How do eyedrops work?

As I sat in the porch watching the birds jump from one tree to another, momentarily my eyes wandered to the two people in the orchard under the trees. Something was clearly amiss. Dave was looking puzzled. “Young man what is the matter?” I asked.

“Sir, I have been watching grandma instill eye drops in her eyes every day and I am perplexed because as she puts in one drop several drops flow out of her eyes almost immediately. It would appear that the drops are washed out by tears.

“I cannot therefore understand how the eye drops would be effective when they don’t stay in her eyes? I have tried some of the drops in my eyes too. They sting; my eyes become red instantaneously and 10 times more water flow out than I had put. It’s like I had onions in my eyes. I wonder how grandma can go through all these, day in and day out. Do these drops really work?

“Dave, I will first of all answer your last question and later take you up on the others. Your memory is rather short! I can’t believe you can forget what you went through in your early childhood! Do you remember those awful days of severe itching; days when you couldn’t open your eyes on waking up in the morning and you would scream and make all of us run to your bedside?

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Eye drops came to your rescue. At first, it was hell getting the drops into your eyes; you would shut your eyes tightly, wriggle and struggle with your mum and dad before they could get the drops in. After a few days, as young as you were then, you could yourself appreciate the benefits of the drops and often reminded your parents to instill the drops without whenever they forgot. Many a times you had attempted to put the drops in by yourself. How can you now doubt the efficacy of the drops? You had practical experience!

“The aim is to have the eye drop land anywhere in the conjunctival sac or on the eyeball itself. The conjunctival sac is the space between the eyelids and the eyeball. Once the drop is in, it is essential to gently close your eye without squeezing the lids for at least two minutes after.

“This simple action traps the drop in the sac and prevents its loss. Don’t blink! Just shut your lids lightly. Blinking pumps the eye drop medication from the eye surface toward the opening of the tear ducts and out of the eye. Once the lids are shut, the medication will spread across the eyeball’s surface, and within a few minutes, will penetrate the cornea to reach the interior of the eye.

“How may drops do I need to put in the eye for good effect?,” I have been asked. “You need only one eye drop of medication for one dose. Don’t worry if you accidentally apply several drops: it may harm your pocket (because you may have to buy more) but in many cases it won’t harm your eye.

“If you think the drop missed your eye, it’s okay to apply another drop. If you have to use more than one type of eye drop medication, allow a minimum of three minutes between each type of medication.

“And now to your first question – how do eye drops work? All eye drops contain some medications intended to perform some functions. Some eye drops contain antibiotics which kill bacteria on the surface or inside the eyeball. If the intended germs are on the surface of the conjunctiva, the eye drop medication will act superficially and it will not be necessary for it to reach any high concentration inside the eye.

“On the other hand to kill the bacteria within the eyeball, the medication must enter and reach a high concentration within the eye. Some others eye medications reduce intraocular pressure and are used in the treatment of glaucoma.

“When Dave was young, he suffered from allergy and had to use eye drop medication that reduced the effects of allergy such as itching, redness of the eyes and stickiness. There are eye drops containing fluids almost like natural tears for lubricating the eye without causing blurring of vision.”

Just when I thought I had satisfied Dave’s thirst for knowledge he asked again, “Doctor, why do eye drops sting?” I looked at my wristwatch; I was already late for an important meeting. “Dave, I promise I will talk about this when next we meet.”

Apology – Owing to some challenges, the article on THE REAL SECRETS OF AJIDEWE will come out later.