Eye drops and eye ointments are generally instilled into the pocket formed by gently pulling down the lower eyelid and keeping the eye closed for as long as possible after application, preferably 1-2 minutes; one drop is all that is needed so long as instillation is successful. A small amount of eye ointment is applied similarly; the ointment melts rapidly and blinking helps to spread it. Generally it is inadvisable for patients to continue to wear contact lenses, particularly hydrophilic (soft) contact lenses when receiving eye drops.

When two or more different eye-drop preparations are used at the same time of day, or ointment at the same time as drops, the patient should leave an interval of 5 minutes between preparations to avoid dilution and overflow.

Please remember that, once opened, most eye drops have to be discarded after 28 days. If there is a choice of pack size (e.g. 5 or 10ml) please prescribe the size most appropriate for the length of treatment to avoid waste.

Single use and unpreserved eye drops should be reserved for patients with chronic known allergy to preservatives and/or for diagnostic purposes only.

Certain preparations included within this formulary are unlicensed. These products will be ordered specially and are not stocked; therefore a delay in obtaining stocks may be incurred. These 'specials' may be supplied when clinical need for the individual patient demands, given no commercial alternative is available. Specials are often very costly. These 'specials' are usually preservative free so please be aware of the advice below.

Administration aids

Eye drop dispensers are available to aid the instillation of eye drops especially amongst the elderly, visually impaired, arthritic, or otherwise physically limited patients; they may be useful in children in whom normal application is difficult. Eye drop dispensers are for use with plastic eye drop bottles, for repeated use by individual patients.

Occasionally patients may need an administration aid which is only compatible with the branded preparation of the drug. If this is the case, ophthalmologists should clearly state in correspondence that the patient has dexterity problems and needs the assistance of such a device, and therefore requires the brand preparation to be prescribed.

Opticare

• Eye drop dispenser for 2.5-20mL bottles (£4.95)

Opticare Arthro 5

• Eye drop dispenser for 2.5-5mL bottles (£4.95)

Opticare Arthro 10

• Eye drop dispenser for 2.5-20mL bottles (£4.95)

The Opticare devices may be prescribed on FP10 and fit the majority of bottles. Notable exceptions being Timoptol LA for which an aid is available from MSD, and Xalatan for which community pharmacists may obtain a device from Pfizer (01737 330000). It can accommodate Travatan and Duotrav but a special device is available from Alcon (08000 924567) free of charge. To use Opticare with the MSD products Trusopt, Cosopt, and Timoptol the bottle must be inserted flat side first with the lid removed.

Compatibilities with these products can be checked with the manufacturer on 01484 667822 or at the Cameron-Graham website.

Preservatives and sensitisers

Many eye preparations contain a preservative e.g. benzalkonium chloride. Long-term administration of preservative containing eye drops may cause ocular irritation. Patients sensitive to preservative usually develop the allergy after chronic use.

The following recommendations are for when to use preservative free treatments:

• the patient has an allergy to the preservative
• frequent use of the drops – six or more times a day (long-term use)
• the patient is wearing a soft contact lens or bandage lens at the time of instillation, on specialist advice
• after a corneal transplant in selected cases, depending on indication, and in cases where the cornea is compromised, on specialist advice
• ocular surface disease, including severe dry eye syndrome

Some patients using preservative-free eye drops in multiple-use containers could be at risk of serious eye infection due to microbial contamination of the product. Doctors should exercise caution when prescribing multiple-use eye drops without preservative in patients at high risk of infection.