Eplerenone for Central Serous Chorioretinopathy

* The goal of the study is to examine the short-term effects and safety of a systemic anti-aldosterone medication, eplerenone, in a small group of patients with central serous chorioretinopathy (CSCR).
* There is currently no standard treatment or therapy for either acute or chronic CSCR, a potentially debilitating eye disease.
* There is evidence in both animals and humans that high blood serum corticosteroid levels can cause or worsen CSCR or findings similar to CSCR in the choroid and retina
* Eplerenone, a mineralocorticoid receptor antagonist, has been shown to be of visual and anatomic benefit in a small series of 4 patients with chronic CSCR, suggesting that decreasing mineralocorticoid action in the eye may improve signs and symptoms of CSCR
* The investigators' aim is to evaluate a standardized dose of eplerenone in a controlled prospective fashion for both acute and chronic CSCR.
* The study consists of taking a standard dose of eplerenone, 50mg once daily, for 1 month
* Over the course of the month, patients will be monitored for side effects, as well as visual and anatomical response to the medication

* The investigators hypothesize that aldosterone inhibition with eplerenone will decrease choroidal vessel vasodilation, focal leakage, and choroidal thickness in patients with both acute and chronic CSCR, leading to resolution of subretinal fluid and ultimately an improvement in symptoms.
* Resolution of sub-retinal fluid will be the primary outcome, which can be precisely measured using optical coherence tomography (OCT)
* Secondary outcomes will include: Change in macular thickness measured with OCT, in central macular circle thickness on OCT, change in visual acuity, change in dye leakage characteristics on fluorescein angiography, change in OCT characteristics of the fellow eye, and safety and tolerability characteristics
* In acute CSCR, subretinal fluid often resolves on its own, but it often takes several months (the literature shows that \~20% of patients have complete resolution of sub-retinal fluid on OCT 1 month after presentation)
* Chronic CSCR is defined as persistent fluid on OCT after 3 months of symptom onset, or recurrence of signs and symptoms within 1 year after the prior episode
* In this study, the investigators will not make a distinction between acute and chronic CSCR
* Eplerenone, a generic medication, is a potassium sparing diuretic, which is FDA approved to treat heart failure as well as high blood pressure, but is not FDA approved for treatment of central serous chorioretinopathy.
* The most important side effect of eplerenone is elevation of serum potassium and decrease of blood pressure
* Patients will therefore be screened with routine blood tests as suggested by the package insert of the medication, and serum potassium and blood pressure will be monitored routinely as directed by the medication package insert
* Study visits will be performed at therapy initiation, 1 week, 2 weeks, and 4 weeks

Eligibility Criteria:
Inclusion Criteria:

1. Age 18 or over
2. Ability to give written informed consent
3. Presence of sub-retinal fluid under the fovea as seen on OCT
4. Diagnosis of Acute or Chronic CSCR:

   * Acute CSCR: First presentation to eye clinic with visual symptoms, including decreased vision or visual distortion, and the characteristic appearance of CSCR on examination, fluorescein angiography, and OCT.
   * Chronic CSCR: Previous diagnosis of CSCR, persistent subretinal fluid on OCT for more than 3 months after initial presentation to the eye clinic, and \<50% reduction in fluid thickness on OCT after 3 months. Patients who have had previous treatment for CSCR may be included.

Exclusion Criteria:

1. Age less than 18
2. Persons with impaired decision-making ability.
3. Women who are known to be pregnant or are actively trying to conceive.
4. Additional eye disease affecting the macula or posterior retina.
5. At screening, serum potassium concentration ≥5.0 mEq/L , a serum creatinine concentration \>2 mg/dL in men and \>1.8 mg/dL in women, or a creatinine clearance \<50 mL/min, and during concomitant administration of potassium supplements, potassium-sparing diuretics, and/or potent CYP3A4 inhibitors (amifostine, cyclosporine, fluconazole, itraconazole, ketoconazole, mifepristone, posaconazole, potassium salts, Rituximab, tacrolimus or voriconazole).
6. Patients with type 2 diabetes will be screened for microalbuminuria with a urinalysis. If microalbuminuria is present, these patients will be excluded.