When it comes to anterior eye grading for issues such as limbal, bulbar and palpebral redness, clinicians may obtain the best results if they use 0.5 grading increments, a team of researchers from Ireland and the UK suggest.

Their study, published in Contact Lens Anterior Eye, included 61 eye care practitioners and 127 second-year optometry students who graded the bulbar, limbal and palpebral hyperemia of the upper lid of four patients imaged with a digital slit lamp. The patients presented randomly three times in a sequence, while the graders used an Efron printed grading scale to the nearest 0.1 and 0.5 increment and integer grade, in a randomized order. Graders were masked to their previous responses.

For most grading conditions, fewer than 20% of clinicians showed a difference of 0.1 or less in grade from the mean. In contrast, more than 50% of the student graders and 40% of experienced graders showed a difference in grade from the mean within 0.5 for all conditions.

The study found the students’ grading precision was better in both the 0.1 and 0.5 increments compared with the nearest unit. For limbal hyperemia, student grading was more accurate with the 0.5 measurement.

In the experienced practitioner group, limbal grading precision was not affected by grading step increments. However, 0.1 and 0.5 increments were better than 1.0 for bulbar hyperemia. Additionally, the narrower 0.1 grading increment was better than 0.5, while both were superior to the 1.0 increment for palpebral hyperemia.

Although narrower interval scales maximized the ability to detect smaller clinical changes, the grading increment should not exceed one standard deviation of the discrepancy between measurements, the researchers noted.