Abstract
Purpose :
We sought to assess, correlate and compare structural and functional indices between glaucomatous patients with high (HTDH) and low-tension (LTDH) optic disc hemorrhages.
Methods :
In this prospective study, we enrolled glaucomatous patients with DH from two Glaucoma Services.Patients were classified as HTDH if presenting with an intraocular pressure (IOP)≥16 mmHg at the time of DH detection. Those with an IOP<16 mmHg were classified as LTDH (median split). Clinical and ocular data from the time of DH detection were collected. Functional (Mean Deviation index [MD] from standard automated perimetry) and structural indices (average retinal nerve fiber layer [RNFL] thickness from spectral domain optical coherence tomography) were compared between groups. Anova was used to compare data with normal distribution between groups, while the Kruskal-Wallis was used for those non-normally distributed. Regression analysis was used to investigate structure-function correlations in each group. Statistical significance was set at p<0.05.
Results :
Fifty-one patients were included (LTDH=29 eyes; HTDH=22 eyes). Mean age was similar between patients with LTDH (62.7 years) and HTDH (60.2 years; p=0.36). Median IOP (range) in eyes with LTDH and HTDH was 14 mmHg (8 – 15) and 18.3 mmHg (16 – 42), respectively. There were no significant differences between eyes with LTDH and HTDH regarding median MD values (-3.2 dB vs -2.9 dB; p=0.87) nor average RNFL thickness (81μm vs 81.3μm; p=0.95). Although we found a significant correlation between RNFL and MD values in eyes with HTDH (R2=0.16; p=0.04), no significant correlation was found in LTDH eyes (p=0.32).
Conclusions :
Glaucomatous eyes developing DHs with treated IOPs in the low teens present similar amounts of visual field and RNFL losses compared to those with higher IOPs. One can infer that the IOP level necessary to induce a DH in these patients does not seem to be related to the disease stage as assessed by these structural and functional indices. Moreover, the fact that no significant structure-function correlation was found in eyes with LTDH suggests a greater mismatch between anatomic loss and visual field involvement in these eyes. Whether this finding is related to a possible difference in the underlying mechanism of ganglion cell loss in these LTDH eyes deserves further investigation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.