*2.3.11 B-mode ultrasonography*

*Current Cataract Surgical Techniques*

*2.3.6 Aberrometry*

aberrations [29, 30].

*2.3.8 Specular microscopy*

ECD decline of less than 1000 cells/mm2

*2.3.9 Macula and ONH OCT - OCTA*

*2.3.7 Pupillometry*

*2.3.5 Scheimpflug tomography/placido-based corneal topography*

especially if a laser refractive surgery has been preceded.

Scheimpflug tomography or, alternatively, placido-based corneal topography can determine patient's total or anterior-surface corneal astigmatism, respectively, and whether the astigmatism is regular or irregular, or even detect possible keratoconus. The corneal topographic analysis should be compared with optical biometry findings for the best possible accuracy in IOL power and astigmatism calculation,

The routine preoperative examination should include the determination of the anterior aberration profile looking for elevations of 3rd- and 4th-order aberrations, such as coma and spherical aberrations (SA) [27]. Generally, cornea has an average positive SA of +0.28 μm (positive SA occurs when the peripheral rays entering the eye are focused in front of the central rays) [28]. Among the most common aberrometers are i-Trace aberrometer (Tracey Technologies Corp., Houston, TX), OPD-scan (ARK 10000; Nidek), and Pentacam (Oculus Optikgerate GmbH, Wetzlar, Germany), which calculate total ocular, lens or corneal wavefront

Preoperative pupillometry can measure: (i) pupil diameter under photopic (small pupil) and mesopic (wide pupil) lighting conditions, (ii) distance between the pupil center and the visual axis (angle kappa), between the corneal center and the visual axis (angle alpha), and/or between the pupil center and the corneal center, and (iii) distance (spatial shift) from the photopic to the mesopic pupil center (pupil center shift - PCS) [31–33]. Regarding PCS, two types of PCS can be evaluated: (i) measured PCS, which results from the values measured under photopic and mesopic lighting conditions, and (ii) interpolated PCS, which depicts the predicted spatial shift between a photopic pupil of 2 mm to a scotopic pupil of 7 mm, and can contribute to the better comparability of the measurements [34].

Endotheliometry, especially in suspicion of endothelial dysfunction/dystrophy, is a very useful examination. The average endothelial cell density (ECD) in patients

postoperatively might cause significant postoperative endothelial cell impairment

Since good macular and optic nerve function are necessary for a premium pseudophakic presbyopic correction, many surgeons perform an optical coherence tomography (OCT), or even an OCT angiography (OCTA), of the macula and optic nerve head (ONH) to confirm normal macular and optic nerve anatomy and microcirculation. Macular degeneration, subtle epiretinal membranes, early stages of macular hole or posterior vitreous separation with vitreal macular traction, but also glaucoma or vascular abnormalities in various optic neuropathies

[35]. A central

preoperatively, and 400 to 700 cells/mm2

> 40 years old ranges between about 2500 and 2700 cells/mm<sup>2</sup>

and corneal edema. The hexagonality should also be assessed [36–38].

**98**

can be revealed.

This examination could be performed to detect the posterior segment disorders, especially in suspicion of retinal detachment, vitreous opacity or posterior segment tumor, especially when the fundoscopy is impossible due to mature cataract.
