The primary objective of this study is to compare the level of agreement between clinical defocus curves and the web Democritus Digital Acuity Reading Test (wDDART), which is a web-based digital near and intermediate vision reading test.

The 'defocus curve' assessment technique aims to simulate different distances from near to far over which the patient's visual acuity (VA) is evaluated. Defocus curves are created by first measuring best-corrected distance and near VA of the examinee. Then, a series of positive- and negative-powered trial lenses are added to the best-corrected distance visual acuity (BCDVA) of the patient's eye. Viewing through the addition of a minus lens creates divergent light rays with the same refractive effect as bringing the eye chart closer to the viewer. For instance, a -2.50 D lens represents the distance of 40 cm.

The "defocus curve" assessment technique is a method used widely for the assessment of the functional vision range following multifocal intraocular lens (IOL) implantation. Since this method is a simulation of the near vision, it would be ideal if near vision could be evaluated objectively with a near vision chart. However, the conventional printed near vision charts are not available for a variety of reading distances. In addition, the measurement of near VA at different distances with a printed reading chart intended for one predefined distance (e.g. printed chart for 40 cm) and the transformation of the reading score at 40 cm to an equivalent score for the examined distances is impractical in clinical setting.

For this reason, a digital reading test that allows the text calibration for all reading distances could be a practical method for the rapid and ease evaluation of the near VA, especially in patients implanted with multifocal IOLs. The web-based digital near and intermediate vision reading test wDDART offers the ability to estimate VA at different distances with automated measurement of the patient-screen distance.

Therefore, the present study aims to investigate the level of agreement between clinical defocus curves and the web-based digital near and intermediate vision reading test wDDART.

Inclusion Criteria:

• Previous cataract lens extraction, age> 40 years, monocular best corrected distance visual acuity > 7/10

Exclusion Criteria:

• Glaucoma, corneal diseases, macular diseases, postoperative opacification of the posterior capsule, former mental diseases

Patients with previous cataract lens extraction will be categorized into the following groups:

1. Monofocal group
2. Monovision group (monofocal IOLs bilaterally)
3. Hybrid monovision group (monofocal IOL in the dominant eye and multifocal IOL in the recessive eye)
4. Bilateral multifocal group (the same multifocal IOLs bilaterally)
5. Premium monovision group [bifocal hybrid IOL (Restor +2.50 diopters, Alcon) in the dominant eye and trifocal diffractive IOL (Panoptix, Alcon) in the recessive eye]