Central serous chorioretinopathy (CSR or CSCR) is an eye disease characterized by accumulation of fluid beneath the retina. Human eye is a globe-like structure, which is divided into two compartments by the crystalline lens, known as anterior segment and posterior segment. Anterior segment of the eye is the part which we can see from outside which includes cornea, conjunctiva, sclera, iris and lens; however the posterior segment is not visible to naked eyes. Posterior segment of the eye is a 3 layered structure with a central cavity. The outermost layer is the sclera which acts as an outer protective wall followed by choroid which is the middle layer and is having surplus blood supply, the innermost layer is the retina and the central cavity is filled by gel like substance called vitreous.




CSR is primarily a disease which leads to inflammation of the choroid due to which there is leakage of fluid from the blood vessels which gets accumulated beneath the retina. There are specialized cells present between the retina and choroid known as Retinal Pigment Epithelial cells (RPE) whose main function is to pump excess fluid out of the retina and keep the retina attached and healthy. RPE has interdigitations which fit in the choroid as a key-lock system and act as a barrier between retina and choroid known as blood retinal barrier. The inflammation of choroid leads to loss of RPE interdigitations and leads to failure of blood retinal barrier leading to accumulation of serous fluid between retina and RPE leading to serous retinal detachment.



FACTORS LEADING TO CSR:

In most of the cases the cause is unknown; some cases are reported in patients with chronic steroid use. Psychosocial aspects of life also play a role such as stressful life, patients with type A personality disorders having behavioural alterations such as sense of urgency, competitive desire, go getters , short temperedness , having greater restrain, having high level of insecurities and attachments, having dependence on approval of others and higher level of anticipatory anxiety . High levels of endogenous steroids seen in physiological conditions such as pregnancy, stressful lifestyles lead to an increase in levels of cortisol in the body which can lead to CSR. It is also noted in persons having obstructive sleep apnoea which can generally be recognised as heavy snoring during sleep which leads to an increased level of catecholamines in the body leading to CSR.



DIFFERENT CLINICAL FORMS OF CSR:

It can be divided into acute form and chronic form. The distinction between the two depends upon the duration of sub retinal detachment.


Acute form is characterized by presence of sub retinal fluid, with single or multiple areas of leakage and alteration in RPE. Small areas of pigment epithelium detachment can also be seen. It usually revolves in 3-4 months leaving no or minimal residual damage.

Chronic CSR also initially known as diffuse retinal epitheliopathy is characterized by widespread tracts of RPE atrophy. Symptoms are permanent moderate to severe loss of vision. Intra retinal cystoid spaces can also be seen on long standing cases. Aggressive forms may also lead to large bullous serous retinal detachment, massive extravasations of SRF leading to accumulation of fibrin deposits or subretinal precipitates (SRP).


Recurrent CSR is said when acute CSR with SRP resolves with or without treatment and recurrence is seen at the same area or a totally new different area.



WHAT SYMPTOMS DO PATIENTS HAVE:

Patients suffering from CSR generally suffer from decrease in vision or blurred vision. Typical complaints of patients are that things appear small, known as micropsia, appearance of wavy and disfigured objects known as metamorphopsia. One might also see darkness in central vision, altered colour vision or decreased contrast sensitivity.



WHAT DOES YOUR DOCTOR SEE:

On examination of retina, presence of subretinal fluid can be seen underneath the macula, which is the most sensitive part of the retina and accounts for maximum central vision. CSR appears as a dome shaped elevated area over the macula. One or more regions of depigmented RPE is often seen, known as RPE atrophy which indicates previous lesions in retina due to CSR. In long standing chronic cases substantial atrophic changes can be seen. Sometimes long standing fluid may track down in the retina due to gravity and lead to formation of gravitational tracts.

    




INVESTIGATIONS:

Amsler grid chart- It is used to check macular function. Normally, as shown in the figure on the left, these lines appear as horizontal and vertical lines to a normal eye. In patients with CSR, these lines appear wavy or distorted or broken, as shown on the right. It is useful for detection of metamorphopsia, micropsia and also for self assessment of patients regarding progression or regression of disease.



Optical coherence tomography- shows an optically clear neurosensory detachment. It can also show small RPE detachments. Degenerative changes occurring in chronic and recurrent cases can also be seen.


Here in this image, we can see the OCT pre and post treatment.




Fluorescein Angiography- It’s an imaging modality in which fluorescein dye is injected from the arm and retinal photographs are taken. It shows a hyper fluorescent spot which gradually increases which is also known as ink blot appearance or less commonly a vertical column with diffusion of dye through detached retina known as smoke stack appearance. Multiple areas of leak can be evident in chronic and recurrent CSR.


Other tests can be ICGA and OCTA, which can be useful in select cases.



MANAGEMENT:

In management of CSR patients, counselling is the chief task to be done. Patients should be explained that it is a self resolving condition in 80% cases and takes about 1-3 months. Patients need to understand that in the majority of cases the underlying cause has to be treated such as complete stoppage of steroids intake in any form. Smoking is an integral factor, and complete cessation can aid in faster resolution of the disease. Lifestyle changes need to be done in which stress management is the main focusing element; hence yoga, meditation and psychotherapy are recommended. These patients usually have financial, social or emotional problems, which need to be thoroughly dealt with. CSR can also be caused by certain drugs, so looking into the drug history and having a word with the patient’s physician can often help. It’s imperative to explain to the patient that nearly half of the patients can have recurrence if the instigating factors are not curbed, and hence follow up is required as advised.

Active management strategies include use of retinal lasers to stop leakage of fluid. The laser acts as a seal, and blocks the area which is leaking. The laser is done based on the leak seen on the angiography. Once the laser is done, it takes around 1-3 months for the fluid to resolve as shown in the figure. Sometimes, a new leak can occur at a different spot, so multiple sitting of laser may be needed. The amount of fluid post laser can be easily monitored by an OCT scan.

If the leak is involving the fovea, a micropulse yellow laser or a Photodynamic therapy with verteporfin dye can be used. Active management is required when serous detachment of retina stays for more than 3 months, in case with recurrence, permanent visual defect in fellow eye, occupation of patient and appearance of signs of chronic CSR such as RPE atrophy and intraretinal fluid. At times, there can be an active membrane that can be seen along with the CSR, which might need intravitreal injection of Anti VEGF. Other less common treatment modalities include use of alpha-adrenergic blockers, beta-adrenergic blockers, or corticosteroids antagonists.


AUTHORS:

Dr Dhaivat Shah (MS DNB FMRF) (Vitreoretinal Surgeon)

Dr Rahul Singh (DOMS) (DNB Asp)

For any queries related to this topic, kindly mail on: dhaivatkshah@gmail.com