EyeWorld Asia-Pacific September 2020 Issue

EWAP SEPTEMBER 2020 27 CATARACT from cataract surgery), ocular pathology, corneal abnormalities, and endothelial cell count less than 2,000 cells/mm 2 . Patients were examined 1 month after cataract surgery in the second eye. Both groups underwent near (40 cm), intermediate (66 cm; 80 cm), and distance (4 m) visual acuity testing using a Snellen chart with 100% contrast. This was performed under monocular and binocular conditions with and without correction. Defocus curve testing was performed from –4.0 D to +1.5 D in 0.5 D increments using a distance target under photopic lighting conditions. Patients in both groups completed a subjective questionnaire assessing visual satisfaction at near, intermediate, and distance targets. Spectacle independence and hours of spectacle use were also assessed. The mean age of the emmetropic group was 71.7±8.7, and the mean age of the mildly myopic group was 69.1±8.7. The mean postoperative spherical equivalent of the emmetropic group was –0.15±0.29 D, and the mean postoperative spherical equivalent of the mildly myopic group was –0.63±0.31 D. Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) were found to be significantly superior in the mildly myopic group when compared to the emmetropic group. However, there was only minimal reduction in uncorrected distance visual acuity (UDVA) in the mildly myopic group. In their analysis of binocular UDVA, the mildly myopic group demonstrated significantly better vision than the emmetropic group at –4.0 through –0.5 D, and the emmetropic group had significantly better vision than the mildly myopic group at +0.5 through +1.5 D. The emmetropic target group exhibited a non-significantly superior binocular UDVA at 0 diopters on the defocus curve, with the mildly myopic target group remaining very close to 20/20 (logMAR 0.03±0.06). There was no significant difference in binocular corrected distance visual acuity at any point on the defocus curve. The results of the quality of vision questionnaire found that the mildly myopic group had significantly superior visual satisfaction at near while the mildly emmetropic group had statistically significant visual satisfaction at distance. Regarding overall visual satisfaction there was not a statistically significant difference between the groups, although there was a non-significant trend in favor of the mildly myopic group. Non-significant trends toward the mildly myopic target group were also found in responses regarding spectacle independence and hours of spectacle use. Comments As the first study to investigate mildly myopic (–0.40 to –0.75 D) vs. emmetropic (0 to –0.30 D) Yao Ke, MD Professor and Chief, Eye Institute of Zhejiang University, Eye Center of Second Affiliated Hospital of Zhejiang University, School of Medicine 88 Jiefang Road, Hangzhou, China xlren@zju.edu.cn ASIA-PACIFIC PERSPECTIVES I agree with the statement in the article that despite the increasing prevalence and versatility of premium IOLs, monofocal lenses remain the most common IOLs utilized in cataract surgery around the world. In China, due to the limitations of medical insurance and economic conditions, the use of monofocal intraocular lenses accounts for more than 95% of all cataract surgery. In our eye center, the ratio of monofocal intraocular lens to premium intraocular lens is estimated to be 1:10, with 1,300 cases of premium IOL implantation last year. Several of our previous studies have shown that compared with monofocal intraocular lens, multifocal intraocular lenses and extended depth of focus (EDOF) IOLs can provide a wider range for depth of focus. However, multifocal intraocular lenses have some cons, such as contrast sensitivity decrease and dysphotopsia symptoms. In our recent study, we found that dysphotopsia symptoms, especially halos and stars, were more likely in the EDOF IOL (ZXR00) group, whereas hazy vision mainly appeared in the zonal refractive multifocal IOL (LS-313 MF15) group. 1 Moreover, the selection of patients for premium IOLs is very strict. Therefore, the monofocal intraocular lens still plays an irreplaceable role in cataract surgery. In our clinical practice, for the majority of patients who are implanted with monofocal IOLs, we prefer to target both eyes to–0.25 D rather than emmetropia. In the last 2 years, however, we’ve preferred micro-monovision, i.e. to target emmetropia for the dominant eye and myopia of –0.25 D to –0.50 D for the non-dominant eye. The satisfaction of such patients is often higher than that of patients with binocular emmetropia and micro-myopia. Sometimes we design micro-monovision targeting –0.75 D to –1.00 D in the non-dominant eyes of patients who hope to read, but not too often. We find these patients will have better distant and intermediate visual acuities with an increased DOF, but without the complaint of stereopsis loss. Unfortunately, we have not yet carried out planned clinical studies. As the author said in the article, this study was limited by its retrospective nature, single surgeon/center design, and small sample size. We suggest to design a prospective multicenter study on monofocal IOL implantation to compare binocular emmetropia, binocular mild myopia, and micro-monovision, so as to provide better monofocal IOL implantation projections for cataract patients. Reference 1. Song X, et al. Visual outcome and optical quality after implantation of zonal refractive multifocal and extended-range-of-vision IOLs: a prospective comparison. J Cataract Refract Surg . 2020 Apr;46(4):540-548. Editors’ note: Dr. Yao declared no relevant financial interests. two groups. Group 1 included 30 patients who received bilateral monofocal IOLs with a near emmetropic target (0 to –0.30 D), and Group 2 included 30 patients who received bilateral monofocal IOLs with a mild myopic target (–0.40 to –0.75 D). Exclusion criteria were previous ocular surgery (aside