Optometty (2006) 77, 446-449

Literatur-Nr.: 16

Standort: SIL­Ordner II

Silicone oiL emulsification in the anterior chamber after

vitreoretinal surgery

Dennis J. Light, 0.0.

Department of Veterans Affairs, Eastern Colorado Health Care System Eye Clinic, Pueblo, Colorado .•

KEYWORDS

Silicone oil;

Endotamponade;Retinal detachmen~;Keratopathy;Glaucoma;Cataract

Abstract

BACKGROUND: The use of &iliconeoil as an endotamponade for the treatment of complicated retinaIdetachment is common, hut lang-term complications can oceur if the oil is not removed later. Thisartic1edocuments a case of emulsified silicone oil migration into the anterior chamber after vitreoretinaIsurgery and provides a diseussion and review of comrnon anterior segment eomplieations trom thiscondition.

CASE REPORT: A 59-year-old man reported to the eye clinic complaining of a "growth •• over bis righteye 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 posteriorehamber after a previous retinal detachrnent repair. Tbe patient was referred for surgical removal of thisoily obstruetion. Although surgical treatment was delayed for 18 months, his vision improved and bisintraocular pressure was lowered through surgieal and medical management.CONCLUSIONS: The use of silicone oil as an endotamponade in cases of complex retina! detachmenthas become common, but it also may lead to postoperative complications if it is not surgically removedIater. This case highlights possible complications from the migration of emuIsified silicone oil into theanterior chamber and illustrates the importance of follow-up care for every ophthalmie surgicalprocedure.Optometry 2006;77:446-449

The use of silicone oil in complex vitreoretinal surgery

was first introduced in 1962.1 Its injection into the vitreouscavity.to serve as an endotamponade has become a standard

technique and, when combined with vitreoretinal surgery,

has been used sÜccessfully in the repair of proliferativevitreoretinopathy, prolifera,tive diabetic retinopathy, giantretinal tears, and ocular trauma. 2 .Silicone oll has been

known to emu1sify and migrate into various locations withinthe globe.3 Because this can lead to long-term cornplica­tions, such as cornea! decompensation, cataract, and glau-

Correspondingauthor: DennisJ. Light, O.D., Departmentof VeteransAffairs,Eastern Colorado HenlthCare SystemEye Clinic, 4112 OutlookB1vd.,Pueblo,Colorado81008.

E-mail: dennis.light@va.gov

coma, it should be removed after adequate duration ofendotamponade.4

(ase report

A 59-year-old man reported to the eye clinic complaining ofa "growth" over bis right eye that had increased in size overthe last month according to his wife's observation. Hedenied any asthenopia but reported that he "had very little

vision" in this eye and that Hit might have gotten a littleworse:'

His medical history included a '3S-year history of type 2diabetes mellitus for which he had taken insulin for the last

15 years. His last Ale hemoglobin test, a measure of the

1529-1839/06/$ -see front matter © 2006 American Optometrie Association All rights reserved.doi:lO.l 016/j.optm.2006.04.l19

Oenni" J. Light ClinicaL Ca,,,

Figure 1 A "reverse pseudohypopyon" of emulsified silicone oil drop·

lets in the superior anterior chamber.

--""!1lilunt 01' glycnsylated h~moglobin in the blilod and a goodesrim;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 backpain. kidncy stones. gallbladder disea~c. and depression. Hismedications inc!uued insulin ntlvolin. rosiglitazone maleate.

and metarürmin HeL für his diabetes; Iisinopril. cycloben­

l.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 includedprevious "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 refrac­

lion was unable 10 improve the vision in his right eye whiiehis !efl eye was best conected to 20/60' 2. Pupils were 4mmand wund but with minimal reactiol1s in both eves (OU). A

~. ,.:rade ! + right relative afferent pupillary defect waspresent.

Billmicroscopy showed clear amI quiet conjlloctival tis­sues OU. The cornea was clear wilhollt ederna or endothe­

baI strimions OU. In thc right eye. there was a globule of

silicone oil oceupying 40o/c of the superior anterio! chamberthat would O)ove sJightly with head tilt to either shoulder

(see Figure 1 ). Thc globulctilled the entire superior anteriorchamber and contacted the corneal endothelium amI the

amerior iris. 11 was composed 01' multiple, smalf, semi­

opaque, nil droplets thm gave a "rock candy" appearance 10the 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 werenormal, 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 fordense vitreous debris and hall' 0.0. Because 01' the cloud-

447

iness 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. Therewas 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 ! yearpreviously. 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! sllrgicallywas based on the patiem's des ire to improve his cosmetic

appearance (remove "thc grO\vth"), improve the reduction ofvisual acuity, decrease tbe elevated intraocular presslIre. rc­move the prescnee of comeal touch. and remove thc catamc!.

Unforlunately, this patient had unstablc angina associ­

ared with poofly controlled hypel1cnsion causing him ro

canee! his surgical procedure. He returned for eare I yearlater. and a! thm time his vision had dccreased to lightperception 0.0..and his imraocular prcssure had risen to 28mmHg 0.0. He was prescribed O.2o/c brimonidine tartrate

twiee a day O.D., which lowered the intraocuJar pressure to18 mmHg O.D.

His SUHrcrv was delaved again after he suffered a tran-'-..' "' ..J ••••

sient ischemic aHack .that warranted flIrther cardiac and

carotid artery evaluations. Six months later, however. he

underwent successfuJ surgicaJ removal of the silicone oil0.0. with phacoemulsification and posterior charnber in­traocular lens implantation. One day postoperative]y, visionhad improved to 4/1600.0. although there was consider­

able comeal edema Iikely from endothelial cell los5 and

dysfunction from the silicone oil contact. His intraocular

pressure was 13 mmHg 0.0. Fundus examination tindingsshowed extensive panretinaJ photocoaglliation with areas offibrosis. auenuated vessels. ghost (sclerotic) vesseIs. andmoderate 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 amberintraocular 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 properanatomie position, while its surface tension helps keep itthere. This also keeps vitreal fluid from entering through aretinal break into the subretinal space, thus allowing for astrong chorioretinal adhesion to take place.6

The use of silicone oll as a tamponade has a fewadvantages compared with long-lasting gases used for sim­ilar purposes. Unlike the gas-filled eye, which leaves thepatient with no useful vision, silicone oil is transparent (itdoes not mix with intraocular fluids or blood) and perrnitsthe patient to see after proper refraction.7 The use of siliconeoil eliminates the need for facedown positioning duringhealing, and it allows for high altitude and air travel (gasexpands at higher altitudes). Perhaps its biggest advantage isthat 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 hasc;sociated risks. Over time, silicone oil bas a tendency to

•.•mulsify and break into smaller oil droplets, which have apropensity to leak through very small openings.9 The drop­lets may egress surgical incision sites or rnigrate throughanatomically compromised areas such as through brokenzonules.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 oilto some degree has been reported to occur in 56% tO.1 00%of cases over aperiod of months· to years.3.10 Multiplefactors may contribute to silicone oil emulsification, inc1ud­ing the use oflow viscosity silicone oils (higher viscosityoils restriet mechanical emul sificati on),9 residual fluid in thevitreous cavity, and hemorrhage or leakage of other bloodconstituents from the breakdown of the blood-aqueousbarrier after surgery.J5.J6 Anterior segment complicationsassociated with the use of silicone oil include alterations ofcorneal structure or integrity,17 increased intraocular pres-

----'lre,18and development or progression of cataract.4Silicone oil is toxic to the cornea. Specular microscopic

studies have shown the main corneal complication to beendothelial cell darnage inc1uding decreased cell density,pleomorphism, and necrosis. If allowed to enter the anteriorchamber, silicone oll will eventually lead to corneal endo­thelialcell damage, edema, or band keratopathy.19 Rates ofkeratopathy after silicone oil injection have been reported torange 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 anteriorchamber may act as a physical barrier and interfere withcorneal homeostasis.20 When the oi! is removed later dam­

aged endothelium may allow for excess stromal hydrationand lead to corneal edema.

The prevalence of elevated intraocular press ure aftersilicone oil injection has been reported to range from 1.5%~o.48%,21 Silicone oil in the vitreous cavity may push thems or lens forward resulting in pupillary block or directangle obstruction. Emulsified silicone oil also may fill the

Optometry, Vol 77, No 9, September 2006

anterior chamber, infiltrate the trabecular meshwork, anddecrease the aqueous outflow.22 Outflow in this case isaffected initially through direct obstruction, aIthough histo­logie studies have shown that silicone damages the outftowpathway with a loss of cellularity and fibrosis. Foreign bodygranuloma containing macrophages laden with oil also maydevelop.22.23 Clinically significant increased intraocularpressure after silicone oil injection usually can be controlledby topical antiglaucoma medications and is reversible inmost patients after oil removal.23

By preventing the anterior migration cf silicone oil fromthe vitreous cavity, the risk of damage to the cornea anddevelopment of elevated intraocular pressure can be re·duced?4 A prophylactic inferior peripheral iridotomy maybe placed at the time of silicone injection. The buoyancy ofthe silicone oil coupled with the inferior placement of theiridotomy encourages a natural flow of aqueous from theposterior chamber into the anterior ehamber. This helpsprevent pupillary block and indirectly limits the access andmigration 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 lensesthat appear relative1y clear at the time of silicone oil re­moval will also develop a clinically significant cataraet after2 years?6 Obstruction of normal metabolie exchange at thesilicone-Iens interface results in cataract fonnationP Cat­

aract formation may be delayed by the early removal ofsilicone oil,28but it is considered to be almost unavoidable.

The reported incidence of alterations to the cornealstructure or integrity, increased intraocular pressure, andcataract 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, theduration of silicone oil endotamponade, the presence ofinferior iridotomy, and previous surgical history.

Surgical removal of silicone oil significantly increasesthe likelihood of improved visual acuity and reduces the riskof keratopathy, secondary glaucoma, and cataract progres­sion.4 The timing of silicone oil removal remains contco­versial,29.3obut in most cases, removal is recommended 2 to3 months after surgery31 or as soon as a stable retinalsituation is achieved. This can be difficult to assess. Clinicalsigns include a quieting of inflammation, a whitening of anyepiretinal membrane formation, and, most important, a lackof change in the appearance or configuration of the retina.32Contraindications for removal are unclear but include the

presenee of profound hypotony,33 In any case, there is anincreased risk of retinal detachment after oil removal. Mostretinal redetachments occur within the first 3 months afterremoval of silicone oil. Six months after oiI removal, aretinal redetachment becomes unlikely. 34

Summary

The use of silicone oil as an endotamponade in cases ofcomplicated 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 siliconeoil reduces the risk of these eomplications and signifieantlyincreases the likelihood of improved visual aeuity. Removalis reeommended as soon as the tamponade effect is nolonger needed. This case shows the importanee of follow-upcare for every ophthalmie surgical procedure. The optome­trist should be familiar with the technique and materialsused during ophthalmie surgery and be aware ofthe clinicalsigns 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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