Biomedical subjects

K C Koslowe

Publications and source records attributed to K C Koslowe.

5 recordsLinked to original sources

PubMed1991

Evaluation of accommotrac biofeedback training for myopia control.

A new treatment for myopia, biofeedback training for control of accommodation, has been proposed and developed over the past decade. Various reports in the literature show marked inconsistencies in the results of such treatment. A double-masked study with experimental and control groups of 15 subjects each was designed to obtain a definitive answer concerning the efficacy of this method. The parameters evaluated were visual acuity, cycloplegic and noncycloplegic retinoscopy, subjective refraction, amplitude of accommodation, and flexibility of accommodation. In all categories no significant difference was found between the control and experimental subjects. The consequences of these findings are discussed as to the benefit of treatments using this method and avenues to explore in future studies.

Accommodation, Ocular↗

PubMed1986

Hypermetropia in dark reared chicks and the effect of lid suture.

Two experimental groups of domestic fowl chicks were reared in darkness. One group was normal (DR) and the second had unilateral lid closure (DRC). A control group was reared in normal illumination (LR). The optical components of the eye were examined by retinoscopy, keratometry and phacometry while physical measurements were made using ultrasonography and micrometry. The DR chicks developed a significant hyperopia (+3.11 D) compared to the LR chicks (+0.65 D), attributed to a significant decrease in corneal height and lens thickness. A significant increase in the anteroposterior axis of the DR chicks tends to reduce the dark induced hyperopia. Lid closure in the DRC chicks increases the hyperopic effect by +3.07 D due to additional corneal flattening. These results reinforce our proposal of the chick eye as a model for research in the various forms of ametropia.

Animals↗

PubMed1984

Eyelid closure effects on the refractive error of the eye in dark- and in light-reared kittens.

Kittens reared in the dark with their eyelids sutured postnatally on one side have developed hypermetropia in the closed eye (average: +2.75 D for the horizontal meridian). This was significantly different (0.01 greater than p greater than 0.005) from the results of the open eye (+1.67 D; 180 degrees). The closed eye of light-reared kittens had similar refractive error (+0.33 D) to that of their open eye (+0.50 D), and to that of kittens light-reared with both eyes open (+0.75 D). Axial length of the closed eye in the dark-reared kittens and its corneal refractive power were smaller in comparison to the results for the open eye. It was concluded that in kittens lid closure during development in the dark induces hypermetropia.

Animals↗

PubMed1984

The optical effects of eyelid closure on the eyes of kittens reared in light and dark.

Monocular closure surgically performed during development by suturing the eyelids induced less hyperopia in the closed eye of light reared kittens (+0.95 Diopters) in comparison to the closed eyes of lid sutured dark reared kittens (+2.61 D). The normal control cats were also slightly hypermetropic (+0.69 D). While a certain proportion of myopic eyes was found in the monocularly closed light reared kittens and in the normal control cats, no one eye was myopic either in the operated or nonoperated dark reared kittens. Lid suture was found to considerably increase the hyperopia also in adult cats. The incidence of astigmatism was 47.0% for the closed eye in the lid sutured light reared kittens and 64.7% for their open eyes; for the lid sutured dark reared kittens the proportions were 45.4% and 54.5%, respectively. The incidence of astigmatism was 20.2% for the eyes of the normal control cats. Axial length of the closed eye of light (19.00 mm) and of dark (19.45 mm) reared kittens was smaller in comparison to that of the normal control cats (20.38 mm). The corneal curvature of the closed eyes of light (8.09 mm) and of the dark (8.64 mm) reared kittens was flatter than in the normal controls (7.11 mm). It is concluded that lid closure in kittens has a corneal effect, accentuating the tendency for hypermetropia naturally occurring in the dark. In the light lid closure results in an imbalanced combination of the corneal and the (axial?) visual deprivation effects, causing a considerable variability in the refractive error with a tendency for cancellation of the naturally occurring hyperopia.

Animals↗

PubMedDate not supplied

Lid suture myopia in developing chicks: optical and structural considerations.

In a group of chickens studied after lid suture in the first month post hatching an unusually high myopia was found (n = 8 eyes; average: -21.87 Diopters). The non-operated eyes of these chicks had the same optical properties (n = 4; +0.93 Diopters) as the eyes of the normal control chicks (n = 12; +0.81 Diopters). Although enlargement of the whole eye occurred, the main determinant was an axial elongation (operated eyes, 18.0 mm; nonoperated, 13.7 mm; normal controls, 14.7 mm). The axial change involves an enlargement of the posterior as well as the anterior segments of the eye. Despite several structural characteristics specific to chicks, their eyes can serve as a model for myopia research.

Animals↗