“Ask your treating surgeon what is the aim of treatment and how many patients they have treated with this condition to get a sense of their personal expertise in this area”
Treatment of CSR
Treatment of CSR is generally reserved for the following circumstances;
- Where the CSR has not fully resolved by six months or has not shown a trend towards resolution by four months
- Where the vision is showing signs of declining during those first few months of observation
- Where previous episodes have tended to last much more than 4-6 months,
- Where a patients occupation or lifestyle are significantly affected by the symptoms of CSR,
- Where other medical factors are likely to prolong the course of the condition (e.g corticosteroid, use that cannot be reduced or eliminated),
- Where a patient feels that waiting for up-to six months to allow natural recovery could adversely affect their general well-being,
- Where both eyes are affected simultaneously
The major aim of any treatment option being administered in cases of CSR is to cause a resolution of the CSR episode. Successful treatment of CSR may help to ‘stabilise’ vision which would otherwise continue to deteriorate. Its also possible that treatment may help to lower the chances of a patients CSR progressing to the more damaging types of CSR – chronic CSR and sick RPE syndrome CSR.
- A secondary aim may be to help reduce the level of distortion experienced by the patient.
- Finally although it is quite possible to see cases of significant vision improvement in CSR treatments this is not the normal experience of patients who do undergo treatment.
- Treatment Options for CSR
There are two widely accepted forms of treatment for CSR that can fulfil at least one of the above criteria. Both forms of treatment involve a laser procedure. In simple terms we can describe these treatments in terms of the type of laser used.
High energy or ‘Hot’ laser is where a laser similar to that used for treating diabetic eye disease – called Argon Laser is used to treat the CSR. Conversely low energy or ‘cold’ laser is where a laser is used in conjunction with a special dye to treat the CSR.
- Thermal Energy Laser with Argon Laser Photocoagulation
For this treatment to be applicable we must be able to identify one or more specific areas of activity on the macula and for them to be far enough away from the very central part of the macula (called the fovea) to make it safe for this form of treatment. Areas of activity are usually identified by carrying out an investigation called fluorescein angiography (FFA). In cases where the surgeon is able to clearly identify an active area – sometimes referred to as ‘hot spot’ then treatment with argon laser can help to ‘seal off’ the hot spot thus helping to resolve the CSR episode.
As the laser beam used is one of high power (hot) the effect of argon laser in this context is one of very small areas of controlled cauterisation. This is why active areas that are too close to the very central part of the macula are not suited to this form of treatment. Our experience is that argon laser is useful in less than one third of all CSR cases but where appropriate it can be incredibly effective.
- Risks of Argon Laser Photocoagulation
Although generally a safe form of treatment potential risks of argon laser are
Inadvertent damage to the central part of the macula this can result in reduced eyesight,
The likely production of a permanent ‘dark spot’ - also called a scotoma in the vision close to the centre of vision. This issue should be discussed carefully before the treatment is administered,
Sometimes either the laser treatment or the CSR condition itself can develop into a type of wet macular degeneration. This can happen weeks or years down the line and would require treatment as for wet macular degeneration.
- Non Thermal Laser - Photodynamic therapy with Visudyne
Also referred to as PDT for short this treatment was until a few years ago the benchmark treatment for wet AMD. The advent of the injection treatments for wet AMD superseded PDT but it now has an established role in helping treat CSR. In PDT the energy level of the laser is very low and thus there is no ‘cauterisation’ effect. Rather PDT works in conjunction with a special dye called Visudyne (Verteporfin) which is given as an intra-venous injection a few minutes before application of the laser.
The area of laser administration onto the macula will depend on the extent of activity identified either on a fluorescein angiogram and or on a indocyanine green angiogram (ICG). The concept is to cover the whole area of the macula that is active with CSR. The low energy laser interacts with the injected dye to produce an biological effect that helps to cause a resolution of the CSR in the vast majority of treated cases.
Our own experience is that PDT can be incredibly effective and allows treatment of CSR cases that hitherto would not have been treatable by the traditional argon laser method.
- Example Case Study of PDT applied in CSR
An example of a patient suffering from chronic sick rpe syndrome CSR with very poor eyesight. In this case the vision was at the legal level for severe sight impairment. The CSR had been present for many years and had been exacerbated by long term
use of steroid medication. Despite a cautious treatment outlook we found a strong positive response to a single dose of PDT.
Treatment resulted in rapid resolution of the fluid under the macula and eyesight improved by over 3 lines on a standard vision chart. Most impressively in this case the effect of the treatment had lasted for well over two years at last follow when the latest OCT scan was taken.
- Risks of PDT Laser
Our experience of PDT laser for CSR is that it is generally very safe and effective but as with any treatment option there are potential risks as follows:
The treatment may not be effective in which case there is potential for a second treatment to be considered – normally after a minimum wait of three months.
In around 1-2% of cases there is a potential for significant vision decline to occur shortly after PDT administration. Although this adverse effect can be permanent our local experience is that the vision does often recover over time. This reaction is unpredictable and should be carefully discussed prior to the treatment.
As with argon laser based treatments for CSR there is a potential for later conversion of CSR into a form of wet AMD – this can occur weeks or years down the line and would require standard treatment as for wet AMD.
- Other treatments for CSR
In addition to the two most widely recognised forms of treatment for CSR there are also other options that could potentially be considered for managing CSR:
Bevacizumab (Avastin) eye injections – anti VEGF therapy – a similar injection to that used for wet macular degeneration has been reported to have a positive impact on certain types of CSR.
Ketoconazole. This antifungal antibiotic is also thought to have anti-steroid properties and there are some reports of a positive impact on CSR.
Mifepristone. This drug is also thought to have anti-steroid properties and may be able to play a role in managing some forms of CSR.
In general most cases of CSR will not require treatment but where treatment is thought to be considered beneficial the two major options for CSR treatment are highly effective and also quite safe. Patients with CSR require expert diagnosis and treatment and a careful and thorough discussion of the individual risks and benefits in their case.