Transparent domes useful for covering at least a lens located on a scope’s distal face, taking the form of a single layer membrane affixed to the distal end of the scope, a solid cap attachable to and detachable from the distal end of the scope, or an inflatable and deflatable balloon having an exterior wall for contacting at least the lens at the scope’s distal face. Each sensor supplies measurement data x1, x2. The voltage generator provides a write voltage at a given target level that varies in accordance with an amount of current detected by the memory cell array by using a reference voltage. Adjusting the pH of the aqueous concentrate to be within the range of 4. Thus, there is provided a soft intraocular lens that can be inserted into an eye from a further smaller incision, without damaging an optical function as much as possible.