If you are coming from a country with Yellow fever, then you might have to provide a vaccination certificate for that. Besides that, a medical test for an Oman visa is not mandatory for everyone. In case of a required medical test, you need:

1. Blood tests
2. HIV
3. Syphilis
4. Hepatitis B&C
5. Urinalysis
6. Chest X-ray.

Ensure that the website is transparent, stating their non-affiliation with the Government. Further, if there is a clearly stated service fee. In addition to that, customer feedback and reviews also can assure you of their authenticity.

There is no age restriction for Oman tourist visa.

Yes, Eritrea citizens can apply for and obtain an Oman visit visa.