Whole Eye Transplantation: Current Status
No, a whole eye cannot currently be transplanted in humans—only the cornea (the clear front surface of the eye) can be successfully transplanted to restore vision. 1
What Can Be Transplanted Today
Corneal Transplantation (Proven and Routine)
- Corneal transplantation is the only clinically established eye tissue transplant, with success rates exceeding 90% for nonvascularized central scars without other ocular damage 1
- Multiple techniques exist including penetrating keratoplasty (full-thickness), lamellar keratoplasty (partial-thickness), and endothelial keratoplasty 1
- Corneal allotransplantation enjoys considerable success in treating corneal blindness and is readily available in the United States and developed countries 1
Emerging Alternatives for Corneal Tissue
- Corneal xenotransplantation using porcine corneas is being investigated as an alternative to human donor corneas, with recent progress in primate studies moving closer to clinical trials 1
- Bio-engineered corneas using stem cells or cell lines are under development 1
Why Whole Eye Transplantation Is Not Possible
The Fundamental Barrier: Optic Nerve Regeneration
- Optic nerve regeneration and reintegration remain the overarching hurdles to whole eye transplantation 2
- Retinal ganglion cells are unable to regenerate, making vision restoration through whole eye transplantation currently impossible in mammals 3
- Even when experimental whole eye transplants have been performed in animal models, the optic nerve shows a neurodegeneration pattern rather than regeneration 4
Current State of Research
- Whole eye transplantation has been demonstrated as technically feasible in rodent models, with successful vascular anastomosis and short-term graft viability 4
- However, these experimental transplants show significant globe volume loss (36% reduction) and fail to achieve optic nerve regeneration necessary for vision 4
- Cold-blooded vertebrates have shown some recovery of vision after whole eye transplantation, but mammalian models have only demonstrated brief electroretinogram activity without functional vision restoration 3
Additional Challenges Beyond Nerve Regeneration
- The eye includes multiple tissues with distinct embryonic lineage and differential antigenicity, creating complex immunological challenges 4, 2
- Ischemia-reperfusion injury during transplantation affects both graft survival and any potential for optic nerve regeneration 2
- The unique immunology of the eye, including immune privilege and lymphatic drainage patterns, is not fully understood in the transplantation context 2
Clinical Bottom Line
For patients with blindness, focus on proven interventions: corneal transplantation for corneal disease (which accounts for approximately 10% of the 39 million cases of blindness worldwide), and emerging technologies like retinal prosthetics or optic nerve stimulation devices for retinal degenerative diseases 1, 5. Whole eye transplantation remains a theoretical future possibility requiring breakthroughs in optic nerve regeneration that do not currently exist 2, 3.