a 30-year - old male presented in the emergency department with a history of bilateral blurring of vision of one - day duration .
since his systemic hypertension was not well controlled with this drug his physician had switched over to a combination of atenelol 50 mg with chlorthalidone 12.5 mg ( tenoric 50 , ipca pharmaceuticals ) .
refraction was done and his visual acuity was improving to 20/20 in both eyes with a spherical correction of -5 diopter sphere ( ds ) .
a cycloplegic refraction revealed a value of -3 ds/-0.5 diopter cylinder ( dc ) x 80 in the right eye and -3.75 ds/-1.0 dc x 130 in the left eye .
b - scan ultrasonography showed shallow peripheral serous choroidal detachment [ fig . 2 ] .
an optical coherence tomogram ( oct - stratus version 4.0 , zeiss ophthalmics ) was also done since retinal striae were present , which showed a mild thickening of the macula .
hematological evaluation including renal parameters and computerized tomogram of the head were within normal limits .
he was reviewed after five days and his visual acuity had improved to 20/20 without any refractive error .
fundus examination revealed disappearance of retinal striae at the macula and peripheral choroidal effusion had also resolved [ figs .
a change analysis was done using the software in stratus oct version 4.0 which revealed definite reduction in the thickness of the macula .
we report a case of acute myopia induced by oral consumption of chlorthalidone for systemic hypertension .
acute transient myopia may be induced by several drugs and different mechanisms have been described .
the exact mechanism producing acute myopia is not very clear even though it has been postulated to be due to ciliary body effusion,1   peripheral uveal effusion2   and ciliary spasm3   and lens swelling .
oral sulphonamides cause transient myopia as a result of forward displacement of the lens due to allergic ciliary body edema and rotation.3,4   intravenous administration of equine anti lymphocytic globulins causes transient myopia due to ciliary spasm.7   some of the other drugs that have been described to cause transient myopia include indapamide,5   hydrochlorothiazide,2   triamterene2   and topiramate.8,9   in this case a combination of ciliary spasm and peripheral choroidal effusion explain the induced myopia . since the cycloplegic refraction showed a decrease in myopic shift by about 2 diopter it is evident that there was an element of ciliary spasm .
retinal striae have been reported to occur with acute myopia after drug intake.10   ciliary body rotation and edema resulting in forward movement of iris lens diaphragm has been reported as a possible cause for induced myopia by some authors.1,2,3,11   in this case there was no definite shallowing of the anterior chamber .
we feel that this mechanism may not explain the pathogenesis of myopia in this case . to our knowledge
since this is a common diuretic used in the treatment of systemic hypertension , we feel that it is important to be aware of this possible idiosyncratic adverse effect .
 we report a case of sudden loss of vision due to the development of acute myopia after the intake of chlorthalidone used for treating systemic hypertension . 
 clinically this was associated with ciliary spasm , shallow peripheral choroidal effusion and retinal striae at the macula with increase in macular thickness seen on optical coherence tomography . 
 all these findings were reversed completely once the drug was discontinued . 
 development of acute myopia should be kept in mind as an adverse effect of a commonly used antihypertensive drug , namely chlorthalidone . 
Case Report
Discussion