Rishi wrote:Wonderful if it could work. Unfortunately, the behaviour of liquids will not permit it.
A lens works based on the refractive index of the material and the radii of curvature of its two sufaces being different, the values depending on the prescription. When a liquid drop is put on any surface it will spread to a film of uniform thickness and will not act as a lens.
Interesting aspect - I was thinking more of other reasons why it wouldn't work, like the impossibility to get the strength just right, or the eylids that would wipe the liquid away before it could shape into a lens.
But let's say we put a drop of liquid on a gass ball. Wouldn't it be possible to choose a makeup that condenses through the drying process? I mean, the behavior of liquids won't permit it, but the poster also suggested that it might solidify in the process. So if it contracts and turns into a solid, wouldn't it have a chance to be thicker on the inside than on the outside.
(PS: I assume that something that contracts while drying in your eye could cause quite some damage, so don't try this at home, at least not yet. )
All your concerns are valid and real. Your suggestion to produce a thickness variation by drying a film from outside-to-in on a spherical surface could well work provided that the film in contact with the sphere is adherent and not allowed to contract AND does not cover the entire sphere.
However, this will do two things.
One: If the drying leads to contraction of the dried film, you will get a negative power lens, while a positive power lens will result if the film expands on drying.
Two: The process of contraction or expansion will impose a tensile or compressive stress on the interface between the lens and the eye.
Further the requirement of adhesion negates the concept of dissolution later.
The poster's requirement can perhaps be met by using shape memory plastics. Make lenses that will retain their shape at body temperature in a shape memory soft plastic (Yet to be invented. There are some shape memory plastics, though not this kind), pack them in a suitable isotonic liquid in a tube as small spheres at a temperature below the shape transition temperature ( This exists for other shape memory medical devices already), and drop one in each eye like a jelly drop. It will dilate to the lens shape as it warms to the eye temperature.
However, such a lens cannot be water soluble for disposal.
All may not be lost. If one bathes his eye in a eye cup of cold water below the transition temperature, the lens will curl back into a sphere and drop off.
Is this easier than the current process of putting on a contact lens?