Applying an ophthalmic ointment like Sterdex may seem trivial, but poor technique reduces the effectiveness of the treatment and increases the risk of irritation. Sterdex, which combines oxytetracycline and dexamethasone, comes in a single-dose capsule containing an ophthalmic ointment, not a classic liquid eye drop. This distinction changes everything in the technique to be adopted.
Ophthalmic ointment or liquid eye drop: why the technique differs for Sterdex
Have you ever used eye drops? The reflex is to tilt your head and let a drop fall. With Sterdex, the gesture is different. The single-dose capsule contains a semi-solid ointment, thicker than a liquid eye drop.
This greasy texture forms a film on the surface of the eye. This film takes longer to dissolve, prolonging the contact of the medication with the area to be treated. In return, the ointment blurs vision for several minutes after application.
To know precisely how to apply Sterdex as eye drops, you must first understand that the capsule opens by twisting and that the contents are deposited in the lower conjunctival sac, not directly on the cornea.
Specifically, this means that you do not count drops. You gently squeeze the capsule to deposit a small ribbon of ointment under the lower eyelid. One single-dose capsule is enough for one eye, and the rest cannot be stored after opening.
Preparation before applying Sterdex: hands, capsule, positioning
Washing your hands sets the stage for everything that follows. Dirty fingers can introduce bacteria into an eye already weakened by infection or inflammation. Use soap, rinse thoroughly, and then dry with a clean towel.
Then check the single-dose capsule before opening it:
- Check the expiration date printed on the packaging, especially if the Sterdex comes from your home pharmacy and not from a recent dispensing.
- Visually inspect the capsule: it should show no leaks or deformation.
- Prepare a magnifying mirror and sit comfortably, with your head slightly tilted back.
Never touch the tip of the capsule with your fingers or eyelashes. This simple reflex prevents contamination of the contents and protects the eye from superinfection.
Application gesture of Sterdex in the conjunctival sac
The conjunctival sac is the small pocket that forms when you gently pull the lower eyelid down. This is where the medication should land.
Open the capsule and deposit the ointment
Hold the capsule between your thumb and index finger. Twist the end to open it. With the other hand, lower the lower eyelid by placing a finger just below the lash line.
Look upwards. Squeeze the capsule to deposit a thin ribbon of ointment in the conjunctival pouch. Avoid squeezing too hard: an excess of ointment overflows and blurs vision without improving effectiveness.
Close the eye and distribute the product
Release the eyelid, then gently close the eye for thirty seconds to a minute. This contact time allows the ointment to spread over the cornea and conjunctiva.
Gently press with your finger on the inner corner of the eye (near the nose). This gesture, called lacrimal point occlusion, limits the passage of the medication into the nasal passages and reduces the systemic absorption of dexamethasone. This precaution is particularly important for prolonged treatments.
Order of application when Sterdex accompanies other ocular treatments
A doctor sometimes prescribes a liquid eye drop in addition to Sterdex. In this case, the order of application is not trivial.
The liquid eye drop is always instilled before the ophthalmic ointment. The reason is mechanical: the greasy film of the ointment forms a barrier that prevents the subsequently instilled drops from penetrating properly. Reversing the order decreases the absorption of the eye drop.
The interval between the two dosage forms also deserves attention. A few minutes between two different liquid eye drops is generally sufficient, but between a drop and an ointment like Sterdex, a longer interval is recommended to avoid the second product “washing out” the first.
Common mistakes that reduce the effectiveness of ophthalmic treatment
Some habits seem logical but harm the treatment:
- Reusing an opened single-dose capsule: the Sterdex single-dose does not contain a preservative. An opened capsule exposed to air becomes a breeding ground for bacteria.
- Applying Sterdex just before driving: the ointment blurs vision for several minutes. Plan to apply it in the evening at bedtime or at a time without immediate visual need.
- Using the same capsule for both eyes in the case of unilateral infection: one bottle or capsule per eye reduces the risk of cross-contamination.
- Touching the tip of the capsule with the eyelid or eyelashes, which transfers germs into the container.
Supply tensions and management of single doses
The ANSM has reported supply tensions on certain eye drops in France. This situation encourages not to waste single doses. Applying Sterdex correctly the first time avoids having to start over and losing a capsule. If the ointment has properly reached the conjunctival sac, a second application does not provide any additional benefit.
Treatment with Sterdex remains a regulated medical act. The duration and frequency of application depend on the doctor’s prescription. Changing the rhythm, even to “save” single doses, can compromise healing or promote bacterial resistance to oxytetracycline. In case of doubt about the technique or dosage, the pharmacist remains the first accessible contact without an appointment.
