How much vision can stem cells actually restore?
The short answer is: partial improvement, not a full cure. In a 2022 study of 28 eyes with advanced AMD, patients who received a subretinal implant of human amniotic membrane (which contains pluripotent stem cells) improved from an average visual acuity of roughly 20/1600 (counting fingers) to about 20/320 (able to see large letters on an eye chart) after 12 months [1]. That is a meaningful gain — enough to recognize faces or read large print — but still far from normal 20/20 vision. No patient in that study had a recurrence of the abnormal blood vessel growth that causes wet AMD over the year of follow-up [1].
A 2021 review of stem cell trials for retinal disease confirms this pattern: across multiple studies using retinal pigment epithelium (RPE) cells derived from embryonic or induced pluripotent stem cells, patients showed improved retinal function without severe side effects [9]. However, the improvements were modest, and the therapy is not yet a standard treatment. The same review notes that mesenchymal stem cells (from bone marrow) have also been used in clinical trials for AMD, with positive but limited outcomes [9].
How does stem cell therapy work for macular degeneration?
Age-related macular degeneration damages the retinal pigment epithelium (RPE), a layer of cells that supports the light-sensing photoreceptors. Stem cell therapy aims to replace or repair these damaged RPE cells. In the lab, scientists can turn induced pluripotent stem cells (iPSCs) — which are made from a patient's own skin or blood cells — into healthy RPE cells [4]. These lab-grown RPE cells can then be transplanted into the eye to restore the support structure for photoreceptors [4][9].
Another approach uses stem cells not to replace cells but to deliver protective factors. For example, bone marrow stem cells (BMSCs) have been shown in a 2025 cell-culture study to reduce the toxic effects of amyloid-beta (a protein linked to AMD) on RPE cells, restoring cell viability and normalizing genes involved in the visual cycle [2]. Similarly, exosomes (tiny vesicles) from mesenchymal stem cells were found in a 2023 animal study to protect RPE cells from oxidative stress — a key driver of dry AMD — by activating the Nrf2/Keap1 antioxidant pathway [8]. These studies suggest stem cells can both replace damaged tissue and provide ongoing protection.
What are the caveats and risks?
Stem cell therapy for AMD is still experimental. The largest review of clinical trials (2021) notes that while no severe side effects have been reported in early studies, the number of patients treated is small and follow-up times are short [9]. Ethical concerns and immune rejection remain potential issues, especially with embryonic stem cells, though induced pluripotent stem cells (made from the patient's own cells) avoid many of these problems [4][6].
Importantly, not all AMD patients are good candidates. The 2022 study that showed vision improvement used the therapy only in advanced cases — either wet AMD with abnormal blood vessels or geographic atrophy (the late stage of dry AMD) [1]. For earlier stages, current treatments like anti-VEGF injections for wet AMD are more established [7]. A 2023 study found that a non-stem-cell approach called Vision Protection Therapy (low-intensity laser) was more effective than standard care at preventing progression from dry to wet AMD, reducing the risk by about 5.7-fold [3]. This suggests that for some patients, other interventions may be more appropriate than stem cells at this point.
Finally, the cost and accessibility of stem cell therapy are major barriers. The procedures are complex, requiring specialized surgical techniques (like subretinal injection) and long-term follow-up [1][5]. Patients should be wary of unregulated clinics offering unproven stem cell treatments, as these can cause serious harm.
About These Sources
This answer is built on 9 peer-reviewed studies — published from 2021 to 2025, 3 from 2024 or later, 4 in Q1 journals, collectively cited 240 times — selected as the most relevant from 11 studies that passed quality screening, drawn from 63 papers retrieved from a database of over 500 million.
Sources used in this answer
Subretinal Transplant of Human Amniotic Membrane in Advanced Age-Related Macular Degeneration
In a 12-month study of 28 eyes with advanced AMD, subretinal implant of human amniotic membrane (a source of pluripotent stem cells) improved average visual acuity from 1.9 logMAR (roughly 20/1600) to 1.2 logMAR (roughly 20/320), with no recurrence of abnormal blood vessels.
Targeting Angiogenesis and Visual Cycle in Age-Related Macular Degeneration: The Role of Stem Cells and Vinpocetine
In a cell-culture model of AMD, bone marrow stem cells (BMSCs) restored viability of RPE cells damaged by amyloid-beta, downregulated the pro-angiogenic gene VEGF-A, and normalized visual cycle gene expression, with the strongest effects when combined with vinpocetine.
Vision protection therapy for prevention of neovascular age-related macular degeneration.
In a large database analysis of over 8,000 eyes, Vision Protection Therapy (low-intensity laser) reduced the risk of conversion from dry to wet AMD by about 5.7-fold compared to standard care, with better visual acuity maintained over time.
Human-induced pluripotent stem cells-derived retinal pigmented epithelium, a new horizon for cells-based therapies for age-related macular degeneration
This review discusses protocols for generating RPE cells from induced pluripotent stem cells (iPSCs) and argues that iPSCs avoid ethical and immunological issues of embryonic stem cells, making them a promising source for AMD cell therapy.
Treatment avenues for age-related macular degeneration: Breakthroughs and bottlenecks
This review covers cutting-edge treatments for AMD, including stem cell therapy and gene therapy, and notes that nanoparticulate drug delivery systems (e.g., polymeric nanoparticles, microneedles) can overcome ocular barriers to improve treatment efficacy.
Stem Cell Therapy In Retinal Diseases: Advances, Challenges, And Future Perspectives
This review summarizes stem cell therapy for retinal diseases, noting that while clinical trials show promise, challenges remain including ethical concerns, immune rejection, and delivery issues, with innovations in gene editing and biomaterials potentially improving outcomes.
The Role of Inflammation in Age-Related Macular Degeneration—Therapeutic Landscapes in Geographic Atrophy
This review of inflammation in AMD notes that while anti-VEGF therapies are standard for wet AMD, treatments for geographic atrophy (late dry AMD) are emerging, including complement inhibitors (e.g., pegcetacoplan, avacincaptad pegol) and stem cell therapies aimed at both slowing degeneration and restoring function.
Mesenchymal stem cell exosomes as nanotherapeutics for dry age-related macular degeneration
In a mouse model of dry AMD, mesenchymal stem cell exosomes (nanotherapeutics) protected RPE cells from oxidative damage by activating the Nrf2/Keap1 antioxidant pathway, reducing reactive oxygen species and preserving retinal structure.
Stem Cell Therapy for Retinal Degeneration: The Evidence to Date
This review of preclinical and clinical evidence for stem cell therapy in retinal degeneration reports that RPE cells derived from embryonic or induced pluripotent stem cells have shown improved retinal function in trials without severe side effects, and mesenchymal stem cells have been used for optic neuropathy and glaucoma with positive outcomes.