In this installment of Dry Eye Fireside Chat, Damon Dierker, OD, FAAO, sits down with Bennett Walton, MD, MBA, to discuss how optometrists can address dry eye in pre-surgical patients to optimize surgical outcomes.
Dr. Walton is a fellowship-trained cataract and refractive surgeon who practices at Bennett Walton Vision in Houston, TX.
Managing dry eye in pre-surgical patients
A startlingly high percentage of cataract patients have preexisting ocular surface disease (OSD), noted Dr. Walton. For example, in a study by Gupta et al. of 120 patients presenting for cataract surgery evaluation, 56.7% of patients with cataracts had abnormal tear film osmolarity, and 63.3% had abnormal MMP-9 levels.1
Overall, 80% of patients had at least one abnormal tear test result that suggested ocular surface dysfunction, while 40% of patients had two abnormal results.1 With this in mind, Dr. Walton explained that he tends to encounter two types of pre-surgical patients with OSD: the “90-10” patients and “50-50” patients.
For 90-10 patients, cataracts cause 90% of the decreased vision and OSD contributes another 10% of variability in their vision. In contradistinction, 50-50 patients have OSD that significantly impacts their vision, perhaps as much as the actual cataracts. He added that managing 50-50 patients tends to take longer because there is more vision to be gained through OSD treatment.
Based on Dr. Walton's surgical experience, 90-10 patients make up the vast majority of pre-surgical patients, and for the most part require education and potentially eye drops as well as a mild corticosteroid to manage their symptoms. Then, he repeats measurements after a few weeks of treatment and averages the two values.
Examples of managing OSD in pre-surgical patients
Dr. Walton recounted how a patient with central epithelial basement membrane dystrophy (EBMD) was referred to him for cataract surgery. Due to the location and severity of the EBMD, he performed a corneal smoothing procedure, and following that intervention, the patient gained enough visual improvement that she was happy and will reevaluate cataract surgery in the future.
Another patient was sent in for a clear lens exchange (CLE) custom lens replacement and wanted to replicate the monovision she used to enjoy with her contact lenses. However, she had secondary contact lens intolerance due to underlying dry eye disease. Accordingly, Dr. Walton prescribed a course of serum tears for 6 weeks, and the patient made significant progress; she gained two lines of best-corrected visual acuity (BCVA) in one eye and one line in the other.
Now, they are planning on implanting a light adjustable lens (LAL) because this patient also has non-central EBMD—which can reduce the accuracy of the measurements for cataract surgery. However, with a LAL, modifications can be made after the procedure and the vision can be tailored to feedback from the patient.
DED diagnostic tools for refractive and cataract surgery patients
Dr. Walton's two favorite pre-operative tests to identify dry eye in refractive and cataract surgery patients are placido disc imaging and optical biometry. He added that placido disk imaging can be helpful for patient education, as it is easy to see and understand that the non-concentric mires indicate the presence of corneal irregularities.
To perform optical biometry, Dr. Walton's practice utilizes an IOLMaster 700 (ZEISS), which displays corneal reflection quality indicators in a technician-friendly way. This device utilizes partial coherence interferometry—meaning that it measures the signal produced as a result of the interference between the light reflected by the tear film and the light reflected by the retinal pigment epithelium (RPE).2
Dr. Walton noted that the treatment goal for a large portion of his cataract surgery patients is to regain driving safety as soon as possible. Consequently, for many patients, rather than using long courses of slower-acting eye therapies, the easiest answer that will permit them to achieve this goal is to prescribe a course of topical lubrication along with a mild corticosteroid.
This blanket treatment tends to work reliably in mild cases, but it is important to keep in mind that ocular surface maintenance after the procedure is equally important, because patients are unlikely to preserve the visual stability and improvements in ocular surface health after they discontinue the drops.
When treating "50-50" patients, he assesses signs, symptoms, and quality of vision, and whenever these values begin to plateau on a therapy, he knows that the patient has maxed out the therapeutic benefit. At that point, he reevaluates what the patient needs to get them closer to surgery.
Conclusion
Overall, treating dry eye and OSD in pre-surgical patients requires six key elements:
- Identifying the patient’s treatment goals
- Comprehensive patient communication on OSD and cataract surgery
- Classifying patients as being either “90-10” or “50-50”
- Utilizing and repeating diagnostics, such as placido disc imaging and optical biometry
- Initiating OSD treatments quickly to get patients to surgery
- Continuing OSD treatments after surgery to maintain the health of the ocular surface
