Abstract
Purpose :
To evaluate the effectiveness of trabecular microbypass stent implantation (iStent) in combination with cataract surgery in moderate to severe glaucoma compared to mild glaucoma
Methods :
Medical charts of primary open angle glaucoma (POAG) subjects undergoing phacoemulsification with single iStent (Glaukos corporation, Laguna Hills, CA) implantation from January 2013 to July 2017 at two sites were retrospectively reviewed. Eyes were classified based on mean deviation (MD) of the preoperative standard automated perimetry into mild (MD >-6 dB), moderate (MD -6 to -12 dB), and severe (MD <-12 dB). Mixed effect regression models were performed to determine the effect of iStent on IOP lowering at 1 year. The outcome measures included (1) IOP and number of medications, (2) eyes with IOP≤18 off medication, and (3) eyes with IOP≤15 off medication.
Results :
104 eyes from 89 subjects were analyzed. Number of eyes (subjects) was 32 (25), 39 (35), and 33 (29) for mild, moderate, and severe glaucoma, respectively. At 1 year, cataract combined with iStent surgery significantly lowered the number of medications in all groups and significantly decreased IOP in moderate and severe glaucoma (p<0.05). Average preoperative IOP ranged between 14-17 mmHg. Success with IOP≤18 mmHg was achieved in 71.8%, 23.1%, and 6.1% of eyes in mild, moderate, and severe, respectively. Percentage of eyes achieving IOP≤15 mmHg was 56.3%, 18.0%, and 3.0% for mild, moderate, and severe glaucoma, respectively. (Figure 1) Mixed effect model with adjustment for age, gender, and baseline number of medications found significantly higher number of medications in moderate (ß 0.58 p=0.002) and severe (ß 1.20 p<0.001) compared to mild glaucoma. Eyes with moderate and severe glaucoma had significantly lower rate of success with IOP≤18 (moderate vs mild OR 0.014, p=0.028; severe vs mild OR 0.001, p=0.017). Eyes with severe glaucoma also had significantly lower rate of success with IOP ≤15 mmHg compared to mild glaucoma (OR 0.003, p=0.04).
Conclusions :
Combined cataract surgery with iStent decreases IOP and number of medications in moderate and severe glaucoma at 1 year. However, the effect in these groups was less compared to mild glaucoma.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.