The invention is directed to substituted indoline derivatives. Specifically, the invention is directed to compounds according to Formula I: wherein R1, R2, and R3 are defined herein. The compounds of the invention are inhibitors of PERK and can be useful in the treatment of cancer, ocular diseases, and diseases associated with activated unfolded protein response pathways, such as Alzheimer's disease, stroke, Type 1 diabetes Parkinson disease, Huntington's disease, amyotrophic lateral sclerosis, myocardial infarction, cardiovascular disease, atherosclerosis, and arrhythmias, and more specifically cancers of the breast, colon, pancreatic, and lung. Accordingly, the invention is further directed to pharmaceutical compositions comprising a compound of the invention. The invention is still further directed to methods of inhibiting PERK activity and treatment of disorders associated therewith using a compound of the invention or a pharmaceutical composition comprising a compound of the invention.