Abstract
Purpose :
Bilateral structural and functional deteriorations are common in primary open-angle glaucoma. The aim of this study was to assess the ability of predicting the presence or absence of glaucoma progression in one eye given the state of progression in the fellow eye.
Methods :
The study included both eyes of 130 patients (with either ocular hypertension or primary open-angle glaucoma) enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study. All patients had at least 9 visits with retinal nerve fiber layer thickness (RNFLT; Spectralis OCT) and mean deviation (MD; 24-2 static automated perimetry, HFA II) measured over an average of 5.5 ± 1.1 years. Eyes showing a significant negative rate of change in global RNFLT or MD (significance set at 0.05) using simple linear regression, were classified as progressing. The proportion of patients progressing bilaterally and unilaterally from the 5th to 9th visit was determined for each index. Shannon’s mutual information was then used to quantify the reduction of uncertainty about whether an eye progresses or remains stable given knowledge about progression in the fellow eye. The reduction of uncertainty about which specific progression outcome (no progression, progression by RNFLT, progression by MD, or progression by both indices) in an eye was also determined. The analyses were replicated for the infero-temporal (IT) and supero-temporal (ST) sectors.
Results :
On average, 8–20% and 3–4% of the patients had bilateral RNFLT progression and bilateral MD progression, respectively (see Figure 1). Mutual information ranged from <0.01 to 0.16 bits. That is, the uncertainty in predicting whether an eye progresses or not was reduced by less than 7% given that we know the status of the fellow eye. Similarly, the uncertainty of predicting if the eye progressed or not with only RNFLT or MD or with both was reduced by less than 11%.
Conclusions :
The findings suggest that the state of progression in one eye may not be a good indicator of the presence or absence of the glaucoma changes in the fellow eye.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.