前囊膜夹持人工晶状体植入术疗效观察

目的 提供一种后囊膜无功能性支撑作用时后房型人工晶状体睫状沟植入技术的改进方法。方法行角膜缘透明切口白内障超声乳化人工晶状体植入术29例(29眼)，术中采用连续环形撕囊，所有病例术中均发生非计划内后囊膜破裂，后房型人工晶状体改行睫状沟植入，光学部置于环形前囊膜下。术后随访时间3～21个月。结果全部病例术后最佳矫正视力均好于或等于0．3，术中并发症主要为后囊膜破裂(29眼)，8眼行前部玻璃体切割术，无一眼虹膜损伤。术后11眼出现一过性角膜水肿。结论对后囊膜无功能性支撑作用的病例，后房型人工晶状体借助具有连续环形开口的前囊膜夹持固定，可获得良好的视力及相对较低的并发症发生率。     

Anterior chamber and sutured posterior chamber intraocular lenses in eyes with poor capsular support

PURPOSE: To compare the clinical outcomes and complications of patients who had surgical placement of anterior chamber (AC IOLs) and sutured posterior chamber intraocular lenses (PC IOLs) after cataract surgery resulting in poor capsular support. SETTING: Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida. METHODS: A retrospective interventional comparative case series of 181 eyes of 181 patients that had implantation of an intraocular lens with inadequate capsular support was conducted. A chart review of all patients that had implantation of AC IOLs or sutured PC IOLs at a tertiary care eye hospital between 1995 and 2001 was conducted. RESULTS: Outcome measures included final best-corrected visual acuity, spherical equivalent, and postoperative complications (pseudophakic bullous keratopathy, elevated intraocular pressure [IOP] inflammation, retinal detachment, suture erosion, cystoid macular edema). Of 702 charts reviewed, 181 were found to fit inclusion and exclusion criteria. The postoperative complication risk ratio was 0.80 (95% confidence interval [CI]: 0.52-1.23) for AC IOLs compared with PC IOLs. The most common complication experienced by patients having implantation of either lens type was elevated IOP (AC IOL: 38%; PC IOL: 42%). The incidence of other complications was similar between the groups. Best-corrected visual acuity was similar; however, final spherical equivalent trended toward more myopic values in the PC IOL group (-0.82 +/- 1.67 for AC IOL versus -1.32 +/- 2.12 for PC IOL). CONCLUSIONS: The findings suggest that no significant differences in outcome exist when comparing AC IOLs to sutured PC IOLs in complicated cataract extraction with poor capsular support. Recent advances in AC IOL design have yielded lenses that provide a safe, effective alternative to sutured PC IOLs.     

Visual aberrations caused by optic components of posterior chamber intraocular lenses

A 58-year-old airline pilot had cataract surgery with implantation of a posterior chamber intraocular lens with four positioning holes around the optic edge. During periods of maximum pupil dilation, such as at night, visual aberrations including glare, monocular diplopia, and haloes occurred and he was unable to work in his occupation. The symptoms were severe enough that lens exchange was required, and a posterior chamber lens with no positioning holes was successfully implanted. The symptoms immediately subsided postoperatively and his last known visual acuity was 20/15. This case, and the report of another patient with similar postoperative problems, illustrates that implantation of lens optics with a larger effective optical zone for posterior chamber lens implantation is desirable. This is particularly true now that younger, more active patients, many still engaged in occupations, are having lens implantations.     

Anterior capsular tears and loop fixation of posterior chamber intraocular lenses

Two hundred fifty consecutive postmortem eyes containing posterior chamber intraocular lenses (PC IOLs) were analyzed according to the presence and number of radial anterior capsular tears. Over 90% of cases had been done with the "can opener" technique. A surprisingly high percentage of cases, 86%, had one to five radial tears. Furthermore, our analysis showed that the most consistent and most permanent in-the-bag fixation was achieved when only one tear or less was present in the anterior capsule. Because this study shows that the incidence of radial tears is very high after nuclear expression with "can opener" capsulectomy, it provides a scientific basis supporting the transition toward the continuous circular capsulorhexis technique that is slowly evolving. The latter technique has been shown to minimize the incidence of anterior capsular radial tears. This may ultimately serve to decrease the incidence of PC IOL decentration, an important goal if the use of bimultifocal IOLs and IOLs with small or aspheric optics is to be successful.     

Scleral and iris fixation of posterior chamber lenses in the absence of capsular support

PURPOSE OF REVIEW: To review the methods described in the literature in the past year (from August 2003 to date). RECENT FINDINGS: Techniques for scleral and iris suturing have proven safe and effective to fixate posterior chamber intraocular lenses and avoid the sight-threatening complications of anterior chamber lenses. SUMMARY: Scleral and iris fixation have both become well-established effective means for stabilizing posterior chamber lenses in the lack of adequate capsular support.     

Complications associated with posterior chamber lenses

Different types of posterior chamber lenses and their complications are discussed and compared with complications of anterior chamber lenses, pupil-supported lenses, and capsular-fixated lenses. Special emphasis is placed on the Shearing intraocular lens.     

Vaulted posterior chamber lenses and the posterior capsule

Sixty-eight patients who had extracapsular cataract surgery with intraocular lens implantation in the bag received one of two types of lenses that had been designed to create a gap between the posterior surface of the optic and the posterior capsule. Two to four months after surgery, we found that the central spacing between the posterior lens surface and the posterior capsule measured by optical pachymetry averaged 0.25 mm. The mean of the spacing for the Pharmacia LSP laser ridge was 0.25 mm (range 0.1 to 0.6) and that of the 3M LE meniscus lens was 0.24 mm (range 0 to 0.8). The amount of adherence of the posterior capsule to the posterior lens surface was less with the laser ridge design than with the meniscus lens.     

Experience with transscleral fixation of posterior chamber lenses

A total of 83 eyes with transsclerally sutured PCLs were followed for an average of 10.5 months (range 2–23 months). The vast majority of patients benefitted considerably from the procedure; 8% of cases experienced a reduction in visual acuity and 2% suffered monocular visual loss. General vascular risk factors seemed to be important in bringing about long-term complications. Patients presenting such a risk must be better identified in the future. The solution of some remaining surgical problems and questions will also add to the safety of the procedure in the future. Offprint requests to: R. Sundmacher     

Implantation of posterior chamber lenses with trans-scleral fixation

PURPOSE: The aim of this study is the presentation of our experiences in implantations of posterior chamber lenses with transscleral fixation. MATERIAL AND METHODS: The surgery was performed in 66 patients (66 eyes) using modified technique described by Lindquist et al. Primary implantations were performed in 53% subjects, in the remaining secondary implantations. RESULTS: After surgery we achieved visual acuity improvement in 80.3%, good visual acuity (0.5-1.0) in 68.4% of subjects. The main postoperative complications were: deformation of the pupil and decompensation of corneal endothelium. CONCLUSIONS: Implantation of posterior chamber lenses with transscleral fixation is preferable (alternatively for anterior chamber lenses) in young patients as well as in subjects with glaucoma, elevated intraocular pressure, iris coloboma and corneal problems.     

Anterior chamber versus posterior chamber phakic IOLs

At a time when some of the limitations of photoablation have been defined, such as worry concerning secondary ectasia, a renewed interest in phakic implantation has arisen. This is driven by the goal of avoiding correcting high ametropia with LASIK and is based on the development of soft foldable biomaterials. When all phakic IOLs are in front of the natural lens, two varieties of lenses can be distinguished, depending on whether it is located in the anterior or posterior chamber. The various models available in 2006 and those under current evaluation are reviewed. We do not report details of clinical studies that vary in cohort size and follow-up. The advantages and limitations are discussed for each type of phakic IOL. Adequate although not exclusive indications are deduced. There is no phakic lens that has proved to be superior to the others in terms of safety. All have the ability to provide a visual benefit with a gain in best corrected visual acuity. The difference is based on anatomical effects, requiring long-term follow-up in the evaluation of angles, lens, iris, and endothelium.     

Decentration of posterior chamber intraocular lenses

In a group of 300 patients with a posterior chamber lens in 19% its decentration was found, in 2.3% the iris capture syndrome. The author discusses possible causes of decentration of the implanted lens, possibilities of its therapy.     

Explantation of posterior chamber lenses.

A consecutive series of 119 explanted posterior chamber lenses is reviewed. Seventy (58.8%) were removed because of dislocation or improper fixation, 15 (12.6%) because of anisometropia, and 18 (15.1%) because of chronic inflammation. Sixty-two (52.1%) of these explantations probably occurred for reasons that can be avoided by changes in preoperative, operative, or postoperative techniques. The rate of posterior chamber lens explantations is quite low considering the large number of lenses implanted; with changing surgical techniques, we anticipate that the number of lenses requiring removal will decrease.     

Implantation of folding posterior chamber lenses

The implantation of foldable intraocular lenses (IOL) takes advantages of the benefit of small incision cataract surgery provided by phacoemulsification. However, even experienced surgeons may find the new implantation techniques required initially difficult. Advantages of small incision techniques include maintaining stability of the globe during surgery, especially in the case of acute IOP elevation caused by choroidal effusion or expulsive hemorrhage, as well as improved postoperative healing. Small incision surgery minimizes induced astigmatism, to less than 1.0 dpt change. Therefore, the patients physical and visual rehabilitation can be accelerated. Soft IOL's composed of p-HEMA or Silicone materials have been investigated for the past ten years and appear to be well biocompatible. The p-HEMA lens most often implanted is the IO-GEL, manufactured by Alcon. 120 p-HEMA IOL's were implanted in our clinic over the past 2 years. Our experiences with this foldable IOL are reported.     

Implantation of UV-absorbing posterior chamber lenses

The authors report on their experience with UV-absorbent posterior chamber IOLs (ORC) implanted between April 1, 1984 and April 1, 1985 (n = 125). Short-term complications and in particular post-operative sterile uveitis, corresponded to those in a group (n = 135) who had had regular PMMA lenses implanted. While no significant lowering of glare perception could be proved after implantation of the UV-block-lenses, color perception seemed to be more correct with these lenses. Because of the short observation time no significant statements can be made regarding the frequency of cystoid macular edema.     

Refraction after cataract surgery with posterior chamber lenses

In an attempt to determine the accuracy of ultrasound biometry, the spherical equivalent of the refraction obtained after ECCE and implantation of a posterior chamber IOL in 1663 patients was compared to the desired refraction determined prior to surgery. Follow up time was 21 months on the average. In only 7.4% of the eyes was the exact predetermined value obtained. In 44.3% it differed toward plus and in 46.6% toward minus. The predetermined value +/- 1 dpt was obtained in 63.8% and +/- 2 dpt in 88.3% of the cases. In 11.7% of the eyes, the desired value was missed by more than +/- 2 dpt.