You might have seen our Secretary of State Hillary Rodham Clinton wearing rather thick glasses in recent photos. If you looked closely, you might have also noticed that the left eye lens was slightly less clear. Hey, when did she start wearing glasses? The truth is, she has always been very myopic (nearsighted). I have never treated her but can tell by the shape of her lenses that she is very nearsighted. This doesn’t happen overnight. It is likely she has worn contacts for most of her life. People who are severely myopic often wear contacts or even have laser vision correction to improve their vision as glasses tend to limit the best peripheral vision. Notice how her glasses thicken significantly on the edges as opposed to the center.
In Secretary Clinton’s case, she needs to wear them because they have been outfitted with a special prism to align her eyes. She is suffering from double vision, likely a result from either her fall or the vascular problem she had. Acute onset of double vision is typically caused from trauma to the skull, head injuries, intracerebral vascular events or tumors. In many cases, it is self- limited and will resolve on its own with time. In some cases, it is permanent.
In the initial phases of double vision, also known as diplopia, the Ophthalmologist will fit you with a temporary prism to align the eyes because they are not aligning on their own. This temporary prism is called a Fresnel (prounounced Fra-nel) prism which is pressed on to the glass and comes in different strengths. If the problem seems to be more permanent, these prisms can be ground into the glasses making them invisible to the observer. Unfortunately, contact lenses cannot be used to help double vision. Secretary Clinton could elect, however, to use the contact lenses to decrease the thickness and weight of the glasses and then use glasses in addition to the contacts to add prism.
Not all double vision is from pathology. It is quite common to see double images if you have significant astigmatism and it is not corrected. Once you get glasses, contacts or laser, the double goes away.
As we all saw, Secretary Clinton is tough. She will get through this temporary set-back with the strength and vitality she has demonstrated throughout her life. We all wish her well.