NLP status after open-globe injury not always permanent

November 11, 2017

Management of patients with loss of light perception after open-globe injury has historically been to observe or enucleate the eye with the goal of reducing the risk of sympathetic ophthalmia. Existing data, however, support rethinking that paradigm and instead considering surgery for carefully selected patients who have a chance for recovering vision.

Management of patients with loss of light perception after open-globe injury has historically been to observe or enucleate the eye with the goal of reducing the risk of sympathetic ophthalmia.

Existing data, however, support rethinking that paradigm and instead considering surgery for carefully selected patients who have a chance for recovering vision.

“Loss of light perception after open-globe injury does not necessarily mean the patient will have permanent visual loss,” said Marco A. Zarbin, MD, PhD, speaking at the 2017 Retina Subspecialty Day meeting.

In fact, published results show that the rate of visual recovery from no light perception (NLP) to LP or better in these cases ranges from 4% to 35%. While the level of vision recovered in these cases is usually very poor, there are some well documented cases showing that it can be remarkably good, he noted.

 

“In our series of 73 NLP eyes with open-globe injury that underwent primary repair, 17 (23%) recovered some degree of vision and 4% recovered ambulatory vision,” said Dr. Zarbin, the Alfonse Cinotti, MD/Lions Eye Research Professor and Chair, Institute of Ophthalmology and Visual Science, Rutgers-New Jersey Medical School, Newark, NJ.

“Furthermore, the incidence of sympathetic ophthalmia in these cases in the modern era is only about 0.2%,” he said. “While this risk may increase after operating on the injured eye, it remains less than 1%.”

He outlined an approach for surgical decision making in cases of NLP eyes with open-globe injury. Rather than focusing on psychophysical findings, the evaluation aims to determine what anatomic findings underlie the NLP status.

“This approach makes sense considering the difficulties of accurately assessing light perception status in trauma patients who are often intoxicated, unconscious, or children,” Dr. Zarbin said.

“Even more objective tests, like electroretinography, can give a falsely negative result,” he said.

“In contrast, some anatomic findings are consistent with irreversible loss of vision whereas others are amenable to surgical repair.”

The anatomic findings that are associated with permanent NLP status include optic nerve avulsion, optic nerve transection, and profound loss of intraocular contents.

Using some case examples, however, Dr. Zarbin demonstrated that CT/MRI imaging can be needed to reliably identify optic nerve avulsion/transection in the setting of severe globe trauma. Even using these techniques, he encouraged consultation with a neuro-ophthalmology colleague.

“If you think the optic nerve is transected or avulsed, it is prudent to ask a neuro-ophthalmologist to look at the scan,” Dr. Zarbin said.

Potentially treatable causes for NLP status include retinal detachment with dense vitreous hemorrhage, retinal detachment with subretinal hemorrhage, and suprachoroidal hemorrhage. All of those findings are best seen using B-scan echography.

 

Sequential surgery

If the decision is made to perform surgery that might restore vision, Dr. Zarbin recommended using a staged approach, beginning with the open-globe repair and then waiting 1 to 2 weeks before undertaking the second procedure.

The delayed timing for the second procedure improves the chances of anatomic and function success because it allows for liquefaction of suprachoroidal blood and healing of the primary wounds to create a watertight compartment in which to operate.

In addition, it minimizes the amount of intraoperative bleeding encountered, Dr. Zarbin said.

The techniques that will be performed in the second procedure depend on the injuries present. The procedure may involve placement of a keratoprosthesis, drainage of suprachoroidal hemorrhage, removal of any residual lens and foreign material, and excision of vitreous hemorrhage and subretinal hemorrhage.

“However, in cases with posterior disruption of the eye wall, subretinal fibrotic tissue is almost always present if the retina is detached,” Dr. Zarbin said. “Subretinal fibrosis, particularly if in a napkin ring configuration, can prevent retinal re-attachment and should be dissected aggressively. Typically, this step involves using a 360° retinotomy to create good access to the subretinal space and bimanual dissection facilitated by chandelier illumination.”

 

He reported that in his group’s series of 73 NLP eyes that underwent primary repair, 15 eyes underwent PPV, and they were found to be significantly more likely to achieve LP or better final vision than eyes that did not have PPV.
“The 17 eyes in our series that had final vision of LP or better included 14 (93%) of the 15 eyes that underwent PPV,” Dr. Zarbin said.

“That is not to say that vitrectomy will cure NLP vision, however, considering that we operated on eyes that we thought had a chance of recovery,” he said. “Rather we turned out to be right in judging vision to be salvageable about 80% of the time.”

An interesting finding in Dr. Zarbin’s series was that 62% of eyes that recovered LP vision on the first day after primary repair had final vision of LP or better after additional surgery. Of the eyes that remained NLP on postoperative day 1, only 8% recovered to LP or better vision.

“Eight percent is not zero, but remaining NLP on the day after primary repair seems to be a negative prognostic finding,” Dr. Zarbin said.

He noted, however, it will be important for other researchers to confirm the finding that sensory status on the day after primary repair has prognostic value.

 

Additional evaluation and counseling considerations

Dr. Zarbin advocated for having the attending surgeon confirm the vision assessment in patients with open-globe injuries and NLP rather than relying solely of the resident or fellow’s assessment.

“It is a bit of an art to check the vision in this setting, and so it should be done by an experienced examiner and using the indirect ophthalmoscope set to maximum intensity, not with a penlight,” he said.

He also said that patient selection for surgery goes beyond anatomic considerations.

“In addition to what is going on in the eye, we have to try to figure out what is going on in the person’s head,” Dr. Zarbin explained.

“We typically tell patients that there is about a 5% chance they will recover ambulatory vision after surgery, and we also discuss the risk of sympathetic ophthalmia with and without additional surgery,” he said. “But some people who are told they have a 5% chance of recovering vision hear that the chance is 95%, and we will not operate on anyone who has such unrealistic expectations.”