Central Serous Retinopathy (CSR)

 OVERVIEW

CSR occurs when a small break forms in the outer pigmented layer of the retina.  Clear fluid from the layer of blood vessels that lie underneath the retina seeps up through the break, causing a small detachment to form under the retina. 

This problem is somewhat similar to a water blister that forms on the skin.  The process is similar to CSR:  fluid collects beneath the skin's surface, causing the layers of skin to separate.

The retinal pigment epithelium is a single-celled layer that lies between the retina and the choroids. This tissue layer normally serves to prevent fluid from the choroidal circulation from leaking under the retina. In central serous, fluid equilibrium is disturbed leading to leakage beneath the retina which elevates it to produce a macular detachment which distorts vision.

Central serous retinopathy is a slight accumulation of fluid in the macular (center of the retina) region of the eye that lies between the retinal pigment epithelium (the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells) and the outer segments. A relative central scotoma (area of lost or depressed vision within the visual field surrounded by an area of less depressed or normal vision) results, but usually resolves spontaneously within a few months. Serous means thin and watery-like serum. Central serous retinopathy is characterized by an accumulation of transparent fluid at the posterior pole of the fundus (base), causing a circumscribed area of retinal detachment at the posterior pole. When left alone, central serous retinopathy heals spontaneously within 6 months (average 3-4 months), with full recovery of visual acuity. However, about one-third to one-half of all patients have recurrences after the first episode of the disease; 10 percent have three or more recurrences. In almost half of the patients, the recurrence is within one year of the primary episode, but relapses may occur up to ten years later.

Causes and Risk Factors: 
The disease primarily affects young adults ages 20 to 45. Men are affected ten times frequently than women.  CSR is sometimes calledidiopathic CSR which means that its cause is unknown. Nevertheless, stress appears to play an important role. An oft-cited but potentially inaccurate conclusion is that persons in stressful occupations, such as airplane pilots, have a higher incidence of CSR. The "type A personality" has also been linked to this condition. However, the statistics may be skewed by the fact that CSR often goes undiagnosed or misdiagnosed; airline pilots and so-called "type A" people are demonstrably exacting, demanding people with (certainly in the case of pilots) better-than-average vision. They are more likely than the general population to notice the sometimes-subtle degradation of vision caused by CSR and insist on a believable diagnosis of it. People who need glasses may assume that the blurriness caused by CSR is simply a change in their prescription, and fail to have the condition assessed by a retinal specialist. These statistic-skewing factors undermine the conclusion that CSR is a condition specific to "type A" people.

CSR has also been associated with cortisol and corticosteroids, and persons with higher levels of cortisol than normal also have a higher propensity to suffer from CSR. Cortisol is a hormone secreted by the adrenal cortex which allows the body to deal with stress, which may explain the CSR-stress association. There is extensive evidence to the effect that corticosteroids ("cortisone") --- commonly used to treat inflamations, allergies, skin conditions and even certain eye conditions --- can trigger CSR, aggravate it and cause relapses.

The incidence of CSR in persons with Cushing's syndrome 5%. Cushing's syndrome is characterized by very high cortisol levels.

SIGNS AND SYMPTOMS

Many patients first notice a minor blurring of vision, followed by various degrees of:

  metamorphopsia (defective, distorted vision)

  micropsia (distorted visual perception in which objects appear smaller than their actual size)

  chromatopsia (visual defect in which objects appear unnaturally colored)

  central scotoma

  increasing hyperopia (farsightedness)

Visual acuity in the acute stage may range from 20/20 to 20/200 and averages 20/30. In some patients the onset of symptoms is preceded or accompanied by migraine-like headaches.

DIAGNOSIS:

The diagnosis usually starts with a dilated examination of the retina, followed with confirmation by OCT and or fluorescein angiography. The angiography test will usually show one or more fluorescent spots with fluid leakage. In 10%-15% of the cases these will appear in a "classic" smoke stack shape. An Amsler grid may be useful in documenting the precise area of the visual field involved.
 

Prognosis: Most patients with central serous retinopathy will spontaneously recover visual acuity in six months (average time to recovery three to four months). Many patients will have some residual symptoms, such as distortion, decreased color and contrast sensitivity, and visual difficulty at night. Despite an overall good prognosis, 40 to 50 percent of patients experience at least one recurrence.

 

TREATMENT:

 Although no medication has thus far proved effective in treating central serous retinopathy, a beneficial effect of laser photocoagulation has been reported in several studies. Findings indicate that direct photocoagulation of the leakage point not only shortens the acute phase of the disease but also lowers the recurrence rate to about one fifth of what would be expected without active treatment.

If possible, any ongoing corticosteroid treatment including nasal sprays, skin creams, inhalers and oral medications should be stopped.