what are those round metal things that doctors wear on their heads?

"Those 'round metal things' that you see doctors wear on their heads are called "headlamps" or "surgical lighting lamps". They are primarily used during surgical procedures to provide adequate lighting for the doctor or surgeon.

Headlamps are composed of a series of LED or halogen bulbs that provide intense, focused lighting. Most headlamps are adjustable in terms of brightness and angle, so that the doctor or surgeon can adjust the lighting to suit the specific needs of the procedure.

These lamps are mounted on an adjustable head, so that they can be easily positioned to illuminate the working area. Most headlamps are powered by rechargeable batteries or an external power source, so that they can be used in environments where there is no access to electrical power.

Headlamps are used in a wide range of surgical procedures, including general surgery, cardiothoracic surgery, vascular surgery, orthopedic surgery, neurosurgery, plastic surgery, and ophthalmologic surgery. In addition, headlamps are also used in other medical procedures such as endoscopy and diagnostic imaging.

Modern headlamps are equipped with advanced technologies such as UV ray filtering and color temperature regulation, allowing for suitable lighting without causing damage to the retina or skin of the patient, and reducing visual fatigue of the doctor or surgeon.

Furthermore, the use of headlamps contributes to creating a safer and more precise surgical environment, as they provide adequate lighting for visualization of tissues and anatomical structures, allowing the doctor or surgeon to make an accurate assessment of the area to be treated and perform the procedure in a more precise and safe way.

In summary, headlamps are an essential medical equipment used during surgical and medical procedures to provide adequate lighting for the doctor or surgeon."