Vitreous Gel Liquefaction (Syneresis)
Collagen scaffolding loosens, turning gel into pockets of liquid.
- 40+: Onset age (gradual with aging)
- ↑: Gel water content (liquefaction pockets form)
- Silent: Symptom stage (usually unnoticed)
- Syneresis: Process (collagen-hyaluronan split)
What happens to the gel
Collagen fibrils clump while hyaluronan pools into liquid pockets.
Posterior Hyaloid Membrane Separation
Liquefied vitreous seeps behind the face, peeling it off the retina.
- 50–70y: Peak incidence (typical PVD age range)
- Posterior→anterior: Direction (peel pattern)
- ~2 yrs apart: Bilaterality (second eye often follows)
- Earlier onset: Myopia link (in nearsighted eyes)
Peel mechanics
The membrane detaches gradually, often starting near the optic disc.
Floater Appearance and Perception
Condensed vitreous strands cast moving shadows on the retina.
- Rings, cobwebs: Common shapes (Weiss ring classic)
- Drifting lag: Perceived motion (follows eye movement)
- ~76%: Prevalence (lifetime by some estimates)
- Bright backgrounds: Visibility (sky, white walls)
Why floaters appear
Clumped collagen fibers block light, casting shadows onto the retina.
Photopsia — Flashes of Light from Traction
Mechanical tugging on the retina fires the retina, seen as flashes.
- Peripheral arcs: Flash pattern (lightning-streak sensation)
- Eye movement: Trigger (or traction episodes)
- Seconds: Duration (per flash episode)
- Moderate: Concern level (warrants eye exam)
Why flashes occur
Traction mechanically stimulates the retina, which the brain reads as light.
Retinal Tear Risk Assessment
Sustained focal traction can tear the retina at a weak point.
- 10–15%: Tear risk w/ PVD (develop a retinal tear)
- Can progress: Untreated tear (to retinal detachment)
- New flashes/floaters: Warning signs (sudden shower of floaters)
- Dilated exam: Action (within 24–48 hours)
When to seek care
Sudden floater showers or curtain-like shadow need urgent evaluation.
Seek same-day eye care for sudden flashes, floater showers, or a shadow.