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

最常见的是通过测量观察者的视觉敏锐度来评估视觉功能，也就是最小的可识别的视标--通常是字母。这一过程受到眼睛的光学质量和采集视网膜图像的神经结构的限制。然而，另一种视觉分辨率--超敏锐度--的存在超过了传统的敏锐度，从而表明视觉能力受到视网膜电路和大脑神经机制的强烈影响。超敏锐知觉的测量比经典的视觉分辨率测试有一些优势，因为它主要涉及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，但超敏感度背后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的视锥目标视网膜位置传递视觉刺激。我建议在单个视网膜光感受器的水平上研究超急性知觉的机制，以揭示空间视觉任务背后的离散视网膜连接。为了区分纯视网膜和超急性敏感度的中枢方面，所有实验也将在弱视受试者中进行，即患有神经视力下降的受试者。最后，将设计程序，促进超急性测量在标准眼科检查中的使用。超视力测试可能提供鉴别诊断早期神经性视力丧失的可能性，这是传统视力测试所不可能实现的。

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.