DRIPPING THE EYE DROPS
Pull the lower eyelid downwards and drip one to two drops into the lower transient furrow. The patient should keep the eyes closed for a minute or two in order that the blinking does not wash away the medication. One should avoid dripping into the cornea because it causes discomfort.
Ointments have a longer effect than eye drops but they blur the vision and it is more difficult for patients to use them. They are most suitable for use at bedtime and when the eye is covered because that way they retain longer in the conjunctival sac.
Application of ointment: grasp the lower eyelid with two fingers and move it away from the eyeball, then extract 5 mm of ointment into the lower transient furrow.
If it is necessary to cover the injured or inflamed eye, then the patient should be recommend to cover both eyes and rest in a dark room. Covering only the injured eye is less efficient, because moving the pupil and muscles of the healthy eye induces the same movement at the covered eye.
Warm compresses are used for treating infections. Cold compresses are used after trauma or surgery of the eye, and at swelling of the eye adnexa. As compresses, most suitable are tupfers for eye occlusion dipped into warm/cold water.
Routine examinations are not taken at conjunctivitis. It is necessary to take a swab at severe eye infections, some types of corneal ulcers, and at suspicion of fungal infection. The sample should be submitted to the microbiological laboratory as soon as possible.
ANTIBIOTIC EYE DROPS AND OINTMENTS
The first choice at conjunctivitis is an antibiotic in the form of eye drops or ointment. On the market there can be found preparations of sulfacetamide, chloramphenicol, tobramycin, gentamicin, and the combination of neomycin + bacitracin + polymyxin. Caution: neomycin can be an allergen, especially after prolonged use.
At conjunctivitis, antibiotic drops are applied each hour during a day, and
every 2-3 hours during every day over the next few days. Prolonged local use of antibiotics can cause irritating or chemical conjunctivitis.
They are given orally or parenterally, and only for severe infections: gonorrhoic ophthalmia, endophthalmitis, orbital cellulitis, dacryocystitis, cavernous sinus thrombosis, and specific infections (trachoma, tuberculosis), perforative injuries, and at the anterior or posterior uveitis of unknown etiology (effect on the hidden focus).
STEROID EYE DROPS AND OINTMENT
It is usually a combination of steroids and antibiotics and rarely steroids alone. They are applied at noninfectious inflammations of the anterior segment (allergic conjunctivitis, iridocyclitis, and some types of keratitis). It is often forgotten that steroids inhibit corneal epithelization and reduce the natural defenses of the eye. The use of steroids at erosion will worsen it, and at herpes and fungal keratitis it can cause cornea perforation. Prolonged local application of steroids can cause cataracts and glaucoma.
They are applied locally as ancillary therapy at endogenous infection (iridocyclitis), especially if the steroids mustn’t be given due to the corneal damage. At endogenous infections with rheumatic background they are given orally.
In Croatia, tetracaine is used almost exclusively and only in medical diagnosis and at local surgical procedures. It must never be used therapeutically for relieving the pain because it prevents healing of the cornea and it is toxic for its epithelium. For reducing ocular disorders and relieving the pain caused by corneal damage, analgesics are applied systemically.
They contain polyvinyl alcohol or methyl cellulose. There are a lot of similar products on the market. Products without preservative are better because preservative is often an allergen and it irritates the eye. Artificial tears are suitable for prolonged use at dry eye or as a help with wearing contact lenses.
They usually contain phenylephrine, naphazoline, tetryzolin or similar vasoconstrictor substances. Sometimes they are combined with antihistamines. Occasional use is harmless, but patients often use them on their own initiative and for a long time, which causes irritation and reactive hyperemia.
CYCLOPLEGICS AND MYDRIATICS
Mydriatics cause pupil dilation, which is similar to cycloplegics. It should be borne in mind that brown irises require stronger mydriatic than the bright ones.
Cycloplegics cause paralysis of the ciliary muscle and mydriasis, required in skiascopy and posterior segment examination. Patients should be warned that these eye drops blur vision at close range for several hours, and that brighter light will bother them due to wide pupil. All cycloplegics and mydriatics start reacting within 15-60 minutes, but they differ in the duration of the effect. Tropicamide 1% is used most often. It should be dripped twice in 5 minutes. Mydriasis occurs within 20 minutes and lasts for about four hours.
Cyclopentolate 1% is stronger and lasts for about 24 hours.
Homatropin 1-2% works for about two days.
Atropine 1% is the strongest cycloplegic and lasts up to seven days.
Phenylephrine hydrochloride 10% is a mydriatic without a cycloplegic component.
Timolol 0.25% and 0.5% (Timalen ®, Metablen ®) helps treat glaucoma of the open angle. It reduces the secretion of the aqueous chamber for about 20%. It is contraindicated in asthmatics.
Pilocarpine 1%, 2% and 4% cause miosis and enhance aqueous humor drainage. It should be given 1-6 times a day. The preparation in gel form (Pilogel ®) should be given once a day, in the evening. It has the same effect as dripping drops every 4-6 hours.
CARBONIC ANHYDRASE INHIBITORS
1) Acetazolamide (Diamox ® tbl) is an oral carbonic anhydrase inhibitor and it reduces production of aqueous humor for about 30%. It has a systemic effect and numerous side effects, especially at older people: paresthesia, confusion, increased risk of kidney stones, etc.
2) Dorzolamid (Trusopt ®) is a topical carbonic anhydrase inhibitor, almost as effective as oral inhibitors, but with far fewer side effects.
1) Latanoprost (Xalatan ®) is a prostaglandin analog which increases uveoscleral drainage of aqueous humor. It is a new product that provides much hope when it comes to glaucoma resistant to other medication and glaucoma with night blood pressure increase. It may cause the iris hyperpigmentation, hypertrichosis of eyelashes and uveitis.
Acyclovir (Aclovir ®, Zovirax ®, Virolex ®) in the form of ointment (rarely as tablets) is used for herpes simplex keratitis.
Newer antiviral drugs – ganciclovir, famcyclovir, trifluorotimidina, idoksiuridin, vidarabine and foscarnet. Among them mostly are used famcyclovir and ganciclovir, which is effective against both types of herpes simplex virus, Epstein-Barr, varicella – zoster virus, cytomegalovirus, and it, can also be applied intravitreally.