Intraocular Foreign Bodies (IOFB)

From EyeWiki

History & Ophthalmic Examination:
-Attention to mechanism of injury (e.g., knife wound, explosive device, shotgun blast) should be obtained
-Triage other life threatening injuries prior to ophthalmic injury
-Complete ophthalmic exam except applanation tonometry when a globe rupture is evident or suspected

• Features of the ophthalmic exam that may be predictive of long-term visual acuity using the "OCULAR TRAUMA SCORE" INCLUDE:
  -Presenting visual acuity
  -The presence or absence of endophthalmitis
  -Globe rupure
  -Perforating injury
  -Retinal detachment
  -Afferent pupillary defect

• When an IOFB is observed clinically, exam features that may be predictive of poor visual outcomes include:
  -Visual acuity
  -An afferent pupillary defect
  -Hyphema
  -Vitreous hemorrhage (presence of VH is strong risk factor for PVR)
  -Uveal prolapse
  -Retinal detachment

IMAGING:
-CT of the orbits without contrast is the test of choice in suspected or clinically evident globe rupture
-When an IOFB is found on CT scan, attention should be paid to its size, shape, location, and material if possible (e.g., metallic, wood, stone, vegetable matter)
-Helical CT was found to confer several advantages in the preoperative assessment of pts with IOFBs
-Specifically, helical CT was associated with a shorter acquisition time with reduced motion artifact, decreased radiation exposure, and the ability to obtain reconstructed sagittal and coronal views for localization of an IOFB. Helical CT has been demonstrated to be more sensitive.
-Thin cut axial sections with 0.625-1.25mm slices are preferable for smaller IOFBs
-Do not do B-scan ultrasonagraphy if suspect globe rupture
-UBM for occult FB in the posterior iris or CB region

MANAGEMENT:
-Give oral levofloxacin (500mg) or moxifloxacin (400mg) preop and for 7-10 days following open globe repair
-Advantages to immediate IOFB removal: decrease in risk of endophthalmitis, decrease in rate of PVR, and a single procedure under anesthesia.

PPV TECHNIQUE:
-Standard 20g or 23g PPV setup
-Send vitreous for STAT gram stain & culture (therefore decide to inject intravitreal abx if gram stain is positive; otherwise if there is no clinical evidence of endophthalmitis, do not need to inject abx)
-Send IOFB for culture
-Removal of cortical vitreous
-The presence or absence of a PVD is assessed and created if necessary (use Kenalog)
-After a PVD has been created, the vitreous adhesions surrounding the IOFB are cut circumferentially to ensure tha thte IOFB is not attached to the vitreous base and any adhesions or fibrosis.

-Consider placing PFCL to protect the macula during removal of the IOFB

STRATEGIES FOR IOFB EXTRACTION:
<1.0mm, magnetic = magnet or vitrector
1-3mm, stone = Basket forceps
3-5mm, glass = IOFB diamond-coated forcepts

IOFB REMOVAL SITE: Is IOFB > 4x4x4mm?
-Yes = Scleral Tunnel
- No = Sclerotomy (or through corneal wound?)

IOL: Is there adequate capsule for an IOL implant?
- Yes = implant IOL
- No = leave aphakic

TAMPONADE: Is there a retinal tear, RD or globe perforation?
- No = leave with BSS
- RT = Laser, Air
- RT/RD = RD repair, SF6, C3F8
- RD/Globe Perforation = RD repair, Silicone Oil

• If a choroidal hemorrhage has developed, a perforating injury is observed, or significant PVR is present, silicone oil may be instilled following IOFB removal.

INTRAOPERATIVE ANTIBIOTICS:
-Following PPV & IOFB extraction, consideration is given to intravitreal antibiotics.
-For endophthalmitis prophylaxis, intravitreal vancomycin (1.0mg/0.1ml) and Ceftazidime (2.25mg/0.1ml) is given.
-In pts allergic to penicillin, intravitreal amikacin (0.4mg/0.1ml) may be given instead of ceftazidime
-If gram stain demonstrates fungal yeast or hyphae forms, intravitreal amphotericin or voriconazole may be considered
-Give the rest of the Vanco & Ceftaz as subconj (usually 0.3mL is prepared)

Reference:

Current trends in the management of intraocular foreign bodies.  S. Yeh et. al, Curr Opin in Ophthal, 2008,19:225-233.