**3. Considerations before cataract surgery**

The surgical criteria should be early, avoiding advanced cataracts requiring higher ultrasound power or poor posterior pole exploration. The final visual acuity after retinal surgery and the underlying retinal pathology for which vitrectomy was required to predict the visual prognosis of the patient should be identified through the anamnesis: retinal detachment with or without macular involvement, proliferative diabetic retinopathy with or without macular edema, history of ocular trauma or high myopia, among others. At times, it is difficult to determine whether the degree of visual impairment in the patient is due to underlying retinal pathology or to cataract progression. In patients operated on for macular disease who present metamorphopsia or central scotoma, these symptoms will persist after cataract surgery. Likewise, it is important to identify the time interval between vitrectomy and cataract, since when opacity occurs at intervals of less than 4 months, iatrogenic lens touch in the posterior capsule must be ruled out. [20]

In the ophthalmological examination, pupillary dilation should be evaluated, as in uveitic or diabetic eyes, and the state of the zonular fibers, since there may be phacoiridodonesis due to alteration of the zonule in vitrectomized eyes. It is important to perform a fundus examination to rule out retinal pathology and, occasionally, to perform an optical coherence tomography (OCT) to assess the status of the macula. In patients with macular edema, the need to treat it with an intravitreal injection before surgery or during the procedure itself will be assessed. In the case of not being able to visualize the fundus, an ocular ultrasound should be performed to assess the state of the retina and be able to rule out complications such as vitreous hemorrhage or retinal detachment that require combined surgery.
