Dry Eye Before Cataract Surgery – Episode 23

Cataracts and dry eye have a tendency to worsen exponentially with age. In reality, it’s highly likely that over half of your population over the age of 60 has both of these conditions to one degree or another. But when it finally becomes time to consider cataract surgery, the treatment of dry eye, if not already, needs to become a major priority. In reality, dry eye is very common in our cataract patients. In one study looking at patients already scheduled for cataract surgery, 63% had a tear break up time of less than 5 seconds, 77% showed corneal staining, 49% of the eyes had a Schirmer’s strip less than 10 mm, and 21% had one less than 5 mm. Of particular note, a surprising percentage of these patients in the study were asymptomatic. Had they moved forward with cataract surgery prior to the treatment of their dry eyes, they may have come away with a very different outcome in three areas: visually, comfort, and the risk of complications. In order for the proper IOL calculations, biometry measurements are taken including keratometry, topography, wafer imaging, and lens power profiles. With a poor precorneal tearfilm, there can be a large irregularity in these measurements. The refractive changes from air to the precorneal tear film is the largest index shift throughout the entire optical system and therefore, can play a huge role in the lens calculations. There have been a number of cases published showing IOL calculations before and after aggressive treatment of patients with dry eye using preservative-free artificial tears and Cyclosporine. In certain circumstances, these values changed by up to 1.00 diopter of sphere and 1.50 diopters cylinder. This helps explain that awkward conversation after cataract surgery when the visual outcome is not as good as you predicted, or the difficult conversation with the patient that just spent a pretty penny on their premium IOL. Next, studies show that eyes get more dry after cataract surgery. What this means is that our dry eye patients get drier, and our previous non dry eye patients become a dry eye patient, at least for a while. Objective measurements have shown significant decreasing in the tear break up time and Schirmer’s strip core following surgery. All patients are likely to experience some discomfort after surgery, but the worse their dry eye is before surgery, the worse it will be after sugrery. One study reported blepharitis to be present in a wopping 59% of its patients presenting for cataract surgery. We certainly want to address blepharitis, as it’s the number one risk factor for endophthalmitis after cataract surgery. The cause of dry eye in 86% of patients is meibomian gland dysfunction, and it has been shown to increase the risk of postoperative complications, like corneal ulcers and infections. Finally, anytime the eyes homeostasis is disrupted, we get an increase in inflammation. In addition to making a dry eye drier, inflammation decreases healing potential and causes greater irritation. That’s the cycle – the more dry you are, the worst inflammation you’ll get, and the more inflammation you have , the worse the dry eye you’ll get. Treatment is simple, but always complicated in reality. Fix the dry eye, treat the MGD, decrease the blepharitis as much as you can. In short, do a full dry eye work up on all pre-cataract surgery exams. Put them on Cyclosporine as soon as possible and ensure that the meibomian glands are flowing well with the use of the MGE and utilize therapeutics and lid scrubs to treat blepharitis. We refer you to our previous Clinical Insights for a more detailed description of these treatments. To conclude, we can do a lot on the front end to maximize visual outcomes, comfort, and the risk of complications. Doing so will improve our patients quality of life.

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