Comparison of Quality of Vision After Implantation of Monofocal Depth-enhanced Intraocular Lenses in Patients Undergoing Bilateral Cataract Surgery

Cataracts are one of the leading causes of visual impairment and blindness worldwide. Modern cataract surgery by phacoemulsification with intraocular lens implantation is the gold standard of treatment. Conventional monofocal intraocular lenses are still the most commonly used intraocular lenses today. They allow good uncorrected visual acuity to the far distance, while the patient can achieve good visual acuity to the intermediate near distance with glasses.

However, in developed countries, patients expect good quality vision not only to the far distance, but also to intermediate and near distances due to the many daily activities that require this range of vision (reading on tablets and smartphones, driving, carrying on a conversation). To meet these expectations, most intraocular lens manufacturers have introduced extended depth-of-field lens technology, which provides good visual acuity for distance and intermediate distances with few visual side effects. These lenses achieve satisfactory uncorrected visual acuity not only for distance, but also for near and intermediate distances.

Summarising the above arguments, it therefore seems that implanting patients with lenses that allow good distance vision and satisfactory vision to intermediate and near distances can result in an increased quality of life after cataract surgery.

Characteristics of the lenses tested RayOne EMV RAO200E lens (Rayner Intraocular Lenses Ltd) -This lens was developed in collaboration with Professor Graham Barrett. It is a preloaded monofocal+/non-diffractive EDOF, hydrophilic lens that provides an extended range of vision by exploiting positive spherical aberration. The overall diameter of the lens is 12.5mm and the optical diameter is 6.0mm. The lens has an aspherical front surface, biconvex shape. Its effect is to amplify/compensate for the cornea's natural positive spherical aberration, resulting in an increased range of acuity. As it meets ISO standards for monofocal intraocular lenses, it is less affected by variable pupil width, decentration and tilt. The RayOne EMV can be used for bilateral emmetropia and is also optimised for use in a monovision system. For emmetropia, it allows better intermediate vision than standard monovision lenses, providing approximately 1.25 D of extended visual range Vivinex impress XY1-EM (Hoya Surgical Optics, Singapore) - is a new monofocal lens made of hydrophobic non-gloss acrylate with aspheric optics that provides extended depth of field in the intermediate range. It has a combination of standard aspheric and even aspheric surface with microscopic angles. No first studies on the clinical properties of this enhanced monofocal lens are available in the literature.

From the available literature, it appears that both lenses have similar visual improvement efficacy with a similar safety profile. There is currently no study in the available literature directly comparing the two in a randomised manner.