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Detection of ocular disease by a vision-centre technician and the role of frequency-doubling technology perimetry in this setting
  1. Ravi Thomas1,2,3,
  2. Shoba Naveen4,
  3. Praveen K Nirmalan2,
  4. Rajul Parikh2
  1. 1Queensland Eye Institute, Brisbane, Australia
  2. 2LV Prasad Eye Institute, Hyderabad, Andhra Pradesh, India
  3. 3University of Queensland, Brisbane, Queensland, Australia
  4. 4Siloam Eye Hospital, L.V. Prasad Eye Institute, Madanapallee, Andhra Pradesh, India
  1. Correspondence to Dr Ravi Thomas, Queensland Eye Institute, South Brisbane, Queensland 4101, Australia; ravi.thomas{at}


Aim To document the detection of significant ocular pathology by a vision-centre technician in an emerging economy World Health Organization recommended eye care delivery setting, and determine whether a frequency-doubling perimeter (FDT) improves that performance.

Material and methods Consecutive patients above the age of 12 years attending a vision centre were included. A vision technician (VT) determined visual acuity and performed a slit-lamp examination, applanation tonometry and undilated fundus examination followed by a 20-1 FDT screening test. VT and FDT findings were compared with the gold standard of masked comprehensive examination by an ophthalmologist. Sensitivity, specificity and predictive values were calculated.

Results 1764 of 1829 patients fulfilling the inclusion and exclusion criteria were analysed. The VT had a sensitivity and specificity of 68% (95% CI 63.1% to 72.7%) and 90% (95% CI 88.35% to 91.5%) for detection of significant ocular disease; corresponding values for FDT alone were 87.8% (95% CI 84% to 90.8%) and 79% (95% CI 76.8% to 81%). 71 of the 115 patients having significant ocular pathology missed by the VT were detected by FDT. A positive finding by the VT and/or positive FDT had a positive predictive value of 47%.

Conclusions An examination by a VT within the accepted World Health Organization model may usefully leverage limited ophthalmological capacity in emerging economies. Adjunctive FDT testing may further improve VT referral efficiency.

  • Ocular pathology
  • vision centre
  • vision technician
  • frequency doubling technology perimetry
  • positive predictive value
  • intraocular pressure
  • vision
  • public health
  • electrophysiology
  • diagnostic tests/investigation

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  • Competing interests None.

  • Funding RT is funded by Prevent Blindness Foundation through Viertels Vision.

  • Ethics approval Ethics approval was provided by the ethics committee of the LV Prasad Eye Institute.

  • Provenance and peer review Not commissioned; externally peer reviewed.