Metabolic compatibility of abattoir and human corneas: an ex vivo 31P nuclear magnetic resonance spectroscopic study of intact tissues.

This study establishes the metabolic similarities and differences of intact abattoir corneas and the human cornea ex vivo, using 31P nuclear magnetic resonance spectroscopy. Phosphorylated sugars (SP), inorganic orthophosphate (Pi), phosphodiesters, ATP, ADP, and the nucleoside diphosphosugars and dinucleotides (NS&DN) were quantitated. The intracorneal pH also was determined. In addition, metabolic indices ATP/Pi, ATP/ADP, ATP/(ADP + Pi), SP/Pi, the phosphorylation potential, and the 31P energy modulus were calculated. Significant differences were observed between the abattoir and human corneas in phosphorylated sugars, NS&DN, and intracorneal pH, as well as in the indices ATP/ADP and SP/Pi. The overall energy status as measured by the 31P energy modulus was significantly higher in the bovine cornea when compared to the porcine and human corneas, suggestive of a very high energy reserve in the bovine cornea.

Corneal steepening with final suture removal after penetrating keratoplasty.

We reviewed 53 patients after they underwent penetrating keratoplasty, comparing the change in average corneal curvature before and after final suture removal 15-18 months postsurgery. In 29 eyes with keratoconus, there was a significant increase in average curvature of 3.48 diopters +/- 3.76 (p less than 0.0005). In 24 eyes with other diagnoses, there was also a significant increase in the average curvature of 3.26 diopters +/- 3.98, (p less than 0.0005). The difference between these groups was not significant. The amount of steepening correlated negatively (-.6494) with the average corneal curvature before suture removal (p less than 0.005). We found no change in the average astigmatism after suture removal; however, large changes in astigmatism occurred unpredictably with some patients. This study shows that corneal curvature after penetrating keratoplasty steepens after suture removal, particularly in flat corneas, and astigmatism may shift unpredictably.

[Tear film diagnosis in contact lens wearers]. / Tränenfilmdiagnostik bei Kontaktlinsenträgern.

Contact lenses have an intimate relationship with the precorneal tear film and it is important to attempt to prognosticate the likelihood of successful contact lens wear by evaluating, both quantitative and qualitative aspects of the precorneal tear film. Aspects of history diagnostic methods and general aspects which are necessary to notice prior to contact lens fitting are described in this review.

Surface cell morphology of the anesthetic human cornea: a color specular microscopic study.

The technique of color specular microscopy has been utilized to study the surface cell morphology of the human cornea in 6 subjects with profound corneal anesthesia from diverse causes. In an analysis of cell area, perimeter, and shape, anesthetic corneas showed a statistically significant increase in cell size and perimeter. In addition, there was a loss of cellular outlines and overall increase in rose bengal staining of cells. We believe that these cellular microscopic changes reflect profound changes in epithelial cell turnover related to a decrease in neurohumoral transmitters known to be necessary for maintenance of normal corneal morphology and function.

The effects of extended-wear hydrophilic contact lenses on the human corneal epithelium.

We used wide-field color specular microscopy of the human corneal surface to study the morphologic changes that occur under extended-wear contact lenses. There was a shift in the frequency distribution of surface cells by size to larger cells, suggesting a prolonged residence time on the ocular surface. Other abnormalities included retained desiccated mucin, coarse mucus plaques, and palisading of cells.

An in vivo study of the corneal surface in keratoconjunctivitis sicca.

Thirteen normal subjects and thirteen subjects with bona fide keratoconjunctivitis sicca were examined employing wide-field colour specular microscopy of the corneal epithelium. The prevalence of small, medium and large cells is different in these two groups with a shift to small cells in patients with keratoconjunctivitis. Increased rose bengal dye uptake filaments, coarse mucus plaques and pre-exfoliative sheets are also seen in keratoconjunctivitis sicca. These findings suggest an accelerated epithelial cell loss from the surface of the eye in keratoconjunctivitis sicca.

An in vivo study of corneal surface morphologic features in patients with keratoconjunctivitis sicca.

We used wide-field color specular microscopy to study the corneal epithelium of 13 normal subjects and 13 patients with keratoconjunctivitis sicca. The frequencies of small, medium, and large cells were different in the two groups, with a shift to small cells in patients with keratoconjunctivitis sicca. Increased uptake of rose bengal dye, filaments, coarse mucus plaques, and pre-exfoliative sheets were also found in the patients with keratoconjunctivitis sicca. These findings suggest accelerated epithelial cell loss from the surface of the eye in keratoconjunctivitis sicca.

Enhancing the creative problem-solving skills of educable mentally retarded students.

60 educable mentally retarded students from 3 schools in a large urban school system received 9 wk. of instruction from an adaptation of the Productive Thinking Program. Their performance on measures of creative thinking was compared with that of 60 students who received no additional instruction. The conclusions drawn were that (1) special attention to creative thinking training for educable mentally retarded students may be quite effective and results stable over time and (2) the measures of fluency, flexibility, and originality are the most useful in assessing creative thinking for this group.