Dietary change and preservatives exposure, sedentary life, reduced water intake, and confounding medical disorders are factors for stone formation.
Concomitant use of multiple ocular hypotensive agents may be inconvenient and has been associated with increased risk of drug washout [ 5], decreased adherence and persistence [ 6, 7], increased exposure to preservatives and risk of preservative-related ocular surface disease [ 8, 9], and potentially higher treatment costs [ 10].
Benefits of prescribing a FC agent for patients with glaucoma or ocular hypertension may include improved adherence, persistence, convenience, and reduced exposure to preservatives.
In addition, once-daily dosing may result in cost savings as well as less exposure to preservatives such as purite, sofZia (Alcon, Fort Worth, Texas), or benzalkonium chloride [ 27, 28].
These include potentially lower cost, simplified treatment regimens, improved treatment compliance, reduced risk of drug washout, and decreased risk of corneal and ocular surface damage associated with cumulative exposure to preservatives [ 8– 12].
There is strong evidence from both clinical and animal studies that chronic exposure to preservatives, particularly BAK, induces ocular surface changes, conjunctival inflammation, subconjunctival fibrosis, apoptosis of conjunctival epithelial cells and corneal surface changes [ 6, 9, 11, 13].
Increased exposure to preservatives may have untoward effects on the ocular surface and may lead to a higher incidence of ocular signs and symptoms, and poor compliance [ 4, 6– 8].
Formaldehyde is widely used in manufacturing and as a preservative and disinfectant, although workplace exposures have decreased over time because of tighter regulations.
By contrast, the results consistently indicated a positive association between PCDD/PCDF blood concentrations and exposure to wood preservatives in private homes.
One study found a nonsignificant but highly elevated occupational risk (Hertzman et al. 1990); another found a link to exposure to wood preservatives (Seidler et al. 1996); and a third found an increased risk for those having worked on construction sites (Herishanu et al. 2001).
