research in practice

Plug Up Glaucoma Progression

A recent study shows punctal occlusion can significantly reduce IOP.

Mile Brujic, O.D., Crystal Brimer, O.D.

We have all thought, at least anecdotally, that because punctal occlusion inhibits the immediate outflow of the tears and confines fluid to the ocular surface for long periods, it could possibly play a role in enhancing the effectiveness of topical medications.

Despite the impressive efficacy of prostaglandin analogues (PGA), many patients still must achieve a lower IOP measurement. In fact, studies have revealed that 28% to 40% of patients who began with PGA monotherapy required additional glaucoma treatment.^1,2 Yet, any adjunctive therapy, including a second drop, laser procedure or surgery, can have a negative effect on patient cost and compliance, cause side effects and hurt one's quality of life. Recently, however, researchers have shown that silicone punctal plugs can be effectively used as an adjunctive therapy to patients using a PGA alone.³

The supporting research

Very few studies include data on the effect of punctal occlusion on IOP reduction in patients using glaucoma medication: In a study published in 1989, researchers plugged the lower puncta of one eye in 19 patients who were using various glaucoma treatments.⁴ The results: A mean decrease in IOP of 1.32mmHg compared with the fellow unplugged eye and a decrease of 1.82mmHg compared with the same eye before punctal occlusion.

In a study published in 1996, researchers tested the effect of punctal occlusion on IOP reduction on 20 patients and found a mean decrease of 2.00mmHg post-punctual occlusion when compared with the same eye before occlusion.⁵ In another 1996 published study, researchers compared the effect of timolol maleate 0.25% (Timoptic, Valeant Ophthalmics) in 17 patients who had their lower puncta occluded with silicone plugs vs. its effect in the same patients without punctal occlusion following a two-week wash-out period. The results: No statistically significant difference in IOP with and without punctal occlusion was noted.⁶ Of note: None of the aforementioned studies included a PGA.

In a study published in 2011, researchers studied 13 patients already compliant with travoprost 0.004% (Travatan, Alcon) q.d. OU, who had stable IOP measurements for at least one year.3 Silicone punctal plugs were used to occlude both the upper and lower puncta of one eye in each patient, thereby utilizing the same patient as both the control and study.

Applanation tonometry was performed at baseline and again after one month, within two hours of the original measurement.

Data was collected from 11 patients (one patient quit due to epiphoria in the test eye, and the other was excluded due to upper plug loss). The test eyes showed a mean IOP decrease of 1.59mmHg or -6.82%, while the control eyes had a mean IOP increase of 0.14mmHg or +1.91%. On average, the difference between the two eyes was 8.74% (1.73mmHg). This reduction is statistically as well as clinically significant.

What this means for patients

Studies have substantiated the profound effect that even a 1mmHg change in IOP can have on the patient's risk for glaucoma progression; anywhere from 10% to 19%, more recently.^7,8 Therefore, it would be naive to discount the impact that even a small, 1.73mmHg decrease can have on patient care.

Some patients on PGA monotherapy will require a much greater drop in IOP to maintain optic nerve stability. But, punctal occlusion may be an excellent option for those patients in which a more modest reduction can provide the added protection necessary. It may be perfect for those who are just above their target IOP or for patients who have met their goal IOP, but experience mild fluctuations.

Maintaining monotherapy will allow them to avoid additional medication costs, side effects, dosing complexity and patient compliance issues. And, many glaucoma patients will likely experience improved comfort as an added benefit. PGAs are often blamed for redness and discomfort, especially in an aging population already prone to ocular dryness. Occlusion of the upper and lower puncta may dramatically enhance the every-day comfort of even non-complaining patients.

Real world application

Utilizing silicone punctal plugs to enhance the efficacy of PGAs allows some patients to realize the maximum IOP reduction before turning to other adjunctive glaucoma treatments. Be aware that this is a non-FDA approved therapeutic use, but that research has shown that occluding both the upper and lower puncta of each eye maximizes the potential IOP-reducing benefit for patients on PGA treatment. We advise that you closely monitor plug patients for epiphoria, mechanical discomfort and plug loss.

Incorporating punctal plugs to lower IOP, even in a select population of your PGA patients, can have significant financial implications for your practice. Therefore, consult your individual insurance carriers, as they may reimburse 100% of the allowable fee for the first puncta and 50% for all additional puncta occluded on the same day. Of course, it is certainly justifiable to occlude the two lower puncta first, and monitor for adverse effects before plugging the upper puncta or to plug the upper and lower puncta of one eye to compare the IOP measurements between eyes. Many insurance companies may not accept glaucoma as a diagnosis code for punctal occlusion. However, it could still be a billable procedure if there is other medical necessity, or it can be offered to the patient as an out-of-pocket expense.

Many patients will appreciate your willingness to go above and beyond to avoid adding more medications to their treatment plan. Furthermore, they will probably be quite pleased with their potential for enhanced comfort after punctal occlusion. When properly explained, this type of custom tailored patient care could lead to improved patient loyalty and patient referrals. OM

1. Covert D, Robin AL. Adjunctive glaucoma therapy use associated with travoprost, bimatoprost, and latanoprost. Curr Med Res Opin 2006 May;22(5): 971-6.
2. Kass MA, Heuer DK, Higginbotham EJ, et al. The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol. Jun;120(6):701-13
3. Optitz DL, Tung S, Jang US, Park, JJ. Silicone punctal plugs as an adjunctive therapy for open-angle glaucoma and ocular hypertension. Clin Exp Optom. 2011 Sep; 94(5):438-42.
4. Huang TC, Lee DA. Punctal occlusion and topical medications for glaucoma. Am J Ophthalmol 1989; Feb 15;107(2): 151-5.
5. Aritürk N, Oge I, Erkan D, et al. The effects of nasolacrimal canal blockage on topical medications for glaucoma. Acta Ophthalmol Scand. 1996 Aug;74(4):411-3.
6. Bartlett JD, Boan K, Corliss D, Gaddie IB. Efficacy of silicone punctal plug as adjuncts to topical pharmacotherapy of glaucoma — a pilot study. Punctal Plugs in Glaucoma Study Group. J Am Optom Assoc 1996; Nov;67(11):664-8.
7. Heijl A, Leske MC, Bengtsson B, et al. Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. Arch Ophthalmol 2002 Oct;120(10):1268-79.
8. Chauhan BC, Mikelberg FS, Balaszi AG, et al. Canadian Glaucoma Study: 2. risk factors for the progression of open-angle glaucoma. Arch Ophthalmol. 2008; 126(8):1030-6.