What are the differences between thinning of the retina & lattice degeneration?

They are the same: Lattice degeneration is a thinning of the peripheral retina from the vitreous gel "pulling" on the retina with a distinctive whitening of the retinal blood vessels. This forms an oval or round patch of "lattice" white blood vessels and a thinned retina. Lattice can be associated with round retinal holes from the thinning and retinal tears at the edge-this can result in retinal detachment.