Intraocular Pressure (Iop) Fluctuations And Visual Field Status: Fluctuation Suppression With Combined Canaloplasty And Trabeculotomy In Open-Angle Glaucoma (Oag)

Reducing the amplitude of diurnal IOP (DIOP) fluctuation has been a desired goal of therapeutics for glaucoma for many years. Surgical intervention with minimally (or micro) invasive glaucoma surgery (MIGS) is becoming increasingly common for mild-moderate glaucoma. Continuous IOP control as provided by surgical management, is not reliant on patient adherence, and should result in a more even and predictable IOP profile over time. The aims of the present study were to compare amplitude in the DIOP profile pre- and post-surgically (canaloplasty and trabeculotomy, OMNI Surgical System) in eyes with OAG, and to assess association between visual field mean deviation (MD) and degree of pre- and post-surgical IOP fluctuation.

Post-hoc analysis of DIOP data collected from patients treated with the OMNI Surgical System (Sight Sciences, Inc, Menlo Park, CA, USA) as participants in the multicenter, historically controlled GEMINI study. The study was conducted at 15 multi-subspecialty ophthalmology practices and surgery centers located in 13 states in the US. The study was IRB approved and  all patients provided written informed consent. The study is listed on clinicaltrials.gov (NCT03861169).

Post-hoc analysis of diurnal IOP (DIOP) data from the multicenter GEMINI study. Patients were grouped into quartiles based on their pre-study MD. Comparisons were made between the 4th and 1st quartiles (best and worst) both preoperatively and at month 12 for average DIOP, average IOP at each diurnal time point, average difference between high and low IOP. One-way ANOVA was used to compare DIOP across quartiles. T-Tests were used for inter-quartile comparisons; paired t-tests or were used for intra-group comparisons. Non-parametric analogs (e.g. Wilcoxon signed rank) were used where normality test failed.

128 patients analyzed were grouped into quartiles (Q) by MD (1: -5.6 to -14.9; 2: -2.8 to -5.6; 3: -1.0 to -2.8; 4: 6.8 to -1.0). Average unmedicated DIOP was similar for all Q preoperative (24.1, 23.5, 23.4, 23.8 mmHg, p=.74) and at month 12 (15.7, 15.8, 16.0, 14.9 mmHg, p=.55). DIOP (month 12) for each Q was significantly lower than preoperatively (p<0.001). Difference between high and low IOP measurement for each patient averaged 2.4, and 3.1, mmHg preoperatively (p=.029) and 1.4, and 1.9 mmHg postoperatively (p=.346), for Q 4 and 1, respectively. Difference in DIOP spread between preoperative and month 12 was significant (Q 1 p=.006) or approached significance (Q 4, p=.118).

Analysis of GEMINI data shows that in addition to significant overall mean IOP reduction, the amplitude of mean IOP was reduced at each of the diurnal time points where IOP was measured. Moreover, 95% of patients had diminished peak IOP post-surgically when compared to the preoperative measurements. IOP fluctuation is an important risk factor for glaucoma progression, independent of IOP alone. This study demonstrates that OAG eyes with mild (Q4) or moderate (Q1) can achieve a similar benefit from decreased IOP and degree of IOP fluctuations for as long as 12 months after surgical treatment with canaloplasty and trabeculotomy.