*2.3. Spectral-Domain Optical Coherence Tomography*

Spectral-domain optical coherence tomography (SD-OCT) (840 nm; Bioptigen, Inc./Leica, Durham, NC, USA) was used to obtain in vivo images of the retina at one, two, and three months of age. OCT images were collected with Bioptigen InVivoVue® 1.4 software and Bioptigen Diver® 2.0 software was used to analyze outer nuclear layer (ONL) thickness and full retinal thickness (F.R.T.) across all retinal layers at five eccentricities spanning two-thirds of the retina centered at the optic nerve head. A detailed description of this procedure has been reported previously [22]. F.R.T. was calculated from the difference of markers 1 and 10 and ONL thickness was calculated from the difference between 5 and 6.

### *2.4. Fundus Examination and Fluorescein Angiography*

Fundus examination was performed with a Micron IV digital fundus microscope (Phoenix Technology Group, Pleasanton, CA, USA), using the mouse objective and hydroxypropylmethyl cellulose 2.5% on the surface of the cornea. Digital images of the fundus were captured with dedicated StreamPix® 6 digital software (NorPix, Inc., Montreal, Quebec, Canada) and processed using Adobe® Photoshop® 6 (Adobe Systems, Inc., San Jose, CA, USA).
