EYE-REVISE

• The role of the eye is to focus light on the retina in order to form an image of the surrounding world, and transduction is performed to generate an electrical signal from the image which is sent to the brain. 

• This depends on several key properties of the eye: 

  • transparency of ocular media​

  • refraction of light by ocular media

  • shape and size of the eye

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• Some key terms: 

  • emmetropia ​= absence of refractive error; light rays from infinity are brought to a focus on the retina

  • ametropia = presence of refractive error - hypermetropia, myopia or astigmatism

  • hypermetropia = light rays brought to a focus behind the retina

    • caused by short eye or weak converging power of lens​

  • myopia = light rays brought to a focus in front of the retina

    • eye is too long or converging power of the lens is too strong​

  • astigmatism = cornea is rugby ball shaped rather than spherical

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• The guide to ophthalmology for undergraduates presented here will explore the basic anatomy of the eye, important diseases, and key ophthalmic presentations and their associated differentials. 

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