Relative contents of sodium, potassium, water and dry matter in human senile cataractous lenses in relation to anterior capsular/subcapsular opacity

Lens thickness in atopic cataract: case-control study

PURPOSE

To examine whether atopic cataracts are associated with thinner lenses.

SETTING

Department of Ophthalmology, Jikei University Hospital, Tokyo, Japan.

DESIGN

Retrospective matched case-control study.

METHODS

31 eyes with atopic cataracts, 62 with nonatopic cataracts, and 31 without cataracts were analyzed. Each group was matched for age (±4 years) and sex.

RESULTS

The mean lens thickness (LT) was 3.76 ± 0.40 mm, 3.94 ± 0.49 mm, and 4.11 ± 0.40 mm in eyes with atopic cataracts, nonatopic cataracts, and normal lenses, respectively. Repeated-measures analysis of variance showed that the LT in the atopic cataract group was significantly thinner than that in the nonatopic cataract ( P = .036) and normal lens ( P < .001) groups. In multivariate logistic regression analysis, a thinner LT was negatively correlated with age (odds ratio [OR], 0.91; 95% CI, 0.86-0.96) and positively correlated with anterior subcapsular cataract (ASC) (OR, 5.61; 95% CI, 1.97-15.99). Atopy was not a significant factor. 24 (38.7%) of the 62 eyes with nonatopic cataracts and 24 (77.4%) of the 31 eyes with atopic cataracts had ASC.

CONCLUSIONS

The lenses of eyes with atopic cataracts were thinner than those of controls. Atopic cataracts frequently present with anterior subcapsular opacity, which is associated with lens thinning.

Relative contents of sodium, potassium, and dry matter in diabetic cataractous lenses

Cataractous lenses from diabetic patients were pre-operatively divided into 3 groups according to the biomicroscopical appearance of the lenses and biochemical analyses of CNa+, CK+, and dry matter were performed. 1) Immature cataractous lenses without anterior capsular/subcapsular opacity (ac-sco): (N=4) CNa+ = 35 meq/kg lens water, CK+ = 164 meq/kg lens water, dry matter 24%. 2) Immature cataractous lenses with ac-sco: (N=12) CNa+ = 151 meq/kg lens water, CK+ = 62 meq/kg lens water, dry matter 33%. 3) Totally opaque lens: (N=1) CNa+ = 185 meq/kg lens water, CK+ = 12 meq/kg lens water, dry matter 19%. The concentrations of sodium, potassium, and dry matter were equal to the findings in senile non diabetic cataractous lenses.

Human senile cataract. Light- and electron-microscopic studies of the morphology of the anterior lens structures, with special reference of anterior capsular/subcapsular opacity

Light- and electron-microscopic studies of human senile cataractous lenses with and without biomicroscopically detectable anterior capsular/subcapsular opacity (ACSCO) revealed the main difference between the two types of cataract to be in the subepithelial cortex, where ACSCO lenses showed disintegrating cortex fibres, fibres of the deep cortical type and even in some cases collapsed fibres. These findings were considered to be associated with the decomposition and disappearance of the superficial cortex in ACSCO lenses. Numerous mitochondria in the epithelium of ACSCO lenses point towards a high oxidative metabolism, which may facilitate active transport across the epithelium. No difference in capsular surface morphology between cataractous lenses with and without ACSCO was found by scanning electron microscopy. Transmission electron microscopy showed in both categories of lenses granular inclusions in the capsules, most pronounced in totally opaque lenses. Large intercellular vacuoles were seen in the anterior part of the epithelium, both light- and electron-microscopically in both categories. Consequently, these ultrastructural changes do not seem to form part of the biomicroscopical picture of ACSCO. Based on our study, we prefer the term: ASCO (anterior subcapsular opacity) in place of ACSCO, the latter term having been used by us previously.

Human senile cataract and Na-K ATP'ase activity in the anterior lens structures with special reference to anterior capsular/subcapsular opacity

Location and in vitro determination of Na-K ATP'ase activity in the anterior structures of individual human lenses with senile cataract are reported, with special reference to anterior capsular/subcapsular opacity (ACSCO). Histochemically, ATP'ase reaction products were found exclusively in the epithelium. Even totally opaque lenses showed strong positive reactions. Biochemically, increasing ratios of Na+/K+ concentrations in the assay medium resulted in an increase in enzyme activity to a limited degree, whereafter the activity remained stable. We cannot decide whether the Na-K ATP'ase activity of the anterior lens structures is unchanged in relation to ACSCO as indicated by our figures. For there are methodological problems, although our analytical error, expressed as the variation coefficient for slaughterhouse pig lenses, seems to be one of the lowest so far reported in the literature on interindividual, non-pooled material.

Variations of lens thickness in relation to biomicroscopic types of human senile cataract

The results are reported of 38 ultrasonographic in vivo mensurations of intraindividual differences in axial thickness between a cataractous lens in one eye and a biomicroscopically clear or slightly cataractous lens (incipient deep cortical opacity) in the other. Obviously intumescent cataractous lenses were excluded. In general, the cataractous lens was thinner than the contralateral clear or slightly cataractous lens. Large decreases in lens thickness appeared in lenses with the capsule-near opacities of posterior subcapsular cataract (PSC) + anterior capsular/subcapsular opacity (ACSCO). PSC was more closely correlated to lens thinning than was ACSCO. Nuclear cataract very often occurred in thin lenses, but did not appear to cause lens thinning per se. Deep cortical opacity was not associated with lens thinning. The present results contributed to our argumentation that the decrease in lens thickness is due to a leak of lens material through the "lens membrane" beside a possible cessation of growth of the lens fibres.