topiramate is a sulfa - derivative antiepileptic drug which is also used for other indications such as migraine , personality disorders , weight loss , neuropathic pain and , recently , essential tremor [ 1 , 2 ] .
the pharmacodynamic picture of this drug generally reflects the modulation of voltage - gated sodium and calcium channels , increase of gabaergic inhibition , blockage of glutamate receptors and mild carbonic anhydrase inhibition . to date , several side effects of this drug are reported , of which ophthalmic manifestations are of special importance .
the most clinically significant ophthalmic side effects are angle - closure glaucoma , myopic shift , diplopia and nystagmus
. the precise mechanisms responsible for such adverse effects are , however , not completely understood .
serous choroidal detachment ( transudation of fluid into the suprachoroidal space ) may be due to globe hypotony of any etiology or exudation of serum caused by inflammation or other causes .
moreover , there are some instances in which the occurrence of choroidal detachment is not explainable by common mechanisms . to our knowledge ,
massive choroidal detachment following the administration of topiramate has never been described in previous case reports .
the purpose of this report was to illustrate the clinical and paraclinical features of a patient who experienced the above - mentioned adverse event .
we also aimed to discuss the possible pathogenic links of topiramate by comparing the features of our case with those of cases previously reported in the literature .
a 79-year - old male was admitted to our center for further evaluation of acute bilateral painless decline of vision .
the patient 's past clinical history included 80 mg / day aspirin intake due to unstable angina for 11 years .
the patient had no significant neurological disorder until 1 month before admission , when he experienced essential tremor .
as a result , treatment with topiramate 50 mg / day and propranolol 40 mg / day was started 2 weeks before his admission due to ophthalmic symptoms .
he underwent uncomplicated cataract surgery 11 years ago for the right eye and 9 years ago for the left eye , and both eyes had intraocular lenses .
on ophthalmologic examination , best - corrected visual acuity was 20/800 od and 20/600 os .
pupillary reactions to light and near stimuli were normal , and no pupillary afferent defect was present .
intraocular pressure was 10 mm hg in the right and 11 mm hg in the left eye .
retinal examination revealed posterior pole drusen compatible with mild dry age - related macular degeneration and notable choroidal detachments in all quadrants of the periphery ( fig . 
 1 ) , which were confirmed by ultrasonography ( fig . 
 2 ) .
the administration of topiramate was discontinued as a potential causative agent for this condition ; however , we did not reduce the dosage of propranolol .
this improvement continued until day 7 , when visual acuity gradually exceeded to 20/25 od and 20/30 os . by the end of day 7 , choroidal detachment resolved as well .
however , it is worth noting that in a study by the national registry of drug - induced ocular side effects , 9 cases of suprachoroidal effusion were concisely mentioned regardless of the severity of their complication .
the data on these subjects were extracted from the records of the world health organization or other related / similar organizations . nevertheless , to the best of our knowledge ,
neither precise features of these cases , e.g. the severity of effusion , were published elsewhere , nor any of them were specified to present massive choroidal detachment .
a review of the ophthalmology literature reveals that , to date , there are several reports describing bilateral angle closure following topiramate intake [ 4 , 7 , 8 , 9 ] .
our patient did not exhibit myopic changes or a shallow anterior chamber , although such side effects have been frequently observed with the use of this drug .
the term  ciliochoroidal effusion syndrome was first proposed by ikeda et al .   to describe the phenomena induced by topiramate and other sulfa derivatives .
this syndrome represents a category of symptoms including ciliochoroidal effusion , forward displacement of the lens - iris diaphragm and , consequently , angle narrowing and myopic shift .
accordingly , in our case choroidal effusion without development of angle closure or myopic shift could be due to lack of crystalline lens .
as mentioned previously , the main cause of choroidal detachment is generally believed to be ocular hypotony following surgical procedures . in our literature review
, we could identify an interesting case by doherty et al .   that shares decisive common features with ours .
taking together , four main similarities are worth noting : ( 1 ) both patients had a past history of uncomplicated cataract surgery ; ( 2 ) intraocular pressure was within normal limits in both patients ; ( 3 ) dorzolamide and topiramate are both sulfa - derivative drugs , and ( 4 ) similar to dorzolamide which is a carbonic anhydrase antagonist , topiramate is also suggested to be  a mild carbonic anhydrase inhibitor .
accordingly , the authors concluded that the cause of choroidal detachment is not always hypotony and postulated that it may also be due to hypersensitivity to dorzolamide .
our case provides further evidence in favor of this hypothesis , and this raises the question whether the cause of choroidal detachment in our case was hypersensitivity to topiramate as this is a sulfa - derivative drug as well . from another point of view
, it is well known that carbonic anhydrase antagonists can cause choroidal detachment , and this may explain why the administration of dorzolamide and topiramate results in this adverse effect . as a conclusion ,
we propose that the administration of topiramate and perhaps other sulfa - derivative drugs might be eligible to be added as a differential diagnosis of choroidal detachment .
 topiramate is a sulfa - derivative antiepileptic drug which is also used for other indications such as essential tremor . a 79-year - old male was admitted to our center due to acute bilateral painless decline of vision . 
 one month before admission , he had experienced essential tremor and treatment with topiramate 50 mg / day and propranolol 40 mg / day . 
 best - corrected visual acuity was 20/800 od and 20/600 os . 
 both eyes had normal anterior chamber depths and irides . 
 intraocular pressure was 10 mm hg in the right eye and 11 mm hg in the left eye . 
 retinal examination showed notable choroidal detachments in all quadrants of the periphery , which were confirmed by ultrasonography . 
 refraction showed no myopic shift . 
 the administration of topiramate was discontinued as a potential causative agent for this condition . during follow - up , choroidal detachment and visual acuity 
 gradually resolved . in this study 
 , we described the first case of isolated massive choroidal detachment induced by topiramate . 
Introduction
Case Report
Discussion
Disclosure Statement