Methodological quality of the review: Low confidence
Author: Georgios Labiris, Aspa Toli, Aslin Perente, Panagiota Ntonti, Vassilios P. Kozobolis
Region: Not reported
Subsector: Presbyopia correction with pseudophakic monovision
Equity focus: School children
Study population: Clinic patient
Type of programme: Hospital based
Review type: Other review
Quantitative synthesis method: Systematic review
Qualitative synthesis method: Not applicable
Background: Presbyopia is an age-related refractive condition, where the accommodation of eyes progressively weakens, subsequently leading to impairment of the ability to focus on near objects. Presbyopia symptoms are present in patients after cataract lens extraction. The treatment of such patients is a main challenge of modern ophthalmology. One of pseudophakic presbyopia corrections includes pseudophakic monovision induced by monofocal IOLs. In monovision, one eye is corrected for distance vision and the fellow for near vision. In the majority of the cases, the dominant eye is corrected for distance vision and the recessive one for near vision (conventional monovision). Contact lenses monovision has been known since the early 1960s. However, the first publication of pseudophakic monovision was performed in 1984, by Boerner and Thrasher. In 1999, conventional monovision was first used for the correction of the presbyopia after cataract surgery.
Objectives: To review published literature regarding the efficacy of pseudophakic monovision in the correction of presbyopia after cataract extraction, based on both subjective parameters of patients, such as satisfaction, spectacle independence and dysphotopsia symptoms and also clinical parameters, including visual acuity (VA) at all distances, contrast sensitivity stereopsis and possible complications postoperatively.
Main findings: The present review included 18 descriptive and 12 comparative studies. Among them, 10 were prospective studies and five retrospective. Nine of the studies compared the pseudophakic monovision technique with the multifocal IOLs implantation technique, using refractive or diffractive IOLs, as it was described in most of the studies. One study compared mini-monovision with accommodating IOLs implantation, while two studies compared conventional monovision with modified or crossed monovision.
Patient selection: this was presented to be very crucial for the success of pseudophakic monovision and most surgeons dealt thoroughly with patients’ inclusion and exclusion criteria. The most frequent inclusion criterion was the desire for spectacle independence. Among the exclusion criteria were the following: severe ocular disease, corneal astigmatism, strong ocular dominance, large exophoria, and inability to understand the concept of monovision design. Severe ocular disease was a common reason for exclusion from the studies, as it was believed to have an unfavorable effect on visual rehabilitation. Regarding patients’ age, only studies on adults were included in this review. The participants’ ages varied from 24 to 94 years. A study compared conventional monovision and modified monovision, and the outcomes were associated with age. In another study, conventional monovision was compared to hybrid monovision technique and they found a significant association between age and satisfaction rate.
Monovision method: The kind of IOLs used in monovision design in the eligible studies was reported in 18 studies. Among them, monofocal Acrysof SN60WF IOLs and monofocal IOL (AQ110NV, Canon-Staar) were preferred in eight studies.
Comparative studies: This review included 12 comparative studies, among them eight studies were prospective. Most of the studies compared the pseudophakic monovision with the implantation of multifocal IOLs. It was shown that distance VA was significantly better postoperatively after both techniques. Furthermore, between two groups there was not significant difference concerning distance VA. Pseudophakic monovision and multifocal IOLs could achieve significant improvement of unaided near VA postoperatively (P<0.001). A study highlighted pseudophakic minimonovision for spectacle-free life in patients after cataract surgery. All patients achieved good distance and intermediate visual acuities (logMAR 0 and 0.10, respectively), while a remarkable reduction of near vision was described (63.33% had logMAR 0.30). Hybrid monovision was selected for presbyopia correction by Lida et al. The mean binocular VA at all distances was at least 0.10 logMAR, with significantly better results for binocular vision than monocular vision from 0.50 to 5 m (P<0.05). In addition, binocular contrast sensitivity was better than monocular in the eye with multifocal IOL.
Methodology: Inclusion criteria included both comparative and descriptive studies on adult patients in this review. The eligible articles and abstracts were scanned diligently, and the following data was extracted: article information, surgical data, patient selection, clinical parameters, spectacle independence, patients’ satisfaction and possible complications.
A systematic search for relative studies was carried out by authors based on PubMed, Medline, Springer, Nature, Scopus, Journal of Cataract and Refractive Surgery and American Academy of Ophthalmology databases using the search terms below: pseudophakic monovision; monovision and presbyopia; monovision and cataract; mini-monovision; monovision review; monovision and monofocal IOLs; monovision and multifocal; monovision and lens implantation. The search took place in July of 2015. The initial search was performed without search filters and language restrictions.
Applicability/external validity: The authors presented hybrid monovision as a new method to treat the symptoms of presbyopia. Patients who underwent this method had significantly better VA outcomes at all distances binocularly than monocularly. This new technique may be a suitable option for patients younger than 60 years, as especially in this age group satisfaction rate was at high levels.
Geographic focus: Not discussed.
Summary of quality assessment:
In conclusion, this review was attributed low confidence, as important limitations were identified. The authors have not reported how the quality of the included studies were assessed and what method was used. The authors did not report if the screening of the full text was done by two reviewers independently. In addition, the results were not well presented – the list and characteristics of the included studies was not provided.