Punctal Plugs

How tears drain, and how plugs change it

Tears leave the eye through two small openings, one in each eyelid near the nose, and drain into the nasal cavity, which is why crying gives you a runny nose. In a dry eye, the tears that are produced drain away as fast as ever, so the surface stays under-supplied. A plug in the lower punctum, or in both, keeps the tears on the eye for longer, raising the tear volume without adding anything. For patients with low production the effect is immediate and often striking.

Types of plug

• Dissolving collagen or synthetic plugs, lasting from a few days to a few months, used to test whether plugs will help and after surgery when temporary support is needed
• Silicone punctal plugs, which sit at the opening of the punctum with a small cap visible at the lid margin, last for years, and can be removed at the slit lamp in seconds
• Intracanalicular plugs, placed deeper in the canal where they are invisible; longer lasting, but harder to remove if needed

Most patients start with the lower puncta; the upper puncta are added if more retention is needed.

The procedure

The punctum is measured, a numbing drop is placed, and the plug is inserted with a fine applicator. It takes about two minutes for both eyes and is painless. Most patients notice improved comfort within hours. There is no restriction on activity.

Who they suit, and cautions

Plugs help most in aqueous deficient dry eye, including Sjogren's syndrome. In patients whose tear film is inflamed, anti-inflammatory drops are needed first, because plugs retain inflammatory tears as well as good ones. They are used after LASIK and cataract surgery to support healing. Occasional problems include a plug that falls out, mild irritation from the cap, and, rarely, watering if retention overshoots, in which case the plug is removed. An eye with an active infection is not plugged until it has cleared.