Since the 1990s, diode laser transpupillary thermotherapy (TTT) has been an adjuvant to radiation therapy for patients with uveal melanoma (UM) to help facilitate tumor consolidation. Though successful in promoting tumor regression, TTT may result in the creation of atrophic retinal holes and subsequent retinal breaks or detachments in 1% to 13% of cases, so it wouldn’t be unusual for a UM patient who had been treated with TTT to present in a retina specialist’s office today with this problem.

Management of such a patient should be undertaken in collaboration with an ocular oncologist or experienced retina specialist who can evaluate the status of the tumor to ensure it is inactive and that repair of the retinal detachment can be safely accomplished. The preoperative discussion with the patient must be thorough, with the surgeon balancing defined surgical goals: to safely reattach the retina, avoid phthisis to maintain ability to monitor the tumor status, and to maximize visual potential. In general, if a UM eye develops a detachment shortly after treatment, I typically wait to address the detachment until I can confirm the tumor is regressing and unlikely to reactivate. However, the decision to delay retina detachment repair must be balanced in each case against the resulting chronicity and its potential impact on visual prognosis, especially if the macula is involved.

Preoperative Considerations

If the decision is made to proceed with surgery to fix a retinal detachment in an eye previously treated for melanoma, certain factors should be taken into account preoperatively.

First, know everything about the particular tumor and prior treatments. It is important to determine, by way of clinical exam and ultrasound, the current size and location of the tumor to avoid making surgical wounds directly into or immediately adjacent to the tumor site. Further, if the UM is large, pedunculated, or is a diffuse lesion, one must consider instrument entry sites that avoid inadvertent contact with the tumor during surgery. Be aware that in some cases, melanomas that are positioned anteriorly may cover the peripheral choroid, pars plana, or ciliary body, which are common locations for sclerotomies; ultrasound biomicroscopy is invaluable in identifying the extent of such tumors. The surgeon may need to adjust the location of some or all sclerotomy sites to avoid piercing through the tumor and creating a tract that would allow UM cells to exit the eye.

A second preoperative consideration is to identify signs of proliferative vitreoretinopathy (PVR), which may be present due to the often long-standing nature of these detachments. The presence of PVR may alter the surgical approach and, specifically, whether to place a scleral buckle at the time of surgery. I prefer to do so to support the vitreous base as I have found these cases often have peripheral vitreous base contraction in the absence of star folds. Keep in mind these eyes may have conjunctival or muscle scarring from prior brachytherapy plaque placement or choroidal biopsy, so dissection planes may be challenging.

Similarities and Differences Compared with Surgery in Non-Melanoma Eyes

The principles of retinal detachment repair, even in eyes with a treated UM, are no different than other cases: identify the retinal break, release all vitreoretinal traction, seal the break, and consider long-acting tamponade. When possible, I prefer to leave the crystalline lens in place if visualization can be maintained during the surgery.

There are some differences in these treated UM eyes, which need to be considered. A posterior vitreous detachment is not always present in these eyes and the retinal defects are usually atrophic holes associated with the TTT scar with very thin retina overlying the main tumor. Posterior hyaloid separation will need to be induced carefully to avoid iatrogenically enlarging existing breaks or creating new breaks while removing the hyaloid. I often use bimanual technique while highlighting the vitreous with steroid to detach the hyaloid in a controlled manner. Sometimes, I use perfluorocarbon liquid (PFCL) posteriorly, as a “third hand” to support the retina while I peel anteriorly over the existing breaks or detachment. PVR membranes are identified and removed but I do not routinely perform internal limiting membrane removal. Scleral depression-assisted peripheral shaving is performed routinely.

Laser treatment is applied to the retinal break and, depending on the size and appearance of the tumor, I may also confluently “paint” over its surface with the laser. This has the benefit of further consolidating the tumor and may reduce the risk of secondary inflammation from “toxic tumor syndrome.” Silicone oil is a very effective tamponade in these eyes, especially if there are signs of PVR, but I will try to consider the use of a long-acting gas, such as C3F8, mainly to avoid a secondary oil removal procedure.

I find that 23- and 25-gauge instrumentation both work well in these cases, but in my opinion, a more important consideration than gauge is having the availability of instruments for bimanual technique when they’re needed. Any modern vitrectomy system should be suitable for tackling this type of case. I tend to use the Constellation Vision System (Alcon), which offers smooth fluidics, valved cannulas, and the ability to control the shaving of the peripheral vitreous, which I find to be important in repairing detachments in the presence of treated ocular melanoma. It supports the goal of removing the vitreous as thoroughly as possible, leaving the least potential for residual vitreous that could eventually contract and cause redetachment. The system’s shave mode enhances the control I have by enabling a high cut rate with relatively lower maximum suction and the cutter port biased open. It’s beneficial to have such responsive aspiration control in light of the very thin retina that tends to overlie the tumor and areas of prior TTT treatment. I can work very close to the retinal surface without concern that retinal tissue will jump into the cutter port.

Special Precautions

During retinal detachment repair in eyes with treated melanoma, it’s important to minimize any contact or direct instrument interaction with the tumor. The surgeon should also try to minimize fluid egress from the eye, which is minimized with the use of valved cannulas, to prevent the potential for migration of tumor cells from inside the eye into the subconjunctival space.

I always suture the sclerotomies in these eyes, even if they’re not leaking, to ensure I have closed the access of potential tumor cells from exiting the eye after surgery. I also apply external cryotherapy in a double freeze-thaw pattern over the sutured sclerotomy wounds so any atypical or tumor cells that may have been tracking out of the eye on an instrument or cannula aren’t deposited in the subconjunctival space. These are conservative measures with very little downside but may help to avoid potential complications in the future

Postoperative follow-up for UM eyes with retinal detachment repair is no different than a non-UM eye, with the exception of careful follow up of the tumor status with an ocular oncologist. Finally, these eyes tend to develop secondary cataract in time. I’m relatively conservative when it comes to recommending removal. Given what the eyes have already gone through, I don’t see it as a priority, especially if the fellow eye sees well.

An Illustrative Case

One of my patients, a 69-year-old female, was treated with plaque brachytherapy and one session of TTT for a peripapillary melanoma in the left eye. The tumor showed excellent response with reduction in tumor size, but there was persistent subretinal fluid tracking inferior to the lesion. It was initially unclear if the subretinal fluid was due to slow reabsorption of prior subretinal fluid, continued fluid exudation from the tumor, or related to a rhegmatogenous component we could not readily identify. By 18 months, the tumor remained regressed, and it became evident that an atrophic break in the region of prior TTT treatment had resulted in a rhegmatogenous retinal detachment.

Within weeks of discovery of the detachment, surgery to repair it was scheduled (Figure 1). I placed a scleral buckle at the beginning of the procedure. The hyaloid was attached, making vitreous separation difficult. In addition, the break was posterior and involved significant bullous anterior fluid, which can make complete hyaloid peeling to the periphery more challenging. To address these factors and avoid creating new breaks in the retina, I used PFCL to stabilize the posterior retina, and I used a lighted pick and forceps to bimanually peel the hyaloid and remove all anterior PVR membranes. After applying laser to the detached area, I used C3F8 for tamponade.

The patient is now close to 2 years post surgery. While the eye is exhibiting signs of radiation retinopathy, visual acuity is excellent at 20/25, the tumor remains inactive, and the retina remains attached. ■

Dr. Mruthyunjaya is associate professor of ophthalmology and a member of the Vitreoretinal Surgery Service at Stanford University as well as the director of Ocular Oncology at the university’s Byers Eye Institute in Palo Alto, Calif. He can be reached at prithvi9@stanford.edu.