What causes corrugations in fresh retinal detachment?

Corrugations in Fresh Retinal Detachment

Corrugations in fresh retinal detachment occur due to outer retinal compression from progressive hydration and lateral expansion when the retinal pigment epithelium (RPE) loses control of the subretinal space for more than 2 days, causing a reduction in the outer retina's elastic modulus relative to the inner retina. 1

Pathophysiologic Mechanism

The development of outer retinal corrugations (ORCs) follows a specific sequence of events:

• Acute exposure of the subretinal space to liquified vitreous through a retinal break initiates the process 1
• RPE-photoreceptor dysregulation occurs when the RPE pump capacity is overwhelmed by the volume of fluid entering the subretinal space 1
• Progressive outer retinal hydration leads to lateral expansion of the outer retinal layers 1
• Differential elastic properties develop, with the outer retina's modulus of elasticity reducing to approximately 0.05 to 0.5 relative to the inner retina 1

Critical Time Factor

The duration of RPE-photoreceptor dysregulation is crucial:

• ORCs develop when dysregulation persists for at least 2 days 1
• All eyes with ORCs (100%, 32/32) demonstrated RPE-photoreceptor dysregulation for this minimum duration 1
• Eyes without ORCs either had nonprogressive detachments or RPE-photoreceptor dysregulation for fewer than 2 days 1

Clinical Characteristics Associated with ORCs

Acute, progressive, and extensive retinal detachments are the hallmark presentation:

• More than half (60.6%) of patients with rhegmatogenous retinal detachment present with fovea-off detachments 1
• Nearly half (48.4%) demonstrate ORCs at initial presentation 1
• The corrugated appearance on optical coherence tomography results from the outer retina being thrown into folds due to intrinsic compressive forces 1

Biomechanical Explanation

The corrugations represent a mechanical buckling phenomenon:

• When the outer retina becomes hydrated and expands laterally while the inner retina maintains its structural integrity, compressive forces develop 1
• The reduced elastic modulus of the outer retina (0.05 to 0.5 relative to inner retina) allows it to buckle under these compressive forces 1
• This creates the characteristic corrugated or folded appearance seen on cross-sectional imaging 1

Clinical Significance

ORCs have important prognostic implications:

• When ORCs persist after retinal reattachment, they become outer retinal folds associated with worse functional outcomes 1
• Understanding this pathophysiology emphasizes the importance of prompt surgical intervention to minimize the duration of RPE-photoreceptor dysregulation 1
• The 2-day threshold suggests a critical window for intervention to potentially prevent permanent corrugation formation 1

Comparison to Epiretinal Membrane Corrugations

While the question asks about fresh retinal detachment, it's worth noting that corrugations can also occur from tangential traction in epiretinal membranes, where the membrane is attached by pegs to the inner retinal surface with intervening hyporeflective spaces, creating a different type of corrugated appearance 2. However, in fresh rhegmatogenous retinal detachment, the mechanism is fundamentally different—driven by outer retinal hydration and compression rather than surface traction.