Retina and macula · 08
Floaters and retinal detachment risk
New flashes or more floaters: same-day dilated assessment
Last reviewed: 2026-10-03 · 潘家健醫生
Key points
- Floaters are often vitreous opacities; new or suddenly more floaters are not for self-diagnosis as “just floaters.”
- New flashes or a clear increase in floaters: same-day dilated exam when possible.
- A curtain or sudden blindness: go to A&E now.
- Whether a tear needs laser is decided after dilation; detachment is not “go home and wait for laser.”
What it is
The vitreous liquefies and collagen clumps cast shadows (floaters). Most are posterior vitreous detachment. A few warn of a retinal tear or bleed. High myopia (≥ 600 degrees) can bring this on in the 20s–30s, with higher tear/detachment risk.
Often benign — still needs a doctor to confirm
- A few stable specks or threads for years
- They drift with the eye; no field cut
- No flashes; vision unchanged
- A dilated exam has already ruled out a tear
Same-day dilated exam (see an ophthalmologist as soon as possible)
- A sudden shower of new specks
- Frequent flashes, especially in the dark
Go to A&E now (curtain or sudden vision loss)
- A curtain or shadow over the field
- Any sudden sharp drop in vision
What a doctor may discuss
- New or suddenly more floaters need a same-day dilated exam; do not self-diagnose. A curtain or sudden loss of vision is A&E.
- Most benign floaters are observed; the brain may notice them less over months.
- YAG vitreolysis is not routine.
- Vitrectomy can clear floaters but speeds cataract and has detachment risk — only if life is badly affected and a doctor agrees it is appropriate.
- Tear risk depends on type: a symptomatic horseshoe tear with traction is high risk; asymptomatic atrophic or operculated holes are lower. Laser is decided after dilation, not by a single percentage.
- If a doctor suggests barrier laser, the order of the day is on The day of argon retinal barrier laser. YAG vitreolysis is a different matter and is not routine.
Related public education video (HKOS)
Video source: Hong Kong Ophthalmological Society (HKOS) “Eyes Decoded” YouTube (public education)
This site is not affiliated with, and is not the same organisation as, the Hong Kong Ophthalmological Society (HKOS).
Selected public references (not a full bibliography)
These are the public studies this page draws on. PMID links go to PubMed (US National Library of Medicine) so you can check them. Figures are from those studies — not your prognosis and not a clinic success rate. Links are not a shop.
- Hollands H, Johnson D, Brox AC, et al. Acute-onset floaters and flashes: is this patient at risk for retinal detachment?. JAMA. 2009;302(20):2243-2249. PMID 19934426急性閃光／飛蚊須散瞳排除裂孔。有簾幕或突然失明按急症處理。
This is general medical information, not a diagnosis, and cannot replace an in-person consultation with a registered ophthalmologist, refraction, or a dilated fundus exam. It is not advice to use any medicine or undergo any procedure. Medicines (including off-label use), laser or surgery must be decided by a registered doctor after examination, according to indications and Hong Kong registration. Figures from the literature are published averages, not any clinic’s results. This site does not book, prescribe or refer. Do not change treatment on your own.