Sadat Yazdouni
Introduction
Blindness, a debilitating condition affecting millions of people globally, has seen substantial advancements in potential cures in recent years. Ground-breaking research in gene therapy, stem cell treatments, bionic eyes, and artificial intelligence is paving the way for restoring vision. Below, we explore the scientific principles underlying each of these emerging therapies, including their current progress and potential timelines for clinical application in humans.
Gene Therapy
Gene therapy offers a promising approach for treating inherited retinal diseases such as Leber Congenital Amaurosis (LCA) and Retinitis Pigmentosa (RP), caused by mutations in specific genes responsible for normal retinal function. In these diseases, mutations lead to the dysfunction or degeneration of photoreceptors in the retina, impairing the ability to process visual information.
Gene therapy works by delivering a healthy copy of the defective gene to the retina, where it can be taken up by retinal cells. This is typically achieved through the use of viral vectors, often Adeno-Associated Viruses (AAV), which are engineered to carry the therapeutic gene without causing disease. The vector is injected directly into the retina, and once inside the target retinal cells, the normal gene is expressed, compensating for the defective gene.
A notable example is Luxturna (voretigene neparvovec), a gene therapy approved for the treatment of RPE65 mutation-associated retinal dystrophy. The therapy involves introducing a functional RPE65 gene into retinal cells. RPE65 is an enzyme in the phototransduction pathway that enables photoreceptors to process light and produce vision. By restoring RPE65 expression, photoreceptors can function properly, halting or reversing degeneration caused by the mutation (1).
Research into CRISPR-Cas9 gene-editing technology is progressing, with early studies showing that this technology may offer a more precise approach by directly correcting mutations at the genetic level. Clinical trials are underway, but CRISPR-Cas9 applications for retinal diseases are still in early phases and may take several years before widespread use in humans (2).
Progress and Timeline
Gene therapy has already been successfully applied in humans for certain retinal diseases like RPE65 mutation-associated retinal dystrophy. As of 2025, clinical trials using CRISPR-Cas9 for gene editing in the retina are still in the early phase, with predictions that it may take another 5–10 years before it becomes widely available for human use (2).
Stem Cell Therapy
Stem cell therapy focuses on regenerating damaged retinal tissues by replacing lost or dysfunctional retinal cells. Diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP) lead to the progressive degeneration of photoreceptor cells, causing irreversible vision loss. Stem cells have the potential to regenerate retinal tissues by differentiating into retinal cell types, such as photoreceptors or retinal pigment epithelium (RPE) cells.
The process involves harvesting stem cells from sources such as induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs). These pluripotent stem cells have the ability to differentiate into various specialised cell types, including retinal cells, when provided with the appropriate biochemical signals. Once differentiated into retinal cells, these stem cells can be transplanted into the patient’s retina (3).
Progress and Timeline
Research into stem cell-based therapies for retinal degeneration has shown promising results in animal models, with clinical trials underway in humans. For example, studies involving iPSCs have demonstrated successful differentiation into retinal cells, and several clinical trials are exploring the safety and efficacy of retinal cell transplants in humans. However, integration of these cells into the retina and avoiding complications like immune rejection or tumour formation remain major challenges. It is expected that stem cell therapies for retinal diseases could be available for human clinical use in the next 5–10 years (3,4).
Bionic Eyes (Retinal Prosthesis)
Bionic eye technology, or retinal prostheses, provides a solution for patients whose photoreceptor cells have been irreversibly damaged but who still retain functional retinal ganglion cells, which transmit visual information from the retina to the brain. Instead of replacing damaged photoreceptors, bionic eyes work by bypassing them and directly stimulating the remaining retinal neurons using electronic devices.
The Argus II Retinal Prosthesis System is a well-known example. The system includes a microelectrode array implanted in the retina and a pair of glasses equipped with a small camera. The camera captures visual information in real-time, converts it into electrical signals, and transmits the signals to the microelectrode array implanted in the retina. These electrical signals stimulate the retinal ganglion cells, which then send visual information to the brain (5).
Progress and Timeline
The Argus II system has already been implanted in patients and is commercially available in certain regions, such as the US and Europe. While it is functional, the resolution of visual information is limited, and further advancements are needed to improve the system’s effectiveness. Ongoing research aims to enhance image resolution and reduce the invasiveness of the surgery. It is likely that improved versions of retinal prostheses, offering higher visual resolution, may be available in the next few years (6).
Artificial Intelligence (AI) in Vision Restoration
AI has become an important tool in the diagnosis and management of blindness, particularly in the early detection and monitoring of retinal diseases. AI-powered technologies can analyse vast amounts of retinal imaging data, such as optical coherence tomography (OCT) scans and fundus photographs, to detect early signs of conditions like diabetic retinopathy, macular degeneration, and glaucoma (7).
Machine learning algorithms are trained on large datasets of retinal images to identify patterns associated with disease progression. These algorithms can detect even the smallest abnormalities in the retina, allowing for earlier intervention and more effective treatment. AI models can assess retinal vasculature for signs of leakage or thickening in diabetic retinopathy or identify drusen deposits in the retina, a hallmark of macular degeneration (7).
Progress and Timeline
AI has already made significant strides in retinal disease detection, with multiple AI systems now in use for diagnostic purposes in clinical settings. The technology is advancing rapidly, with AI now capable of identifying complex retinal diseases with accuracy comparable to or exceeding human experts. AI’s role in personalised treatment planning is also growing. In the next 3–5 years, we may see further integration of AI into clinical workflows and a deeper integration with gene therapy and bionic eye systems to enhance the precision of treatments (8) .
Conclusion
The therapies discussed—gene therapy, stem cell treatments, bionic eyes, and artificial intelligence—represent diverse approaches to restoring sight. While gene therapy and stem cell treatments aim to address the underlying biological causes of blindness, bionic eyes offer technological solutions to bypass damaged retinal cells. AI enhances diagnosis and treatment precision. As of 2025, clinical trials are advancing, with some therapies already in clinical use and others expected to be available in the next 3–10 years. The continuous evolution of these technologies offers hope for the restoration of sight to those suffering from retinal diseases, potentially transforming the future of blindness treatment.
References
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