Anti-radiation missile as the longer the radar is off (and assuming it never turns back on), the more error is introduced into the missile's course. The ALARM even has an added loiter mode, with a built in parachute, enabling it to descend slowly until the radar lights up, when the rocket motor will re-ignite. Even a temporary shut down of the enemy's missile guidance radar can be of a great advantage to friendly aircraft during battle. The DRDO Anti-Radiation Missile is under development by India. The MAR-1 is under development by Brazil. Several surface-to-surface missiles, like the P-700 Granit, P-500 Bazalt, MM40
Subjective refraction Subjective refraction Subjective Refraction is an attempt to determine, by trial and error using the patient’s cooperation, the combination of lenses that will provide the best corrected visual acuity (BCVA). It is a clinical examination used by orthoptists, optometrists and ophthalmologists to determine a patient's need for refractive correction, in the form of glasses or contact lenses. The aim is to improve current unaided vision or vision with current glasses. Glasses must also be comfortable visually. The sharpest final refraction is not always the final script the patient wears comfortably. The following equipment is used to complete a Subjective Refraction: