Retina Note · Retinal Detachment Surgery · Part 1
Principles of Retinal Detachment Surgery
Vitrectomy, subretinal-fluid drainage, fluid–air exchange and perfluorocarbon liquid
Rhegmatogenous retinal detachment surgery succeeds by treating the causative retinal break, relieving clinically relevant traction and restoring stable contact between the neurosensory retina and the retinal pigment epithelium.
Watch the lecture
Watch Part 1 first, then use this companion note to consolidate the operative principles of vitrectomy, subretinal-fluid drainage, fluid–air exchange and PFCL.
Insight Ophthalmology: Principles of Retinal Detachment Surgery — Part 1
What Must RRD Surgery Achieve?
Every rhegmatogenous retinal detachment operation must address four connected objectives. The procedure may differ, but these principles remain the same.
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1
Identify all causative retinal breaks
Every full-thickness break permitting fluid entry into the subretinal space must be found and addressed.
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2
Relieve clinically relevant traction
Vitreoretinal traction acting on or around the break must be neutralised so that the break can remain closed.
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3
Restore retinal–RPE apposition
The detached neurosensory retina must be brought back into contact with the retinal pigment epithelium.
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4
Maintain closure while adhesion develops
Tamponade or buckle support maintains break closure while retinopexy produces a durable chorioretinal adhesion.
Choosing the Operative Approach
Procedure selection depends on the complete configuration of the detachment rather than one isolated feature. Lens status, break location, vitreous condition, proliferative vitreoretinopathy and patient factors must be considered together.
| Approach | Main mechanism | Commonly favoured situations |
|---|---|---|
| Pars plana vitrectomy | Removes vitreous traction and permits internal drainage, retinopexy and tamponade. |
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| Scleral buckle | Indents the eyewall beneath the break and reduces traction acting across it. |
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| Pneumatic retinopexy | Uses an intraocular gas bubble to support a treated retinal break. |
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What Pars Plana Vitrectomy Contributes
Pars plana vitrectomy removes vitreous from the posterior segment and creates internal access for retinal repair. Its value lies not in simply clearing the vitreous cavity, but in allowing the surgeon to address the break, traction, subretinal fluid and tamponade in a controlled sequence.
Think of vitrectomy as the internal platform that makes the remaining stages of retinal-detachment repair possible.
Clears media opacity
Vitreous haemorrhage, dispersed pigment or other opacity can be removed to improve visualisation of the retina.
Improves peripheral visualisation
The peripheral retina can be examined internally to identify causative, additional or previously hidden retinal breaks.
Relieves vitreoretinal traction
Vitreous attached to the margins or flap of a retinal tear can be carefully trimmed so the break is no longer held open.
Enables internal drainage
Subretinal fluid can be drained through an existing break or, when required, through a deliberately created drainage retinotomy.
Permits endolaser
Once the retina is flattened, laser photocoagulation can be applied internally around the causative retinal break.
Allows internal tamponade
Air, expansile gas or silicone oil can maintain break support while chorioretinal adhesion develops.
Relieving Traction Around the Break
A horseshoe retinal tear commonly forms where the posterior vitreous remains attached to a flap of retina. Continued traction at this point can hold the break open or extend it.
Vitreous remains attached to the tear
Persistent pull on the flap and margins can keep the retinal break open and permit continued passage of fluid into the subretinal space.
The break can settle without continued pull
Vitreous around the break is carefully trimmed so that the tear is no longer being held open by persistent vitreoretinal traction.
What the surgeon addresses
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01
Core vitreous
Central vitreous is removed to create space and improve access to the posterior segment.
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02
Posterior hyaloid
Its attachment is assessed, and posterior vitreous separation may be induced or extended when required.
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03
Peripheral vitreous
Residual vitreous is trimmed carefully around the causative retinal break.
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04
Vitreous base
Firmly adherent peripheral vitreous is shaved rather than forcibly stripped from the retina.
Why Drain Subretinal Fluid?
Subretinal fluid separates the neurosensory retina from the underlying retinal pigment epithelium. Removing sufficient fluid can restore retinal–RPE apposition and make the remaining stages of repair more controlled.
Restores retinal apposition
The detached neurosensory retina is brought closer to the RPE so the break can be treated and supported.
Improves break treatment
A flatter retina allows more accurate laser application around the causative retinal break.
Reduces retinal folds
Controlled drainage helps the retina settle smoothly and may reduce residual folds or displacement.
Prepares for tamponade
Restoring apposition allows air, gas or silicone oil to support the treated break effectively.
What happens once the break is closed?
Internal and External Drainage
Subretinal fluid can be drained from outside the eye during scleral buckling or internally during pars plana vitrectomy. The route is chosen according to the operation, break location, fluid configuration and the desired surgical endpoint.
| Feature | External drainage | Internal drainage |
|---|---|---|
| Route | Through a controlled trans-scleral drainage site into the subretinal space. | Through an existing retinal break or a deliberately created drainage retinotomy. |
| Usually associated with | Scleral-buckle surgery | Pars plana vitrectomy |
| Main advantage | Provides immediate flattening during an external retinal repair. | Allows directly visualised and controlled drainage during internal surgery. |
| Important risks |
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|
Fluid–Air Exchange
After vitrectomy, the vitreous cavity is filled with balanced salt solution. During fluid–air exchange, this intraocular fluid is progressively replaced by air, allowing subretinal fluid to be removed and the detached retina to settle against the RPE.
Core definition
Fluid–air exchange is the controlled replacement of fluid within the vitreous cavity by air during vitreoretinal surgery.
What happens during the exchange?
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1
Air enters the eye
Air is infused into the vitreous cavity as balanced salt solution is removed.
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2
Fluid is displaced
Intraocular and subretinal fluid moves toward the selected drainage route.
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3
Fluid is aspirated
Subretinal fluid is removed through an existing break or drainage retinotomy.
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4
Retina reapposes
The neurosensory retina settles against the retinal pigment epithelium.
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5
Break treatment follows
The flattened retinal break can then be treated accurately with retinopexy.
Drainage
The exchange permits removal of intraocular fluid and sufficient subretinal fluid to flatten the retina.
Retinal apposition
Air replaces fluid and helps establish contact between the retina and RPE before retinopexy and final tamponade.
Internal Drainage During PPV
During pars plana vitrectomy, subretinal fluid can be drained through the causative retinal break or through a deliberately created drainage retinotomy. The existing break is preferred whenever it provides safe and effective drainage.
When might a drainage retinotomy be needed?
- The causative retinal break is too anterior for controlled aspiration.
- Subretinal fluid does not reach the existing break.
- Complete flattening is needed before accurate retinopexy.
- The retinal configuration prevents safe drainage through the original break.
When PFCL Helps
Some retinal detachments are too bullous, mobile or folded to be controlled easily with air alone. Perfluorocarbon liquid provides temporary intraoperative stability while the retina is flattened, drained and treated.
A temporary heavy liquid
PFCL is optically clear and heavier than aqueous fluid. It settles posteriorly over the retina and provides controlled mechanical support during surgery.
By flattening the posterior retina, PFCL displaces subretinal fluid toward peripheral retinal breaks. It also stabilises the retina while peripheral vitreous is trimmed and retinopexy is applied.
Situations in which PFCL may be useful
- Bullous retinal detachment: helps flatten a highly elevated retina against the RPE.
- Giant retinal tear: helps unfold and stabilise the mobile posterior retinal flap.
- Folded or mobile retina: reduces retinal movement during intraocular manipulation.
- Proliferative vitreoretinopathy: stabilises the retina while tractional membranes or retinal shortening are addressed.
- Peripheral vitreous dissection: keeps the posterior retina flattened during vitreous-base shaving.
- Anteriorly located retinal breaks: displaces posterior subretinal fluid anteriorly toward the break for drainage.
Important Properties of PFCL
The clinical usefulness of perfluorocarbon liquid comes from a small set of physical properties. Each property contributes to safe retinal flattening, stabilisation and controlled intraoperative manipulation.
| Property | What it means | Why it helps |
|---|---|---|
| Optically clear | The retina remains visible through the PFCL bubble. | Allows continued visualisation, peripheral vitreous work and laser treatment while the retina remains stabilised. |
| High specific gravity | PFCL is substantially heavier than aqueous fluid. | It settles posteriorly, flattening the retina and displacing subretinal fluid toward peripheral breaks. |
| Low viscosity | The liquid flows readily through small-gauge instruments. | Facilitates controlled injection and aspiration during vitreoretinal surgery. |
| High interfacial tension | PFCL tends to remain separate from aqueous fluid as a cohesive intraocular bubble. | Reduces fragmentation into multiple small droplets and supports controlled retinal manipulation. |
PFCL-Assisted Retinal Flattening
PFCL is introduced slowly over the posterior pole after clinically relevant traction has been relieved. As the bubble enlarges, it progressively flattens and stabilises the posterior retina while directing subretinal fluid toward a drainage route.
What happens as PFCL is introduced?
- Posterior injection: PFCL is introduced slowly so that a cohesive bubble forms over the posterior pole.
- Retinal flattening: its weight brings the mobile neurosensory retina into contact with the underlying RPE.
- Fluid displacement: subretinal fluid moves ahead of the enlarging PFCL bubble toward a peripheral retinal break or selected drainage route.
- Peripheral dissection: the stabilised retina permits controlled vitreous-base shaving and relief of residual traction.
- Retinopexy: because PFCL is optically clear, laser may be applied while the retina remains flattened and stabilised.
Shifting Subretinal Fluid
As the PFCL bubble enlarges, posterior subretinal fluid is displaced anteriorly ahead of it. This mobile fluid is often described as shifting subretinal fluid.
- PFCL settles posteriorly and begins to flatten the detached retina.
- Subretinal fluid moves anteriorly ahead of the expanding PFCL bubble.
- The fluid should ideally exit through the causative retinal break.
- If fluid remains trapped and prevents complete flattening, a drainage retinotomy may be required.
Drain through the existing break
When the displaced fluid reaches the causative break, it can be aspirated without creating another retinal opening.
Consider a drainage retinotomy
A separate retinotomy is used only when necessary to achieve controlled drainage and adequate retinal flattening.
Removing PFCL
PFCL is usually removed after it has completed its intraoperative role. The aim is to aspirate the heavy liquid completely while preserving retinal apposition and controlled break support.
Principles of PFCL removal
- Aspiration begins from the most dependent PFCL: residual liquid commonly collects over the posterior pole.
- The retina is kept stable during exchange: abrupt aspiration or loss of apposition should be avoided.
- Small residual bubbles are sought carefully: PFCL may remain around the posterior pole or beneath retinal folds.
- Balanced salt solution may be reintroduced: this can help small PFCL droplets coalesce before further aspiration.
PFCL–air exchange
Air replaces PFCL as the heavy liquid is aspirated from the posterior cavity.
PFCL–gas exchange
Gas may provide the final internal tamponade after PFCL removal.
PFCL–silicone oil exchange
Silicone oil may replace PFCL directly when prolonged support is required in a complex detachment.
Treating the Retinal Break
Once traction has been relieved and the retina flattened, the causative retinal break is surrounded with retinopexy. This creates a controlled chorioretinal reaction that strengthens into a durable adhesion.
Laser photocoagulation
Endolaser is commonly applied during pars plana vitrectomy once the retina is sufficiently flattened for accurate treatment around the retinal break.
Cryotherapy
Cryotherapy may be used for very anterior retinal breaks or during scleral-buckle surgery when external treatment is more practical.
Part 2 explains how laser and cryotherapy differ, why tamponade is required, and how gas, silicone oil, scleral buckling and pneumatic retinopexy maintain retinal support.
Part 1 Summary
Key principles
- Successful RRD repair addresses the retinal break, vitreoretinal traction and retinal apposition.
- Pars plana vitrectomy permits internal visualisation, traction release, subretinal-fluid drainage, retinopexy and tamponade.
- Subretinal fluid may be drained internally, externally or allowed to absorb gradually once the causative break has been closed.
- Fluid–air exchange restores retinal apposition and prepares the eye for retinopexy and final tamponade.
- PFCL is a temporary intraoperative heavy liquid used to flatten and stabilise mobile or complex retina and direct subretinal fluid toward a drainage route.
- Retinopexy initiates chorioretinal adhesion, but the retinal break must remain supported while that adhesion strengthens.
References
The clinical principles in this companion note were checked against the following reviews, comparative studies and surgical literature.
- Warren A, et al. Contemporary management of primary rhegmatogenous retinal detachment. Clinical & Experimental Ophthalmology. 2023. doi:10.1111/ceo.14205
- Popovic MM, et al. Surgical management of rhegmatogenous retinal detachment: contemporary techniques and evidence. Survey of Ophthalmology. 2022. doi:10.1016/j.survophthal.2021.05.008
- Heimann H, et al. Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment: results of a prospective randomised multicentre clinical study. Ophthalmology. 2007. doi:10.1016/j.ophtha.2007.09.013
- Grad O, et al. Contemporary outcomes and operative considerations in rhegmatogenous retinal detachment repair. Retina. 2024. doi:10.1097/IAE.0000000000004083
- Vo LV, et al. Drainage of subretinal fluid during rhegmatogenous retinal detachment repair. Journal of VitreoRetinal Diseases. 2020. doi:10.1177/2474126420941372
- Georgalas I, et al. Heavy liquids in vitreoretinal surgery: indications, properties and complications. Seminars in Ophthalmology. 2011. doi:10.3109/15569527.2011.560915
- Yu Q, et al. Perfluorocarbon liquids in vitreoretinal surgery: applications and complications. Journal of Ophthalmology. 2014. doi:10.1155/2014/250323
- Liu W, et al. Subretinal perfluorocarbon liquid: clinical significance and surgical management. Ophthalmologica. 2018. doi:10.1159/000488118
