Epikeratophakia for keratoconus in mentally retarded patients. The use of fresh, free-hand made lamellar grafts.

Epikeratophakia for keratoconus was done in 11 mentally retarded patients, using fresh, free-hand made lamellar grafts. The mean follow-up period was 31.5 months. The grafts remained clear and well adapted in 7 cases (63.6%). Necrosis of the lower part of the graft occurred in 3 eyes (27.3%), and was probably caused by persisting epithelial defects. Only one of these grafts had to be removed. Despite concurrent eye diseases, such as cataract and possible amblyopia, an improved overall visual function was reported in 5 of the 11 patients (45.5%). No vision-threatening complications related to the epikeratophakia surgery was found.     

Corneal cross linking for keratoconus

Riboflavin-induced ultraviolet light (UV) cross linking has received a significant amount of attention in recent years. It is currently approved in Europe as a treatment for keratoconus and is also being used for other corneal disorders. The goal of this paper is to review in detail seminal papers and studies that have been done to support cross linking as a safe and effective treatment for patients with early stages of keratoconus.     

Corneal topography of posterior keratoconus.

Posterior keratoconus is an unusual abnormality of the cornea generally classified as one of the anterior chamber cleavage anomalies. It is characterized clinically by the presence of a circumscribed or generalized corneal thinning with posterior depression of the cornea and is considered distinct from keratoconus. Although patients with posterior keratoconus may have visual complaints clearly related to their abnormal corneas, the surface topography of these corneas has not been studied in detail. Keratometry and photokeratoscopy provide an incomplete picture of the surface geometry of posterior keratoconus. We utilized computer assisted topographic analysis to study the cornea of a patient with posterior keratoconus. The Topographic Modeling System demonstrated that the patient's cornea showed a central steepened "cone" coincident with the area of circumscribed posterior keratoconus as well as paracentral flattening. This report documents the topographic abnormality in this rare disorder.     

Corneal dystrophies and keratoconus

This year's reports have given us a better understanding of several dystrophies as well as improvements in diagnosis and treatment. Eight corneal dystrophies have now been mapped to specific chromosomes and of these lattice, granular, Avellino, and Reis Bückler's dystrophies map to the same region of chromosome 5q, raising the question whether they are the result of mutations in separate genes or of mutations within alleles of a single gene. Phototherapeutic keratoplasty appears to offer an advantage in the initial treatment of several dystrophies whose symptoms arise from superficial corneal change. Some success has been reported in reducing the degree of hyperopic shift that accompanies deeper ablations. Further support for the genetic basis of keratoconus comes from a study in monozygotic twins and from improvements in quantitative videokeratographic indices, which have also improved our ability to distinguish keratoconus from other topographic abnormalities of the cornea. A new hypothesis for the mechanism of keratoconus proposes that an increased expression of interleukin-1 receptors, acting through a paracrine pathway, may disturb keratocyte activity and turnover, leading to a loss of stromal mass.     

Corneal dystrophies and keratoconus

Knowledge about keratoconus (KC) and the corneal dystrophies continues to advance at a steady pace in view of the wide interest in these topics to basic scientists and clinical ophthalmologists. As in the past the articles on KC outnumber those on all of the other corneal dystrophies combined. Major advances have been made mainly regarding several specific corneal dystrophies, but KC remains a perplexing disorder with many unanswered questions. As we learn more and more about the corneal dystrophies from genetic linkage analyses and molecular biological techniques it will eventually be possible to understand the fundamental defect that causes these conditions.     

Corneal topography of keratoconus

Sixty-three eyes of 49 patients with keratoconus were studied by means of computer-assisted corneal topographic analysis. Two patients with keratoconus in one eye had no topographic evidence of keratoconus in the opposite eye. Keratoconic topographic alterations were classified into two groups. The majority of the patients (72%) had peripheral cones, with steepening extending to the limbus. In this group, the steepening was commonly restricted to one or two quadrants. In some cases, however, the changes involved nearly the entire corneal surface. The remaining group (about one quarter of the keratoconus patients) had steepening that was restricted to the central cornea. In either group, the topographic alterations in the two eyes of any single patient were characterized by a high degree of nonsuperimposable mirror-image symmetry (enantiomorphism). In the majority of patients, however, there was a large and statistically significant disparity between the two eyes in the power at the apex of the cone and the total cylinder [mean differences 8.2 +/- 6.0 D (p less than 0.0001) and 4.3 +/- 2.7 D (p less than 0.0001), respectively].     

Corneal topographic changes in healthy siblings of patients with keratoconus

AIM: To describe the involvement in relatives of keratoconus (KCN) patients with corneal topography map. · METHODS: A total of 150 siblings of 300 eyes of 75 KCN patients referred to corneal clinic were studied and experienced complete slit-lamp, refraction examinations and topographic cornea maps provided by videophotoker- atography. ANOVA, Fisher exact and Chi-square tests performed to compare of results. · RESULTS: Of 150 siblings, 56% were female and 44% were male with average age of 21 (range 15-39) years. KCN and suspect KCN diagnosed in 12.3% and 6.6% respectively. The central keratometry (CK) was 46.5±4.51 dioptr (D) in KCN and 45.66±1.52D in suspect KCN. Inferior-superior value (I-S) was 3.51±2.5D in KCN and 1.56±1.22D in suspect KCN. In KCN condition the oval pattern was 67.6% (n = 25) and Round pattern detected 32.4% (n =12). In suspect KCN these patterns detected 90% and 10% respectively. Refractive errors in KCN were -7.5 to +1.25 dioptr (-1.25±1.83), in suspect KCN 0.45 to -4.2 dioptr (-0.68±0.76) and in healthy group 2.75 to -7.5 dioptr (-0.6±1.12). Astigmatism was mild in 22.7%, moderate and sever astigmatism in 18.3% in KCN and suspect KCN · CONCLUSION: Increasing KCN condition in healthy siblings of KCN patients shows require to screening plan to early diagnose and cautionly treatment of contact lens in these individuals.     

圆锥角膜患者健康同胞的角膜地形图变化

目的:描述圆锥角膜(KCN)患者亲属的受累角膜地形图。方法:对75名KCN患者的150名同胞的300只眼睛在角膜诊所进行了研究,经过完整的裂隙灯,屈光检查并由角膜摄影视频图片提供角膜地形图。进行方差分析,Fisher精确测试和卡方检验比较结果。结果:在150个同胞中,女56%,男44%,平均年龄21(15-39)岁。诊断KCN和可疑KCN的分别为12.3%和6.6%。KCN患者中央角膜曲率(CK)为46.50±4.51(D)而可疑KCN患者为45.66±1.52(D)。KCN患者角膜下方与上方平均屈光度差值(I-S)为3.51±2.50(D)而在可疑KCN患者为1.56±1.22(D)。在KCN状态椭圆型为67.6%(25例)而圆型为32.4%(12例)。在可疑KCN分别为90%和10%。KCN屈光不正为-7.50至1.25(-1.25±1.83)D,可疑KCN为0.45至-4.2(-0.68±0.76)D而健康组为2.75至-7.5(-0.6±1.12)D。KCN和可疑KCN中22.7%为轻度散光,18.3%为中度散光。结论:KCN患者健康同胞中KCN情况增加显示出需要筛选检查以早期诊断并在这些个体中谨慎实施屈光性角膜手术或隐形眼镜治疗。     

Blindness in mentally retarded children

A preliminary survey of the causes of blindness in mentally retarded children in Denmark showed that 50% of the children had optic atrophy, 12.5% had cataract while tapeto-retinal degenerations, other malformation and retrolental fibroplasia each represents 8-9% of the causes of blindness. The survey, was done through written notification and some patients with tapeto-retinal degenerations might have been wrongly diagnosed.     

Blindness in mentally retarded children

A preliminary survey of the causes of blindness in mentally retarded children in Denmark showed that 50% of the children had optic atrophy, 12.5% had cataract while tapeto-retinal degenerations, other malformations and retrolental fibroplasia each represents 8–9% of the causes of blindness. The survey, was done through written notification and some patients with tapeto-retinal degenerations might have been wrongly diagnosed.     

Corneal collagen cross-linking in keratoconus management

Functional results of collagen UV cross-linking in keratoconus management are evaluated. 77 patients (87 eyes) with keratoconus stage I-II (Amsler classification) were under observation. All the patients received UV radiation (370 3m, 3mW/sm2) for 30 min with simultaneous instillation of "Dextralink" solution. Besides routine ophthalmological examination confocal biomicroscopy (HRT III, Heidelberg, Germany) and optical coherent tomography (Vizante-OCT, Carl Zeis, Germany) were performed before, in 1, 3, 6 and 12 months, 2 and 3 years after the procedure. By the 6th month the best corrected visual acuity showed improvement from 0.41 + 0.12 (M+m) till 0.52 + 0.01. Corneal refractive power decreased to 49.41 + 1.69 dpt by the last examination. UV cross-linking is a minimally invasive and effective option for management of keratoconus at the early stages, that let achieve biomechanical stabilization of the cornea and reduce progression rate.     

圆锥角膜的角膜前后表面形态及厚度检测

目的　了解圆锥角膜的角膜地形图改变。方法　应用Orbscan角膜地形图系统检测 35例 (47只眼 )圆锥角膜患者的角膜 ,对其角膜中心点、锥顶、角膜后表面最高点、角膜屈光度最大点和角膜最薄点的位置、角膜前表面高度、角膜屈光度及角膜厚度 ,以及角膜屈光度和角膜前表面高度的关系进行分析。结果　圆锥角膜锥顶的高度平均为 (0 10 2± 0 0 4 4 )mm ,距角膜中心点的距离为(0 6 86± 0 376 )mm。圆锥角膜锥顶、角膜后表面最高点和角膜屈光度最大点的位置分布以颞下最多 ,其他依次为鼻下、颞上、鼻上 ,最薄点以鼻下方为多 ,其次为颞下。圆锥角膜的角膜曲率为 (6 0 9± 10 4 / 5 3 4± 8 7)D ,角膜中央直径 3mm、5mm内平均屈光度数分别为 (5 7 1± 8 0 )D、(5 0 7± 5 4 )D。圆锥角膜锥顶的高度与此点的屈光度数呈明显的正相关 (r=0 6 97,P <0 0 1) ,与此点的角膜厚度呈负相关 (r=- 0 5 6 3,P <0 0 1)。结论　Orbscan角膜地形图系统可为早期诊断圆锥角膜并提供形态学依据。     

Corneal sensitivity and topogometry in keratoconus

Paracentral corneal topography was determined (with a topogometer) and corneal sensitivity was measured in 90 keratoconic eyes. Sensitivity was evaluated in a control group and found to be greater in all five sectors than the sensitivity found in keratoconus patients. The zone of marked corneal steepening was located infero-temporally in 59% of our patients, although steepening was found in other zones as well. Overall, sensitivity was greatest in the temporal cornea and lowest in the inferior cornea, this hypoesthesia coinciding with the area of pronounced corneal protrusion. Corneal sensitivity, which was diminished in contact lens wearers, recovered within 7 days after discontinuing contact lens wear.     

圆锥角膜早期的角膜地形图改变

目的　揭示早期圆锥角膜角膜地形图的特征,为早期诊断此病提供参考。方法　收集了本院门诊拟诊为早期圆锥角膜的患者27例52眼。所有患者均行TMS-1角膜地形图测定。结果　80.77%眼角膜最高屈光度部位在正下方或颞下方,最高屈光度在45D以上,散光在2D以上,所有眼平均最高屈光度在47.56D±5.80D,平均散光5.47D±3.80D;角膜非对称性指数(SAI)及角膜规则性指数(SRI)值大于0.5者分别为94%、98%,SAI值平均为2.6±1.9,SRI值平均为1.67±0.94。结论　早期圆锥角膜的测定须兼顾上述综合参数,SAI及SRI值的变化更敏感。     

Corneal amyloidosis associated with keratoconus

Nodular, gray-white, central corneal opacities which extended from the subepithelial zone through the anterior four fifths of the stroma developed in a 50-year-old man with a longstanding history of hard contact lens wear for keratoconus. Results of histopathologic analysis of the corneal button obtained at the time of penetrating keratoplasty disclosed that the opacities were composed of amyloid. Corneal amyloidosis is rarely found in association with keratoconus. Although there were some similarities in the pattern of amyloid deposition to that seen in primary familial amyloidosis of the cornea, the authors believe that their patient is more likely to have had a secondary amyloidosis. Corneal amyloidosis should be considered in keratoconus patients with development of unusual forms of central corneal opacification.