An endoscope comprising: a cannula for inserting into a patient's body; one and only one cover (214, 714, 1014) made from a transparent or translucent material that extends over an entire distal end of the cannula, wherein the cover (214, 714, 1014) has an outer surface (217, 716) and an inner surface (215, 718), opposite the outer surface (217, 716); a light source (210, 710) inside the cannula configured to deliver light into the cover(214, 714, 1014), at least some of which passes through the cover (214, 714, 1014) to illuminate an inspection site inside the patient's body; and an imaging system (212, 712) inside the cannula configured to receive light that has been reflected off the inspection site in the patient's body and returned to the endoscope through the cover (214, 714, 1014); wherein, during operation, a portion of the light that is delivered by the light source (210, 710) into the cover (214, 714, 1014) is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) to travel back toward the inner surface (215, 718) of the cover (214, 714, 1014); characterised in that a portion of the cover (214, 714, 1014) in front of the imaging system (212, 712) is thicker than a portion of the cover (214, 714, 1014) in front of the light source (210, 710); and wherein the light source (210, 710), the cover (214, 714, 1014), and the imaging system (212, 712) are configured relative to one another such that none of the light that is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) and travels back toward the inner surface (215, 718) of the cover (214, 714, 1014) reaches an optical input of the imaging system (212, 712) directly, that is, without being further internally reflected; and wherein a) an angle at which the light is delivered by the light source (210, 710) into the cover (214, 714, 1014), b) a thickness of the portion of the cover (214, 714, 1014) in front of the imaging system (212, 712), c) a thickness of a portion of the cover (214, 714, 1014) in front of the light source (210, 710), and d) a distance between an optical exit of the light source (210, 710) and the optical entrance of the imaging system (212, 712), are configured to prevent the light that is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) and travels back toward the inner surface (215, 718) of the cover (214, 714, 1014) from reaching an optical input of the imaging system (212, 712) directly off of the internal reflection. a cannula for inserting into a patient's body; one and only one cover (214, 714, 1014) made from a transparent or translucent material that extends over an entire distal end of the cannula, wherein the cover (214, 714, 1014) has an outer surface (217, 716) and an inner surface (215, 718), opposite the outer surface (217, 716); a light source (210, 710) inside the cannula configured to deliver light into the cover(214, 714, 1014), at least some of which passes through the cover (214, 714, 1014) to illuminate an inspection site inside the patient's body; and an imaging system (212, 712) inside the cannula configured to receive light that has been reflected off the inspection site in the patient's body and returned to the endoscope through the cover (214, 714, 1014); wherein, during operation, a portion of the light that is delivered by the light source (210, 710) into the cover (214, 714, 1014) is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) to travel back toward the inner surface (215, 718) of the cover (214, 714, 1014); characterised in that a portion of the cover (214, 714, 1014) in front of the imaging system (212, 712) is thicker than a portion of the cover (214, 714, 1014) in front of the light source (210, 710); and wherein the light source (210, 710), the cover (214, 714, 1014), and the imaging system (212, 712) are configured relative to one another such that none of the light that is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) and travels back toward the inner surface (215, 718) of the cover (214, 714, 1014) reaches an optical input of the imaging system (212, 712) directly, that is, without being further internally reflected; and wherein a) an angle at which the light is delivered by the light source (210, 710) into the cover (214, 714, 1014), b) a thickness of the portion of the cover (214, 714, 1014) in front of the imaging system (212, 712), c) a thickness of a portion of the cover (214, 714, 1014) in front of the light source (210, 710), and d) a distance between an optical exit of the light source (210, 710) and the optical entrance of the imaging system (212, 712), are configured to prevent the light that is internally reflected at the outer surface (217, 716) of the cover (214, 714, 1014) and travels back toward the inner surface (215, 718) of the cover (214, 714, 1014) from reaching an optical input of the imaging system (212, 712) directly off of the internal reflection.