Spencer Center for Vision Research, Byers Eye Institute at Stanford University, Palo Alto, California, United States.
Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States.
Invest Ophthalmol Vis Sci. 2024 Oct 1;65(12):45. doi: 10.1167/iovs.65.12.45.
Concussed adolescents often report visual symptoms, especially for moving targets, but the mechanisms resulting in oculomotor deficits remain unclear. We objectively measured accommodative and vergence responses to a moving target in concussed adolescents and controls.
Thirty-two symptomatic concussed participants (mean age, 14.4 ± 2.6 years; mean days since concussion, 107 days; range, 36-273 days) and 32 healthy controls (mean age, 12.7 ± 2.1 years) viewed a movie binocularly (closed-loop) and monocularly (vergence open-loop), as well as a Difference of Gaussians (DoG) target binocularly (accommodation open-loop). The movie or DoG target sinusoidally moved toward and away from participants at a 0.1-hertz (Hz) frequency at four separate stimulus amplitudes (1.50 diopters [D], 1.00 D, 0.50 D, 0.25 D) around a 2.50-D midpoint. Accommodation and vergence were continuously measured at 50 Hz using the PowerRef 3. Fourier analysis was used to assess the response amplitudes at the 0.1-Hz frequency. A 2 × 3 analysis of variance with the factors group (concussed, control) and viewing condition (binocular, monocular, DoG) was conducted on response amplitudes.
Across groups, accommodative and vergence responses were significantly higher in binocular than monocular conditions (P < 0.001), but not DoG conditions. Compared to controls, concussed participants had significantly reduced monocular accommodative responses (P < 0.012; e.g., at 1.50 D, controls = 1.09 ± 0.47 D and concussed = 0.80 ± 0.36 D, P = 0.011). No group differences were observed for vergence responses in any viewing condition.
Accommodative and vergence responses to the moving target were largely driven by disparity cues for both groups, with only minimal improvements in the presence of additional blur cues. Concussed participants showed reduced accommodative responses to a 0.1-Hz stimulus in monocular conditions, indicating mild accommodative deficits in the absence of disparity cues.
患有脑震荡的青少年经常报告视觉症状，尤其是在观察移动目标时，但导致眼动缺陷的机制仍不清楚。我们客观地测量了患有脑震荡的青少年和对照组在观察移动目标时的调节和聚散反应。
32 名有症状的脑震荡参与者（平均年龄 14.4 ± 2.6 岁；平均脑震荡后天数 107 天；范围 36-273 天）和 32 名健康对照组（平均年龄 12.7 ± 2.1 岁）分别双眼（闭环）和单眼（聚散开环）观看电影，以及双眼（调节开环）观看差分高斯（DoG）目标。电影或 DoG 目标以 0.1 赫兹（Hz）的频率在四个不同的刺激幅度（1.50 屈光度[D]、1.00 D、0.50 D、0.25 D）下围绕 2.50-D 中点向参与者方向和远离方向正弦运动。使用 PowerRef 3 以 50 Hz 的频率连续测量调节和聚散。傅里叶分析用于评估 0.1-Hz 频率下的响应幅度。对组（脑震荡、对照组）和观察条件（双眼、单眼、DoG）的因素进行了 2×3 方差分析。
在所有组中，双眼条件下的调节和聚散反应明显高于单眼条件（P < 0.001），但在 DoG 条件下没有差异。与对照组相比，脑震荡组的单眼调节反应明显降低（P < 0.012；例如，在 1.50 D 时，对照组= 1.09 ± 0.47 D，脑震荡组= 0.80 ± 0.36 D，P = 0.011）。在任何观察条件下，两组的聚散反应均无差异。
调节和聚散反应对移动目标的反应主要由两组的视差线索驱动，只有在存在额外模糊线索的情况下才有轻微改善。在单眼条件下，脑震荡组对 0.1-Hz 刺激的调节反应降低，表明在没有视差线索的情况下存在轻度调节缺陷。
