An investigational bimatoprost-eluting intraocular lens (IOL) system produced sustained intraocular pressure (IOP) reductions of approximately 35% at 12 months in patients with mild-to-moderate open-angle glaucoma (OAG) or ocular hypertension (OHT) undergoing cataract surgery, with reductions comparable to those achieved with topical timolol, according to interim results from a phase 1/2 clinical trial. These new phase 1/2 data build on positive top-line results released in March.
The findings were presented at the 2026 American Academy of Ophthalmology annual meeting. The study compared the safety and initial IOP-lowering efficacy of 2 doses of the bimatoprost drug pad-intraocular lens (BIM-IOL; SpyGlass Pharma) system vs a commercially available IOL and topical timolol 0.5% (control) in adults with mild-to-moderate OAG or OHT undergoing cataract surgery.
The BIM-IOL system is designed to incorporate glaucoma therapy into routine cataract surgery without requiring specialized surgical techniques, according to Fiaz Zaman, MD, an ophthalmologist with Houston Eye Associates and a lead investigator for the BIM-IOL phase 1/2 and phase 3 pivotal trials. The system is implanted into the capsular bag, sparing the angle for future surgeries if needed. The BIM-IOL system is currently being evaluated in 2 pivotal phase 3 trials.
The system consists of 2 identical drug-eluting pads attached to the optic-haptic junctions of the SpyGlass IOL. Implanted during standard phacoemulsification cataract surgery, the system is designed to provide continuous, near zero-order elution of bimatoprost for up to 3 years. The system remains investigational and has not received US Food and Drug Administration (FDA) approval.
Study Design and Patient Characteristics
The prospective, multicenter, randomized, double-masked, controlled phase 1/2 trial included 104 evaluable patients assigned in a 2:1:1 ratio to receive the BIM-IOL system containing 78 μg of bimatoprost (n=51), the system containing 39 μg (n=23), or a commercially available IOL with twice-daily topical timolol 0.5% (n=30). Patients receiving either BIM-IOL dose used artificial tears twice daily. All IOP-lowering medications were washed out before baseline measurements.
The primary efficacy endpoint was time-matched IOP reduction at 8 AM and 10 AM at 2, 6, and 12 weeks. Additional outcomes included IOP reduction through 3 years, visual performance, and safety. The mean age of participants was 70.2 years, and 51% were female. Of the 104 patients, 88 (85%) had mild-to-moderate OAG and 16 (15%) had OHT. At screening, 33% were receiving no IOP-lowering medications, 41% were receiving 1, 14% were receiving 2, and 12% were receiving 3. Demographic characteristics were broadly balanced across treatment arms at baseline.
IOP Reductions Sustained Through 12 Months
At the 8 AM assessment, mean IOP reductions from baseline were 8.85 mmHg (34%) in the 78-μg group, 11.36 mmHg (42%) in the 39-μg group, and 9.14 mmHg (35%) in the timolol control group. At the 10 AM assessment, mean reductions were 8.36 mmHg (33%), 9.98 mmHg (40%), and 9.07 mmHg (35%), respectively.
The 12-month efficacy analysis included 48 patients in the 78-μg group, 22 in the 39-μg group, and 30 in the control group. The presentation characterized the overall findings as approximately 9 mmHg of IOP reduction from baseline, corresponding to a reduction of approximately 35%.
Most BIM-IOL Patients Remained Drop Free
At 12 months, 98% of patients receiving the 78-μg BIM-IOL and 96% receiving the 39-μg BIM-IOL remained free of additional IOP-lowering medications. All patients in the control group also remained free of additional medications while receiving their assigned topical timolol.
Visual Acuity and Refractive Outcomes
Best-corrected distance visual acuity (BCDVA) of 20/20 or better was achieved by 74% of eyes in the 78-μg group, 65% in the 39-μg group, and 63% in the control group. BCDVA of 20/25 or better was achieved by 92%, 83%, and 93% of eyes, respectively. All eyes across the 3 groups achieved BCDVA of 20/32 or better. The mean BCDVA across all treatment groups was approximately 86 letters, equivalent to approximately 20/20 vision. At 12 months, mean manifest refraction spherical equivalent values reported in the presentation were 0.44 D in the 78-μg group, 0.34 D in the 39-μg group, and 0.28 D in the control group.
Safety Outcomes Comparable Across Groups
At 12 months, adverse events were reported in 21 patients (41%) receiving the 78-μg BIM-IOL, 10 patients (43%) receiving the 39-μg BIM-IOL, and 11 patients (37%) in the control group. No serious adverse events, secondary surgical interventions, or explantations were reported.
Mean endothelial cell density at baseline was 2611.93 cells/mm² in the 78-μg group, 2576.52 cells/mm² in the 39-μg group, and 2524.92 cells/mm² in the control group. At 12 months, corresponding values were 2290.66, 2103.78, 2270.21 cells/mm². According to the presentation, safety outcomes were comparable across all 3 treatment arms, with endothelial cell loss remaining stable through the 12-month interim analysis at levels consistent with routine cataract surgery.
Study Limitations
The investigators identified several limitations, including the interim nature of the 12-month analysis and the need for longer follow-up to assess the durability of IOP control and safety. Complete masking of the operating surgeon was not possible because of the surgical methodology, although masking was maintained for all IOP measurements. Patients entered the trial while receiving 0 to 3 IOP-lowering medications and underwent varying washout periods, an approach the investigators described as consistent with standard glaucoma trial practices. Additionally, because enrollment was restricted to patients with OHT or mild-to-moderate OAG, the applicability of the findings to patients with more advanced disease remains undetermined.
“Today, relatively few glaucoma patients receive an intervention beyond topical medications at the time of cataract surgery, representing a missed moment in glaucoma care,” said Dr. Zaman. “For these patients, there remains an important opportunity to address both visual restoration and sustained intraocular pressure management within a single procedure.”
Dr. Zaman explained that because the procedure builds on standard phacoemulsification—a well-established and widely performed surgery—it may offer a practical approach for addressing cataract and glaucoma together. “If supported by further clinical evidence and, ultimately, approved for use, the BIM-IOL system could broaden treatment options for patients with both conditions and contribute to how we approach their care.”
Dr. Zaman added, “From a patient perspective, the potential impact extends beyond clinical outcomes. Reducing or eliminating the need for daily glaucoma drops may lessen treatment burden and support adherence, while making a meaningful difference in patients’ day-to-day lives. For someone accustomed to managing drops every day, greater freedom from that routine can be a significant change.”