Prevalence and Causes of Low Vision
The World-Wide Situation The prevalence of visual impairment (VI) is the percentage of the general population who have the condition at a given point in time. Usually, the prevalence of…
OPHTHALMOLOGY
What Is Low Vision?
Low vision, partial sight and visual impairment are synonyms for the same state: reduced vision, with both eyes open, even with the best optical correction. The definition does not include…
Vergence and refraction
Objectives After working through this chapter, you should be able to: Explain what vergence and refraction are Explain how sign convention works, and be able to determine whether a distance…
Kitchen thin film interference
Objectives After working through this chapter, you should be able to: Explain ‘thin film interference’ Explain why the interference pattern is colourful Produce a thin film demonstration of your own…
Answers to test your knowledge questions
Below are some representative answers to the ‘Test Your Knowledge’ questions that appear at the end of every chapter. They’re designed to help you focus your learning, so make sure…
Create a ‘cornea’
Objectives After working through this chapter, you should be able to: Explain how the human eye focuses distant light on the retina Explain the different contributions of refractive index and…
Create your own camera obscura
Objectives After working through this chapter, you should be able to: Explain how a pinhole produces an image Create your own camera obscura Introduction As we discussed very briefly in…
Imaging the eye and measuring refractive error
Objectives After working through this chapter, you should be able to: Explain why it is difficult to see the back of the eye and the anterior angle without the help…
Answers to practice questions
Below are some representative answers to the ‘practice questions’ that appear within any chapters where we need to learn to apply some maths. They’re designed to help you focus your…
Measure the speed of light
Objectives After working through this chapter, you should be able to: Explain how microwaves heat food using interference Explain how we can use chocolate to measure the speed of light…
