The unique optomap ultra-widefield view helps your eye care practitioner detect early signs of retinal disease more effectively and efficiently than with traditional eye exams. Early detection means successful treatments can be administered and reduces the risk to your sight and health.
An electron dot diagram is a method of writing the chemical symbol of an element by surrounding it with dots to indicate the number of valence electrons. Valence electrons are found in an atom's outer shell and are the ones involved in chemical reactions.
The circle with the arrow means male, and the circle with the plus sign means female. the circle with a plus-sign is used as the zodiacal symbol for the planet Venus. It is the female and male sign. the one in your question with the top pointing up is male, and the one with the cross pointing down, is female.