Experience: monocular SE hyperopic defocus and myopia progression

My myopia went worse by 0.25 D in 2 months. Astigmatism is increased after wearing / reading at SE. The reason is, the most probably, hyperopic defocus from spherical equivalent distance or so-called “SE without half” strategy for higher than 1 astigmatism.

I didn’t use any accommodation while reading at SE distance using right eye (11 cm from screen or book). The results: astigmatism went up another 0.5 D. With left eye worsened by 0.25 D, as seen in my post Hoya AR-580: 28.11.2019 vs 24.07.2020

The conclusion. From my understanding, right horizontal EOMs are mostly in isometric contraction, so they can’t relax because any kind of anti-force is lacking (astigmatism is high already, so vertical muscles are stuck in relaxed mode, unlike horizontal that stuck in contraction). Oblique muscles seem to activate with hyperopic defocus (even when you don’t/can’t use ciliary muscle to lift out hyperopic defocus), because I feel something is tensed up deeply around my eyes while viewing something with too strong lenses or too close and refusing to accommodate. The next feeling is slight pain (like soft needles touch my eyes), exactly the same pain, when I was child and experienced sudden decrease in far point of clear vision. Perhaps, that is increase in IOP.

In tissue and muscle relations, opposite effect seem to be equal: tight oblique muscles cause longer eyeball, and longer eyeball causes tight oblique muscles (look, when you flex your arm, your biceps contracts, or you may contract your biceps and your arm will flex).

Some study finds a decrease in inferior oblique muscle fibers diameter in almost every case of high axial myopia. As I may predict, it tries to contract very often but for very short time (predominant isotonic contraction), like tremor.

So, use SE with caution when you don’t have Active Focus. At least, use it on one eye, while giving the other full correction, like I decided to do for now.

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What is SE?

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Spherical Equivalent