Emily Yeung

Publications (2)10.25 Total impact

• Article: Higher magnification lenses versus conventional lenses for evaluation of diabetic neuropathy by corneal in vivo confocal microscopy.

  Drew A Hume, Leif Erik Lovblom, Ausma Ahmed, Emily Yeung, Andrej Orszag, Tae Maen Shin, Vera Bril, Bruce A Perkins
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  ABSTRACT: We tested agreement for small fibre morphology using corneal in vivo confocal microscopy between the recently available higher-magnification 300 μm(2) and the conventional 400 μm(2) field-of-view lenses. We found insignificant bias for corneal nerve fibre length indicating that either lens could reasonably be applied to research and clinical screening for diabetic neuropathy.
  Diabetes research and clinical practice 05/2012; 97(2):e37-40. · 2.16 Impact Factor
• Article: Detection of diabetic sensorimotor polyneuropathy by corneal confocal microscopy in type 1 diabetes: a concurrent validity study.

  Ausma Ahmed, Vera Bril, Andrej Orszag, Jenna Paulson, Emily Yeung, Mylan Ngo, Steven Orlov, Bruce A Perkins
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  ABSTRACT: We aimed to determine the corneal confocal microscopy (CCM) parameter that best identifies diabetic sensorimotor polyneuropathy (DSP) in type 1 diabetes and to describe its performance characteristics. Concurrent with clinical and electrophysiological examination for classification of DSP, CCM was performed on 89 type 1 diabetic and 64 healthy subjects to determine corneal nerve fiber length (CNFL), density, tortuosity, and branch density. Area under the curve (AUC) and optimal thresholds for DSP identification in those with diabetes were determined by receiver operating characteristic (ROC) curve analysis. DSP was present in 33 (37%) subjects. With the exception of tortuosity, CCM parameters were significantly lower in DSP case subjects. In ROC curve analysis, AUC was greatest for CNFL (0.88) compared with fiber density (0.84, P = 0.0001), branch density (0.73, P < 0.0001), and tortuosity (0.55, P < 0.0001). The threshold value that optimized sensitivity and specificity for ruling in DSP was a CNFL of ≤14.0 mm/mm(2) (sensitivity 85%, specificity 84%), associated with positive and negative likelihood ratios of 5.3 and 0.18. An alternate approach that used separate threshold values maximized sensitivity (threshold value ≥15.8 mm/mm(2), sensitivity 91%, negative likelihood ratio 0.16) and specificity (≤11.5 mm/mm(2), specificity 93%, positive likelihood ratio 8.5). Among CCM parameters, CNFL best discriminated DSP cases from control subjects. A single threshold offers clinically acceptable operating characteristics, although a strategy that uses separate thresholds to respectively rule in and rule out DSP has excellent performance while minimizing unclassified subjects. We hypothesize that values between these thresholds indicate incipient nerve injury that represents those individuals at future neuropathy risk.
  Diabetes care 02/2012; 35(4):821-8. · 8.09 Impact Factor