If you have symptoms of dry eye, then how do you confirm that you are suffering from dry eye related to Sjögren’s Disease?
The most basic diagnostic evaluation of dry eye is by direct observation and examination by an ophthalmologist (eye doctor). More advanced testing can look at not only your amount of tear production but also the components of the tears themselves. Normal tears are made up of water, oil, mucous, and many other beneficial proteins. All of these components are crucial for eye health.
The Schirmer test is a simple 5 minute test done to see how much tear production you have based on an established norm. One tiny strip of filter paper is placed in the pocket underneath each eye (the lower conjunctival sac) to measure the amount of tears they can soak up in that time frame. You just keep your eyes closed to let the test do its job. The thin strips of filter paper have measurements marked in mm. If 15mm or more become moist with tears then the test is considered normal. If less than 5mm of moisture is on the strip after 5 minutes then the test is considered abnormal and indicative of severe dry eye.
Corneal staining (also called a fluorescein eye stain test) is a method of evaluating the outer surface of the eye (the cornea). Dry eye can cause trauma to the cornea due to the lack of a nourishing and protective tear film layer. Fluorescein just means “dye”. Other stains that may be used are “rose bengal” or, more commonly, “lissamine green.” Dye is placed in your eye and then you blink to spread it around. The dyes are effective because they stain damaged cells on the eye. Damaged areas may be related to severe dry eye but other causes are possible too. Fluorescein is good for identifying corneal damage that may occur from dry eye if it is severe.
Fluorescein can also be used to evaluate the integrity of the tear film over your eye. Ideally your tears would evenly spread the dye over your eye surface area and this would be visible to your doctor under a high powered eye examination microscope. This fancy microscope is called a biomicroscope and it has a light source called a slit lamp. Despite the fancy name this is the equipment you have likely seen every time you go to the eye doctor and get a dilated eye exam. If you have an inadequate tear film layer over your eyes then that would result in the fluorescein dye not evenly coating the eye surface well and/or the dye would quickly “break up.” This happens when the tear film is not adequate to provide and maintain a smooth even protective layer over the eye.
Rose bengal or lissamine green (which is favored because it doesn’t burn and sting as much) stains are more useful for identifying mild or moderate dry eye by showing dry spots on not just the cornea but on the conjunctiva as well. The conjunctiva is the mucous membrane that covers the front of the eye and lines the inside of the eyelids.
Other testing measures and options for testing are becoming more available. Alone, none of this testing can directly say that you have Sjogren’s Disease. That is because Sjogren’s is not the only cause of dry or damaged eyes. However, these tests in conjunction with symptoms and other testing start to paint a picture. When enough things align and add up together then a diagnosis starts to form. That’s how you correlate your dry eye symptoms to sjögren’s. This multifactorial method is what contributes to the complexity of getting a diagnosis.
I will continue this blog series next week with a discussion on testing for dry mouth. Please visit my Facebook like page and comment on a post related to Sjögren’s Disease. What is your experience with dry eye?
Barbara Grubbs, Nurse Practitioner