Participant-Level Inclusion Criteria

1. Participant must be 18 years of age or older.
2. Participant must understand and sign the protocol's informed consent document.
3. Female participants of childbearing potential must not be pregnant or breast-feeding, must have a negative pregnancy test at screening and must be willing to undergo monthly pregnancy tests throughout the study.

4. Female participants of childbearing potential must agree to practice two* acceptable methods of birth control throughout the course of the study and for three months after their last oral dose of finasteride. Acceptable methods of birth control include hormonal contraception (birth control pills, injected hormones or vaginal ring), intrauterine device, barrier methods with spermicide (diaphragm with spermicide, condom and spermicide) or surgical sterilization (hysterectomy, tubal ligation or vasectomy in a partner).

   *Participants with hysterectomy or vasectomy are exempt from using two methods of birth control. However female participants with a tubal ligation are not exempt and are required to practice another acceptable method of birth control.

5. Participant agrees to take the appropriate precautions to ensure that persons who are pregnant, nursing or of childbearing potential do not handle the finasteride tablets.

Participant-Level Exclusion Criteria

1. Participant is in another investigational study and actively receiving study therapy.
2. Participant is unable to comply with study procedures or follow-up visits.
3. Participant has evidence of ocular disease other than CSC in either eye that may confound the outcome of the study (e.g., diabetic retinopathy with 10 or more hemorrhages or microaneurysms, uveitis, pseudovitelliform macular degeneration, moderate/severe myopia, etc.).
4. Participant has evidence of CNV.
5. Participant has abnormal liver function testing as defined by elevated alanine aminotransferase (ALT) or aspartate aminotransferase (AST) levels that are greater than twice the respective upper limits of normal (ULN), i.e., ALT > 82 U/L and/or AST > 68 U/L. If a participant has ALT or AST levels greater than twice the ULN, the participant can be enrolled if cleared by hepatology.
6. Participant is expected to need ocular surgery during the course of the trial.
7. Participant is on steroid medication (oral, topical or inhaled).
8. Participant is on ocular or systemic medications known to be toxic to the lens, retina or optic nerve.
9. Participant has a systemic condition that, in the opinion of the investigator, would preclude participation in the study (e.g., unstable medical status including blood pressure and glycemic control).

Study Eye Inclusion Criteria

1. Eligible participants must have chronic CSC in at least one eye as defined by all of the following criteria:

   1. The presence of subretinal fluid, as determined by spectral domain OCT, AND
   2. The subretinal fluid must have been present for at least three months, or there is a recurrence of subretinal fluid within the past three months, AND
   3. The presence of characteristic fluorescein angiographic or autofluorescence features of CSC, such as one or more pinpoint leaks and/or diffuse retinal pigment epitheliopathy. This eye will be referred to as the "study eye."
2. Participant must have a steady fixation in the study eye in the foveal or parafoveal area and media clear enough for good quality photographs.
3. Participant must have visual acuity between 20/25 and 20/400 in the study eye.