1. OPTICAL DISPENSING

2. FRAMES  MATERIALS: –Cellulose acetate or zylate is the most commonly used material for plastic frames. Monel is a corrosion resistant alloy, and is the most prevalent material used for metal frames.

3. PLASTIC MATERIALS  Cellulose acetate  Cellulose propionate  Carbon fiber graphite  Polycarbonate  Polyamide  Optyl  Nylon

4. Cellulose acetate  Cellulose is mixture of cottonseed fibers, wood flakes, stabilizers and plasticizers. Zyl is east to adjust and has the unique ability to slightly reduce in size to accommodate a lens that is edged a bit small or to stretch to house a lens that is edged to large.

5. Cellulose propionate  Cellulose propionate is another plastic material used to produce injection molded frames. Because it is lightweight and very strong it lends itself well to the production of ultra thin and over sized frame styles.

6. Carbon fiber graphite  CFG is a light weight materials (about one forth the weight of zyl and metal) that consists of a carbon compound and a textiles fiber called ceramic whisker.

7. Polycarbonate  It is used in the manufacturing of bullet proof glass and crash helmets. In eye care it is used for sports and safety purposes.

8. Polyamide  Polyamide is a type of nylon that is very strong and light weight in nature. It is easily tinted and is available in a wide range of colors.

9. Nylon  It is a virtually unbreakable, hypoallergenic frame materials that in today's market, is mostly used for injection molded sun glasses as well as men’s frame styles.

10. Optyl  It is a plastic frame materials that is hypoallergenic, light weight, and keeps its finish over time. It is a lasting durable material known for returning to its original shape when thoroughly heated.

11. METAL FRAME MATERIALS  Monel  Nickel  Nickel –Silver  Phosphorous bronze  Stainless steel  Titanium  Aluminum  Beryllium  Cobalt

12. Monel &Nickel  Monel is a combination of nickel and copper. It is a strong stable material that also lends itself to making nose pad arms, bridges and end pieces.  Nickel is a strong and generally bends without breaking to making nose pad arms. Patients are sometimes allergic to this products.

13. Nickel-silver & phosphorous  NS is a strong rigid material that is suitable for hinges, end pieces, bridges and decorative trims. This is brittle material.  Also called phosphor-bronze is an alloy comprised mostly of copper. Adjustments can be a problem because of the “springy” characteristics of the material.

14. Stainless-steel & Titanium  It is very popular because this material is strong even in thin streamlined applications. This metal is alloy comprised of manganese, nickel, iron and chromium.  Titanium is a naturally occurring element that is highly corrosion-resistant and is incredibly lightweight. If the wearers allergic to other metals and is purchasing a titanium frame to avoid allergic skin reactions.

15. Aluminum, beryllium & cobalt  Aluminum is very popular. This make it even lighter than titanium, it is rigid material that is difficult to adjust.  Beryllium is used in the production of temples by combining with other metals. It is very expense.  Cobalt offers a highly polished finished and is often used in thin frame designs. It is also expensive.

16. Types of frame  Full frame  Combination frame  Semi-rimless  Full rimless (or) Drill mount  Half eye

17. Frames

18. Frame parts  Frame front The frame front has either a sculpted bridge or a bridge device that is attached to the frame. The bridge is an important part of the frame because it connects the two eye wires and it supports most of the weight of the spectacles on the patients nose.

19. Frame part

20. Bridge type  Plastics: –Saddle, modified saddle, keyhole, adjustable bridge.  Metal : Adjustable nose pad, uni – fit bridge, saddle bridge

21. Nose pad

23. Temples  There are five temple design used in frame manufacturing Skull temples Library temples Convertible temples Comfort cable temples Riding bow temples

24. Temples

25. Frame selection  The best frame for a patient complements his or her facial structure, requires minimal adjustments, and will securely hold the lenses in place.

26. Frame styling  The size and the shape of the frame greatly affect the overall cosmetic appearance of the finished prescription lenses. The best way to control the finished look is to first imagine the thickness and curves of the lenses.

27. Determining facial wrap  There are seven facial shapes: –Oval –Triangle –Round –Long –Square –Inverted triangle –Diamond

28. Frame selection

29. Frame types vs. facial proportions  Oval shape faces - any frame shape  Round face - angular frames  Square face - round or oval shape  Long face - deep vertical frame  Triangle }  Inverted triangle } oval or rounded.diamond face }designs.

30. LENSES

31. Abbe value  The abbe value (first describe by Ernest k. abbe a German optical physicist) indicates the ability of a lens material to purely refract white light without chromatic aberration.

32. Abbe value of common lens materials.  MATERIAL Glass, crown CR 39 Spectralite High index 1.56 (resin) High index 1.60 (resin) High index 1.66 (resin) Polycarbonate High index glass INDEX –59 –58 –47 –39 –37 –32 –31 –25

33. Lens types  Lenses are classified as spheres, cylinder and prisms.

34. Lens material  CR-39  Glass  Transitions  High index lenses  Polycarbonate

35. Lens designs  Single vision lenses  Bifocals  Trifocals  Occupational segments  Progressive  Corrective curve lenses  Aspherics  Lenticular bowl  Blended myodisc  Safety lenses  Slab off prism

36. Bifocals

37. Single vision lenses  Single vision lenses correct vision for one focal length. (focal length is the distance at which the lens focuses an object that is 1 meter away from the lens). They could be prescribed for distance vision only or for near vision only.

38. Bifocals  Bifocal lenses correct vision at two distances, usually with a prescription for distance vision at the top of the lens and a segment at the bottom of the lens for close work.  Bifocal segments are available in many designs and sizes. There are round segments called kryptok bifocals as well as flat top.  Round segments are available in 22 – 24mm sizes and flat top bifocals are made in 25,28 or 35 mm sizes.

39. Trifocals  Trifocal lenses have three viewing distances or segments. A conventional trifocal lens has a distance portion and intermediate segment and a bottom segment to correct vision at 33 cms.  Trifocal lenses can be prescribed to correct vision at varying distance.

40. Trifocals

41. Progressive addition lenses (PAL)  PAL consists of distance, intermediate and near zones. They cause less of an image jump than lined segments because the power differences between the zones are achieved thorough slight, gradual changes in power, unlike that of conventionally lined bifocals or trifocal. PAL are sometimes called bifocals but in actuality perform most like trifocals because they offer an intermediate area.

42. PAL lens

45. Corrective curve lenses  A lens which could produce the same quality of vision through the periphery as through the optic center of the lens would need have a radius that corresponded with the radius of the moving eyeball.

46. Corrective curve lens

47. Aspherics  Aspheric lenses improves the peripheral optics and the cosmetic appearance of the lenses. The curvature of an aspheric design change in the outer portion of the lens. This is especially true with mid-to high-powered lenses.

48. Aspheric lens

49. Aphakic lenses  Cataract lenses are aspheric lenses that are available as lenticular design. This means a minus lenticular carrier is used to house the high powered plus prescription. They should be fit as a close to the eye as possible in order to provide a wide field of vision for the patient.

50. Aphakic lens

51. Blended myodisc  A myodisc or blended myodisc lens is used for patients who have very high myopia. It is a lenticular lens with a carrier, and produce a clear central area for vision with a significantly thinner lens edge. It is available from -12.0 D  Another lens for high myopes is the biconcave lens. This lens is concave and ground on both the front and back surface, resulting in an overall thinner and lighter weight lens.

52. Myodisc

53. Safety lenses –Special purposes lenses must also have an “S” marked on the lenses to signify that the lenses are for special purpose. An example of special purpose occupational lenses would be those that are needed by welders. Productive lenses for someone in this occupation must have a filter that guards the welder from damaging optical radiations.

54. Safety lenses

56. Slab off prism  This is given for anisometropic patients. If one eye having a plus correction and the other eye having a minus correction often needed glasses with a specially ground lens treatment called slab off.

57. Slab of prism