Predictive factors for the IOP reduction in phacocanaloplasty with suprachoroidal drainage

Although the pressure-reducing effect of cataract surgery alone is not very high, it is often cited in the literature. Some authors describe predictive factors correlated with the IOP (intraocular pressure) reduction: in particular noteworthy are age, axial length, preoperative pressure level and the ratio of preoperative pressure/anterior chamber depth. The aim of this study was to determine the applicability of these predictive factors to phacocanaloplasty with suprachoroidal drainage. Setting Eye Clinic Sulzbach Germany.

Retrospective study with a 12-month follow-up, including patients that underwent phacocanaloplasty with suprachoroidal drainage between 2012 and 2014.

Preoperatively, baseline information was collected (including age, diagnosis, medication), and the patients underwent a basic examination and optical biometry. To investigate the relationship between preoperative parameters and the IOP reduction, Pearson's correlation analysis and linear regression were used. Patients with missing data pre- or postoperatively were excluded from the analysis.

The study comprised 89 patients. Mean preoperative IOP was 23.0 ± 5.3 mmHg with 4.0 different antiglaucomatous eye drops. After 12 months, IOP was reduced to 12.1 ± 1.4 mmHg with a median medication of 0.0. The preoperative IOP and the ratio of preoperative IOP/anterior chamber depth were identified as predictive factors. There was no influence of axial length and anterior chamber depth.

Unlike in cataract surgery, anterior chamber depth and axial length have no influence on the pressure reduction caused by phacocanaloplasty. However, a strong predictive factor is the preoperative pressure level. The higher the preoperative IOP, the greater the postoperative pressure reduction.