Ocular trauma treatment becoming a more sophisticated science

Ocular trauma may be increasing, but advances in technology are helping surgeons treat the conditions more successfully.

ROME – The incidence of eye injuries during military operations has increased exponentially in recent decades, according to a collection of data presented at the International Society of Ocular Trauma meeting.

Compared with World War I and World War II, more recent conflicts, such as the Gulf and Croatian wars, reported five to six times the number of ocular injuries. Statistically, the eye is one of the most frequent targets of wartime injuries, one speaker here said.

“Provided that the profile surface of the eyeball constitutes only 0.1% of the frontal body silhouette, the incidence of ocular injuries in warfare is about 20 to 50 times higher than could be expected,” said Giorgio Romani, MD, head of the ophthalmology department at the Military Hospital in Rome.

Lateral curvature of the orbital margin extends the exposed surface of the eye laterally and increases the risk of injury from the lateral side, he said. More sophisticated war techniques and weapons have also contributed to the increase in ocular injuries.

“Improved munitions, which create increasingly smaller fragments, and also non-conventional or unknown munitions like those used in terrorist explosions, have multiplied the number of blast injuries and fragment injuries in the eye apparatus,” Dr. Romani said.

Fragment injuries are particularly common in trench warfare, where artillery inflicts wounds not only through bomb fragments and shrapnel, but also from stones, cement and sand turned into projectiles by the explosion.

The use of anti-personnel mines also accounts for a high number of eye injuries in some geographic areas, he said. In warfare in general, mines represent 9% to 15% of all munitions-related causes of ocular injuries.

“On the whole, blast wave contusions and blast fragmentation account for 68% to 78% of warfare ocular trauma,” Dr. Romani said.

A different type of damage to the eye is related to laser, which is used routinely in modern battlefields for target designators, rangefinders and radar warning. In the future, the incidence of laser-induced eye injuries might significantly grow, as the threat of the use of lasers as antipersonnel devices by enemy forces is “a real and increasing threat,” Dr. Romani said.

Protection of the eye during military operations is mandatory, he concluded. He recommended that shock-resistant eyewear to protect the lateral side of the orbit should be made mandatory.

Presentations from the International Society of Ocular Trauma are highlighted in this article. These items appeared first on the OSN SuperSite as daily reports from this meeting. Look to the pages of upcoming issues for expanded coverage of selected items.

Foreign body extractor

A simple device can safely and effectively remove larger intraocular foreign bodies with minimally traumatic maneuvers, one presenter said.

The instrument, developed by Claus Eckardt, MD, is a modification of the Erakgün snare. The device has a tubular handpiece with a retractable wire snare made of a metallic alloy that is capable of returning to its initial form after being bent. Once the instrument is inserted in the globe, the snare is pushed out. The loop is kept fairly large to surround the foreign body and is then tightened around the foreign body to firmly grasp and withdraw it from the eye. With this instrument, intraocular foreign bodies of different sizes and shapes can be removed easily, Tillmann Eckert, MD said.

“The loop of the extractor comes out at an angle of 80° and is able to hold and remove long objects almost vertically along the axis of the instrument,” he said.

“If additional maneuvers are needed, the extractor can be used like a spoon within the vitreous cavity to disengage and place the foreign body in the best position to capture it,” Dr. Eckert added.

Air bag project

The Airbag Project, a new initiative among international ocular trauma specialists, aims at reducing risk and preventing and limiting damage to the eye caused by air bag deployment.

“Air bags save lives and are also effective in protecting eyes from windscreen glass splinters, but safety still needs to be implemented,” said Cesare Forlini, MD, meeting organizer, chairman and scientific secretariat.

By exploding, the air bag can cause violent blunt ocular trauma. If the driver or passengers wear spectacles, fragments of the broken lenses can also cause penetrating injuries. Rings can cause similar problems, Dr. Forlini said. Lifting the hands to cover the face is the most instinctive reaction of self-protection in automobile accidents, he said.

The Air bag Project is collecting data from ocular trauma specialists worldwide to include in a database of air bag-related trauma incidents.

“We are doing this first collection of data by a questionnaire that aims to investigate the nature of the injuries, but also aims to collect information on the dynamics of the accidents that caused air bag-related injuries, the type of car and any other detail that can be useful to understand how we can help minimize the occurrence of trauma,” Dr. Forlini said.

Ferenc Kuhn

He said the information gleaned from the project will be publicized to ophthalmologists and other health care operators and will also be used in information campaigns for the general public.

Ferenc Kuhn, MD, executive vice president and meeting co-chairman, International Society of Ocular Trauma, who also spoke on the subject, said, “We don’t want to make people scared of air bags, but rather convince them of the importance of keeping a correct position in the car and of always using safety belts because only under these conditions can air bags save life and save vision.”

Dr. Forlini added that spectacle wearers should use polycarbonate glasses in the car.

“We also want to involve eyewear manufacturers and optometrists, so that they can implement the production, prescription and use of high-impact-resistance eyewear. Car manufacturers could be encouraged to develop safer air bags, with perhaps a soft lattice cushion at face level,” he said.

Endoscopy can be advantageous

Endoscopy can be valuable in trauma surgery, Claude Boscher, MD, said. Inadequate visualization in a traumatized eye can make surgery time consuming, and delay can lead to further complications such as formation of anterior proliferative vitreoretinopathy.

“Endoscopy completely bypasses the problem of media transparency. In a case of a completely opacified cornea, you can operate inside the eye without performing a corneal graft and eventually select keratoplasty for only the eyes where retinal problems have been solved,” Dr. Boscher said.

Endoscopy also allows surgeons to decrease the risk of anterior proliferative vitreoretinopathy, proliferative vitreoretinopathy development and ciliary scarring and secondary hypotony, she told attendees.

An endoscope allows surgeons to “perform an early removal of blood and an early removal of the entire vitreous base, whatever the conditions of the anterior segment,” she said. “You can also explore the posterior pole and evaluate the conditions of the retina before injecting [perfluorocarbon liquid] and control all subretinal maneuvers.”

Silicone oil removal can be performed more easily and thoroughly with endoscopy, Dr. Boscher said. The instrument is able to detect all the droplets of silicone oil trapped into the ciliary processes over the pars plana and the zonular system, preventing the risk of secondary glaucoma, she said.

Dr. Boscher has developed an autoclavable probe that she said should alleviate sterilization concerns. She stressed the importance of cleansing the superior part of the anterior vitreous base and dissecting any connection with the anterior segment at 360°. If left there, even small quantities of vitreous are able to redetach the retina or, in presence of a flat retina, to cause hypotony. A thorough cleansing of the ciliary margin, where stem cells are produced, also removes all the inflammatory cells that have been stimulated by the trauma.

Additionally, “tearing is not a big problem with endoscopy because you are controlling your maneuvers all the time,” she said.

Endoscopy-guided vitreoretinal surgery requires a learning curve that has often discouraged surgeons from using this technique. A major stumbling block for some surgeons is using only one hand to operate, as the other is used to hold the endoscope.

“However, learning to use the endoscope is easier than one might think, provided that specific instruments are used,” Dr. Boscher said.

Sympathetic ophthalmia still possible, but treatable

The prognosis for sympathetic ophthalmia is much better than in years past, according to one physician. Although this is a rare condition, it may still occur in some patients after trauma or surgery.

“The incidence of sympathetic ophthalmia has grown so small over the years that most young ophthalmologists have only read about it in old textbooks. In those days, it had a notorious reputation of being a severe chronic condition and producing a progressive deterioration of vision,” Mahmoud M. Soliman, MD, said.

Newer drugs and improved surgical techniques have helped physicians control sympathetic ophthalmia more successfully, often preserving vision. In a minority of genetically predisposed patients, sympathetic ophthalmia develops in the contralateral eye as a result of trauma. Stimulating the immune system against a particular protein triggers the reaction, Dr. Soliman said.

Inflammation can take the form of exudative retinal detachment or of an insidious chronic granulomatous reaction, ending in some severe complications. Often, rather than the inflammation itself, the first symptoms are the sequelae of inflammation, such as cataract and glaucoma.

Dr. Soliman said the prevalence is low. “In the U.K., it was found to be three out of 10 million post-surgery cases. The incidence is probably higher following trauma,” although probably still less than the 0.1% to 0.2% rate estimated in previous years, he said.

Surgeons should not ignore the various aspects of the condition, however, he said.

“This disease can be a consequence of surgical procedures. We should be aware of it. Second, sympathetic ophthalmia is not as fearful as it used to be and can now be controlled successfully,” he said.

Bottle cork injuries are fairly common events

Bottle cork injuries can cause disabling functional sequelae and are not as infrequent as generally believed, said one surgeon.

Bottle corks cause a distinct type of trauma, “characterized by a violent compression phase followed by rapid decompression, with lengthening of the anteroposterior axis beyond its physiological range. Most common consequences are hyphema, iridodialysis, traumatic cataract, vitreous hemorrhage, peripheral retinal breaks, retinal edema and secondary glaucoma,” said Gian Maria Cavallini, MD.

The most common cause of the injury is sparkling wine being accidentally opened as it is pulled from a shelf. Right eyes are more commonly injured than left, as most people hold the bottle in their right hands, Dr. Cavallini said. The average bottle cork can hit the eye in as little as 0.1 seconds, he said.

Plastic corks are more dangerous than traditional corks or metal caps, he said. “They accumulate more kinetic energy at the time of bottling and have consequently a more explosive discharge,” Dr. Cavallini said.

His hospital is located in a region known for producing sparkling red wine, he said. “Bottle cork injuries are relatively common here. Through a retrospective study of our cases, we found that these injuries more often occur in October, at the time of wine fermentation, and January, when more often the sparkling wine is consumed to celebrate the New Year,” he said.

25-gauge surgery more effective in post-traumatic cases than 20-gauge surgery

Use of a 25-gauge vitrectomy system offers considerable advantages for treating both the primary and secondary complications of trauma, according to a surgeon.

“The small, less traumatic, self-sealing surgical wounds of the 25-gauge system are preferable in these already damaged eyes. The smaller instrumentation allows for better access and easier maneuvering into small, tight spaces, as it is often required in trauma surgery,” Tarek S. Hassan, MD, said.

Today, the experience with 25-gauge surgery is “very different from what it was” a few years ago, he said.

“In the beginning, the instruments were quite flexible, allowing decreased movement in the eye during surgery. The light had poor intensity and spread, and no bimanual technique was possible. But since then, the latest technological advances have made 25-gauge surgery a better and better technique, and the technical challenges of the original system have been largely overcome,” he said.

A greater variety of instruments with improved characteristics allow for better maneuvering in the eye. New, high-quality, disposable instruments are also available, and improved light sources add significantly to the surgeon’s ability to see during surgery, he said.

Dr. Hassan recommended the use of electric rather than pneumatic vitreous cutters.

“At a speed of 1,000 cuts/minute the duty cycle of both instruments is about the same: 50% of the time open and 50% closed,” he said. “But if we increase the speed to 1,500 cuts/minute the pneumatic driver is closed 80% of the time, and this decreases quite significantly the flow rate and the amount of cutting that can be done.”

The higher flow rate of electric cutters means more efficient, successful vitrectomy, less vitreoretinal traction and fewer high-speed related complications.

A further advantage of 25-gauge vitrectomy is that ports are interchangeable, and at any point one or two sites can be converted to 20 gauge, he said.

“I hope that both the 25-gauge and the 20-gauge systems will continue developing. I suspect there will be a place for both. The art of medicine will surely figure out the appropriate treatment choice for each individual patient,” Dr. Hassan said.

Use caution in trocar placement with 25-gauge instruments

The trocar placement with 25-gauge systems in ocular trauma surgery can cause problems with globe pressure and wound leakage, said one surgeon.

“The 25-gauge vitrector is earning its place in ocular trauma surgery. The advantages of the handpiece are less tissue manipulation, less inflammation and discomfort, less time in creating the wounds and less astigmatism,” José Dalma, MD, told attendees. “However, one of the big disadvantages that I found in dealing with trauma is the trocar placement.”

Inserting trocars creates a “very high pressure in the globe,” he said. This can create more trauma in the eye and possibly wound dehiscence when dealing with an open globe injury.

“We have proven in dog eyes that even with a well-sutured wound and with an appropriate counter-pressure from the infusion line, the wound leaks when the trocars are pushed into the sclera. We tried this with both Alcon and Bausch & Lomb 25-gauge vitrectors, and the difficulty in entering the eye was similar,” he said.

Dr. Dalma measured the pressure increase during the trocar insertion in a small number of patients.

“The average pressure was 62 mm Hg and went up to 80 mm Hg in some cases. Surely, we don’t want to generate these pressures in open eyes,” Dr. Dalma said.

A standard 20-gauge knife “enters the sclera very smoothly, barely deforming the eye,” he said. Ocular trauma surgery with a 25-gauge system should still be limited to uncomplicated vitreous hemorrhage, uncomplicated retinal detachments and treating macular holes and epiretinal membranes, he said.

“I don’t think it’s a very good technique to use in fresh open globe injuries and when dealing with intraocular foreign bodies because you would have to perform a sclerotomy to get that foreign body anyway or to put in an instrument to get it out. Equally, I would not use it in complicated retinal detachment and severe proliferative vitreoretinopathy,” Dr. Dalma said.

For more information:

• Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.

• ISOT Rome 2006 was held June 29-July 1.