Orientation-specific long-term neural adaptation of the visual system in keratoconus
Autor: | Chuan Hu, Alexander Schill, Gareth D Hastings, Raymond A. Applegate, Daniel R. Coates, Jason D Marsack |
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Rok vydání: | 2021 |
Předmět: |
Optics and Photonics
Keratoconus medicine.medical_specialty Visual acuity genetic structures media_common.quotation_subject Visual Acuity Rotational symmetry Ellipse Article 050105 experimental psychology Contrast Sensitivity 03 medical and health sciences 0302 clinical medicine Ophthalmology medicine Humans Contrast (vision) 0501 psychology and cognitive sciences Vision Ocular media_common Mathematics 05 social sciences Neural adaptation Corneal Topography medicine.disease eye diseases Sensory Systems medicine.anatomical_structure Oblique effect sense organs Spatial frequency medicine.symptom 030217 neurology & neurosurgery |
Zdroj: | Vision Res |
ISSN: | 0042-6989 |
Popis: | Eyes with the corneal ectasia keratoconus have performed better than expected (e.g. visual acuity) given their elevated levels of higher-order aberrations that cause rotationally asymmetric retinal blur. Adapted neural processing has been suggested as an explanation but has not been measured across multiple meridional orientations. Using a custom Maxwellian-view laser interferometer to bypass ocular optics, sinusoidal grating neural contrast sensitivity was measured in six eyes (three subjects) with keratoconus and four typical eyes (two subjects) at six spatial frequencies and eight orientations using a two-interval forced-choice paradigm. Total measurement duration was 24 to 28 hours per subject. Neural contrast sensitivity functions of typical eyes agreed with literature and generally showed the oblique effect on a linear-scale and rotational symmetry on a log-scale (rotational symmetry was quantified as the ratio of the minor and major radii of an ellipse fit to all orientations within each spatial frequency; typical eye mean 0.93, median 0.93; where a circle = 1). Mean sensitivities of eyes with keratoconus were 20% to 60% lower (at lower and higher spatial frequencies respectively) than typical eyes. Orientation-specific neural contrast sensitivity functions in keratoconus showed substantial rotational asymmetry (ellipse radii ratio: mean 0.84; median 0.86) and large meridional reductions. The visual image quality metric VSX was used with a permutation test to combine the asymmetric optical aberrations of the eyes with keratoconus and their measured asymmetric neural functions, which illustrated how the neural sensitivities generally mitigated the detrimental effects of the optics. |
Databáze: | OpenAIRE |
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