New published study on IOPtiMate multicentre trial
Geffen et al. recently reported updated data from an 111-patient open-label study between 2007 and 2011 across nine sites spanning seven countries (Mexico, India, Russia, Italy, Spain, Switzerland and Israel) on BioLight’s IOPtiMate device. IOPtiMate is carbon-dioxide (CO2) laser-assisted sclerectomy (CLASS) system designed to reduce IOP for the treatment of glaucoma. Recruited patients had definitive glaucoma diagnoses and baseline IOP above 18mmHg despite taking maximal tolerated topical IOP-lowering (hypotensive) drug therapy and, given the stage of their disease, were all indicated for filtration surgery (trabeculectomy).
As discussed in our initiation report, BioLight believes the IOPtiMate CLASS system provides a safer and more precise alternative to trabeculectomies and glaucoma drainage implants (GDIs), with comparable IOP-lowering levels, a lower risk of complications, shorter recovery times and fewer post-op office visits. The IOPtiMate CLASS procedure involves cutting a section (flap) of sclera, temporarily lifting it and applying the CO2 laser beneath, to thin the scleral wall underneath. One of the risks with CLASS described in this study is that excessive thinning of the sclera can lead to macroperforations, which require additional corrective treatment (such as trabeculectomy).
In the study, complete success was defined as IOP measurements of 5-18mm Hg and an IOP reduction of at least 20% compared with baseline IOP, without the need for future hypotensive medications or repeat surgery. Qualified success referred to patients meeting the same parameters, but also included subjects who required hypotensive medications post-operatively.
Failure was defined as an IOP outside the above range, an IOP reduction below 20% compared to baseline IOP, severe loss of vision, intra-operative device-related macroperforations, or the need to undergo additional glaucoma procedures other than goniopuncture or bleb needling (two relatively minor in-office surgical procedures that can accompany glaucoma surgeries, and have low complication rates). Goniopuncture was performed in 18 (18.5%) patients and needling in 12 (12.4%) patients. In both cases, the procedures were performed in the first year of the study and there were no procedure-related complications.
Comparable IOP lowering efficacy to trabeculectomy
Data were collected on all 108 enrolled participants who received IOPtiMate CLASS treatment, and no technical device malfunctions occurred. The efficacy data are cited below and overall show an IOP reduction of 43-47% across the three years, which is comparable to the levels generally associated with trabeculectomy. Nearly 58% of patients reached complete success and did not require IOP-lowering medications after 24 months; the qualified success rate reached a peak of 91% at this period, although we highlight that both groups included patients requiring additional needling or goniopuncture procedures.
Exhibit 1: Efficacy data for IOPtiMate multinational study
Time Period |
Mean IOP reduction (%) |
*Complete success rate (%) |
**Qualified success rate (%) |
12 months |
45.1 |
60.2 |
79.6 |
24 months |
46.8 |
57.9 |
91.2 |
36 months |
42.5 |
47.8 |
84.8 |
Source: Geffen N, Mimouni M, Sherwood M, et al. J Glaucoma. 2016 Dec; 25(12):946-951. Note: *IOP measurements between 5-18mm Hg and an IOP reduction of at least 20% compared with baseline, and without the need for medications or added surgery. **Same as complete success rate, but including patients requiring IOP-lowering medications.
IOPtiMate-related adverse events manageable without lasting visual effects
There were five CLASS procedure-related macroperforations (4.6% of patients) that occurred as a result of excessive scleral tissue ablation. The study authors indicate that each case was successfully converted to trabeculectomy. They suggest that as CLASS has a learning curve, the rate of macroperforations could decrease as surgeons become more familiar with the treatment technique. There was also a relatively high rate of iris incarceration (nine cases, accounting for 8.3% of patients). In all cases, the iris incarcerations were successfully treated with YAG laser iridoplasty or surgical iris repositioning. Nonetheless, the reported rate of iris incarceration was typically higher than would be expected with GDIs, MIGS or filtration surgery.
IOPtiMate appears to carry less risk than filtration surgery
While this was an open-label study, some of the adverse-event levels can be compared to data from the the Tube vs Trabeculectomy study (TVT), a five-year investigation that compared tube shunt surgery to trabeculectomy. The rates of hyphema and hypotony (both shorter-term post-surgical risks) for IOPtiMate were 4.6% and 2.8%, respectively, compared to 8% and 5%, respectively, for the trabeculectomy arm in the TVT study.
Best-corrected visual acuity (BCVA), likely the most significant long-term parameter affecting patients’ visual function and quality of life, appears to show a more striking difference between trabeculectomy and IOPtiMate. The current IOPtiMate study showed that after three years, only 0.9% of patients experienced a significant BCVA loss of at least two Snellen chart lines. However, 43% of patients undergoing trabeculectomy in the TVT study experienced BCVA loss based on the same criteria. We note that differing time measurement periods (three years for the IOPtiMate study vs. five years for the TVT trial), may complicate direct comparisons between both studies.
While this IOPtiMate study shows that a reasonable number of treated patients had non-visually threatening adverse events (macroperforations, iris incarcerations, or events requiring goniopuncture or needling procedures, etc), they were largely well managed and did not appear to affect visual outcomes.
Limitations of current comparisons, possible directions for future studies
While this study suggests IOPtiMate may offer comparable IOP reduction to trabeculetomy and an overall safer profile, comparisons are limited by the absence of a control group, which may have affected subjects’ randomization and treatment masking, and added subjectivity to the analysis. Thus, a direct comparison with trabeculectomy may not be fully reliable based on this study alone. The authors also suggest that a further limitation of this study is the loss of subjects to follow-up, which reached 58% at three years and may have led to selection bias. Finally, visual field deterioration (one of the hallmark parameters to measure glaucoma progression) was not evaluated during this study.
Hence, we estimate that further studies will be needed to persuade eye surgeons (particularly in developed markets) of the potential advantages of IOPtiMate vs competing glaucoma procedures, and strengthen the commercial case for the product. Further, as also stated in our initiation report, GDIs and minimally invasive glaucoma surgeries (MIGS) are increasingly replacing trabeculectomy in many clinical settings, and a more clinically pertinent head-to-head comparison could be done for the efficacy and safety of IOPtiMate to these procedures, rather than trabeculectomy.
