What is eye drops?
Eyewash is an aqueous, medicated or non-medicated preparation that is applied directly to the eye to treat or improve an eye disorder. Instilled in the eye in the form of drops, the eye drops are indicated in the treatment of glaucoma, eye redness, dry eyes, conjunctivitis, allergies and eye infections. Sometimes, the eye drops are also used to dilate the pupil in order to simplify a specific diagnostic test performed at eye level.
Pharmaceutical form
ACTIVE PRINCIPLES
The eye drops appear as an aqueous solution, generally saline, enriched with medicated substances or natural ingredients with a soothing, emollient or anti-redness action. In addition to the functional substances, the eye drops contain some essential ingredients to preserve the product, promote the solubility of the active ingredient in the aqueous solution and adapt the pH of the substance to that of the eye. Clearly, the excipients must be carefully selected to prevent them from interfering with the pharmacological action of the eye drops or any unpleasant side effects such as burning and redness.
PRESCRIPTION
Not all eye drops require medical prescription: based on the active ingredient contained in the pharmacological preparation, the product can be sold with or without a prescription. For example, eye drops intended for the treatment of uveitis or glaucoma can be sold only by prescription; "natural" anti-reddening or dry eye drops are instead considered over-the-counter products.
CONTAINER
The eye drops can be found both in practical single-dose ampoules and in plastic bottles to be used several times. While in the first case it is not necessary to add an antimicrobial to the basic preparation, multidose eye drops need to be enriched with a specific substance capable of preventing the growth and development of germs. The antimicrobial used must be clearly compatible with the excipients and the active ingredient contained in the product. Multidose eye drops generally have a shelf life of 3-4 weeks: one month after opening, the eye drops must be thrown into the appropriate collection of medical waste.
Indications and types of eye drops
There are many types of eye drops, essentially differentiated on the basis of the active ingredient dispersed in the aqueous solution.
The eye drops are indicated in the treatment or treatment of the following disorders:
- Allergic reactions (eg pollen allergies, grass allergies, hypersensitivity to drugs or preservatives, etc.): the most indicated eye drops are those enriched with antihistamine substances. When the allergy is particularly fierce, the doctor can prescribe the patient with eye drops prepared with corticosteroids.
- Allergic, infectious or irritative conjunctivitis (inflammation of the conjunctiva, the membrane that covers the eyeball and the inner layer of the eyelids): in the case of an established ophthalmic infection, the use of antibiotic eye drops is recommended.
- Glaucoma and intraocular pressure changes: given the dangerous nature of the disease, treatment with eye drops or other specific pharmaceutical forms (eg ophthalmic ointments) is essential to prevent vision loss. The eye drops used in the treatment of glaucoma can be enriched with:
- Beta-blockers, to reduce intraocular pressure
- Prostaglandin analogues, to promote the outflow of aqueous humor and decrease intraocular pressure
- Sympathomimetics, able to reduce the pressure inside the eye (these substances mimic the activity of adrenaline and noradrenaline)
- Carbonic anhydrase inhibitors: by inhibiting the formation of aqueous humor, they are able to reduce intraocular pressure
- Reddened eyes: the eye drops recommended to prevent or reduce eye redness are generally isotonic solutions enriched with emollient and refreshing substances.
- Generic ocular inflammations (aseptic inflammatory states, for example following ophthalmological surgery): the most indicated eye drops for the treatment of this disorder are enriched with analgesic and anti-inflammatory active ingredients (NSAIDs)
- Eye dryness: for the improvement of the typical symptoms of ocular xerosis, the recommended eye drops are enriched with humectants and emollients. When dry eye depends on bacterial infections, the doctor can prescribe a local antibiotic treatment, to be applied in the form of eye drops directly on the affected eye.
- Uveitis (generic inflammation involving iris, choroid and ciliary body): eye drops based on cortisone, dexamethasone or prednisolone are the most indicated for treating a type of ocular inflammation which, although associated with uveitis, is of uncertain origin. When a bacterial infection is detected at an ocular level, antibiotic eye drops are undoubtedly the most suitable.
Mode of use
Despite being destined for numerous eye disorders and pathologies, the method of administering the eye drops remains the same. What changes is rather the dosage, that is the frequency of application, the quantity of drops instilled in the eye and the duration of the therapy.
It is not uncommon for a small amount of product to slide down the cheek. This event, which is absolutely normal, should not be a cause for concern: in this case, the quantity of excess solution must simply be dried with the help of a cotton pad or a tissue.
After applying the eye drops to the eye, it is advisable to avoid immediately tightening the eyes: rather, it is preferable to try to close the eyelids gently.
The administration of the eye drops in the child may be more problematic because the small patient tends to get excited. In these cases, it is advisable to lay the child on a medium-soft surface (eg bed) to prevent him from moving too much. During the administration of the eye drops, it is advisable to create a sort of "pond" of eye drops on the inner part of the eye (even if the child keeps his eyes closed): when the baby opens his eyes again, a sufficient amount of drug will inevitably penetrate in the conjunctival fornix.
Warnings
It is first of all important to always seek the advice of your doctor before instilling any type of eye drops in the eye: self-therapy is strongly discouraged since it risks generating unpleasant side effects.
Before instilling the solution, shake the eye drops well.
Once the product is opened, it is a good rule to check the validity of the drug (expiry date): some eye drops, especially those intended for the treatment of eye infections, lose their therapeutic efficacy after 5-7 days from the opening.
Although obvious, it is important to reiterate the importance of strictly adhering to the administration recommended by the doctor. We remember, in fact, that not all eye drops are the same: while some require only a double daily administration, others must be instilled every 3-4 hours. When you change the dosage without first consulting an expert, you risk prolonging the disease.
Note:
- In the presence of contact lenses, medicated eye drops can be instilled into the eye only after they have been removed. Following the application of the eye drops, contact lenses can be reapplied after at least 15 minutes. However, there are some pharmaceutical preparations suitable even for those who wear contact lenses.
- During the instillation of the eye drops, it is recommended to pay particular attention to avoiding the contact of the spout of the container with the eyelashes or, worse still, with the iris or an ocular structure. This foresight is important not only to avoid the risk of trauma or scratches to the eye, but also to minimize the possibility of ocular self-infection if multidose bottles are used. Just think, for example, of the risk of self-contamination in the presence of bacterial uveitis.
- If more than one topical ophthalmic drug is required, it is recommended to administer the eye drops at least 5 minutes apart.
