A Randomised Evaluation of Visual Function After Bilateral Implantation of Two Types of Presbyopia-correcting IOLs

Rationale: Since the introduction of intraocular lenses (IOL) in the treatment of cataract, the postoperative accommodative loss of the human eye has been a trending topic. Numerous studies show a high rate of spectacle-independency after bilateral implantation of multifocal IOLs (MIOL). However, glare, halos, and reduced visual acuity under different light conditions are common complaints after MIOL implantation. Due to its unique design, the TECNIS® Symfony Extended Range of Vision ZXR00 IOL (Abbott Medical Optics, Santa Ana, USA, hereinafter referred to as Symfony IOL) is theoretically providing a continuous range of high-quality vision for far, intermediate, and near distances with the same low incidence of halos and glare associated with monofocal IOLs under different light conditions.

The goal of this study is to compare the AT LISA tri 839MP IOL (Carl Zeiss Meditec AG, Jena, Germany, hereinafter referred to as AT LISA IOL) versus the Symfony IOL in terms of postoperative achieved visual acuity at different distances, patient satisfaction (e.g. spectacle-independency, QoL), and postoperative complication profile (e.g. halo's and glare) under different light conditions. So far, there are no published studies comparing both IOLs. Therefore, we will perform this randomized control trial.

Objective: The primary objective of this study is to compare the postoperative visual outcomes in a series of patients bilaterally implanted with the AT LISA IOL versus those bilaterally implanted with the Symfony IOL.

Study design: Single-centre randomised clinical trial. Study population: 30 patients (60 eyes) with bilateral cataract who require cataract surgery.

Intervention (if applicable): Cataract surgery with bilateral implantation of either a Symfony IOL or an AT LISA IOL.

Main study parameters/endpoints: The primary endpoint is the binocular uncorrected visual acuity at 66 cm distance under both photopic and mesopic conditions 13 weeks postoperatively. Secondary endpoints are: binocular (un)corrected visual acuity at far (4 meters) and near (40 cm) under both photopic and mesopic conditions, reading performance, patient satisfaction, and complication profile.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Both lens models used in this study are CE-marked and commercially available. The pre- and postoperatively examinations to be performed in this study are part of the regular medical treatment of patients with cataract who need cataract surgery. There is one more postoperative visit compared to standard cataract surgery. Potential risks, such as postoperative residual refractive error, halo's and glare, associated with multifocal IOL implantation are expected to be comparable or even lower after implantation of Symfony IOL. Spectacle-independency and high quality visual acuity postoperatively are the expected major benefits of implantation of the Symfony IOL.

Inclusion criteria

• Minimum 21 years of age
• Bilateral cataract
• Bilateral implantation of Tecnis Symfony IOL or AT LISA IOL (same lens model in both eyes)
• Expected postoperative astigmatism ≤ 1.00 D (combination with FLACS AK is tolerated up to 1.5 D preoperative astigmatism)
• IOL power calculation between +10.00 D and 32.00 D
• Expected postoperative best-corrected visual acuity of logMAR +0.3 or better
• Availability to undergo second eye surgery within 2 weeks of the first eye surgery
• Willing and able to comply with scheduled visits and other study procedures
• Signed informed consent.

Exclusion criteria

• Previous corneal surgery and/or reshaping
• Clinically significant corneal endothelial dystrophy (e.g., Fuchs' dystrophy)
• Irregular astigmatism
• Keratoconus
• History of corneal disease (e.g., herpes simplex, herpes zoster keratitis, etc.)
• Extensive age related macular degeneration (atrophic or exudative age-related macular degeneration or numerous soft drusen)
• Extensive visual field loss (e.g., glaucoma, history of cerebral vascular accidents, etc.)
• Extensive diabetic macular disease
• History of amblyopia and/or strabismus
• Pseudoexfoliation syndrome or other capsule or zonular abnormalities that could affect postoperative centration or tilt of the IOL
• Pupil abnormalities (non-reactive, tonic pupils, abnormally shaped pupils, or pupils that do not dilate at least 3.5 mm under mesopic/scotopic conditions)
• Cognitive, cerebral or concentration disorders (e.g. dementia, Parkinson, history of CVA, etc.)
• Suturing of incision required at time of surgery
• Complications during surgery of the first eye.