Once this type of retinal detachment develops and causes symptoms, it can progress to total blindness if it is not repaired promptly. In the United States, retinal detachment is a relatively uncommon condition, affecting only one of every 10,000 Americans each year.
Gas exchange in reptiles still occurs in alveoli however, reptiles do not possess a diaphragm. Thus, breathing occurs via a change in the volume of the body cavity which is controlled by contraction of intercostal muscles in all reptiles except turtles.
Quick Answer. Gaseous exchange occurs in the alveoli by simple diffusion. The blood flowing past the alveoli is rich in carbon dioxide and very poor in oxygen. The gas molecules naturally flow in the direction of lower concentration through the thin gas exchange membrane, which is only two cells thick.