Topographical changes found to occur faster in eyes that progress to POAG

This prospective study found that the rate of structural change, specifically rim area loss, is significantly faster in hypertensive eyes that go on to develop primary open-angle glaucoma (POAG) compared with those that do not.

The authors compared the rate of topographic change in 42 participants from the Confocal Scanning Laser Ophthalmoscopy Ancillary Study to the Ocular Hypertension Treatment Study who developed POAG to that of 389 participants who did not develop POAG. Follow-up was 11 years for participants who didn't develop POAG and 5.6 years for those who did. 

The overall rate of neuroretinal rim area loss as measured with confocal scanning laser ophthalmoscopy was approximately five times faster in eyes that developed POAG compared with eyes that did not, with approximately 22 percent of eyes in the fastest quartile of rim area loss demonstrating POAG. Worse baseline visual field pattern standard deviation, higher IOP during follow-up, and larger disc area were associated with a faster rate of rim area loss.

Eyes in which POAG did not develop showed a statistically significant but slow rate of neuroretinal rim loss. The authors write that there are several possible explanations for this. First, these changes may represent age-related loss of retinal ganglion cells. Second, it is likely that Heidelberg Retina Tomograph (HRT) is detecting topographic changes in some of the approximately 55 percent of eyes that were not classified as clinically significant or as having POAG but were classified as undergoing progressive change based on masked assessment of stereophotographs. Third, HRT may be identifying early changes in some eyes that were not yet detectable on stereophotographs. And finally, some of the structural changes detected may represent false-positive results.

They write that these results demonstrate that measuring the rate of structural change using confocal scanning laser ophthalmoscopy can provide important information for the clinical management of ocular hypertension. However, further investigation is needed to determine how best to apply rate-of-change information to individual ocular hypertensive patients.