Objective To evaluate the effects of intraocular lenses (IOL) of silicone and polymethylmethacrylate (PMMA) on posterior capsule opacification (PCO). Methods We searched MEDLINE (1966 to 2003), EMBASE (1980 to 2003), Cochrane Central Register of Controlled Trials (Issue 1, 2003) and CBMdisc (1979 to 2003). Only randomized controlled trials (RCTs) were identified. Two reviewers independently assessed the quality of the included trial and extracted data. The following outcomes were assessed: PCO index, percentage of neodymium: YAG (Nd: YAG) laser posterior capsulotomy and visual acuity after cataract surgery. RevMan 4.2 was used for meta-analysis.Results Nine RCTs including 672 eyes were included. In patients with senile cataract, the results of meta-analysis suggested that silicone lens were better than PMMA lens on PCO index (the pooled SMD=－0.92, 95%CI －1.19 to －0.64) and percentage of Nd: YAG (the pooled OR 0.35, 95%CI 0.22 to 0.57) with a statistically significant difference, but there was no significant difference on visual acuity (the pooled OR 1.22, 95%CI 0.43 to 3.50) after cataract surgery between silicone lens and PMMA lens. However, in patients with uveitic cataract, the results of meta-analysis showed that PMMA lens were better than silicone lens in visual acuity (the pooled OR 0.38, 95%CI 0.15 to 0.91) after cataract surgery with a statistically significant difference, but there was no significant difference on PCO index (SMD 0.23, 95%CI －0.59 to 1.05) and percentage of Nd: YAG (the pooled OR 1.82, 95%CI 0.47 to 6.95) between silicone lens and PMMA lens. Conclusions Current evidence indicates that silicone lens are superior to PMMA lens in reducing PCO. Further trials with high quality on methodology are required.
To simplify the production process of intraocular lens (IOL) and to solve the problem of lacking adjustable ability, we proposed a novel soft IOL with large-scale adjustable ability and rigid haptics based on heat-assisted method, and gravity-assisted method. Polydimethylsiloxane (PDMS) and rigid material——polymethyl methacrylate (PMMA) were used as the materials for fabricating optical lens (PDMS) and haptics (PDMS and PMMA) through changing the weight ratio of the solution. A lens-smartphone microscopy system was established to replace the traditional digital microscopy to measure the tiny displacements and shape changes. The PDMS lens has excellent optical property through an experiment in which the maximum optical power was around 273.2 D. Experimental results indicated that the maximum optical power of PMMA IOL was 129.3 D, and that in PDMS IOL, however, was only 56.0 D. Thus, the rigid PMMA-IOL has a larger adjustable range. The production process of PDMS was mold-free, rapid, real-time, and highly repeatable and there was no need for a rigorous experimental environment either. This creative processing technology reduced the manufacturing steps from which an optical lens with high transmittance and high resolution, as well as hatics with accurate dimensions, were obtained. The rigidity of haptics affected more intensely than other factors did for improving the pre-displacement and changing the appearance of PDMS lens. Even though the rigidity of PMMA haptics is large enough for accommodating, there are many drawbacks during manufacturing. It is unavailable to rapid fabricate IOL using PMMA. Thus, further work will be required to alter the weight ratio of PDMS material, increase the rigidity, and enhance the adjustable ability of PDMS IOL.
Objective To observe the incidence and related factors of macula hole retinal detachment（MHRD）after phacoemulsification cataract extraction and intraocular lens（IOL）implantation. Methods The clinical data of 10 076 patients(13 625 eyes) who underwent phacoemulsification cataract extraction and intraocular lens implantation were retrospectively analyzed. There are 1228 patients (1853 eyes) with high myopia. All the patients were examined by routine slitlamp microscopy, ophthalmoscopy as well as A- or B-scan ultrasonography. The phacoemulsification cataract extraction with transparent cornea incision or scleral tunnel incision, combined with intraocular lens implantation was performed in all the patients. The followup was ranged from 12 to 126 months, with a mean of （48.2plusmn;31.1）months. The MHRD was confirmed by the examinations of the fundus, B-scan ultrasonography and optical coherence tomography. The incidence of postoperative MHRD and the risk factors were analyzed. Results 10/13 625 eyes (0.073％) with MHRD were observed. 7/1853 high myopia eyes (0.378%) with MHRD were observed. The occurrence time of MHRD was ranged from 9 to 74 months after surgery, with a mean of 38.5 months. The cumulative risk was estimated at 0.16％ (95% confidence interval, 0.05% -0.27%).Conclusions The incidence of MHRD after phacoemulsification cataract extraction combined with intraocular lens implantation is 0073%. The MHRD incidence of high myopia eyes is 0.378%. High myopia may be the risk factor for MHRD.
Objective To compare the effectiveness of aspheric intraocular lenses(IOL) versus spherical IOL in the treatment of cataract. Method Randomized controlled trials comparing aspheric IOL with spherical IOL were identified by searching PubMed (2000 to October, 2008), EMbase (2000 to October, 2008), MEDLINE (2000 to October, 2008), and The Cochrane Library (Issue 3, 2008). Two reviewers independently assessed trials for eligibility and quality, as well as the extracted data. Data were synthesized using RevMan software (release 5) provided by the Cochrane Collaboration. Results A total of 14 trials (1383 eyes) were included for systematic review, and 11 out of 14 studies were included in the meta-analysis. Subgroup analyses were used according to different aberrations of aspheric IOL. The results showed a significant difference in the mean best corrected visual acuity at 3 months after cataract surgery in the AcrySof IQ IOL group with WMD -0.02, 95% CI -0.03 to -0.01(Plt;0.0001). It showed a significantly worse difference in the mean of the best corrected visual acuity at 3 months after cataract surgery in the AcrySof IQ IOL group with WMD –0.02, 95%CI –0.03 to –0.01 (Plt;0.000 1). It showed a significant worse in the mean the best corrected visual acuity in the Tecnis Z9000 IOL group with WMD 0.02, 95%CI 0.01 to 0.03 (P=0.002); and there was no significant difference between the two groups with WMD 0.00, 95%CI –0.02 to –0.03 (P=0.71). The results did display markedly less spherical aberration and total higher order aberrations than eyes implanted with the traditional spheric IOL in all subgroups (WMD –0.06, 95%CI –0.07 to –0.06, Plt;0.000 01, WMD –0.06, 95%CI –0.07 to –0.02, Plt;0.000 1, respectively). The majority of studies suggested significant improvement in the aspheric IOL group in contrast sensitivity, especially at mesopic low spatial frequencies, although some trials showed no significant difference. Conclusion The effectiveness of aspheric IOL is superior to spherical IOL during cataract surgery. No differences in aspheric IOL with different aberration are found in this series, and further study is required.
Cataract combined with retinopathy can seriously affect the vision of patients. Vitrectomy combined with one-stage implantation of multi-focal intraocular lens (MIOL) has been paid more and more attention. The application of MIOL shows potential in improving the visual quality of patients, but its effect is affected by many factors, and refractive drift is a key problem to be solved. At present, the research mainly focuses on cataract patients with high myopia, and further research on other types of retinopathy is needed. In the future, multi-center, large-sample, long-term clinical studies and interdisciplinary cooperation are needed to optimize surgical and management programs to enhance the application effect of MIOL in the treatment of retinopathy and improve the quality of life of patients.