Editors Selection IGR 16-2

Clinical Examination Methods: Detecting glaucoma

Remo Susanna Jr

Comment by Remo Susanna Jr on:

56995 Glaucomatous optic neuropathy evaluation project: factors associated with underestimation of glaucoma likelihood, O'Neill EC; Gurria LU; Pandav SS et al., JAMA ophthalmology, 2014; 132: 560-566

See also comment(s) by Steve Mansberger

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In this Internet-based study with multinational participation, a series of 42 monoscopic optic disc photographs of healthy and glaucomatous eyes were presented to clinicians using the GONE Project Program Ophthalmology. Participants were ophthalmic clinicians, glaucoma subspecialists, comprehensive ophthalmologists, and ophthalmology trainees from 22 countries who self-registered for the Glaucomatous Optic Neuropathy Evaluation.

Trainees and comprehensive ophthalmologists underestimated glaucoma likelihood in a mean (SD) of 22.1% (1.6%) and 23.8% (1.8%) of discs, respectively. Ophthalmology trainees and comprehensive ophthalmologists overestimated glaucoma likelihood in a mean (SD) of 13.0% (1.2%) and 8.9% (1.3%) of discs, respectively based on optic discs graded by glaucoma subspecialists. Underestimation of vertical cup-disc ratio and failure to identify retinal nerve fiber layer loss, disc hemorrhage, or rim loss were most likely to lead to underestimation of glaucoma.

Overestimation of glaucoma likelihood was associated with overestimation of retinal nerve fiber layer loss, rim loss, vertical cup-disc ratio, disc hemorrhage, and incorrect assessment of disc tilt and was more likely in large discs.

There are several limitations of this study, some of them pointed out by authors include the use of monoscopic disc images, and differences in the skill of the expert group (invited) and participants (self-selected) of different countries.

The ability to detect the disease may be influenced by time of experience, continuous medical education, conditions of work, and other factors. Because of that, the current findings of this study cannot be generalized to all general ophthalmologists. Also the participants are from different countries with different expertise on diagnosing glaucoma. Depending on the quality of the medical education in each country and the other parameters cited above, the results could be influenced in one-way or another. It would be nice if the authors have presented this information.

Also the interobserver agreement in glaucoma likelihood (?, 0.63; 95% CI, 0.60-0.67) for the glaucoma subspecialists reflects that there is still a substantial disagreement between them.

Despite of that, the results of this study are in agreement with two previous studies1,2 with different methodology and provides important targeted teaching tools for medical education modules, focusing on specific aspects of disc examination.


  1. Vessani RM, Moritz R Batis, L, et al. Comparison of Quantitative Imaging Devices and Subjective Optic Nerve Head Assessment by General Ophthalmologists to Differentiate Normal From Glaucomatous Eyes. Journal of Glaucoma. 2005;18:253-261.
  2. Reus NJ, Lemij HG, Garway-Heath DF, et al. Clinical Assessment of Stereoscopic Optic Disc Photographs for Glaucoma: The European Optic Disc Assessment Trial. Ophthalmology.

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