Mini-monovision with monofocal lenses
Research type
Research Study
Full title
Prospective, non-randomised, single arm study on visual and optical outcomes after mini-monovision with hydrophobic monofocal intraocular lens
IRAS ID
335566
Contact name
Mayank Nanavaty
Contact email
Sponsor organisation
University Hospitals Sussex NHS Foundation Trust
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
Summary of Research
The most frequently implanted intraocular lenses (IOLs) are still monofocal lenses, because of their relatively low cost, their excellent outcome for distance, and the low incidence of photic phenomena, in eyes with comorbidities such as corneal or macular diseases. The increasing importance of the intermediate distance tasks in modern everyday life has led to a growing interest toward IOLs that may also reduce spectacle independence for intermediate distances without significant unwanted side effects, thus improving some quality-of-life aspects.1-3 These tasks within the intermediate range often depend on lighting (and con¬sequently pupil diameter) and require additional refrac¬tive correction. Ni et al.4 developed a real-life vision test to analyse the correlation of distance, near, and intermedi¬ate visual acuity with the score in fulfilling several tasks adopted from real-life situations, such as picking fruit and facial recognition at various distances. They found a significant correlation between intermediate vision and the ability to perform these tasks. The more recent IOLs, based on diffractive technology, such as trifocal or extended-range-of-vision (ERV) IOLs, are capable of improving intermediate vision but they are not available on the NHS and they still require an accurate patient selection and neural adaptation to enhance benefits and minimize unwanted visual effects.1-3
Monovision using traditional monofocal IOLs is a surgical option that corrects distance vision in one eye; the other eye focuses intentionally for near to mid-range vision with the same monofocal lens. This leads to the process of neuroadaptation where the brain can use the distance image from the dominant eye and the near image from the non-dominant eye to achieve a wider range of functional vision.5 In this surgery the amount of intended near to mid-range power (myopia) can vary, with full monovision defined as the reading eye exhibiting a residual refractive error of −2.50 diopters or more. Modified monovision or “mini-monovision” requires a smaller interocular diopteric power difference between eyes than traditional full monovision, typical calculations of the eye to focus for intermediate distances are anywhere between −0.75 and −1.75 diopters of myopia. Patients with significant astigmatism can also undergo mini-monovision surgery with astigmatism correction.
The trifocal and ERV IOLs are expensive and therefore not available in the public sector. There is a need for a procedure which give equivalent results without increasing the cost. Whereas, mini-monovision approach with the existing monofocal IOLs (which are available in the public sector) may be an alternative option to give equivalent outcomes comparable to trifocal and ERV IOLs. We designed this study to assess the binocular distance and intermediate visual performance after bilateral implantation of hydrophobic monofocal intraocular lenses (IOL) with mini-monovision in patients with bilateral cataracts.Summary of Results
MINI-MONOVISION AFTER CATARACT SURGERY: CAN STANDARD LENS IMPLANTS IMPROVE BOTH DISTANCE AND INTERMEDIATE VISION?Who carried out this research?
This study was carried out by the ophthalmology research team at Sussex Eye Hospital, part of University Hospitals Sussex NHS Foundation Trust [Chief investigator: Prof. Mayank A. Nanavaty and funded by Alcon Laboratories, USA]. The study took place between [August 2024 and July 2025].Background
Cataract surgery is one of the most common operations performed worldwide, and each year many thousands of people in the UK have this surgery. During cataract surgery, the eye's own cloudy lens is removed and replaced with an artificial lens implant, called an intraocular lens.
Standard intraocular lenses usually give excellent distance vision, but they cannot naturally change focus the way a young, healthy eye does. This means many patients still need reading glasses for close-up tasks, and often struggle with intermediate-distance tasks such as reading a computer screen, using a tablet, cooking, or checking a car dashboard, which can affect their quality of life and independence.Aim of the study
This study aimed to find out whether a technique called mini-monovision, using standard (non-premium) monofocal lens implants, could give patients both good distance vision and good intermediate vision, so that they might rely less on glasses after cataract surgery. Answering this question matters now because more expensive premium lens implants are not suitable or affordable for everyone, so a lower-cost alternative that works well could benefit many more patients.Involving patients and the public
Patients, carers or members of the public helped design this study by giving valuable feedback on the protocol.What did the study involve?
With mini-monovision, one eye is focused for clear distance vision and the other eye is focused slightly for near vision, using standard monofocal lens implants (artificial lenses placed inside the eye during cataract surgery).
The study included 27 patients (54 eyes) who had cataract surgery on both eyes during the same operating session at Sussex Eye Hospital. This was an observational study, meaning patients were monitored after surgery rather than compared against a separate control group. Patients were followed up for three months, during which researchers measured their distance and intermediate vision without glasses, and asked about their visual experience and quality of life using questionnaires.What were the results?
Patients achieved excellent uncorrected distance vision and good uncorrected intermediate vision, and this remained stable throughout the three-month follow-up. Most patients could manage everyday tasks needing intermediate vision, such as using computers and reading text held at arm's length, without glasses. Patients also reported a significant improvement in their quality of life and satisfaction with their vision, finding tasks such as reading, recognising faces, watching television, and using digital devices easier.
The lens implants gave predictable, stable results, and no significant safety concerns or complications were identified. The mini-monovision approach was well tolerated by all participants.What does this mean for patients?
These findings suggest that mini-monovision using standard monofocal lens implants could offer a practical, cost-effective alternative for patients who want to reduce their dependence on glasses after cataract surgery, without the added expense of premium lens implants. This technique is now being offered to NHS patients at the Sussex Eye Hospital.REC name
North West - Preston Research Ethics Committee
REC reference
24/NW/0192
Date of REC Opinion
10 Jul 2024
REC opinion
Further Information Favourable Opinion