History

• General symptoms:

  • Unilateral/bilateral
  • Onset/duration
  • Any pain, photophobia, redness, discharge
• Visual symptoms:

  • Visual loss - sudden/gradual/distortion
  • Field defect - unilateral/bilateral/central/peripheral
  • Flashes/floaters - tends to be problem with the retina or vitreous gel
  • Diplopia - Horizontal/vertical/binocular/monocular (2 images when only looking through one eye)
• Past ocular history:

  • Refractive error - glasses, contact lens history
• Specifically ask for family history of ocular disease e.g. glaucoma
• Past medical history:

  Ocular presentation of systemic disease e.g. diabetes, malignancy, hypertension
• Social history:

  • Ability to take out ADLs
  • Driving
  • Hobbies
  • Social circumstances
• If a child:

  • Obstetric history, pregnancy/birth details
  • Neonatal problems
  • Immunisation history
• Key symptoms:

  • Red eye - front of eye e.g. sclera
  • Painless loss of vision - back of eye - no sensory nerves in optic nerve or retina
  • Distortion of vision or black spot in central vision - macula
  • Flashes or floaters - vitreous humour or retina
• Refractive error can take 2 forms:

  • Emmetropic - no error
  • Ametropic - have refractive error - myotopia, hypermetropia and astigmatism
• Emmetropia:

  • No refractive error and light rays from infinity are brought to a focus on the retina
  • Does not need any corrective lenses
• Myopia (Short-sighted)

  • Light rays from infinity are brought to a focus in front of the retina
  • The eye is too long = axial myopia
  • The lens is too strong from nuclear sclerotic cataract = index myopia
  • Can be corrected with a diverging (minus) lens - move the focal point further back in the eye
• Hypermetropia (long-sighted)

  • Light rays from infinity are brought to a focus behind the retina
  • The eye is too short
  • The converging power of the cornea or lens is too weak
  • Corrected with converging (plus) lens - light rays brought into focus on the retina
• Astigmatism:

  • The cornea is not spherical - rugby ball shaped
  • Light rays being focused by varies amounts
  • Scattering of light
• Accommodation (not the accommodation reflex):

  • Physiological mechanism that allows close objects to be focused on the retina
  • Light rays from close up are still diverging when meeting the lens
  • Need to increase power of the lens - ciliary muscle contracts and the lens assumes a more globular (convex) shape - thicker and more powerful
  • In the non-accommodative state the circular ciliary muscle is relaxed - allowing the suspensory ligaments of the lens to remain taut
  • With age the lens gradually hardens and is unable to accommodate = presbyopia
  • Why people require reading glasses when older