AbstractBackgroundAlzheimer’s disease (AD) is characterized by early impairment of memory. However, recent studies have revealed early abnormalities in other cognitive functions, such as visuospatial functions, the ability to process visual information, and visuospatial attention. The Judgment of Line Orientation (JLO) is a neuropsychological test commonly used to measure visuoperceptual and visuospatial abilities. Eye movements are a practical method for assessing cognitive processes during visual tasks. This study aimed to investigate eye movement patterns during the JLO test in AD and amnestic mild cognitive impairment (aMCI).MethodThe study sample consisted of 16 patients with AD (mean age 72.2±7.9 years), 34 patients with aMCI (mean age 70.3±6.5 years), and 37 HC (mean age 67.7±6.7 years). Eye movements during the 30‐item Benton JLO test were recorded with the EyeLink 1000 Plus. Fixation duration (FD), the response time (RT), and the total number of correct and incorrect responses were calculated.ResultThe mean of JLO scores was significantly lower in aMCI and AD than in HCs (p<0.001). In the correct responses, Patients with AD had a statistically significantly less FD on the test lines compared HCs (p = 0.019). Moreover, FD on the reference lines of correct responses was significantly decreased in AD (p = 0.006) and aMCI (p = 0.016) compared to HCs. In the incorrect responses, FD on the test lines was significantly increased in aMCI (p = 0.009) and AD (p = 0.008) compared to the HCs. The FD on the reference lines of the incorrect responses was increased in AD (p = 0.021) and aMCI (p = 0.013) groups compared to HCs. Additionally, AD (p = 0.001) and aMCI (p = 0.004) groups showed significantly increased RT in incorrect responses compared to HCs.ConclusionThis study showed that the AD and aMCI groups looked at visual stimuli with less fixation duration than HCs. The patient groups looked at the target for a longer time in incorrectly answered trials and had a delay in making decisions. The findings may indicate difficulties in visual‐spatial processing and visual‐attention deficit in these patient groups and provide insight into the underlying cognitive processes involved in visual perception in AD and MCI.