Electron microscopic investigation of anterior lens capsule in an individual with true exfoliation

AIM: To determine the changes which occur in the anterior capsule in true exfoliation which is a very rare condition.METHODS: The anterior capsule from a 93 year-old patient and 6 other patients with age-related cataract during capsulorhexis was examined via transmission electron microscopy (TEM).RESULTS: TEM revealed apoptosis of lens epithelial cells in both two groups. Moreover, we observed lamellar delamination, granular belts in the anterior capsular zone and loss of the subcapsular epithelium cells in the posterior capsular zone, as well as abnormal fibrils located in the central capsular layer only in the sample from the patient with true exfoliation.CONCLUSION:We suggest that loss of lens epithelial cells and appearance of abnormal fibrils is important in disease developing, and our study supported age-related degeneration is one of causative factors in true exfoliation.     

Electron microscopic examination of the anterior lens capsule in a case of Alport’s syndrome

Purpose: To report a case of Alport’s syndrome and to present electronmicroscopic examination findings of the anterior lens capsule of this patient. Method: A 21‐year‐old man was referred for low visual acuity and retinal pigment epithelial changes in the left eye. The patient and his relatives underwent detailed ophthalmological examination, including electrophysiological testing. The patient also underwent electronmicroscopic examination of the anterior lens capsule. Results: His visual acuity was 6/18 OD and 6/15 OS. Anterior lenticonus and subcapsular opacities were observed in the left eye. Cataract extraction by phacoemulsification with intraocular lens implantation was performed for his poor visual performance. During the capsulorhexis, the remarkably thin and fragile anterior capsule was noted and removed. Ultrastructural analysis of the anterior lens capsule showed a thinner central zone compared with the periphery. Conclusions: The course of Alport’s syndrome can be ameliorated by early diagnosis. Therefore, the ophthalmological examination of a patient with anterior lenticonus must be combined with a detailed medical evaluation. Ultrastructural analysis of the lens capsule can support the diagnosis of Alport’s syndrome.     

Wrinkled anterior lens capsule

A 77-year-old male, a retired furniture polisher, presented for a routine eye examination. Slit lamp examination of the right eye revealed wrinkling of the anterior lens capsule, which had not changed over the past 10 years. Although capsular wrinkling has been reported following extra-capsular cataract surgery in pseudophakic patients,¹ anterior capsular wrinkling in a phakic patient is an uncommon occurrence. The causes of anterior capsular abnormalities are discussed.     

Electron microscopic study of corneal epithelial-endothelial interactions in organ culture

The interactions between rabbit corneal epithelium and endothelium were investigated in an organ culture model using scanning electron microscopy and correlative light microscopy. Following mechanical removal of corneal endothelium, corneal epithelium was observed to migrate across the cut surface of the corneal stroma and onto the denuded Descemet's membrane after 48 hours in organ culture. By 72 hours, a distinct line of contact between the migrated epithelium and endothelium was established. Following epithelial-endothelial contact, no cellular migration occurred. Corneal endothelial inhibition of epithelial migration may be a major factor in the prevention of surface epithelial invasion and proliferation following surgery and trauma.     

晶状体前囊膜的应用研究

随着移植学和组织工程学研究的推广,越来越多的研究人员已开始认识到晶状体前囊膜作为一种移植材料或支架用于治疗眼部疾病的潜能.晶状体前囊膜由Ⅳ型胶原组成,来源广、费用低、保存简便,是良好的促修复材料,它不仅能起保护、促进角膜伤口愈合的作用,而且能作为十细胞扩增支架治疗眼科多种疑难疾病,并在青光眼、视网膜黄斑变性中起到抗纤维增生和机械阻隔作用.它将成为各种内皮细胞、胚胎或成体干细胞的扩增支架应用于眼表重建、视网膜重建及角膜内皮重建等.     

Electron microscopic study of recurrent Reis-Bücklers' corneal dystrophy

We studied the cornea of a 51-year-old woman with recurrent Reis-Bücklers' dystrophy with the transmission electron microscope. The patient had had a superficial keratectomy nine years earlier. The epithelium removed in a second keratectomy contained distended endoplasmic reticulum and swollen mitochondria. The basal layer showed some cells in mitosis and a slight increase in the number of dark cells. The anterior portion of the removed stroma contained dense collagen fibrils, with the appearance of curly fibrils, which is characteristic of this disease. There were also severe degenerative changes in the stroma. These changes in the collagen fibers and alterations in keratocytes of the deeper layers were less severe than those of the superficial layer. A biopsy of the bulbar conjunctiva showed reduplication of the basement membrane.     

Herniation of the anterior lens capsule

Herniation of the anterior lens capsule is a rare abnormality in which the capsule bulges forward in the pupillary area. This herniation can be mistaken for an anterior lenticonus where both the capsule and the cortex bulge forward. The exact pathology behind this finding is still unclear. We report the clinical, ultrasound biomicroscopy (UBM) and histopathological findings of a case of herniation of the anterior lens capsule. UBM helped to differentiate this entity from anterior lenticonus. Light microscopy revealed capsular splitting suggestive of capsular delamination and collection of fluid (aqueous) in the area of herniation giving it a characteristic appearance.     

晶体前囊膜弹性的研究

目的研究前囊膜弹性。方法对２２只牛眼行连续环形撕囊术（ｃｏｎｔｉｎｕｏｕｓｃｉｒｃｕｌａｒｃａｐｓｕｌｏｒｈｅｘｉｓ，ＣＣＣ），截囊及娩核后，缓慢张大两脚规至前囊膜开口撕开后测定前囊膜的弹性。将撕裂时的周长与原切口周长之比作为前囊膜弹性指标。结果完整的ＣＣＣ切口在造成放射状撕裂之前比原切口周长扩大６１％，扩大的囊膜切口面积显著大于原切口面积及核倾斜３０°时的横断面面积。结论前囊膜具有一定的弹性，适当大小的ＣＣＣ切口可保证晶体物质的安全娩出及人工晶体的植人而不产生放射状撕裂。     

Histopathological study of the anterior lens capsule with a double-ring sign

Background A double-ring sign may be seen during continuous curvilinear anterior capsulorhexis in cataract surgery. This sign has been attributed to partial splitting of the anterior lens capsule at the continuous curvilinear anterior capsulorhexis edge. Because horizontal intracapsular splits away from the capsule edge have also been reported, a double-ring sign has been hypothesized to be a precursor to true exfoliation. We report new histopathological findings for both anterior capsule and lens epithelium changes, the latter being similar to those of true exfoliation.Methods Three anterior capsules from two patients with a double-ring sign during capsulorhexis were examined via light and transmission electron microscopy.Results Light microscopy revealed step formations in the capsule edges and surface-parallel intracapsular splits in the anterior capsules. Transmission electron microscopy revealed stratified, banded structures consisting of alternating electron-dense and -lucent granular belts (300–400 nm) at the central area of the anterior capsule, as well as vacuole-like spaces and expansion of intercellular spaces in the lens epithelium.Conclusions The thickened, stratified structure of the anterior capsule suggests abnormal lens epithelium in patients with a double-ring sign. The horizontal splits in the anterior capsule, with concomitant epithelial changes, i.e., the vacuole-like spaces and widened intercellular spaces, support the relation between a double-ring sign and true exfoliation.