Rod Intercept Time Longer in Patients with Early/Intermediate AMD

Senile Macular Degeneration
Retinal Fluorescein Angiogram Of Age Related Macular Degeneration. (Photo By BSIP/UIG Via Getty Images)
The study found a significant correlation between rod intercept time and saccade duration in the AMD group.

This article is part of Optometry Advisor’s conference coverage from the 2021 meeting of the American Academy of Optometry, held in Boston from November 3 to 6, 2021. The team at Optometry Advisor will be reporting on a variety of the research presented by the primary eye care experts at the AAO. Check back for more from the AAO Optometry 2021 Meeting..

In patients with early to intermediate age-related macular degeneration (AMD), rod intercept time is longer than in individuals without early to intermediate AMD, according to findings presented at the American Academy of Optometry (AAO) 2021 annual meeting, held in Boston from November 3-6.

Researchers conducted a study to determine if any changes could be noted in saccades to the parafovea in early/intermediate patients with AMD. The study included 14 participants with early/intermediate AMD and 14 healthy patients as age-matched controls who first received a complete eye exam to determine visual acuity (VA) and fields using optical coherence tomography (OCT) and fundus photos, and which revealed no significant difference in VA between groups (P =.425). Participants’ dark adaptation for 30 minutes was then measured using the AdaptDx® (MacuLogix) and a saccade eye movement was measured using a Tobii TX300® (Tobii Pro) eye tracker. Dark adaptation and saccade targets, both 2 degrees in size, were in the same retinal location (5 degrees superior retina). This configuration has been shown in patients with AMD to display a loss in photoreceptor sensitivity. 

The study found that, during dark adaptation, participants with early/intermediate AMD had a statistically significant, longer rod-intercept time (P =.007), but no other parameters showed a difference that was statistically significant between the AMD and control groups. For all participants combined (P =.004) and the AMD group alone (P =.028), a significant correlation was found between rod-intercept time and saccade duration, but not for the control group alone (P =.486). 

The researchers note that, even though dark adaptation time was increased at 5 degrees in the superior retina, saccade eye movement parameters to that location are not altered. However, the significant correlation between rod intercept time and saccade duration in the AMD group suggests that neural processing is altered in that location.

Visit Optometry Advisor’s conference section for complete coverage of AAO 2021.



Habib M, Ridder W. Dark adaptation and saccade eye movements in early/intermediate age-related macular degeneration (AMD). Poster presented at: The American Academy of Optometry 2021 annual meeting; November 12-15; Boston. Board #99