Stem cell therapy for eye diseases in Turkey

What eye conditions can be treated with stem cell therapy?

Stem cell therapy is not a single treatment. Rather, it encompasses several cell types, delivery methods, and indications, each of which is at a different stage of clinical validation. The following conditions are the primary focus of current research and clinical practice in Turkey and internationally:

Age-related macular degeneration (AMD): Dry & geographic atrophy

Dry AMD and its advanced form, geographic atrophy, affect approximately 1.2 million people in the U.S. alone and have historically had no restorative treatment. Cell-based therapy using retinal pigment epithelium (RPE) cells derived from embryonic or induced pluripotent stem cells aims to replace the layer of cells whose degeneration drives AMD progression. Phase 1/2a trials have demonstrated safety and early vision improvements, and Phase 2b efficacy trials are ongoing. In January 2026, the OCU-410 gene therapy trial (a complementary approach) by Ocugen demonstrated that it slowed geographic atrophy lesion growth by 46%.

Retinitis pigmentosa (RP)

Retinitis pigmentosa affects approximately one in 2,000 people worldwide. It causes progressive photoreceptor death, leading to tunnel vision and, in many cases, total blindness. Unlike gene therapies that target specific mutations, stem cell approaches are mutation-agnostic; one protocol can benefit patients regardless of their underlying genetic variant. CD34+ autologous stem cells, UC-MSCs, and retinal progenitor cells have all demonstrated safety and measurable efficacy in Phase 1 and Phase 2 trials.

One particularly relevant study for patients considering treatment in Turkey is a 2020 investigation by Kahraman and Oner of 124 eyes with suprachoroidal UC-MSC injection. This study demonstrated improvements in visual acuity, visual field, and electroretinogram parameters at six months with no serious adverse events.

Stargardt macular dystrophy

Stargardt disease, the most common inherited macular degeneration in children and young adults, currently has no FDA-approved treatments. Astellas/ACT's hESC-derived RPE transplantation trials have been followed by multiple Phase 1/2 studies demonstrating safety, and larger efficacy trials are progressing. Patients with Stargardt disease are among those showing the strongest interest in accessing clinical trials, a category in which Turkey's specialized centers are actively involved.

Dry eye disease & limbal stem cell deficiency

Limbal stem cell deficiency, caused by chemical burns, Stevens-Johnson syndrome, or repeated surgeries, destroys the cornea's self-repair capacity. Cultured limbal stem cell transplantation is one of the most clinically established ocular stem cell procedures, restoring corneal clarity in a significant proportion of cases. Istanbul ophthalmologists list this as one of the most routinely performed stem cell–related procedures.

How do stem cells work in the eye?

The eye's relative immune privilege, compared to other organs, makes it an ideal target for cell-based therapies. This means transplanted cells are less likely to trigger rejection, allowing sustained therapeutic effects.

Three primary cell types are used, each targeting different layers of ocular tissue:

• RPE (Retinal Pigment Epithelium) cells: differentiated from embryonic (ESC) or induced pluripotent stem cells (iPSCs),these replace the support layer beneath the photoreceptors, the layer whose failure drives AMD and Stargardt.
• CD34+ autologous stem cells (from bone marrow): injected directly into the vitreous, these home in on damaged retinal tissue and stimulate regenerative signals, mutation-agnostic and self-sourced.
• Mesenchymal stem cells (MSCs) from umbilical cord or bone marrow: provide neuroprotective and anti-inflammatory support to surviving photoreceptors, slowing degeneration without necessarily replacing cells.
• Human retinal progenitor cells (hRPCs): designed to reactivate photoreceptors in RP, jCyte's Phase II safety trial in 30 patients confirmed safety; a Phase II/III trial followed in late 2025.

Clinical results & success rates: What the data shows

Stem cell therapy for eye diseases is no longer limited to theoretical research. Over the past few years, multiple clinical trials and meta-analyses have provided early but meaningful insights into its safety and potential effectiveness.

Here are some of the most relevant findings published between 2020 and 2025:

Most of these trials are Phase 1 or 2, which are designed primarily to establish safety with efficacy as a secondary endpoint. The figures above represent early-signal data and do not guarantee outcomes. Individual results depend on disease stage, cell type, delivery method, and specific retinal anatomy. Always request a personalized assessment before concluding population data.

Who is a candidate for ocular stem cell therapy?

Not every patient with a retinal condition is an appropriate candidate. The assessment process evaluates several factors before treatment is recommended:

You may be a candidate if:

• You have a confirmed diagnosis of AMD (geographic atrophy),retinitis pigmentosa, Stargardt disease, or limbal stem cell deficiency.
• Your disease is at a stage where sufficient residual retinal architecture remains for cells to integrate.
• You have undergone recent ophthalmic imaging (OCT, visual field testing, fundus photography) that can be reviewed for eligibility.
• You are in generally good health and free of active infection or uncontrolled systemic disease.
• Your expectations are aligned with current clinical evidence, partial preservation or modest improvement, not guaranteed restoration.

You may not be a candidate if:

• Your retina has reached advanced atrophy with extensive photoreceptor loss; few viable target cells remain.
• You have active intraocular inflammation or uncontrolled glaucoma.
• You are seeking a treatment with proven efficacy for your specific condition; most protocols remain in trial phases.

Risks, safety, and how they are managed

The most robust safety signal from the literature: UC Davis' 2024 Phase 1 trial found 90% cell viability, no infections, and no serious adverse events following intravitreal CD34+ injection in 7 RP patients. That said, all medical procedures carry risks, and informed consent requires an honest account of them.

Reported risks in clinical trials:

• Immune or inflammatory reaction: the eye's immune privilege reduces but does not eliminate this risk, typically managed with post-procedure corticosteroid drops
• Infection: any intraocular procedure carries a small infection risk (endophthalmitis); mitigated by sterile theatre conditions and prophylactic antibiotics
• Retinal detachment: a rare but serious complication monitored closely in the weeks following subretinal procedures
• Elevated intraocular pressure: transient and manageable with standard ophthalmological monitoring
• Theoretical oncogenic risk: relevant primarily for ESC-derived cells administered without adequate differentiation protocols; substantially mitigated with modern GMP processing

These risks are discussed explicitly during pre-treatment consultation at Turquie Santé partner hospitals, and all protocols require Ministry of Health approval.