Diagnostics and Drug Delivery: What the Future Holds

Jul 29, 2022
9 min read
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On June 10-11, eyecare practitioners from all over the world gathered online for Eyes On Glaucoma 2022, a two-day educational event all about glaucoma disease diagnosis, treatment, and management.

With so much fantastic education happening at once, we knew that people had to choose which sessions to attend. So over the next few months, we'll be releasing much of the excellent content from Eyes On Glaucoma for you to watch at your leisure—whether for the first time or to review important learnings!

Scroll down to unlock this recording of Dr. Sarah Van Tassel's lecture on innovations in diagnostics and drug delivery, and don't forget to check out our list of future events!

Please note that these videos are provided for review only.

The glaucoma space continues to be flooded with exciting new diagnostics and therapeutics—from in-home monitoring devices to advancements in imaging to taking a more holistic approach to lowering IOP. Knowing what is available and on the horizon empowers clinicians to make the best choices for each individual to achieve optimal results.

Here are a few of the latest and greatest innovations for the diagnosis and treatment of glaucoma.

Measuring IOP at home

With intraocular pressure remaining the key diagnostic measurement for glaucoma, home tonometry is one of the biggest breakthroughs. Using a handheld device with a disposable probe, the patient can produce readings of their pressure at home. The data is then uploaded to the cloud where it can be accessed by their eyecare administrator or even by the patient, depending on which permissions are enabled.

The biggest advantages of in-home tonometry are being able to obtain frequent readings and gaining readings outside of office hours (early morning or at night), which allows for tracking of potential elevations throughout the day. Knowing if the patient is progressing despite a steady IOP may guide treatment, as does the finding of surprise IOP spikes at certain times of day.

In 2017, the iCare HOME was the first device to become available in the US. The iCare HOME 2 has just been released and offers the advantage of achieving readings from supine, reclining, and upright positions. In addition, the device links to a mobile app that is compatible with both iOS and Android. Though there are insurance codes in place for each, reimbursements are low.

As rebound tonometers, these require no anesthetic and for the right patient can be relatively simple to use. So, who is the right patient?

The perfect candidate for in-home tonometry is a patient who is:

  • Progressing in disease despite at-goal IOP measurements in the office
  • Motivated and willing to learn how to properly use the device
  • Sufficiently sighted to see the device and the cues for alignment
  • Can afford either the rental or the purchase

To see a case study of in-home tonometry, watch the full discussion.

Other evolutions in IOP tracking

CATS

Though it looks and acts like a Goldmann tonometer, the correcting applanation tonometry surface (CATS) tonometer reduces corneal biomechanical sensitivity; the sinusoidal shape of this device actually helps neutralize certain corneal properties by matching the curvature of the cornea to provide a “pure” pressure. This product is currently available.

Intraocular IOP measuring

For the future, look for the implementation of intraocular IOP measuring devices, which are available in other countries, but not the US. These technologies, such as the eyemate, are implanted during cataract extraction and then measure and transmit pressure data throughout the day via a reader that is held by the patient. An injectable version, the Injectsense, will be able to acquire and relay measurements without the aid of a reader.

Innovations in imaging

Ganglion cell imaging

Obtaining the ganglion cell layer routinely as part of OCT should be the standard of care. Incorporating ganglion cell imaging into your practice, in support of RNFL, can streamline the diagnosis of patients with suspicious cupping and RNFL thinning, as arcs of ganglion cell loss are clear indicators of glaucoma. Conversely, this imaging can help to rule out the disease.

For case studies on ganglion cell imaging, watch the full discussion.

Gonioscopy

In my practice, gonioscopy remains the gold standard for angle assessment; there is little you can do that will benefit your patients and your practice more than becoming an outstanding gonioscoper. So much can be seen by actually looking at the angle, including subtle pigment dispersion, pseudoexfoliation, and areas of PAS. However, anterior segment OCT is noteworthy and an imaging tool because it may help to predict the progression of glaucoma.

AS-OCT

In the ZAP trial, which looked at 643 Chinese patients with untreated primary angle closure suspect to identify biometric risk factors, they found 34 of the eyes progressed from angle closure suspect to primary angle closure or acute angle closure glaucoma.

In their multivariate models, anterior segment OCT demonstrated that parameters of a narrower, horizontal angle opening distance from the scleral spur and a flatter horizontal iris curvature were significantly associated with progression. This shows the promising role of AS-OCT in predicting the risk of progression in patients with angle closure glaucoma suspect.

OCT-A

OCT angiography, which is widely available with various machines on the market, performs multiple scans in quick succession. Whereas the retinal nerve fiber layer does not change over time, the movement of blood through blood vessels does. OCT-A software can detect and visualize that movement between the images and thus identify blood flow.

In early disease, subtle perfusion changes may occur before ganglion cells have died, so we can intervene and perhaps save that neuroretinal tissue. Similarly, in severe disease, where OCT is no longer valuable, imaging this blood flow could reveal continued progression that would demand treatment.

Home perimetry

In the home perimetry space, virtual reality headsets are on the verge of becoming equivalent to Humphrey perimetry and can serve patients who can't position easily. These headsets can be used at home as well as in-office with both glaucomatous and non-glaucomatous eyes. They retail for approximately $1000.

Digital optic nerve photography

With essentially a glorified magnifying glass and an iPhone, eyecare providers can capture ocular images depicting a range of conditions. In the future, using these same types of tools, patients may be able to capture “eye selfies” at home and send them in for interpretation. The main hurdle will be developing AI software and machine learning programs that can then analyze the photos given the volume of images that would result, thus reducing the need for doctors to interpret every single image.

Better drug delivery, lower IOP

There are a multitude of reasons why patients are non-adherent in the use of glaucoma drops, ranging from forgetfulness to scheduling conflicts to arthritis to downright denial. For many of these patients, the answer could be laser or surgical therapies, but for others those options may not be desired or recommended. One answer to this persistent problem—sustained release delivery systems.

There is one such one commercially available sustained-release glaucoma medication, which was approved by the FDA in March of 2020: Bimatoprost. The Phase 1 and Phase 2 trial data indicated 62% of eyes that received just one implant made it 6 months without rescue, 29% made it to 12 months, and 24% made it 24 months.

Peering forward, the pipeline for sustained-release medications is really robust with candidate systems including:

  • Punctal plugs
  • Ring type systems
  • Implants
  • Microspheres
  • Nanospheres
  • Gels

Determinants of commercial success will include things like efficacy, duration, safety, cost and reimbursement, patient acceptance, and the ease of implementation into office flow.

Thinking “out of the box” about delivery

As providers, it is our job to look for every possible alternative and advancement to improve our outcomes and the quality of our patients’ lives. Here are three nontraditional ways to lower IOP.

Online and compounding pharmacies

If a patient would best benefit from a medication that isn’t readily available at a standard pharmacy, such as preservative-free latanoprost, there are online pharmacies that can fill the order and deliver it direct.

In addition, compounding pharmacies can produce preservative-free drops in unique combinations customized to an individual’s specific ocular needs. This can also be helpful if a medication is cost prohibitive and outside of insurance, as these pharmacies are often much less expensive than their brick and mortar counterparts.

Mindfulness meditation

An interesting study followed 60 patients whose IOP was above goal, were on maximally tolerated medical therapy, and were each scheduled for trabeculectomy. Half added 45 minutes of mindfulness meditation to their existing IOP therapy regimen. At 3 weeks, in the meditation group, the IOP had decreased from about 20 to approximately 15, while those who stayed with drops only just held stable at 20 or 21. Even more impressive, 15 eyes in the meditation group avoided trabeculectomy.

Analysis of trabecular meshwork tissue points to mindfulness meditation altering the chemistry of the eye by upregulating the enzymes responsible for producing nitric oxide in the anterior chamber. This is believed to increase trabecular meshwork outflow. Additionally, the upregulation of neuro-protective genes and down-regulation of proinflammatory genes was observed, all of which may contribute to reduced glaucoma progression.

For more on the effects of nitric oxide and taking a holistic approach to glaucoma, watch the full discussion.

Selective Laser Trabeculoplasty

And last but not least, let us look at SLT’s ability to deliver lower IOP to glaucoma patients. The overwhelming positive results of the LiGHT trial coupled with the new National Institute for Health and Care Excellence (NICE) guidelines should supply confidence in promoting and proposing SLT as first-line therapy.

I am a proponent of offering SLT as a first-line therapy to all of my newly diagnosed patients as well as all patients who come to me on one/two drops from another provider. The previously mentioned issue of drop noncompliance again plays a critical role.

Final thoughts

In closing, this is an exciting time in glaucoma with new technologies available and game-changing innovations in the pipeline. With a broader understanding of these diagnostic tools and therapies, I hope you will be able to utilize some of these strategies to enhance your practice and improve the patient experience.

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About Sarah H. Van Tassel, MD

Sarah H. Van Tassel, MD, is Director of the Glaucoma Service and Glaucoma Fellowship at Weill Cornell Medicine Ophthalmology. Dr. Van Tassel specializes in glaucoma evaluation and treatment, including medical management, laser, and surgical procedures. She also performs cataract surgery …

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