Fundus Lens

• What are the two contrasting methods mentioned in the study material?

  Direct and MIO
• What are the characteristics of the images produced by different methods?

  • Direct: Virtual, Upright, No stereopsis, ~5° field of view, ~15x magnification
  • MIO: Real, Upright, Yes stereopsis, ~12° field of view, ~5x magnification
• What is the field of view for the Direct method?

  ~5° (1-2 DD)
• What is the field of view for the MIO method?

  ~12° (4 DD)
• What is the limitation of the Direct method?

  Equator
• What is the limitation of the MIO method?

  Beyond equator
• What are the contraindications and indications for a dilated fundus exam (DFE)?

  • Contraindications: Review OA guidelines, patient not being dilated, DFE contraindicated
  • Indications: Routine eye exam, systemic health issues, glaucoma, retinal detachment, visual disturbances, etc.
• What should always be examined as part of a routine eye exam?

  The posterior eye
• What should be attempted routinely on a patient not being dilated?

  Undilated fundus lens examination
• What should be performed when you dilate your patient?

  Both fundus lens and BIO
• What are the indications for a fundus lens exam?

  • Thorough ocular fundus exam
  • Reduced best corrected visual acuity
  • Reported visual disturbances (e.g., floaters, shadows)
  • Diagnosis of ocular conditions
  • Systemic health issues (e.g., diabetes, hypertension)
• What is the magnification of the 60 D lens?

  1. 15x
• What is the field of view for the 78 D lens?

  81 / 97°

  
• What is the primary application of the Super 66 lens?

  High magnification view of the posterior pole

  
• What is the setup process for a fundus lens examination?

  • Dim room lights
  • Align canthus markings
  • Instruct patient to keep head against rests
  • Adjust PD and ensure stereo
  • Start with low magnification and vary during examination

  
• What should be checked before inserting the fundus lens?

  Ensure the lens is clean
• How should the fundus lens be held during examination?

  Between index finger and thumb, perpendicular to corneal surface
• What are the steps to insert the fundus lens?

  1. Place lens in center of pupil
  2. Position top of lens at brow
  3. Stabilize hand holding lens
  4. Adjust slit lamp position for clarity
• What should be done if the view is lost during examination?

  Try small movements of the lens and recheck centration
• What is the purpose of using a red-free filter during examination?

  • Increase intensity
  • Differentiate pigment from blood
  • Visualize nerve fiber layer
• What should be documented during a fundus lens exam?

  • Type of drops used
  • Findings on ONH, RNFL, AV ratio, macula, mid-periphery, and periphery
  • Any abnormalities noted
• What is the C/D ratio in fundus lens documentation?

  The cup-to-disc ratio
• What does the term "AV ratio" refer to in fundus lens documentation?

  The artery-to-vein ratio
• What is the purpose of examining the macula during a fundus lens exam?

  To check for flat/raised areas, reflex presence, drusen, and pigment changes
• What should be noted about the mid-periphery and periphery during the exam?

  Clear/lesions/hemorrhages should be documented