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• What is the main focus of the study material on ophthalmoscopy?

  Understanding factors affecting magnification, field of view, and requirements for a good ophthalmoscope
• What is the purpose of direct ophthalmoscopy?

  To assess ocular health and examine the intraocular media and fundus
• How is magnification defined in the context of ophthalmoscopy?

  It is how much bigger the object appears through the ophthalmoscope than with the naked eye
• Why is the assessment of the fundus a legal requirement in primary eyecare examinations?

  It is necessary to screen for internal eye diseases and systemic diseases
• What is the formula for calculating magnification in ophthalmoscopy?


  $M =$$\frac{\beta}{\alpha} =$$\frac{\text{Ang. size of object through ophthalmoscope}}{\text{Ang. size of object at least distance of distinct vision}}$
• What are the common internal eye diseases screened during an ophthalmoscopic examination?

  • Cataract
  • Glaucoma
  • Maculopathy
• What systemic diseases are screened during an ophthalmoscopic examination?

  • Diabetes
  • Hypertension
• Who is the author of the study material on vitreous body anatomy?

  Dr. Howard Collins
• What does the variable $\beta$ represent in the magnification formula?


  $\beta$ represents the angular size of the object through the ophthalmoscope
• Who is the author of the study material on retinal anatomy and physiology?

  Dr. Howard Collins
• What is the primary focus of the study material regarding the vitreous body?

  It introduces vitreous body anatomy, ageing, and some clinical signs.
• Who invented the ophthalmoscope and in what year?

  Hermann von Helmholtz in 1851
• What does the variable $\alpha$ represent in the magnification formula?


  $\alpha$ represents the angular size of the object at the least distance of distinct vision
• What are the main objectives of the study material on retinal anatomy and physiology?

  • Overview of retinal anatomy and physiology
  • Understanding layers of the retina
  • Function and distribution of photoreceptors
  • Blood supply to the retina
• What are the main components discussed in the anatomy of the vitreous body?

  • Functions
  • Structure
  • Cortex
  • Gel
  • Attachments
  • Cloquet’s canal
• What is the function of the illumination system in an ophthalmoscope?

  It uses a reflector to illuminate the retina
• What is the innermost layer of the eye that sends light-induced nerve impulses to the brain?

  Retina
• What is the least distance of distinct vision typically considered in optics?

  25 cm
• What percentage of the volume of the eyeball does the vitreous body occupy?

  ~80%
• How is $\beta$ calculated for an emmetropic eye?


  $\beta =$$\frac{PD}{(1/Fe)} =$$BT \times Fe$
• How does the viewing system of an ophthalmoscope work?

  It uses neutralizing lenses to allow the examiner to view the retina
• What is the thickness of the retina at the optic nerve?

  0.6 mm
• What is the refractive index of the vitreous body?

  About 1.33
• What is one of the clinical signs related to the retina mentioned in the study material?

  Blood vessel tortuosity
• What are the main components of a direct ophthalmoscope?

  • Light source
  • Mirror for reflection
  • Viewing hole
  • Diaphragms
  • Multi-element condensing system
  • Light bulb
• What are the two main components of the retina?

  Neural retina and retinal pigment epithelium
• What is the dioptric length of the eye for an emmetropic eye?

  +60D
• What mechanical support does the vitreous body provide?

  It prevents transmission of mechanical shock to the retina.
• What happens to the rays emanating from a point in the patient’s fundus if both the patient and observer are emmetropic?

  They will emerge as a parallel beam and focus on the observer’s retina
• What is the main cause of blood vessel tortuosity?

  Diabetes
• Where are the retinal pigment epithelium (RPE) cells located?

  On Bruch's membrane
• What are the main components of the vitreous cortex?


  • Dense layer surrounding vitreous gel
  • Contains collagen fibres and cells
  • Fibroblasts produce collagen
  • Hyalocytes produce hyaluronic acid and collagen
• What does the term "arteriovenous nipping" refer to?


  Compression of a vein by an artery at a crossing point
• What are the clinical features of a direct ophthalmoscope?

  • Aperture stops
  • Range of lenses
  • Red-free diagnostic filters
  • Fixation targets
  • Graticules
  • Slit beam
• What are the layers of the neural retina?

  1. Internal limiting membrane
  2. Nerve fibre layer
  3. Ganglion cell layer
  4. Inner plexiform layer
  5. Inner nuclear layer
  6. Outer plexiform layer
  7. Outer nuclear layer
  8. External limiting membrane
  9. Photoreceptors

  10. Retinal pigment epithelium
• What is the formula for magnification in a standard reduced eye?


  $M =$$\frac{BT \times Fe}{4}$
• What is the function of hyalocytes in the vitreous cortex?

  They produce hyaluronic acid and collagen.
• What is the role of chondroitin sulphate in the vitreous gel?


  It forms flexible connections between collagen fibres.
• What is the function of the retinal pigment epithelium (RPE)?

  To absorb scattered light and maintain the outer blood-retinal barrier
• What is the equation for magnification in an ametropic eye?


  $M =$$\frac{Fe'}{4(1 - wK)}$