Cataract Surgery May Not Restore Vision | When Shingles Damages the Retina
Shingles, caused by reactivation of the varicella-zoster virus, can sometimes affect the eye in a much more serious way than causing a rash or corneal inflammation. In severe cases, the virus can cause intense inflammation inside the eye, known as vitritis, and may progress to acute retinal necrosis (ARN). Once retinal necrosis develops, the visual prognosis can become very guarded.
Recently, I encountered a challenging case illustrating an important point that every patient should understand before undergoing surgery in an eye affected by severe viral retinal disease.
A Challenging Case
The patient developed shingles-related intraocular inflammation followed by retinal necrosis. Despite treatment, the retina had already sustained significant damage. The eye subsequently developed cataract and required major vitreoretinal surgery. Cataract surgery was performed as part of the surgical management, together with vitrectomy and silicone oil tamponade to stabilize the retina.
The important message is that removing a cataract does not repair a retina that has already been destroyed by necrosis.
What Surgery Can and Cannot Achieve
In such situations, the purpose of surgery may be to preserve the anatomical integrity of the eye, prevent or repair retinal detachment, clear severe vitreous changes, and, where possible, preserve whatever useful vision remains. Silicone oil is frequently used when retinal detachment or significant retinal instability is present. However, the final visual outcome depends heavily on how much damage has already occurred to the retina and optic nerve.
Unfortunately, in this particular case, the final vision remained at perception of light (PL). The patient also required long-term management of an eye containing silicone oil.
Informed Consent Matters
This is an important lesson in informed consent. A patient should understand before surgery that the objective may not be to restore normal vision. In a severely damaged eye, surgery may instead be an attempt to save the eye anatomically, prevent further complications, or retain the limited vision that remains.
Silicone oil itself can also create a long-term management issue. Depending on the condition of the retina and the risk of recurrent retinal detachment, the oil may sometimes be removed later, while in other eyes it may need to remain for a prolonged period or indefinitely. Studies of acute retinal necrosis complicated by retinal detachment have shown that silicone oil cannot always be safely removed.
Why Timing of Treatment Is Critical
The timing of treatment is therefore extremely important. When viral retinitis is suspected, early antiviral treatment and close retinal monitoring are essential. Once extensive retinal necrosis has developed, treatment becomes considerably more difficult, and retinal detachment and proliferative vitreoretinopathy can further compromise vision.
The key message for patients is simple: cataract surgery can remove a cloudy lens, but it cannot reverse retinal tissue that has already been destroyed by viral necrosis.
Final Thoughts
Therefore, before cataract or vitreoretinal surgery in an eye affected by severe shingles-related retinal disease, patients should have a clear discussion about the realistic visual prognosis, the possibility of retinal surgery, silicone oil, additional procedures, long-term follow-up, and the possibility that useful vision may not return despite technically successful surgery.
In each case the doctor should make sure what are the objectives or the surgery. Patient should understand the clinical picture and be realistic about the outcome.