RCOphth Annual Congress 2026

Background

•Retinal vascular anomalies are rare congenital variants.

•Often identified incidentally during routine fundus imaging.

•Can mimic serious pathology → risk of over-investigation.

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Key entities:

•Situs inversus of retinal vessels (SIRV)

•Congenital retinal macrovessel (CRM)

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SIRV

•Congenital misdirection of retinal vessels (nasal emergence).

•~80% cases are bilateral.

•Linked to abnormal optic stalk–vesicle development.

CRM

•Large aberrant vessel crossing macula (usually venous).

•Embryological vascular development error (weeks 15–16).

Aim

To determine the incidental detection rate and clinical characteristics of retinal vascular anomalies in a medical retina cohort.

Methods

Retrospective observational study

Image Selection Criteria

Inclusion

•Clear optic disc & macula

•High-resolution images

Exclusion

•Media opacity

•Poor focus

•Limited field of view

Results

Detection Rate = 1.2%

Subtype breakdown

•SIRV = 0.8% (4 eyes) -> 2 patients identified, bilateral nasal vessel emergence, findings consistent with previously reported bilateral prevalence.

•CRM = 0.4% (2 eyes) -> 1 patient identified, bilateral aberrant macrovessel crossing the macula, represents an uncommon bilateral presentation.

Clinical Relevance

Diagnostic Pitfalls

SIRV may mimic : optic disc hypoplasia, tilted disc, pseudopapilloedema.

CRM may mimic: AV malformations, macular telangiectasia, BRVO.

Why It Matters

Risk of:

•Over-referral

•Unnecessary imaging

•Patient anxiety

Recognition improves diagnostic confidence

Key Context

•SIRV prevalence consistent with literature (0.2–0.5%).

•CRM extremely rare (~1 in 200,000); bilateral cases uncommon.

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Conclusion

•SIRV and CRM are rare, benign retinal vascular anomalies.

•Often incidental and asymptomatic.

•Can mimic significant pathology if unrecognised.

TAKE HOME MESSAGE

Retinal vascular anomalies are rare, benign variants that can mimic pathology—recognition is essential to avoid over-investigation and improve diagnostic confidence.

RCOphth Annual Congress 2026

Retinal Vessel Anomalies- A Retrospective Study

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