Dry Eye Diagnosis

As covered earlier by Dr. Wade, the symptoms of dry eye disease (DED) can be variable. Simply put, dry eyes can be separated into two categories: aqueous tear deficient (ATD) or dysfunctional tear syndrome (DTS). More commonly there is a combination of the two that I like to refer to as ocular surface disease (OSD). Lucky for you, as clinicians, we have several tools that will allow us determine what type of DED you have.

Steps In A Dry Eye Diagnosis

First is a review of your symptomatology. This is crucial to determining if you 1) have DED, and 2) what type you have. This determination can drive our treatment plan that is individual to you. In addition, we utilize various questionnaires that can help us hone in on your OSD.

Second is the ocular examination. We use a microscope (slit-lamp) to carefully examine the surface of the eye. When we look at your tear film we are looking to see the amount and health of your tears, how well they are working, and what effect they are having on the ocular surface (conjunctiva and cornea). Not only do we look at your tears, but we pay special attention to your eyelids. In your eyelids, there are oil producing glands called Meibomian Glands. These glands are responsible for creating a key component to the tear film: lipid. Human tears are very complex, but simply put, tears have 3 main components – water, mucus, and oil. I like to describe tears like salad dressing. In order to have tasty salad dressing, there needs to be a balance of oil, vinegar, and spices. Human tears are very much similar. In order for your tears to work properly, There needs to be the proper balance of the aqueous component (water), lipid component (from the Meibomian glands), and mucus component (image 1).

dry eye diagnosis
Image 1 – A relatively healthy meibiomian gland examination

If there is an imbalance in your tears, this will reflect in their function, and ultimately cause signs and symptoms of ocular surface disease. To highlight the appearance and function of the tears on the ocular surface, clinicians often use special stains that can aid us in determining the amount and function of your tears. Two of the most common stains are fluorescein and lissamine green. Each of these stains has particular characteristics that help determine the severity and extent of your ocular surface disease. For example, if you have significant staining near the bottom part of your cornea, your eyes maybe slightly open when you sleep, and therefore you may benefit from using an ointment at nighttime. Alternatively, if your tears appear to break up very quickly on your ocular surface, there is likely an imbalance in the tear composition that may benefit from institution of warm compresses along with tear replacement in the form of artificial tears.

Third is the use of ancillary testing to help confirm our clinical diagnosis. We are fortunate to have access to several commercially available OSD diagnostics at the Gavin Herbert Eye Institute. A brief description of if you have these diagnostics follows.

    1) Schrimer Testing – This is a very simple and common method of determining whether a patient has hey aqueous tear deficiency. Essentially, the eye is numbed and a sterile piece of special paper is placed in the lower outer corner of the eye. After a specified amount of time, the amount of tears is recorded, and if under a threshold value (generally 10 millimeters at five minutes) there is a high suspicion of aqueous tear deficiency. Treatments for this subtype of OSD will be covered in the next blog.
    2) Tear osmolarity – The most available tear osmolarity system is from TearLab. With this test, we look at the integrity of the tears by determining the osmolarity – essentially the ultrastucture of the tears. If the tear osmolarity is high (hyperosmolar), we know that the tears are not functioning properly. With proper institution of treatment, the osmolarity can normalize indicating a healthier tear film. This test is very noninvasive, requiring only a tear sample of 50 nanoliters – less than the volume of a single tear!
    3) InflammaDry – Inflammation has long been accepted as a hallmark of dry eye disease/ocular surface disease. As such, many of our treatment modalities have focused on treating ocular surface inflammation (discussed in the next installment of this blog). Prior to having access to the InflammaDry test, we would have to assume that there was inflammation involved in an individual’s OSD. Now, however, we can test the ocular surface for inflammatory markers and have an answer within just a few minutes. This test not only allows us to custom tailor treatments to an individual, but also we are able to see if our treatments are working. Again, this test is minimally invasive requiring the small sample of tears for testing.
      4) LipiView II – This test allows us to Image of the structure and function of the meibomian glands in vivo. The images obtained allow for several things. First, we are able to determine the extent of meibomian gland dysfunction. Second we are able to determine the extent of meibomain gland drop out (image 2).
dry eye diagnosis
Image 2 – Significant dropout of meibomian glands
    And third we are able to educate our patients so they can see the importance of treatment of their MGD. Again, this information can help us custom tailor treatment options for the individual patient.

In conclusion, as you can see diagnosis of ocular surface disease can be quite intricate. We are fortunate to be in and age where there has been significant improvements in our tools to help us better diagnose our patients and use this information to individualize treatment options. Stay tuned for the next installment of this blog focusing on treatments for ocular surface disease.


Sam Garg, MDSumit “Sam“ Garg, MD
Medical Director and Vice Chair of Clinical Ophthalmology
Assistant Professor of Ophthalmology
Gavin Herbert Eye Institute – UC Irvine

Cataract Surgery and Keratoconus


The eye works like a camera, specifically a digital camera. There is the front lens of the camera (cornea), the aperture (iris), the film (retina), and a cable to take the image to the brain (optic nerve). This “camera” also has an additional lens – the natural crystalline lens, which lies behind iris. This natural lens is flexible when we are young, allowing us to focus at distance then instantaneously up close. Around age 40-45, this natural lens starts to stiffen, necessitating the need for reading glasses for most people. This stiffening is the beginning of the aging process that eventually leads to formation of a cataract. We refer to the lens as a cataract when it becomes sufficiently cloudy to affect ones quality of vision.cataract surgery and keratoconus-Cataract diagram In general, cataract surgery is one of the safest and most successful of all surgeries performed. The basics of cataract surgery in eyes with keratoconus is very similar to non-keratoconic eyes.

Keratoconus (KC) affects this “camera” by causing the front lens (cornea) to bulge. This causes the optics to be distorted. In many cases, this can be corrected for with hard contact lenses (CL) or spectacles; in other cases a corneal transplant may be necessary. When it comes time for cataract surgery in the setting of KC, there are several factors that need to be considered.

Corneal Stability
The first thing to be considered is the stability of your cornea. In general, KC progresses more in your late teens to early twenties, and then stabilizes with age. A very exciting treatment for KC is collagen crosslinking. This treatment is meant to stiffen the cornea to prevent instability that is inherent to KC. This treatment promises to stop the progression of KC at a young age. Fortunately, with age, the cornea naturally crosslinks and stiffens, therefore when it comes time for cataract surgery, there is little chance of the progression of KC. Your doctor needs to choose the appropriate intraocular lens (IOL) to refocus your eye after surgery. Two of the most important factors in IOL selection are the length of your eye and the shape of your cornea. Long term CL wear can mold your cornea. It is important to assure that you stay out of your CLs long enough for your cornea to reach its natural shape. Depending on how long you have worn your CLs, it may take several months for the cornea to stabilize. This time can be challenging as your vision will be suboptimal (because you can’t wear CLs), and will be changing (as your cornea reaches its natural shape). When your cornea does stabilize, it is important to determine whether the topography (shape) is regular or irregular. This “regularity” is also known as astigmatism. If the astigmatism is regular, light is focused as a line – generally, this distortion can be fixed with glasses. However, if the astigmatism is irregular, light cannot be focused with glasses, and hard CLs are needed to provide optimal focusing. If you have had a corneal transplant, I generally recommend all your sutures to be removed to allow your new cornea to reach its natural shape.

IOL Selection
The second thing to be considered is the type of IOL. IOLs allow your doctor to refocus the optics of your eye after surgery. In many cases, the correct choice of IOL may decrease your dependence on glasses or CLs. There are several factors that are important when considering the correct IOL for a keratoconic patient. The amount and regularity of your astigmatism plays a very significant role in IOL selection. In general, there are four types of IOLs available in the US – monofocal, toric, pseudo-accomodating, and multifocal. In general I do not recommend multifocal IOLs in patients with KC. These IOLs allow for spectacle independence by spitting the light energy for distance and near, however, with an aberrated cornea (which is what happens in KC), these IOLs do not fare well. If there is a low amount of regular astigmatism or irregular astigmatism, your best bet is a monofocal IOL. This is the “standard” IOL that is covered by your health insurance. If you have higher amounts of astigmatism that your doctor determines is mostly regular, you may benefit from a toric (astigmatism-correcting) IOL. These IOLs can significant improve your uncorrected vision and really decrease your dependence on glasses. It is important to realize that monofocal and toric IOLs only correct vision at one distance. With a monofocal IOL you still can wear a CL to fine-tune your vision, however, with a toric IOL, in general you will need glasses for any residual error. There is a pseudo-accomodating toric IOL available, and this may be a good option if you are trying to decrease your dependence on glasses and correct some of your astigmatism. These IOLs are relatively new to the US market.

If You Had A Corneal Transplant
In the setting of a corneal transplant many of the same factors need to be considered – stability of the graft, choice of IOL, etc. In addition, the health of the graft has to be judged. Prior to cataract surgery in my patients with corneal transplants, I make sure to remove all of their sutures and give the cornea time to stabilize (just as if they were a CTL wearer). If you are a CL wearer, the same rule of being out of the TL until the topography is stable applies. The health of a transplant needs to be established prior to undergoing cataract surgery. The cornea has five main layers to it –cataract surgery and keratoconus-corneal structure the back layer (inside) is called the endothelium. This layer is responsible for “pumping” fluid out of the cornea, allowing it to stay clear. In all eyes there is a loss of endothelium cells with cataract surgery. I generally perform a “specular microscopy,” which allows me to visualize and quantify the corneal endothelium prior to surgery. This allows me to risk stratify you before your surgery. It is important to realize that corneal transplants have a lifespan and may have to be repeated in the future.

Keep in mind, there is some uncertainty in biometry (the process of selecting an IOL) in all eyes – this error can be higher in keratoconic eyes. This highlights why assuring stability is important. Equally important is picking the correct IOL for your situation. Also, keep in mind that I have discussed generalities in this article. Your individual case could be different. This is a conversation best left between you and your surgeon. In general, cataract surgery and keratoconus or a corneal transplant can be a very safe and effective way in restoring vision.

Sam Garg, MDSumit (Sam) Garg, MD
Interim Chair of Clinical Ophthalmology and Medical Director
Gavin Herbert Eye Institute at the University of California, Irvine