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8 Surgical Management ofDiabetic Retinopathy
adequate staining is achieved upon injection, immediate aspiration follows. If
visualization is insufcient, the endo-illuminator should be withdrawn, allowing
the agent to dwell for 30–60 seconds before aspiration and washout. This
approach balances minimal toxicity with enhanced visualization.
3. Hyperbaric delivery: Diluting the dye with a 5% glucose solution (which is rela-
tively hyperbaric/higher density compared to BSS) allows the agent to settle
directly onto the posterior pole. This prevents unwanted diffusion throughout the
vitreous cavity and focuses the staining on the target tissue.
8.6.2 Tamponades
(1) Intraoperative Tamponades
Peruorocarbon liquid (PFCL)is a vital intraoperative tool for stabilizing the posterior pole and protecting the macula from mechanical traction. Acting as a “third
hand,” PFCL enables surgeons to resect peripheral vitreous and dissect proliferative
membranes with greater safety and efciency.Despite these advantages, novice surgeons should exercise caution when using PFCL for retinal attening. In cases
involving rigid, contracted retina, PFCL can become sequestered within retinal
folds or migrate into the subretinal space through occult micro-tears. Therefore,
PFCL should be reserved as a last resort if air/uid exchange fails to achieve adequate reattachment. During administration, a gentle injection technique is essential
to prevent “sh-egg” droplet formation, IOPspikes, or iatrogenic retinal damage.
Viscoelastic agents may also assist with adhesions, though their use should be
limited due to uncertain safety proles and difculty in detecting residual material
in the vitreous cavity.
(2) Postoperative Tamponades
For uncomplicated vitreous hemorrhage (VH) where the retina is at and laser photocoagulation is secure, balanced salt solution (BSS) may be used for primary tamponade, or ltered air for short-term support. In cases of moderate retinal
proliferation, provided the membranes are completely removedand retinal hemorrhage is minimal, inert gas is an appropriate tamponade choice (Fig.8.16).
Silicone oil is indicated for severe PDR with high vascular activity due to its
hemostatic properties and its role in preventing iris neovascularization by blocking
the anterior migration of VEGF.For elderly patients, oil removal is generally recommended at 3–6 months. Delayed removal often leads to advanced cataracts with
harder nuclei and poor pupillary dilation, complicating future surgery for novice
surgeons. In these challenging scenarios, the risk of serious complications like corneal endothelial decompensation is signicantly elevated.
8.6 Vital Dyes andIntraocular Tamponade Agents
183
a
b
Fig. 8.16 Management of severe PDR with TRD. (a) Preoperative fundus showing superotempo-
ral TRD (red dashed line) and tight posterior hyaloid adhesion on OCT (white box). Post-membrane
excision, residual retinal folds remained (red box). (b) Three weeks postoperatively, the folds
resolved spontaneously, and the retina is now fully attached (red dashed line). BCVA improved
from 0.02 to 0.6, with nearly normal macular anatomy
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8 Surgical Management ofDiabetic Retinopathy
8.7 How toGet Rid ofIntraoperative Dilemmas
8.7.1 Corneal Edema
Corneal edema is common in PDR patients during surgery. If it occurs early in the
procedure, it signicantly impairs intraocular visualization. The following measures can be taken to reduce the incidence and severity of corneal edema:
1. Limit Preoperative chemical exposure: Control the duration of povidone-iodine
contact with the conjunctival sac (ideally≤1min) to reduce epithelial toxicity.
2. Maintain epithelial hydration: Intraoperatively, apply viscoelastic sodium to
shield the corneal surface, or irrigatewith BSS to ensure the epithelium remains
adequately hydrated.
3. Optimize uid dynamics: Maintain a stable infusion pressure, ideally between
20–25 mmHg. Avoid premature PFCL injection or air/uid exchange, as sudden
IOPuctuations can trigger corneal decompensation.
4. If necessary, scrape off the edematous corneal epithelium with a blade.
8.7.2 Lens Opacity
Beyond avoiding iatrogenic trauma, utilizing valved trocars is essential to minimize
IOPuctuations. Ensure the infusion cannula is angled toward the center of the
vitreous cavity. This prevents localized turbulent owfrom directly impacting the
posterior lens surface. Although BSS contains glucose, a signicant gradient
between the infusion uid and the patient’s elevated systemic glucose levels can
trigger acute osmotic lens opacication. Therefore, preoperative blood glucose
must be stabilized within a therapeutic range.Avoid premature air-uid exchange or
PFCL injection, as these maneuvers can induce sudden IOP shifts that compromise
corneal and lens clarity.
Furthermore, combinedcataract surgery with PPVis not recommendedin PDR
cases. Combining these procedures acutely increases surgical complexity and elevates the risk of postoperative inammatory complications.
8.7.3 Pupillary Constriction
Due to diabetes-related reductions in iris elasticity, some PDR patients exhibit inadequate mydriasis or progressive intraoperative miosis, which can compromise the
visualization of surgical maneuvers. Fortunately, the integration of wide-angle
8.7 How toGet Rid ofIntraoperative Dilemmas
185
viewing systems has made this issue less limiting by providing a broader eld of
view despite a smaller pupillary aperture.
In patients with stable systemic blood pressure, intrameal epinephrine can be
administered to enhance pupillary dilation. A common clinical preparation involves
diluting 0.1% epinephrine in a 10-mL BSS-lled syringe (aspirating a volume
approximately equal to a small air bubble). Generally, the use of iris retractors is
discouraged in PDR cases, as the fragile, inelastic iris tissue is highly susceptible to
iatrogenic tears and hemorrhage.
8.7.4 Iatrogenic Retinal Tears
Iatrogenic retinal tears represent a signicant complication in PDR surgery, often
arising from a combination of complex factors. Despite the implementation of various surgical techniques, the manipulation required for proliferative membrane management may result in iatrogenic tears. While such incidents can occur during
surgery, focus remains on prevention through rened maneuvers.
In the event that an iatrogenic retinal tear is identied, the vitreous surrounding
the break should be resected thoroughly, and any adhering proliferative membranes
should be removed. When managed appropriately, these tears can be utilized effectively during the procedure as conduits for draining subretinal uid during air/uid
exchange. Following successful reattachment of the retina, laser photocoagulation
is employed to seal the tear. With timely and precise intervention, these events typically do not lead to severe long-term complications.
8.7.5 Intraoperative Bleeding
Intraoperative bleeding in PDR surgery can originate from multiple sources, including neovascularization, the optic disc, retinal vasculature, the iris, scleral ports, or
the choroid. As in conventional vitrectomy, the most critical preventive strategy is
the judicious adjustment and maintenance of infusion pressure.
Hemorrhage is most frequently encountered during the resection or delamination
of proliferative membranes with rm vascular adhesions (Fig.8.17). Once active
bleeding is identied, immediate intervention is mandatory. Due to the increased
blood viscosity characteristic of PDR patients, large-volume hemorrhage becomes
difcult to aspirate and can severely obscure the surgical eld, hindering further
maneuvers. The following techniques should be employed to achieve effective
hemostasis:
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8 Surgical Management ofDiabetic Retinopathy
ab
Fig. 8.17 Retinal bleeding during proliferative membrane resection. (a) Severe bleeding occurs
when resecting a proliferative membrane tightly adherent to the retina (blue arrow) with a vitrectome. (b) After aspirating the blood clot with a vitrectome, an active bleeding site is identied
(green arrow)
(1) Temporarily Increasing Infusion Pressure
The duration must be strictly controlled (≤3min) to avoid severely impairing retinal
perfusion. After bleeding is controlled, the infusion pressure can be gradually
reduced to the normal range in a stepwise manner.
(2) Intraocular Instrument Compression Hemostasis
Use the tip of a ute needle or vitrectomy cutter to gently press the bleeding site for
at least 1min. Avoid ineffective compression due to hand tremors.
(3) Timely Air/Fluid Exchange
Bleeding dissolves quickly in BSS, impairing surgical eld visibility. Air/uid
exchange can be performed to allow hemostatic manipulation under gas tamponade.
(4) Electrocoagulation
Precision is essential: the intensity should be controlled within a reasonable range
to avoid iatrogenic tears.
(5) Laser Photocoagulation
This is a safe and effective method that beginners should master. The tip of the laser
ber does not need to contact the bleeding site; the laser beam can accurately target
the bleeding point, using thermal effects to induce coagulation and hemostasis.
(6) “Luring the Snake Out of Its Hole”
To thoroughly address all bleeding sites intraoperatively, after initial hemostasis,
temporarily reduce the infusion pressure to 15–20mmHg and wait briey. Carefully
8.8 Postoperative Complications andtheManagement
observe for active bleeding; if detected, use laser photocoagulation for precise
sealing.
187
8.8 Postoperative Complications andtheManagement
Beyond the complications inherent to vitrectomy and intraocular tamponades, PDR
patients are predisposed to specic postoperative challenges.
8.8.1 Elevated Intraocular Pressure
Postoperative ocular hypertension can manifest in early or late stages. Management
should be guided by the severity of the IOP elevation and anterior segment ndings,
third of patients experience transient IOP elevation. Notably, corneal edema may
result in overestimated readings via non-contact tonometry (NCT); therefore, clinical symptoms such as headache and ocular pain must be assessed.Observation is
typically sufcient for IOP 30 mmHg, 1–2 types of topical hypotensive agents
should be initiated, with systemic medications added if necessary.If the elevation is
secondary to pupillary block, it often progresses rapidly. Management includes
immediate intensive anti-inammatory and mydriatic therapy, strict adherence to a
prone position, and prompt surgical intervention if conservative measures fail.
Delayed IOP elevation is frequently caused by silicone oil emulsication. In rare
instances, it may be secondary to neovascular glaucoma (NVG) or progressive retinal proliferation. Treatment must be tailored to the underlying etiology.
Middle-to-late postoperative IOP elevation is often caused by silicone oil emulsication; in rare cases, it is secondary to iris neovascularization or worsening retinal proliferation. Management should be tailored to the specic cause.
specically anterior chamber depth and inammatory status.Approximately one-
8.8.2 Uveal Reaction andInflammation
Signicant postoperative uveal reactions are common in PDR patients, driven by a
systemic pro-inammatory state and extensive intraoperative manipulation.
Manifestations include pupillary exudative membranes, keratic precipitates (KPs),
aqueous are, and cells. Compared to standard vitrectomy, PDR cases require intensied postoperative anti-inammatory regimens. If indicated, systemic corticosteroids may be administered under rigorous blood glucose monitoring. Cycloplegic
therapy is essential: atropine ointment is preferred during the initial postoperative
week, followed by a transition to tropicamide eye drops.
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8 Surgical Management ofDiabetic Retinopathy
8.8.3 Lens Opacity
onset cataracts are common and require experienced surgeons, with pre-operative
stabilization of retinal proliferation and mandatory post-operative monitoring for
macular edema and neovascularization.
8.8.4 Iris Neovascularization andSecondary Glaucoma
Neovascularization of the iris (NVI) typically manifests several weeks postopera-
posterior segment procedures (e.g., phaco-vitrectomy) (Fig.8.18).To mitigate the
risk of NVI, surgeons should prioritize the following strategies: (1)Ensure the judicious use of perioperative anti-VEGF agents and the administration of comprehensive, conuent PRP; (2) Minimize intraoperative manipulation of the anterior
segment to reduce the release of pro-angiogenic inammatory mediators; (3)Verify
that the PRP is sufciently extensive to eliminate retinal ischemia, which is the
primary driver of VEGF production.If the elevated IOPremains refractory despite
aggressive pharmacological intervention, a timely referral to a glaucoma specialist
is mandatory for the management of potential neovascular glaucoma (NVG).
If no iatrogenic damage occurs, post-inammatory lens opacity often resolves.Late-
tively. Key risk factors include aphakia, pseudophakia, and combined anterior-
8.8.5 Anterior Hyaloidal Fibrovascular Proliferation
Anterior hyaloidal brovascular proliferation (AHFP)is a distinct manifestation of
proliferative vitreoretinopathy (PVR) following PDR surgery, predominantly affecting young male patients with Type 1 diabetes. It is characterized by brovascular
Fig. 8.18 Postoperative
iris neovascularization.
Neovascularization of the
irisobserved one month
following phaco-
vitrectomyfor PDR
8.8 Postoperative Complications andtheManagement
189
membranes that originate from the peripheral retina and extend anteriorly toward
the ciliary epithelium, the posterior lens capsule, and the posterior iris surface.
Clinically, patients present with rapid, severe vision loss, accompanied by signicant anterior segment inammation and hyphema. Due to its aggressive nature,
AHFP is challenging to treat and carries a poor visual prognosis.
Prevention during the primary surgery is critical. Two key strategies are essential
to mitigate this risk: (1)Performing extensive, conuent PRP that reaches the posterior edge of the ora serrata; (2)Executing a thorough peripheral vitreous shaving
under scleral indentation to remove the scaffold for future proliferation.
8.8.6 Intraocular Fibrin Syndrome
This complication is rare but notoriously difcult to manage, often carrying a poor
visual prognosis. It is characterized by extensive intraocular brin exudation and
deposition, which can lead to pupillary membrane occlusion, tractional retinal
detachment, and secondary neovascularization (Fig.8.19).Key risk factors include:
(1) Combined anterior-posterior segment surgery (e.g., phaco-vitrectomy);
(2)Excessive or high-intensity laser photocoagulation, which triggers a massive
inammatory response.
8.8.7 Vitreous Hemorrhage
Early postoperative vitreous hemorrhage may arise from minor leakage from retinal
vessels, residual brovascular membranes left after surgery, or postoperative dispersion of residual blood from the peripheral vitreous into the vitreous cavity. Close
observation, mainly using B-scan ultrasonography, is recommended, and surgical
intervention is generally unnecessary in the short term. Some patients may benet
from repeat intravitreal anti-VEGF injection. If the hemorrhage does not clear after
1–2 months of observation, or if retinal detachment or elevated IOP develops, second surgerymay be performed, with caution to avoid complications associated with
a vitrectomizedeye. The bleeding source should be treated concurrently, and silicone oil tamponade should be considered when indicated.
Mid-to-late postoperative vitreous hemorrhage may result from recurrent retinal
brovascular proliferation. Neovascularization of the iris and angle may also lead to
vitreous hemorrhage. Management should be individualized according to the underlying cause.
190
cd
8 Surgical Management ofDiabetic Retinopathy
a b
Fig. 8.19 Postoperative brinoid syndrome following phaco-vitrectomy for PDR. (a) Baseline:
No retinal detachment on B-scan. (b) Combined phaco-vitrectomy and IOL implantation was performed due to dense cataract obscuring the fundus. (c) The retina remained at intraoperatively.
(d) Day 3 postoperative: Signicant vision loss. B-scan shows a classic funnel-shaped RD secondary to severe brinoid exudation
8.9 Summary
191
8.9 Summary
“Only a strategic protracted war is the sole path to nal victory.” The surgical management of advanced PDR is inherently complex, characterized by extended therapeutic timelines and signicant variability in procedural difculty. Achieving
successful outcomes necessitates comprehensive perioperative care and a high level
of technical prociency to navigate frequent and multifaceted intraoperative and
postoperative complications.
Novice surgeons should initially operate under the close supervision of senior mentors. It is essential to strictly adhere to surgical indications, prioritize clinical observation, and engage in continuous self-reection and systematic case reviews.
Independent management of severe PDR cases should only be undertaken after
accumulating substantial surgical experience and demonstrating consistent clinical
judgment.