Comparison of two ophthalmoscopes for direct ophthalmoscopy

Clin Exp Ophthalmol. 2011 Jan;39(1):30-6. doi: 10.1111/j.1442-9071.2010.02403.x. Epub 2010 Oct 19.


Background: To measure the ease of use and performance of the Optyse lens-free ophthalmoscope compared with the standard Keeler pocket ophthalmoscope, and to assess its suitability as an inexpensive ophthalmoscope for medical students.

Design: Randomized cross-over study.

Participants: Twenty second-year medical students, 10 as ophthalmoscopists ('observers') and 10 as 'patients'.

Methods: Students used both ophthalmoscopes to examine the optic disc in each eye of 10 'patients'. They were randomized as to the order in which they were used. A Consultant ophthalmologist was used as the gold standard.

Main outcome measures: Main outcome measures were accuracy in estimating vertical cup:disc ratio (VCDR), ease of use (EOU) for each examination, and overall ease of use (OEOU).

Results: Of 400 attempted eye examinations, sufficient visualization was achieved in 220 cases to allow a VCDR estimation: 107/200 VCDR estimates with the Optyse and 113/200 with the Keeler. Accuracy of VCDR estimates was better with the Optyse by the equivalent of 0.05 VCDR (P = 0.002). There was no significant difference in EOU or OEOU between the two ophthalmoscopes. EOU for 400 examinations: median (IQR) of 6 (3-8) for Optyse versus 6 (3-8) for Keeler (P = 0.648). OEOU for 20 scores: median (IQR) of 6.5 (2-9) for Optyse versus 5.5 (3-8) for Keeler (P = 0.21).

Conclusion: Medical students found the Optyse and Keeler pocket ophthalmoscopes to be of similar ease of use and performed slightly better with the Optyse when estimating VCDR. The lens-free Optyse ophthalmoscope is a reasonable alternative to the standard Keeler pocket ophthalmoscope.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Cross-Over Studies
  • Education, Medical, Undergraduate / methods
  • Equipment Design
  • Humans
  • Ophthalmology / education*
  • Ophthalmoscopes*
  • Ophthalmoscopy / methods*
  • Optic Disk / anatomy & histology*
  • Reproducibility of Results
  • Students, Medical
  • Teaching / methods*