What limits visual acuity in patients with infantile nystagmus? (360G-Wellcome-211740_Z_18_Z)

We hypothesize that the visual acuity is limited in patients with infantile nystagmus due to the arrested retinal development and nystagmus characteristics. The main research question is to investigate the combined effects of retinal development and nystagmus characteristics on the visual acuity of patients with infantile nystagmus. Specifically we will quantify retinal development by grading optical coherence tomograms using a foveal hypoplasia grading system developed at Leicester. Additionally, we will segment the intra-retinal layers at the fovea to derive thicknesses measurements including the cone outer segment thickness which is a surrogate marker for cone photoreceptor spacing. Nystagmus characteristics such as intensity, eye velocity and eXpanded Nystagmus Acuity Function (NAFX) will be calculated from eye movement recordings. A mixed model will be used to determine the level of contribution of each of these factors to the visual acuity of patients with infantile nystagmus. Understanding the contributory factors to reduced visual acuity in nystagmus will help determine therapeutic strategies to improve vision and provide prognosis for patients.