1 LASIK - IntroductionIntroduction - Activity 1 - Activity 2Activity 1Activity 2 - Activity 3 - Activity 4Activity 3Activity 4 - Activity 5Activity 5 Click the links below to access the activities:

2 Raise your hands! Are you wearing glasses? Are you wearing contact lenses? Do you have any friend or relative who has had the LASIK( 激光矯視 ) operation? Estimate how many people of your age have short-sightedness in Hong Kong?

3 Do you have short-sightedness? It is estimated that over 59% of secondary school students in Hong Kong have short-sightedness! Ocurrence of Short-sightedness Age GroupOcurrence (Source: HK Government Press, 2000)

4 Activity 1 Revision about the structure of the eyes

5 LASIK – What is it? Activity 2

6 What is LASIK? LASIK stands for Laser Assisted In Situ Keratomileusis - it means the use of a laser to correct short- / long-sightedness. How does it work?

7 Let’s do “eye surgery” in the laboratory! Simulation partReal part of eye simulated Illuminated letter “F”Object in front of eye Movable stand with a screen Retina Gelatin ShellCornea Hot tools with appropriate shapes to reshape the cornea, e.g. spatula, metal wire made Laser

8 Simulation 1: Correcting short-sightedness The image is formed in front of the retina. How can we shift the image onto the retina?

9 Simulation 2: Correcting long-sightedness The image is formed behind the retina. How can we shift the image to the retina?

10 How is LASIK really performed?

11 How is LASIK performed? Step 1: The Microkeratome (a surgical blade) cuts a thin flap of corneal tissue Microkeratome

12 How is LASIK performed? Step 2: The flap is lifted and the laser removes some tissue on the surface of the cornea so that the cornea is reshaped. Flap Laser Cornea is reshaped

13 How is LASIK performed? Step 3: The flap is replaced in its original position. The operation is finished. Hinged flap is folded back

14 Video Time Let’s watch a video demonstration of LASIK

15 Activity 3 How has the technology of refractive surgery been developed?

16 What is Science? What is Technology? Which one (Science or Technology) come first?

17 Science is …. Comes from the Latin word scientia which means “knowledge” Human attempt to ‘know’ (understand) the natural world Often through observation, identification, description, experimental investigation, and theoretical explanations... Provide explanations for natural phenomena based on empirical ( 以觀察或實驗為依據的 ) evidence

18 Technology …. Comes from the Greek word techne, meaning artifice ( 人工製品 ) or art ( 技巧 ) or craft ( 工藝 ) Can be physical objects e.g. as complicated as rocket, iPod nano or as simple as knife or can opener Can be a technique/skill e.g. the technology of building nuclear bomb or pyramids Often driven by societal demand - to extend human abilities, to satisfy human needs and wants

19 Science or Technology come first? Both can! Science technology e.g. Atomic physics leads to nuclear bomb and nuclear power (poor and good application of science by human) Technology Science Ancient people put sandbag on their eyes to correct shortsightedness without knowing the structure of the eyes and the theory of optics.

20 Technology Science Society Explain the relationship between science, technology and society based on the above drawing.

21 Is LASIK for everyone? Activity 4

22 Is LASIK for everyone? To be a good candidate for LASIK surgery, you should : Have a stable eye condition for the past few years Be free of corneal disease or a thin cornea Understand fully the benefits & side effects of LASIK Have realistic expectations of the outcomes Not be pregnant Be over 18 years old

23 Is it safe?

24 Risks and Side Effects of LASIK Side effects associated with LASIK include: Haloes and circles around lights at night Dry eyes Eye discomfort Under or over-correction

25 Activity 5 Be a wise consumer and critical about the contents in advertisements!