Stručni rad

Contrast Sensitivity in Strabologic Functional Tests

Ljubica Dorn
Jelena Petrinović-Dorešić

Sažetak

In physical meaning, contrast denotes the relationship between the luminance of an object and its immediate background. Retinal receptive fields and systems of P cell and M cell neurons are involved in contrast perception. P cells are thought to subserve light contrast and high spatial frequency resolution. M cells may be involved with information on high temporal and low spatial frequency. In amblyopia, considering developmental defect of spatial visual processing in the central nervous system, the main features are decreased recognition, Vernier and grating acuity, decreased contrast sensitivity and spatial localization. The aim of this report is to show how contrast sensitivity testing can contribute to functional examinations in strabismus and amblyopia. In our patients with different types of amblyopia and refractive errors we performed contrast sensitivity testing and comparison with visual acuity assessed by standard Snellen charts. On contrast sensitivity measuring we used Ginsburg method (Vistech VCTS and Vector Vision CSV-1000 charts). The results on each patient were recorded in an evaluation chart which gives the contrast sensitivity curve. The deficit in contrast sensitivity in anisometropic amblyopia was most pronounced at high spatial frequencies. Strabismic amblyopia also showed the loss at high spatial frequencies but Snellen visual acuity was worse than grating acuity. Contrast sensitivity in strabismic amblyopia may be normal or abnormal at high frequencies. In visual deprivation amblyopia, both spatial localization and contrast sensitivity are affected. In comparison with standard Snellen visual acuity, contrast sensitivity testing is a more sensitive measure of visual function. Contrast sensitivity is also a sensitive tool to detect suppression even in patients with normal or near normal visual acuity. Preschool children can easily cooperate in this type of visual testing.

Ključne riječi

Contrast sensitivity; Strabismology; Functional examinations

Hrčak ID:

22759

URI

https://hrcak.srce.hr/22759

Datum izdavanja:

1.4.2008.

Podaci na drugim jezicima: hrvatski

Posjeta: 3.849 *