ophthalmic lenses


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ophthalmic lenses

  1. 1. Ophthalmic Lenses
  2. 2. Injuries from ophthalmic lenses are asignificant source of liability claimsagainst optometrists.The most likely cause of injury isbreakage of a glass, high index, or allylresin (CR-39) lens.Frames are a less likely cause oflitigation, but “safety” and sportsframes have been involved in liabilityclaims.
  3. 3. Liability claims most frequently allegenegligence, but product liability may bealleged if lenses or frames are “defective”.For an optometrist, there are three typesof negligence claims involving lenses:1--failure to prescribe an impact- resistantlens material2--failure to warn of limited impactresistance3--failure to inspect lenses
  4. 4. The materials of choice with respect toimpact resistance are polycarbonate andTrivex.Trivex is lighter thanpolycarbonate, morescratch resistant,has comparable uvattenuation,and hassimilarimpactresistance.
  5. 5. The key error is failure to prescribepolycarbonate plastic (or Trivex) whenprotection is a key clinical consideration; thepatients for whom protection is necessaryinclude:• Monocular persons• Athletes• Workers whose occupations place them at special risk for injury (e.g., police)• Children• Individuals with compromised corneas (e.g., RK, LASIK, penetrating keratoplasty)
  6. 6. A policeman was struck by a drunk as he wasentering a bar for a routine investigation. Theblow shattered his spectacles, causing a pieceof glass to be driven into an eye, therebycreating a permanent loss of acuity. He suedboth the optical company filling theprescription and the optician dispensing thespectacles, alleging they were negligent forfailing to provide him with lenses that wereeither more impact resistant or less likely tocome out of the frame in sharp, jagged pieces(i.e., plastic lenses). A sizable judgment wasreturned in his favor.
  7. 7. The second error is failure to warnpatients of the limited impact resistanceof ophthalmic materials other thanpolycarbonate (i.e., glass, allyl resin(CR-39), high index).This warning is especially importantwhen a secondary use (e.g., playingbaseball) makes wear of the lens materialhazardous.
  8. 8. Example case: injury from shatteredspectacle lens• Myopic, physically active man in his 20s needs new glasses• Optometrist performs an examination, writes a spectacle prescription• While playing softball, one of the lenses is struck by the ball and shatters• Permanent loss of vision in the eye results
  9. 9. Notice how skillful questioningcauses the doctor to actually testifythat he breached the standard of careby failing to take an adequate historyand by not prescribing protectiveeyewear for secondary sports use.
  10. 10. CLAP Traps• Patient histories should always include avocational use of eyewear!• Make sure polycarbonate plastic (or Trivex) is specified on prescriptions when protection is a key clinical consideration• For ametropic patients playing contact sports, eyeguards meeting ASTM F803 standards or contact lenses should be prescribed
  11. 11. The third error is failure to inspect andverify ophthalmic lenses and framesprior to dispensing (especially “safety”frames).There are lens thickness requirementsfor “safety” lenses that must be verifiedby the dispenser. Failure to perform theinspection is negligence; the non-conforming lens is a “defective” product.
  12. 12. An 18-year-old man ordered safetyglasses from his optometrist. Later thepatient was in an automobile accident and suffered the loss of an eye when one ofthe lenses shattered. It was thendiscovered that when the original orderwas turned over to the optometriststechnician, she failed to mark the order asone for safety glasses. Thus, although thepatient had ordered and paid for safetylenses, he had received dress lenses. Thepatient sued, alleging negligence, and thecase was eventually settled in his favor.
  13. 13. Liability claims have also been broughtalleging injuries from dress frames,industrial (safety) frames, and sportsframes.Dress frames are most frequently acause of claims when they contribute toinjury, such as dislodgement of a lensthat strikes the eye; the failure of theframe to retain the lens is a contributingfactor to injury in such a case.
  14. 14. Both a safety frame and safety lensesmust be dispensed to patientsrequesting industrial (safety) glasses.Failure to provide an approvedframeeven if safety lenses areprescribedcan create liability.
  15. 15. Liability may ensue from failure to prescribe theappropriate frames for sports and recreationalactivities, if the risk of eye injury is significant.Frames for athletes should offer reasonableprotection for the sport. For participants of theracquet sports, polycarbonate frames with nohinges (and polycarbonate lenses) that meet theperformance standards for impact-resistanceestablished by the American Society for Testingand Materials (ASTM standard F803), must beprescribed. Although this standard was originallydevised for racquet sports,it is now recognized as the applicabledesign for “hard ball” sports as well.
  16. 16. Although ASTM F803 was originally devisedfor racquet sports, it is now recognized asthe applicable design for “hard ball” sportsas well.Ametropic patients who play baseball,basketball, football, soccer, and similarsports should be prescribed F803 frames.
  17. 17. The dispenser of eyewear is under alegal duty to be sure that ophthalmiclenses and frames meet standards forimpact resistance. These standards arethe same in all jurisdictions, and involve:• dress lenses• non-prescription (plano) eyewear• industrial (safety) eyewearThere is no similar standardfor sports eyewear.
  18. 18. Standards for dress (Z80.1-1999) andnon-prescription (Z80.3-1996) eyewearhave been adopted by the US Food andDrug Administration and state that:• All lenses shall be capable of withstanding the drop ball test (a 5/8 inch diameter steel ball weighing not less than .56 ounces must be dropped from 50 inches onto the lens).• Exceptions: plastic lenses, laminated lenses, and raised-edge multifocals can be certified by the manufacturer, who must test statistically significant samples.
  19. 19. Standards for industrial (safety)eyewear (Z87.1-2003) have beenadopted by the Occupational Safetyand Health Administration and state:– Basic impact prescription frames must contain the Z87 (or Z87-2) logo.– Basic impact prescription lenses must be no less than 3 mm in thickness, regardless of lens material, and pass a drop ball test (1 inch diameter steel ball weighing 2.4 ounces is dropped from 50 inches onto the lens).– High impact prescription frames must contain a Z87+ logo.– High impact prescription lenses must be no less than 2 mm in thickness, regardless of lens material, and pass a velocity impact test (1/4 inch diameter steel ball is fired at 150 ft/sec at the lens).– The trademark of the entity fabricating the lens must be etched on the edge of the lens.
  20. 20. Product liability claims involvingophthalmic lenses and frames may includeoptometrists (as the seller), but mostfrequently allege defective design ormanufacture. Thus, optometrists are notusually the primary defendant.Product liability law requires thatindividuals be warned if products aredangerous, and that products be inspectedbefore they are sold. Optometrists may beliable in such products-related claims.
  21. 21. A high school baseball player was practicing for avarsity game when he misjudged a fly ball that tippedoff his glove and struck his flipped-down planobaseball sunglasses. The lens shattered into sharpsplinters that pierced his eye, necessitating the eyesremoval nine days later. The sunglasses wereadvertised as "just perfect for active and spectatorsports—worlds finest sunglasses." They resembledordinary sunglasses except for the flip feature. But theircenter thickness was only 1.5 mm, and they were nottempered for impact resistance. The youngster suedthe manufacturer of the sunglasses under productliability law. The court held that the reduced centerthickness made the lenses unreasonably dangerousand awarded the plaintiff significant damages.
  22. 22. Guarantees can be established by thewords of assistants or employees of thedoctor as well as by the doctor himself.Careful instruction and supervision ofoffice personnel is necessary to avoid ill-chosen remarks about the impactresistance of ophthalmic lenses: theword “shatterproof” should never bespoken or written.
  23. 23. Warranties are promises that someproposition or fact is true. There are twobasic kinds of warranties:• express warranties are those that are explicitly stated (“these lenses are made of polycarbonate plastic”)• implied warranties are those that are derived by implication or inference from the nature of a transaction or the circumstances of the parties (optometrist prescribes glasses that are to be worn while playing sports, thereby warranting that they are suitable for that purpose)
  24. 24. A physically active young man sought the services ofan optometrist, who performed an examination andprescribed standard, heat-treated dress glass lenses.While on a hunting trip the young man tripped and fell,and his head struck the ground. One of the prescriptionlenses shattered as a result of the impact and severelylacerated his eye. Although he sought treatmentimmediately, he suffered a series of complications andultimately lost the use of the eye. He sued theoptometrist who had performed the examination andthe optical laboratory that had fabricated and heat-treated the lenses, alleging that the lenses were anunsafe product and that the optometrist had told himthat the lenses were shatterproof. The jury found thatthe optometrists remarks constituted a guarantee andawarded the young man substantial damages.
  25. 25. It is wise to have a form that explains lens and frameoptions to patients and that can be retained in the record for purposes of documentation. Important Information About Your Glasses Before you select the frames and lenses for your glasses, there are several things we need to consider. It is important that you describe to us the kinds of activities that you plan to undertake while wearing your glasses. If you will be wearing glasses at work, we need to know if there is a risk of injury to you from flying objects that could strike a lens and break it. If your job requires the use of safety glasses, you must tell us because special frames and lenses must be ordered. If you plan to wear your glasses while playing sports, please let us know so that we can help you select frames and lenses that will not create a risk of injury. In fact, if you participate in any activities that could potentially cause eye injury, you need to describe these activities to us so that we can advise you. Although no glasses are unbreakable, there are important differences between lenses and frames that make some glasses more protective when compared to others. We are here to help you choose the glasses that best satisfy your needs. Lenses A very important part of selecting your glasses is the choice of lens material. There are several different materials to choose from, and each has advantages and disadvantages, which are described below. Glass—reasonably resistant to scratching and, as a photochromic lens, has good ability to darken in sunlight; in high prescriptions glass can be heavy; glass lenses may not withstand impact well. Plastic—scratches more easily than glass, but lighter, especially in high prescriptions; can change darker in sunlight, and makes excellent sunwear; impact resistance is similar to glass. High index plastic—used for high prescriptions because lenses are thinner and much lighter than other materials; withstands impact a little better than regular plastic; good for sunglasses. Polycarbonate plastic—a high index material that is very impact resistant, which makes it the best choice for ocular protection; scratches more readily than glass but like other plastic materials is light and thus appropriate for high prescriptions; makes good non-prescription sunglasses too.
  26. 26. FramesAnother important consideration is the frame you select for your glasses. It should fit properly, be comfortable, andcompliment your appearance. It should also be safe. There are three basic categories of frames from which to choose.Dress—these are the frames worn for everyday activities that do not pose a risk of injury; the great majority of framesserve this purpose, being suitable for wear at home, at work, and during play.Safety—some frames have been specially designed to provide protection in the workplace; they can be identified by a“Z-87” logo on the frame; lenses for these frames must be of a certain thickness and have a special design in order forthem to meet the requirements for “safety glasses”.Sports—eyewear for high risk activities such as racquetball, squash, baseball, basketball, and football must meet specialdesign standards and be made of polycarbonate plastic; frames must meet the standards of “ASTM F-803” to provideoptimum protection. Making Your ChoicePlease consider carefully your needs for both frames and lenses. Based on these needs, we will be pleased to advise andassist you in the selection of the eyewear most suitable for you, which will be marked below.LENS MATERIAL [] Glass [] Plastic [] High Index [] PolycarbonateFRAMES [] Dress [] Safety [] SportsSPECIAL ORDERS [] Anti-scratch [] Anti-reflective [] Photochromic [] Sunglasses______________________________________________________ _____________________________________Verified By Date