Dilation Is Routine for Optometrists — But Should It Be?

For many new grads, dilation is as concrete and basic as any other part of our exam. It feels as though we’ve been doing DFEs as part of our comprehensive exams since the beginning of time. If one were to imagine a universe where we didn’t dilate, the result would resemble a very bland episode of The Twilight Zone.

However, dilating our patients has not always been that simple. Dilation has a very interesting history in optometry. The events of the past and current issues have shaped our relationship with the procedure today and will continue to do so into the future. As far as dilation goes, there’s much more than meets the eye (pun intended).

The first optometric licensure law was passed nearly 120 years ago, but optometrists have only been able to dilate patients for the last 50. That privilege was not without some blood, sweat, and tears. In the late 1960’s, optometrists were beginning to grow restless with some aspects of practice. They were able to solve many of their patients’ problems through means of refractive correction (spectacles and contacts) but hit a dead end when the phoropter was not able to provide normal vision. While they could use their direct ophthalmoscopes to view the posterior pole, it didn’t always give them enough information to solve the problem. They were forced to refer their patients to the ophthalmologic community and often didn’t see the patients back.

So it was in 1970 when a group of budding optometrists met at hotel near LaGuardia Airport in New York and decided to do something about expanding their scope of practice.1 The meeting is now famously known as the La Guardia Conference. After battling with the medical community, optometric advocates were able to pass legislation in Rhode Island that gave optometric doctors the opportunity to dilate patients. Many states soon followed suit.

One of the biggest arguments the medical community had against optometry using dilating drops was optometry’s lack of training using the medications and lack of skill in the diagnostic procedures (BIO) performed after dilation. Optometry countered this argument by arranging for a number of ODs in the VA system, who gained the ability to dilate before any non-VA doctors, to go out train the legions of practitioners eager to gain dilating privileges. Optometry’s access to diagnostic pharmaceutical agents (DPAs) was built by practitioners proving their proficiency in skills like slit lamp fundus examination and binocular indirect ophthalmoscopy. The only way to prove the proficiency was through practice and the only way to practice was to dilate A LOT of people. It’s not hard see how dilation became an integral part of the comprehensive exam. But that begs the question, what are we gaining by dilating all of our patients?

There’s no argument that patients with retinal pathology or at moderate risk for such pathology require routine dilated exams. But what about healthy, asymptomatic patients? The data seems to suggest that number of issues uncovered is relatively low. In a retrospective chart review of 1094 patients seen by board certified ophthalmologists, abnormal retinal findings were noted in 53 patients.2 30 of these patients had issues that were considered clinically significant. 3 of those 30 patients had these clinically significant problems in their peripheral retina. In total, about 0.2% of asymptomatic patients had retinal pathology that would have been missed without dilation.

In another study, 592 asymptomatic patients received a DFE in 1998 and then again 10 years later.3 Of the 592 patients, 10 had clinically significant peripheral retinal findings. Of those 10, no cases prompted treatment. Over the same 10 year period, 29 new retinal detachments were found in patients at the same facility, and 26 of the 29 patients were symptomatic. The 3 asymptomatic detachments occured in eyes with significant vision loss and were not treated. The authors concluded that, “In the absence of symptoms, routine DFE seems to have a very low yield for discovery of serious ocular events and appears to be ineffective in altering the course of incidental findings.”

As a profession that prides itself on practicing evidence based medicine, the routine nature of dilating our patients regardless of condition doesn’t seem to align with the data on clinical necessity. The question then becomes, “why is dilation universally a routine procedure?” Part of the reason most likely stems from the history of dilation in optometry discussed earlier, but it's not the whole reason. It is likely that two other major factors play a role; malpractice claims and exam billing.

The main reason optometrists are sued is due to failure to diagnose a condition. The three primary conditions that come up in claims are glaucoma, retinal detachment, and tumors. Dilation is critical in the correct diagnosis of these conditions. In at least one case, failure to dilate was the entire reason the doctor lost the suit. These facts are covered very extensively in the modern optometric curriculum. So it’s not coincidence that we are liberal in our use of tropicamide.

However, if you put into perspective the number of suits optometrists face, it is relatively small. From 1991 to 2008, malpractice claims against optometrists made up approximately 0.2% of total claims against healthcare providers. Of those claims, optometrists pay out, on average, on 30 claims a year. That’s 1 claim for every 1429 optometrists in the US.4

Again, if our relationship toward dilation is influenced by risk of litigation, the data seems to suggest the chance of sued is relatively low.

It would be naive not to mention billing and coding as a potential influence to our relationship with dilation. While neither intermediate or comprehensive vision codes (92xxx) require dilation as an exam element, posterior pole examination is required for comprehensive exams. And dilated 90D is a heck of a lot easier than undilated, especially in geriatric patients with small pupils. For E/M exams, dilation is absolutely required to bill a 99204, 99205, or 99215, and for practical purposes is required for 99203 and 99214 exam as well. If every patient is dilated, it gives offices more billing freedom and can be based on complexity of diagnosis and treatment without having to worry about meeting the appropriate number of exam elements.

When you add all of the different perspectives together, it's not hard to see why dilation has become routine for optometry. We fought hard for the right to dilate our patients and part of that fight was proving our proficiency. We do it often to maintain our skills. Add on top of that some of the most sight threatening conditions are much better detected with dilation and that it is required for billing purposes, and it seems silly not to dilate. Yet, in patients free from retinal pathology and at low risk for developing it, we almost never find any clinically significant problems in the peripheral retina. All these elements hold different weight in the mind of every practitioner which may be why some do it at every exam and others can rarely be found with a BIO on their head.

Optometry’s relationship with dilation is ever changing. With the accessibility to wide field retinal photography (Optomap) increasing significantly, it will be interest to see how the relationship continues to change. At a personal level, your clinical decisions are yours. You have earned the right to determine your practice style and its relation to current standards of care and best practices. Use the most current and accurate information available to guide you on your way.