What you need to know about treating perforating ocular injuries with CAM
By Beeran Meghpara, MD
Perforating Ocular Injuries: Trauma or Inflammation
Perforating ocular injuries are often a result of trauma. At Wills Eye Hospital, many referrals come through our emergency room. Patients may have been hit or poked in the eye with glass, metal, or an object that has lacerated or perforated the eye.
As a cornea specialist, however, I deal more frequently with another population of patients: those who experience corneal thinning, progressive corneal ulceration, or corneal melting as a result of an infection or an inflammatory process. Eventually, if one of these conditions is deep enough, it can cause a corneal perforation.
Whether due to trauma or inflammation, perforating ocular injuries present similarly. Patients may feel a sudden gush of fluid when the perforation occurs, so we warn all at-risk patients that if they experience such a sensation, they must come in immediately.
Initial Assessment
I carefully assess the area of perforation, focusing on its size, extent, and configuration. In addition to evaluating the corneal injury, I examine other intraocular structures for signs of iris trauma, damage to the crystalline lens, and chorioretinal injuries. Additionally, I carefully measure intraocular pressure (IOP), which is typically zero with a perforation. However, it is helpful to know if the pressure was elevated before the perforation occurred. Checking corneal sensation is crucial in patients with progressive corneal ulceration to assess for neurotrophic keratopathy. Any secondary issues within the eye significantly impact the ultimate prognosis.
The initial assessment also involves investigating for any underlying conditions such as infectious and autoimmune etiologies. When infection is suspected, I find it useful to culture the ulcer to help identify the causative agent and tailor treatment accordingly. For bacterial infections, broad-spectrum fortified antibiotics are typically used.
A thorough medical history is also important to identify autoimmune conditions such as rheumatoid arthritis and lupus. In cases of suspected inflammatory corneal melting, anti-inflammatory treatment is initiated, including steroids or immunomodulators for more chronic conditions. It is important to rule out infectious causes before starting these therapies.
Repairing the Perforation
The approach to repairing corneal perforations depends on their size and shape. If the perforation is circular and larger than 2 mm in diameter, it is not feasible to bring the edges together with sutures. In such cases, I opt for a corneal patch graft or transplant.
For perforations smaller than 2 mm in diameter, I apply cyanoacrylate glue into the concavity created in the cornea, effectively sealing the perforation. It is crucial to apply just enough glue to fill the perforation without excess spreading onto the corneal surface.
After applying the glue, which polymerizes and dries in seconds, I place a soft bandage contact lens on the eye. This procedure is minimally invasive and can be performed in the office without specialized equipment.
Following the closure of the perforation with glue, we allow the eye to heal, with the epithelium gradually filling in the divot and sealing the perforation. Once the perforation is sealed and epithelialized, the glue often falls off naturally. However, because the glue only serves to close the perforation rather than facilitate healing, recovery can take months or longer.
Treating Perforating Ocular Injuries With CAM
Cryopreserved amniotic membrane (CAM) offers several beneficial properties that make it a valuable alternative treatment for corneal perforations. CAM promotes epithelial growth, adhesion, and differentiation, which can facilitate sealing the perforation. Additionally, CAM has anti-inflammatory properties, promoting apoptosis of activated inflammatory cells and increasing the expression of anti-inflammatory cytokines.
For smaller perforations, multiple layers of CAM can be used instead of glue to fill the area of corneal ulceration. The CAM is cut and folded into several small pieces, which are applied to seal the perforation. CAM not only functions similarly to glue, but the properties inherent to the amniotic membrane also promote epithelialization and overall healing.
After packing the perforation with CAM, an additional layer is applied over the cornea and secured with five 10-0 vicryl sutures. Over approximately 1 week, the CAM layer on the corneal surface dissolves, while the CAM within the ulcer often becomes integrated into the cornea as the epithelium heals over it.
In my practice, I increasingly use CAM as an alternative to glue, especially for patients with underlying inflammatory or neurotrophic conditions, given its anti-inflammatory and regenerative properties.
Looking ahead, CAM shows promise in repairing exit wounds involving the retina and choroid. Traditionally, managing such wounds required waiting for scleral healing before performing vitrectomy, potentially leading to complications like proliferative vitreoretinopathy due to inward migration of scleral fibroblasts.
In a recent report, researchers describe a procedure in which CAM was used to seal the scleral exit wound from the inside of the eye, allowing for early vitrectomy. At postoperative month 4, the patient achieved a visual acuity of 20/30, and optical coherence tomography revealed orderly glial tissue covering the exit wound.1
Time Is of the Essence
In cases of perforating eye injury, timely closure of the hole is crucial. The multi-layered CAM treatment is typically performed in the operating room under sedation. However, with a patient agreement, it can also be performed in an office setting, in a minor procedure room. This flexibility contrasts with corneal patch grafts, which often necessitate more elaborate preparation and may require general anesthesia. I encourage practitioners to consider CAM, as it is readily available and has a long shelf life, making it convenient to keep on hand for urgent situations.
While glue may be the more common approach today, I have observed that patients report greater comfort and faster recovery with CAM. Therefore, expanding its use holds promise for enhancing outcomes in these cases.
Reference
- Hondur AM. Repair of the exit wound of a perforating globe injury with the amniotic membrane: a surgical adjuvant for early vitrectomy. Retin Cases Brief Rep. 2023;17(6):775-778. doi:10.1097/ICB.0000000000001297
Beeran Meghpara, MD, is the co-director of Refractive Surgery and a member of the Cornea Service at Wills Eye Hospital in Philadelphia. He is a fellowship-trained ophthalmologist specializing in cornea, cataract, and laser refractive surgery. He has a faculty appointment at Sidney Kimmel Medical College of Thomas Jefferson University and is a team ophthalmologist for the Philadelphia Phillies baseball team.
