Which surgical exposure is listed as a mechanism of iatrogenic macular injury?

Shear stress during membrane peeling Mechanical traction, instrument-induced trauma, excessive tissue manipulation, dye-related toxicity and shear stress during membrane peeling can all injure the delicate macula.

Prolonged topical anaesthetic exposure

Raised episcleral venous pressure after surgery

Sudden decompression of the anterior chamber

When may an iatrogenic full-thickness macular hole appear after vitreoretinal surgery?

Days, weeks or even months postoperatively Secondary macular holes may appear days, weeks or even months after surgery, attributed to excessive peeling traction, foveal tissue weakening, residual tangential traction and postoperative cystoid change.

Only during the operation itself

Only after silicone oil removal

Which OCT picture characterises dissociated optic nerve fibre layer after ILM peeling?

Arcuate depressions and inner dimpling with intact outer retina DONFL shows small arcuate depressions and inner retinal dimpling with preservation of the outer retinal layers, and in most cases visual acuity is unaffected.

Full-thickness foveal dehiscence with cystic edges

Subretinal fluid tracking beneath the fovea

Hyperreflective deposits at the pigment epithelium

Which iatrogenic macular defect is most likely to cause significant visual loss?

A full-thickness macular hole involving the fovea Significant impact is more likely with foveal involvement, full-thickness macular holes, extensive retinal trauma and outer retinal disruption, producing reduced acuity, metamorphopsia and central scotoma.

Dissociated optic nerve fibre layer appearance

A small inner retinal dimple outside the fovea

Peripheral macular contour irregularity

Which benefits make internal limiting membrane peeling a cornerstone of macular surgery?

Reduced epiretinal membrane recurrence and better hole closure ILM peeling reduces recurrence of epiretinal membranes and improves macular hole closure rates, although it also introduces mechanical stress such as Muller cell injury and retinal dimpling.

Lower intraocular pressure and faster corneal healing

Reduced postoperative inflammation and cataract risk

Shorter operating time and less need for tamponade

Which vital dye has historically raised the greatest concern about retinal toxicity?

Indocyanine green Brilliant Blue G, Trypan Blue and indocyanine green are all used for staining, but ICG has historically raised the greatest concerns regarding retinal toxicity.

Which features make highly myopic eyes vulnerable to iatrogenic macular injury during peeling?

Thin retina, foveoschisis and posterior staphyloma Highly myopic eyes often show a thin retina, foveoschisis and posterior staphyloma, and these structural changes increase vulnerability during peeling procedures.

Dense vitreous with strong foveal adhesion

Thickened choroid with hyperpermeable vessels

Pigment epithelial hypertrophy and drusen

Why is OCT central to detecting iatrogenic macular defects after vitreoretinal surgery?

Many such defects are invisible on clinical examination alone Many iatrogenic defects cannot be seen on clinical examination; OCT reveals inner retinal dimples, focal thinning, lamellar defects, full-thickness holes and layer disruption, and serial imaging tracks progression.

It measures retinal function rather than structure

It replaces the need for postoperative examination

It shows dye leakage from injured retinal capillaries

Which management approach suits dissociated optic nerve fibre layer and stable lamellar defects?

Observation without further intervention Observation is appropriate for DONFL, small inner retinal abnormalities and stable lamellar defects; surgery is reserved for progressive lamellar holes, full-thickness holes and symptomatic tractional defects.

Immediate repeat vitrectomy with gas tamponade

An internal limiting membrane flap procedure

A course of intravitreal anti-VEGF injections

Iatrogenic Macular Defects During Vitreoretinal Surgery

Modern vitreoretinal surgery has achieved remarkable success in the treatment of macular holes, epiretinal membranes, retinal detachments, diabetic tractional disease, and various complex retinal disorders.

Advances in instrumentation, visualization systems, and surgical techniques have significantly improved both anatomical and functional outcomes.

Despite these advances, vitreoretinal surgery is not without risks. One of the less common but potentially vision-threatening complications is the development of iatrogenic macular defects—retinal injuries occurring as an unintended consequence of surgical manipulation.

These defects may range from small inner retinal trauma to full-thickness macular holes and can adversely affect postoperative visual outcomes. Because they are relatively uncommon and often underrecognized, understanding their causes, risk factors, prevention, and management remains essential for retina specialists.

For vitreoretinal surgeons, awareness of iatrogenic macular defects is particularly important as surgical complexity continues to increase.

What Are Iatrogenic Macular Defects?

Iatrogenic macular defects are structural retinal abnormalities that develop during or shortly after vitreoretinal surgery as a direct result of surgical intervention.

They may involve:

Inner retinal defects
Dissociated retinal tissue changes
Foveal trauma
Lamellar macular holes
Full-thickness macular holes
Retinal thinning at manipulation sites

The severity ranges from clinically insignificant OCT findings to visually significant foveal damage.

👉 Not every postoperative macular abnormality represents disease progression; some may be procedure-related.

Why Do Iatrogenic Macular Defects Occur?

The macula is one of the most delicate structures in the eye.

Several surgical maneuvers may expose the retina to:

Mechanical traction
Instrument-induced trauma
Excessive tissue manipulation
Dye-related toxicity
Shear stress during membrane peeling

Even technically successful surgery can occasionally result in microscopic retinal injury.

Test your knowledge 10 questions from this article

Common Types of Iatrogenic Macular Defects

1. Iatrogenic Full-Thickness Macular Hole

Although uncommon, a full-thickness macular hole may develop after vitreoretinal surgery performed for unrelated conditions.

Associated Procedures

Epiretinal membrane surgery
Retinal detachment repair
Diabetic vitrectomy
Vitreomacular traction surgery

Proposed Mechanisms

Excessive traction during membrane peeling
Foveal tissue weakening
Residual tangential traction
Postoperative cystoid changes

👉 Secondary macular holes may appear days, weeks, or even months after surgery.

2. Inner Retinal Defects

These subtle abnormalities are increasingly recognized with high-resolution OCT.

Characteristics include:

Localized retinal dimples
Focal thinning
Irregular inner retinal contour

They often occur following:

Internal limiting membrane (ILM) peeling
Extensive membrane dissection

Most are asymptomatic but may reflect microscopic surgical trauma.

3. Dissociated Optic Nerve Fiber Layer (DONFL)

DONFL is a characteristic postoperative finding after ILM peeling.

OCT Appearance

Small arcuate depressions
Inner retinal dimpling
Preservation of outer retinal layers

Clinical Significance

In most cases:

Visual acuity remains unaffected
No additional treatment is required

Although not considered a true complication by many surgeons, DONFL represents a form of surgically induced retinal alteration.

4. Iatrogenic Lamellar Macular Holes

Partial-thickness defects may occur when excessive traction is applied to fragile retinal tissue.

Risk factors include:

Thin foveal tissue
Pre-existing macular pathology
Aggressive membrane peeling

Lamellar defects may remain stable or progress over time.

Surgical Factors That Increase Risk

1. Internal Limiting Membrane Peeling

ILM peeling has become a cornerstone of modern macular surgery.

Benefits include:

Reduced recurrence of epiretinal membranes
Improved macular hole closure rates

However, ILM peeling also introduces mechanical stress.

Potential consequences include:

Müller cell injury
Inner retinal trauma
Retinal dimpling

👉 The therapeutic benefits of ILM peeling generally outweigh its risks, but careful technique remains essential.

2. Epiretinal Membrane Dissection

ERM removal may require significant tractional force.

Risk increases when:

Membranes are densely adherent
Visualization is poor
Multiple grasping attempts are required

Excessive traction can result in focal retinal injury.

3. Forceps-Induced Trauma

Microforceps provide excellent control but can occasionally damage retinal tissue.

Potential injuries include:

Direct retinal indentation
Focal retinal tears
Inner retinal defects

Modern small-gauge instrumentation has reduced these risks considerably.

4. Dye-Assisted Surgery

Vital dyes improve visualization of transparent tissues.

Common dyes include:

Brilliant Blue G
Trypan Blue
Indocyanine Green (ICG)

Although generally safe, concerns remain regarding:

Retinal toxicity
Phototoxicity
Dose-dependent cellular injury

👉 ICG has historically raised the greatest concerns regarding retinal toxicity.

5. Excessive Mechanical Manipulation

Repeated peeling attempts and prolonged surgery may increase cumulative retinal stress.

Factors include:

Multiple membrane layers
Difficult surgical planes
Poor staining
Limited visibility

The duration and complexity of surgery often correlate with injury risk.

Patient-Related Risk Factors

Certain retinal characteristics increase susceptibility to surgical injury.

High Myopia

Highly myopic eyes often exhibit:

Thin retina
Foveoschisis
Posterior staphyloma

These structural changes increase vulnerability during peeling procedures.

Pre-Existing Macular Disease

Eyes with:

Chronic epiretinal membranes
Macular holes
Cystoid macular edema
Retinal atrophy

may possess weakened retinal architecture that is more susceptible to iatrogenic damage.

Advanced Age

Age-related retinal thinning and reduced tissue elasticity may contribute to increased fragility during surgery.

OCT: The Key to Detection

Many iatrogenic macular defects are invisible on clinical examination alone.

OCT Findings May Include

Inner retinal dimples
Focal retinal thinning
Lamellar defects
Full-thickness holes
Disruption of retinal layers

Serial imaging is particularly useful for monitoring progression and assessing functional significance.

👉 OCT has dramatically improved recognition of subtle postoperative retinal changes.

Clinical Impact on Vision

The visual consequences depend on the location and severity of the defect.

Minimal Impact

Often seen with:

DONFL
Small inner retinal defects
Peripheral macular changes

Significant Impact

More likely with:

Foveal involvement
Full-thickness macular holes
Extensive retinal trauma
Outer retinal disruption

Visual symptoms may include:

Reduced acuity
Metamorphopsia
Central scotoma
Reading difficulties

Prevention Strategies

Preventing iatrogenic macular defects begins with meticulous surgical technique.

Key Preventive Measures

Careful ILM Peeling

Avoid excessive traction
Use gentle peeling movements
Maintain proper tissue planes

Optimal Visualization

Adequate staining
High-quality imaging systems
Appropriate illumination

Minimize Retinal Grasping

Reduce repeated forceps contact
Use controlled movements

Patient Selection

Recognize high-risk eyes before surgery.

👉 Prevention is often more effective than managing established postoperative defects.

Management of Iatrogenic Macular Defects

Treatment depends on defect severity.

Observation

Appropriate for:

DONFL
Small inner retinal abnormalities
Stable lamellar defects

Surgical Intervention

May be required for:

Progressive lamellar holes
Full-thickness macular holes
Symptomatic tractional defects

Repeat vitrectomy, ILM flap techniques, and gas tamponade may be considered when necessary.

Future Perspectives

Technological advances continue to improve surgical safety.

Emerging innovations include:

Intraoperative OCT
Robotic-assisted vitreoretinal surgery
Improved tissue visualization systems
Safer staining agents
Advanced retinal instrumentation

These developments may further reduce the incidence of surgically induced macular injury.

References

Pichi F, et al. “Retinal complications of internal limiting membrane peeling.” Retina. 2014.
Tadayoni R, et al. “Dissociated optic nerve fiber layer appearance after internal limiting membrane peeling.” Ophthalmology. 2001.
Steel DHW, Lotery AJ. “Retinal surface abnormalities after macular surgery.” Eye (Lond). 2013.
Spaide RF. “Dissociated optic nerve fiber layer appearance and inner retinal dimpling after ILM peeling.” Retina. 2012.
Shimada H, et al. “Secondary macular holes after vitrectomy.” Am J Ophthalmol. 2006.
Haritoglou C, et al. “Indocyanine green-assisted peeling of the internal limiting membrane.” Am J Ophthalmol. 2003.

Test yourself

A few questions straight from this article.

1 / 10 0 correct

How are iatrogenic macular defects during vitreoretinal surgery defined?
They are structural retinal abnormalities developing during or shortly after vitreoretinal surgery as a direct result of surgical intervention, ranging from subtle OCT findings to visually significant foveal damage.
Which surgical exposure is listed as a mechanism of iatrogenic macular injury?
Mechanical traction, instrument-induced trauma, excessive tissue manipulation, dye-related toxicity and shear stress during membrane peeling can all injure the delicate macula.
When may an iatrogenic full-thickness macular hole appear after vitreoretinal surgery?
Secondary macular holes may appear days, weeks or even months after surgery, attributed to excessive peeling traction, foveal tissue weakening, residual tangential traction and postoperative cystoid change.
Which OCT picture characterises dissociated optic nerve fibre layer after ILM peeling?
DONFL shows small arcuate depressions and inner retinal dimpling with preservation of the outer retinal layers, and in most cases visual acuity is unaffected.
Which iatrogenic macular defect is most likely to cause significant visual loss?
Significant impact is more likely with foveal involvement, full-thickness macular holes, extensive retinal trauma and outer retinal disruption, producing reduced acuity, metamorphopsia and central scotoma.
Which benefits make internal limiting membrane peeling a cornerstone of macular surgery?
ILM peeling reduces recurrence of epiretinal membranes and improves macular hole closure rates, although it also introduces mechanical stress such as Muller cell injury and retinal dimpling.
Which vital dye has historically raised the greatest concern about retinal toxicity?
Brilliant Blue G, Trypan Blue and indocyanine green are all used for staining, but ICG has historically raised the greatest concerns regarding retinal toxicity.
Which features make highly myopic eyes vulnerable to iatrogenic macular injury during peeling?
Highly myopic eyes often show a thin retina, foveoschisis and posterior staphyloma, and these structural changes increase vulnerability during peeling procedures.
Why is OCT central to detecting iatrogenic macular defects after vitreoretinal surgery?
Many iatrogenic defects cannot be seen on clinical examination; OCT reveals inner retinal dimples, focal thinning, lamellar defects, full-thickness holes and layer disruption, and serial imaging tracks progression.
Which management approach suits dissociated optic nerve fibre layer and stable lamellar defects?
Observation is appropriate for DONFL, small inner retinal abnormalities and stable lamellar defects; surgery is reserved for progressive lamellar holes, full-thickness holes and symptomatic tractional defects.