Visual performance of four types of diffractive multifocal intraocular lenses and a review of articles

AIM: To compare the clinical outcomes of a variety of multifocal intraocular lenses(MIOLs) in patients diagnosed with presbyopia or cataracts. METHODS: This clinical trial study included 141 patients(282 eyes) with different MIOLs implantation. The Symfony(60 eyes), the Re STOR(100 eyes), the AT LISAtri(60 eyes), and the Pan Optix(62 eyes) intraocular lenses were evaluated in this prospective interventional study. The near, intermediate, and distant visual acuities, contrast sensitivity, and defocus curve were measured as valid criteria. To statistically analyze the results, we used the Statistical Package for Social Science software, the non-parametric Wilcoxon signed-rank t, the one-way analysis of variance and the Tukey’s post-hoc test in our analysis. Moreover, we conducted a detailed literature search on the Pub Med database in English about MIOLs, in total 59 studies were included in this review article.RESULTS: The four approaches did not show any significant difference in the best-corrected distance visual acuity(P>0.05). The defocus curves at the contrast of 100% showed that trifocal IOLs had better intermediate performance than the bifocal IOL(P<0.05). There were no statistically significant differences between AT LISAtri and Pan Optix lenses for visual acuity at all distances. The eyes with Pan Optix, Symfony, and AT LISAtri IOL showed better contrast sensitivity than those Re STOR at spatial frequencies of 1, 3, and 6 cpd in photopic and mesopic conditions(P<0.001). CONCLUSION: All four groups of the multifocal lenses were satisfying in terms of distance and near vision. Also, the group of trifocal lenses led to satisfactory outcomes in intermediate vision, without degradation in quality of vision.

Refractive surgery: the most cost-saving technique in refractive errors correction

AIM： To compare the lifetime and annual economic burden of spectacles, contact lenses, and refractive surgery in correction of refractive errors.METHODS： This is a cross-sectional study with convenience sampling which 120 patients were interviewed in a tertiary referral hospital in the Iranian health care system. The bottom-up based cost of illness approach was estimated using a face-to-face interview to assess the direct and indirect cost of different refractive errors correction of any correction technologies. RESULTS： Correction with spectacle imposes a total direct cost of US dollar （US$） 342.5 （±8.41） per year and US$9373.5 （±230.1） per lifetime to each patient. These figures for the contact lenses were obtained US$198.3 （±0.12） and US$5203.1 （±256.3） and for refractive surgery were obtained US$19.1 （±1.2） and US$568.1 （±64.6）, respectively. Overall, based on age-adjusted prevalence rates, astigmatism had the highest share of refractive errors economic burden with a lifetime direct cost of slightly less than US$5.49 billion, while hyperopia and myopia imposed less than US$5.24 and 4.2 billion on patients, respectively. The annually imposed cost on each individual Iranian patient with refractive errors is US$308.5. CONCLUSION： Based on 18mo post refractive surgery course observation, which is generalized to whole life, refractive surgery significantly imposed much less cost compared with spectacles and contact lenses. Refractive errors among Iranians result in considerable economic burden. Using the refractive surgery instead of other two correction methods has the ability to reduce this economic loss in the future.

Cost-effectiveness analysis of tele-retinopathy of prematurity screening in Iran

AIM:To conduct a cost-utility analysis of the teleretinopathy of prematurity(ROP)screening program against no screening.METHODS:A decision tree model was developed to identify and treat the infants with threshold ROP through the tele-screening system compared with no screening program from the societal perspective.We used the quality adjusted life years(QALY)index to measure the scenarios’effectiveness,which was discounted for the future years by 0.058.One hundred twenty-six randomly selected newborns with ROP required treatment were investigated to extract the treatment information.We considered the direct medical and non-medical costs in cost calculations analysed by the bottom-up approach.The figures of the model’s inputs were calculated using the Monte Carlo simulation that generated 1000 random iteration of the data,and a one-way sensitivity analysis was performed on the model to cope with the potential uncertainties.RESULTS:The total and per capita needed the budget to establish a tele-ROP screening system were estimated at over 1.5 million and 35.13 USD,respectively.The total cost of identifying and treating an ROP case in tele-screening and no screening strategies were obtained as 108.72 and 63.52 USD,respectively,and their lifetime discounted QALY gained were calculated as 15.39 and 15.11,respectively.Therefore,incremental cost-effectiveness ratio(ICER)of tele-screening strategy against the competitive strategy was achieved as 161.43 USD.CONCLUSION:Tele-ROP screening program is one of the most cost-effective interventions in the Iranian health system and has a high priority to receive a budget for implementation.

稳定型圆锥角膜患者植入新型Phakic角膜接触镜的视觉效果分析

目的:评估可植入式Phakic角膜接触镜治疗稳定型圆锥角膜患者的疗效、安全性、稳定性和可预测性。方法:共14例患者采用植入式Phakic角膜接触镜(IPCL)矫正屈光不正,测量了未矫正视力、最佳矫正视力、离焦曲线、对比敏感度、屈光度及可能的副作用。评估结果超过6mo。结果:平均等效球镜度(SE)和散光在术后6mo末次检查时由术前-6.94±2.79 DS和-4.24±1.42 DC分别变为术后-0.23±0.43 DS和-1.05±0.49 DC。术前平均Snellen视力为0.18±0.10。6mo内未矫正视力和最佳矫正视力平均值分别为0.13±0.10和0.05±0.15。平均安全指数为1.11。所有眼视力均无降低,其中22眼视力提高超过1行。20眼(71.4%)屈光度在0.50 D以内,27眼(96.42%)在±1.00 D以内。术后1wk至6mo,屈光度变化为-0.23±0.43(范围:-1.00至+0.75)。6mo内角膜内皮细胞(ECL)丢失率小于5%。术后6mo眼压(IOP)为11.32±2.28 mmHg。结论:Toric植入式Phakic角膜接触镜在矫正与稳定圆锥角膜相关的近视和近视散光方面具有有效性、安全性和可预测性。

Topography versus non-topography-guided photorefractive keratectomy with corneal cross-linking variations in keratoconus

AIM:To compare the visual results of non-topographyguided and topography-guided photorefractive keratectomy(PRK)applying sequential and simultaneous corneal crosslinking(CXL)treatment for keratoconus.METHODS:Interventional and comparative prospective study.Sixty-nine eyes(36 patients)suffering from keratoconus(stages 1 Amsler-Krumeich classification)were divided into four groups:sequential topography-guided photorefractive keratectomy with CXL,simultaneous topography-guided photorefractive keratectomy with CXL,simultaneous nontopography guided photorefractive keratectomy with CXL,and sequential non-topography guided photorefractive keratectomy with CXL.The main outcome measures were pre-and postoperative uncorrected distance visual acuity(UDVA),best corrected distance visual acuity(CDVA),manifest refraction,contrast sensitivity,and keratometry.RESULTS:All analyzed visual,contrast sensitivity,and refractive parameters showed a significant improvement in the four groups(all P<0.05).A noticeable improvement was seen in keratometry in all the groups,and a remarkable difference was observed between topography-guided groups in comparison to non-topography-guided groups(P<0.05).Interestingly,the improvement in all parameters showed a degree of stability to the end of the follow-up.CONCLUSION:The treatment priorities in all four groups are safety,efficacy,and predictability in the correction of the sphero-cylindrical errors in mild and moderate keratoconus.No significant differences among groups in the recorded objective outcomes were found.