ANSI Z80.11:2007 pdf download.Laser Systems for Corneal Reshaping.
3.26 Astigmatism, compound myopic: Occurs when both focal lines (far lines) are in front of
the retina, resulting in a refraction that can be expressed as two minus cylinders (cross cylinder
form, e.g.. -1.00 x 180° & -2.00 x 90°) or a sphere and a cylinder (spherocylindrical form. e.g., –
1.00 DS -1.00 IX x 90°).
3.27 Astigmatism, mixed: Occurs when one focal line (far line) is in front of the retina and one focal line (far line) is behind the retina, resulting in a refraction that is myopic in one meridian and hyperopic in the orthogonal meridian. The resulting refraction can be written in cross cylinder form with one positive cylinder and one negative cylinder (e.g.. +1.00 x 90° & – 1.00 x 180°), in plus sphcrocylinder form (e.g.. -1.00 DC +2.00 DC x 900). or in minus sphcrocylinder form (e.g.. +1.00 DS -2.00 DC x 180°).
3.28 Astigmatism, simple hyperopic: Occurs when one focal line (far line) is on the foveola and the other focal line (far line) is behind the retina, resulting in a refraction that is pIano in one meridian and a plus cylinder in the orthogonal meridian (e.g.. 0.00 DS +1.00 DCx 90°).
3.29 Astigmatism, simple myopic: Occurs when one focal line (far line) is on the foveola and the other focal line (far line) is in front of the retina, resulting in a refraction that is pIano in one meridian and a minus cylinder in the orthogonal meridian (e.g.. 0.00 DS -1.00 DC x 90°).
4 Mechanical, thermal, and environmental requirements
This section applies to the mechanical, thermal, and environmental requirements of the laser.
4.1 Combination of different devices
If the laser system device is intended for use in combination with another instrument, the connecting system shall not impair the specified performance of either instrument. Sufficient objective evidence should be obtained either from testing and/or analysis to demonstrate that the laser system fulfills the requirements of this standard when said other devices are connected.
For coupling with active ophthalmic insruments. the electromagnetic compatibility provisions of IEC 60601-1-2 shall apply.
4.2 Materials
Materials shall meet the safety requirements of IEC 60601-1 -1 for medical electrical systems.
4.3 Resistance to transport and storage conditions
After exposure of the laser system in its original packaging to the range of transport and storage conditions, within the temperature and humidity range given below and any other environmental conditions specified in the user instructions, the laser system shall conform to all safety, optical. and mechanical requirements under the environmental conditions specified in the user instructions for clinical use.
Temperature range: -10° C to +55° C.
Humidity range: 10% to 95% relative humidity (noncondensing)
5.6 Electrical safety
The manufacturer shall complete testing and certify that the device conforms to IEC 60601-1-1.
5.7 Radiation safety
The manufacturer shall complete testing and certify that the device complies with 21 CFR
1040.10 and 1040.11 (or the equivalent requirements of IEC 60825-1 and IEC 60601-2-22).
5.7.1
Light hazards
Measures shall be taken to ensure that llumination levels that reach the retina (ie,, due to aiming beams, fixation lights, microscope ilumnination, or secondary radiation from the treatment beam) are held as low as possible. Ilumination levels for the operation microscope shall conform to the limits set by ISO 10936-2 and for other illumination sources to the limits for non-exempt instruments set by ISO 15004-2.
5.8 Gas safety (for gas lasers)
For systems using gas (e.g.. excimer lasers), the laser system shall have an appropriate means of containment, control, and evacuation of any gases used to perform the intended function(s) in conformance with the user instructions. The gas containment system shall be designed such that the risk of physical injury when using this instrument is reduced as much as is practical.
The use, storage, and maintenance of any gases used to perform the intended function(s) shall conform to applicable environmental and occupational requirements. All pressurized gas bottles used with the product shall be housed in hermetically sealed containment devices or be built into a structure that shall prevent accidental release of toxic and or high pressure gas. If customer access to the fluorinated gas (ie. customer can change the pre-mix gas bottle) is provided, there shall be a suitable fluorine detector/alarm provided to indicate automatically if the concentration of fluorine exceeds 0.1 ppm, the maximum permissible exposure limit for an eight-hour exposure.
