Which class of glaucoma medication is MOST likely to lead to a myopic shift?

The class of glaucoma medication that is most likely to lead to a myopic shift is carbonic anhydrase inhibitors. These medications work by decreasing the production of aqueous humor in the eye, which can lead to a reduction in intraocular pressure (IOP). An interesting side effect of these medications is that they cause a decrease in the pH of the aqueous humor, leading to a transient increase in the eye's refractive index. This change can result in a myopic (nearsighted) shift in the patient's vision.

Carbonic anhydrase inhibitors, such as acetazolamide, often lead to this refractive change because the altered fluid dynamics and osmotic changes can affect the optics of the eye. As the eye's shape or the anterior and posterior chamber depth may change mid-treatment, the patient's refractive error can shift toward myopia.

Other classes of medications—such as prostaglandin analogs, alpha 2 agonists, and beta blockers—do not typically produce a significant change in refractive status such as a myopic shift. Prostaglandin analogs mainly increase uveoscleral outflow, which facilitates the drainage of aqueous humor without affecting the eye's refractive properties. Alpha 2 agonists