Factors influencing underestimation of glaucoma likelihood

This prospective study found that errors in assessing vertical cup-to-disc ratio, cup shape, retinal nerve fiber layer (RNFL) defects and disc hemorrhage commonly led to the underestimation of glaucoma likelihood.

This study highlights the factors ophthalmologists should pay special attention to when assessing a patient for the possibility of glaucoma. Although we know these things influence glaucoma diagnosis and can also be predictive of progression in some cases, in a busy clinic we sometimes forget to assess all of these factors.  

The authors used data from the Glaucomatous optic neuropathy evaluation (GONE) project to investigate how the assessment of key morphologic features of the optic disc and RNFL influence the assessment of glaucoma likelihood in ophthalmology trainees and comprehensive ophthalmologists.

Ophthalmology trainees and comprehensive ophthalmologists underestimated glaucoma likelihood in approximately one in five discs and were twice as likely to underestimate rather than overestimate glaucoma likelihood.

Errors in the assessment of vertical cup-to-disc ratio, RNFL, rim loss and disc hemorrhage were most influential in the incorrect estimation of glaucoma likelihood. When all four parameters were incorrectly assessed, underestimation increased to almost half.   

They conclude that the results of this study will facilitate creation of targeted teaching tools for ophthalmology trainees and continuing medical education modules for comprehensive ophthalmologists.