IOFB IN PENTRATING INJURIES TREATED WITH VITRECTOMY AND INTRAOCULAR MAGNET

1. INTRAOCULAR
FOREIGN BODIES
DR. AJAY I. DUDANI
M.S. D.N.B.F.C.P.S. D.O.M.S.
Vitreoretinal surgery & laser specialist
Consultant ,Bombay Hosp. & Research
Centre
Associate Professor K.J. Somaiya Hospital &
Medical College

2. INTRODUCTION

3. Introduction
Intraocular foreign bodies are a common
problem in ocular injuries
Upto 40 % of eyes with an open globe injury
contain at least one IOFB
Majority of such injuries occur at work place
Because they frequently occur in young &
productive members of society,
these injuries are costly both economically &
personally

4. Types of injuries
Hammering
Shooting a shot gun or a BB gun
Using a machine tool (at work place)
Assault
Motor vehicle accident

5. Types of foreign bodies
Common compositions include
Iron
Lead
Copper
Zinc
Silver
Gold
Platinum
Nickel
Glass
Plastic
wood

6. Locations of foreign bodies in eye
Most frequently enter eye through
cornea-65%
Sclera -25%
Limbus -10%
IOFB most frequently lodges in
Vitreous cavity-61%
Anterior chamber -15%
Retina-14%
Lens -8%
Subretinal space -5%

7. 40% of eyes with open globe injury contain at
least one IOFB
90% of IOFB’s are metallic ,
55-80% of which are magnetic
Metallic sharp projectiles produced in
hammering metal or stone penetrate ocular wall
with little disruption and have good prognosis.
IOFB’s from firing of gun or explosions and use
of machine tools are large and blunt, possess
more kinetic energy , cause more damage on
penetration and have a guarded prognosis

8. Evaluation
Thorough history – circumstances of trauma and
time elapsed since injury
Baseline visual acuity
Extent and location of wound
Iris colour
Lens status
Pupillary reaction
Intraocular pressure
Assessment of media clarity
Presence & location of retinal tears &
detachments

10. Thorough history very important
As it can help suspect or diagnose IOFB even in
severely traumatised eyes when examination is
limited by
Corneal haziness
Hyphaema
Cataract
Vitreous hemorrhage
Retinal detachment

11. Subtle ocular signs
Self sealing corneal wound
Change in size,shape of pupil
Mild iris heterochromia
Localised lenticular opacity
IOP asymmetry

12. Retroillumination detects red glow through superio-
nasal iris defect

13. HOLE IN IRIS

14. Principles in evaluation
Size, shape, location, number, type, magnetic
properties & entry path of foreign body should
be fully described
Composition of IOFB is important as it influences
the prognosis and method of extraction
Data should be collected as soon as possible as
progressive media opacification may preclude
further examination

15. Dictum
All traumatized eyes,
even those with little evidence
of penetrating injury
contain an IOFB
until
proved otherwise

16. Imaging
Done to either confirm or rule out presence
of IOFB
Plain x-ray( grossly insensitive)
CT scan
Echography
MRI scan

17. CT scan
Method of choice in open globe injury
High sensitivity
Suggests composition by radiodensity
2 dimensions, (axial & coronal) with thin
cuts less than 1.5mm
Negative CT rules out presence of metallic
foreign bodies for future MRI scan

19. CT scan - disadvantage
May not detect fragments smaller than
0.7mm in one dimension composed of
wood or lying adjacent to sclera

20. Echography
Detects radioluscent & radiodense IOFB’s
including cilium
Great sensitivity but low specificity (should be
interpreted in conjunction with other modalities)
In open globe injuries, it should be performed
cautiously through lid or intraoperatively after
entrance wound has been surgically closed.

21. Echography
Identifies precise site of IOFB when located
adjacent to sclera
Demonstrates ocular abnormalities including
retinal & choroidal detachments, vitreous
hemorrhage & exit wounds.
High frequency echography helpful for more
accurate description in case of anterior chamber
IOFB’s

22. MRI SCAN
Only test capable of detecting small plastic or
wood IOFB’s
Should be used only after CT has excluded
presence of metallic IOFB
Disadvantage- strong magnetic forces can
produce movement of a magnetic IOFB causing
further ocular damage.

23. Management
Goal- immediate closure of globe & removal of
IOFB
Delay in primary repair & IOFB removal > 24 hrs
produces 4 fold increase in risk of
endophthalmitis and severe vision loss
Eye shield
Broad spectrum antibiotics while awaiting
surgery

24. Tetanus prophylaxis
General history for surgical anaesthesia
Prompt IOFB removal before
encapsulation occurs facilitates removal &
limits intraocular toxicity

25. View of encapsulated foreign body (post vitrectomy)

26. Route of IOFB extractions
Methods depend on:
Location
Composition
Size
Presence of associated abnormalities
(cataract, endophthalmitis, vitreous
haemmorhage, retinal tear or detachment)

27. Techniques
External magnets
Internal rare earth magnets
Intraocular forceps
Scleral cut down (rarely)
Method that provides greatest control of eye
with least surgical trauma is chosen

28. Magnets
Have ability to align the ferromagnetic IOFB automatically in
axis of magnetic field & deliver the smallest diameter of
IOFB through sclerotomy
External magnets
They are bulky
Capable of generating great force
Restricted to use outside the eye
Provide less control

29. Internal magnets
Smaller
Generate less force
Can be used intraocularly
Capable of fine control
Create more unidirectional magnetic field
Require use of forceps for extraction as magnet
lacks strength for a transcleral delivery

30. Peyman – Raichand intraocular magnetic
tip with 3mm & 6mm intraocular extension

31. One should always pass IOFB through extraction wound in
plane of smallest cross section & grasp it with heaviest
instrument possible as it becomes exposed
It facilitates removal & decreases risk of dropping IOFB
back in the eye where it can strike the macula & cause
vision loss.
In case where IOFB may be dropped, liquid
perfluorocarbon should be placed in eye to damp the
impact & offer protection to retina.

32. Magnetic IOFB extraction by intraocular magnetic tip

33. Extraction by vitreous forceps
of IOFB embedded in retina
Clear corneal extraction of
large IOFB brought into
pupillary area by vitreous
forceps

34. Incorrect usage of magnets or inaccurate
localisation of IOFB may lead to serious
complications like impaction of IOFB into
lens or inadevertant traction on ocular
structures (vitreous base or retina)

35. Anterior chamber IOFB’s
Ideally should be removed through a second
limbal wound (paracentesis) 90-180degree from
where IOFB is located after primary corneal
wound closure.
Intraocular forceps can be used for non-
magnetic IOFB’s & viscoelastics are helpful in
maintaining anterior chamber & protecting
corneal endothelium

36. Intraretinal, Subretinal IOFB’s
Magnetic subretinal IOFB’s anterior to equator
can be removed through scleral cutdown
It involves delivering IOFB thro’ an overlying
Tshaped uveal & scleral flap with an external
magnet
Diathermy should be applied to uveal bed before
IOFB delivery to limit the risk of haemorhage
during transcleral passage

37. INTRAOCULAR FOREIGN BODY

38. Laser photocoagulation may be applied
before IOFB removal as hemorrhage
during extraction may hamper further
treatment.
Once IOFB is removed wound is closed &
scleral buckle may be placed

39. Cryocoagulation around area of retinal injury

40. Posterior segment IOFB
For posterior segment IOFB’s obscurred by
opaque media, too large for pars plana delivery
or embedded within retina , choroid or sclera ,
vitrectomy is required to ensure a minimally
traumatic extraction
Posterior hyaloid should always be removed

41. Vitrectomy also provides means of
excising any IOFB encapsulating fibrous
tissue.
It allows repair of retinal choroidal
damage,extraction of disrupted lens, trans
pupillary passage of IOFB into anterior
chamber for limbal wound delivery when
IOFB is too large fro pars plana delivery.

42. Treatment of associated ocular
damage
Retinal tears & detachment
Cataract formation

43. Treatment of retinal tears &
detachment
Retinal breaks are of 2 types:
1. Those located at IOFB impaction site &
2. Others distant from the site.
Demarcating laser, cryotherapy is controversial
If retinal detachment – vitrectomy, retinopexy,
gas tamponade, scleral buckle

44. Exoplant placed over retinal tear

45. Treatment of Cataract formation
Usually IOFB does not necessarily cause cataract
Unless risk of siderosis or loss to followup is high, the
IOFB & lens may be left insitu
Otherwise IOFB is extracted first , lens is extracted
second,& IOL implanted simultaneously
In cases of lens induced sterile endophthalmitis,
lensectomy may be done thro’ an anterior appraoch or
pars plana approach

46. Complications
Endophthalmitis
Retinal detachment with proliferative
vitreoretinopathy
Metallosis
-siderosis
-chalcosis
Subretinal neovascularisation

47. Endophthalmitis
In 8-13% of IOFB injuries
30% in organic or soil contaminated IOFB’s
Total vision loss occurs in 2/3rds
Risk factors include
-age >50yrs
-delayed presentation >24hrs after injury
-steel IOFB
Bacteria
-Bacillus (destructive, 75% eyes need
enucleation)
-Staph. Epidermidis, Streptococcus

48. Treatment of endophthalmitis
Vitrectomy –
culture of IOFB & sample of vitreous
Intravitreal antibiotics
-vancomycin 1mg
-ceftazidime 2.25mg
-amikacin 200-400micrograms

49. I.V. antibiotics
-vancomycin plus ceftazidime or ciprofloxacin
-Gentamycin does not consistently achieve
therapeutic intravitreal levels
- Use of corticosteroids in controversial

50. Retinal detachment with
proliferative vitreoretinopathy
Macular wrinkling
Subretinal fibrosis
Vision loss 5/200 or worse in 8%
Complete pars plana vitrectomy with removal of
posterior hyaloid is best prevention for PVR

51. Siderosis
Retained intraocular iron
Time of onset & degree vary with iron
content & location of IOFB
Accumulation of iron seen histologically in
cells of RPE, corneal epithelium, lens
epithelium, pupillary constrictor muscles,
trabecular meshwork & pars plana

52. Signs of siderosis
Iris heterochromia
Mydriasis
Decreased VA
Dark brown deposition beneath anterior
lens capsule
Cataract

53. Siderosis

54. ERG abnormality occurs before decrease in
visual acuity .
Initial supernormal signal followed by
progressive decrease in b-wave amplitude.
Implicit time is normal.
Changes progressive & irreversible despite iofb
removal
EOG dark adaptation study abnormal
Visual prognosis good with most eyes having
vision 20/40 or better.

55. Chalcosis
Copper retention
Vision loss depends on copper concentration
Pure copper IOFB causes rapidly progressive
severe purulent panophthalmitis leading to
pthisis bulbi
Treatment-removal of cuprous material to
prevent further damage

56. Alloys with > 85% copper cause vision loss by
depositing copper in descemet’s membrane,
vitreous cavity, internal limiting membrane
Signs-KF rings, greenish refractile deposits in
ILM, anterior subcapsular (sunflower) cataracts,
greenish discoloration of iris & vitreous
90% eyes –vision is 20/60 or better
<85% copper- no discernible copper deposition
& vision loss

57. Subretinal neovascularisation
Uncommon but serious whenever Bruch’s
membrane is disrupted

58. Summary
Intraocular IOFB’s are rather variable in presentation,
outcome & prognosis
The final resting place of IOFB & damage caused by it
depend on several factors , ------
--size ,
--shape,
--momentum of object at time of impact &
--site of ocular penetration
In addition to initial damage, the risk of endophthalmitis
& subsequent scarring play an important role in planning
surgical intervention

59. Summary
With increased awareness & advanced surgical
techniques the outcome & prognosis for these
potentially devastating injuries have substantially
improved.
Lastly protecting eyes is especially important
when working with machinery that could cause
chips of wood or metal to splinter as well as
other equipments
Protective eye wear can act as a simple means
of primary barrier against such injuries.

60. Our study with the new
HANDSHAKE maneuver
200 IOFB’S – largest being 5mm
2 iofb’s on disc with CRAO (no PL)
8 cases of endophthalmitis
Procedure includes 3 port PPV with IOFB
removal with 18 G intravitreal magnet
PVD induced in all cases
HANDSHAKE MANEUVER used

61. Catch IOFB in vitreous base and deliver it out
with magnet handle applied at sclerostomy site
(like external magnet)
Silicone oil was used in 80 cases of RD
Endolaser was given to IOFB site on retina
Prognosis - vision 6/12 - 50 cases
6/24 - 40 cases
6/60 - 70 cases
CF - 40 cases