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Ocular TraumaOcular Trauma

Monika KapoorMS

Monika Kapoor MS, Rohan Chawla FRCS (Glasg), Koushik Tripathy MD,Ravi Bypareddy MD, Babulal Kumawat MD, Subodh Kumar Singh MD,

Pradeep Venkatesh MD, Rajpal Vohra MD, Yog Raj Sharma MS

Dr. Rajendra Prasad Centre for Ophthalmic Sciences,All India Institute of Medical Sciences, New Delhi

Trauma accounts for up to 12% of all rhegmatogenous retinal detachments (RRD) and is the most common

cause of RRD in children.

According to the USEIR (United States Eye Injury Registry):

Retinal involvement is seen in up to 31 % among all serious injuries. Retinal involvement is seen in 34% of closed globe injuries (CGI) compared to 29% in open globe injuries (OGI). OGI is defined as presence of full thickness wound in ocular coats (sclera and cornea). In CGI there is no full thickness wound of the ocular coats. Vitreous involvement is seen in 31% of all serious injuries. Vitreous involvement almost doubles in open globe injuries as compared to closed (40% vs 22%). Rate of vitreoretinal involvement among all serious injuries is 44%.

Traumatic retinal detachment is most common in the 20-39 age group (nearly 50%) and is seen more in males (80%).

Closed Globe InjuryGlobe deformation in four phases can explain the result of the impact

1. Compression;

2. Decompression;

3. Overshooting;

4. Oscillations.

Ocular features of blunt traumaCampbell1 classically described the seven rings of blunt trauma

1. Central iris: Sphincter tear

2. Peripheral iris: Iridodialysis

3. Angle recession: tear between the longitudinal and circular fibers of the ciliary muscle

4. Cyclodialysis: Separation of ciliary body from the scleral spur

5. Trabecular meshwork: Trabecular meshwork tear

6. Zonules/lens: Zonular tears with possible lens subluxation

7. Retinal dialysis: Separation or disinsertion of the retina from the ora serrata

One must be aware and watchful of these trauma related sight threatening complications particularly angle recession. Gonioscopic evaluation of the angle in all patients of blunt trauma must be done. Lifelong intraocular pressure monitoring may be called for in patients with angle recession.

Mechanisms responsible for retinal break formation:

• Vitreous base avulsion: may occur at the anterior attachment or posterior attachment of vitreous base.

• Abnormal sites of vitreoretinal adhesion (e.g., lattice degeneration).

• Coup injury: Local trauma at the site of scleral impact leads to a full thickness necrosis of the overlying retina.

• Contrecoup injury- at a location opposite to the site of impact.

• Sudden posterior vitreous detachment induction.

Traumatic Retinal Detachment

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Types of BreaksOcular contusion may result in numerous types of retinal breaks, including horseshoe tears, operculated holes, large irregular retinal breaks, macular holes, and, most often, retinal dialyses.

Retinal dialysis

It is defined as the disinsertion of retina from non pigmented epithelium of the ciliary body at the ora serrata. It is most commonly seen in inferotemporal quadrant, accounting for almost 66% of cases, superotemporal in 10% and inferonasal in 4% cases and 6% in more than one quadrant2. Though inferotemporal dialysis is the commonest location of traumatic dialyses, superonasal dialysis is pathognomonic of trauma. The inferotemporal dialysis can also be seen in bilateral inferotemporal dialysis of young without a history of trauma.

Indirect ophthalmoscopy and scleral depression is indispensable to rule out a dialysis and should be performed repeatedly until 360 degree ora can be visualised. The clinical presentation of the traumatic retinal detachment is usually delayed as they occur most commonly in the young individuals. This may be attributed to well-formed vitreous being attached to the edge of the break. Typically there is no posterior vitreous detachment. Most frequently the traumatic RRDs occur due to inferotemporal dialysis which progress slowly, usually with multiple subretinal bands, multiple demarcation lines, intraretinal macrocysts (Figure 1) and patient notes its presence only when fovea is involved. The superior field defect caused by inferior RRD is also rarely detected by the individuals as most routine works involve central and inferior visual fields. 12% of traumatic detachments are found immediately3. Thirty percent of traumatic RRD presents within 1 month, 50%

within 8 months, and 80% within 24 months4.

Therefore one must do a complete peripheral examination and follow up the patient until media clears or 360° indentation indirect ophthalmoscopy is possible. Visualization of the peripheral retina will allow early diagnosis and treatment. In the young and uncooperative patient general anaesthesia may be necessary. Repeated examinations may be needed if vitreous haemorrhage or pre-retinal blood obscures the view. Sometimes the dialysis may be difficult to appreciate because of minimal separation between retinal and ora. Particular attention should be given to the superonasal and inferotemporal quadrants. Index of suspicion is warranted in case there is vitreous base avulsion which is classically described as a “bucket handle”. Occasionally, a dialysis may seal spontaneously due to a chorioretinal response to the insult.

Peripheral retinal breaks

The location and configuration of flap horseshoe or “U” tears tend to mimic those associated with a spontaneous posterior vitreous detachment. Tears from full-thickness retinal necrosis are usually slower to evolve and also tend to be large, more irregular, and located at the site of direct ocular contusion especially temporally where globe is exposed maximally to external trauma.

Giant retinal tears (GRT)

GRT is defined as retinal tear involving 90° or more of the circumference of the globe (Figure 2). Myopic males appear to be at a higher risk of developing giant retinal tears from blunt trauma. These are associated with significantly more inflammation, hypotony, choroidal detachments, and

Figure 2: GRT with inverted flap.

Figure 1: Total RRD with subretinal bands.

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Ocular Trauma

proliferative vitreoretinopathy (PVR). PVR can progress very rapidly in a GRT. Vitreoretinal surgery in GRT requires special considerations to prevent slippage of the posterior flap for which perfluorocarbon liquids (PFCL) are of great help.

Is contusion really the cause for retinal detachment?

Confusion arises because of coexisting causes of retinal detachment namely trauma and pre-existing vitreoretinal degeneration. The one severe enough to cause RD, at times remains difficult to detect which may be important to differentiate particularly for medicolegal purposes.

This question was answered by Cox3 by giving the famous “Cox’s Postulates”.

1. ‘Unilateral retinal detachment preceded by ocular contusion.

2. Objective signs of contusion in the affected eye.

3. Absence of visible vitreoretinal degeneration of the types known to cause retinal breaks in both the affected and fellow eyes’.

At least one of the following objective signs of ocular contusion is required to call the trauma significant:

• Vitreous haemorrhage

• Hyphema

• Traumatic chorioretinal atrophy / pigmentation

• Traumatic cataract/ subluxation

• Lid laceration/echymosis

• Corneal abrasion/scarring

• Iridiodiaylsis

• Cycldialysis

• Angle recession

Management

Breaks without retinal detachmentAs the adage goes ’prevention is the best cure’ in posterior segment injuries too prophylactic treatment is advised in order to maintain good vision. It is imperative to localise and treat all breaks with laser retinopexy which may be done either on slit lamp with a contact lens or with the help of LIO in case of peripheral breaks or dialysis. The aim is to surround the break with 2 to 3 rows of moderate intensity burns. Cryoretinopexy may be used in case laser is not available, media is hazy, very anterior break or it is not possible to properly surround the break with laser.

Open Globe InjuriesIn penetrating trauma retinal detachment can take place from linear breaks caused by the perforation itself. And

retinal breaks may also occur because of vitreous traction bands which have resulted from the disturbance of the vitreous; these breaks tend to occur on the opposite side of the retina from the perforation site. The formation of the retinal breaks may be delayed for months or even years. Repeated fundus examination for a period of at least one year should be carried out to allow early diagnosis of the retinal breaks before retinal detachment occurs.

Eitiopathogenesis Penetrating ocular injuries incite a sequence of events which can ultimately lead to tractional and/or rhegmatogenous retinal detachment.

• Ocular wound leads to breakdown of the blood–retinal barrier and initiation of an inflammatory response.

• Then cytokines are liberated which recruit retinal pigment epithelial (RPE) cells, fibroblasts, and glial cells that proliferate within the eye.

• These cells produce collagenous extracellular matrix in the vitreous and on the retinal surfaces causing it to contract.

• When the normal adhesive forces between the neurosensory retina and the RPE are overcome by the contractile forces, a tractional retinal detachment ensues

• Over weeks, the intraocular proliferation progresses, leading to the formation of cyclitic, epiretinal, and retroretinal membranes.

• Posterior vitreous separation generally occurs during the first 2 weeks of injury.

• Presence of vitreous haemorrhage expedites the process.

Here it is important to note that intervention in form of vitrectomy for penetrating trauma (in view of vitreous haemorrhage, metallic intraocular foreign body) should be undertaken immediately around this 2 week period for best prognosis. This interval gives time for posterior vitreous detachment, better visualisation and better wound stability without significant proliferative changes.

Management of traumatic retinal detachmentTraumatic retinal detachment is treated like any other retinal detachment. The treatment options being:

• Pneumatic retinopexy (for superior breaks, within 1 clock hour, if patient can maintain position, phakic patients)

• Scleral buckling

• Vitreoretinal surgery

The choice of surgery mainly depends location of breaks / amount of proliferative vitreo-retinopathy and the surgeon’s

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preference. Below mentioned are the most acceptable options.

• Scleral buckling: may be the preferred surgery in cases of retinal dialysis, anterior breaks with fresh detachments especially inferior. Drainage may be done in long standing inferior detachments commonly seen following blunt trauma. It is also preferred in phakic young patients. For retinal dialysis this procedure has anatomical success rate of 90-95%.

• Vitreoretinal surgery: vitrectomy may be preferred in cases with multiple breaks, posterior breaks, GRT and significant PVR. Penetrating globe injuries leading to detachment are usually dealt with vitrectomy; this also includes detachments with retained intraocular foreign body. Dealing with PVR may be challenging and may require use of PFCL, relaxing retinotomy/ retinectomy, removal of subretinal membranes and encirclage for anterior PVR.

Visual outcomes are better when the macula is on, the height of macular detachment is less, and the macula is detached for a short duration (less than 7-10 days).

Prognosis depends on multiple factors:

• Presenting visual acuity

• RAPD

• Concomitant ocular trauma

• Macular hole,

• Subfoveal/juxtafoveal choroidal rupture,

• Chorioretinitis Sclopetaria,

• Traumatic optic neuropathy,

• Vitreous haemorrhage

• Type of break: GRTs are associated with more PVR

• Type of detachment: macula on vs macula off

• PVR

• Globe rupture

• Endophthalmitis

• Intraocular foreign body

ConclusionTraumatic retinal detachments present a different variety of RRD which is usually seen with phakic young patients. As dialysis is the commonest cause most cases can be successfully reattached with good visual recovery with scleral buckling alone.

References1. Campbell DG. In Shingleton BJ, Hersh OS, Kenyon KR (eds), Eye

Trauma. St Louis, Mosby 1991.

2. Zion VM, Burton TC. Retinal dialysis. Arch Ophthalmol.1980;98: 1971–74.

3. Cox MS, Schepens CL, Freeman HM. Retinal detachment due to ocular contusion. Arch Ophthalmol 1966;76: 678-85

4. American Academy of Ophthalmology, Basic and Clinical Science Course, Section 12: Retina and Vitreous. 2011; 278.

Ocular Trauma: Traumatic Retinal Detachment