Glaucoma in rodents in currently not treatable, although your vet can prescribe eye drops. Issues with visions may require care taken with cage layouts, to avoid sudden drops or changes. Winter White Hamsters are known for developing Glaucoma.
Rodents moult their fur from pup to adult where a baby coat is replaced with a smoother adult version. Some changes also occur as adults, Nutmeg gerbils for example, have quite dramatic colour changes and the lines of this can sometimes be seen quite clearly along their fur.
Winter White Hamsters will change coat colour as the light changes in winter, as a natural camouflage against the snow.