Table 2 Key data extracted from simulated hemianopia studies

Liman et al. (2012) [36]

Cohort study

n = 20

Adult subjects with no neurological or psychiatric disorders

N/A

Subjects’ eye movements were recorded under simulated HH condition during viewing and subsequent visual imagery of complex pictures

Eye movements

Saccade amplitude, number of fixations, fixation duration and global/ local ratio

Fixation duration was significantly higher in visual imagery scanpaths than in the viewing condition (session 1: 0.32 s viewing–0.39 s imagery (p < 0.001); session 3: 0.295 s viewing–0.34 s imagery).

Number of fixations was lower in visual imagery scanpaths than in the viewing condition (session 1: 12.4 viewing–9.8 imagery (p < 0.001); session 3: 12.5 viewing–9.9 imagery (p < 0.001)).

Saccade amplitudes were significantly lower in visual imagery scanpaths than in the viewing condition (session 1: 2.7° viewing–2.4° imagery (p = 0.05); session 3: 3.15° viewing–2.3° imagery (p < 0.016)).

Global/Local ratio was significantly lower in visual imagery scanpaths than in the viewing condition (session 1: 8.3 viewing - 6.3 imagery (p = 0.04); session 3: 11.25 viewing - 6.1 imagery (p < 0.001)).

Nowakowska et al (2016) [37]

Cohort study

n = 101

Adult subjects with normal or corrected-to-normal vision

N/A

Eye movements were recorded while participants searched for an emotional face among neutral faces

Eye movements

Number of fixations, saccade amplitude, proportion of saccades into the blind field

In masked conditions (blank, dot, filtered),an increased number of fixations was found (22,20,15 respectively) compared to unmodified condition (13).

No significant difference in saccadic amplitude between the saccades made into the sighted hemifield (SHF) and blind side (BHF) in the unmodified condition (p = 0.87).

In masked conditions, saccades were shorter when made towards the SHF compared with the BHF (all p values < 0.002).

The proportion of all saccades made into the BHF was significantly smaller in the blank (M = 0.44, SD = 0.11, p = 0.001), dot (M = 0.42, SD = 0.07, p < 0.001), and filtered (M = 0.47, SD = 0.06, p = 0.05) conditions compared with unmodified (M = 0.52, SD = 0.04)

Nowakowska et (2019) [38]

Case-control study

n = 34

Adult subjects with normal or corrected-to-normal vision

Participants practised three visual search tasks (repeated search task, object naming and detection task) in five testing sessions over five consecutive days

N/A

Eye movements

Reaction time, eye movement behaviour in the repeated exposure task

Simulated HH slowed search but improved over the five sessions. Most participants improved on the task later on in the week by shifting their fixations into the BHF (p = 0.002).

Schuett et al (2009a) [39]

Cohort study

n = 32

Adult subjects with normal or corrected-to-normal vision

N/A

Eye movements were recorded during manual and ocular line bisection tasks

Eye movements

Fixation range, number and duration of fixations, number and amplitude of saccades and scanpath length

During manual line bisection, the number of right-hemispace fixations in RHH (58.2 (21.9)) was higher than controls (9.89 (9.9)) and fixation duration was higher (453.7 ms, 419.2 ms respectively). Left-hemispace fixations in LHH (48.3 (23.3)) were higher than controls and fixation duration significantly increased (560.7 ms, 493.5 ms respectively).

Participants made larger saccades towards the BHF than towards the SHF (p < 0.017).

The spatial range covered by fixations was considerably larger (LHH: 12.0° (4.9), RHH: 13.3° (4.2)) than normal viewing (6.9° (5.8)), scanpaths significantly longer (LHH: 191.5° (113.1), RHH: 229.1° (89.6)) than under normal viewing conditions (50.0° (49.0)).

During ocular line bisection, the number of right-hemispace fixations in RHH (38.2 (19.6)) was higher than normal viewing (16.9 (9.8)) and fixation duration was higher (316.2 ms (92.0), 298.8 ms (109.5) respectively). Left-hemispace fixations in LHH (40.7 (19.6)) were higher than normal viewing (21.5 (15.8) and fixation duration slightly increased (366.1 ms (175.6), 353.7 ms (157.8) respectively).

Scanpaths were slightly longer (LHH: 295.2° (168.1), RHH: 290.6° (181.2)) than under normal viewing conditions (226.0° (121.4)).

Schuett et al (2009b) [40]

RCT

n = 24

Adult subjects with normal or corrected-to-normal vision

15-min session of reading and visual exploration practice

Eye movements were recorded during reading and visual exploration

Eye movements

Mean reading time, number of fixations, fixation duration, repeated fixations (%), mean number and amplitude of forward saccades, scanpath length

During visual exploration, exploration times increased, participants made many more errors and the prolonged scanpath was characterised by a higher number and duration of fixations. However, participants failed to show the expected decrease in return sweep and exploration saccadic amplitude (p = 0.126).

After visual exploration practice, participants showed a significant decrease in the number of fixations (pre: 30; post: 24), and scanpath length (pre: 125°, post: 75°). Fixation duration decreased slightly after training (380 ms) compared to pre-training (460 ms).

Schuett et al (2009c) [41]

Before-after sudy

n = 37

Adult subjects with normal or corrected-to-normal vision

Participants performed two visual exploration practice sessions (15 min each)

Eye movements were recorded during visual exploration

Eye movements

Number and mean duration of fixations, number and mean amplitude of forward saccades, mean amplitude of return sweep saccades

After visual exploration practice, number of fixations significantly reduced (LHH, pre: 24.0, post: 19.8; RHH, pre: 26.8, post: 21.1) with shorter fixation durations (LHH, pre: 463 ms, post: 407 ms; RHH, pre: 449 ms, post: 381 ms ).

There was no significant effect for overall, left- and rightward saccadic amplitude; practice did also not affect number and duration of left- and right-hemispace fixations (p = 0.141).

Zangemeister et al (2002) [42]

Before-after study

n = 16

Adult subjects with normal or corrected-to-normal vision

Eight subjects (“early training group”) were trained for 20 min with 10 deg off-field defect towards the healthy side and directly afterwards. The other 8 subjects (“late training group”) underwent 20 min of viewing without any training.

Eye movements were recorded while a series of 2 × 8 pictures were presented during simulated HH.

Eye movements

Fixation durations, saccadic amplitudes, ratio of overshoot one-step/ undershoot stair-step saccades to the BHF

For the early training group, fixation durations decreased significantly immediately after training (0.26 s) and 14 days afterwards (0.39 s) compared to pre-training (0.43 s).

Saccadic amplitude increased significantly immediately after training (6.2°) and 14 days afterwards (4.9°) compared to pre-training (3.4°).

Ratio of overshoot one-step/ undershoot stair-step saccades to the BHF significantly increased immediately after training (0.76) and 14 days afterwards (0.52) compared to pre-training (0.37).

For the late training group, fixation durations significantly decreased 14 days after training (0.29 s) compared to pre-training (0.41 s). Saccadic amplitude significantly increased 14 days post training (5.8°) compared to pre-training (3.5°). Ratio of overshoot one-step/ undershoot stair-step saccades to the BHF also significantly increased 14 days post training (0.67) as compared to pre-training (0.36).