Although I said "there seems to be no harm in trying cineraria eyedrops", there may be a word of caution. Cineraria Maritima belongs to a plant family called "Senecio", and is also referred to as "Senecio Bicolor". The "Senecio" family all contain toxic pyrrolizidine alkaloids (PA) which cause veno-occlusive liver disease. This is true also of the herb "comfrey" (otherwise known as "boneset" for its magical ability to heal bone fractures). In the past, comfrey leaves were eaten in salads or used to make tea, but as cases of liver failure were identified to due comfrey's high PA content, only external preparations of comfrey are now allowed to be sold. And one company in the US (HerbPharm) also manufactures a tincture of comfrey for external use from which all the PA have been removed.
So if we are going to use anticataract eyedrops made from Cineraria Maritima ("Senecio"), what about the PA content? Could there be a problem due to systemic absorption of PA from long-term use?
Now most "Cineraria" eyedrops are homeopathic preparations made with extreme dilutions. This should not present any problem as regards PA content: https://www.ingentaconnect.com/content/govi/pharmaz/2006/00000061/00000006/art00013?crawler=true
But what about "Cineraria" eyedrops of the "Mother Tincture", containing 10% upwards of the plant? This could be a problem.
Let's remember also, in Chinese medicine, "the liver governs the eyes", so adverse effects on the liver due to PA content do not bode well for eyesight. That said, many people attest improvement of cataract by using cineraria eyedrops.
Incidentally, PA are produced by many plant species as part of their natural defense against forage by animals. Also, PA can be found in other plant species that do not produce PA but grow alongside, by cross-contamination. Also, even honey sometimes contains PA, since bees collect pollen from such plants: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6032134/
Personally, for anticataract eyedrops made from Cineraria Maritima, I would stick with extreme homeopathic dilutions containing virtually none of the original plant material since it presents no risk. Or, since it is unlikely that the anticataract effect of Cineraria Maritima is related to its PA content, perhaps we could get some company to remove all the PA from "Cineraria Maritima", and make eyedrops from a PA-free mother tincture. How about that!