ATPase pump site density in human dysfunctional corneal endothelium

Proper corneal hydration is maintained by a Na, K-ATPase pump located in the lateral membranes of the endothelial cells. In dysfunctional corneas this pumping action appears to break down as the corneas become edematous. In order to provide quantitative and qualitative data on the Na, K-ATPase pump site density on dysfunctional and functional human corneal endothelial cells, the present study has employed both autoradiographic and histochemical techniques. Computer-assisted morphometrics and statistical analysis showed that there was a significant reduction (P less than 0.001) in 3H-ouabain binding, and thus ATPase pump sites, in the three types of corneas (Fuchs' endothelial dystrophy, aphakic and pseudophakic bullous keratopathy) with dysfunctional endothelia as compared to both types of corneas (eye bank, keratoconus) with functional endothelial cells. There were no significant differences amongst the dysfunctional types or between the two functional types of corneal endothelial cells in respect to density of silver grains. Histochemical staining for ATPase showed less p-nitro-phenylphosphatase histochemical reaction product present on dysfunctional endothelial lateral membranes than in the functional cells.

Endothelial viral inclusions in Fuchs' corneal dystrophy

A case of Fuchs' corneal dystrophy is presented. The patient, a 70-year-old white woman, had bilateral decreasing vision, especially while reading and driving at night. Clinical features were characteristic of Fuchs' corneal dystrophy. Ultrastructural studies demonstrated findings in Descemet's membrane typical of those previously reported with numerous tactoids of fibrous long-spacing collagen in the posterior collagenous layer and in the guttata. In the endothelial cells were encapsulated ellipsoid viral particles, 400 nm long and 225 nm in diameter. They contained an outer and inner membrane with an electron-dense intervening region and a central dense core. Nucleocapsids were present in the endothelial cells and stromal keratocytes. The authors suggest that the pathogenesis of Fuchs' corneal dystrophy may be endothelial damage, and that in this case, the etiology is a viral infection.

Fuchs' corneal dystrophy. A clinicopathologic study of the variation in corneal edema

Corneal buttons from six patients with Fuchs' dystrophy had varying degrees of clinical edema measured in most cases by preoperative optical or ultrasonic pachymetry. These were sectioned in the operating room so that histologic correlations could be made. Histologically, marked thickening of Descemet's membrane and abnormal corneal endothelium corresponded to areas of severe clinical edema and were usually located in the central and paracentral regions. Descemet's membrane displayed multiple prominent guttata of varying size and shape, either facing the anterior chamber, or buried within multilaminar Descemet's membrane. In some corneas, aggregates of 10 nm fibrils were seen at the edges of guttata, corresponding to areas that stained for oxytalan fibrils. The endothelium was attenuated underlying the guttata. Clinical edema was not present unless accompanied by marked thickening of Descemet's membrane with multiple guttata and attenuation of corneal endothelium. The peripheral cornea was relatively clear clinically and showed minimal histologic changes.

Pump function of the human corneal endothelium. Effects of age and cornea guttata

The specific binding of tritiated ouabain to endothelial Na/K ATPase was used to quantitate the density of pump sites in the human corneal endothelium. Donor eyes, unsuitable for use in keratoplasty, were obtained from the Wisconsin Lions Eye Bank. The endothelium of each donor eye was examined using wide-field specular microscopy, and the specular micrographs were traced and digitized for the determination of cell density. Ouabain binding was measured in matched pairs of isolated endothelial sheets. A total of 26 pairs of donor eyes, ranging in age from 11 through 91 years, were studied. Twenty pairs, determined to have normal endothelia, were found to have a constant pump site density which was independent of donor age. Six donor pairs had moderate guttata; in this group pump site density was significantly increased. These results indicate that, although pump site density is normally constant in the human corneal endothelium, conditions which increase endothelial permeability, such as guttata, can cause a compensatory increase in pump site density and presumably pump function.

Color specular microscopy of disorders involving the corneal epithelium

Color specular microscopy, a noninvasive, in vivo microscopic technique, was utilized to study the corneal epithelium in 17 patients including eight with keratoconus, seven with bullous keratopathy, and two with Fuchs' corneal dystrophy. Color specular microscopy was also performed on rabbit corneas with experimental surgical trauma. Changes observed by specular microscopy in these diseased states correlated with alterations noted by light microscopy and scanning and transmission electron microscopy. Specular microscopy can provide detailed in vivo cellular morphology of the ocular surface, obviating the need for tissue biopsy. Thus, specular microscopy is a valuable diagnostic technique available for the clinician to monitor changes of the diseased ocular surface.

Is there an association between Fuchs' endothelial dystrophy and cardiovascular disease?

In order to investigate whether there is a clinical association between Fuchs' endothelial dystrophy of the cornea and atherosclerosis, the prevalence of cardiovascular disease was studied retrospectively in 27 patients with Fuchs' dystrophy and in 27 age- and sex-matched controls. The presence of cardiovascular disease was judged from a patient history of myocardial infarction, angina pectoris or heart insufficiency treated by medicaments and was found in 44% of the group with Fuchs' dystrophy and in 11% of the control group (P less than 0.05). The hypothesis is advanced that there may exist a common endothelial factor of possible significance for the development of corneal endothelial dystrophy, as well as the development of atherosclerotic lesions.

The ultrastructure of Descemet's membrane. III. Fuchs' dystrophy

The ultrastructure of Descemet's membrane was studied by transmission electron microscopy in corneal buttons removed from 11 phakic eyes with Fuchs' dystrophy. Abnormalities in Descemet's membrane consistent with abnormal endothelial function early in life (prior to age 20 years) were present in all corneas. Thus, despite the relatively late clinical onset of Fuch's dystrophy, endothelial abnormalities are present quite early in life in this disease. An abnormal fibrillar layer was thicker in those corneas with greater stromal and epithelial edema, possibly indicating that this layer is formed mainly during periods of endothelial decompensation.

A specular microscopic study of families with endothelial dystrophy

A prospective study of 12 families in which the proband had Fuchs's dystrophy was undertaken. Forty-four relatives were examined with the clinical specular microscope. Nine relatives, all women over 40 years of age, were affected. The mean endothelial cell density for unaffected relatives was 2889 cells/mm2 in the right eye and 2923 cells/mm2 in the left eye. Variability in endothelial cell size was not present in unaffected relatives but was present in those relatives with cornea guttata. Endothelial cell density decreased with age. The mean corneal thickness for unaffected and affected relatives was 0.51 mm and 0.53 mm, respectively. Unaffected relatives were compared with a control group with respect to endothelial cell density and corneal thickness. No significant difference was found between the 2 groups. In this study the clinical specular microscope failed to differentiate between controls and relatives of patients with Fuchs's dystrophy who at the time of examination did not have endothelial dystrophy. The instrument, therefore, could not be used to identify endothelial characteristics not visible with the slit-lamp which might be the forerunner of endothelial dystrophy.

Endothelial function in patients with cornea guttata

Measurements of corneal thickness, endothelial cell size, endothelial permeability to fluorescein, and intraocular pressure were made in two groups of human subjects: 21 persons with cornea guttata (early Fuchs dystrophy without epithelial edema) and 17 persons age- and sex-matched but with normal corneas. Statistically significant differences were found between the two groups in all four measured variables. The two groups did not differ with respect to the variability in endothelial cell sizes. There were statistically significant positive correlations between endothelial permeability to fluorescein, endothelial cell size, and corneal thickness. The endothelial pump rate was calculated for each group, and the difference was not statistically significant. Our results suggest that the earliest defect in Fuchs' dystrophy is solely a breakdown in barrier function and thus increased permeability, resulting in a thicker cornea.

Endothelial mosaic in Fuchs' dystrophy. A qualitative evaluation with the specular microscope

The progressive morphological changes of cornea guttata in Fuchs' endothelial dystrophy have been characterized by clinical specular photomicroscopy. Five specific stages in the development of excrescences can be discerned using this in vivo technique. Several stages can be observed in the same cornea at a given time, although in most cases the majority of guttate changes seemed to have progressed to the same stage of development. All five stages of cornea guttata discerned in this study can occur in a cornea clinically free of edema. Two types of cornea guttata can be identified in vivo. One has a smooth, regular posterior surface, whereas the posterior contour of the second is irregular.

Keratoplasty in aphakic eyes with corneal edema: results in 100 cases with 10-year follow-up

Penetrating keratoplasties were performed in 100 patients with bullous keratopathy and aphakia. In 85% of cases, edema was due to Fuchs' dystrophy. Cases were divided into eyes with good, fair, and poor prognosis, depending on the presence of glaucoma, anterior segment pathology and corneal vascularization. The three combined groups had 78% clear grafts during the first year, but when results were correlated with the prognostic groups, there were 85% of clear grafts in Group I, 78% in Group II, and 60% in Group III. The number of clear grafts dropped prominently in Groups II and III after the second year. At the end of ten years, 7 of 15 clear grafts corresponded to Group I. The most common possible causes of graft failure not related to donor tissue were: Vitreous in contact with the graft, glaucoma, and anterior segment pathology.

Inheritance of Fuchs' combined dystrophy

The inheritance pattern of Fuchs' combined corneal dystrophy is not confirmed. Published pedigrees fail to demonstrate a 50% segregation and sex ratio. They include no more than two generations of affected individuals and indicate a strong, female predilection. The pedigree we will present shows 16 affected persons in four generations. The ratio of affected to unaffected and men to women is 1:1. Penetrance is apparently 100%. Nine of the affected are under 50 years of age; four are subteen age. Light and electron micrographs of corneal tissue from three patients in three different generations are consistent with the diagnosis of Fuchs' dystrophy. Fuchs' dystrophy can therefore be established as a classic autosomal dominant pattern.

Keratoplasty in aphakic eyes with corneal edema. Results in 100 cases with 10-year followup

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Corneal dystrophies. II. Endothelial dystrophies

In general, endothelial dystrophies present three types of clinical manifestations: 1) production of collagenous tissue posterior to Descemet's membrane which appears as cornea guttata, polymorphic excrescences or gray sheets; 2) a disrupted endothelial mosaic in specular reflection; and 3) corneal edema as a reflection of decreased endothelial barrier and pump functions. In this review, the authors discuss three endothelial dystrophies -- Fuchs', posterior polymorphous and congenital hereditary. They describe the clinical, histopathologic and biochemical features, and illustrate each dystrophy with a composite drawing. Dystrophies of the epithelium, Bowman's layer, and stroma were reviewed separately in the September-October 1978 issue of this journal.

Optometric management of Fuchs's endothelial dystrophy

Fuchs's endothelial dystrophy interferes with removal of fluid from the cornea by the endothelium. It progresses through stages of corneal guttata, corneal edema, bullous keratopathy, vascularization, and scarring, and complications such as glaucoma or infection. The optometrist can detect this disorder and manage its early stages as well as provide counseling and proper referral. This paper includes a case study and a discussion of the course and treatment of this disease.

Corneal dystrophies. I. Dystrophies of the epithelium, Bowman's layer and stroma

Most corneal dystrophies are autosomal dominant, bilateral disorders that primarily affect one layer of an otherwise normal cornea, progress slowly after their appearance in the first or second decade, and are not associated with a systemic disease. Epithelial basement membrane dystrophy and Fuchs' endothelial dystrophy are seen commonly by the general ophthalmologist; fleck, posterior polymorphous, granular or lattice dystrophies are seen more rarely, and others may never be seen in general office practice. While the distinctive clinical appearance of most corneal dystrophies allows accurate diagnosis, the integration of slitlamp findings with histopathologic and biochemical findings aids in the understanding of the clinical observations and provides a more rational basis for therapy. Transmission electtron microscopy is the most accurate method of histopathologic diagnosis. Epithelial dystrophies usually manifest intraepithelial cysts and abnormal basement membrane. In stromal dystrophies, an abnormal substance accumulates within the keratocytes or among the collagen fibrils; it may be an excess normal metabolite (like glycosaminoglycans in macular dystrophy), a material not usually present (like amyloid in lattice dystrophy), or a substance of unknown composition (like hyaline in granular dystrophy). Each dystrophy is illustrated with a composite drawing. Endothelial dystrophies will be reviewed separately in a second article.