These devices will help patients to read using binocular vision at a short reading distance.
For close reading binoculary. Power-range: 4 to 16. Visual field: >70º. Total weight: 26 – 34 gr. Working distances: 25 – 8cm. Test Sets: ML Bino Test sets available. These devices will help patients to read using binocular vision at a short reading distance. A magnified image is placed on the retina but as the addition is increased so the reading distance is reduced and the more the patient has to converge. The reading distance may become so short that the normal ability to converge is insufficient and as a result a double image will be seen. This can be resolved by using a prism “base-in” to assist natural convergence. There are a number of factors which must be taken into account when deciding whether or not to use these devices and these are described below. We will also try to indicate why an ML BINO 8 for instance will function in different ways for different patients. PD och CDThe position of the eye in relation to the optical centre (CD) of the lens will influence the amount of prism which the lens can create. An eye which looks through an optical plus lens with the optical centre nasal to the eye will create a prism base-in. The same principle applies in reverse. Consequently a patient with a large PD will have more prism base-in than a patient with a small PD. However a patient with a large PD will have to converge more in order to be able to read at the same distance as a patient with a small PD. In calculating the consequence of a large PD it is found that the positive effect is negated by the need for additional convergence. This is described further in the Appendix. With these devices there is no need to consider PD Cylinder and anisometropia. The greater addition the device creates the less influence an uncorrected cylinder normally have. Also smaller differences in power between R and L normally is more accepted from the patient when the addition is increasing. This is the reason why ML BINO standard is an easy solution. But it many times shows that the patient experiences a better function with his individual correction incorporated ML BINO could then easily be ordered with these specifications. The better image quality the incorporated correction of astigmatism and anisometropia could give the better it improves the reading time and the comfort reading distance. The reading distance has a clear influence on the function of the device because it is that distance which will affect how much prism is required. The reading distance will be dependent on the power of the device and the patient’s refractive error. Example: Patient A requires a base refraction of 3. A device of 8 gives an addition of 5 and a reading distance of 20 cm. Patient B requires a base refraction of -2. Here the device of 8 gives an addition of 10 with a reading distance of 10 cm. The diagram shows when according to the patients refractive error an ML BINO standard normally could be used. ML BINO 8 functions normally well at spherical refraction’s of ±0 and 2. For refractions outside the blue fields need of cylinder or differences R and L ML BINO Special should be considered. Ordering of ML BINO special to order an individual corrected ML BINO “ML BINO Special” do the following: 1. Specify the total power of the ML BINO Special. 2. Specify the obtained addition or the reading distance. With this information we are able to calculate and incorporate the correct prism the size of convergence aid. The purpose with these devices is to be able to have focus binoculary on a short distance with convergence aid. The table and the picture describe how much convergence-aid the incorporated prism gives in an ML BINO. The distance A describes focused object distance distance B describes where the eyes axis coordinates. Example: ML BINO 8 gives a focus distance of 12.5 cm for an emetropic person but the eyes convergence angle coordinates at a distance 21cm away. Dioptres Distance A Distance B 425.0cm35cm 520.0cm30cm 616.7cm25cm 812.5cm21cm 1010.0cm18cm 128.3cm15cm* 147.1cm12cm* 166.2cm10cm* * 14 and 16 is normally too strong as addition for an emetropic patient 12 is in the borderline. See recommendation in table 1 Prism. The prism is very precisely measured placed and edged into the frame. This is essential to avoid unwanted prism vertically which causes problems and discomfort for the patient. Filter and coating in order to improve the function and comfort even further the lenses could be coloured with any ML Filter and/or coated with our ML Prima the latest technology in hard and antireflexion treatment. Frames Halv 2The frames are of high quality in a modern design with spring hinges. The bridges are shaped for comfort. The front of the acetate-frame “Halv-2” and ”Halv-4” are in crystal to distract the patient as little as possible and the temples are coloured so that the system will be easy to find for someone with a visual impairment. The temple colour for “Halv-2” is brown and for “Halv-4” red blue black. The front of the metal frame ”Halv-3” is in antique silver and with black temples. The frames meet fully all the CE demands regarding nickel quality etc.. Halv 3 Halv 4 Lens materialAll lenses are manufactured in a CR-39 material with an aspheric frontcurve. From 7-8 it has a softlenti design in order to make the lenses as thin and cosmetically attractive as possible. ML Bino Bifo is a bifocal version of ML Bino. Bino Bifo enables binocular reading at shorter distances with two different additions. The upper section allows wearers to look at larger text and find their way around the page and the lower section is used for reading small print. The prisms in the different sections are accurately aligned to ensure greater prism in the lower section to compensate for the shorter reading distance!The correction limits for Bino Bifo standard are 3/ 6 or 5/ 8 in a semi-5 frame. Bino Bifo can also be custom-made to individual requirements. Addition range in the basic design: 3/ 6 or 5/ 8. Visual feld: 70°. Weight: 26-34 grams. Reading distance: 33 – 12 cm. Additional Options Available – Contact Us For Details. Halv-3 w 4 (40340) USD $111.08 Halv-3 w 6 (40360) $111.08 Halv-3 w 8 (40380) $111.08 Halv-3 w 10 (40300) $140.96 Halv-3 w 12 (40320) $140.96 Halv-4 black 4 (40440) $ 9981 Halv-4 black 6 (40460) $ 99.8 Halv-4 black 8 (40480) $ 99.82 Halv-4 black 10 (40400) $129.70 Halv-4 black 12 (40420) $129.70
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