Definitions and Types of Retinal Detachment
Retinal detachment is defined as a separation of the neurosensory retina from the underlying retinal pigment epithelium, which can be categorized into three main types: rhegmatogenous, exudative, and tractional. 1, 2
Types of Retinal Detachment
1. Rhegmatogenous Retinal Detachment (RRD)
- Definition: A separation of the retina from the retinal pigment epithelium caused by fluid passing from the vitreous cavity into the subretinal space through a break in the retina (from Greek rhegma, "rent") 1
- Mechanism: Results from retinal breaks caused by vitreoretinal traction 2
- Prevalence: Most common type, occurring in approximately 10-18 per 100,000 persons annually 2
- Associated with:
- Posterior vitreous detachment (PVD)
- Retinal breaks/tears
- Lattice degeneration
2. Exudative Retinal Detachment
- Definition: Develops when fluid collects in the subretinal space due to disruption of the blood-retinal barrier 3
- Mechanism: No retinal breaks; instead caused by inflammatory, infectious, infiltrative, neoplastic, vascular, or degenerative conditions 3
- Characteristics:
- Shifting fluid that moves with changes in head position
- Often bilateral
- No retinal tears or holes
3. Tractional Retinal Detachment
- Definition: Occurs when fibrovascular tissue pulls the neurosensory retina away from the retinal pigment epithelium
- Mechanism: Mechanical forces from fibrous or fibrovascular proliferations in the vitreous cavity
- Associated with:
- Proliferative diabetic retinopathy
- Proliferative vitreoretinopathy
- Retinopathy of prematurity
Key Related Definitions
Retinal Breaks
- Definition: Full-thickness defects in the retina 1
- Types:
- Retinal tears: Caused by vitreoretinal traction
- Round retinal holes: Round defects unassociated with vitreoretinal traction
- Operculated retinal tear/break: Defect caused by vitreoretinal traction that pulls a circular piece of retinal tissue (operculum) free from the retinal surface 1
- Horseshoe tear: Retinal tear caused by vitreoretinal traction, shaped like a horseshoe due to a flap of torn tissue that remains attached to the detached vitreous gel 1
- Retinal dialysis: Specific type of crescentic peripheral retinal break at the ora serrata, usually associated with trauma 1
Posterior Vitreous Detachment (PVD)
- Definition: Separation of the posterior vitreous cortex from the internal surface of the retina 1
- Characteristics:
- Usually occurs as an acute event after age-related vitreous liquefaction
- Separation extends rapidly to the posterior margin of the vitreous base
- May cause retinal breaks if vitreoretinal adhesions are present
- Diagnosed by slit-lamp biomicroscopy showing a prominent plane defining the posterior vitreous face
- Presence of a glial annulus (Weiss ring) is strong evidence of PVD 1
Subclinical Retinal Detachment
- Definition: A retinal detachment that extends more than 1 disc diameter from the posterior edge of the retinal break, less than 2 disc diameters from the equator, and does not impair the field of vision 1
Vitreoretinal Adhesion (VMA)
- Definition: A firm attachment between the cortical vitreous and the inner surface of the retina 1
- Clinical significance: Traction during PVD may cause retinal breaks at these sites
Vitreomacular Traction (VMT)
- Definition: Partial vitreous separation from the retina resulting in mechanical distortion of the macula 1
Lattice Degeneration
- Definition: A peripheral vitreoretinal lesion characterized by retinal thinning, overlying vitreous liquefaction, and firm vitreoretinal adhesions at its margins 1
- Characteristics:
- Most lesions are ovoid with long axes parallel to the ora serrata
- Round holes frequently occur within lattice lesions
- Horseshoe tears typically occur at the margins of lattice lesions during PVD
- Predisposes to retinal tears and detachment
Genetic Associations
- Stickler syndrome: Most common inherited vitreoretinal disorder associated with RRD 1
- Ocular features: high myopia, retrolental/transvitreal/epiretinal membranes, chorioretinal pigment alterations, lattice degeneration
- Systemic features: skeletal dysplasia, marfanoid habitus, flattened facies, cleft palate
- Inheritance: autosomal dominant, related to COL2A1 gene defect
Understanding these definitions and types is crucial for proper diagnosis, risk assessment, and management of retinal detachment, which remains one of the few true ophthalmic emergencies requiring prompt intervention to preserve vision.