Changes in Aqueous Humor pH After Femtosecond Laser-Assisted Cataract Surgery

Abstract

Cavitation bubbles derived from the photodisruption process in femtosecond laser-assisted cataract surgery lead to an acidic shift of the aqueous humor pH as a result of the transformation of carbon dioxide to carbonic acid. The level of gas bubbles visible after the laser photodisruption does not seem to correlate with this pH shift. Further analysis of femtosecond laser-assisted cataract surgery is necessary.

Safety of femtosecond laser‐assisted cataract surgery: assessment of aqueous humour and lens capsule

“…), and cavitation bubbles derived from the photodisruption process lead to an acidic shift of the aqueous humour pH as a result of the transformation of carbon dioxide to carbonic acid (Rossi et al. ), which might be prone to the intraoperative laser‐induced miosis. However, it is still unknown whether there are toxic substances produced due to photochemical or high‐energy physical effects of femtosecond laser during FLACS.…”

Trabecular Meshwork TREK-1 Channels Function as Polymodal Integrators of Pressure and pH

“…In a predominantly glycolytic tissue such as TM,43 pH i and pH o changes that might modulate the pressure dependence and physiology of TM-resident ion channels could arise from multiple sources that include metabolic activity, proton clearance, buffering, and lactate release. The relative involvement of carbonic anhydrases and concentration of the AH HCO 3 − seem to vary across species, with pH AH ranging between slightly alkaline (∼7.6) in rabbits to acidic (∼7.18) in pigs and neutral in nonhuman primates (∼7.44) and humans (∼7.38) 8,9,14,44. Although its functions in bicarbonate production/transport point at the ciliary body as a critical regulator of pH AH ,45,46 our results are, to the best of our knowledge, the first to identify TM mechanotransduction as a potential target of pH shifts in the anterior eye.…”

“…Although it remains to be seen whether protons regulate (conventional and uveoscleral) outflow, TM mechanotransduction is modulated by acidifications resulting from inhibition of carbonic anhydrases (Trusopt), stimulation of PGF 2α receptors (Xalatan), and a block of β-adrenergic receptors (Timoptol) 8. Another clinical intervention that may transiently affect pH AH and TM signaling is the use of femtosecond laser during cataract surgery, reported to lower pH to <6.4 9…”

“…Intracellular protons are generated by respiration, anaerobic glycolysis, and calcium clearance, sequestered by buffering mechanisms, and extruded via Na + /H + exchange, Na + -driven Cl − /HCO 3 − transport, lactate export, glutamine import, and other processes 4–6. In addition to biological mechanisms, clinical interventions such as cataract surgery, antiglaucoma drugs, and contact lens insertion may lower pH AH from its average level of ∼7.4 to below 6.0 7–9. Although the (patho)physiologic significance of such pH AH shifts has not been studied at the cellular/molecular levels, impetus for such investigations comes from early clinical investigations that showed that metabolic acidosis, diabetic acidosis, respiratory alkalosis, and exercise markedly lower IOP,10–13 and from studies showing that pH affects the delivery and biodegradation of IOP lowering drugs 14.…”

Accumulation of sulfur and phosphorus in the eye’s drainage system in primary open-angle glaucoma

“…Original articles рование дисульфидного мостика является pH-зависимым процессом, а при определенном pH соотношение тиолат-аниона к сульфгидрильной группе является постоянной величиной. Значение pH ВГЖ человека сходно с таковым нейтральной сыворотки и, по разным данным литературы, составляет 7,32-7,60 [19]. Наиболее точные измерения, исключающие насыщение ВГЖ эндогенными веществами в процессе пробоподготовки [20,21], свидетельствуют о более кислой по сравнению с плазмой крови реакции ВГЖ в норме -7,2 [22].…”