Discovery about active focus after getting pupil dilation drops

Went to the optometrist yesterday, because I had a pseudo-blind spot appear in my view that turned out to be related to a new cotton wool spot in my right eye. As part of the exam, I got those pupil dilation drops (and an anesthetic right before them). It had been at least 10 years (possibly 15) since I got them last. Got a big clue as to how active focus works, or more specifically, how it does not work.

I’d mentioned my eye improvement process to the optometrist. At the end she had me check my vision, which puzzled me a bit, as I know one’s prescription is much worse with medically dilated pupils vs regular eye exam pupils and lighting. At first she put up a view, and I was unable to clear the view, but the view was obviously too strong (which I complained about). She acquiesced to my complaints and put weaker lenses in, that I had no problem reading. Turned out they were -4.0 (my prescription she determined for me two years earlier were 5.0s). Given that my eyes were fully dilated I suspect my prescription in dark opto office settings is about -3.25D, which aligns well with my personal measurements.

But I digress. What struck me is that I should have been able to clear the line with a diopter or two too strong prescription. I couldn’t I tried. It was close enough to being legible but nothing I did could clear it. Later I did some research, and what did I find? That the drops (or maybe the anesthetic applied before them) inhibits the normal accommodation reflex. In other words, it interfered with the ability to accommodate via the ciliary muscle in the usual way to see close up.

Why do I bring that up? Because before that part of the exam, after my eyes had fully medically dilated, I was playing around and found that I could active focus normally. No problems whatsoever improving the (crummy) view with active focus. I could look at something a bit far with too weak (with the drops) view, then clear it, then relax it back to blur again.

So I realized the next day (today) that that’s a big clue to the active focus mystery (what exactly is it). It’s obvious (to me) that active focus does not involve the ciliary, or anything near the pupil area. My eye muscles in the area were all misbehaving (due to the medication), yet I was able to active focus at will, and to the usual degree.

I have my guesses as to what active focus is (and this experience helps confirm that for me), but do others have some ideas as to why I couldn’t near focus at all with those eye drop drugs, but had no problem with using active focus?

Maybe? :slight_smile:

What was the name (or ingredient) of the drop? Based on the paper linked in that topic there are some which paralyses only the ciliary, but not the trabecular meshwork. If it was such one, that’s another argument for the meshwork doing the af.

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Besides extra ocular muscles doing something no idea. Do enlighten us :grin:

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Dunno the ingredient, will ask next time I’m there.

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I have a newbie question about this…

My son was given pupil dilation drops before his eye exam last week. Does pupil dilation indicate a fully released cilliary?
In other words, does Pseudomyopia actually not show up in dilated pupils?

Can the first differentials still possibly give the initial improvement if the starting prescription was based on an eye exam with pupil dilation?

I think this can be slightly different with different drops. You can safely assume that your son does not have pseudomyopia if his measurements under dilation are the same as pre-dilation.

The EM method works for most forms of myopia, and not only pseudomyopia, so I think you can carry on according to plan. I wonder why he would need diffs with fairly low myopia? He can certainly make use of norms, and practice active focus with them, as well as without any glasses. Were the measurements any different to the ones you have posted before?

Oh he doesn’t use differentials in the sense the others do. You’re right in that he only needs norms. He uses +1.5 though when sitting for an online class on the iPad. (Which I’ve very recently started projecting on the tv so even that is minimized)

His cm measurements were about 65 cm till November and now they are 50cm.
I wonder if that’s elongation or just a cilliary lock up.
Either way I know nothing changes. He needs AF and I need patience.

I know this is a strategy used with children , but have no idea how it works. If his cm distance has deteriorated, it does not seem that this is doing any good. What were the most recent opto measurements in diopters?

You never finished up this conversation…

As far as I know yes. But there’s a problem.

The human eye suffers from what’s known as spherical aberration. It’s what makes some portrait lenses on cameras result in such a nice looking photo, but in our case, it means that the focus of the eye “shifts” the wider the pupil. For example, fully constricted pupils (e.g. bright daytime) can see about 0.25D better than indoors pupils, and 0.75D better than fully dilated (naturally) pupils in dark nighttime skies. It gets worse with medically dilated pupil.

So on the plus side, the drops ensure one can’t “cheat” by accommodation during a test (due to the lens muscles being deactivated), but one also sees potentially a diopter worse than “normal”. This “cheating” is common amongst the young as it’s so easy for them to accommodate, and since mild-to-moderate accommodation actually does make the letters look sharper and clearer (leading to overprescribed lenses. It is not them attempting to “cheat” but by honestly answering that the letters do indeed look sharper with a diopter too-strong lenses, for example).

The eye drops are useful to prevent that, as it disables the child’s eye’s ability to accommodate.

What does this mean, the spherical aberration when the pupil dilates? It means a child tested this way requires the opto to “adjust” the prescription to account for this, otherwise the child will get a prescription that is potentially 0.75 diopters too strong.

So ironically, an attempt to avoid over prescription (due to children’s ability to accommodate well and their tendency to tell you the truth: “it does look better with too-strong glasses”) can lead to over prescription (the fully dilated pupil requiring an extra 0.75 diopters to see best).

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What didn’t do him good was him falling into bad habits through December and January. Initially he made improvements with the + lens. I didn’t even measure his eyes through these months.

If that is the case I still have hope. Because it means some gains associated with the cilliary could be made faster.
His measuremts at the opto before the drops were put were the same as after, so there’s that.
Yesterday we were looking at car license plates and I realised he struggled to read certain numbers with his full prescription even though I could read them clearly.
All in all I don’t know what to make of the prescription.
Frequently Changing the course of action when working with a child isn’t a good idea because then they tend to take nothing seriously :-/