Findings from a recent study published in JAMA Ophthalmology evaluated whether the proximal location of optic disc hemorrhage (ODH) could predict glaucoma progression.
Give me some background.
Although ODH is widely recognized as a substantial risk factor for the development and progression of glaucoma, it remains unclear whether the location of ODH in glaucoma patients impacts the risk of disease progression.
Note: To clarify the pathophysiology of ODH in glaucoma, a previous study categorized ODH into two subgroups (peripapillary- and cup-type) based on the location of its proximal component.
Now talk about the study.
In this longitudinal observational cohort study, investigators recruited participants from an ongoing open-angle glaucoma (OAG) cohort at Seoul National University Hospital in Seoul, Korea.
The research team included 146 eyes of 146 patients who had:
- A diagnosis of OAG based on the presence of glaucomatous optic neuropathy with compatible visual field (VF) loss and open anterior chamber angle
- One or more ODH
- At least 5 years of follow-up data
- At least 5 reliable VF examinations
And then?
They then organized the patient data into ODH subtypes based on their respective proximal locations, including:
- Cup-type group
- Laminar subtype (proximal location of ODH was the lamina cribrosa [LC])
- Marginal subtype (on cup margin)
- Peripapillary-type group
- Rim subtype (on disc rim)
- Parapapillary subtype (outside the papillary border)
Cohort characteristics?
These included:
- Mean follow-up period: 10.9 years (range 5.1-17.8 years)
- Mean age at which ODH was first detected: 55.1 years (range 21-77 years)
- Gender ratio in cohort: 94 participants (64.1%) were female
Over the mean follow-up period of 10.9 years, glaucoma progression was detected in 94 eyes (61.4%) with a mean deviation (MD) of -0.48 dB per year.
Findings?
The cup-type group showed a faster rate of MD loss relative to the peripapillary-type group (-0.56 vs -0.32 dB per year, difference = 26.0%, 95% confidence interval [CI] -0.37 to -0.11, P = 0.01).
Using a life table analysis, the cup-type group also showed a higher cumulative probability of progression of glaucoma (80.4%) relative to the peripapillary group (54.4%, difference = 26.0%, 95% CI 11.4-40.6%, P < 0.001).
Anything else?
The presence of cup hemorrhage was associated with an increased risk of glaucoma progression (hazard ratio 3.28, 95% CI 2.12-5.07, P < 0.001).
- In addition: Cup-type ODH was associated with MD loss rate in the regression analysis.
Expert opinion?
In a commentary also published in JAMA Ophthalmology, the authors explained that “the findings of this study are important as they support both vascular dysregulation and mechanical shearing of blood vessels at the level of the LC as key mechanisms in disc hemorrhage pathogenesis.”
Go on …
Overall, this study demonstrated that VF progression was faster in glaucomatous eyes with ODH located at a focal LC defect, the commentary authors noted.
And this suggests: That “deep in the cup, the disc hemorrhage would put a stranglehold on the retinal nerve fibers, thus putting them between a proverbial rock (the blood) and a hard place (the underlying laminar),” they stated.
Limitations?
These included:
- ODH location could change and the subtype might also alter as it absorbs depending on when it was identified
- ODH that occurred outside of the observation period could not be fully evaluated
- The study evaluated medical records from a single tertiary medical center, which may have introduced selection bias
- No analysis of focal LC defect was performed
Take home.
These findings suggest that glaucoma progression was higher in cases of cup-type ODH, supporting the potential utility of evaluating the proximal location of ODH to predict how glaucoma might progress.