In addition to the above, as animals (including humans) age, the normally clear lens of the eye becomes cloudy which is different from cataracts. People notice this because the dog has to keep his/her pupil open wider to let in the same amount of light. And when the light strikes it, it looks blue-ish white. But because dogs don't depend on vision as much as we humans do, they can compensate using their sense of smell and hearing. However  these animals may have more problems on grey or windy days that that lessen or destroy those scents or sounds. These animals will also get into problems if the owner rearranges furnishings or leaves things lying about.

It is possible she is developing cataracts and/or losing her eye sight.   Nothing to worry about really.   She will most likely lose her sight slowly and you will be amazed at well she adapts and gets around. 

You can make an appointment with a veterinary opthmologist which will dilate her eyes and do a detailed exam.  He will check for other eye problems and diseases while seeing if she does indeed have cataracts or not.  :-)   This is a speciality,  your regular vet will not have the equipment or training to do this eye exam...  :-)