What should be the starting point for retinal screening in patients diagnosed with type 2 diabetes?

The appropriate starting point for retinal screening in patients diagnosed with type 2 diabetes is at the time of diagnosis, not strictly tied to pregnancy unless the patient is pregnant. For pregnant women with pre-existing diabetes, the first trimester is a critical time to assess the health of the retina, given the increased risk for diabetic retinopathy during and after pregnancy. It is recommended to perform screenings each trimester as the risk for progression of diabetic retinopathy can increase due to changes in glycemic control often occurring during pregnancy.

For patients who are not pregnant, guidelines typically suggest that retinal screening should commence at the time of diagnosis of type 2 diabetes and be performed annually, although the frequency may vary based on findings at each examination. Immediate screening after achieving glycemic control might be beneficial but does not take precedence over the need for initial screening at diagnosis. Similarly, monitoring patients only after they exhibit symptoms of vision loss is not advisable, as many cases of diabetic retinopathy are asymptomatic in the early stages.

Thus, screening during pregnancy (option C) is essential for this population as part of a comprehensive management plan for diabetic patients.