Download Silicone oiLemulsification in the anterior chamber after vitreoretinal

Literatur-Nr.: 16
Optometty (2006) 77, 446-449
Standort: SILOrdner II
Silicone oiL emulsification
vitreoretinal surgery
in the anterior chamber after
Dennis J. Light, 0.0.
Department of Veterans Affairs, Eastern Colorado Health Care System
Eye Clinic, Pueblo, Colorado .
•
KEYWORDS
Abstract
Silicone oil;
Endotamponade;
Retinal detachmen~;
Keratopathy;
Glaucoma;
Cataract
BACKGROUND: The use of &iliconeoil as an endotamponade for the treatment of complicated retinaI
detachment is common, hut lang-term complications can oceur if the oil is not removed later. This
artic1e documents a case of emulsified silicone oil migration into the anterior chamber after vitreoretinaI
surgery and provides a diseussion and review of comrnon anterior segment eomplieations trom this
condition.
CASE REPORT:
A 59-year-old man reported to the eye clinic complaining of a "growth •• over bis right
eye that had increased in size over the last month. Stit tamp examination found a "reverse pseudohypopyon" iri the right eye, which was actuaIly emutsified silicone oil that had migrated from the posterior
ehamber after a previous retinal detachrnent repair. Tbe patient was referred for surgical removal of this
oily obstruetion. Although surgical treatment was delayed for 18 months, his vision improved and bis
intraocular pressure was lowered through surgieal and medical management.
CONCLUSIONS:
The use of silicone oil as an endotamponade in cases of complex retina! detachment
has become common, but it also may lead to postoperative complications if it is not surgically removed
Iater. This case highlights possible complications from the migration of emuIsified silicone oil into the
anterior chamber and illustrates the importance of follow-up care for every ophthalmie surgical
procedure.
Optometry 2006;77:446-449
The use of silicone oil in complex vitreoretinal
was first introduced in 1962.1 Its injection into the
cavity.to serve as an endotamponade has become a
technique and, when combined with vitreoretinal
surgery
vitreous
standard
surgery,
has been used sÜccessfully in the repair of proliferative
vitreoretinopathy,
prolifera,tive diabetic retinopathy,
giant
retinal tears, and ocular trauma. 2 . Silicone oll has been
known to emu1sify and migrate into various locations within
the globe.3 Because this can lead to long-term cornplications, such as cornea! decompensation, cataract, and glau-
Correspondingauthor: Dennis J. Light, O.D., Departmentof Veterans
Affairs,Eastern Colorado Henlth Care SystemEye Clinic, 4112 Outlook
B1vd.,Pueblo, Colorado 81008.
E-mail: [email protected]
coma, it should
endotamponade.4
be removed
after
adequate
duration
of
(ase report
A 59-year-old man reported to the eye clinic complaining
of
a "growth" over bis right eye that had increased in size over
the last month according to his wife's observation.
He
denied any asthenopia but reported that he "had very little
vision" in this eye and that Hit might have gotten a little
worse:'
His medical history included a '3S-year history of type 2
diabetes mellitus for which he had taken insulin for the last
15 years. His last Ale
1529-1839/06/$ -see front matter © 2006 American Optometrie Association All rights reserved.
doi:lO.l 016/j.optm.2006.04.l19
hemoglobin
test, a measure
of the
Oenni"
J.
Light
ClinicaL
Ca,,,
447
iness
Figure 1
A "reverse
pseudohypopyon"
lets in the superior anterior
of emulsified
silicone
oil drop·
chamber.
--""!1lilunt 01' glycnsylated h~moglobin in the blilod and a good
esrim;1lOr pI' htH\- \IcH the diabetes has been managed over
the pr~~\'ious 3 rnonlhs. \las 8.Y{;. He also had hypertension.
rhcumatniJ
arthritis. hypcrlipidemia.
duonie lower back
pain. kidncy stones. gallbladder disea~c. and depression. His
medications inc!uued insulin ntlvolin. rosiglitazone maleate.
and metarürmin HeL für his diabetes; Iisinopril. cyclobenl.aprine HeL hydrocblorothiazide.
and metoprolol für his
~.
hypertension; gemtlbr~nil for his hyperlipidemia:
and amitrypliline Hel. for his depression. He reported no allergies.
His ocular hhtory was somcwhat sketchy but included
previous "laser treatments for diabetö in bOlh eyes" and a
retinal detad111lCl1l repair 01' his right cye ! yeur previously.
His uncorrccted visua! <lcuitics were 1/160 in the right eye
(O.D.) amI 20170 2 in the !en eye (O.5.t Manifest refraclion was unable 10 improve the vision in his right eye whiie
his !efl eye was best conected to 20/60' 2. Pupils were 4mm
and wund but with minimal reactiol1s in both eves (OU). A
,
.:rade ! + right relative afferent pupillary defect was
present.
Billmicroscopy showed clear amI quiet conjlloctival tissues OU. The cornea was clear wilhollt ederna or endothebaI strimions OU. In thc right eye. there was a globule of
silicone oil oceupying 40o/c of the superior anterio! chamber
that would O)ove sJightly with head tilt to either shoulder
(see Figure 1 ). Thc globulctilled
the entire superior anterior
chamber and contacted the corneal endothelium amI the
amerior iris. 11 was composed 01' multiple, smalf, semiopaque, nil droplets thm gave a "rock candy" appearance 10
the globule. Gonioscopy llndings showed the angle open to
the ciliary body inferiorly 0.0.. but there was no view
through the globule 10 the superior angle. His irides were
normal, w1lh no rubcoslS 01' indotomy present in either eye.
Grade 3+ l111clear sclerosis O.D. and grade 1 + nlldear
sclerosis O.S. were prescnt. lntn.lOClllar pressures by Gold·
mann applan::.llion tonometry wert' 18 mmHg O.D. and 13
rnmHg O.S. at ]0:02 AM.
DiJared fundus examinariofl fj nJings were remarkabJe for
dense vitreous debris and hall' 0.0. Because 01' the cloud-
01'
the media. a limiled
view ur the fundus
was
available O.D .. and unfortunately. fine retinal detail could
not be viewed. A red reflex was presenr in aH quadrants.
B-scan ultrasonography.
although indicalcd in cases in
which the retina cannol be visualized cleady to help determine the presence or absence of retina I detachment. was not
performed owing to unavailability 01' the instrument. There
was 360-degree panretinal pholocoagulation
0.5. with flbrous vascular scarring temporal to thc rnacula.
This patient had emuJsified silicone oil in the anterior
chamber 01' the right eye after retinal detachment repair ! year
previously. He was referred to a vÜreoretinal specialist for
evaluation and surgical rem ova] of the emulsified silicone oil.
The decision to remove the emulsiflcd silicone oi! sllrgically
was based on the patiem's des ire to improve his cosmetic
appearance (remove "thc grO\vth"), improve the reduction of
visual acuity, decrease tbe elevated intraocular presslIre. rcmove the prescnee of comeal touch. and remove thc catamc!.
Unforlunately,
this patient had unstablc angina associared with poofly controlled hypel1cnsion causing him ro
canee! his surgical procedure. He returned for eare I year
later. and a! thm time his vision had dccreased to light
perception 0.0..and his imraocular prcssure had risen to 28
mmHg 0.0. He was prescribed O.2o/c brimonidine tartrate
twiee a day O.D., which lowered the intraocuJar pressure to
18 mmHg O.D.
His SUHrcrv was delaved again after he suffered a transient ischemic aHack .that warranted flIrther cardiac and
'-..'
"'
..J
••••
carotid artery evaluations. Six months later, however. he
underwent successfuJ surgicaJ removal of the silicone oil
0.0. with phacoemulsification and posterior charnber intraocular lens implantation. One day postoperative]y,
vision
had improved to 4/1600.0. although there was considerable comeal edema Iikely from endothelial cell los5 and
dysfunction from the silicone oil contact. His intraocular
pressure was 13 mmHg 0.0. Fundus examination tindings
showed extensive panretinaJ photocoaglliation
with areas of
fibrosis. auenuated vessels. ghost (sclerotic) vesseIs. and
moderate optic nerve pa]]or 0.0. believed to have resulted
from previous diabetic optic neuropathy.
At his 6-monrh postoperative visit, vision had improved
to 20/] 50 0.0. The comea O.D. continued to show mild
edema without endothelial striation. The posterior eh amber
intraocular lens implant O.D. was centered and elear. The
intraocular
pressure was 16 mmHg O.D. on O.2'k brimonidinc tartrate bid.
Discussion
Silicone oil often is placed in the vitreoretinal cavily as an
aid in the repair of proliferative vitreoretinopathy,
prolifcrative cliabetic rctinopathy, reCllrrent retinal dClachmenh.
giant retinal tears. macular hole. viral retinitis. and lTaumatic
retinal injuries. 5 Ir has a densily lower than water and Illuch
greater surface tensions. making it an dfective
intraocubr
448
tamponade. When injected into the vitreal cavity, its buoyancy mechanically pushes the retina back into its proper
anatomie position, while its surface tension helps keep it
there. This also keeps vitreal fluid from entering through a
retinal break into the subretinal space, thus allowing for a
strong chorioretinal adhesion to take place.6
The use of silicone oll as a tamponade has a few
advantages compared with long-lasting gases used for similar purposes. Unlike the gas-filled eye, which leaves the
patient with no useful vision, silicone oil is transparent (it
does not mix with intraocular fluids or blood) and perrnits
the patient to see after proper refraction.7 The use of silicone
oil eliminates the need for facedown positioning during
healing, and it allows for high altitude and air travel (gas
expands at higher altitudes). Perhaps its biggest advantage is
that it does not dissolve, allowing for longer-acting tamponade in the repair of very complicated retinal detachments.8
This permanence of silicbne oil in ocular tissue has
c;sociated risks. Over time, silicone oil bas a tendency to
•.•mulsify and break into smaller oil droplets, which have a
propensity to leak through very small openings.9 The droplets may egress surgical incision sites or rnigrate through
anatomically compromised areas such as through broken
zonules.10 Migration has been observed in phakic, aphakic,
and pseudophakic eyes, and has been documented from
eyelidJ1•12 to optic nerveY·J4 Emulsification of silicone oil
to some degree has been reported to occur in 56% tO.1 00%
of cases over aperiod of months· to years.3.10 Multiple
factors may contribute to silicone oil emulsification, inc1uding the use oflow viscosity silicone oils (higher viscosity
oils restriet mechanical emul sificati on),9 residual fluid in the
vitreous cavity, and hemorrhage or leakage of other blood
constituents from the breakdown of the blood-aqueous
barrier after surgery.J5.J6 Anterior segment complications
associated with the use of silicone oil include alterations of
corneal structure or integrity,17 increased intraocular pres----'lre,18and development or progression of cataract.4
Silicone oil is toxic to the cornea. Specular microscopic
studies have shown the main corneal complication to be
endothelial cell darnage inc1uding decreased cell density,
pleomorphism, and necrosis. If allowed to enter the anterior
chamber, silicone oll will eventually lead to corneal endothelialcell damage, edema, or band keratopathy.19 Rates of
keratopathy after silicone oil injection have been reported to
range from 4.5% to 63%.2 As seen in this case report,
corneal edema may riot always be present on initial presentation, even if there is significant corneal touch and presumed endothelial damage. Silicone oil in the anterior
chamber may act as a physical barrier and interfere with
corneal homeostasis.20 When the oi! is removed later damaged endothelium may allow for excess stromal hydration
and lead to corneal edema.
The prevalence of elevated intraocular press ure after
silicone oil injection has been reported to range from 1.5%
~o.48%,21 Silicone oil in the vitreous cavity may push the
ms or lens forward resulting in pupillary block or direct
angle obstruction. Emulsified silicone oil also may fill the
Optometry,
Vol 77, No 9, September
2006
anterior chamber, infiltrate the trabecular meshwork, and
decrease the aqueous outflow.22 Outflow in this case is
affected initially through direct obstruction, aIthough histologie studies have shown that silicone damages the outftow
pathway with a loss of cellularity and fibrosis. Foreign body
granuloma containing macrophages laden with oil also may
develop.22.23 Clinically significant increased intraocular
pressure after silicone oil injection usually can be controlled
by topical antiglaucoma medications and is reversible in
most patients after oil removal.23
By preventing the anterior migration cf silicone oil from
the vitreous cavity, the risk of damage to the cornea and
development of elevated intraocular pressure can be re·
duced?4 A prophylactic inferior peripheral iridotomy may
be placed at the time of silicone injection. The buoyancy of
the silicone oil coupled with the inferior placement of the
iridotomy encourages a natural flow of aqueous from the
posterior chamber into the anterior eh amber. This helps
prevent pupillary block and indirectly limits the access and
migration of silicone oil into the anterior chamber.25
Cataracts can develop in nearly all eyes in wh ich silicone
oil remains in situ for a few months, and up to 60% of lenses
that appear relative1y clear at the time of silicone oil removal will also develop a clinically significant cataraet after
2 years?6 Obstruction of normal metabolie exchange at the
silicone-Iens interface results in cataract fonnationP Cataract formation may be delayed by the early removal of
silicone oil,28but it is considered to be almost unavoidable.
The reported incidence of alterations to the corneal
structure or integrity, increased intraocular pressure, and
cataract progression show a varied range of occurrence.
This variation can be attributed to a number of factors
including sampIe size, viscosity of silicone oi! used, the
duration of silicone oil endotamponade, the presence of
inferior iridotomy, and previous surgical history.
Surgical removal of silicone oil significantly increases
the likelihood of improved visual acuity and reduces the risk
of keratopathy, secondary glaucoma, and cataract progression.4 The timing of silicone oil removal remains contcoversial,29.3obut in most cases, removal is recommended 2 to
3 months after surgery31 or as soon as a stable retinal
situation is achieved. This can be difficult to assess. Clinical
signs include a quieting of inflammation, a whitening of any
epiretinal membrane formation, and, most important, a lack
of change in the appearance or configuration of the retina.32
Contraindications for removal are unclear but include the
presenee of profound hypotony,33 In any case, there is an
increased risk of retinal detachment after oil removal. Most
retinal redetachments occur within the first 3 months after
removal of silicone oil. Six months after oiI removal, a
retinal redetachment becomes unlikely. 34
Summary
The use of silicone oil as an endotamponade in cases of
complicated retina! detachment has become increasingly
Dennis
J.
Light
Clinical Care
common, but it is has been associated with alterations to the
corneal structure or integrity, increased intraoeular pressure,
and cataraet progression. Surgical removal of the silicone
oil reduces the risk of these eomplications and signifieantly
increases the likelihood of improved visual aeuity. Removal
is reeommended as soon as the tamponade effect is no
longer needed. This case shows the importanee of follow-up
care for every ophthalmie surgical procedure. The optometrist should be familiar with the technique and materials
used during ophthalmie surgery and be aware ofthe clinical
signs of potential eomplications.
Acknowledgments
The author acknowledges Robert Newcomb, O.D., GregoFy
__Kiracofe, O.D., and Wilbur Meiklejohn, O.D., for their
.ontributions to this case report.
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