Central Serous Chorioretinopathy

Central serous chorioretinopathy is a localized serous detachment of the neurosensory retina at the macula, caused by choroidal hyperpermeability with focal retinal pigment epithelium dysfunction. It belongs to the pachychoroid spectrum, in which the choroid is thickened and the large outer vessels are dilated.

It affects men 3 to 10 times more often than women, with peak onset at 30 to 50 years and an annual incidence of about 10 in 100,000 men. Risk factors:

• Exogenous or endogenous corticosteroid exposure by any route, including inhaled, nasal, topical and intra articular
• Cushing syndrome
• Pregnancy
• Obstructive sleep apnea
• Psychological stress and shift work
• Sympathomimetics and phosphodiesterase-5 inhibitors

It is classed as acute (under 6 months) or chronic (over 6 months, with diffuse retinal pigment epithelium decompensation). About 80 to 90% of acute episodes resolve in 3 to 4 months. Recurrence occurs in 30 to 50% within a year. Chronic disease develops in about 5%. Complications are retinal pigment epithelium atrophy, choroidal neovascularization (2 to 9%) and polypoidal choroidal vasculopathy. The bullous variant causes inferior serous retinal detachment and is seen with renal transplantation, high dose steroids and pregnancy.

• Painless central blurring, metamorphopsia, micropsia, a relative central scotoma, reduced contrast and color desaturation
• Mild hyperopic shift of 0.5 to 1.0 diopter
• Acuity usually 20/20 to 20/40
• A round, shallow detachment at the macula with a pigment epithelial detachment and yellow subretinal precipitates
• Chronic disease: gravitational tracts of atrophy and pigment mottling
• Red flags: age over 50 with hemorrhage (suggesting neovascularization), bilateral bullous detachment, unexplained systemic hypertension and hypokalemia (suggesting Cushing syndrome)

• Optical coherence tomography is first line and shows subretinal fluid, pigment epithelial detachment and a thickened choroid (subfoveal thickness over 300 micrometres) with dilated Haller layer vessels.
• Fundus autofluorescence shows hyperautofluorescence at fluid and hypoautofluorescent tracts in chronic disease.
• Fluorescein angiography shows an inkblot or smokestack leak in the early to mid phase. It is used to locate leaks before laser.
• Indocyanine green angiography shows multifocal choroidal hyperpermeability in the mid phase.
• Optical coherence tomography angiography excludes choroidal neovascularization.
• Systemic workup when indicated: medication review for steroids, blood pressure, 24 hour urinary cortisol or overnight dexamethasone suppression test, sleep study.

Differentials: neovascular age related macular degeneration, polypoidal choroidal vasculopathy, optic disc pit maculopathy, Vogt-Koyanagi-Harada disease, posterior scleritis, choroidal tumors, macular edema.

Conservative (first 3 to 4 months): stop or reduce corticosteroids in discussion with the prescriber, treat sleep apnea, limit stimulants and decongestants, and counsel on stress. Review every 4 to 6 weeks with optical coherence tomography.

Treat if fluid persists beyond 3 to 4 months, recurrences occur, acuity is falling, or occupation demands good vision:

• Photodynamic therapy with half dose verteporfin 3 mg/m2 intravenously over 10 minutes, with a 689 nm laser starting 15 minutes after infusion starts, 50 J/cm2 over 83 seconds, covering the leak and the area of choroidal hyperpermeability. Avoid direct sunlight for 48 hours. Complications: retinal pigment epithelium atrophy, choroidal ischemia, neovascularization, back pain, infusion extravasation.
• Subthreshold micropulse laser as an alternative.
• Focal thermal laser (100 micrometre spot, 0.1 second) only for leaks more than 500 micrometres from the fovea.
• Eplerenone 25 mg orally daily for 7 days, then 50 mg daily for up to 3 months, with potassium checked at 1 week and 1 month. Avoid with potassium over 5.0 mmol/L or creatinine clearance under 50 mL/min. Evidence of benefit is mixed.
• Secondary choroidal neovascularization: intravitreal aflibercept 2 mg monthly for 3 doses, then as needed.

Follow up at 4 to 6 weeks after treatment and then 3 monthly. Counsel on the recurrence risk and on early reporting of distortion.