In our last post, we talked about some of the basics of dry eye. In this post, I am going to talk more about the specific types of dry eye disease. First, we will talk about aqueous deficient dry eye. This is the type of dry eye that is easiest to understand and really gets the most press. It also can be very serious and indicate an underlying disease such as Sjogren's disease which can go with rheumatoid arthritis, lupus, or just by itself. We talked about the three layers of the tear film, and this type of dry eye is when the tear film's thickest layer called the aqueous layer (basically the water layer of the tears) is decreased. There are a number of causes for this entity, but I will hit on a few of the major ones. The first one we always talk about is called idiopathic. This is just a fancy word for we do not know. This is the most common type of dry eye and it tends to coincide with age. There are most likely hormonal, environmental, and wear and tear factors that lead to this condition. The good news is that there is no underlying cause that we can identify, but the bad news is that dry eye is still present. The next type I would like to address is Sjogren's disease. This is an autoimmune disease which means the bodies immune system is actually the cause of the problem. The individual with Sjogren's may have the disease by itself or the antibodies may be cause by rheumatoid arthritis or other diseases along those lines. In order to have Sjogren's disease you must also have symptoms of other dry mucous membranes such as dry mouth. This is a particularly important form of dry eye to discover because finding it can sometimes prevent other manifestations of the underlying disease. The last type of aqueous deficient dry eye that I would like to discuss is LASIK related dry eye. LASIK cuts the nerves of the cornea, and they usually regenerate but some people are left with permanent decreased sensation. This can result in a multitude of factors such as reduced blink, but it can also result in the reduction of tears in the eye leading to chronic dry eye symptoms. The good news is there has never been more dry eye treatments than there are today. Next post will be about evaporative dry eye which can be a little more difficult to grasp conceptually.