Visual field (VF) defects caused by thyroid eye disease (TED)-compressive optic neuropathy are usually inferior and show a predictable pattern of progression, a study in the American Journal of Ophthalmology reports.

The study reviewed records from a single institution to identify patients with progressive VF defects secondary to TED-compressive optic neuropathy. Two independent reviewers analyzed the VF defects and classified them into one of 10 categories, which were then divided into three stages based on the pattern of progression. A miscellaneous category (stage X) was also included.

Stage 1 VF defects were the earliest detectable and involved the inferior VF with three levels of severity. Stage 2 VF defects were defined as having two distinguishable levels of severity and occurred as the inferior defects advanced above the horizontal midline to involve the superior VF. The stage 3 category encompassed progression of stage two VF defects up to complete loss of inferior and superior hemifields.

Of the 234 VFs performed on 37 eyes of 23 subjects, the researchers found inferior defects were most common:

• Stage 1a (small inferior paracentral defect):9.4%
• Stage 1b (large inferior paracentral defect): 47.9%
• Stage 1c (inferior altitudinal defect): 4.7%

Stage 2a (inferior altitudinal with superior advancement above the horizontal meridian) occurred in 17.5% of VFs, stage 2b (inferior altitudinal with superior arcuate) were found in 2.6%, and stage 3 (total loss) occurred in 2.1%.

The researchers noted longitudinal sequences of VF defects in 83.8% and showed a predictable progression pattern from least to more severe. The researchers observed a reverse order of VF defect progression in 15 eyes that showed improvement in their condition.

The VF defects in these patients can be effectively categorized in this novel classification system, the researchers wrote in their paper.