A Problem and a Promising Solution

Our work together began with a curious letter. We both practice in South Dakota, and we began corresponding because Dr. Nelson’s chronic headache patients were finding relief after being fitted with contoured prism lenses at Dr. Krall’s practice. This curiosity and a need to care for our overlapping patients eventually led to the initiation of the Chronic Daily Headache Study in 2013.

THE STUDY DETAILS: Dr. Nelson

The study initially started at my general neurology group practice but became so large that we built a headache center to accommodate all of the patients interested in participating in the feasibility study.

Patients enrolled were those who had recalcitrant symptoms untouched by previous treatments. They were having chronic headaches, defined as a headache at least every other day for 3 months. This study with Dr. Krall’s contoured prism lenses was the only thing I had left to offer my patients. And to get a 50% response rate in headache medicine is impressive against the general population of migraine patients.

We started with 186 patients, with only seven lost to follow-up. We kept data for 90 days on these patients, and we had 81.6% positive response among patients wearing the contoured lenses (Figure 1).¹ Of these patients, 54% reported their headaches were substantially reduced or gone. In my experience, this does not typically happen in headache medicine. Also, from those 179 patients, we had 50% of patients report nearly a 50% decrease in their headache medications—an impressive number for this population. Many migraine headache patients are young, reproductive-age females² who prefer not to be on medications, therefore a nonpharmacologic treatment is especially beneficial in this group.

TREATMENT WITH CONTOURED PRISM LENSES: Dr. Krall

When you look from one place to another, your eyes move about 90%, and your head follows. If the position of your eyes isn’t aligned to the next target, one eye is telling your head to turn one amount, and the other is telling your head to turn another amount. Soon there’s a disconnect in the back of your head, along with the stimulation of your trigeminal nerve, and the combination of those things causes symptoms of visually induced trigeminal dysphoria: headache, eye strain, neck tension, dry eye feeling, etc.^3,4

When we understood that the misalignment between the eyes was the cause of these symptoms and the need to correct the problem at both distance and near was the solution, we developed a lens with contoured prism (Figure 2). While standard prism lenses only address eye misalignment at a single distance, this technology uses a contoured prism and provides effortless eye alignment at all distances by gradually increasing the prism from distance to near, which relieves over stimulation of the trigeminal nerve.⁵

Another important finding of the Chronic Daily Headache Study is that patients stopped taking many of their medications (Figure 3) within 90 days of wearing the contoured lenses. Nearly 30% of the patients stopped needing 90% of their medications; 50% stopped taking more than 50% of their medications.¹

SURVEY DATA

Based on the positive results of the Chronic Daily Headache Study, we conducted a survey of 360 patients fitted with contoured lenses and found that 82% would recommend the contoured lenses to their friends and family, despite the out-of-pocket cost. Participants completed surveys at 90 days and 1 year after receiving their contoured prism lenses (Figure 4).⁶ The survey included only one question: “Would you recommend this to your friends and family?” The response was greater than 90%.

The participants were given two pairs of glasses fitted with the contoured prism lenses (a pair for close work and a pair for wearing in the sun). If they needed their lens changes when they stopped taking some of their medications, we changed their lenses.

In addition to the Chronic Daily Headache Study, we initiated a Digital Vision Syndrome (DVS) Study.⁷ The American Optometric Association (AOA) defines DVS, or computer vision syndrome, as the physical eye discomfort felt by many individuals after 2 or more hours in front of a digital screen. The perceived causes of this, according to the AOA, include poor lighting, harsh glare on the screen, improper viewing distances, and poor posture.6,8 This population group (n = 22; ages 17 to 51 years) had less severe symptoms, and yet we achieved the same type of response. Nearly 60% of the participants reported their symptoms resolved completely when reading, working on the computer or doing daily activities; 27% said they decreased substantially (Figure 5).⁶

THE TECHNOLOGY BREAKDOWN

The lenses are created based on results from an eye tracking device that can accurately and objectively measure the degree of eye misalignment at distance and near taking into account the following: heterophoria, vergence conditioning, binocular peripheral fusion, fixation disparity, accommodative convergence response and alternating monocular central fixation.⁵

The device measures eye misalignment by providing a real-life simulation of how the eyes work together to see both near (50 cm) and far (6 m, simulating optical infinity).⁵

During the measurement, patients focus on a single point while a dynamic display of rotating planets and stars activates peripheral and central vision to measure distance and near eye alignment (Figure 6). The measurement device isolates peripheral and central vision to provide a comprehensive assessment of the patient’s eye alignment and synchronization.⁵

From this assessment a unique, single measurement of functional misalignment at distance and near, providing a prescriptive range for contoured prism prescription, is generated. The contoured prism lenses offer a solution potentially for all of these patients who have been suffering for years with no result in all the treatments they’ve tried.^6,9 These implications are far reaching, considering the direct and indirect socioeconomic costs of headache to society are estimated at $14 billion per year.²

The measurement device is unique in several facets: it’s 100% objective, and it's fast and efficient for a team to operate and to perform.^10,11 The device allows us to showcase the patients’ results in real time. The device does not, however, measure well esotrope or exotropes. It also does not currently measure vertical misalignments, but I believe this may change in the future. Contraindications for use of this technology include a lack of binocular vision, such as suppression in one eye; inability to achieve binocular fusion; severe strabismus or palsy resulting in greater than 10 prism diopters (D) of misalignment in one eye; greater than 20.00 D of eye misalignment; or greater than 4.00 D of astigmatism in either eye.¹²

This measurement devices works best on patients who are able to sit still and focus on the target. Therefore, in my experience, it is difficult to use in some young children.

COMBATing SYMPTOMS OF DIGITAL EYE STRAIN

Current solutions for eyestrain involve patients making changes in their daily digital habits or environment. These include limiting screen time, increased blinking, and adopting the 20-20-20 rule of taking a 20-second break every 20 minutes to look at something 20 feet away.⁸ Investing in an ergonomic chair, proper lighting, adjusting the computer screen angle, and antiglare screens, etc., are also often suggested.^8,13

There are also other lens technologies aimed at helping digital eye strain. These are designed to cut glare, block blue light from penetrating our eyes, and prevent vision fatigue when staring at digital devices. Marketed as computer eyewear, these lenses are built for the mid-distance range at which we typically view a digital screen, and they can be purchased with or without a prescription. The lenses and filters are customized to reduce blurriness and pixilation, decrease brightness, and minimize glare during prolonged use of devices.¹⁴

CONCLUSION

Based on the research results, we believe this new measurement tool and contoured prism lens technology are more effective than current treatments for computer vision syndrome that primarily address a lack of near focusing power or an attempt to block certain wavelengths of light.