Using an anecdotal case study to lay old habits to rest

Image credit: AdobeStock/АннаКовальчук

Old habits die hard. Such an adage is true from a clinical perspective. In terms of retinal vascular disease, I’d say we are likely going to be reliant on fluorescein angiography for the near future. However, there will come a day when injecting dye into a patient’s arm and taking subsequent sequences of fundus photos to diagnose a disease, stage a disease state, or monitor a patient’s response to treatment will no longer be necessary. That day will come, and countless clinicians will continue fluorescein angiography studies well past their date of obsolescence. From an ocular surface disease perspective, we are already well beyond the point of, “Here’s a bottle of whatever artificial tears I have a sample of; see you when your vision benefit will pay for another eye exam.”

I grudgingly raise my hand, as I am guilty of such behavior. From a myopia control perspective, the World Health Organization has already made it common knowledge that most of the population of the planet will be myopic by the year 2050.¹ Yet most clinicians I speak with are still not facilitating the availability of myopia control to their pediatric patients. From an age-related macular degeneration treatment perspective, there are medications that can slow the progression of geographic atrophy beyond what oral supplements can do, yet many clinicians do not yet facilitate the availability of these medications to their patients.

Now, this is a glaucoma column, as evidenced by the title above my seemingly random collision of thoughts. So let’s turn the conversation back to the topic at hand (took me long enough, I’d say). I think it’s time to update the eagerly reading clinician on what is perhaps the most poorly designed study in the history of eye care. The sample size: 6 patients. The potential for bias: very high. The evidence grade: quite low. The study type: I suppose a prospective cohort. The control: laughably, none. The principal investigator, statistician, evidence collator, and author: me. The peer-reviewed journal in which the study was published: The Journal of Balding Middle-Aged Optometrists. The number of calls I will get from the American Optometric Association’s Evidence-based Optometry Committee (on which I sit) chastising me for this: I hope many, as it is just that they launch their complaints accordingly.

So what did I do? It’s simple. I took 6 newly diagnosed glaucoma patients and started them on a prostaglandin analog. The medication of choice: whatever I had a sample of at the time or what insurance would initially cover. The masking of the investigator: none. The diagnosis for my study population: primary open-angle glaucoma. The criteria for a glaucoma diagnosis: I performed my usual and customary glaucoma testing and said so. The ages of my patients: 53, 67, 48, 39, 56, and 76 years. My typical modus operandi has been to give the prostaglandin analog at least a month (up to 6 weeks) to take effect before getting too hasty about switching medications within the same class, adding medication(s), or referring out (I practice in the state of Georgia) for a selective laser trabeculoplasty or minimally/microinvasive glaucoma surgery in order to achieve target IOP (which I am setting at lower values these days). I was taught that clinical approach and I have been practicing it faithfully for just about a couple of decades.

However, I did something different for these patients. I gave the prostaglandin
analogs just 2 weeks to work before seeing the patients back, instead of the typical 4-6 weeks. My results are as follows:

• I set a target IOP pressure of between 30% and 40% below the maximum measured IOP based on the severity of the disease state at the time of diagnosis. To my astonishment, 4 of the 6 patients had achieved their target IOPs at the 2-week IOP check after starting their prostaglandin analogs.
• The 2 patients who did not achieve their targets at that time were scheduled to be followed up within another month for a subsequent IOP measurement. At the time, I authored the assessment to date of this ridiculously poor design of a study in which I had not yet seen those 2 patients for their additional IOP measurement.

Old habits die hard. Will I incorporate my “findings” into a newly adapted contemporary clinical approach to gauging the effectivity of prostaglandin analog therapy in patients with newly diagnosed glaucoma? Probably not just yet. However, I can tell you that I do, indeed, have anecdotal evidence that shows that we may not need to wait 4 to 6 weeks to determine the efficacy of prostaglandin analog therapy. I will say I am intrigued, and I look forward to eagerly reading the well-designed, double-masked, placebo-controlled study you design and author on this subject. Now, get to work.

Reference:

1. Holden BA, Fricke TR, Wilson DA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology. 2016;123(5):1036-1042. doi:10.1016/j.ophtha.2016.01.006