects with age-related macular degeneration (AMD), retinitis pigmentosa (RP), and normal vision (NV). Our aim was to assess the differences in PSOs between people with vision loss and healthy controls because PSOs affect retinal image stability after each saccade. Methods: Participants completed a horizontal saccade task and their gaze was measured using a pupil-based eye tracker. Oscillations occurring in the 80 to 200 ms post-saccadic period were described with a damped oscillation model. We compared the amplitude, decay time constant, and frequency of the PSOs for the three different groups. We also examined the correlation between these PSO parameters and the amplitude, peak velocity, and final deceleration of the preceding saccades. Results: Subjects with vision loss (AMD, n = 6, and RP, n = 5) had larger oscillation amplitudes, longer decay constants, and lower frequencies than subjects with NV (n = 7). The oscillation amplitudes increased with increases in saccade deceleration in all three groups. The other PSO parameters, however, did not show consistent correlations with either saccade amplitude or peak velocity. Conclusions: Post-saccadic fixation stability in AMD and RP is reduced due to abnormal PSOs. The differences with respect to NV are not due to differences in saccade kinematics, suggesting that anatomic and neuronal variations affect the suspension of the iris and the lens in the patients' eyes.

Inter-night variability of in-home, overnight pulse oximetry screening in an asymptomatic older adult population.

PURPOSE: Obstructive sleep apnoea (OSA) is common, yet often undiagnosed. Self-administered, overnight pulse oximetry (OPO) could screen for OSA in asymptomatic, older populations. However, the inter-night variability of OPO in an asymptomatic, older population is unknown. We determined the inter-night variability of home OPO parameters in an older population and correlated with sleep questionnaires. METHODS: Participants > 50 years without a diagnosis of OSA undertook home OPO for three consecutive nights and completed two sleep questionnaires (STOP-BANG (SBQ) and Epworth Sleepiness Score (ESS)). Analysis was performed with linear mixed models and Spearman's correlation coefficient. RESULTS: There was no difference in oxygen desaturation index (ODI), MeanSpO2, MinimumSpO2, and time spent with SpO2 < 90% (T90) across two or three nights (P ≥ 0.282). However, the variability of all parameters across nights increased with the magnitude of departure from normal values (P ≤ 0.002). All OPO parameters were associated with age (P ≤ 0.034) and body mass index (P ≤ 0.049). There was a weak correlation between three OPO parameters and SBQ (absolute ρ = 0.22 to 0.32; P ≤ 0.021), but not ESS (P ≥ 0.254). CONCLUSION: Inter-night variability of home OPO was minimal when values were near-normal in an older population. However, as values depart from normal, the inter-night variability increases, indicating the need for multiple night recordings. Low correlation to sleep questionnaires suggest the need for more robust OSA questionnaires in an asymptomatic population.

HYPERREFLECTIVE FOCI NOT SEEN AS HYPERPIGMENTARY ABNORMALITIES ON COLOR FUNDUS PHOTOGRAPHS IN AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To investigate the prognostic value of quantifying optical coherence tomography (OCT)-defined hyperreflective foci (HRF) that do not correspond to hyperpigmentary abnormalities (HPAs) on color fundus photographs (CFPs)-HRF (OCT+/CFP-) -when considered in addition to HPA extent, for predicting late age-related macular degeneration development. This study sought to understand the impact of HRF (OCT+/CFP-) extent on visual sensitivity. METHODS: Two hundred eighty eyes from 140 participants with bilateral large drusen underwent imaging and microperimetry at baseline, and then 6-monthly for 3-years. The extent of HPAs on CFPs and HRF (OCT+/CFP-) on OCT was quantified at baseline. Predictive models for progression to late age-related macular degeneration, accounting for drusen volume and age, were developed using HPA extent, with and without HRF (OCT+/CFP-) extent. The association between HPA and HRF (OCT+/CFP-) extent with sector-based visual sensitivity was also evaluated. RESULTS: Incorporating HRF (OCT+/CFP-) extent did not improve the predictive performance for late age-related macular degeneration development ( P ≥ 0.32). Increasing HPA and HRF (OCT+/CFP-) extent in each sector were independently and significantly associated with reduced sector-based visual sensitivity ( P ≤ 0.004). CONCLUSION: The addition of HRF (OCT+/CFP-) extent to HPA extent did not improve the prediction of late age-related macular degeneration development. HRF (OCT+/CFP-) extent was also independently associated with local reductions in visual sensitivity, after accounting for HPAs.

Estimating Phosphene Locations Using Eye Movements of Suprachoroidal Retinal Prosthesis Users.

Purpose: Accurate mapping of phosphene locations from visual prostheses is vital to encode spatial information. This process may involve the subject pointing to evoked phosphene locations with their finger. Here, we demonstrate phosphene mapping for a retinal implant using eye movements and compare it with retinotopic electrode positions and previous results using conventional finger-based mapping. Methods: Three suprachoroidal retinal implant recipients (NCT03406416) indicated the spatial position of phosphenes. Electrodes were stimulated individually, and the subjects moved their finger (finger based) or their eyes (gaze based) to the perceived phosphene location. The distortion of the measured phosphene locations from the expected locations (retinotopic electrode locations) was characterized with Procrustes analysis. Results: The finger-based phosphene locations were compressed spatially relative to the expected locations all three subjects, but preserved the general retinotopic arrangement (scale factors ranged from 0.37 to 0.83). In two subjects, the gaze-based phosphene locations were similar to the expected locations (scale factors of 0.72 and 0.99). For the third subject, there was no apparent relationship between gaze-based phosphene locations and electrode locations (scale factor of 0.07). Conclusions: Gaze-based phosphene mapping was achievable in two of three tested retinal prosthesis subjects and their derived phosphene maps correlated well with the retinotopic electrode layout. A third subject could not produce a coherent gaze-based phosphene map, but this may have revealed that their phosphenes were indistinct spatially. Translational Relevance: Gaze-based phosphene mapping is a viable alternative to conventional finger-based mapping, but may not be suitable for all subjects.

The Saccade Main Sequence in Patients With Retinitis Pigmentosa and Advanced Age-Related Macular Degeneration.

Purpose: Most eye-movement studies in patients with visual field defects have examined the strategies that patients use while exploring a visual scene, but they have not investigated saccade kinematics. In healthy vision, saccade trajectories follow the remarkably stereotyped "main sequence": saccade duration increases linearly with saccade amplitude; peak velocity also increases linearly for small amplitudes, but approaches a saturation limit for large amplitudes. Recent theories propose that these relationships reflect the brain's attempt to optimize vision when planning eye movements. Therefore, in patients with bilateral retinal damage, saccadic behavior might differ to optimize vision under the constraints imposed by the visual field defects. Methods: We compared saccadic behavior of patients with central vision loss, due to age-related macular degeneration (AMD), and patients with peripheral vision loss, due to retinitis pigmentosa (RP), to that of controls with normal vision (NV) using a horizontal saccade task. Results: Both patient groups demonstrated deficits in saccade reaction times and target localization behavior, as well as altered saccade kinematics. Saccades were generally slower and the shape of the velocity profiles were often atypical, especially in the patients with RP. In the patients with AMD, the changes were far less dramatic. For both groups, saccade kinematics were affected most when the target was in the subjects' blind field. Conclusions: We conclude that defects of the central and peripheral retina have distinct effects on the saccade main sequence, and that visual inputs play an important role in planning the kinematics of a saccade.

Interobserver Agreement of Electrode to Retina Distance Measurements in a Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis.

Purpose: The electrode to retina (ER) distance is an important contributory factor to the safety and efficacy of a suprachoroidal retinal prosthesis. Measuring ER distance may be performed by different observers during multisite studies. The aim of this study was to assess the interobserver agreement in measuring ER distance. Methods: Three independent, trained observers measured ER distance from the center of each suprachoroidal electrode to the inner retinal pigment epithelium in spectral-domain optical coherence tomography (SD-OCT) B-scans. A total of 121 ER distance measurements from 77 B-scans collected over 5 months from one subject implanted with a second-generation 44-channel suprachoroidal retinal prosthesis (NCT03406416) were made by each observer. Results: ER distance ranged from 208 to 509 µm. Pearson's correlation coefficient (ρ) showed agreement of 0.99 (95% confidence interval [CI] = 0.98-0.99) in measuring ER for each pairwise comparison. The mean difference in ER distance between observers ranged from 2.4 to 6.4 µm with pairwise limits of agreement (95% CI) of ±20 µm (5.5% of mean). Intraclass correlation coefficient (ICC) showed agreement of 0.98 (95% CI = 0.97-0.99) between observers. Conclusions: There is high agreement in measuring ER distances for suprachoroidal retinal prostheses using our systematic approach between multiple, trained observers, supporting the use of a single observer for each image. Translational Relevance: High interobserver agreement outcomes indicate that multiple, trained observers can be used to take ER measurements across different images in suprachoroidal retinal prosthesis studies. This improves multisite study efficiency and gives confidence in interpreting results relating to the safety and efficacy of suprachoroidal retinal prostheses.

A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Long-Term Observation of the Electrode-Tissue Interface.

Purpose: To report the long-term observations of the electrode-tissue interface and perceptual stability in humans after chronic stimulation with a 44-channel suprachoroidal retinal implant. Methods: Four subjects (S1-4) with end-stage retinitis pigmentosa received the implant unilaterally (NCT03406416). Electrode impedances, electrode-retina distance (measured using optical coherence tomography imaging), and perceptual thresholds were monitored up to 181 weeks after implantation as the subjects used the prosthesis in the laboratory and in daily life. Stimulation charge density was limited to 32 µC/cm2 per phase. Results: Electrode impedances were stable longitudinally. The electrode-retina distances increased after surgery and then stabilized, and were well-described by an asymptotic exponential model. The stabilization of electrode-retina distances was variable between subjects, stabilizing after 45 weeks for S1, 63 weeks for S2, and 24 weeks for S3 (linear regression; Pgradient > 0.05). For S4, a statistically significant increase in electrode-retina distance persisted (P < 0.05), but by the study end point the rate of increase was clinically insignificant (exponential model: 0.33 µm/wk). Perceptual electrical thresholds were stable in one subject, decreased over time in two subjects (linear model; P < 0.05), and increased slightly in one subject but remained within the predefined charge limits (P = 0.02). Conclusions: Chronic stimulation with the suprachoroidal retinal prosthesis over 3 years resulted in stable impedances, small individual changes in perceptual electrical thresholds, and no clinically significant increase in electrode-retina distances after a period of settling after surgery. Translational Relevance: Chronic stimulation with the 44-channel suprachoroidal retinal implant with a charge density of up to 32 µC/cm2 per phase is suitable for long-term use in humans.

Cuticular Drusen in Age-Related Macular Degeneration: Association with Progression and Impact on Visual Sensitivity.

PURPOSE: To determine the prognostic significance and impact on visual function of the cuticular drusen phenotype in a cohort with intermediate age-related macular degeneration (AMD). DESIGN: Longitudinal, observational study. PARTICIPANTS: Participants aged 50 years or older, with bilateral large conventional drusen, without late AMD. METHODS: Multimodal imaging (MMI) and microperimetry were performed at baseline and then every 6 months for up to 3 years. Eyes were graded for the MMI-based presence of cuticular drusen at baseline. Color fundus photographs were used to grade for the presence of pigmentary abnormalities. OCT scans were used to calculate drusen volume. The associations between cuticular drusen and progression to MMI-defined late AMD (including OCT signs of atrophy) and the impact on visual sensitivity were examined with and without adjustment for the confounders of baseline age, pigmentary abnormalities, and drusen volume. MAIN OUTCOME MEASURES: Time to develop MMI-defined late AMD and change in mean visual sensitivity. RESULTS: A total of 280 eyes from 140 participants were included, with 70 eyes from 35 individuals (25%) having cuticular drusen at baseline. Cuticular drusen were not significantly associated with an increased rate of progression to late AMD with and without adjustment for confounders (P ≥ 0.784 for both). In an adjusted model, cuticular drusen were not associated with lower baseline visual sensitivity (P = 0.758) or a faster rate of visual sensitivity decline (P = 0.196). CONCLUSIONS: In a cohort with bilateral large conventional drusen, individuals with the cuticular drusen phenotype had neither a higher nor lower risk of developing late AMD over 3 years and were not associated with a difference in rate of visual sensitivity decline compared with those without this phenotype. As such, individuals with this phenotype currently warrant similar monitoring strategies as those with conventional drusen.

Genetics of reticular pseudodrusen in age-related macular degeneration.

Reticular pseudodrusen (RPD) are subretinal deposits that, when observed with age-related macular degeneration (AMD), form a distinct phenotype, often associated with late-stage disease. To date, RPD genetic risk associations overlap six well-established AMD-risk regions. Determining RPD-specific underlying genetic causes by using adequate imaging methods should improve our understanding of the pathophysiology of RPD.

Hyporeflective Cores within Drusen: Association with Progression of Age-Related Macular Degeneration and Impact on Visual Sensitivity.

PURPOSE: To examine the association between hyporeflective cores within drusen (HCD) and disease progression in age-related macular degeneration (AMD) and with visual function. DESIGN: Longitudinal observational study. PARTICIPANTS: Two hundred and eighty eyes from 140 participants with bilateral large drusen, without late AMD. METHODS: Multimodal imaging and microperimetry were performed at baseline and subsequently every 6 months for up to 3 years. Baseline OCT scans were graded for the presence of HCD and used to calculate drusen volume. The total area of the drusenoid lesions containing hyporeflective cores (HCD extent) on color fundus photographs (CFPs) was calculated. CFPs were also graded for the presence of pigmentary abnormalities. The association between HCD extent with progression to late AMD (including OCT signs of atrophy) and visual sensitivity measured using microperimetry at baseline and its rate of change over time was evaluated with and without adjustment for confounders of drusen volume, pigmentary abnormalities, and age. MAIN OUTCOME MEASURES: Time to develop late AMD and visual sensitivity. RESULTS: Twenty (7%) eyes from 12 (9%) individuals were found to have HCD at baseline, which was associated with a nonsignificantly increased rate of progression to late AMD (unadjusted P = 0.050). HCD extent was significantly associated with an increased rate of progression to late AMD (unadjusted P = 0.034) and lower visual sensitivity at baseline (unadjusted P < 0.001). However, these associations were no longer significant (P ≥ 0.264 for both) after adjusting for known risk factors for AMD progression. HCD extent was also not associated with a faster rate of visual sensitivity decline before the development of late AMD, with or without adjustment (P ≥ 0.674 for both). Increasing age and larger drusen volume were associated with HCD extent (P ≤ 0.041). CONCLUSIONS: In a cohort with bilateral large drusen, HCD presence and extent were not independently associated with an increased rate of progression to late AMD over 3 years, nor with lower visual sensitivity or an increased rate of visual sensitivity decline before the development of late AMD, after adjusting for known risk factors for disease progression.

A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Interim Clinical Trial Results.

Purpose: To report the initial safety and efficacy results of a second-generation (44-channel) suprachoroidal retinal prosthesis at 56 weeks after device activation. Methods: Four subjects, with advanced retinitis pigmentosa and bare-light perception only, enrolled in a phase II trial (NCT03406416). A 44-channel electrode array was implanted in a suprachoroidal pocket. Device stability, efficacy, and adverse events were investigated at 12-week intervals. Results: All four subjects were implanted successfully and there were no device-related serious adverse events. Color fundus photography indicated a mild postoperative subretinal hemorrhage in two recipients, which cleared spontaneously within 2 weeks. Optical coherence tomography confirmed device stability and position under the macula. Screen-based localization accuracy was significantly better for all subjects with device on versus device off. Two subjects were significantly better with the device on in a motion discrimination task at 7, 15, and 30°/s and in a spatial discrimination task at 0.033 cycles per degree. All subjects were more accurate with the device on than device off at walking toward a target on a modified door task, localizing and touching tabletop objects, and detecting obstacles in an obstacle avoidance task. A positive effect of the implant on subjects' daily lives was confirmed by an orientation and mobility assessor and subject self-report. Conclusions: These interim study data demonstrate that the suprachoroidal prosthesis is safe and provides significant improvements in functional vision, activities of daily living, and observer-rated quality of life. Translational Relevance: A suprachoroidal prosthesis can provide clinically useful artificial vision while maintaining a safe surgical profile.