In glaucoma management, intraocular pressure (IOP) remains the only modifiable risk factor for prevention of progressive optic neuropathy and visual field loss. Achieving a high level of adherence to IOP-lowering medications is essential for preservation of sight. However, adherence poses challenges to patients and physicians. In the Glaucoma Adherence and Persistence Study, only 10% of patients were persistent with their drops throughout the duration of 1 year.¹

Reasons for poor adherence aren’t a mystery. The side effect profile of topical medications is far from benign. A considerable amount of clinic time is spent counseling patients on common issues such as blurry vision, dry eyes, and ocular and periorbital irritation. Additionally, many patients struggle with proper drop instillation. Most patients report issues adhering to their eye drops.² Mobility and instillation of drops is a challenge as patients age. Cost, access to refills, insurance coverage, and supply chain issues also are barriers to compliance.

To address these barriers, implantable drug delivery systems have been developed with the goal of improving adherence and maintaining consistent IOP control.

Implantable Delivery Systems

The US Food and Drug Administration (FDA) approved the intracameral implant Durysta (AbbVie) in 2020. This unanchored, biodegradable implant contains 10 µg of bimatoprost and is designed to elute the drug steadily over 3 to 4 months without requiring surgical removal. In the ARTEMIS phase 3 trials, adults with ocular hypertension (OHT) or open-angle glaucoma (OAG) were randomized to receive either 10 µg or 15 µg implants or topical timolol. Both implant doses met the primary endpoint, mean IOP reduction from baseline through week 12.³ Corneal endothelial cell loss was observed in eyes with the implants, whereas no endothelial cell loss was reported in the topical timolol group. Subjects with a single 10-μg implant did not develop >20% endothelial cell loss. Iritis was reported in less than 5% of eyes that received the 10-µg implant.

Durysta can be administered at the slit lamp without a trip to the operating room, which makes it more accessible to patients, especially for those with comorbidities that limit their ability to lie flat or receive anesthesia. Currently, Durysta is approved for only 1-time application, due to concerns about endothelial cell loss with repeated dosing.

In 2023 the FDA approved iDose TR (Glaukos), a sustained-release travoprost implant designed to be anchored by its titanium canister in the angle. The implant is expected to elute travoprost for up to 3 years, after which the nonbiodegradable canister remains. Implantation is performed in the operating room through a corneal incision with a clear view of the angle. In the phase 3 trial, patients were randomized to a slow-eluting implant, fast-eluting implant, or topical timolol.⁴ The implant was demonstrated to be noninferior to timolol. Iritis was reported in 6.2% of eyes with the slow-eluting implant. No subject in the slow-eluting group had >20% of corneal endothelial cell loss.

iDose TR can be implanted as a stand-alone procedure or in combination with cataract surgery and minimally invasive glaucoma surgery (MIGS).

There are other sustained drug delivery solutions in the pipeline, including a drug-eluting intraocular lens (IOL) platform being developed by Spyglass Pharma. The platform consists of a single-piece, hydrophobic acrylic IOL with 2 bimatoprost-eluting pads attached at the optic-haptic junction, which are designed to release bimatoprost for 3 years. The lens can be implanted using standard techniques during cataract surgery. Results have been reported from the phase 1/2 feasibility study of 23 patients with OHT or OAG.⁵

Tips for Patient Selection and Counseling

An examination by an ophthalmologist is recommended prior to implantation, with special attention to the cornea, anterior chamber, and angle using gonioscopy.

Implantation may be performed as a stand-alone procedure or in combination with surgery. Cataract surgery provides an ideal opportunity for implantable drug delivery, because it typically does not require additional incisions for the implant.

Patients undergoing intraocular procedures should be counseled on potential risks, including infection, inflammation, and the possibility of future interventions. Iris chafing or close proximity of the implant to the cornea may cause inflammation. If the implant leads to intraocular complications, explantation may be necessary, and patients should be informed of this possibility in advance.

Patients should also be counseled on the need for ongoing glaucoma management once the sustained-release medication falls below therapeutic levels. Continued treatment may include implant replacement, additional implants, other procedures or surgeries, or a return to topical therapy.

During counseling, clinicians should address common patient questions such as “Will this implant cure my glaucoma?” and “Will I ever need drops again?” It should be clearly explained that the goal of an implantable drug is to reduce the need for topical medications for a defined period—“to take a break from a drop” or “to delay the need for a drop”—not to provide a permanent cure.

Preparing for Procedural Success

When implanting Durysta at the slit lamp, both the patient and the physician should be comfortable (Figure 1). To improve ease and stability during the procedure, a wide beam under low magnification is preferred. This provides a broad field of view, allowing small patient movements to remain within the field of view.

To stabilize the globe, use gentle force, such as a cotton-tipped applicator soaked with proparacaine, on the limbus opposite the injection site to provide countertraction.

After injecting the implant, a brief pause before withdrawing the injector from the anterior chamber allows the implant to settle and helps prevent it from being pulled toward the paracentesis.

For intraoperative placement of the iDose TR, a clear view of the angle is essential (Figure 2). The preferred placement is often in the superior quadrant, where the implant will remain covered by the eyelid in primary gaze. Within the angle, the implant should be positioned away from the cornea and without touching the iris.

Malpositioned implants should be carefully repositioned. The iDose TR can be regrasped and adjusted as needed, taking care to avoid damaging the fragile membrane that encases the drug. Physicians placing these implants should also be prepared to explant them if necessary. As such, it is recommended that implantation be performed by surgeons with the appropriate experience and capability to manage potential complications.

Reimbursement Considerations

The CPT codes for pharmaceutical implant procedures are not currently classified as “minimally invasive glaucoma surgery” for reimbursement purposes. Durysta is billed using the permanent J-code J7351 for the drug and CPT code 66030 for the intracameral injection procedure. The iDose TR implant is billed using the permanent J-code J7355 for the drug itself and CPT code 0660T for the implantation procedure. Patients should be advised to contact their insurance providers to discuss anticipated deductibles and copayments.

Preparing for the Future of Implantable Drug Delivery

If current trends in implantable drug therapies are any indication, future options are likely to offer longer durations of drug release. There is also hope that additional drug classes will become available in implantable formulations. Even if the currently available options are not appropriate for a physician’s patients, gaining familiarity with these therapies may better prepare them to adopt future options as they emerge. GP

Ariana Levin, MD, is a glaucoma specialist and professor of ophthalmology at New York University Grossman School of Medicine. She is a consultant to Alcon.

Heeyah Song, MD, is a glaucoma fellow at New York University Grossman School of Medicine. She reports no disclosures. Reach her at Heeyah.Song@nyulangone.org.

References

1. Friedman DS, Quigley HA, Gelb L, et al. Using pharmacy claims data to study adherence to glaucoma medications: methodology and findings of the Glaucoma Adherence and Persistency Study (GAPS). Invest Ophthalmol Vis Sci. 2007;48(11):5052-5057. doi:10.1167/iovs.07-0290

2. Sleath B, Robin AL, Covert D, et al. Patient-reported behavior and problems in using glaucoma medications. Ophthalmology. 2006;113(3):431-436. doi:10.1016/j.ophtha.2005.10.034

3. Medeiros FA, Walters TR, Kolko M, et al; ARTEMIS 1 Study Group. Phase 3, randomized, 20-month study of bimatoprost implant in open-angle glaucoma and ocular hypertension (ARTEMIS 1). Ophthalmology. 2020;127(12):1627-1641. doi:10.1016/j.ophtha.2020.06.018

4. Sarkisian SR, Ang RE, Lee AM, et al. Travoprost intracameral implant for open-angle glaucoma or ocular hypertension: 12-month results of a randomized, double-masked trial. Ophthalmol Ther. 2024;13(4):995-1014. doi:10.1007/s40123-024-00898-y

5. Jarem L. A drug-eluting IOL may help expand glaucoma treatment options. American Academy of Ophthalmology. February 20, 2025. Accessed August 3, 2025. https://www.aao.org/education/headline/drug-eluting-iol-may-help-expand-glaucoma-treatment