Idiopathic polypoidal choroidal vasculopathy IPCV (also called posterior uveal bleeding syndrome), is a rare condition characterised by:

• A juxta-papillary, (macular or peripheral) branching choroidal vascular network with surrounding polypoidal aneurysmal dilatation.
• Recurrent, multiple, and bilateral serous and haemorrhagic detachment of the neuro-sensory retina and the RPE.
• No macular drusen or intraocular inflammation.

The condition is commoner in females and may be associated with systemic hypertension. Optical coherence tomographic images show that some of the polypoidal structures are anteriorly protruding lesions in the inner choroid. These lesions may cause detachment of the retinal pigment epithelium. Sub-macular haemorrhage may also occur in some patients. The differential diagnosis of this condition includes various causes of choroidal neovascular membrane.

The macular variant of this disease is characterised by recurrent subretinal haemorrhage and exudates. It can be distinguished from other causes of macular choroidal neovascular membrane by indocyanine green or fluorescein angiography. Fluorescein and indocyanine angiography often shows the choroidal vascular network and RPE detachment.

Laser photocoagulation may be used in cases with subretinal exudate or fluid. Surgical excision of the subretinal membrane may be beneficial in eyes with sub-macular haemorrhage associated with idiopathic polypoidal choroidal vasculopathy.

Histological studies of removed tissues demonstrated fibrovascular tissue between the retina and retinal pigment epithelium (type 2 pattern). Visual prognosis is good, but vitreous haemorrhage and choroidal neovascular membrane may lead to visual deterioration in some patients.

Photodynamic treatment is a new method for selective treatment of subfoveal choroidal neovascularisation. The technique causes occlusion of the neovascular tissue with minimal damage to the healthy surrounding structures. This mode of treatment involves intravenous injection of a photo-sensitiser dye, followed by irradiation of the photosensitized tissue by a suitable light.

Photodynamic therapy has been applied successfully for experimental treatment of tumours as well as for photo-thrombosis therapy for normal and abnormal blood vessels. It is generally accepted that the dye binds to the endothelium lining of the choroidal neovascular membrane. Light induced activation of the dye generates oxygen radicals which would then starts a clotting mechanism inside these abnormal vessels. Release of free radicals from the sensitized tissue also leads to structural damage of cell membranes and cell death.

A liposomal preparation of benzoporphyrin derivative (Verteporfin) have been shown to be safe and effective for use in the treatment of choroidal neovascular membrane since the dye can easily be taken by the growing vessels. Effective occlusion of normal choroidal vessels can also be achieved by using the new photo-sensitiser NPe6, with minimal injury to overlying neuro-sensory retina. Both NPe6 and the benzoporphyrin have a strong far-red absorption and rapid skin clearance, but NPe6 differs from the benzoporphyrin in that it is hydrophilic and can be available in aqueous preparation.

Post-treatment fluorescein angiography shows significant reduction in the filling of the choroidal neovascular membrane and also reduction of the late phase leaking. An area of choroidal hypo-fluorescence is also noticed for about one week after treatment.

A new hypothesis has been put forward to explain few of the clinical and angiographic features of treatment that can not be explained by the traditional hypothesis. It is thought that light activation of the dye would lead to liberation of oxygen radicals, which act on the red blood cells, first of all, to liberate haemoglobin which has a vasoconstriction effect. Flow reduction to the treated area may be due to vasoconstriction of the vessels, followed by clotting of the slowed down blood.

A recent non-randomised, multicentre, open-label, clinical trial showed that photodynamic therapy achieves short-term cessation of fluorescein leakage from choroidal neovascular membrane without loss of vision or growth of classic choroidal neovascular membrane in some patients after a single treatment. Non-perfusion of neuro-sensory retinal vessels at high light dose (150 J/cm²) may occur in some patients. Fluorescein leakage from at least a portion of the membrane reappears by 4 to 12 weeks after treatment in almost all cases.

Multiple laser treatments appear to achieve repetitive, short-term cessation of fluorescein leakage without loss of visual acuity. Animal studies showed that repeated applications are associated with limited damage to the retina when using 6-mg/ m² Verteporfin. High doses of the dye may, however, be associated with significant damage to the retina, choroid and the optic nerve.

The 12-month results of this treatment were recently reported in a multicentre, double-masked, placebo-controlled, randomised clinical trial. 61% of treated eyes, lost fewer than 15 letters of visual acuity, from baseline, compared with 46% of untreated at the end of a 12 months period examination. The visual results of the study were strikingly better in eyes with predominantly classic choroidal neovascular membrane (classic choroidal neovascular membrane was defined as a membrane with a classic component that is equal to or greater than 50% of the area of the entire lesion). There was no difference in visual outcome in patients demonstrating less than 50% classic choroidal neovascular membrane at the initial visit. The protocol of treatment that was used in this trial includes:

 Possible adverse effects of the treatment include:

1. Transient visual disturbances
2. Injection-site adverse events
3. Transient photosensitivity reactions
4. Infusion-related low back pain.

Trans-pupillary thermotherapy may provide an alternative method of treatment for subfoveal choroidal neovascular membrane. The technique has been used successfully in treating choroidal malignant melanoma. In this technique, heat is delivered to the choroid and retinal pigment epithelium with a modified diode laser. Near infrared radiation is ideal for this technique as tissue penetration is high and absorption by the ocular media is minimal. Thermal treatment for choroidal neovascular membrane needs less choroidal tumours, and damage to the surrounding retina is, thus, expected to be small. Earlier studies showed no significant side effects from this method of treatment.

The Implantable Miniaturised Telescope (IMT) is a new approach to aide vision in patients with dry age related maculopathy. The telescope consists of a 3X telescope that is contained in carrying device made of PMMA that can be implanted in the capsule bag under local anaesthesia. The IMP provides improvement of the central visual acuity in the implanted eye for reading, while the other eye can be used for peripheral navigational vision. The implant has a universal power, fine adjustment of vision can be achieved by wearing low power plus or minus spectacles. 91% of patients tried with this device reported improvement in viewing television, and 66% reported improvement in reading vision. The advantages of the implant is that it provides magnification of vision without the need to hold the device by hand, which avoid the relative movements between the eye and the hand. Some patients may notice transient postoperative difficulty in orientation.

Determining the genetic locus of the disease and targeting it may provide an effective way of treatment. Studies are currently underway to investigate the relationship of age related maculopathy and the ABCR gene, which code for the retinal photoreceptors, and which has been found to be altered in patients with Stargardt’s disease.