Epikeratophakia for Myopia Correction

Epikeratophakia is based on the principles of the Barraquer refractive procedures, with modifications that simplify the surgical technique and eliminate the use of the microkeratome by placing the donor corneal tissue lens on the anterior surface of the cornea. Procedures developed to permit freeze-drying the preshaped lens for storage enable these lenses to be obtained from a central source, freeing the surgeon from the complexities of the computer and the cryolathe. The correction of theoretically unlimited amounts of myopia is possible with these lenses. In 12 eyes that underwent the final epikeratophakia procedure, the average desired correction achieved was 98%.     

Epikeratophakia—The Surgical Correction of Aphakia: Update 1981

Epikeratophakia grafts used to rehabilitate vision in adult monocular aphakic patients intolerant of contact lens correction or not candidates for IOLs were studied prospectively. Thirty-two patients who entered this study between its inception in February 1980 through February 1981 were followed for at least eight months. Patients with normal visual potential before surgery had average visual acuities with spectacle overcorrection of 20/50 at four months, 20/40 at eight months, and 20/30 at one year. Few long-term complications were seen. Empirical modification of the lathing process has decreased the undercorrection from the 5.5 diopters seen in the early patients to the 1.0 diopter seen in the more recent patients. Problems with predictability are related to the behavior of preserved corneal tissue during the lathing and the healing of these lamellar grafts. This procedure is intended for aphakic patients for whom IOL and contact lens correction is not possible.     

异种表层角膜镜术的实验研究

在猴-猴表层板层角膜移植术成功的基础上,进行了三例人-猴异种表层角膜镜片术。术眼均获透明愈合。观察期分別为1个月、3个月和2年。对3例表层角膜镜片术的术眼角膜进行了组织学检查,发现上皮厚度及基质角膜细胞正常,进行异种表层角膜镜片术必须根据以下三个因素:供受体组织结构和屈光参数相近;供体角膜要有前弹力膜和一定的厚度。另外,对手术方法也进行了某些改进。     

A Prospective Study of the Use of Hyperopic Epikeratophakia Grafts for the Correction of Aphakia in Adults

The results of a prospective clinical study of hyperopic epikeratophakia grafts for the visual rehabilitation of aphakic patients are presented. Visual acuity data are given for 21 aphakic patients who have been followed for up to six months postoperatively. With spectacle overrefraction, on the average, patients were within three lines of their preoperative potential vision at three months postoperative and within two lines at six months postoperative. Three months postoperatively, two patients achieved visual acuities of 20/20, and 57% had 20/40 or better with spectacle overcorrection. Six months postoperatively, three patients achieved best-corrected visual acuities of 20/20, and 80% had best-corrected visual acuities of 20/40 or better.     

The Preliminary Report of Epikeratophakia in the Treatment of Pediatric Aphakia after Traumatic Cataract Extraction

Purpose: To study the role of epikeratophakia in treating pediatric unilateral aphakia after traumatic cataract extraction.Methods: We performed epikeratophakia in 43 children to treat aphakia after traumatic cataract extraction, using the corneal lenses made by ourselves. The rehabilitation of the the postoperative vision and the prevention of amblyopia were observed with a mean follow-up period of 20 months.Results: All the lenses remained transparent. Postoperatively, 31 cases (72. 1%) achieved uncorrected visual acuities (V. A) over 0. 2, 32 cases (74. 4%) achieved corrected V. A over 0. 4. Most of the cases achieved the best preoperative corrected V. A with spectacles of less than 3 diopters. No severe complication occurred. Conclusion: Epikeratophakia is predictable with quality lens and correct surgical technique. The result suggests that the epikeratophakia is one of the best treatment for the pediatric aphakia especially for those who are not optimal for IOL implantation. Eye Science 1997 ;13:3     

表面角膜镜片术治疗小儿外伤性白内障术后无晶体眼的初步报告

用自制的同种材料的表面角膜镜片，对４３例（４３只眼）小儿外伤性白内障术后无晶体眼施行手术治疗，追踪时间平均２０个月，结果全部镜片透明愈合。有３１例（７２．１％）术后裸眼视力达０．２以上，３２例（７４．４％）矫正视力达０．４以上。大部分病例加载３Ｄ以下的眼镜可达术前的矫正视力，无严重并发症。表明：表面角膜镜片术是治疗小儿外伤性白内障术后无晶体眼的最好办法之一，尤其适用于不能装人工晶体的病例。     

少年儿童眼外伤术后无晶体眼的接触镜矫正

目的探讨少年儿童单眼外伤术后无晶状体眼的接触镜(CL)矫正方法和临床效果.方法观察81名少年儿童眼外伤术后患者的眼部改变,并根据其屈光状态的变化、对侧眼的状态及其生活的实际需要,选择验配了软性接触镜(SCL)、托力克软性接触镜(TSCL)、透气性硬性接触镜(RGPCL)、加虹膜色彩的非透气性硬性接触镜(PMMA虹彩片)和软、硬组合型镜片系统(Piggyback CL),并比较视力矫正效果.结果与对侧健眼比较,外伤术后眼角膜曲率半径值显著改变,角膜散光度明显增加.52眼选用SCL和TSCL,矫正视力与框架眼镜比较无明显差异;22眼选用RGPCL,4眼选用PMMA虹彩镜,3眼选用Piggyback CL,三种镜片矫正视力比框架眼镜明显提高.PMMA虹彩镜和Piggyback CL用于外伤后角膜白斑、术后无晶状体、虹膜严重损伤眼,除显著提高视力外,还明显改善了羞明症状和眼外观.结论在严格的医疗化管理下,利用CL矫正少儿眼外伤术后无晶状体眼的高度屈光不正、屈光参差,恢复双眼视觉是安全、有效的.硬性接触镜(HCL)的视力矫正效果明显优于SCL.     

Update on Keratophakia

Visual results are reported for 23 cases of keratophakia for the correction of surgical aphakia followed from 12 to 48 months. Seventeen of the 23 patients had final visual acuities of 20/40 or better. The average residual visual overrefraction was 1.87 ± 1.79 diopters (mean ± SE), with an increase of postoperative astigmatism of 1.70 ± 1.33 diopters. Complications included interface deposits and peripheral epithelial deposits that did not interfere with vision. One patient had an anterior chamber penetration and subsequent penetrating keratoplasty, and two patients had lenticules removed because of corneal edema secondary to increased intraocular pressure. The major disadvantages of keratophakia are the complexity of the procedure and the time required (4 to 6 months) to achieve best-corrected spectacle visual acuity. However, because this procedure is extraocular, it is a better choice than secondary intraocular lens implantation for patients who are unilaterally aphakic and for the young patient.     

用角膜接触镜制造车床切削表面角膜镜

介绍了英国具有半径旋转功能的ＰＡＬｕｎｉｖｒｓａｌ型角膜接触镜精密车床所设计的冷冻装置。此装置基部与车床夹头相匹配，冻盘直径０．９ｍｍ，凹面曲率８ｍｍ，以液氮气体为制冷源，将供体角膜冻贴于装置上进行切削。包括供体角膜的预备和应用公式的选择，以及车床切削半径的确定以制作表面角膜镜片。     

无晶状体眼41例手术矫治疗效评价

目的:探讨41例无晶状体眼手术矫治疗效及安全性。方法:选取2004/2009年我院无晶状体眼患者41例。每例患者均进行了二期后房型人工晶状体植入手术,观察其矫治情况及安全性(随访6mo)。结果:患者41例植入后房型二期人工晶状体均取得了较好的矫正效果。结论:二期后房型人工晶状体植入手术矫治后囊破裂或缺如的无晶状体眼是有效、安全可行的方法。手术效果取决于患眼条件,与术前矫正视力有明显正相关。手术无严重并发症发生。     

无晶状体眼屈光矫治方法的概述

无晶状体眼的屈光矫治方法包括框架眼镜矫正、角膜接触镜矫正和人工晶状体(IOL)植入术.框架眼镜矫正物像放大率高,视野受限,婴幼儿无晶状体眼因眼球尚处在发育阶段致无法植入人工晶状体而多选用框架眼镜矫正.角膜接触镜物像放大率低,分为软性角膜接触镜和硬性角膜接触镜,前者因透氧性差易致眼表病变故应用较少,后者透氧性强,尤适合于眼外伤所致不规则散光者或虹膜缺失者.目前临床上最常用的还是人工晶状体植入术,植入人工晶状体的眼更符合生理解剖结构,可以尽量避免屈光参差、像差等不足.根据人工晶状体的植入位置共分为前房型人工晶状体植入术和后房型人工晶状体植入术,前房型人工晶状体植入术又分为房角固定型人工晶状体植入术和虹膜固定型人工晶状体植入术,后房型人工晶状体植入术分为Ⅱ期囊袋内人工晶状体植入术、睫状沟人工晶状体植入术和经巩膜缝线式人工晶状体植入术.     

Spectacle correction for aphakia. The prismatic effect

Because spectacle lenses are fixed in position relative to the eyes, the visual axes during convergence pass nasal to the optical centers, and create a prismatic effect. The eye rotates less than 15° before the head is turned; therefore for central vision, only an area of the lens about 13 mm wide is used. A reading addition of +6.00 D is probably the maximal power bifocal addition that can be prescribed for comfortable binocular vision in a high plus correction. The distance correction produces a base-out effect of at least 4^Δ for each eye at the reading distance, even though the bifocal segments are adequately decentered.     

表层角膜镜片术治疗圆锥角膜

采用表层角膜镜片术联合前房穿刺，手术治疗18例21眼圆锥角膜患者，经术后3个月～1年8个月的随访，患者的视力、矫正视力明显提高，角膜屈光力显著降低，平均为45．83D。认为对确诊为圆锥角膜但尚无后弹力层破裂，或中央视区尚未形成瘢痕的患者，应早期行该术治疗，术后疗效确切，作用持久，稳定。     

近视眼手术矫治的临床进展

本文就矫治近视的准分子激光角膜屈光手术、晶状体性屈光手术及如何制定个性化屈光手术方案等临床进展作一综述。     

Surgical management of chronic glaucoma in aphakia

The surgical management of glaucoma in aphakia has been limited by poor success in the control of intraocular pressure and serious postoperative complications that threaten vision. A consecutive series of trabeculectomy filtering procedures in aphakic eyes with a mean preoperative intraocular pressure of 38 mmHg was followed for an average of 26 months and revealed a 62% control of intraocular pressure at 21 mmHg or less. Five additional patients (24%) had pressures lower than 21 mmHg following digital massage. The complication of decreased visual acuity following surgery was significant but not directly related to the surgical procedure. Another patient population with glaucoma and aphakia with a mean preoperative pressure of 25 mmHg was treated with laser trabeculoplasty. In 12 of 15 patients (80%) intraocular pressure was lower than 22 mmHg for an average of eight months and did not require glaucoma surgery. There were no significant complications following this therapy and all patients retained preoperative level of visual acuity. In aphakic patients who have uncontrolled glaucoma on maximal medical therapy, surgery is indicated. We recommend the following approach to surgical management: (1) Laser treatment to the trabecular meshwork if the angle is open; (2) if this fails, or the angle is extensively closed, a trabeculectomy filtering procedure is suggested; (3) cyclocryotherapy has been effective in controlling pressure but the unpredictable loss of vision has prompted caution in seeing eyes; (4) cyclodialysis; and (5) transpupillary or transscleral treatment of the ciliary processes are additional modes of therapy. Improved results of surgical treatment for glaucoma and aphakia have been encouraging and should be used when maximal medical therapy is ineffective.     

Paediatric aphakic epikeratoplasty: early Australian experience

Epikeratoplasty has been performed on eight eyes of seven patients by one surgeon in Melbourne since March 1988. All cases were contact lens or spectacle intolerant. Standard surgical techniques utilising donor lenticules imported from the United States and including an annular keratectomy were employed for the procedure. An eight-month followup is availabe for the first two cases, aged two and 10 years. The elder of these children has achieved corrected acuity of 6/9 in each eye. Refractive and early visual acuity results are presented for the five other cases which have at least two months of followup. The results indicate that in appropriately selected patients, epikeratoplasty offers a safe, effective modality for visual restoration and development in otherwise untreatable aphakic children.     

Clinical Results of Keratophakia and Keratomileusis

Thirteen keratophakia patients were followed for 13 to 35 months. Eighteen cases of hyperopic keratomileusis or hyperopic keratomileusis using preserved corneal tissue were followed for 2 to 30 months. All 13 patients who underwent keratophakia achieved 20/50 or better acuity. All seven patients having hyperopic keratomileusis achieved 20/60 or better acuity. Eight of the 11 patiens who had hyperopic keratomileusis using donor corneal tissue achieved 20/60 or better acuity. The preservation of lenticules after lathing did not adversely affect the correlation between predicted and observed dioptric corrections. There was a statistically significant correlation between predicted and observed dioptric correction measured at the corneal surface when the lenticule was lathed from fresh tissue (hyperopic keratomileusis) or from relatively fresh tissue (keratophakia). However, we found that there was poor correlation between the predicted and observed corrections when the lenticule was lathed from donor tissue that had been cryopreserved for long periods of time (hyperopic keratomileusis with preserved corneal tissue).     

Keratophaki Update

Since October 1977, the authors have attempted 32 keratophakias (refractive corneal surgery using an interlamellar homograft disc). Twenty-nine of these were primary and three secondary on aphakic eyes. These cases were divided into two series. In the first series, the dioptric correction was 28.5% less than the amount calculated to correct the aphakic error. In the second series, only 6.5% of the calculated dioptric power remained uncorrected. Keratophakia is an alternative to other modalities of secondary full-time correction of aphakia since the internal eye is not compromised by this secondary procedure as it is with a secondary intraocular implant. Further improvements in instrumentation techniques and mathematic programs will broaden the application of refractive keratoplasty techniques.