Scleral reinforcement: two case reports

We report two cases of unilateral scleral reinforcement undergone for progressive pathologic myopia. Examination ten years after the operations showed the supportive effect of the scleral grafts. The effect, however, was localized and did not appear to block the overall progression of posterior staphyloma formation significantly.     

Scleral reinforcement in rabbits using synthetic graft materials

Because of disappointing results using homologous collagen for scleral reinforcement in the treatment of pathologic myopia in humans, we undertook a series of experiments in rabbits to test the mechanical properties and long-term biocompatibility of three different synthetic graft materials. Grafts made from two of these materials, Gore-Tex Soft Tissue Patch (expanded polytetrafluoroethylene) and Miragel (poly[methyl acrylate-co-hydroxy-ethyl acrylate]), were easy to position about the globe. Both materials, however, were resistant to invasion by fibrovascular tissue. The third material, woven Dacron (polyethylene terephthalate), though more difficult to position, permitted extensive invasion of fibrovascular tissue, which made all parts of the graft firmly adherent to the globe. Our results indicate the long-term compatibility of all three of these materials when used as periscleral grafts in rabbits. However, our results also suggest that a woven material such as commercially available Dacron is a more suitable graft material for scleral reinforcement in humans than collagen, Miragel, or Gore-Tex.     

A new intraocular lens formula for high myopia

We developed a formula suitable for calculating intraocular lens power for eyes with axial lengths of 27 mm or greater. We then used this formula in a prospective study to determine its reliability in 32 eyes. In these latter cases the mean error between predictive postoperative refraction and actual postoperative refraction was 0.36 D, with 67% of the cases having less than 1.0 D error; 84% of the cases having less than a 2.0 D error; and no cases having an error greater than 3.0 D. The new formula provided greater accuracy for these highly myopic eyes than the SRK, SRKII, Hollady, and Thompson formulas.     

Errors in IOL power calculations for axial high myopia

We studied 115 eyes with axial lengths of 27 mm or more after implantation of a posterior chamber intraocular lens in order to determine discrepancies between the predicted refractions and the actual postoperative refractions. We then reviewed the three major variables used to predict refractions in these eyes--corneal curvature, anterior chamber depth, and axial length measurements--in an attempt to determine whether any of these variables were correlated with the discrepancies. We found that the main reason for postoperative refractive error was inaccurate measurements of preoperative axial length.     

The correction of high myopia.

There are welcome signs that the ophthalmic profession is at long last facing up to its responsibilities to those unfortunate enough to suffer from high myopia. At this time, it is my opinion that the safest and most effective option is the use of the ZB5M anterior chamber implant inserted into phakic eyes, the updated technique devised by Baikoff and Domilens. In the long term, the future probably lies with the use of corneal inlays using a high refractive index thermoplastic such as polysulfone.     

Scleral fixation for intraocular lenses

Four methods for scleral fixation of intraocular lenses are described and 303 lenses fixated by one of these methods during three years are reviewed.     

Scleral show

Scleral show is an anatomical condition in which the sclera area is visibly exaggerated due to constitutional, evolutive, or endocrine etiology. It can also occur because of iatrogenies, and is considered one of the most complex blepharoplasty complications. Its evolution and poor response to treatment are questionable. The defect is not always linked to an ectropion, and the basic differences between the two are explained. During blepharoplasties, in order to avoid iatrogenic scleral show, among other complications, one should take special precautions with the quantity and the exact location of the tarsal portion of orbicularis oculi muscle to be resected.     

有晶状体眼后房型人工晶状体植入矫正高度近视的临床观察

目的探讨有晶状体眼后房型人工晶状体植入术矫正高度近视的有效性和安全性。方法后房型人工晶状体植入治疗高度近视眼患者8例15眼,术后随访分别检查裸眼视力、矫正视力、眼压、角膜及前房情况,UBM观察人工晶体位置。结果 15眼均顺利完成手术,术后视力均达到或超过术前最好矫正视力。术后眼压及人工晶体位置正常,术后1周内有2眼出现人工晶体表面少量色索。随访1年,视力稳定,未出现晶体混浊及眼压升高等严重并发症。结论有晶体眼后房型人工晶体植入治疗高度近视,视力恢复迅速,未发生严重并发症,预测性好,具有安全性和有效性。     

Scleral patch for exposed silicone buckles.

A technique using preserved sclera to patch exposed retinal silicone is described. Permanent silicone buckles may be preferred in certain cases. If cultures are negative, a rectangular piece of preserved sclera, full or half thickness, is sutured to an anteriorly dissected scleral flap and directed posteriorly over the previously exposed silicone. Tenon's and conjunctiva are sutured over the scleral homograft.     

Delayed regression of effect in myopic epikeratophakia vs myopic keratomileusis for high myopia

We compared the effectiveness and stability of our first six consecutive myopic epikeratophakia procedures (mean follow-up 18 months, range 14 to 26) with our first four consecutive cryolathe myopic keratomileusis procedures (mean follow-up 28 months, range 14 to 35). Myopic keratomileusis reduced preoperative myopia (range -8.9 to -12.1 diopters) by 77% to 94% in four patients. Refraction and visual acuity remained stable for over 1 to 3 years. In contrast, only three of the six myopic epikeratophakia procedures had stable results. The remaining three eyes which were within 0.38 D of emmetropia at the time of suture removal showed a loss of effect, resulting in myopia worse than their preoperative values in two eyes and a small correction in one eye. Only one of the six eyes achieved an uncorrected visual acuity better than 20/200. We conclude that myopic keratomileusis may be the procedure of choice for treating individuals with myopia of -8 to -15 D, because the incidence of late regression of effect after myopic epikeratophakia using the techniques in this study is unacceptable.     

Combined surgical procedure for the prevention of blindness caused by progressive high myopia

A combined prophylactic procedure consisting of the strengthening of the sclera by fascia lata implants and the laser photocoagulation of peripheral retinal degenerations has been developed for the prevention of blindness caused by progressive high myopia. More than 7 years of experience gained with over 400 patients showed that none of the treated eyes developed retinal detachment or other severe complications of high myopia. Moreover, the degree of myopia decreased by a mean value of 3.0 D in 90%, and the visual acuity improved by a mean value of 0.15 in 70% of the patients treated. The authors suggest that their combined prophylactic procedure should be tried out and introduced to general ophthalmological practice.     

薄角膜瓣Lasik分区切削治疗高度近视的临床探讨

目的:评价薄角膜瓣下应用分区切削模式进行lasik治疗高度近视的临床效果.方法:对118例(220眼)高度近视患者因选择常规切削剩余角膜厚度小于250um,而进行薄瓣下分区切削治疗,分2～3区切削,切削光区4.5～6.0mm,随访观察6月～48月,观察术前后的裸眼视力,矫正视力,屈光状态及并发症的发生情况.结果:薄瓣Lasik分区切削术后反应轻,裸眼视力恢复快,术后第一天裸眼视力即明显提高,术后6月裸眼视力在1.0以上者有197眼占89.5%,0.5～0.8者22眼占10%,小于0.5者1眼占0.5%,屈光度稳定在士1.00D以下者191眼占86.8%.主要并发症为角膜瓣细微皱褶,少数患者出现眩光.夜视力下降,一月后减轻或消失.结论:薄瓣准分子激光原位角膜磨镶术分区切削模式治疗角膜相对较薄的高度近视患者,可节省角膜组织,具有安全可靠,稳定性、可预测性强的临床效果.     

Scleral fixation suture for dislocated posterior chamber intraocular lens

The posterior dislocation of an intraocular lens is a serious complication of extracapsular cataract extraction with implantation of a posterior chamber intraocular lens. We describe a method of repositioning and suturing such a lens, using pars plana techniques. The method we recommend has several advantages over previously described methods, including the use of radially oriented scleral fixation sutures.     

超声乳化术对高度近视合并白内障患者视觉质量的影响

目的以小切口手法碎核术对比分析超声乳化术对高度近视合并白内障患者视觉质量的影响,以探讨其临床应用价值。方法选取本院收治的高度近视合并白内障单眼病变患者72例,以随机数字表分为观察组和对照组各36例;对照组采用小切口手法碎核术和人工晶状体植入术进行治疗,观察组采用超声乳化术和人工晶状体植入术进行治疗。根据患者个体情况随访6-12个月,记录最佳矫正视力和并发症发生情况;并分别于治疗后1周、3个月及6个月常规检查术源性散光、屈光状态、中央角膜厚度（CCT）、角膜细胞计数（CEC）、角膜敏感度及黄斑中心凹视网膜厚度（CMT）。结果术前,两组患者的BCVA无统计学差异（P〉0.05）;术后,两组患者BCVA均有显著改善（P〈0.001）,且观察组明显优于对照组（P〈0.05）。术前,两组患者的各项角膜、黄斑区及相关光学指标无统计学差异（P〉0.05）;术后,观察组各时间段的术源性散光度和CMT显著小于对照组（P〈0.001）,角膜敏感度显著优于对照组（P〈0.001）。此外,观察组的角膜水肿发生率显著低于对照组（P〈0.05）,但总并发症发生率无统计学差异（P〉0.05）。结论超声乳化术相对封闭的操作环境能够维持前房稳定性,利于保护角膜神经,提高高度近视合并白内障患者的术后视觉质量。