primary cysts have no clear aetiology and tend to arise spontaneously , while secondary cysts result from a known aetiology such as trauma , surgery or medications [ 1 , 2 ] .
primary iris cysts may arise from either the iris pigment epithelium ( ipe ) or the iris stroma [ 2 , 3 ] . in rare instances ,
an ipe cyst may dislodge and pass from the posterior chamber through the pupil , resulting in a free - floating cyst in the anterior chamber .
we describe such a case , where a free - floating iris cyst within the anterior chamber was observed in the setting of recurrent iritis .
we also discuss the complications , significance of iritis and management of free - floating iris cysts .
a 39-year - old male with a 5-year history of mild recurrent iritis ( 6 episodes ) affecting the right eye was found to have a free - floating iris cyst of approximately 0.5 by 0.8 mm within his right anterior chamber ( fig .
mobilisation of the cyst occurred with head tilt but never caused pain or visual compromise ( fig .
there were small fluctuations in the size of the iris cyst but no gross or rapid enlargement .
his past medical history included reactive arthritis , and he tested positive for hla - b27 .
there was no past history of ocular surgery or trauma , and no family history of ocular disease .
all episodes of mild iritis affected the anterior segment only and were treated effectively with dexamethasone ophthalmic drops for 26 weeks .
he did not have keratic precipitates on his corneal endothelium , anterior or posterior synechiae .
the differential diagnosis includes iris stromal cyst , iris or ciliary body melanoma , adenoma of the ipe and medulloepithelioma .
ipe cysts have been associated with ocular complications such as angle closure glaucoma , plateau iris syndrome , and secondary pigment dispersion syndrome . however , these complications are uncommon .
a case series of 234 patients found that none of the ipe cysts grew larger after a mean follow - up period of 35 months .
in particular , no visual or ocular complications were reported in patients with free - floating iris cysts .
a study of 62 patients sought to determine current or prior ocular disorders associated with iris cysts [ 1 , 7 ] .
four patients had a history of iritis ; however , ocular inflammation was either mild or in remission in 3 of the 4 patients [ 1 , 7 ] . only 1 patient presented with severe iritis and a large iris cyst , which regressed in size upon resolution of the iritis . in another study of 14 patients with iritis , 3 patients showed evidence of new iris cyst formation .
this suggests that ocular inflammatory disorders may contribute to the development of iris cysts or cause pre - existing cysts to enlarge .
however , the paucity of further evidence means that the full extent of this relationship remains theoretical . in our patient
we could not find an association between the small fluctuations in the size of the iris cyst and his episodes of iritis .
asymptomatic non - progressive iris cysts are best left alone , and the indications for surgical removal include significant visual disturbances , rapid increase in cyst size over a short period of time , evidence of recurrent iridocyclitis , corneal endothelial touch by the cyst or secondary glaucoma [ 3 , 5 ] .
the use of neodymium - doped yttrium aluminium garnet laser to collapse the iris cyst has also shown favourable results in symptomatic patients [ 3 , 9 , 10 ] . our patient remained asymptomatic ; thus , surgical removal or laser treatment was not warranted .
few have been implicated in causing visual disturbance or ocular complications , warranting their removal .
the paucity of available evidence means that the association between recurrent iritis and the development or progression of free - floating iris cysts remains inconclusive .
 purposewe describe an unusual clinical finding of a free - floating iris cyst in a patient with recurrent iritis.methodthe clinical finding of a free - floating iris cyst was recorded using slit - lamp photography.resultsa 39-year - old male with a 5-year history of recurrent right iritis was found to have a small mobile iris cyst within his right anterior chamber , first identified 3 years ago . 
 the patient did not experience any discomfort or visual symptoms resulting from the cyst.conclusionsurgical removal is not indicated for asymptomatic non - progressive free - floating iris cysts . 
 the significance of a free - floating iris cyst in the setting of recurrent iritis remains unknown . 