By Ernie Bowling, OD, MS, FAAO, Dipl.
Posted on May 23, 2013
Dry eye syndrome (DES) is a frequently encountered problem in any eye care practice. The management of severe dry eyes is a continual challenge to clinicians. Most current available treatments are limited to providing relief from symptoms. In essence, two approaches are used: constant lubrication and conservation of the patient’s existing tears. In patients who do not find symptomatic relief despite medical therapy and maximal lubrication, punctal occlusion is often indicated [AAO 1997]. Next to medical therapy, blockage of the lacrimal drainage system is the most common form of treating dry eye. Rather than applying an artificial tear, punctual occlusion helps to preserve any remaining natural tear fluid, which has by far the best wetting and nutrient capacity for the ocular surface. Preserving the patient’s own natural tears by blocking the lacrimal drainage system, thereby increasing tear volume and decreasing tear osmolarity can successfully maintain the integrity of the ocular surface, corneal transparency and visual acuity. In patients with moderate or severe dry eye, it is capable of improving quality of life and preventing vision loss.
Punctal plugs were first reported as a reversible, effective, and physiologic treatment for a variety of dry eye disorders by Freeman in 1975 [Freeman 1975]. The idea behind punctal occlusion is straightforward: increase the aqueous component of the tear film by blocking tear outflow [Dohlman 1978]. Explaining the procedure to patients, one can compare it to blocking the drain in a sink and collecting the water dripping from the tap. Punctal occlusion helps to retain the patient’s own tears on the ocular surface. This intervention is highly effective and usually used after environmental control, drop therapy, omega-3 fatty acid supplementation and topical Restasis prove inadequate. Preferably performed after surface inflammation is brought under control, occlusion methods include punctal plugs as well as thermocautery, electrocautery, laser ablation or direct surgical closure [AAO 1997].
Before performing a procedure to occlude a punctum permanently, many authors suggest a trial of temporary punctal occlusion using various plugs [Cohen 1999]. While this is prudent, one must keep in mind some of the intrinsic limitations of these devices. More specifically, Glatt noted failure of collagen plugs to predict epiphora after permanent punctal occlusion [Glatt 1992]. Redmond also pointed out some of the intrinsic limitations of these devices in making these predictions [Redmond 1992]. One systematic review [Ervin 2010] showed a relative scarcity of controlled clinical trials assessing the efficacy of punctal occlusion therapy in dry eye. Although the evidence is very limited, the data suggest that silicone plugs can provide symptomatic relief in severe dry eye. Moreover, temporary collagen plugs appear similarly effective to silicone plugs on a short-term basis. While Geldis and Nichols [Geldis 2008] found no impact of punctal occlusion in symptomatic dry eye contact lens wearers, indicating either the treatment effect while present was not detected, or punctal occlusion had no treatment effect at all, the results of another study [Nava-Castaneda 2003], which randomly assigned patients to active or sham treatment, clearly demonstrated some of the clinical benefits of lacrimal occlusion in patients with dry eye of mostly mild to moderate severity. Individual and total symptom scores markedly declined for the occluded patients over an 8-week progressive treatment/follow-up period, in association with a reduction in artificial tear use and corneal/conjunctival fluorescein staining, as well as improvement in best-corrected visual acuity and ocular comfort/visual performance. The magnitude of the treatment effect was more striking following implantation of non-dissolvable silicone plugs, but occlusion with temporary collagen plugs also had an apparent beneficial influence on the clinical course of dry eye, as indicated by significantly lower scores for several study parameters in comparison with the control group.
Punctal Occlusion and Inflammation
One area of interest is the relationship of pharmacologic therapies with punctal occlusion [Yazdani 2001]. Published practice patterns call for punctal occlusion in severe cases after traditional aqueous enhancement has failed [AAO 2003]. Punctal occlusion has been shown to improve objective and subjective measures of dry eye [Dursun 2003] but may exacerbate ocular surface inflammation in subjects with overt clinical inflammation [Pflugfelder 2004]. Because of this issue, an international panel of experts developing comprehensive treatment guidelines for ocular surface disorders recommended that the inflammatory condition be treated before punctal occlusion [Behrens 2006]. In a prospective, randomized clinical trial by Maite Sainz de la Maza, M.D., Ph.D., and colleagues [Sainz 2000], topical treatment of dry eye patients with non-preserved methylprednisolone and punctual plugs significantly decreased the severity of ocular irritation symptoms and corneal fluorescein staining, compared to the group that received punctual occlusion alone.
Punctal Occlusion in Other Ocular Diseases
Although punctual occlusion is specifically indicated in aqueous-deficient dry eyes, other types of dry eye or corneal surface diseases may also be improved with punctal occlusion [Yang 1997]. Punctal occlusion can be beneficial for patients with aqueous tear deficiencies secondary to other ocular surface conditions. Ocular cicatricial pemphigoid is a disease affecting, among other structures, the mucin-producing goblet cells of the conjunctiva, and it can also be associated with severe cases of dry eyes. Patients with pemphigoid and dry eyes may benefit from punctal occlusion in addition to systemic therapy of their disease. Neurotrophic keratitis of any cause can be associated with dry eyes because of reduced reflex tearing, and the ocular surface improves dramatically following punctal occlusion in some cases. Punctal occlusion may also be beneficial in patients who have dry eyes caused by increased evaporation from a more exposed ocular surface following blepharoplasties or in cases of lagophthtalmos. Punctal occlusion has also been reported to be effective in reducing the incidence of dry eyes associated with superior limbic keratoconjunctivitis [Yang 1997]. Complications
Although punctal occlusion is an effective therapy for KCS, there are complications related to punctal plug insertions [Sugita 2001]. Recognized complications of conventional silicone plugs include epiphora, punctal ring rupture, abrasion of the corneal and conjunctival surface, and suppurative canaliculitis [Muribe, 1996]. Although the retention rates for the different kind of silicone plugs have been reported to be about 50% after 1 year [Kojima 2002], extrusion of silicone plugs is common, occurring within 3 months in up to 50% of cases [Balaram 2001;131:30-36].
Careful patient selection is critical for successful punctal occlusion. It should be performed only when appropriate, and when the likelihood of benefit far outweighs the risk and cost. A variety of techniques are available to choose from on the basis of the duration of desired effect and the severity of aqueous tear deficiency and associated ocular surface disease. Punctal occlusion can dramatically improve the quality of life in many patients with moderate cases of dry eyes and can prevent visual loss in patients with severe cases of dry eyes.