I'm using my simple solution for slightly over a week now, but don't have any measurable effects yet. However, subjectively, I felt my eyesight was more relaxed last days when looking at far objects like trees or clouds. But it seems there might be other problems than presbyopia. I have booked an appointment with an optometrist, but they moved my visit to next week. My near point might be over one meter now... not sure. I'm going to continue with what I have started to simply test it a bit longer.
I've read parts of the original article: https://iovs.arvojou...ticleid=2526363
Interestingly, they used ALA in vitro and as per Figure 4 concentrations {?} from 50µM/L to 500µM/L were effective in the experimental setup. I understand these numbers are solution concentrations, not amounts of the ALA. However:
Then, the medium was replaced with fresh medium supplemented with selected levels of LA (experimental lenses) or with fresh medium (contralateral control lenses). Lipoic acid levels ranged from 1 μM to 500 μM.
This would suggest amount of ALA, not a concentration, and they do not say what was the volume of the bath. I don't like it, frankly, not as tidy as I would like to see it.
But under the Figure 4 in the description they used the word "concentration":
LA concentration (μM)
Anyway, I assume these are concentrations of baths. As ALA solubility in water is 127mg/L, it gives concentration of 615µM/L, even higher than what they have used for lenses in vitro. (Unless I've made some silly mistake in calculations). Still, 50µM number they give was almost as effective as 500µM.
If the above is correct, we can achieve easily these concentrations, but it's unrealistic to provide 12-h exposure in vivo.
OK, why LACE (choline ester of LA)?
Because 50.0 μM to 96.7 μM medium concentrations were needed to significantly increase the elasticity of mouse lenses in culture, four old mice were treated with 5 μL of a formulation of LA, OD. The formulation consisted of LA (0.121 M, 2.8%), tris(hydroxymethyl)aminomethane for increased LA solubility and pH adjustment, as well as 0.1% benzalkonium chloride (BAC). Benzalkonium chloride is not only a biocide, but also a cationic surfactant believed to increase corneal permeability. Forty-five minutes after topical ocular dosing, the aqueous humor LA concentration reached 17.5 ± 5.6 μM, a level well below that needed to affect elasticity. Forty-five minutes after drop application, after euthanasia, the aqueous humor was collected from the treated eye and analyzed by HPLC.
Topical ocular treatment of four old mice with 5 μL 0.119 M (3.4%) formulation of LACE led to LA levels sufficient to effect disulfide reduction and increase elasticity. Forty-five minutes after topical ocular dosing, LA levels in the aqueous humor were 98.2 μM ± 14.8 μm. These levels were 5.6-fold higher than those when the topical ocular treatment was with the 0.121 M (2.8%) LA formulation. Furthermore, the increased levels of LA in the aqueous humor after topical ocular dosing with LACE indicate that ocular esterases hydrolyze LACE into its component parts: LA and choline.
They have determined that aqueous humor LA concentration using ALA solution (2.8%, 0.121M) was lower than the effective 50µM/L in vitro, but LACE solution (3.4%) delivered almost 100µM/L. Magnitudes higher concentration of ALA in eye drops did not deliver the theoretical therapeutic levels.
For in vivo experiments authors used only LACE (5%). I think it would be neat to have another "control" group of mice treated with plain ALA solution, as as we know, we cannot be 100% sure of translating conclusions from in vitro experiments to in vivo.