Blind people regain a portion of their sight
In a recent study, researchers reported a 58-year-old man who managed to partially restore his eyesight after decades of blindness. This is made possible by optical gene therapy. Experts write of “a milestone on the path to gene therapies for a possible reversal of blindness”.
According to another Message From the Institute of Molecular and Clinical Ophthalmology Basel (IOB), an international research team was able to show that ophthalmic gene therapy helps restore a portion of vision in a patient who has become blind due to hereditary retinitis pigmentosa.
Often it is the fact that people who are blind are caused by a genetic disease in the photoreceptors of the eye. Like the University of Basel in one Message He writes that photoreceptors are light-sensitive cells in the retina of the eye that use so-called opsin proteins to convert light into electrical stimuli and to deliver visual information from the eye to the brain via the optic nerve.
However, in many hereditary diseases of the retina, the photoreceptors deteriorate and sufferers lose their ability to see.
The researchers are working with Professor Dr. Botond Roska from the University of Basel, founding director of the Institute of Molecular and Clinical Ophthalmology Basel (IOB), and Prof. Dr. José-Alain Sahel has been from the University of Pittsburgh for over ten years. For this, experts use so-called photo-gene therapies.
Partial restoration of vision
Optogenetics is a technique in which cells are genetically modified to produce light-sensitive proteins. Treating a patient who was completely blind due to hereditary retinitis pigmentosa disease showed promising results. Researchers write about it in the specialized journal.Nature Medicine“.
“The results of the study prove that optogenetic gene therapy for partial vision restoration is possible,” says Ruska.
In order to restore the retina’s sensitivity to light, researchers smuggled certain genes into so-called retinal ganglion cells so that they could produce the light-sensitive protein ChrimsonR. This special protein absorbs amber light, and is safer for retinal cells than the blue light often used in optogenetics.
Scientists have also developed special glasses with a camera. The camera records the environment and displays images, converting them to light wavelengths of amber color, on the retina.
Training with these glasses began about five months after the patient received the gene therapy. Production of the light-sensitive ChrimsonR protein in retinal cells has stabilized and after seven months it has reported signs of improved vision.
The patient can locate objects with special glasses
The test results showed: the patient was able to identify, touch and count objects on a white table before his eyes, but only with the help of special glasses. However, without glasses, he would not be able to do these exercises.
In another test, it should sense, locate and touch a large notebook or small box of staples. He successfully did this using the notebook in 36 of 39 independent studies (i.e., on 92 percent of all tests).
With the little box, we only succeeded in doing it 36 percent of the time. In another test, the man counted the cups on the table correctly 63% of the time.
During other attempts, he must press buttons to indicate whether or not there is glass on the table in front of him. The patient wore a hood with electrodes that recorded an electroencephalogram (EEG) of his brain activity.
An evaluation of the EEG measurements showed that activity in his brain’s visual cortex changed accordingly, depending on whether or not vitreous was present. This enabled the research team to confirm that brain activity is indeed associated with a visual object and that the retina is no longer blind.
The optic nerve must remain healthy
However, only patients whose optic nerve is still intact and who have lost their eyesight due to various types of photoreceptor neurodegenerative diseases are eligible for this type of blindness treatment, as José Alain Sahl asserts.
“It will take some time before this treatment is offered to patients,” the expert said.
The international research team included researchers from IOB, Institut de la Vision, Hôpital National des Quinze-Vingts in Paris, University of Pittsburgh, StreetLab and GenSight Biologics. (ad)
Author and source information
This text complies with the requirements of the specialized medical literature, medical guidelines and current studies and has been examined by medical professionals.
- University of Basel: Gene therapy allows blind people to partially see again (Accessed May 25, 2021), University of Basel
- Institute of Molecular and Clinical Ophthalmology Basel: Optogenetic Methods Restore Partial Vision for the Blind Patient, (Approv .: 25.05.2021), Institute of Molecular and Clinical Ophthalmology Basel
- José Alain Sahel, Elise Boulanger-Scama, Chloe Bagot, Angelo Arlio, Francesco Gallopi, Joseph N. Martel, Simona Degli Esposti, Alexandre Deluxe, Jean Baptiste de Saint-Hubert, Caroline de Montello, Emmanuel Gottman, Isabel Udo, Jeannes Duebel, Serge Picaud, Deniz Dalkara, Laure Blouin, Magali Taiel & Botond Roska: partial restoration of visual function in a blind patient after visual therapy; In: Natural Medicine (veröffentlicht: 24.05.2021), Nature Medicine
This article is for general guidance only and is not intended to be used for self-diagnosis or self-medication. He cannot replace a visit to the doctor.