Probing retinal and neural mechanisms of vision by hyperacute optical stimulation of single photoreceptor cells

视觉功能最常通过测量观察者的视敏度来评估，即最小的视标-通常是字母-刚好可以识别。这个过程受到眼睛的光学质量和对视网膜图像进行采样的神经结构的限制。然而，另一类视觉分辨率-超敏度-存在超过常规敏锐度，从而证明视觉能力受到视网膜回路和大脑神经元机制的强烈影响。超急性感知的测量提供了一些优于视觉分辨率的经典测试，因为它主要解决了观察者视觉能力的神经部分。虽然游标敏锐度在神经科学中得到了很好的研究，但超急性感知的确切视网膜和神经机制尚不清楚。光学刺激和视网膜成像的最新进展使得现在可以在活体人眼中的视锥靶向视网膜位置处递送视觉刺激。在这里，我建议在单个视网膜光感受器水平上研究超急性感知的机制，以揭示空间视觉任务背后的离散视网膜布线。为了区分超急性敏感性的纯视网膜方面和中心方面，所有实验也将用弱视受试者，即患有神经视敏度降低的受试者进行。最后，将设计程序，促进在标准眼科检查中使用超急性测量。超敏度测试可以提供鉴别诊断早期神经视力丧失的可能性，这是传统视力测试无法实现的壮举。

Visual function is most frequently assessed by measuring the observer’s visual acuity, i.e. the smallest optotypes – usually letters – that are just identifiable. This process is limited by the optical quality of the eye and the neural structures that sample the retinal image. However, another class of visual resolution – hyperacuity – exists that surpass conventional acuity, thereby demonstrating that visual capabilities are strongly influenced by retinal circuitry and the neuronal machinery of the brain. The measurement of hyperacute perception offers a few advantageous over classical tests of visual resolution, since it primarily addresses the neural fraction of the observer’s visual capabilities. Although vernier acuity is well-studied within the neurosciences, the exact retinal and neural mechanisms underlying hyperacute perception are unknown. Recent advances in optical stimulation and retinal imaging makes it now possible to deliver visual stimuli at cone-targeted retinal locations in the living human eye. I here propose to study the mechanisms of hyperacute perception at the level of single retinal photoreceptors to uncover the discrete retinal wiring underlying spatial vision tasks. To distinguish pure retinal from central aspects of hyperacute sensitivity, all experiments will also be carried out with amblyopic subjects, i.e. subjects who suffer from decreased neural visual acuity. Finally, procedures will be engineered that promote the use of a hyperacute measurement in standard ophthalmic examination. Hyperacuity tests may offer the possibility to differentially diagnose early neural vision loss, a feat that is not possible with conventional acuity testing.