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Fatema Firoz Ghasia, Jordan Murray, Aasef Shaikh; Attention Deficits in Amblyopia Patients. Invest. Ophthalmol. Vis. Sci. 2020;61(7):860.
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Amblyopic patients have increased fixation instability particularly of the amblyopic eye. Amblyopes also exhibit inter-ocular suppression of the amblyopic eye when both eyes are viewing. Abnormal allocation of visual attention between the two eyes may play a role in suppression. Increased fixation instability could interfere with the ability to allocate attention. The purpose of the study was to investigate the effects of fixation eye movement abnormalities on attention allocation in amblyopia.
We measured attention allocation (response time) in 6 amblyopic and 5 controls while they focused on stimuli presented to one eye (focused attention-fellow OR amblyopic eye) or to both eyes (divided attention- fellow AND amblyopic eye) under binocular and dichoptic viewing conditions. Subjects were presented with side-by-side pairs of large letters composed of smaller letters. Subjects were asked to determine whether a given letter is present at the global level (large letters), local level (smaller letters), or either level (large and small letters). We categorized amblyopic patients into those lacking nystagmus, those with Fusion maldevelopment nystagmus (FMN) and those with nystagmus but without the typical features of FMN.
FMN patients had increased reaction times (sec) during local (controls:0.62;No nystagmus:0.62;Nystagmus no FMN:0.74 and FMN:0.75, p=0.009)and global (controls:0.63;No nystagmus:0.63;Nystagmus no FMN:0.79 and FMN:0.70, p=0.06) stimuli under divided attention task during binocular viewing conditions. An increase in reaction time was seen during focused attention fellow eye task for local (controls:0.48;No nystagmus:0.57; Nystagmus no FMN:0.57 and FMN:0.86, p=0.001)and global stimuli (controls:0.59;No nystagmus:0.54;Nystagmus no FMN:0.55 and FMN:0.65, p=0.03)as well as during focused attention amblyopic eye task for local (controls:0.48;No nystagmus:0.50;Nystagmus no FMN:0.65 and FMN:0.66, p=0.001)and global stimuli (controls:0.50;No nystagmus:0.58;Nystagmus no FMN:0.55 and FMN:0.59, p=0.03)detection during binocular viewing. The reaction times obtained for similar tasks under dichoptic viewing condition were worse compared to binocular viewing conditions for FMN patients.
FMN patients have greater impairment of attention allocation. This could have implications for treatment effectiveness of dichoptic therapies where attention allocation of the amblyopic eye to the presented stimuli is necessary.
This is a 2020 ARVO Annual Meeting abstract.
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