Dataset Information

The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia.

ABSTRACT:

Purpose

We aimed to study the effect of stimulus contrast on the orientation selectivity of interocular interaction in amblyopia using a dichoptic masking paradigm.

Methods

Eight adults with anisometropic or mixed amblyopia and 10 control adults participated in our study. The contrast threshold in discriminating a target Gabor in the tested eye was measured with mean luminance in the untested eye, as well as with a bandpass oriented filtered noise in the other eye at low spatial frequency (0.25 c/d). Threshold elevation, which represents interocular suppression, was assessed using a the dichoptic masking paradigm (i.e. the contrast threshold difference between the target only and masked conditions), for each eye. Orientation selectivity of the interocular suppression as reflected by dichoptic masking was quantified by the difference between the parallel and orthogonal masking configurations. Two levels of mask's contrast (3 times or 10 times that of an individual's contrast threshold) were tested in this study.

Results

The strength of dichoptic masking suppression was stronger at high, rather than low mask contrast in both amblyopic and control subjects. Normal controls showed orientation-dependent dichoptic masking suppression both under high and low contrast levels. However, amblyopes showed orientation-tuned dichoptic masking suppression only under the high contrast level, but untuned under the low contrast level.

Conclusions

We demonstrate that interocular suppression assessed by dichoptic masking is contrast-dependent in amblyopia, being orientation-tuned only at high suprathreshold contrast levels of the mask.

SUBMITTER: Gong L

PROVIDER: S-EPMC9187942 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature

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Publications

The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia.

Gong Ling L Wei Lili L Yu Xi X Reynaud Alexandre A Hess Robert F RF Zhou Jiawei J

Investigative ophthalmology & visual science 20220601 6

<h4>Purpose</h4>We aimed to study the effect of stimulus contrast on the orientation selectivity of interocular interaction in amblyopia using a dichoptic masking paradigm.<h4>Methods</h4>Eight adults with anisometropic or mixed amblyopia and 10 control adults participated in our study. The contrast threshold in discriminating a target Gabor in the tested eye was measured with mean luminance in the untested eye, as well as with a bandpass oriented filtered noise in the other eye at low spatial f ...[more]

PMID: 35675061

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Project description:PurposeDichoptic training is becoming a popular tool in amblyopia treatment. Here we investigated the effects of dichoptic demasking training in children with amblyopia who never received patching treatment (NPT group) or were no longer responsive to patching (PT group).MethodsFourteen NPT and thirteen PT amblyopes (6-16.5 years; 24 anisometropic, two strabismus, and one mixed) received dichoptic demasking training for 17 to 22 sessions. They used the amblyopic eye (AE) to practice contrast discrimination between a pair of Gabors that were dichoptically masked by a band-filtered noise pattern simultaneously presented in the fellow eye (FE). Dichoptic learning was quantified by the increase of maximal tolerable noise contrast (TNC) for AE contrast discrimination. Computerized visual acuities and contrast sensitivity functions for both eyes and the Randot stereoacuity were measured before and after training.ResultsTraining improved maximal TNC by six to eight times in both groups, along with a boost of AE acuities by 0.15 logMAR (P < 0.001) in the NPT group and 0.06 logMAR (P < 0.001) in the PT group. This visual acuity improvement was significantly dependent on the pretraining acuity. Stereoacuity was significantly improved by 41.6% (P = 0.002) in the NPT group and 64.2% (P < 0.001) in the PT group. The stereoacuity gain was correlated to the pretraining interocular acuity difference (r = -0.49, P = 0.010), but not to the interocular acuity difference change (r = -0.28, P = 0.15). Training improved AE contrast sensitivity in the NPT group (P = 0.009) but not the PT group (P = 0.76). Moreover, the learning effects in 12 retested observers were retained for 10 to 24 months.ConclusionsDichoptic training can improve, and sometimes even restore, the stereoacuity of amblyopic children, especially those with mild amblyopia (amblyopic VA ≦0.28 logMAR). The dissociation of stereoacuity gain and the interocular acuity difference change suggests that the stereoacuity gain may not result from a reduced interocular suppression in most amblyopes. Rather, the amblyopes may have learned to attend to, or readout, the stimulus information to improve stereopsis.

Dataset Information

The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia.

Purpose

Methods

Results

Conclusions

Publications

The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia.

Similar Datasets

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