New sustained-release implant treatment available for glaucoma patients
As the glaucoma surgical landscape widens, Grene Vision Group glaucoma specialist Anita Campbell, MD, strives to provide these services to patients in Wichita and rural Kansas.
Glaucoma is a chronic condition that can cause irreversible vision loss if untreated. Typically, elevated intraocular pressure (IOP) will damage the optic nerve axons and cause permanent peripheral vision loss followed by central vision loss.
For each patient with glaucoma, an IOP goal is set based on the health of the patient’s eye. Determining glaucoma eye health involves checking the corneal thickness, or pachymetry, in the front of the eye and the optic nerve in the back of the eye. The doctor observes the optic nerve cupping during a dilated eye exam and uses optical coherence tomography (OCT) testing to check for optic nerve fiber layer loss. Glaucomatous vision loss is measured with visual field perimetry.
Other considerations in setting an IOP goal are patient age, concomitant eye conditions and the maximum eye pressure the patient has had. After determining the eye pressure goal, Dr. Campbell prefers to start with the conservative treatment of eye drops rather than jumping to more invasive options of laser procedures or surgery.
IOP is checked periodically to ensure glaucoma is controlled.
Understanding Problems With Eye Drops
There are myriad reasons that drops may not be sufficient. The drops may not adequately lower the IOP to goal. Some drops are effective but have to be stopped due to allergy that manifests as eye redness, eye burning or rash around the eyelids.
Some patients are unable to administer their drops due to mental or physical limitations, while others don’t understand that their medication is necessary. Often, patients don’t realize that glaucoma is a chronic condition, like hypertension, that requires ongoing treatment. Later in treatment, some patients are in denial about the severity of their glaucoma and don’t prioritize medication use.
Another concern is cost, especially during times with a poor economic climate. For a patient who can’t obtain the medication for a reasonable cost through insurance, Dr. Campbell has found good coverage of generic eye drops at goodRx.com.
For the physical act of administering drops, Dr. Campbell’s team teaches patients a “trick” to use the eye drops.
“I instruct them to lie down and balance the neck of the bottle on the bridge of their nose. They can see the tip of the bottle over their eye. When they squeeze the bottle, either the eye drop falls in or they blink when they see it coming. Then simply tilting their head allows it to fall in,” she says.
This method addresses difficulties due to tremors and arthritic loss of hand strength without trying to wrestle the eyelids open.
Dr. Campbell’s team also coaches patients on how to use drop-assist devices or recommends setting a reminder alarm on their cellphone. Some of the most difficult schedules to work around are second- or third-shift workers who rework their schedule each weekend. For them, Dr. Campbell recommends associating drop use with the same activity each day. For example, always use the medication when you wake up for the day despite that time fluctuating from noon to 5 a.m.
Some patients who have been managing their drops well for years develop dementia and can no longer remember to use the drops. If they have a caregiver, that person may not be available twice a day to administer the drops as needed. Clearly this is a prevalent problem in not just the glaucoma arena but with medication in general.
In the COVID-19 environment, many patients are concerned about attending clinic appointments. Especially for an elderly patient residing in a nursing facility, attending an appointment may mean isolation or quarantine for two weeks, which can worsen depression.
A medication that lasts four to six months can lengthen the gap between appointments and decrease noncompliance concerns.
“We can feel more assured that the patient will receive the medication in a consistent fashion when we use sustained-release medications,” Dr. Campbell says.
Additional Options for Glaucoma Treatment
Durysta is a new sustained-release implant that was FDA approved in March 2020. This is a biodegradable, solid polymer that can be implanted in the anterior chamber to lower IOP and treat glaucoma. It contains a dose of bimatoprost 10mcg that releases the drug in a steady fashion over four to six months. Bimatoprost is a well-known drug in the glaucoma arena. It is a prostaglandin analog (PGA) medication that has been used for glaucoma treatment since 2001 as the brand name Lumigan.
PGAs encourage aqueous fluid to leave the eye through the traditional route of the trabecular meshwork and additionally through the uveoscleral pathway.
The most common side effects associated with PGA drugs are eyelash lengthening and thickening and iris darkening induced by an increase in melanosome production. The Durysta implant is located between the iris and the cornea, so it can still cause iris darkening. However, since this implant is located internally in the eye, it does not cause eyelash lengthening and thickening, skin darkening, loss of periocular fat pads or other changes around the eyelids.
Because Durysta, similar to other PGAs, may cause ocular inflammation, Dr. Campbell avoids offering this drug to those with inflammatory eye diseases such as iritis, uveitis or macular edema. Patients with preexisting cornea pathology, including Fuchs’ dystrophy, are not candidates for Durysta.
The implantation is a well-tolerated, outpatient procedure performed in Grene Vision Group’s minor surgery room with aseptic technique. The patient is required to maintain an upright position for one hour after the procedure.
PGAs are a well-accepted first line therapy for glaucoma. A patient who has been using this drop previously and now is unable to continue due to a change in circumstance, including hand strength or stability or dementia, is an excellent candidate for Durysta. Additionally, patients whose glaucoma is not controlled may benefit from an intraocular glaucoma medication implant.
“Currently, Durysta has been FDA approved for a single dose per eye per lifetime,” Dr. Campbell says. “This may get us over the higher-risk months of COVID-19. In the future, hopefully, this will be a long-term solution for patients to receive their glaucoma medication injection a few times per year and not worry about daily eye drop usage.”
Anita Campbell, MD, is a fellowship-trained glaucoma surgeon providing care in both Wichita and Hutchinson. Her areas of expertise include glaucoma medical treatment and surgical management, including minimally-invasive glaucoma surgery as well as cataract and implant surgery. For more information or to make a referral, contact Grene Vision Group, 316-684-5158 or visit grenevisiongroup.com.