Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Exp Eye Res. 2020 Mar;192:107926. doi: 10.1016/j.exer.2020.107926. Epub 2020 Jan 10.
The objectives of the present work were to assess by spectral domain optical coherence tomography (OCT) the changes in thickness of the outer nuclear layer (ONL), the ONL + photoreceptor inner segment (IS), and the retinal thickness, as a function of age in the normal canine retina. OCT retinal scans extending from the edge of the optic nerve head (ONH) along the superior and inferior meridians were captured in both eyes of 17 normal dogs at age ranging from 4 to 119 weeks. The different parameters along the superior and the inferior regions were determined following manual segmentation using the Heidelberg Eye Explorer software. Changes in thickness with age were modeled using one-phase exponential decay models. In vivo OCT imaging results showed no interocular statistically significant differences in ONL, ONL + IS, and retinal thickness at any age. All three parameters were however found to be statistically significantly thicker in the superior vs inferior retina. A rapid thinning of the three layers occurs in both the superior and inferior retina between 4 and 12 weeks of age, before reaching a plateau at around 20 weeks of age. In conclusion, the ONL, ONL + IS, and retinal thickness of the normal canine retina decrease significantly during the first three postnatal months, and is likely attributed to an overall increase in the eye volume and tangential dispersion of the photoreceptor since early photoreceptor developmental cell death is very limited at that age. Establishment of the natural history of ONL, ONL + IS, and retinal thinning will allow a more accurate assessment of the progression of a retinal degenerative condition as well as facilitate the detection of positive rescue effect of novel retinal therapies evaluated in this large animal model.
本研究旨在通过频域光学相干断层扫描（OCT）评估正常犬视网膜中外核层（ONL）、ONL+光感受器内节（IS）和视网膜厚度随年龄的变化。对 17 只正常犬的双眼进行了从视神经头（ONH）边缘沿上下子午线的 OCT 视网膜扫描，这些犬的年龄从 4 周到 119 周不等。使用 Heidelberg Eye Explorer 软件通过手动分割确定上下区域的不同参数。使用单相位指数衰减模型对厚度随年龄的变化进行建模。在任何年龄，活体 OCT 成像结果均显示双眼之间的 ONL、ONL+IS 和视网膜厚度无统计学显著差异。然而，所有三个参数在上部视网膜中均明显比下部视网膜厚。在 4 周至 12 周龄之间，上下部视网膜中的三个层均迅速变薄，然后在 20 周龄左右达到平台期。总之，正常犬视网膜的 ONL、ONL+IS 和视网膜厚度在出生后前三个月内显著减少，这可能归因于眼球体积的整体增加和光感受器的切向分散，因为在该年龄段，早期光感受器发育性细胞死亡非常有限。建立 ONL、ONL+IS 和视网膜变薄的自然史将有助于更准确地评估视网膜退行性疾病的进展，并促进对该大型动物模型中评估的新型视网膜治疗方法的阳性挽救效果的检测。
