26.3 Ocular Trauma Repair: Open Globe Management, Hyphema, Vitreous Loss & Endophthalmitis Protocol

Ocular Trauma Repair: Open Globe Management, Hyphema, Vitreous Loss & Endophthalmitis Protocol

Core Clinical Mandate: Ocular trauma represents an ophthalmic emergency where clinical decision-making within the first golden hour dictates lifelong visual prognosis. Ophthalmic medical technologists must master the standardized Birmingham Eye Trauma Terminology (BETT), strict zero-pressure open globe triage, sickle cell pharmacotherapeutic contraindications in hyphema, microsurgical management of intraoperative vitreous loss, and the landmark Endophthalmitis Vitrectomy Study (EVS) protocol.

The Birmingham Eye Trauma Terminology (BETT) Classification

Endorsed by the American Academy of Ophthalmology (AAO) and the International Society of Ocular Trauma, the Birmingham Eye Trauma Terminology (BETT) provides an unambiguous, comprehensive classification for mechanical ocular injuries based strictly on the status of the eyewall (defined as the rigid fibrous shell formed by the cornea and sclera).

BETT Mechanical Ocular Trauma Hierarchy:
[Mechanical Ocular Injury]
   ├── [CLOSED GLOBE] (Eyewall lacks full-thickness breach)
   │     ├── Contusion (Blunt impact; internal tissue damage without eyewall defect)
   │     └── Lamellar Laceration (Partial-thickness eyewall wound)
   └── [OPEN GLOBE] (Full-thickness eyewall breach)
         ├── RUPTURE (Blunt impact; acute IOP surge; INSIDE-OUT bursting at weak points)
         └── LACERATION (Sharp impact; OUTSIDE-IN cutting of eyewall)
               ├── Penetrating (Single entrance wound; no exit wound)
               ├── Intraocular Foreign Body / IOFB (Retained projectile inside globe)
               └── Perforating (Two full-thickness wounds: entrance AND exit from same object)

Rupture vs. Laceration: Pathophysiologic Distinctions

• Globe Rupture (Inside-Out Injury):
  • Mechanism: Caused by blunt impact from a non-incising, blunt object larger than the orbital rim (e.g., fist, baseball, steering wheel). The impact rapidly compresses the globe in the anteroposterior axis, generating an instantaneous, massive rise in intraocular pressure.
  • Burst Mechanics: The sclera bursts from the inside out at the anatomically thinnest and weakest points of the globe:
    1. Directly behind the rectus muscle insertions, where the sclera is thinnest (only 0.30 mm thick compared to 1.0 mm at the posterior pole).
    2. At the corneoscleral limbus.
    3. Along previous surgical incisions (prior PKP graft junctions, phacoemulsification wounds, radial keratotomy [RK] incisions).
  • Clinical Picture: Typically presents with extensive uveal and retinal prolapse, irregular wound edges, profound hypotony, and severe subconjunctival bullous chemosis (often 360°).
• Eyewall Laceration (Outside-In Injury):
  • Mechanism: Caused by a sharp, cutting, or high-velocity projectile object (e.g., knife, needle, metal shrapnel, glass). The object slices the eyewall from the outside in at the point of impact.
  • Penetrating Injury: Characterized by a single full-thickness entrance wound without an exit wound. The projectile may bounce out or remain retained.
  • Intraocular Foreign Body (IOFB): A penetrating wound where the mechanical missile remains retained within the eye.
  • Perforating Injury: Characterized by two full-thickness wounds—an entrance wound AND an exit wound—caused by the exact same through-and-through projectile (e.g., high-velocity metallic nail or bullet).

Emergency Triage, Rigid Shielding & Prohibited Maneuvers

When evaluating any patient with periocular trauma, the primary mandate of the ophthalmic technologist is to suspect an open globe until proven otherwise.

Clinical Red Flags for Open Globe

• Profound, sudden reduction in visual acuity.
• Peaked or eccentric pupil: The pupil peaks like a teardrop pointing directly toward the site of the corneal or limbal wound, caused by iris tissue plugging the internal defect.
• Extruded intraocular contents: Dark, brownish uveal tissue (iris or ciliary body), gelatinous vitreous strands, or lens material visible at the wound margin or beneath the conjunctiva.
• Markedly shallow or completely flat anterior chamber (or abnormally deep AC compared to fellow eye, indicating posterior rupture).
• Profound hypotony (IOP < 5 mmHg); however, tonometry should never be performed.
• Massive, bullous, 360° subconjunctival hemorrhage (indicative of an occult posterior scleral rupture beneath rectus muscles).
• Positive Seidel test (dilution and streaming of concentrated fluorescein by leaking aqueous humor under cobalt blue light; Clinical Note: Seidel testing should be avoided if obvious gross rupture is present to avoid globe manipulation).

Immediate Emergency Triage Protocol: DO NO HARM

Once an open globe is suspected, the physical examination must be immediately halted to prevent iatrogenic globe herniation:

Emergency Open Globe Immediate Action Sequence:
1. STOP EXAMINATION IMMEDIATELY
2. APPLY RIGID FOX EYE SHIELD (Resting strictly on orbital bones)
3. ABSOLUTELY NO PATCHES, NO COTTON PADS, NO GLOBE PRESSURE
4. ENFORCE STRICT NPO (Nothing by Mouth)
5. ADMINISTER IV ANTIEMETICS (Ondansetron 4 mg IV stat)
6. ADMINISTER PAIN CONTROL & TETANUS PROPHYLAXIS
7. INITIATE SYSTEMIC BROAD-SPECTRUM ANTIBIOTICS
8. ORDER NON-CONTRAST 1-MM THIN-CUT ORBITAL CT (MRI ABSOLUTELY CONTRAINDICATED)

• 1. Rigid Fox Shield Placement: A perforated aluminum or rigid plastic Fox eye shield must be taped securely over the eye, resting its edges strictly on the bony orbital margins (the frontal bone superiorly and zygomatic cheek inferiorly).
  • CRITICAL WARNING: NEVER place an eye patch, gauze pad, or cotton dressing underneath the shield! Any soft dressing placed beneath the shield transfers direct mechanical compression onto the globe whenever the patient blinks, squints, or turns their head, instantly extruding the uvea, lens, and retina through the wound.
• 2. Zero Globe Manipulation: Never attempt to invert the eyelids. Do NOT perform tonometry (Goldmann, Tono-Pen, or iCare). Do NOT perform scleral depression or contact B-scan ultrasound. Do NOT instill topical diagnostic drops (fluorescein, cycloplegics, anesthetics) or antibiotic ointments. Ointment vehicles (petrolatum/lanolin) and preservatives (benzalkonium chloride) enter the anterior chamber and cause catastrophic toxic endothelial destruction and sterile endophthalmitis.
• 3. Antiemetics & Valsalva Prevention: Retching, coughing, or vomiting spikes central venous pressure and intraocular pressure above 60 mmHg, which can cause immediate total globe evisceration through the wound. Administer ondansetron 4 mg IV immediately to eliminate nausea.
• 4. Diagnostic Imaging Protocols:
  • Non-Contrast Thin-Cut (1.0 mm) Computed Tomography (CT) of the Orbits: The gold standard imaging modality. Evaluates globe contour, demonstrates scleral collapse, localizes intraocular foreign bodies, and identifies orbital fractures.
  • MRI ABSOLUTELY CONTRAINDICATED: If a metallic intraocular foreign body is suspected (e.g., hammering, grinding, metal-on-metal striking), Magnetic Resonance Imaging (MRI) is strictly forbidden. The strong magnetic field induces high ferromagnetic torque, causing the metallic projectile to rotate, migrate, and shred intraocular tissues, converting a treatable wound into irreversible blindness.

Surgical Principles of Open Globe Primary Closure

• Anesthesia Protocol: General anesthesia is mandatory. Succinylcholine (depolarizing neuromuscular blocker) is strictly contraindicated because it induces sustained contracture of extraocular muscles, elevating IOP by 10 to 20 mmHg and extruding intraocular contents during induction. Rapid sequence induction utilizes non-depolarizing agents (e.g., rocuronium or vecuronium).
• Watertight Wound Closure:
  • Corneal Lacerations: Closed with 10-0 nylon interrupted sutures. The first "anchor" suture is placed precisely at the corneoscleral limbus to restore anatomical orientation, followed by sequential bisecting sutures working from the periphery toward the visual axis. Sutures are placed at 90% stromal depth with knots buried away from the visual axis.
  • Scleral Ruptures: Conjunctival peritomy is performed to expose the scleral tear. Scleral defects are closed using 8-0 or 9-0 nylon or polyester sutures placed in an interrupted fashion, working from anterior to posterior ("close as you go") to prevent extrusion of posterior uvea and retina.
  • Prolapsed Uveal Tissue Management: Iris tissue prolapsed for less than 24 hours without gross purulent contamination is gently irrigated with antibiotic-balanced salt solution and reposited into the anterior chamber using a cyclodialysis spatula. Macerated, depigmented, or necrotic tissue prolapsed for longer than 24 hours is excised to reduce the risk of endophthalmitis and sympathetic ophthalmia (a devastating autoimmune bilateral granulomatous panuveitis triggered by exposure of sequestered uveoretinal antigens to systemic lymphatics).

Traumatic Hyphema & Sickle Cell Hemoglobinopathy Hazards

A hyphema is the accumulation of red blood cells in the anterior chamber, typically resulting from blunt force trauma that compresses the globe, stretching the iris and ciliary body and tearing the anterior ciliary arterial circle or iris root vessels (angle recession).

Hyphema Clinical Grading Scale

Hyphema Severity Grading:
[Microscopic] ──► Erythrocytes suspended in aqueous; no layered clot
[Grade I]     ──► Layered blood occupying < 33% (less than 1/3) of AC volume
[Grade II]    ──► Layered blood occupying 33% to 50% (1/3 to 1/2) of AC volume
[Grade III]   ──► Layered blood occupying 50% to < 100% (1/2 to near-total) of AC volume
[Grade IV]    ──► 100% Total AC filling ('8-Ball' / Black Hyphema; dark purple/black clot)

The Secondary Hemorrhage Window (Re-bleed Kinetics)

• Incidence and Timing: Occurs in approximately 10% to 30% of traumatic hyphema cases. Secondary re-bleeding classically peaks between post-injury day 3 and day 5.
• Pathophysiology: Following the initial injury, a stable platelet-fibrin clot forms over the sheared vessel wall. Between days 3 and 5, physiological fibrinolysis and clot retraction naturally occur. If clot dissolution occurs before the injured vascular endothelium has fully regenerated, massive secondary hemorrhage erupts into the anterior chamber.
• Clinical Consequences: Re-bleeds are associated with a dramatically higher incidence of intractable secondary glaucoma, permanent corneal endothelial blood staining (erythrocytic breakdown products and hemosiderin penetrate Descemet's membrane, turning the cornea opaque rust-brown), and secondary optic atrophy.
• Medical Regimen: Strict bed rest with the head of the bed elevated 30° to 45° (promotes inferior erythrocyte pooling, clearing the central visual axis and superior trabecular meshwork), a rigid Fox shield, topical cycloplegics (atropine 1% or cyclopentolate 1% to immobilize the iris/ciliary body), and topical corticosteroids (prednisolone acetate 1%) to suppress inflammation. Aspirin, ibuprofen, and NSAIDs are strictly prohibited due to antiplatelet activity.

Sickle Cell Trait and Disease (HbSS, HbSC, HbS-beta Thal) Mandates

In all African American, Mediterranean, and Hispanic patients presenting with hyphema, immediate screening for sickle hemoglobinopathies (Sickledex / hemoglobin electrophoresis) is mandatory.

Sickle Cell Hyphema Pathophysiological Cascade:
[AC Hypoxia & Acidosis] ──► [Erythrocytes Sickle into Rigid Crescents]
──► [Rigid Sickled Cells Cannot Pass Trabecular Meshwork Pores (~2-10 µm)]
──► [Severe Trabecular Outflow Blockade] ──► [RAPID SEVERE IOP SPIKE]
──► [Compromised Perfusion to Optic Nerve / Retina] ──► [CRAO at IOP > 24 mmHg!]

• The Fragile Perfusion Threshold: In non-sickle patients, the optic nerve can tolerate intraocular pressures of 30 to 35 mmHg for several days without permanent glaucomatous cupping or ischemic infarction. In striking contrast, patients with sickle cell hemoglobinopathies develop Central Retinal Artery Occlusion (CRAO) and total optic nerve infarction at IOPs as low as 24 mmHg sustained for only 24 hours!
• Target IOP Standard: In sickle cell patients, intraocular pressure must be aggressively maintained strictly below 24 mmHg at all times.
• STRICT PHARMACOTHERAPEUTIC CONTRAINDICATIONS IN SICKLE HYPHEMA:
  1. Carbonic Anhydrase Inhibitors (CAIs) STRICTLY PROHIBITED:
     • Agents: Oral acetazolamide (Diamox), methazolamide, and topical dorzolamide (Trusopt) or brinzolamide (Azopt).
     • Mechanism of Toxicity: Systemic and topical CAIs induce systemic and aqueous metabolic acidosis. Furthermore, acetazolamide increases the osmolality of anterior chamber aqueous humor. Lowering the pH (acidosis) and increasing osmolality dramatically accelerates erythrocyte sickling, converting round flexible red cells into rigid, sickle-shaped plugs that permanently obstruct the trabecular meshwork, causing acute ocular hypertension.
  2. Osmotic Hyperosmolar Agents (Mannitol) Caution:
     • Intravenous mannitol induces systemic dehydration and hemoconcentration, which promotes red cell sickling and vaso-occlusive crisis. Used only as a brief last resort.
  3. Alpha-2 Agonists (Apraclonidine, Brimonidine) Caution:
     • Induce anterior segment microvascular vasoconstriction, worsening anterior chamber hypoxia and accelerating sickling.
• Safe First-Line Glaucoma Therapy in Sickle Hyphema: Topical beta-blockers (e.g., timolol 0.5%) are the safest primary agents.

Intraoperative Vitreous Loss in Anterior Segment Surgery

During anterior segment procedures—most notably phacoemulsification cataract surgery—rupture of the posterior lens capsule (posterior capsular rupture [PCR]) or large zonular dialysis breaches the anterior hyaloid face, allowing vitreous gel to prolapse into the anterior chamber, the paracenteses, and the main surgical incision.

Sequelae of Unmanaged Vitreous Incarceration

If vitreous is allowed to remain incarcerated in surgical wounds, severe complications develop:

• Vitreous Wick Syndrome: Vitreous fibers extending through the wound to the external ocular surface act as a wick, drawing ocular surface bacteria directly into the eye, precipitating infectious endophthalmitis.
• Cystoid Macular Edema (CME / Irvine-Gass Syndrome): Chronic anterior-posterior traction on the vitreous base transmits mechanical stress to the macular capillary bed, causing chronic vascular leakage and CME.
• Retinal Detachment: Vitreous traction on the peripheral retina induces giant retinal tears or horseshoe tears.
• Pupillary Distortion & Secondary Glaucoma: An updrawn, peaked, or eccentric pupil with secondary angle-closure glaucoma.

Microsurgical Management: The Anterior Vitrectomy Protocol

1. Do NOT Abruptly Withdraw the Phacoemulsification Handpiece:
   • The immediate reflex of an inexperienced surgeon is to pull the phaco probe out of the eye. This causes immediate anterior chamber collapse, allowing the high pressure of the posterior segment to drive massive amounts of vitreous and retained lens fragments forward into the anterior chamber.
   • Correct Action: Maintain the probe in the eye, turn aspiration off, and inject a dispersive ophthalmic viscosurgical device (OVD) (e.g., Viscoat) through the side-port paracentesis to tamponade the capsular defect and push the vitreous face posteriorly before withdrawing the probe.
2. Triamcinolone Acetonide Visualization:
   • Vitreous gel is 99% water and optically transparent. Attempting to cut clear vitreous blindly leads to incomplete removal or aggressive tugging on the retina.
   • Instill 0.1 to 0.2 mL of preservative-free triamcinolone acetonide (Triesence) into the anterior chamber. The white corticosteroid granules adhere selectively to the collagen fibrils of the vitreous, turning invisible vitreous strands into bright white, well-defined cords.
3. Bimanual Anterior Vitrectomy Fluidic Parameters:
   • Separate Infusion and Aspiration: Coaxial vitrectomy (infusion and cutting on the same handpiece) is obsolete because the co-axial infusion jet pushes vitreous into the cutter port while hydrating and expanding the vitreous volume. Modern anterior vitrectomy utilizes a bimanual technique: a smooth irrigation cannula is placed through one paracentesis, and the vitrectomy cutter is entered through a separate paracentesis or a pars plana sclerotomy.
   • High Cut Rate: Set to the maximum system speed (3,000 to 5,000+ cuts/min). High cut rates reduce bite volume and prevent transmission of tractional tugging to the peripheral retina.
   • Low Vacuum / Low Flow Rate: Vacuum is kept low (100 to 150 mmHg) with minimal aspiration flow rate (15 to 20 mL/min) to prevent sudden surges.
   • Positioning the Cutter: The cutter port is positioned in the anterior chamber pointing posteriorly or through the capsular defect, cutting vitreous cleanly until the anterior chamber and pupil are completely free of white triamcinolone-stained strands.

Endophthalmitis Vitrectomy Study (EVS) Protocol

Acute post-operative infectious endophthalmitis is a catastrophic intraocular infection occurring within 6 weeks of intraocular surgery (typically 2 to 7 days post-op), characterized by sudden severe visual loss, extreme ocular pain, hypopyon, dense vitritis, and loss of red reflex.

The Landmark EVS Trial Paradigm

The Endophthalmitis Vitrectomy Study (EVS) was a landmark multicenter randomized controlled clinical trial that evaluated 420 patients with acute post-cataract endophthalmitis to determine whether immediate 3-port Pars Plana Vitrectomy (PPV) or Vitreous Tap-and-Inject yielded superior visual outcomes.

EVS Clinical Treatment Threshold:
[Acute Post-Cataract Endophthalmitis within 6 Weeks]
   ├── VISUAL ACUITY = LIGHT PERCEPTION (LP) ONLY
   │     └── MANDATORY IMMEDIATE PARS PLANA VITRECTOMY (PPV) + Intravitreal Antibiotics
   │           (Achieves 3-fold increase in 20/40 visual recovery: 33% vs 11%)
   └── VISUAL ACUITY = HAND MOTION (HM) OR BETTER (HM, CF, Snellen)
         └── IMMEDIATE VITREOUS TAP-AND-INJECT (or PPV)
               (Visual outcomes are statistically identical: 74% achieve ≥20/100)

The EVS Visual Acuity Cutoff Rule

• Light Perception (LP) Only Vision:
  • In patients whose visual acuity has deteriorated to Light Perception only, immediate 3-port Pars Plana Vitrectomy (PPV) combined with intravitreal antibiotics is mandatory.
  • Clinical Evidence: Patients with LP vision who underwent immediate vitrectomy had a three-fold increase in the frequency of achieving 20/40 or better visual acuity (33% vs. 11%), an almost two-fold increase in achieving 20/100 or better (56% vs. 30%), and a 50% reduction in severe visual loss (<5/200) compared to tap-and-inject.
  • Mechanistic Rationale: Vitrectomy physically debulks the overwhelming bacterial load, removes destructive bacterial endo- and exotoxins, clears inflammatory proteolytic enzymes, eliminates vitreous scaffold membranes, and restores clear ocular media.
• Hand Motion (HM) or Better Vision:
  • In patients presenting with Hand Motion (HM), Counting Fingers (CF), or better vision, there was no statistically significant difference in final visual acuity or media clarity between immediate PPV and immediate bedside Vitreous Tap-and-Inject.
  • Therefore, eyes with HM or better are safely managed with immediate Vitreous Tap-and-Inject, avoiding the operating room delays and surgical risks of urgent vitrectomy.

The Vitreous Tap-and-Inject Protocol

• Vitreous Biopsy / Tap:
  • Performed under sterile conditions with a 5% povidone-iodine prep. A 23-gauge or 25-gauge needle attached to a 1 mL tuberculin syringe is inserted through the pars plana (3.5 mm posterior to the limbus in pseudophakic eyes, directed toward the mid-vitreous cavity).
  • 0.1 to 0.2 mL of pure vitreous is aspirated. If vitreous is too viscous or organized to aspirate with a needle ("dry tap"), an automated small-gauge vitreous biopsy cutter must be utilized. Anterior chamber taps (0.1 mL aqueous) have a much lower culture yield and cannot substitute for a vitreous sample.
  • Specimens are immediately inoculated onto blood agar, chocolate agar, Sabouraud dextrose agar, thioglycollate broth, and prepared on glass slides for urgent Gram stain and Giemsa stain.
• Intravitreal Empirical Broad-Spectrum Antibiotic Regimen:
  • Antibiotics are injected sequentially through the pars plana using separate 30-gauge needles, directed toward the mid-vitreous cavity:
  1. Vancomycin: 1.0 mg in 0.1 mL
     • Provides comprehensive bactericidal coverage against Gram-positive bacteria (which account for >90% of post-cataract endophthalmitis isolates), including Staphylococcus epidermidis, Staphylococcus aureus (including MRSA), and Streptococcus species.
  2. Ceftazidime: 2.25 mg in 0.1 mL
     • Provides potent bactericidal coverage against Gram-negative bacteria (including Pseudomonas aeruginosa, Proteus, and Enterobacter species).
     • Alternative for Severe Cephalosporin Allergy: Amikacin 0.4 mg in 0.1 mL (an aminoglycoside). Warning: Amikacin carries a known risk of irreversible macular infarction and retinal arteriolar necrosis if injected rapidly or inappropriately dosed.
  3. Adjunctive Intravitreal Dexamethasone: 0.4 mg in 0.1 mL
     • Administered to quell the host inflammatory response and prevent bystander photoreceptor damage.