IOP-lowering and drug-sparing effects of trabectome surgery with or without cyclodialysis ab interno

To compare the postoperative intraocular pressure (IOP) after ab interno trabeculectomy (AIT; trabectome surgery) alone or combined with cyclodialysis ab interno (AITC).

Forty-three eyes with insufficiently controlled open-angle glaucoma were included in this consecutive case series. All eyes received AIT, combined with phacoemulsification and IOL-implantation in phakic instances, with or without additional cyclodialysis ab interno. Postoperative visual acuity, IOP, number of IOP-lowering medications and complications were registered over 12 months.

A total of 19 eyes (14 patients) received AIT and 24 (19 patients) received AITC. Both groups were comparable for baseline IOP (AIT: 19.7 ± 8.2 mmHg; AITC: 19.4 ± 6.8 mmHg; p = 0.96), there was a comparable IOP reduction after 6 months (AIT: - 3.8 ± 12.3, median (interquartile range (IQR)): - 3.8 (- 7.8-4.8) mmHg; AITC: - 4.9 ± 8.3, median (IQR): - 2.0 (- 10.8-2.0) mmHg; p = 0.95) and 12 months (AIT: - 4.3 ± 6.6, median (IQR): - 4.0 (- 8.0 to - 1.0) mmHg; AITC: - 3.7 ± 6.7, median (IQR): - 1.5 (- 5.5 to - 0.5) mmHg; p = 0.49). While final visual acuity was similar between the groups, they differed regarding topical IOP-lowering medications (baseline: AIT 2.9 ± 1.2 and AITC 2.9 ± 1.2; 1 year after surgery: AIT 2.6 ± 1.5 (p = 0.16) and AITC 1.3 ± 1.3; p < 0.001)). Depending on the definition, a complete or qualified success of 33.4-45.8% was achieved in AITC compared to 15.8-21.1% in AIT.

The additional suprachoroidal outflow when AIT is combined with cyclodialysis ab interno (AITC) seems to result in an additional drug sparing effect for at least 1 year without critical safety signals. Thus, AITC might be further investigated prospectively prior to advocating its use in routine minimally invasive glaucoma surgery.