Posterior Intraocular Lens Research Articles

Pars plana vitrectomy with posterior iris claw implantation for posteriorly dislocated nucleus and intraocular lens

We evaluated the safety and efficacy of pars plana vitrectomy (PPV) with primary posterior iris claw intraocular lens (IOL) implantation in cases of posterior dislocation of nucleus and IOL without capsular support. This was a retrospective interventional case series. Fifteen eyes underwent PPV with primary posterior iris claw IOL implantation performed by a single vitreoretinal surgeon. The main outcome measures were changes in best corrected visual acuity and anterior and posterior segment complications. A total of 15 eyes were included in this study. Eight had nucleus drop, three had IOL drop during cataract surgery and four had traumatic posterior dislocation of lens. The final postoperative best corrected visual acuity was 20/60 or better in 11 patients. This procedure is a viable option in achieving good functional visual acuity in eyes without capsular support.

Noncontact common-path Fourier domain optical coherence tomography method for in vitro intraocular lens power measurement

We propose a novel common-path Fourier domain optical coherence tomography (CP-FD-OCT) method for noncontact, accurate, and objective in vitro measurement of the dioptric power of intraocular lenses (IOLs) implants. The CP-FD-OCT method principle of operation is based on simple two-dimensional scanning common-path Fourier domain optical coherence tomography. By reconstructing the anterior and posterior IOL surfaces, the radii of the two surfaces, and thus the IOL dioptric power are determined. The CP-FD-OCT design provides high accuracy of IOL surface reconstruction. The axial position detection accuracy is calibrated at 1.22 μm in balanced saline solution used for simulation of in situ conditions. The lateral sampling rate is controlled by the step size of linear scanning systems. IOL samples with labeled dioptric power in the low-power (5D), mid-power (20D and 22D), and high-power (36D) ranges under in situ conditions are tested. We obtained a mean power of 4.95/20.11/22.09/36.25 D with high levels of repeatability estimated by a standard deviation of 0.10/0.18/0.2/0.58 D and a relative error of 2/0.9/0.9/1.6%, based on five measurements for each IOL respectively. The new CP-FD-OCT method provides an independent source of IOL power measurement data as well as information for evaluating other optical properties of IOLs such as refractive index, central thickness, and aberrations.

Delayed postoperative opacification of foldable hydrophilic acrylic intraocular lenses

Phacoemulsification and implantation of a foldable intraocular lens for cataract is almost a routine procedure in ophthalmic practice. Late postoperative opacification of hydrophilic acrylic (hydrogel) intraocular lenses (IOLs) has been reported, but the appearance differs from our findings. We report clinical, pathologic, ultrastructural, and spectroscopic analyses of foldable hydrogel IOLs undergoing late opacification resulting in visual disturbances. This retrospective study comprised 486 patients (550 eyes) who had implantation of a foldable hydrogel posterior IOL. Three cases (three eyes) had been found to have opacification of the IOLs. The three lenses were exchanged because of significant visual disturbances, and were examined using light microscopy, scanning electron microscopy and energy dispersion X-ray (EDX) spectroscopy. Incisional biopsies of the capsular membrane in contact with the opacified IOL were performed in one patient. The mean interval between implantation of the hydrogel IOLs and the diagnosis of opacification was 35.3 months (range, 34-36 months). All three of the cases had quiet anterior chamber. No obvious posterior capsular opacification were found. The best corrected visual acuity of the three cases who had exchanged IOLs were all 20/25 or better. Microscopic analysis revealed multiple, fine, granular structures both on the surface and matrix of the opacified IOLs. EDX analysis showed the presence of calcium and phosphorous were within the granular structures. Histological examination of capsular membrane did not reveal any evidence of calcium salts or special pathological exchanges. Further studies should be undertaken to determine the incidence and possible mechanisms of this phenomenon.

Intraocular lens dislocation after whole-body vibration

We present 2 cases of intraocular lens (IOL) dislocation that appeared shortly after the patients exercised on a vibration platform. The first patient was a 71-year-old woman who presented with lens subluxation in her right eye and a complete posterior IOL dislocation in her left eye. The second case was a 62-year-old woman who presented with unilateral IOL dislocation within the capsular bag in her right eye. Timing from IOL implantation to dislocation was approximately 6 years and 4 years, respectively. Pars plana vitrectomy with removal of the dislocated IOL was performed in both patients. Whole-body vibration training has become increasingly popular as a form of exercise training. It reportedly may provide benefits in physical function and in some diseases, especially in older people. However, evidence-based protocols ensuring safety and efficacy in this population are lacking. We discuss vibration as a cause of late IOL dislocation.

Long-Term Visual Acuity and its Predictors after Cataract Surgery in Patients with Uveitis

To analyze the outcomes of phacoemulsification and posterior intraocular lens (IOL) implantation in patients with uveitis and to determine factors responsible for poor visual outcome. The records of 155 patients (180 eyes) with uveitis who had phacoemulsification and IOL implantation between August 2001 and March 2008 were examined retrospectively. Best-corrected visual acuity (BCVA) was recorded at the immediate preoperative visit and at follow-up examinations every 3 months. At each postoperative visit, a complete ophthalmologic examination was performed. The postoperative visual outcomes and complications were analyzed. Univariate regression analysis was done to determine risk factors for poor visual acuity during follow-up. The mean follow-up was 31.4 months (range 3-78 months). An underlying systemic disease was present in 70 (45.2%) patients (82 eyes, 45.6%). The mean preoperative logMAR BCVA was 1.13 +/- 0.62 (95% CI: 0.85-1.02) and increased to 0.42 +/- 0.57 (95% CI: 0.32-0.59) at last medical visit (p < 0.001). A total of 107 eyes (59.4%) had postoperative complications including posterior capsular opacification, newly developed macular edema, recurrence of uveitis, macular epiretinal membrane, and deposits on the IOL surface. Preoperatively observed macular lesions was the factor most strongly associated with poor visual outcome after cataract surgery (odds ratio: 5.43; 95% CI: 3.41-7.34; p < 0.001). Anterior segment pathologies, age at surgery, etiology of uveitis (idiopathic, uveitis associated systemic disease), and gender did not influence visual rehabilitation after surgery (p > 0.05). The outcomes of phacoemulsification and IOL implantation in patients with uveitis were satisfactory. Patients with observed preoperative macular lesions are at risk for poor visual outcome.

The influence of surgery and intraocular lens implantation timing on visual outcome in traumatic cataract

To compare the visual outcome of primary versus secondary traumatic cataract extraction and primary versus secondary intraocular lens (IOL) implantation. The medical charts of consecutive patients who developed cataract following open and closed-globe injuries and were referred to our institute were reviewed. The best-corrected visual acuity of the patients who underwent primary and secondary cataract extraction and those with primary and secondary IOL implantation was assessed at presentation and at the end of the follow-up. Sixty-nine eyes of 69 patients developed cataract after being involved in ocular trauma. Forty-five eyes had open-globe injury and 24 had closed-globe injury. The right eye was involved in 26 injuries and the left in 43. Best-corrected visual acuity (BCVA) of 20/40 or better was not statistically associated with the type of cataract extraction (extracapsular versus phacoemulsification) (in open-globe injury p = 0.181 and in all p = 0.662) and placement of anterior or posterior IOL (in open-globe injury p = 0.196 and in all p = 0.114). The timing of surgery (as immediate surgery or later as a second surgery) and the timing of intraocular lens implantation (during the extraction of the cataract or later in a secondary procedure) were not statistically associated with BCVA of 20/40 or better (in open-globe injury p = 0.322 and 0.381 in all p = 0.460 and 0.450, respectively). Irreversible amblyopia in children was a statistically significant factor for this visual acuity both in patients with open-globe injury (p = 0.036) and in all patients (p < 0.001). In traumatic cataract, the visual outcome did not differ between primary and secondary cataract extraction and between primary and secondary IOL implantation in adults. In the amblyogenic age, primary surgery with IOL implantation should be preferred.

Theoretical strategy for choosing piggyback intraocular lens powers in young children

The normal growth of a young child's pseudophakic eye can result in a large myopic shift. Temporary polypseudophakia using piggyback intraocular lenses (IOLs) has been proposed as a means to reduce the amount of myopic shift by removing the anterior IOL when the eye becomes sufficiently myopic. Since the rate of refractive growth can be used to predict the refractive curve over time in pseudophakic children, we used this knowledge to develop a theoretical strategy for choosing IOL power combinations for temporary polypseudophakia. We used a novel Pediatric Piggyback IOL Calculator to develop a strategy for choosing the powers of the anterior and posterior IOLs. We graphed the predicted results for several combinations of piggyback IOL powers and chose the combination of IOL powers that appeared to give the best results, based on the known rate of refractive growth (5.4 D) and its standard deviation (2.4 D). We aimed for a combination to minimize the hyperopic or myopic refractive error during the first 6 years of life to facilitate amblyopia management and minimize the refractive error at age 20 years. We found optimal results when the initial postoperative goal refraction with polypseudophakia was moderate hyperopia and the anterior IOL had approximately 20% of the total required IOL power. This theoretical strategy can be used to determine piggyback IOL powers to use in children.

Implantation of intraocular lens in children with uveitis : long term visual outcome and prognosis

Abstract Purpose To evaluate long term visual acuity, intra ocular inflammation and late complications for children with chronic uveitis who underwent cataract surgery with posterior chamber intra ocular lens (IOL) implantation. Methods Retrospective, monocentric study of children under 16 with chronic uveitis and who underwent cataract surgery between january 1996 and december 2001. Surgical protocol included : phacoaspiration with posterior capsulorhexis, anterior vitrectomy and IOL implantation. Visual acuity, intra ocular pressure, slight lamp examination, laser flare photometry and anti inflammatory treatment were analyzed at different time points. Results 17 eyes of 12 children (8 boys, 4 girls) were included. Uveitis was bilateral in 6 cases. The mean age at surgery was 10.5 years (ranged from 4 to 15) and the mean follow up time was 8.9 years (from 7 to 13). Diagnosis of uveitis was idiopathic juvenile arthritis in 8 cases (64.7%), sarcoidosis in 1 case and finally no etiology was identified in 3 cases (29.4%). Seven years after surgery, the mean visual acuity was 0.33 logMAR and 82% of children had still an immuno modulatory treatment. Late complications were : glaucoma (11.7%) , Elschnig perls (11.7%) , giant cells on IOL (35%) and CME (6%) of cases. Conclusion IOL implantation in children with chronic uveitis prevents amblyopia and allows rapid visual recovery. Complete surgical procedure in this group of children has interesting results on visual acuity and rehabilitation. Strict and long‐term control of intraocular inflammation is mandatory in order to prevent major complications and blindness. Implantation should not be proposed in young children with JIA‐associated uveitis.

Macular thickness alterations after cataract surgery determined by optical coherence tomography

Abstract Purpose To evaluate macular thickness alterations with optical coherence tomography after phacoemulsification and posterior champer intraocular lens implantation. Methods In this prospective study,201 patients who underwent phacoemulsication(102 men and 99 women)with mean age 65±8years were included.Best corrected visual acuity,complete slit lamp examination with lens and OCT examination were performed in all patients before surgery and at one,three and six months postoperatively.Patients were divided into five groups:Group 1(control group‐100 eyes):patients without any predisponding factors for cystoid macular edema,Group 2(15 eyes):patients with complicated surgery,Group 3(27 eyes):patients with epiretinal membrane,Group 4(35 eyes):patients with diabetes and Group 5(24 eyes):patients with glaucoma. Results The preoperative mean minimal foveal thickness(MMFT)in groups 1 and 2 was 204±24μm and 213±47μm respectively and had no significant changes throughout the follow up period(p&gt;0,05).In groups 3,4 and 5 a significant increase of macular thickness was detected.In group 3 the preoperative MMTF was 248±72μm and at 1,3 and 6 months it was 263±86μm(p=0,01),240±30μm(p=0,18)and 270±64μm(p&lt;0,01)respectively.In group 4 the preoperative MMTF was 219±39μm,after 1month the MMTF increased at 257±78μm(p=0,002),at 3months it was 231±46μm(p=0,005)and at the last examination at 6 months it was 236±49μm(p=0,005).In group 5 the initially MMTF(206±21μm)had significant increase in the first[213±30μm(p=0,07)]and in the third month[223±24μm(p=0,03)]. Conclusion Diabetic retinopathy, epiretinal membranes and glaucoma may predispose to increase in macular thickness after cataract surgery.

Risk Factors of Iris Posterior Synechia Formation after Phacovitrectomy with Three-Piece Acrylic IOL or Single-Piece Acrylic IOL

Aims: To identify the risk factors of posterior iris synechia formation after phacovitrectomy with posterior chamber single-piece acrylic intraocular lens (IOL; Acrysof® SA60AT) or 3-piece acrylic IOL (Acrysof® MA60BM) implantation. Methods: We selected 153 eyes of 153 patients treated by phacovitrectomy between March 2000 and August 2006 and retrospectively reviewed the relationship between iris posterior synechiae and various factors, such as IOL type, tamponade, preoperative iris posterior synechiae, major indications for surgery, axial length and preoperative anterior chamber (AC) depth. Results: IOL type (p = 0.0447), C₃F₈ gas tamponades (p = 0.0074), preoperative iris posterior synechiae (p = 0.0001) and postoperative AC fibrin deposition (p = 0.0303) were significantly associated with postoperative iris posterior synechiae by multiple logistic regression analysis. The odds ratio (OR) for single-piece IOL versus 3-piece IOL was 2.658 (95% confidence interval, CI: 1.010–6.993), the OR for C₃F₈ gas versus balanced salt solution was 4.051 (95% CI: 1.455–11.281), for the presence of preoperative iris posterior synechiae 12.868 (95% CI: 3.511–47.165), and the OR for postoperative AC fibrin deposition was 6.012 (95% CI: 1.186–30.468). Conclusion: Preoperative iris posterior synechiae, C₃F₈ gas tamponade, postoperative AC fibrin deposition and the single-piece IOL could increase the rates of iris posterior synechiae after phacovitrectomy.

Simple method to evaluate adequacy of capsule for foldable intraocular lens implantation in the sulcus

We describe a simple method for evaluating the adequacy of the capsule for implantation of a foldable intraocular lens (IOL) during phacoemulsification complicated by a posterior capsule tear. After cortical lens material clean-up and anterior vitrectomy (if required), 3 knots of 10-0 nylon are tied to the trailing haptic of the IOL using a 3/1/1 configuration. Then, the IOL is inserted into the sulcus. If it is unstable when the surgeon tries to deepen or shallow the anterior chamber, gently pulling the nylon thread will prevent posterior IOL dislocation. Two further attempts to implant the IOL in the other meridians of the capsule are made. The results of using this technique in 10 eyes of 10 patients are reported. Optic decentration occurred in 1 case (10%). No postoperative dislocation was observed, and no patient required surgery for IOL decentration during the follow-up.

Phakic pattern of exfoliation material on a posterior chamber intraocular lens

Editor, Deposits of exfoliation material (XFM) on the anterior lens surface are the most consistent and important diagnostic feature of exfoliation syndrome (XFS). In phakic eyes, the characteristic pattern of XFM on the lens surface consists of three zones: (i) a central translucent disc; (ii) a clear intermediate zone; and (iii) a peripheral granular zone (Ritch & Schlötzer-Schrehardt 2001). The XFM is produced by several tissues of the anterior segment, including the iris pigment epithelium, non-pigmented ciliary epithelium and pre-equatorial lens epithelium. That the lens is unnecessary for the production of XFM is illustrated by its appearance years after cataract on intraocular lens (IOL) implants in pseudophakic eyes (Krause 1989; Ringvold & Bore 1990; Chen & Blumenthal 1992; Ritch 1994; Stewart & Jay 1995; FitzSimon & Johnson 1996). Most of these reports have portrayed scattered flecks of XFM on the surface of the IOL. Recently, two reports have been presented showing a pattern of mature deposition on the surfaces of IOLs years after implantation, suggestive of long-standing production, in patients who had no recorded findings of XFS prior to cataract surgery (Bahadur & Masket 2007; Park & Kee 2007). We would like to add another case of deposition of XFM on an IOL seen 10 years after lens implantation and in which the pattern of deposition reflected long-standing production of XFM with a granular appearance to the material extending over the surface of the IOL. An 82-year-old woman, with no history of glaucoma, presented with blurred vision in the left eye (OS) 10 years after extracapsular cataract extraction and implantation of a sulcus-fixated posterior chamber polymethylmethacrylate IOL. Her best-corrected visual acuity was 0.5 OS. Intraocular pressures were within normal limits. Slit-lamp biomicroscopy revealed XFM deposition on both the anterior and posterior surface of the IOL. The pattern of XFM accumulation on the anterior IOL surface showed a granular peripheral zone and radial striations in the intermediate zone without a clear central zone (Fig. 1A,B). The IOL was well centred and the pupil was round, reactive to light, and free of synechia and XFM deposits. Gonioscopy showed a hyperpigmented trabecular meshwork. The exfoliation material on the anterior surface of the intraocular lens has taken on a configuration similar to that of pregranular exfoliation syndrome, but is also deposited as densely as in phakic eyes with exfoliation syndrome. We feel that the appearance of the XFM on the lens surface in our case, and the others reported recently, can be explained by long-standing production in the absence of lens–pseudophakos friction. In the phakic eye, the central disc of XFM usually equals the pupillary diameter in size, and the intermediate clear zone is caused by friction of the iris on the lens anterior surface, rubbing the XFM off the mid-portion of the anterior lens surface and producing the classic three-ring appearance. When XFM is allowed to build up undisturbed in this region, it develops a granular appearance, similar to that found in the peripheral zone. However, in the presence of an IOL, space between the iris and the IOL prevents this rubbing, allowing the deposition of the material to progress undisturbed. Finally, one wonders why this phenomenon is rare, while XFS is extremely common, as is cataract extraction in these eyes. We conjecture that the distance from the posterior iris pigment epithelium, which produces the XFM, to the IOL is usually too large to allow deposition on the IOL surface and that any XFM secreted by these cells passes into the posterior chamber. Most of the eyes in the two other recent papers and our patient had IOL implantation in the sulcus, which would bring the IOL surface into closer contact with the iris. If the IOL is in the capsular bag but the zonules are loose, allowing the IOL and the bag to come forward, the same situation may apply.

Quantification of glistenings in intraocular lenses using Scheimpflug photography

We describe a method of quantifying glistenings in intraocular lenses (IOLs) using Scheimpflug photography. Glistenings in hydrophilic acrylic IOLs implanted over a 10-year period were quantified subjectively at the slitlamp and by digital image analysis of Scheimpflug photographs; the latter involved analysis of glistenings in the anterior and posterior IOL surfaces. Glistenings were seen in all IOLs, with more in those with a longer postoperative period. This association was stronger with Scheimpflug quantification (r(S) = 0.70; P<.000) than with subjective quantification (r(S) = 0.32; P = .11). Anterior and posterior IOL glistenings developed similarly over time. Scheimpflug photography had a higher degree of objectivity than subjective staging of IOL glistenings and also provided information about the axial localization of the glistenings. This investigation indicated that IOL glistenings continued to increase for up to 10 years.

Comparison of postoperative results after implantation of hydrophilic acrylic or hydrophobic acrylic intraocular lens: Data of one-year prospective clinical study

To evaluate and compare the impact of two sharp-edge optic foldable intraocular lenses (IOLs) of similar design made from different material (hydrophilic acrylic or hydrophobic acrylic) on visual function, anterior and posterior capsule opacification at one-year follow-up after cataract phacoemulsification. Seventy-two eyes of 72 patients scheduled for cataract surgery were included in a prospective clinical study. Two foldable sharp-edge optic posterior chamber acrylic IOLs of similar design were used. Thirty-nine eyes of 39 patients received a single-piece hydrophilic acrylic (PC 511, Ophtec) IOL and 33 eyes of 33 patients - single-piece hydrophobic acrylic (AcrySof, SA60AT, Alcon) IOL. Visual acuity, anterior capsule opacification (ACO), capsulorrhexis/optic overlapping, and posterior capsule opacification (PCO) were evaluated. The intensity of ACO was assessed subjectively. PCO values in the entire IOL optic area and in the central 3-mm optic zone were assessed using a photographic image analysis system (EPCO 2000). The patients were examined at one year postoperatively. There were no significant differences in best-corrected visual acuity and capsulorrhexis/optic overlapping between IOL types at 1-year follow-up after surgery. In the single-piece hydrophilic acrylic IOL group, the grade of ACO density was significantly higher in capsulorrhexis rim area (1.56+/-0.71 and 1.00+/-0.75) and in the capsule/optic area (1.62+/-0.67 and 1.00+/-0.75) (P<0.05). PCO values of the entire IOL optic area (0.12+/-0.13 and 0.024+/-0.02) as well as in the central 3-mm optic zone (0.06+/-0.11 and 0.001+/-0.003) was significantly higher in the single-piece hydrophilic acrylic IOL group one year postoperatively (P<0.05). In 33.3% of cases of the single-piece hydrophilic acrylic IOL group, contraction of haptics to IOL optics was present one year postoperatively, which was not present in any case of the single-piece hydrophobic acrylic IOL group. One-year follow-up after cataract surgery has shown a significant difference in ACO and PCO development comparing single-piece hydrophilic acrylic and single-piece hydrophobic acrylic intraocular lenses. The effect of hydrophobic acrylic foldable lenses on preventing anterior and posterior capsule opacification is mainly a result of the acrylic hydrophobic biomaterial.

Theoretical evaluation of the cataract extraction‐refraction‐implantation techniques for intraocular lens power calculation

To evaluate theoretically three previously published formulae that use intra-operative aphakic refractive error to calculate intraocular lens (IOL) power, not necessitating pre-operative biometry. The formulae are as follows: IOL power (D) = Aphakic refraction x 2.01 [Ianchulev et al., J. Cataract Refract. Surg.31 (2005) 1530]; IOL power (D) = Aphakic refraction x 1.75 [Mackool et al., J. Cataract Refract. Surg.32 (2006) 435]; IOL power (D) = 0.07x(2) + 1.27x + 1.22, where x = aphakic refraction [Leccisotti, Graefes Arch. Clin. Exp. Ophthalmol.246 (2008) 729]. Gaussian first order calculations were used to determine the relationship between intra-operative aphakic refractive error and the IOL power required for emmetropia in a series of schematic eyes incorporating varying corneal powers, pre-operative crystalline lens powers, axial lengths and post-operative IOL positions. The three previously published formulae, based on empirical data, were then compared in terms of IOL power errors that arose in the same schematic eye variants. An inverse relationship exists between theoretical ratio and axial length. Corneal power and initial lens power have little effect on calculated ratios, whilst final IOL position has a significant impact. None of the three empirically derived formulae are universally accurate but each is able to predict IOL power precisely in certain theoretical scenarios. The formulae derived by Ianchulev et al. and Leccisotti are most accurate for posterior IOL positions, whereas the Mackool et al. formula is most reliable when the IOL is located more anteriorly. Final IOL position was found to be the chief determinant of IOL power errors. Although the A-constants of IOLs are known and may be accurate, a variety of factors can still influence the final IOL position and lead to undesirable refractive errors. Optimum results using these novel formulae would be achieved in myopic eyes.

Anterior chamber morphometric estimation in patients they who underwent CTR implantation using Anterior Segment OCT and ultrasound biomicroscopy

Abstract Purpose To estimate anterior chamber morphometric parameters (depth and volume) in case of patients they who underwent cataract surgery with posterior intraocular lens and capsular tension ring (CTR) implantation, using Anterior Segment OCT (OCT Visante) and ultrasound biomicroscopy (UBM). Methods Studied group consisted of 23 persons 12 women and 11 men, aged from 79 to 52 years old (mean 63.9 years). BCVA ranged from 0.2 to 1.0 (mean 0.6). Anterior chamber depth and width were measured at first using Anterior Segment OCT (OCT Visante) than with the use of ultrasound biomicroscopy (UBM ). Anterior chamber volume was calculated. Results Anterior chamber depth measured using Visante OCT ranged from 4.34mm to 4.79mm ( mean 4.61 ± 0.17) and in case of UBM ranged from 4.17mm to 4.92mm ( mean 4.57 ±0.28). Anterior chamber volume measured using Visante OCT ranged from 230,42µl to 339,91µl ( mean 278,2 ± 31,32) and in case of UBM ranged from 212,75µl to 330,51µl ( mean 269,23 ±36,77). Conclusion Anterior Segment OCT is more precise in anterior chamber estimation also allows to enlarge measured area. As a non contact device is easier and faster to performe, however picture’s width in case of ultrasound biomicroscopy is larger.

A cleaning solution for silicone intraocular lenses: “sticky silicone oil”

Aim:The aim of the study was to compare the efficacy of perfluorobutylpentane (F4H5) and perfluorohexyloctane (F6H8) in dissolving silicone oil from the surface of silicone intraocular lenses (IOL).Methods:Droplets of stained...

Chirurgie combinée cataracte et affection maculaire

Cataract is frequently associated with vitreoretinal diseases. Moreover, cataract is one of the most frequent complications of pars plana vitrectomy. In cases of cataract associated with vitreoretinal diseases such as age-related macular degeneration complicated by massive submacular hemorrhage or macular hole, combined phacoemulsification and vitrectomy surgery in one session can be considered. Therefore, phacoemulsification performed before the pars plana vitrectomy for epiretinal membrane seems to be the best solution when preoperative cataract is present. In all cases, phacoemulsification with a corneal incision, insertion of a posterior capsule intraocular lens with a large diameter and a large anterior capsulorhexis are necessary.

Double capsulorhexis combined with anterior vitrectomy in congenital cataract

目的 探讨先天性白内障手术中双撕囊联合前段玻璃体切除术应用的效果.方法 对42例(44眼)儿童先天性白内障,行前后囊双撕囊、前段玻璃体切除联合人工晶状体植入术(A组);同期进行的36例(38眼)儿童先天性白内障,行前后囊双撕囊联合人工晶状体植入术作为对照组(B组);随访6～24月.结果 术后矫正视力≥0.5者,A组30眼(68.18%),B组13眼(34.21%);0.2-0.4者,A组12眼(27.27%),B组17眼(44.74%);≤0.1者,A组2眼(4.55%),B组8眼(21.05%);两组比较差异有统计学意义(x2=5.16,P＜0.05).后囊浑浊≥3级者,A组2眼(4.55%),B组8眼(21.05%);两组比较差异有统计学意义(x2=5.62,P＜0.05).均未出现眼底并发症.结论 先天性白内障术中行双撕囊联合前段玻璃体切除术,能够完全有效地止视轴区后囊的浑浊,有助于视功能的恢复。

Comparing Anterior and Posterior Piggyback IOL Power Calculations in 2-optics and 3-optics Systems

&lt;h4&gt;Comparing Anterior and Posterior Piggyback IOL Power Calculations in 2-optics and 3-optics Systems&lt;/h4&gt; &lt;p&gt;&lt;b&gt;To the Editor:&lt;/b&gt;&lt;br&gt; The classical formulas originally developed by Fyodorov et al for aphakic intraocular lenses (IOLs) or a 2-optics system have been widely used for decades without improvement. Most efforts have emphasized the accuracy and customized aspects of the estimated lens position (ELP). One of the important issues is the validity of the classical 2-optics formula used as the basis for the calculations of piggyback IOL power in phakic and pseudophakic eyes, which, strictly speaking, are 3-optics system.&lt;/p&gt;