tasmanian eye clinics g.p. seminar

1. Tasmanian Eye Clinics G.P. Seminar

6. Central vs Peripheral Vision Macula function. Detailed with high definition. Reading and colour vision. Reliance on cones. Parvocellular pathway. Discerns movement and action. Relies on rods. Dark adaptation function. Magnocellular pathway

9. VISUAL ACUITY RECORD RECORD RECORD You are not defendable if there is no recorded acuity.

10. Recording Record the result in the following manner. Remember no record = no defence

11. Visual Acuity Va’s Recorded at 6metres or 3metres. The Numerator represents the distance used and the denominator the line read. Ie 6/6 represents reading the line at 6 metres that should be read at 6 metres. The Americans use 20/20 ( ie 6 metres ) as the convention. Young people can read better than 6/6 ,usually 6/5 or 6/4. The chart used is actually based on a fallacy but become imbedded in law

16. Recording Visual Acuity. V.r (V.r (uncorrected) at distance. corrected ie with glasses) No glasses with Pin Hole. V.r. for near. V.l.( uncorrected) at distance. V.l.(corrected ie with glasses). No glasses with Pin Hole. V.l. for near.

17. PIN HOLE A pinhole or stenopaeic device converts the eye into a pinhole camera and neutralises refractive error. A pinhole is used to create a shorthand refraction. If Visual Acuity is depressed it may be due to a simple refractive error . The pinhole test allows a non optical person to assess the visual potential of the eye.

18. DEVICE PIN HOLE

19. Near Vision Recorded in point print form.(remember the readers!) N8 is approximately the size of newsprint. N6 the phone book. N10 most magazines. Record with reading glasses if used.

20. Clues from the Visual Acuity Reading one side of chart may indicate a hemianopia. “Searching” movements of the head when trying to read the letters may suggest macula changes. A poorer reading acuity compared to the distance acuity suggests macula dysfunction.

21. Technique Points Cover each eye for the patient carefully to avoid “peeping”. Record the best line the patient can see even if there are mistakes and record as eg 6/6-2 Single letter vision charts are easier to read than multiple letters but mask “ crowding”. Beware the illiterate and the memorised chart.

23. ACUITY STANDARDS 6/12 (corrected or uncorrected ) in at least one eye is the driving standard for an ordinary licence. A visual field of 120 degrees (binocular ) is also required. 6/9 for public vehicle licences. <6/60 for the blind pension or <5degrees of field in the better eye.

24. A little about optics and lenses

25. Optics The power of an optical surface is at the interface between a less dense and more dense medium . This creates REFRACTION. All optical devices depend on refraction. The following illustrate the main types of lenses.

28. Lenses. Convex. Image moves in opposite direction. Magnify. Focal plane concept Identify. - lenses. Concave. Image moves in same direction. Make object smaller. Focal plane concept. Identify.

29. Spectacles. Single vision. Bifocals etc. Multifocals. High + and – and the problems. Identify main types.

31. Spectacle Materials CR39 1.49 High Index Plastics(1.67)

32. Practical Training (20 mins) Visual Acuity Drills. Pin Hole use. Methods of recording. Identification of basic optical lenses. Identification of basic glasses types. Chart types & advice re use.