Publication Exclusive: Dry eye needs to be evaluated, managed before ocular surgery

Dry eye is a multifactorial disease of the tear film and ocular surface resulting in symptoms of discomfort, visual disturbance and tear film instability with potential ocular surface damage. It is accompanied by increased tear film osmolarity and ocular surface inflammation. This definition, given by the Dry Eye WorkShop in 2007, forms the basis of our understanding of dry eye. It also gives guidelines regarding grading of dry eye and treatment strategies for each grade of severity.

When it comes to ocular surgeries, managing dry eye in the perioperative period plays an important role in having a good outcome and a happy patient. Most of the patients that we operate for cataract are elderly with pre-existing minimal dry eye or a component of conjunctivochalasis, both of which can get worse after surgery. Apart from the routine use of a dry eye questionnaire and clinical evaluation with Schirmer’s test, corneal staining and tear breakup assessment to diagnose dry eye, newer modalities of investigations are now being used.

Hyperosmolarity plays an important role in the pathogenesis of dry eye. The advent of instruments to measure it in a simple and repeatable manner using the TearLab osmometer has allowed surgeons to include it in their preoperative and postoperative assessment of patients undergoing ocular surgery, especially cataract and LASIK. The need to measure tear film dynamics such as tear breakup time in a noninvasive manner, the tear meniscus height and quantifying the meibomian gland function using the meibography application in machines such as the Oculus Keratograph, or the assessment of the lipid layer of tears using LipiView technology (TearScience) is being attempted in centers that have access to this expensive equipment. Tear proteomics is another area with increased interest, and assessing the profile of inflammatory mediators in dry eye can give us a clue to the severity and can help in further understanding the disease. Recently, InflammaDry (RPS) a rapid in-office diagnosis kit, has been made available to ascertain the levels of MMP-9 in tears. The quality of vision of patients with dry eye can be assessed using instruments based on the double-pass aberrometry principle. Although the objective scatter index (OSI) can be affected even by cataract, the change in OSI over a period of a couple of minutes or before and after application of lubricants will help us understand the contribution of dryness to a patient’s poor quality of vision.

Click here to read the full commentary from Bhaskar Srinivasan, MD, and Dennis S.C. Lam, MD, FRCOphth, published in Ocular Surgery News APAO Edition, January 2016.