Amiodarone-associated optic neuropathy (AAON) is a complex clinical diagnosis, requiring distinction from non-arteritic ischemic optic neuropathy (NAION) due to a shared at-risk patient population. Diagnosis of AAON is complicated by a varied clinical presentation and incomplete pathophysiologic mechanisms. This article reviews pertinent literature for describing and clinically delineating AAON from NAION, as well as newly reported protective mechanisms of insulin-like growth factor 1 (IGF-1) and PI3K/Akt against amiodarone-induced oxidative and apoptotic injury in retinal ganglion and pigment epithelial cells. These studies offer a basis for exploring mechanisms of amiodarone toxicity in the optic nerve.

Age-related macular degeneration (AMD) is a leading cause of irreversible blindness world-wide. We recently reported that polyethylene glycol (PEG) can activate the alternative pathway of the complement system and induce choroidal neovascularization (CNV) in mice. Currently, no other investigator has demonstrated CNV after PEG injection in the mouse eye. The aim of this article is twofold: we review the histologic changes in mouse retina and retinal pigmented epithelium (RPE) after treatment with PEG, and we summarize a model of wet and dry AMD pathogenesis in mice through subretinal PEG treatment of RPE cells and retinal layers. We injected (subretinal) male C57BL/6 mice with 2 μL of solution containing 0.5 mg and 1.0 mg of PEG or PBS in control groups. Eyes were harvested at day 1, 3 and 5 after injection and processed for analysis. Sections were immunohistochemically stained for complement component C3, mem-brane attack complex (MAC), and cytokeratin 18. Light and laser confocal microscopy was used for image capturing. PEG increased deposition of C3 and MAC on RPE cells and on all retinal layers after 1.0 mg injection. PEG induced loss of cellular contacts between RPE cells and migration of RPE cells in the subretinal space at day 1 after PEG injection. After 0.5 mg PEG injection, increased size of RPE cells was detected at day 3 and 5. Apoptotic bodies were observed in outer nuclear layer at day 3 and 5 after 0.5 mg PEG treatment. RPE cells with dark cytoplasm and condensed chromatin were observed. Higher doses of PEG induce CNV, encouraged RPE cell proliferation and death, and damage photoreceptors in mice. This simple and fast model may be useful to explore the pathogenesis of both dry and wet AMD.