Fig. 14.1
BETT system
In particular, “contusion” is used when the eye wall is not injured whereas “lamellar laceration” refers to a partially damaged eye wall. “Laceration” and “Rupture” are used when a full thickness injury of eye wall occurs; these terms differ according to traumatic mechanism, respectively, determined by a sharp or a blunt object [2, 3]. Once the type of injury is determined, the patient may undergo clinical and instrumental evaluations. In this context, both general and specific exams may be adopted in order to obtain a global description of the patient’s clinical conditions. A list of useful examinations, including both conventional ophthalmologic and more specific exams, is provided in Fig. 14.2.
Fig. 14.2
Clinical and instrumental evaluation of eye trauma. Ophthalmologic assessment of ocular damage includes the tests showed in pink box. This first evaluation may be followed by more specific exams (orange box), according to the clinical picture. If larger involvement of extraocular structures occurs, multidisciplinary evaluation may be considered (violet box)
It is worth noting that an eye may be involved alone, thus requiring only ophthalmologic treatment. On the other hand, ocular damage may only be one part of a multi-system trauma, i.e., in the polytraumatized patient; in the latter case, the ophthalmologist is involved secondarily, after the patient’s stabilization following the ABCDE rule assessment (airway, breathing, circulation, disability, and exposition) [4].
After clinical and instrumental evaluation of the ocular damage, an important step is to quantify visual prognosis. The Ocular Trauma Score (OTS) [2, 3] is a set of six factors, which provide a prediction of the patient’s visual acuity recovery at 6 months follow-up. OTS scores range between 1 (worst prognosis) and 5 (good prognosis). OTS predictive factors and associated scores are shown in Fig. 14.3. The clinical usefulness of OTS has been verified by a number of studies showing the utility of OTS for the evaluation of an injured eye [5–7].
Fig. 14.3
Predictive factors and computation of OTS score
OTS score is a reliable predictor of visual prognosis when assessing an open globe injury. Conversely, a deeper investigation is required when other serious conditions, such as endophthalmitis and retinal detachment, occur in the trauma patient [8].
Imaging of the Injured Eye
Imaging of the injured eye (see Fig. 14.2) consists of a number of techniques, which permits a deeper study of the effects of trauma on ocular as well as orbital structures. These represent advanced investigations required when conventional clinical approaches are not sufficient to assess structural alterations after trauma, especially when the posterior segment and the optic nerve are involved. The initial clinical evaluation is critical, since the spectrum of alterations induced by trauma can involve, alone or in combination, several structures. Indeed, previous studies conducted in patients with blunt trauma have shown that traumatic manifestations may include the retina, choroid, optic nerve, and vascular compartment [9, 10]. Regarding the anterior segment, a number of injuries might be expected resulting from direct trauma as well as those associated with posttraumatic factors [11–15]. A list of the most frequent ocular injuries is provided in Fig. 14.4. Other authors have emphasized that trauma most commonly occurs in the young [10]; this should be taken into account when deciding proper therapy as well as when evaluating expected prognosis after ocular trauma.
Fig. 14.4
Traumatic injuries of eye’s structures
A brief description of the most commonly used approaches and their specifics is provided below.
Optical Coherence Tomography
Optical Coherence Tomography (OCT) is a noninvasive technique providing microstructural evaluations of the eye’s components by means of a laser source and allowing an accurate investigation of eye structures; it is largely used for investigating retinal layers [16]. This approach has been found to be useful for assessing the effect of trauma on the posterior segment as well as for posttraumatic follow-up [17–19]. Moreover, OCT has been reported to clearly detect optic nerve avulsion [20]. Furthermore, a number of studies have shown that OCT may provide useful microstructural information regarding traumatic involvement of the anterior segment [21–23].
Angiography
Angiography is a method for the evaluation of the eye’s circulation by adopting contrast agents. It is able to evaluate retinal (by means of a fluorescein agent) as well as choroidal circulation (by means of an indocyanine green agent); perfusion alterations are detected as hypofluorescent areas whereas neovascularization processes are shown as hyperfluorescence. Angiography has been reported to be more sensitive for vascular evaluation when compared to conventional ophthalmoscopy [24]. This technique has been found useful especially for assessing traumatic choroidal damage; this can occur with different degrees of alterations which have been clearly detected by indocyanine green angiography [25]. Further, the use of this method has been found to play a role for predicting the visual prognosis in patients with traumatic choroidal involvement [26].
Ultrasonography
Ultrasonography is a noninvasive imaging technique showing morphological images after elaboration of sound echo-ography provided by sound reflection by different tissues. Previous studies have reported its utility for different traumatic injuries, including the evaluation of suspected foreign intraocular body [27], lens damages with phacocele [28] as well as optic nerve involvement [29], thus suggesting a greater utility in different clinical contexts. As stated earlier in the chapter, when rupture of the globe is suspected, ultrasound should not be performed as the pressure from the probe may cause extrusion of intraocular contents.
Computed Tomography
Computed Tomography (CT) is a frequently used imaging technique for structural evaluation of orbital structures and bone-related trauma. It uses radiation to obtain images, based on different tissue densities. CT is the first choice when a bone fracture is suspected; it is useful in cases of orbital perforation as well as foreign body injury [30]. CT is able to detect corneal laceration as well as lens damage [31]; moreover, it can distinguish open globe injuries, extraocular muscle damage, and orbital compartmental syndrome [31–34]. CT can also evaluate vitreous hemorrhage and retinal detachment [35], although its sensitivity is poor [34]. Indeed, it was found that magnetic resonance imaging may be more sensitive when assessing soft tissue involvement, showing detailed images of ocular structures [34, 36].
Magnetic Resonance Imaging
Magnetic Resonance Imaging (MRI) is a powerful imaging technique which allows morphological evaluation of ocular structures through elaboration of signals produced by adopting two perpendicular magnetic fields and radiofrequency pulses. By setting MRI parameters, it is possible to obtain T1 and T2 weighted acquisitions; these allow different evaluations of body tissues. It has been reported that MRI permits detailed evaluations of ocular and orbital structures, especially by using specialized types of scans, such as diffusion weighted imaging [31, 34]. MRI is able to provide a more detailed evaluation of optic nerve by using fat suppression during acquisition, compared with CT [37]. For this kind of study, T1-weighted, T2-weighted Turbo Spin Echo, fluid attenuation inversion recovery, diffusion weighted as well as T1 inversion recovery coronal acquisitions can provide useful information regarding optic nerve involvement in pathological conditions, e.g., optic neuritis and neuromyelitis [38–42]. Although MRI offers several advantages for these kinds of evaluation, especially if adopting advanced postprocessing techniques, its use in ocular trauma is limited when compared to CT because of longer acquisition times, as well as higher costs. Moreover, another MRI limitation is related to the presence of metallic objects (e.g., metallic foreign body) and metallic devices (e.g., cardiac pacemaker), which are contraindicated with MRI, due to magnet induced movement of metallic foreign bodies.
Eye Trauma and Travel
Management of ocular trauma and travel requires careful adoption of appropriate preventive measures in order to avoid worsening of a given ocular injury as well as the onset of “ex novo” complications. After the initial treatment, it is important to reduce the risk of infection through adoption of proper topical and/or systemic antimicrobial therapy, covering both gram+ and gram− pathogen infections [43]. Based on the intraocular pressure (IOP), the use of hypotonic drugs might be required in order to reduce the risk of damage induced by an increase in ocular pressure [44]. In this context, prostaglandin analogs should be avoided because of their pro-inflammatory effects. If the patient needs to travel by plane, a number of preventive measures should be adopted. In particular, stabilization of the ocular surface is required. Indeed, dryness is the most common complication of staying in air-conditioned environments (both transports and closed spaces). Air-conditioning may cause changes in air humidity, thus increasing the risk of infection; for this reason, it is important to consider tear substitutes, re-epithelizing substances, protective lenses, and/or bandages if indicated. In patients who undergo pneumatic retinopexy or vitrectomy, airplane travel must be avoided for 15 days after the procedure. Gas reabsorption must be confirmed in order to avoid the risk of globe explosion caused by gas expansion, induced by high altitude.
Therapy and Long-Term Management
Changes of angle structures induced by chronic inflammation can be observed, producing irido-corneal synechiae or membranes with subsequent trabecular meshwork occlusion and drug resistant ocular hypertension. In order to prevent this complication as well as damage to the retina and optic nerve, an accurate long-term posttraumatic management of ocular inflammation is needed. Angle alterations may occur also in cases of traumatic hyphema; in the latter case, an angle recession can be observed, as well as iridodialysis or cyclodialysis. These changes may cause a secondary glaucoma due to obstructed outflow of trabecular meshwork. A noteworthy condition is iridodialysis, which may create a direct communication between the anterior chamber and choroidal space, thus causing ocular hypotony. If secondary glaucoma surgery fails, due to scarring phenomena interfering with therapeutical process, antimetabolite drugs and tube drainage systems may be necessary [45–51].
Chronic inflammation after vitrectomy and/or foreign body removal usually induces the release of inflammatory factors, with the recruitment of inflammatory cells, fibroblasts, and RPE cells in the retinal layers, thus leading to PVR formation [52]. An optimal management of risk factors combined with particular attention to the onset of emovitreous, inflammation, or infective processes may help to prevent PVR formation; in the case of significant PVR, surgical removal may become necessary.
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