Turn Back Elevation of Once Reduced IOP After Trabeculotomy Ab Externo and Kahook Dual Blade Surgeries Combined with Cataract Surgery.

PURPOSE

To evaluate the surgical outcome of internal trabeculectomy by Kahook dual blade (KDB) with that of external trabeculotomy, each combined with phaco-lensectomy and intraocular lens implantation (Phaco).

PATIENTS AND METHODS

This is a retrospective comparative study. The primary and secondary outcome measures are postsurgical intraocular pressure and postsurgical hyphema. One eye each of 76 primary open angle glaucoma (POAG), pseudoexfoliation glaucoma (PEG) and ocular hypertension (OH) patients underwent external phaco-trabeculotomy, and that of 40 POAG, PEG and OH patients underwent phaco-KDB surgery.

RESULTS

Reduction of the intraocular pressure (IOP) by phaco-KDB at one and two years was 28.4 and 27.8%, respectively, and was not significantly different from that by external phaco-trabeculotomy of 32.7% (=0.256) and 31.5% (=0.468), respectively. Three months postsurgical IOP after phaco-KDB and external phaco-trabeculotomy was 16.1 and 15.9 mmHg, respectively. There was a significant turn back elevation of once reduced IOP to 17.1 (=0.0207) and 17.0 mmHg (=0.0096) at 24 months, respectively. There were no differences in success probability to achieve IOP below 17 mmHg (=0.120), 21 mmHg (=0.719) and >20% IOP reduction (=0.309) with medication(s) at two years between the phaco-KDB and external phaco-trabeculotomy cohorts. Younger age was a significant (<0.001) risk factor for failure; however, presurgical IOP (=0.466), the type of surgery (=0.219) and presence of postsurgical IOP spike (=0.737) were not significant risk factors by the Cox proportional hazard model. Hyphema and spike of the IOP in phaco-KDB and external phaco-trabeculotomy cohorts were 40% and 88% (<0.001), and 53% and 41% (=0.238), respectively.

CONCLUSION

The IOP reduction by the phaco-KDB was equivalent to that by external phaco-trabeculotomy up to two years. In both cohorts, once reduced postsurgical IOP tend to increase up to 24 months.