Prevalence of Pachychoroid
Pachychoroid features are remarkably common, affecting approximately 61% of fellow eyes in patients with unilateral central serous chorioretinopathy (CSC), with an additional 30.8% showing uncomplicated pachychoroid changes. 1
Population-Specific Prevalence Data
The most robust prevalence data comes from a large retrospective study of 536 patients with CSC, which provides the clearest window into pachychoroid frequency 1:
In unilateral CSC patients (282 patients): 1
- 61% had pachychoroid pigment epitheliopathy (PPE) in the fellow eye
- 30.8% had uncomplicated pachychoroid (UCP)
- Only 8.2% had completely normal fellow eyes
Bilateral CSC occurred in 47.4% of all CSC patients, suggesting widespread pachychoroid substrate 1
Male predominance is notable, with a female to male ratio of 1:2.8 in CSC patients, which reflects the underlying pachychoroid population 1
Clinical Spectrum Considerations
The true prevalence of pachychoroid is likely underestimated because it represents a disease spectrum rather than a single entity 2, 3. The spectrum includes multiple phenotypes that may not always be clinically apparent 4:
- Central serous chorioretinopathy (most commonly recognized)
- Pachychoroid pigment epitheliopathy
- Pachychoroid neovasculopathy
- Polypoidal choroidal vasculopathy
- Peripapillary pachychoroid syndrome
- Focal choroidal excavation
The presence of pachyvessels (dilated Haller's layer vessels) is the defining feature, not necessarily increased choroidal thickness, which means pachychoroid can exist even with normal subfoveal choroidal thickness measurements 4, 5.
Age and Bilateral Disease Patterns
Bilateral pachychoroid manifestations increase with age, particularly in patients over 50 years 6:
- 50% prevalence of bilateral CSC in patients ≥50 years old
- 28% prevalence in patients <50 years old
- Up to 84% bilateral disease activity in severe chronic CSC phenotypes 6
Important Clinical Pitfalls
Do not assume normal choroidal thickness excludes pachychoroid disease 4, 5. The pathognomonic finding is the presence of dilated choroidal vessels (pachyvessels) with overlying choriocapillaris attenuation, which can occur regardless of absolute choroidal thickness 5.
The 61% prevalence of PPE in fellow eyes means that when you diagnose unilateral CSC, you should actively look for subclinical pachychoroid changes in the apparently normal fellow eye 1. These eyes show characteristic RPE bumps (77.3% of PPE eyes) and pigment epithelial detachments (43% of PPE eyes) on careful OCT examination 1.
There were no significant demographic differences between patients with PPE, uncomplicated pachychoroid, and normal eyes regarding age, disease duration, sex, hypertension, steroid use, or refractive error 1, suggesting pachychoroid represents an intrinsic choroidal phenotype rather than an acquired condition from specific risk factors.