iStent Outcomes in Pseudoexfoliative Glaucoma

Abstract

Purpose : To compare outcomes of iStent with phacoemulsification in primary open-angle glaucoma (POAG) versus pseudoexfoliative glaucoma (PXG) for up to 12 months of follow-up.

Methods : Outcome variables included intraocular pressure (IOP), anti-glaucoma medications used, and visual acuity, which were analyzed with Student’s t-tests and chi-squared tests. Patients were included if maximum preoperative IOP was >21 and at least one preoperative anti-glaucoma medication was used.

Results : 33 eyes in 27 patients were included in this study with 19 POAG eyes and 14 PXG eyes. Overall, mean preoperative IOP was 17.91 ± 5.16 mmHg. After iStent placement, mean IOP was decreased at months 1 (16.79 ± 3.23 mmHg; p=0.12), 3 (15.54 ± 3.28 mmHg; p=0.05), 6 (15.61 ± 3.60 mmHg; p=0.12), 9 (15.42 ± 2.71 mmHg; p=0.06), and 12 (15.78 ± 2.96 mmHg; p=0.07). Mean anti-glaucoma medication usage was statistically decreased from preoperatively (2.18 ± 1.04) at all postoperative visits. Visual acuity showed significant improvement starting at postoperative month 3. By glaucoma type, mean IOP was higher in PXG than POAG eyes at postoperative day 1 (22.79 ± 10.52 mmHg vs. 18.11 ± 8.01 mmHg; p=0.08), week 1 (22.64 ± 7.75 mmHg vs. 16.89 ± 4.43 mmHg; p=0.03), month 1 (18.07 ± 3.60 vs. 15.84 ± 2.63 mmHg; p=0.02), and month 3 (17.89 ± 4.43 mmHg vs. 14.42 ± 1.84 mmHg; p=0.003). PXG eyes required more medications preoperatively than POAG eyes (2.57 ± 1.02 vs. 1.89 ± 0.99; p=0.03), yet PXG eyes required less meds than POAG eyes at postoperative months 9 (0.40 ± 0.55 vs. 1.00 ± 0.86; p=0.05) and 12 (0.17 ± 0.41 vs. 1.42 ± 1.08; p=0.008).

Conclusions : POAG eyes initially experienced increased IOP lowering than PXG eyes until postoperative month 6. PXG eyes initially experienced a rise in mean IOP at postoperative day 1 and week 1 followed by a decline. By 12-month follow-up, PXG eyes had similar IOP lowering than POAG eyes but a greater decrease in glaucoma medication usage. This trend in PXG eyes might be attributed to changes in the collector channel system in the setting of pseudoexfoliative material.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Table 1: iStent Outcomes. Changes in intraocular pressure (IOP), medication usage, and visual acuity after iStent placement as compared to preoperative values.

 

Table 2: iStent Outcomes by Type of Glaucoma. Changes in intraocular pressure (IOP), medication usage, and visual acuity (VA) for 12 months after iStent placement in primary open angle glaucoma (POAG) and pseudoexfoliative glaucoma (PXG).