Sarthak Shah
MD Student with Scholarly Concentration in Molecular Basis of Medicine, expected graduation Spring 2026
All Publications
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Foveal Identification and Development in Prematurity-Implications on Zone Localization and Nutritional Supplementation.
Investigative ophthalmology & visual science
2025; 66 (11): 17
Abstract
Accurate identification of retinal Zone I in retinopathy of prematurity (ROP) is critical for treatment decisions and prognosis. Current definitions rely on identifying the macular center, limited by absence of the foveal light reflex (FLR) early in screening. Understanding factors influencing FLR development could improve zone localization and guide nutritional interventions. We sought to determine whether absolute infant weight gain independently predicts FLR development in premature infants, beyond postmenstrual age (PMA).Prospective observational cohort study conducted from November 2024 to March 2025 within a multicenter telemedicine-based ROP screening program (GHANAROP). Premature infants meeting ROP screening criteria, screened before 37 weeks PMA, who subsequently developed FLR identifiable on wide-field digital retinal imaging were included. Logistic regression assessed associations between FLR presence, PMA, and infant weight. Multivariate logistic regression with elastic net regularization evaluated combined predictive value of PMA and weight.Among 318 eyes, FLR was first identified at mean PMA of 35 0/7 weeks (low risk ROP) and 35 2/7 weeks (more than low risk ROP), and mean weight of 1723g (low risk) and 1565g (more than low risk). Univariate modeling found that each additional week of PMA increased odds of FLR presence by 44.6% (OR = 1.446; 95% CI, 1.371-1.524) and that each 200g increase in weight increased odds by 23.1% (OR = 1.231; 95% CI, 1.113-1.360). Multivariate modeling demonstrated PMA and weight as predictors of FLR development, achieving 84.8% predictive accuracy (Nagelkerke R² = 0.2783).Absolute infant weight independently predicts FLR development beyond PMA alone, highlighting opportunities for nutritional interventions to accelerate foveal maturation and potentially enhance visual outcomes.
View details for DOI 10.1167/iovs.66.11.17
View details for PubMedID 40772664
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Mapping the retinal resistivity with electrical impedance tomography for modeling of retinal stimulation
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2024
View details for Web of Science ID 001313316205324
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Telescreening for Retinopathy of Prematurity after 40 Weeks Postmenstrual Age
OPHTHALMOLOGY RETINA
2025; 9 (9): 921-923
Abstract
Of 111 infants without retinopathy of prematurity or prior treatment examined biweekly ≥40 weeks post-menstrual age, two developed reactivated stage 1 disease but spontaneously regressed. Biweekly examinations after 40 weeks may safely optimize healthcare resources.
View details for Web of Science ID 001568355700012
View details for PubMedID 40180314
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Reply to Comment on Long-Term Retinopathy of Prematurity Outcomes with Mandated Screening Interval and Grader Continuity at a High-Volume Quaternary Center.
American journal of ophthalmology
2025
View details for DOI 10.1016/j.ajo.2025.08.037
View details for PubMedID 40850450
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Long-Term Retinopathy of Prematurity Outcomes with Mandated Screening Interval and Grader Continuity at a High-Volume Quaternary Center.
American journal of ophthalmology
2025
Abstract
To summarize screening patterns and treatment rates from a quaternary teaching hospital and regional retinopathy of prematurity (ROP) referral center, highlighting mandated screening interval protocols and grader continuity.Retrospective cohort study METHODS, INTERVENTION, OR TESTING: A retrospective review and descriptive analysis of all patients who underwent inpatient ROP screening within a quaternary teaching hospital from 2013-2024. The screening model employed here used continuous screening by assigned graders without handoff and mandated screening interval with binocular indirect ophthalmoscopy (BIO). Variables compared included estimated gestational age, birth weight, weight at each screening, inborn vs outborn status, screening date and intervals, treatment, risk category, and location. ANOVA testing was performed for multiple comparisons, and two-sample T-testing was performed for binary comparisons.Incidence of Treatment-Warranted ROP and Retinal Detachment Rate RESULTS: Within the study period, 15,798 examinations occurred for 1,860 patients. 1,651 (88.8%) patients were only examined by one of four screeners. For each of the four screeners, between 98.1% to 99.3% of examination intervals were weekly or more often. Patients came from 34 different hospitals and 334 (18.0%) were outborn. Outborn (vs inborn) patients had significantly (p < 0.005) younger mean (±SD) EGA (27.8±3.0 weeks vs 29.0±3.0 weeks) and lower mean (±SD) birthweight (1066.9± 408 grams vs 1181.4 ± 416 grams). The screener who accounted for the most treatments also saw more high risk (nano- and micro-premature) infants, with a 19.4% treatment rate of these infants. Volume increased over time, but no seasonal trends were identified (p=0.51). A hundred (5.4%) required treatment, more often those who were outborn (4.6% inborn vs 9.0% outborn, p=0.002). None developed a retinal detachment.Twelve years of data from a BIO ROP screening model which relies on single screeners for continuity of care and mandated weekly screening demonstrated excellent outcomes. No infants succumbed to blindness from ROP within this screening model. Grader continuity may have contributed to lower intervention rates.
View details for DOI 10.1016/j.ajo.2025.07.017
View details for PubMedID 40706694
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Pseudo Iris Transillumination Defect
OPHTHALMIC SURGERY LASERS & IMAGING RETINA
2025; 56 (7): 446-447
View details for DOI 10.3928/23258160-20250324-01
View details for Web of Science ID 001528626500011
View details for PubMedID 40258195
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Retinopathy of Prematurity (ROP) in Kumasi, Ghana: A Telemedicine-Based Approach
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2025
View details for Web of Science ID 001559761700025
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Sea Fan Size and Location in Stage 3 Proliferative Sickle Cell Retinopathy in a West African Cohort
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2025
View details for Web of Science ID 001558648100035
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Cost-effectiveness of telemedicine-based screening programs for retinopathy of prematurity in Sub-Saharan Africa
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2025
View details for Web of Science ID 001560173300023
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Telescreening for Retinopathy of Prematurity After 40 Weeks Postmenstrual Age.
Ophthalmology. Retina
2025
Abstract
Of 111 infants without retinopathy of prematurity or prior treatment examined biweekly ≥40 weeks post-menstrual age, two developed reactivated stage 1 disease but spontaneously regressed. Biweekly examinations after 40 weeks may safely optimize healthcare resources.
View details for DOI 10.1016/j.oret.2025.03.025
View details for PubMedID 40180314
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Enhancing prosthetic vision by upgrade of a subretinal photovoltaic implant in situ.
Nature communications
2025; 16 (1): 2820
Abstract
In patients with atrophic age-related macular degeneration, subretinal photovoltaic implant (PRIMA) provided visual acuity up to 20/440, matching its 100 µm pixels size. Next-generation implants with smaller pixels should significantly improve the acuity. This study in rats evaluates removal of a subretinal implant, replacement with a newer device, and the resulting grating acuity in-vivo. Six weeks after the initial implantation with planar and 3-dimensional devices, the retina was re-detached, and the devices were successfully removed. Histology demonstrated a preserved inner nuclear layer. Re-implantation of new devices into the same location demonstrated retinal re-attachment to a new implant. New devices with 22 µm pixels increased the grating acuity from the 100 µm capability of PRIMA implants to 28 µm, reaching the limit of natural resolution in rats. Reimplanted devices exhibited the same stimulation threshold as for the first implantation of the same implants in a control group. This study demonstrates the feasibility of safely upgrading the subretinal photovoltaic implants to improve prosthetic visual acuity.
View details for DOI 10.1038/s41467-025-58084-y
View details for PubMedID 40118873
View details for PubMedCentralID PMC11928519
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Sickle cell retinopathy among Ghanaian high school students: a school-based screening.
BMJ global health
2024; 9 (12)
Abstract
Sickle cell disease (SCD) remains a significant health concern, particularly in Ghana and Sub-Saharan African countries. School-based ocular screenings provide a unique opportunity for early detection of sickle cell retinopathy (SCR).Students from five major schools in the Kumasi Metropolitan District of Ghana were included. Research assistants educated students on SCD and type 1 diabetes (T1DM) during school-wide assemblies, emphasising destigmatisation and vision health. Students completed questionnaires to self-report SCD or T1DM. Those who self-reported underwent in-depth interviews and dilated fundus exams (DFE).Of 17 987 total student population, 8168 students completed the survey (45.4% response rate) of which 2.4% of students were aware of their SCD status, while most 69.3% were unaware. No students reported having T1DM. 24 students identified as having SCD (14 haemoglobin SS and 10 HbSC) resulting in a prevalence of 0.07% and 0.05% for SS and SC, respectively. Among the SCD cohort, four had Proliferative SCR (PSCR). Of the students with stage 3 PSCR, one was 15 years old with SS genotype and bilateral stage 3 PSCR; another was 18 years old with SC disease, unilateral stage 3 PSCR. Only one SCD patient (SS genotype) had a history of previous DFE. 20.8% of SCD students were aware of SCD ocular complications and 75% felt uncomfortable sharing their SCD status.We conclude (1) an alarmingly low rate of self-reporting SCD (11× and 24× lower than expected for SS and SC-SCD, respectively), (2) low health literacy given 0% of students with SC-SCD had previously undergone a DFE and (3) 17% of students had PSCR and 8% of students had treatment-warranted PSCR (stage 3). These findings highlight the need for universal SCD screening, improved health education on the ocular complications of SCD and routine school-based vision screenings for patients with SCD.
View details for DOI 10.1136/bmjgh-2024-016896
View details for PubMedID 39937756
View details for PubMedCentralID PMC11664335
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3D electronic implants in subretinal space: Long-term follow-up in rodents.
Biomaterials
2024; 311: 122674
Abstract
Clinical results with photovoltaic subretinal prosthesis (PRIMA) demonstrated restoration of sight via electrical stimulation of the interneurons in degenerated retina, with resolution matching the 100 μm pixel size. Since scaling the pixels below 75 μm in the current bipolar planar geometry will significantly limit the penetration depth of the electric field and increase stimulation threshold, we explore the possibility of using smaller pixels based on a novel 3-dimensional honeycomb-shaped design. We assessed the long-term biocompatibility and stability of these arrays in rats by investigating the anatomical integration of the retina with flat and 3D implants and response to electrical stimulation over lifetime - up to 32-36 weeks post-implantation in aged rats. With both flat and 3D implants, signals elicited in the visual cortex decreased after the day of implantation by more than 3-fold, and gradually recovered over the next 12-16 weeks. With 25 μm high honeycomb walls, the majority of bipolar cells migrate into the wells, while amacrine and ganglion cells remain above the cavities, which is essential for selective network-mediated stimulation of the retina. Retinal thickness and full-field stimulation threshold with 40 μm-wide honeycomb pixels were comparable to those with planar devices - 0.05 mW/mm2 with 10 ms pulses. However, fewer cells from the inner nuclear layer migrated into the 20 μm-wide wells, and stimulation threshold increased over 12-16 weeks, before stabilizing at about 0.08 mW/mm2. Such threshold is still significantly lower than 1.8 mW/mm2 with a previous design of flat bipolar pixels, confirming the promise of the 3D honeycomb-based approach to high resolution subretinal prosthesis.
View details for DOI 10.1016/j.biomaterials.2024.122674
View details for PubMedID 38897028
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Enhancing Prosthetic Vision by Upgrade of a Subretinal Photovoltaic Implant in situ.
bioRxiv : the preprint server for biology
2024
Abstract
In patients with atrophic age-related macular degeneration, subretinal photovoltaic implant (PRIMA) provided visual acuity up to 20/440, matching its 100mum pixels size. Next-generation implants with smaller pixels should significantly improve the acuity. This study in rats evaluates removal of a subretinal implant, replacement with a newer device, and the resulting grating acuity in-vivo. Six weeks after the initial implantation with planar and 3-dimensional devices, the retina was re-detached, and the devices were successfully removed. Histology demonstrated a preserved inner nuclear layer. Re-implantation of new devices into the same location demonstrated retinal re-attachment to a new implant. New devices with 22mum pixels increased the grating acuity from the 100mum capability of PRIMA implants to 28mum, reaching the limit of natural resolution in rats. Reimplanted devices exhibited the same stimulation threshold as for the first implantation of the same implants in a control group. This study demonstrates the feasibility of safely upgrading the subretinal photovoltaic implants to improve prosthetic visual acuity.
View details for DOI 10.1101/2024.04.15.589465
View details for PubMedID 38659843
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Three-dimensional electro-neural interfaces electroplated on subretinal prostheses.
Journal of neural engineering
2024
Abstract
High-resolution retinal prosthetics offer partial sight restoration to patients blinded by retinal degenerative diseases through electrical stimulation of remaining neurons. Decreasing pixel size enables increasing prosthetic visual acuity, as demonstrated in animal models of retinal degeneration. However, scaling down the size of planar pixels is limited by the reduced penetration depth of the electric field in tissue. We investigated 3-dimensional structures on top of photovoltaic arrays for enhanced penetration of the electric field, permitting higher resolution implants. Approach. 3D COMSOL models of subretinal photovoltaic arrays were developed to accurately quantify the electrodynamics during stimulation and verified through comparison to flat photovoltaic arrays. Models were applied to optimize the design of 3D electrode structures (pillars and honeycombs). Return electrodes on honeycomb walls vertically align the electric field with bipolar cells for optimal stimulation. Pillars elevate the active electrode improving proximity to target neurons. The optimized 3D structures were electroplated onto existing flat subretinal prostheses based on modelling results. Main results. Simulations demonstrate that despite exposed conductive sidewalls, charge mostly flows via high-capacitance sputtered Iridium Oxide films topping the 3D structures. The 24 µm height of honeycomb structures was optimized for integration with the inner nuclear layers cells in the rat retina, whilst 35 µm tall pillars were optimized for penetrating the debris layer in human patients. Implantation of released 3D arrays demonstrates mechanical robustness with histology demonstrating successful integration of 3D structures with the rat retina in-vivo. Significance. Electroplated 3D honeycomb structures produce vertically oriented electric fields, providing low stimulation thresholds, high spatial resolution, and contrast for pixel sizes down to 20 µm. Pillar electrodes offer alternatives for extending past debris layers. Electroplating of 3D structures is compatible with the fabrication process of flat photovoltaic arrays, enabling much more efficient stimulation. .
View details for DOI 10.1088/1741-2552/ad2a37
View details for PubMedID 38364290