Retinal Detachment Types
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Direct answer
Retinal detachment is separation of the neurosensory retina from the retinal pigment epithelium, and its three mechanisms define its three types: rhegmatogenous, where fluid enters through a hole or tear (the commonest type, after posterior vitreous detachment, lattice degeneration, trauma or aphakia); tractional, where vitreoretinal membranes in proliferative diabetic retinopathy pull the retina off without a break; and exudative or serous, where fluid accumulates beneath an intact retina from choroidal tumours, inflammation like Vogt-Koyanagi-Harada or posterior scleritis. Warning symptoms of the rhegmatogenous type — sudden flashes, a shower of floaters, then a spreading curtain — are an emergency because an attached macula decides the outcome; surgery is scleral buckling, vitrectomy or pneumatic retinopexy with laser or cryotherapy to seal the break.
What you must remember
- Three types, three mechanisms: rhegmatogenous — a full-thickness retinal break lets liquefied vitreous beneath the retina; tractional — contracted fibrovascular membranes drag the retina; exudative — subretinal fluid from leaky choroidal vessels with no break; identifying the type is the diagnostic task, because treatments diverge.
- Rhegmatogenous risk profile: posterior vitreous detachment of age, lattice degeneration, high myopia, previous cataract surgery, trauma and fellow-eye history; the horseshoe tear at the posterior edge of the vitreous base is the classic culprit.
- Symptom triage that saves the macula: photopsia (flashes), new floaters (vitreous haemorrhage or pigment), and a shadow or curtain progressing as detachment extends — any combination warrants urgent dilated examination with indentation; a curtain crossing the centre means the macula is newly off.
- Signs: the detached retina loses transparency, ballooning grey with folds that shift with eye movement; the break is found by systematic search; tobacco dust (Shafer sign) is strong evidence of a break; intraocular pressure is often low.
- Tractional detachment logic: proliferative diabetic retinopathy is the archetype; the detachment has a concave, taut configuration with no shifting fluid, and treatment is vitrectomy with membrane peel plus endolaser, often after preoperative anti-VEGF; a shallow stable detachment can be observed.
- Exudative detachment logic: shifting subretinal fluid that re-deploys with posture, an absent break, and a cause-seeking workup — B-scan for a choroidal mass (melanoma, haemangioma), inflammatory markers for VKH and posterior scleritis; treatment is of the underlying lesion, never retinal surgery.
- Surgical menu: scleral buckling (cryopexy plus silicone explant) for suitable superior peripheral breaks; pars plana vitrectomy with gas or oil for complex, giant tear or tractional cases; pneumatic retinopexy for selected superior small breaks; laser demarcation for small stable ones.
- Postoperative realities: positioning with gas tamponade, no air travel with intraocular gas (expansion at altitude), cataract after vitrectomy, re-detachment risk — and examination of the fellow eye with prophylactic treatment of high-risk lattice.
How to work through a curtain across the vision
A 62-year-old myopic man reports a week of flashes and floaters, then since yesterday a grey curtain rising from below; vision is 6/18 with a superior field restriction. Walk the pathway: urgency first — the curtain's edge has not crossed fixation, so the macula may still be on; dilate and examine with indirect ophthalmoscopy and indentation: a grey, mobile superior bullous detachment tracks a horse-shoe tear at 11 o'clock with tobacco dust. The operation follows the break: a superior break suits scleral buckling with cryotherapy, while many units favour vitrectomy with gas in the pseudophakic; either way, the aim is to close the break, not to "drain fluid". Contrast him with the 38-year-old with poorly controlled type 1 diabetes whose dense fibrovascular membranes have tented the inferior retina in a concave, immobile dome: that is tractional detachment — vitrectomy with membrane peeling and endolaser. And a dome-shaped detachment with shifting fluid, no break and a cannon-ball shadow on ultrasound is a choroidal melanoma — where "retinal detachment" stops being a diagnosis and becomes a sign.
Where students slip
The commonest error is treating "retinal detachment" as a single disease with a single operation — examiners build stems around the type, and "buckle" answered to a diabetic tractional or an exudative detachment of VKH is wrong twice over. The second slip is missing the acute posterior vitreous detachment: not every flash-floater presentation is a detachment, but every one needs a peripheral examination to exclude a tear — sealing a fresh tear with laser before fluid tracks beneath it is the cheapest sight-saving procedure in ophthalmology.
Frequently asked questions
What distinguishes the three types of retinal detachment?
Rhegmatogenous has a retinal break with fluid entry; tractional has vitreoretinal pulling, classically from proliferative diabetic membranes; exudative has subretinal fluid from choroidal disease with an intact retina.
What is Shafer sign?
Tobacco dust — pigment granules in the anterior vitreous — strongly suggesting a retinal break, hence a rhegmatogenous detachment.
Why does exudative detachment show shifting fluid?
The subretinal fluid is serous and mobile, redistributing with posture to the dependent position, unlike the fixed configuration of rhegmatogenous or tractional detachments.
Which operations treat rhegmatogenous detachment?
Scleral buckling with cryotherapy, vitrectomy with gas or oil tamponade, and pneumatic retinopexy for selected superior breaks — all aimed at closing the causative break.
Why is macular status the key prognostic factor?
A detachment sparing the macula retains good central vision with prompt surgery; once it detaches, final acuity is limited by photoreceptor damage — hence the urgency of the curtain presentation.