I recently purchased a bottle of Visomitin from cosmicnootropic.com. It arrived in 20 days from the day I paid. I was very happy with the company. But Visomitin contains 0.1 mg of benzalkonium chloride (BAK) per ml of Visomitin. I don't know the density of BAK, but if it has the same density as water, it would be a concentration of about 0.01%. I did a PubMed search of BAK and found that it's in lots of glaucoma drops. There are lots of paper saying that BAK results in ocular surface disease (OSD), and other preservatives result in significantly less OSD, although one paper said that for a BAK concentration of 0.001%, the incidence of OSD is comparable to drops with the better preservatives.
Here's a description of OSD: "“Ocular surface disease is a multifactorial disorder of the conjunctival epithelium, corneal epithelium, lacrimal glands, and meibomian glands that results in either deficient or inappropriate tear production and leads to decreased visual clarity and ocular discomfort through various inflammatory pathways..."
The source is “Ocular Surface Disease and Glaucoma Medications: A Clinical Approach,” X. Zhang et al., https://www.ncbi.nlm...pubmed/30199425.
The body of the paper says
"BAK, the most commonly used of these preservatives, has also been indicated in initiating or worsening ocular surface disease (Table 1). BAK is weakly allergenic with both time and dose-dependent toxicity on the conjunctiva and cornea. It may initiate or worsen ocular surface disease by destabilizing goblet cells and, subsequently, the tear film by inducing squamous metaplasia of the conjunctival epithelium, disrupting the corneal epithelium by reducing epithelial cell density, and increasing stromal keratocyte activation [15, 29,42,49–51]. Animal studies have shown that medications containing higher levels of BAK resulted in greater corneal damage and conjunctival infiltration than those preserved with Purite or lower levels of BAK52. Ocular surface effects are dependent on concentration, and low concentrations of BAK have been found to be similar in surface toxicity to newer preservatives in the same medication [53]."
Ref. 53 is a study done in which the concentration of BAK was 0.001%.
Another paper said "“Benzalkonium Chloride (BAK), one of the most commonly used preservative agent, is a constituent of approximately 70% of the commercially available anti glaucoma drugs [11]. Various clinical studies have shown that BAK induces corneal toxicity, reduces TBUT [tear film breakup time] and aggravates the dry eye disease in glaucoma patients [12,13]. Nenciu et al. observed that different anti glaucoma drugs containing BAK as preservative lead to various degrees of conjunctival inflammation and metaplasia [14]. Another study reported loss of goblet cells leading to mucin deficiency type of dry eye disease in patients receiving BAK [15]. BAK due to its disruptive properties might lead to its accumulation in various tissues when used for a long period of time [11].”
The source is “Ocular Surface Disease with BAK preserved Travoprost and Polyquaternium 1(Polyquad) preserved Travoprost,” K. Suresh et al.
https://www.ncbi.nlm...pubmed/31687627
Another paper said that OSD incidence is higher in patients with glaucoma, and evidence suggests it is caused by the preservatives and not the active ingredient in the drops.
I stopped using Visomitin. I have the beginnings of cataracts, but I'm going to look for other methods to delay their progression or eventually get surgery if needed.
