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Rupture is the most severe form of mechanical globe trauma and represents 32% of all open-globe injuries, according to the US Eye Injury Registry (USEIR) and the surveillance arm of the American Society of Ocular Trauma (ASOT).1 In the USEIR, 25% of ruptured eyes presented with no light perception vision and only 10% had greater than 20/40 final vision, while 80% had worse than 20/200. Ruptures are caused by a (relatively) large, blunt object that initially compresses the eye; once the resistance of the eyewall (i.e. cornea and sclera)2 is overcome, the eyewall opens at its weakest point.
Such a mechanism has three consequences: first, the wound is rarely located at the point of impact, but rather at predilective areas, such as the limbus, the insertion of the extraocular muscles, the insertion of the optic nerve or any area weakened by surgery or inflammation. Second, the injury is caused by an ‘inside-out’ mechanism, as the intraocular pressure (IOP) dramatically rises due to the impact of the object. The IOP elevation with subsequent opening of the eyewall brings the third consequence: tissue extrusion, be it uvea, vitreous or retina. The loss of intraocular contents continues until a new equilibrium with atmospheric pressure is reached. This equilibrium is reached when the IOP drops to zero or a tissue tamponades the wound, preventing further tissue prolapse. All of these outcomes have implications for management.
Most patients with a ruptured eye rapidly seek medical help, mainly because of the severe, sudden loss of vision, usually due to vitreous haemorrhage. In 74% of eyes (USEIR data), the wound is scleral or corneoscleral. Typically, there is also a conjunctival wound. If the conjunctiva is intact (occult rupture), the condition may initially remain undetected. The following signs may help to establish the diagnosis:
The IOP is usually low, although a high IOP does not exclude the possibility of an occult rupture: if the prolapsed tissue tamponaded the wound but the intraocular haemorrhage continues, the IOP may rise substantially before the extravasated blood tamponades the bleeding.
Of the signs listed above, loss of the iris has the highest specificity for making the diagnosis. If the presence of a wound is confirmed, evaluation should be stopped; fine details of the injury are best determined during surgery to avoid causing additional tissue extrusion and/or bleeding.
On the operating table, the surgeon must follow certain guidelines to achieve the best possible outcome. Once the diagnosis is made or the possibility of an occult rupture cannot be excluded, the ophthalmologist must arrange for immediate surgery. Any delay risks an expulsive choroidal haemorrhage, the most devastating complication of an open-globe injury. The other very serious complication, endophthalmitis, is less of a threat as the object has not penetrated into the eye; even if the wound is open, the direction of movement is for materials away from, not into, the eye. In the case of an occult rupture, the conjunctiva provides adequate protection. General anaesthesia is preferred; however, if this is not available, some type of local anaesthesia has to be considered, as opposed to automatically deferring surgery until general anaesthesia becomes available.
As a general rule, the sooner the wound is closed the better. However, this must be balanced by the availability of the facility and its infrastructure (materials, equipment, personnel), as well as by the surgeon’s experience. This concerns not only the wound closure itself but also the potential need for additional surgical manipulations (see below). An individual decision must be made taking into account every factor, including the severity of the injury and the wishes/ circumstances of the patient.
Only when an expulsive choroidal haemorrhage (ECH) occurs is it permissible to incarcerate tissues in the wound. In the vast majority of cases, the wound edges must first be cleaned of all materials, be they external (foreign bodies, debris) or internal (intraocular tissue). Following proper cleansing, repositioning is the goal, except for vitreous prolapse, which is preferably cut with the vitrectomy probe rather than using sponge and scissors. Even if the injury is over 24 hours old, every attempt should be made to preserve the iris.
Closure of a Scleral Wound
If the scleral wound is anterior, it is best to carefully open the conjunctiva so that the entire length of the scleral wound becomes visible. After proper wound toilette, permanent (e.g. 6-10 or 8-10 nylon) or absorbable (e.g. 6-10 or 8-10 vicryl) sutures are introduced according to the ‘50% rule’ (see Figure 2).
If the scleral wound is posterior enough to interfere with easy access (typically, extending past the equator), the ‘close-as-you-go’ technique is recommended (see Figure 3). The conjunctiva is opened anteriorly only, and the sclera is closed using the above-mentioned sutures starting from the wound’s proximal end. As the conjunctival edge is approached, it is opened further posteriorly, exposing another portion of the scleral wound. This approach minimises the risk of further tissue extrusion during manipulations aimed at securing space for closing the posterior aspect of the scleral wound. Once it becomes obvious that the wound is so posterior that the introduction of a suture unavoidably threatens to cause more tissue prolapse or risks an ECH, the scleral wound is best left open. The conjunctiva is carefully closed and a shield is placed over the eye to prevent external pressure. The body’s scar-formation process typically firmly closes the wound within days. Incarceration of tissues is the rule, not the exception, in these cases; this must subsequently be addressed from the inside.
Closure of a Corneal Wound
Only a few of the rules are mentioned here; the reader is referred to textbooks for more details.3,4 Suture introduction must be carefully planned as not only must the wound be watertight but it also has to restore as close to normal corneal anatomy as possible. Scars interfere with the patient’s visual rehabilitation (in the long term) and oedema interferes with vitreoretinal surgery (in the short term). In the USEIR, 53% of eyes with corneal trauma required vitrectomy. Unless the wound is in the limbus, interrupted – not running – sutures should be used to avoid flattening the corneal dome shape; 10-0 nylon is the preferred suture material. The suture should be 100% deep, i.e. the thread lies inside the anterior chamber. This is crucial to rapidly reduce corneal oedema but also to minimise tissue shift or override. On removal of a full-thickness suture, the eye must be sterilised as if it were going to be operated on. The surgeon should not grasp the cornea with forceps; if counterforce against the needle is needed, the conjunctiva should be grabbed. If the wound is angled, the first suture is placed at the angle; if the wound crosses the entire cornea, the Rowsey-Hays technique5 is recommended (sutures with large bites are first placed at the two ends, followed by gradually smaller bites as the sutures approach the centre in a centripetal fashion). Otherwise, the 50% rule can be applied.
Closure of a Corneoscleral Wound
The initial suture is at the limbus (this should not be full thickness to avoid introducing stem cells into the anterior chamber). This is followed by closure of the corneal wound; suturing the scleral wound completes the procedure.
Additional Procedures During the Primary Repair
These may include removal of a hyphema, injured lens, suprachoroidal haemorrhage, etc. (see textbooks6,7 for more details).
The main goals of vitreoretinal surgery are to clear the media opacity so that the surgeon can have a direct view of the retina and optic nerve head, treat retinal injuries already present or prevent them from occurring and assess/treat the condition of the ciliary body. Again, the reader is referred to textbooks for details;6–8 only a few important factors are mentioned here. The earlier the vitrectomy is performed, the more likely it is that retinal detachment and proliferative vitreoretinopathy (PVR) can be prevented (in the USEIR, 19% of eyes had retinal detachment at presentation). If conditions are optimal (see above), the surgeon may elect to perform comprehensive primary reconstruction: vitrectomy is carried out in the same setting with wound closure. The major risk is intraoperative ECH; therefore, it is recommended that only experienced vitreoretinal/trauma surgeons choose this option, and they must be ready and able to stop the haemorrhage and use primary silicone oil tamponade if need be.9
A reasonable alternative to such comprehensive primary reconstruction is to topically administer heavy corticosteroid therapy after the primary surgery and perform vitrectomy within the first four days post-injury.10 The ciliary body must not only be re-attached should it be found detached during surgery, but it also must be free of blood or any material (e.g. fibrin) that may induce anterior PVR and tissue destruction with resulting phthisis. If the lens is removed and the risk of PVR is considerable, it is best to remove the lens capsules rather than considering ‘in-the-bag intraocular lens implantation’ as the primary goal.
If the scleral wound is posterior and/or involves the retina, prophylactic chorioretinectomy11 (see Figure 4) should be considered. Early data from the international trial organised by the International Society of Ocular Trauma (ISOT) indicated that this can dramatically decrease the risk of PVR. It is not clear whether a (prophylactic) encircling band has any beneficial effect; it is up to the surgeon to make that decision. However, if a band is placed it is best to do so during the primary surgery to avoid performing the technique after the subconjunctival scarring process has started. Cryopexy should be avoided, especially if performed blindly, because it increases the risk of PVR by breaking down the blood–retina barrier.
While ruptures remain the most severe form of open-globe injury with much damage sustained at the time of impact, meticulous management is able to reduce the effect of secondary complications.