Blur Adaptation to Central Retinal Disease

Abstract

PurposeThe long-term, low-resolution vision experienced by individuals affected by retinal disease that causes central vision loss (CVL) may change their perception of blur through adaptation. This study used a short-term adaptation paradigm to evaluate adaptation to blur and sharpness in patients with CVL.MethodsA variation of Webster's procedure was used to measure the point of subjective neutrality (PSN). The image that appeared normal after adaptation to each of seven blur and sharpness levels (PSN) was measured in 12 patients with CVL (20/60 to 20/320) and 5 subjects with normal sight (NS). Patients with CVL used a preferred retinal locus to view the images. Small control studies investigated the effects of long-term and medium-term (1 hour) defocus and diffusive blur.ResultsAdaptation was reliably measured in patients with CVL and in the peripheral vision of NS subjects. The shape of adaptation curves was similar in patients with CVL and both central and peripheral vision of NS subjects. No statistical correlations were found between adaptation and age, visual acuity, retinal eccentricity, or contrast sensitivity. Long-term blur experience by a non-CVL myopic participant caused a shift in the adaptation function. Conversely, medium-term adaptation did not cause a shift in the adaptation function.ConclusionsBlur and sharp short-term adaptation occurred in peripheral vision of normal and diseased retinas. In most patients with CVL, neither adaptation nor blur perception was affected by long-term attention to peripheral low-resolution vision. The impact of blur/sharp adaptation on the benefit of image enhancement techniques for patients with CVL is discussed.

Blur adaptation: clinical and refractive considerations

“…As the capability to detect high spatial frequencies declines with increasing eccentricity, yet the adaptation effects were unaffected, this may indicate that recalibration of the sensitivity to high spatial frequencies may only play a limited role in blur adaptation. Vera‐Diaz et al also found that eccentricity had little impact on the ability of blur adaptation to shift the point of subjective neutrality – the adaptive effects were similar when normally sighted observers saw a target straight‐on, or when looking up to 10° past its edge.…”

“…Vera-Diaz et al 46 assessed blur adaptation (using the method described by Webster et al 14 and Vera-Diaz et al 36 ) in a small number of patients with central vision loss compared with normally sighted controls. Blur adaptation was evident in the peripheral field of normal observers and those with central vision loss.…”

Baseline metrics that may predict future myopia in young children

“…Ocular health was evaluated with a slit lamp and binocular indirect Note that although the experimental conducted at the same time as the clinical tests reported in this manuscript, these are part of the wider study, and they will be reported separately. Preliminary data have been presented at ARVO [66][67][68][69][70][71] and American Academy of Optometry meetings. 72 ophthalmoscopy and intraocular pressure (IOP) with an iCare tonometer (icare -world.com).…”