On this episode of Pressure Points Glaucoma, Justin Schweitzer, OD, FAAO, is joined by Nora Lee Cothran, OD, FAAO, to examine how slow- and sustained-release prostaglandin inserts can aid noncompliant glaucoma patients.
Dr. Cothran is a board-certified optometrist specializing in the diagnosis and treatment of glaucoma and neurological eye disease, practicing in The Eye Institute of West Florida in St. Petersburg, Florida.
Case report
A 75-year-old male glaucoma patient presented to the clinic with fluctuating vision after having previously undergone two selective laser trabeculoplasty (SLT) procedures in both eyes.
His best-corrected visual acuity (BCVA) was 20/20 – 1 OU, and he was taking latanoprost each night at bedtime (qhs) OU and timolol once daily OU—although he admitted that he was not compliant with taking these medications.
The clinical evaluation revealed:
- Tmax: 30mmHg OD, 32mmHg OS
- Intraocular pressure (IOP): 17mmHg OU
- Slit lamp: 1+conjunctival hyperemia, 1+ superficial punctate keratitis (SPK), and posterior chamber intraocular lens (PCIOL) OU
- History: (+) Family history of glaucoma
OCT and visual field (VF) testing
Figure 1: Optical coherence tomography (OCT) imaging of relatively substantial retinal nerve fiber layer (RNFL) thinning. The patient also had some mild epiretinal membranes in both eyes, reducing the utility of the ganglion cell analysis for this patient.
Figure 1: Courtesy of Justin Schweitzer, OD, FAAO.
Figures 2 and 3: OD and OS VF testing, respectively, both results were inaccurate (excessive false positives in both eyes); however, a glaucomatous visual field defect or small nasal step was apparent in the visual field test result of the left eye (OS).
Figures 2 and 3: Courtesy of Justin Schweitzer, OD, FAAO.
Initial reflections on the case
Dr. Cothran’s key takeaways from this case were that:
- The patient’s strong family history of glaucoma indicates that they are up to nine times more likely to end up having a more aggressive form of glaucoma.1
- When patients admit that they don’t take their drops, it’s both a cause for concern—as compliance is one of the main factors in successfully managing glaucoma—but should also be viewed as a request for help.
- The SPK and hyperemia indicate that the patient is not comfortable—efforts to preserve the RNFL can only provide so much benefit when the patient is experiencing corneal problems.
Treatment approaches for this patient
According to Dr. Cothran, this patient is a great candidate for Durysta (bimatoprost intracameral implant, Allergan, an AbbVie company), an intercameral pellet that slowly dissolves to dispense bimatoprost over the course of approximately 4 months.
Patients can remain controlled for up to 2 years as a result of a proposed secondary mechanism driven by matrix metalloproteinases (MMPs) and some genetic upregulation.2,3 In her experience, patients who are earlier on in the disease process receive slightly increased efficacy.
She explains that this medication may help to reduce the bottle burden for this patient as it would serve as a replacement for the patient’s prostaglandin, removing his need to take a daily drop to receive treatment.
When discussing this replacement, Dr. Cothran would explain to the patient that this medication will also remove some of the redness and irritation he’s experiencing, potentially due to his eyes drying out as a side effect of the drops he is currently taking.
Although the patient is technically stable from an IOP perspective, once the switch has been made, Dr. Cothran would monitor this metric. She’s often found that when many of her patients are taken off a drop, their IOP lowers further due to previous noncompliance.
In some cases, if the patient is taking two drops, she will also take patients off their second drop and observe them—about a third of her patients end up being stable under their target IOP.
Managing patient expectations with sustained-release implants
To explain the size of the Durysta pellet, Dr. Cothran uses the ball at the end of a ballpoint pen as a visual aid, and likens the way it releases the medicine to an “Alka-Seltzer that dissolves slowly in the eye.” She explains to patients that they won’t see or feel it, but that it will be working in the background.
The one word she never uses when describing the process is “injection,” as it often leads to visceral responses. Instead, she favors the word “insertion,” and explains that it’s done using a microscope in-office, in the same way as a numbing drop is put into the eye.
Following up with patients after insertion
Regarding follow-up, Dr. Cothran has her patients stop the prostaglandin the day they have the procedure, but keeps them on all of their other drops so that she can determine the one-to-one efficacy difference that the Durysta is having.
She sees patients 2 to 3 weeks post-insertion and, using a gonio lens, confirms with the patient that the pellet is located appropriately. She then discusses the prospect of potentially stopping their second drop and lets the patient’s response guide this process.
Dr. Cothran chooses a stepwise approach to give patients confidence in her clinical decision-making while also allowing her to observe the positive progression of the ocular surface.
iDose TR implant
iDose TR (travoprost intracameral implant 75mcg, Glaukos) is another intercameral treatment in the form of a small trabecular eye stent that is mounted into the scleral wall to slowly and continually release a concentrated and proprietary form of travoprost over the course of 3 years.4
This therapy bridges the gap between glaucoma drops and glaucoma surgeries. Unlike the biodegradable pellet, which dissolves at varying rates, iDose TR does not dissolve and is in the form of a stent that releases medication.
Dr. Cothran explains that iDose TR is a good option for patients who have already run out of all of their SLT options, who have already had a bimatoprost pellet, and who don’t qualify for minimally invasive glaucoma surgery (MIGS) at the time of cataract extraction because their cataract surgery was years prior.
Similar to Durysta, the iDose TR increases compliance by allowing patients to take the passenger seat regarding treatment. These patients also have the option of removing some of their other drops should the doctor or patient want to do so.
Conclusion
Ultimately, Dr. Schweitzer’s treatment approach was completely aligned with Dr. Cothran’s proposal. The patient received an insertion of bimatoprost intracameral insert and stopped both of his drops, after which his IOP was lowered to 15mmHg OD and 16mmHg OS.
Dr. Schweitzer agreed that a bimatoprost intracameral insert or a travoprost intraocular insert is the perfect segue following SLT.
