During which trimester of pregnancy are ocular structures most susceptible to damage from teratogens?

The first trimester of pregnancy is the most critical period for the development of ocular structures and is characterized by rapid cell division and differentiation. During this time, the foundational elements of the eyes, including the lens, retina, and optic nerve, are forming. Teratogens, which are substances that can cause developmental abnormalities, pose the highest risk during these early stages when organogenesis occurs. Exposure to harmful agents, whether they are pharmaceuticals, environmental toxins, or infections, can lead to significant and lasting damage to developing ocular structures.

As pregnancy progresses into the second and third trimesters, the major organs are already formed, and while exposure to teratogens can still have adverse effects, the risks to ocular structures are less pronounced compared to the early developmental stages. Hence, the first trimester stands out as the most critical and vulnerable period for the potential impact of teratogens on eye development.