Stem cell technology has created exciting new possibilities for treating diseases. Stem cell therapy is complicated and new. Almost all valid stem cell therapies are still in the clinical trial stage, or even earlier.

The retina is very complex. It is the light-sensitive tissue at the back of the eye that is connected to the optic nerve. Deepest within the retina lies a layer of photoreceptors – rods and cones- that detect light sending a signal through the optic nerve to the brain that leads to our perception of vision. Some of the most devastating and incurable causes of blindness are due to the death of retinal cells.

The human retina has no innate ability to replace these cells once they are lost, being one reason why stem cells have drawn so much attention. Stem cell therapies may provide an option to replace the lost cells by either getting the retina to fix itself (regeneration) or introducing new cells obtained from an outside source (replacement) by transplantation. Scientists are working on both options, most commonly using pluripotent stem cells (PSC’s) – grown in the laboratory, which can theoretically make any cell in the entire body. Tremendous progress has been made in recent years. Specialized cell types, including photoreceptors, and RPE cells (the layer which nourishes photoreceptors) can now be produced from human PSC’s in a reliable manner.

Stem cells cannot just be injected anywhere in the eye and then expected to find where they need to go. Scientists are just beginning to tackle the question of developing truly effective methods of installing the new cells and getting them to connect properly and function. There is a great deal of excellent research being performed in the stem cell field that may be of considerable help to some patients in the foreseeable future.