No. 3: Know the hairy aspects in glaucoma medication use. PGAs constitute an important class of glaucoma medications, but they have side effects, including permanent pigment changes in the iris, periorbital tissues, and eyelids; periorbital fat atrophy; intraocular inflammation; macular edema; and eyelash growth.3 A longitudinal, masked, multicenter comparative study reported that 64% to 76% of patients with elevated IOP had at least one adverse effect, mainly ocular hyperemia (ie, red eye) with daily PGA use over 12 weeks.4
Red eye is compounded by the known association of PGAs with meibomian gland dysfunction (MGD). In a prospective, cross-sectional study, 92% of glaucoma patients using a PGA had obstructive MGD, compared with 58% among patients taking other classes of IOP-lowering medications.5
Further, approximately 40% of postchemotherapy patients taking bimatoprost 0.03% for eyelash hypotrichosis had at least one adverse event at 16 weeks, and 47% had at least one adverse event after 1 year.6 These events included conjunctival hyperemia, eyelid pruritus, pigmentation, hyperemia, punctate keratitis, and DED.
No. 4: Beware of OTC eyelash growth serums. Knowing the side effects of prescription PGAs can help you to recognize the same patterns in patients who are using unregulated, drug-laced OTC eyelash growth serums. Nearly one-third of OTC eyelash growth serums contain a PGA, and some do not disclose it on the ingredients label,7 which poses significant issues for consumers (not to mention, PGAs are pregnancy category C). The frequent lacing of OTC eyelash growth serums with PGAs occurs despite US FDA warning letters to cosmetics manufacturers for “misleading statements regarding the product’s safety and [failure] to reveal material facts with respect to consequences that may result from the use of the product.”8
In a survey on OTC eyelash growth serum use, among 154 respondents, 43% said they had stopped using an eyelash growth serum, and, of these, 67% reported that the reason for dropout was side effects (burning, stinging, itching, eyelid pigment change, eyelash loss, sunken eyes).9 If you see any of the telltale side effects of PGA use, ask patients if they are using an eyelash growth serum. If they are, advise them to stop.
No. 5: There is a difference between real science, secret science, and pseudo-science. Prescription medications require transparent, robust, placebo-controlled studies to gain market approval. Head-to-head randomized studies in identical cohorts allow us to make claims such as safer, noninferior, or even better than.
Unfortunately, there is no such data transparency or basis for clinical safety and efficacy claims in cosmetics.10,11 The days of ocular irritancy testing in Draize rabbit models are over, thankfully. These inhumane tests have been replaced by in vitro EpiOcular MatTek assays designed to test ocular irritancy from industrial and household chemicals, personal care products, and cosmetics. In cosmetics studies, a liquid cosmetic is exposed to cultured human keratinocytes for 30 to 254 minutes and assayed for cell death against positive and negative controls (not a typical time frame in expected human use of 8, 16, or 24 hours of wear). If 60% or more of the cells survive that short in vitro, non–real world exposure, the product is considered nonirritating.12
Said in another way, up to 40% of the cells can die from exposure to the cosmetic and the product will still be reported as nonirritating.
This raises significant concerns around cosmetics safety, especially in our ocular surface disease patients. The lab assay protocol versus real-world exposures may help to explain cosmetics users survey data indicating higher Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire scores in patients who do not remove their makeup.13 Cosmetics companies are not required to perform EpiOcular testing; and if they do, the data results are not made public.
Cosmetics performance claims are based on subjective consumer surveys with pooled satisfaction data sets to artificially elevate the percentages. Performance claim studies are performed by cosmetics marketing companies with explicit designs to support cosmetics marketing claims.10 These cosmetics clinical studies are nonscientific marketing studies that do not confer assurances of ocular surface safety because they do not even ask questions around ocular safety and side effects. Even in the European Union, where cosmetics safety regulations are more up to date, cosmetics organizations develop consumer use surveys (often misrepresented as clinical trials) to “undergo the scrutiny of the advertising standards agency” and “instill consumer’s confidence.”10 Subjective performance does not equal consumer safety. We expect to see safety data for the prescriptions we write, so shouldn’t we expect it for the eye cosmetics we recommend?
Even cosmetics safety-in-use studies (ophthalmologist-tested) lack scientific rigor, scientific methodology and transparency. I’ve searched for months and have been unable to find industry standards or regulations for making cosmetic label claims such as safe for contact lens wearers and appropriate for dry eye. These claims as well as suitable for sensitive eyes are based on nontransparent protocols from ophthalmologist testing companies, one of which has had indictments of data fraud.14
Cosmeceutical brands that claim the space between cosmetics and pharmaceuticals have an even higher burden of safety, transparency, performance, and consumer safety expectations.15 In a 2017 study analyzing cosmetic-related adverse events reported to the US FDA, researchers suggested that a form of premarket approval should be considered for such products.16 But since cosmeceuticals are neither recognized nor defined under US FDA law, the legal requirements in this blur zone are the same as those for the weak US FDA cosmetics regulations. Cosmetics companies do not perform studies with pharmaceutical rigor because they don’t have to,11 and yet ocular complications from their products are seen in our clinics often, and the complications are well described in the literature.17 Also, cosmetics are not allowed to make treatment claims,11 so we should view cosmetics claims of suitable for dry eye with healthy skepticism. So when you see cosmetics claims of better than or safer than, ask yourself, “Better and safer than what?”