What does it involve?
This treatment involves destroying the intraocular tumours from the ocular surface without invading the eyeball. In principle, the scleral surgery technique is used primarily in melanin-type tumours, such as choroidal melanomas and, in some cases, vascular or metastatic tumours. The technique involves using, in most cases, a radioactive ruthenium-106, or sometimes an iodine-125, plaque. These plaques are placed on the surface of the eye, adjacent to the tumour.
When is it carried out?
The tumours that are treated in most cases are choroidal melanomas and metastatic and vascular tumours.
Prior to treating the tumour, it is very important to know the diagnosis as well as whether the tumour has spread to the rest of the body, or if the tumour is the metastasis of a primary tumour in another location. It is, therefore, essential to perform a full-body PET-CT screening test to detect for tumours that are larger than 5 mm in all organs of the body. It is also possible to carry out blood tests to assess the functioning of some organs and check for primary tumours.
Before the surgery
The most important precaution to take is to prevent tumour spread, and, to do so, it is essential to perform the technique with a microscope, as it is very delicate, and to have a good knowledge of the anatomy of the eyeball.
The procedure is performed under local anaesthesia and involves dissecting the outer layer of the eyeball, the conjunctiva, and Tenon’s capsule to enable access to the sclera, the white wall of the eyeball. It is in the sclera that the radioactive plaque is placed after locating the tumour. The tumour is located by means of a magnifying glass for examining the fundus or transillumination, in which the pigmented nature of choroidal melanomas produce a very opaque transillumination in contrast to the white wall of the eyeball. In some cases, it is also necessary to apply other scleral techniques, such as the implantation of silicone rings, to release tension on the retina caused by tumours, laser photocoagulation or trans-scleral cryotherapy.
The main risk is tumour spread, but other risks include haemorrhaging in the vitreous cavity, retinal detachment and infections, although they are much less common.