Addressing punctal occlusion, tear osmolarity correlation

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Patients with elevated tear osmolarity who underwent punctal occlusion showed rapid improvement in tear osmolarity and other features of dry eye disease.

Dr. Pepose

By Cheryl Guttman Krader; Reviewed by Jay S. Pepose, MD, PhD

St. Louis, MO-Results from a prospective pilot study reaffirm the benefit of punctal occlusion as a treatment for dry eye disease and the value of tear osmolarity as a tool for dry eye diagnosis and patient monitoring.

“The results of this study provide additional evidence of the correlation between tear osmolarity and ocular surface health and show that it changes with effective therapy, supporting its use in patient care,” said Jay S. Pepose, MD, PhD, director, Pepose Vision Institute, and professor of clinical ophthalmology, Washington University School of Medicine, St. Louis, MO.

Evidence of correlation

The study included 20 eyes of 15 patients with baseline tear osmolarity >308 mOsm/L as measured with a point-of-care osmometer (TearLab). They underwent punctal occlusion using sterile pre-loaded silicone punctal plugs (Parasol, Odyssey Medical) and were evaluated after 1 week and 1 month for changes in tear osmolarity, symptoms, corneal and conjunctival fluorescein staining, and tear break-up time (TBUT). Five patients had punctal plugs placed in both eyes and 10 had unilateral treatment.

The results showed statistically significant improvements in all endpoints at both follow-up visits. Mean osmolarity at baseline was 320.4 mOsm/L, had normalized by 1 week to 308.3 mOsm/L, and was 309.8 mOsm/L at 1 month. Mean intereye osmolarity difference also decreased with treatment from 17.3 mOsm/L at baseline to 9.5 mOsm/L at 1 week and 9.7 mOsm/L at 1 month.

Correlation analyses showed a good correlation between the baseline to 1-month changes in osmolarity and ocular staining (Pearson correlation coefficient = 0.6), but a lower correlation between change in osmolarity and change in TBUT and symptom frequency.

“Tear osmolarity is really the gold standard diagnostic test for dry eye disease because it correlates better with disease severity than other signs and symptoms,” Dr. Pepose said. “That is not surprising considering that tear osmolarity is a tightly regulated parameter in patients without dry eye. As dryness becomes more severe, patients lose the homeostatic mechanisms necessary to regulate tear osmolarity and the values increase, as does the intereye variation in osmolarity.

It is important to realize that all of the signs of dry eye disease vary with increasing severity and, in fact, tear osmolarity exhibits less fluctuation than other tests used to assess dry eye, according to Dr. Pepose.

“Tear osmolarity provides a global index for dry eye disease severity and it increases whether dry eye is related to aqueous deficiency, evaporative disease, or both,” he said.

Implications in patient care

Dr. Pepose observed that the lower correlation between change in tear osmolarity and symptoms found in the study is worthwhile considering for its implications in patient care. He explained that when using tear osmolarity to follow patients being treated with dry eye, clinicians may document an improvement in tear osmolarity prior to onset of symptom relief.

“Patients may fail to adhere to treatment if they are not feeling better,” he said. “Being able to show them objective evidence of a treatment benefit has value for encouraging them to continue treatment, and symptomatic relief generally follows.”

Dr. Pepose also noted that the benefits associated with punctal occlusion in this patient cohort are consistent with results of previous retrospective studies, including a trial reported by Jeff Gilbard, MD, and colleagues that also documented a decrease in tear osmolarity using laboratory methods generally reserved as a research tool [CLAO J. 1999;15:216-218].

“Our study shows once again that punctal occlusion works as a treatment for dry eye,” Dr. Pepose said. “It is a simple procedure that improves tear osmolarity, TBUT, and symptoms, and it seems to work pretty quickly, which is an advantage compared with other options, such as topical cyclosporine.”

Jay S. Pepose, MD, PhD

E: jpepose@peposevision.com

Dr. Pepose is a consultant to Allergan, Bausch +Lomb, Mimetogen, and TearLab.