When something is said to cause “vascularization of the eyes,” I take it to mean that it causes blood vessels to grow in the eyes in a way it shouldn’t. What exactly does that do?
Warning! Pictures are not very pretty! Google image search for Vascularisation of the eye
Some parts of the eye are meant to have some blood vessels and be vascular, other components of the eye are not supposed to have blood vessels. They get their nutrition and waste removal by diffusion with the nearby areas that do have vessels.
The areas that are meant not to have vessels are the parts involved with image reception and clarity. Like the cornea or the lens. Blood vessels in these areas disrupt the clarity, so it will impair vision by distorting how light and images get into the eye to be processed.
Why the body does it? Because the area that does not has vessels is in some way damaged and signalling that it is damaged. One of the basic responses to damage is to increase vascular supply to the area in order to get the materials (cells) needed to “fix” the damage, and to remove some of the damage as well. Vascularization (or neovascularization) is a nonspecific healing response. Only that in some parts of the eye, normally you shouldn’t have any vessels, and thus they do cause trouble by interfering with the proper eye function (seeing).
Do you mean to say ‘neovascularization’ by any chance?
Although the term has different implications depending on the next, possibly its most common use refers to the growth of new blood vessels in the retina (back of the eye) which often occurs in people with diabetes and (usually older) people with macular degeneration. Indeed, it is a common cause of blindness in both those diseases and diabetic neovascularization is said to be the most common cause of blindness in North America.
The new blood vessels formed in diabetes are inherently unsound and weak, and often grow in the wrong plane. Together, those characteristics tend to cause the newly formed vessels to start bleeding with severe consequences on vision - if the bleeding is into the ‘center’ of the eye, blood gets in the way of incoming light. Beyond that, the presence of blood can elicit an inflammatory response which leads to scarring. The scars so-formed can attach to the retina and, as they contract with time, lift the retina off its supporting surface (retinal detachment). In fact, if the bleeding is in the plane of the retina, and not even into the ‘center’ of the eye, that bleeding can also detach the retina.
Even if the newly formed vessels don’t bleed, they can start to develop and grow in areas that are critical for vision and in that way, too, can impair one’s sight. For example, new (and useless) vessels can grow on the fovea which is critical for fine, central vision.
Although such new vessels can be ablated by laser photocoagulation, the hope is to prevent them from developing in the first place. In addition to maintaining ‘good glucose control’ (in diabetics, at least), they can also be prevented/treated by injections of anti-angiogenic drugs (antibodies, actually) directly into the eye (in ‘wet’ macular degeneration, if not diabetes), and also by pre-emptively lasering away those areas in the retina presumed to be the source of the angiogenic growth factors (i.e. hypoxic retina) that cause the new vessels to form (‘pan-retinal photocoagulation’).
I find it cool (from another perspective). Usually in animals, although they have (neo)vascularization of retina, corneal (neo)vascularization is more common (puncture wounds, ulcers, infections). Although it is not something that is wanted, temporary vascularization of the cornea in animals is not as dire as in humans, where like you said, the focus is on preventing them from developing.
Re: Neovascularization vs vascularization. I’ve heard arguments for using one vs the other. Typically for pathology we use neovascularization, as the places where we see it tend to already have some vessels. But some veterinary ophthalmologist and pathologists also point out that “hey, cornea is not supposed to have vessels”. You can then argue that at some point in development it did, but not after that. I tend to sometimes use one or the other, depending on audience.
What I mean is that it was stated that certain toxins can vascularize eyes. I wonder if it means the front of your eye (the white part,) or the retina at the back of the eye?
What stated that certain toxins can vascularize eyes?
The title of that article says retina…