Retinal vein occlusion (RVO) is usually associated with conditions like hypertension, diabetes, hyperlipidemia, and systemic vascular disease.
But researchers have increasingly begun examining whether hematologic malignancies may also contribute to retinal vascular compromise in certain patients.
As such: A recent systematic review and meta-analysis published in Retina evaluated ocular manifestations and retinal vascular complications in leukemia patients across more than 1,000 participants.
Why are researchers even looking at leukemia in retinal vein occlusion?
Part of the interest comes from how leukemia affects circulation and blood composition overall, particularly as it’s already known to contribute to:
- Hyperviscosity
- Leukostasis
- Coagulopathy
- Impaired microvascular circulation
Researchers have increasingly questioned whether those same abnormalities may impair retinal circulation enough to contribute to retinal vascular events, including RVO.
Go on ..
At the same time, RVO is not always driven by traditional cardiovascular risk factors alone—as clinical reviews have highlighted the importance of considering systemic contributors beyond hypertension and diabetes in select cases.
The authors of this current study also emphasized that ocular findings may reflect underlying systemic disease activity, making retinal examination clinically important in some leukemia patients.
So what exactly did this meta-analysis look at?
Researchers conducted a systematic review and meta-analysis following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and evaluated observational studies examining ocular findings in leukemia patients.
Specifically, the investigators analyzed:
- Ocular manifestations overall
- Retinal hemorrhages
- Retinal infiltration
- RVO
- Visual outcomes following treatment
To note: Case reports were also reviewed narratively, although they were excluded from the pooled quantitative analysis.
Who was included in the analysis?
The review included:
- Eight clinical studies
- 1,016 participants
- Patient populations from India, Nigeria, Pakistan, and the United States
While the included studies varied in design, population characteristics, and diagnostic methods, they all examined ocular findings associated with leukemia.
What did the researchers actually find?
The biggest finding was that ocular involvement was relatively common overall.
Across the pooled analysis:
- Approximately 42% of leukemia patients demonstrated ocular manifestations
- Retinal hemorrhages were the most common finding, occurring in roughly 13% to 15% of patients
- Retinal infiltration occurred in approximately 3%
- RVO occurred in roughly 1.2%
So while RVO itself remained relatively uncommon, broader retinal involvement was far more frequent.
The authors noted that retinal hemorrhagic changes were among the earliest and most common ocular indicators of leukemia.
So how does leukemia end up affecting retinal circulation?
The study authors described several overlapping mechanisms that may contribute to retinal vascular compromise:
One involves hyperviscosity and leukostasis, particularly in patients with markedly elevated leukocyte counts. Excess circulating leukemic cells can impair microvascular blood flow and disrupt retinal perfusion.
The authors noted that these abnormalities may:
- Hinder retinal circulation
- Contribute to venous occlusion
- Worsen vascular instability
Leukemic infiltration may also directly involve retinal vessels or the optic nerve itself in some patients.
Additional reviews of leukemic retinopathy have similarly described retinal hemorrhages, venous stasis, and vascular occlusion as possible consequences of hyperviscosity and retinal infiltration during active leukemia.
Could retinal findings really appear before leukemia is diagnosed?
In some cases, yes. One of the more clinically important observations in the analysis was that ocular findings may precede obvious systemic symptoms in certain patients.
Here's what a retinal examination may occasionally reveal before leukemia has formally been diagnosed:
- Hemorrhages
- Vascular abnormalities
- Infiltrative retinal findings
- Optic nerve involvement
The study also highlighted that ocular findings may parallel systemic disease activity, reinforcing the importance of communication between ophthalmology and hematology.
Visual outcomes varied considerably across reported cases, ranging from complete vision loss to substantial recovery after leukemia-directed therapy. According to the authors, that variability suggests earlier recognition and systemic treatment may improve ocular outcomes in selected patients.
Are there any important limitations here?
Yes. First, the included studies varied considerably in:
- Study design
- Patient populations
- Diagnostic methods
- Definitions of ocular involvement
Many studies were also single-center and hospital-based, which may have limited generalizability.
Additionally, as RVO itself remained relatively uncommon in the pooled analysis, larger prospective studies will likely be needed to better define the true relationship between leukemia and retinal vascular occlusion risk.
The authors also acknowledged that inconsistent diagnostic criteria across studies made it more difficult to standardize outcome measurements.
What does this mean clinically for ECPs?
The findings do not suggest that leukemia is a common cause of retinal vein occlusion overall.
But they do reinforce that atypical retinal vascular findings may occasionally warrant broader systemic consideration, particularly when:
- Patients are younger
- Traditional vascular risk factors are absent
- Retinal hemorrhages appear disproportionate
- Hematologic abnormalities are present
The authors advocated for routine ophthalmic screening in leukemia patients, including:
- Fundus examination
- Optical coherence tomography (OCT)
- OCT angiography (OCTA)
They also emphasized that ocular findings may serve as noninvasive biomarkers of systemic leukemic activity.