**1. Introduction**

It has been shown that after phacoemulsification in eyes with and without glaucoma, there is a decrease in IOP in relation to the preoperative one, with a decrease of up to 8.5 mmHg, 34% of the preoperative IOP, in eyes with glaucoma and IOP between 29 and 23 mmHg and 3.4 mmHg; and 18% of the IOP in eyes with preoperative IOP lower than 20 mmHg [1]. Moreover, the decrease in IOP is maintained up to 10 years follow-up without influence of the age of the patients [1]. Therefore, we can affirm that the cataract extraction, regardless of the surgical technique used, provides a reduction in preoperative IOP, maintained during follow-up, which is related to preoperative, both in normal eyes and in ocular hypertensive with or without treatment, and even in eyes with glaucoma and hypotensive medical treatment. Therefore, cataract surgery can be considered as an antiglaucomatous surgical technique, which could the indicated treatment in hyperopic eyes and adequate glaucoma control with medical treatment and in glaucomatous patients, with correct medical control, if we do not pursue a large decrease in IOP [2].

However, when a big IOP decrease is required or in the case of advanced glaucomas, we will use the classic surgical techniques for the treatment of glaucoma: trabeculectomy or nonpenetrating glaucoma surgery, as they present the highest hypotensive efficacy (but also a higher rate of complications than other less invasive techniques).

As an intermediate step, in mild or moderate glaucomas that do not require a high tensional decrease but in which an additional decrease in IOP than that obtained with isolated cataract surgery is needed, we can associate MIGS techniques with cataract surgery, since they offer good tensional responses (although smaller than those obtained with classical glaucoma surgeries) with a lower complication rate (both in number and severity) than with classical surgical techniques. All MIGS have in common a better postoperative recovery compared to other more invasive filtering procedures, the absence of complications associated with the bleb, the respect of the conjunctiva that will allow future techniques if required and the possibility of being performed easily in combination with cataract surgery.

In the following chapter, we are going to talk about the role of the trabecular approach and the MIGS techniques that use this approach associated with cataract surgery.
