The following submission statement was provided by /u/Creepy_Toe2680:

State of lab grown eyes (not part of the article)

Regeneration of eyes as of 2019, June 25

There are still many challenges to address before we can use eyes grown in the lab for transplantation. The retina has a complicated circuitry comprised of nerve cells that are important for processing visual information into a perceived image.

It is not so simple to transplant an eye or individual cells taken from one eye and place them in another, expecting them to connect up perfectly with all the nerves responsible for normal vision.

For example, there are physical barriers that transplanted rods and cones would have to overcome to position themselves in the right place and connect with nerves in the host retina.

The disease processes that lead to blindness in the first place may have led to scarring and remodelling of the host retina, so that transplanted cells have nothing left to connect with.

It is easier to transplant other cell types in the eye that do not have these issues, like retinal pigment epithelial cells (RPE) which can also be grown from hESCs and iPSCs in the lab.

RPE cells are positioned next to the rod and cone photoreceptors, but they are not involved in the complicated circuitry of the retina. Their role is to supply nutrients to the photoreceptors, take away waste products, and recycle light sensitive molecules.

Some common causes of blindness, like age-related macular degeneration, are actually diseases of the RPE – photoreceptors get damaged as bystanders to the inflammation and bleeding that occur.

That is why clinical trials testing the efficacy of stem cell therapies are transplanting RPE cells and not photoreceptors. So far, the results seem promising and the transplantation of RPE cells appears to be safe.

in aug 2021

Scientists have managed to nurture small clumps of the human brain, giving them the ability to grow their own eyes, or at least two functionally integrated optic vesicles that respond to light.

April 13 , 2022

There are still numerous obstacles to overcome before lab-grown eyes may be used for transplantation. The retina comprises a complex circuitry made up of nerve cells that is responsible for converting visual data into perceptible images.

Transplanting an eye or individual cells from one eye into another and expecting them to connect flawlessly with all of the nerves necessary for normal vision is not straightforward.

So far, the results are encouraging, and RPE cell transplantation appears to be a safe procedure. Therefore, it’s not too far away when we may be able to grow “an eye in a dish” and transplant it to restore a blind person’s vision!

As of nov 2022

The focus is on usher syndrome

The genetic condition in question here is Usher syndrome, a rare birth defect that can leave a baby born deaf and with eyesight that degenerates by adulthood. By growing mini eyes from donors with and without Usher syndrome, the team was able to observe differences between the two. This could ultimately lead to clues for new treatments for the disease, as well as others like retinitis pigmentosa.

January 11, 2023 (this article)

"We wanted to use the cells from those organoids as replacement parts for the same types of cells that have been lost in the course of retinal diseases," says Gamm.

"But after being grown in a laboratory dish for months as compact clusters, the question remained – will the cells behave appropriately after we tease them apart? Because that is key to introducing them into a patient's eye."

"We've been quilting this story together in the lab, one piece at a time, to build confidence that we're headed in the right direction," says Gamm, from the University of Wisconsin-Madison.

"It's all leading, ultimately, to human clinical trials, which are the clear next step."

Further analysis revealed that the cell types that were most commonly forming synapses were the photoreceptors, commonly distinguished as rods and cones. That's encouraging, because these cell types are the ones lost in diseases such as retinitis pigmentosa and age-related macular degeneration.

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Edit: before people ask "why they are focusing on genetic defects rather than entirely focusing on growing eyes in lab?"

My understanding is:

They are trying to fix the smaller problems and then move on to the bigger ones, this makes it more sustainable and proves the technology is safe.

They also need more funds in order to continue their research.

The harder problems you try to fix the more investments are required.

Please reply to OP's comment here: https://old.reddit.com/r/Futurology/comments/10h2guk/labgrown_retinas_to_restore_vision_are_a_step/j5602ms/