ISO 10343-2014 pdf free download

ISO 10343-2014 pdf free download.Ophthalmic instruments Ophthalmometers Instruments ophtalmiques-Ophtalmometres.
3.5
keratometric constant
conversion value equal to 337,5 used to convert corneal curvature from inverse millimetres (mmi) to keratometric dioptres
[SOURCE: ISO 19980:2012,3.111
3.6
keratometric dioptres
KD
value of curvature, expressed in inverse millimetres (mm’), multiplied by the keratometric constant
337,5
[SOURCE: ISO 19980:2012, 3.12]
4 Requirements
4.1 General
The ophthalmometer shall conform to the requirements specified in ISO 150044.
4.2 Radius of curvature measurements
The ophthalmonwter shall conform to requirements given in Table 1 or Table 2. Conformity shall be verified as described in 52. If the instrument conforms to the requirement of TahI1 it is a “Type B” ophthalmometer. If the instrument conforms to the requirements of Tablel it is a 9’ype A ophihalmometer. Type A and Type B ophthalmometers have sufficient resolution and range to adequately measure human corneas. Type A ophthalmometers have sufficient resolution and range (see Table 2) to adequately measure the radii of curvature of contact lenses complying with ISO 18369-3:2006,4.1.3, and Clause 5. It Is assumed that the local corneal front surface and both contact lens surfaces are spherical or toroidal.
4.4 Eyepiece adjustment (if applicable)
The dioptric adjustment range for distance-dependent Instruments shall be a minimum of-4 D to +4 D.
for which the scale from —3 0 to +2 D shall be calibrated.
5 Test methods
5.1 General
All tests described in this International Standard are type tests.
5.2 CheckIng optical requirements
Conformity to the requirements specified in 4,2 and 43 shall be verified by use of measuring devices the measuring error of which is less than 10 % of the smallest value to be determined.
Test results shall be evaluated according to the general rules of statistics.
Conformity to the requirements of 42 shall be verified using three spherical test surfaces, one chosen from each of three radii ranges: ≤6,8 mm, 7,5 mm to 8,1 mm and 9,1 mm. These test surfaces shall have the following properties:
a) uncertainty of sphere radius of curvature 1 pm;
b) local departure from sphericity 0.5 pm;ISO 10343-2014 pdf free download.