Anterior Segment Trauma: The Fundamentals of Management

Abstract

Anterior segment trauma is the one of most common ocular condition seen in accident and emergency The ocular trauma may vary from minor injury such as a corneal abrasion to a grievous sight threatening injury such as a corneo-scleral tear or a chemical injury. The most crucial element in the management of ocular injuries is a thorough examination to identify all possible injuries to the eye and institute the appropriate treatment. The initial management plays a very important role in determining the prognosis of the vision, the need for further surgeries and also provide us with a realistic goals of visual rehabilitaion. In this chapter we aim to enumerate the common modes of ocular injury, manifestations of ocular trauma, the diagnostic features and provide the reader with a comprehensive overview of the treatment instituted. We will also include the accepted international trauma scoring systems and their utility in prognosticating the visual rehabilitation.

1. Introduction

Anterior segment ocular trauma is the one of most common ocular condition seen in accident and emergency. The ocular trauma may vary from minor injury such as a corneal abrasion to a grievous sight threatening one such as a corneo-scleral tear or a chemical injury. It has been said to be the most underdiagnosed trauma. In US the prevalence of ocular trauma is 1400 per 100,000US persons with an annual incidence of 8.1 per 100,000. This number is variable depending on the geographic location and more importantly on the occupational safety standards enforced in each country as it is said that 90% of the ocular trauma could have been prevented with protective eyewear.

The most crucial element in the management of ocular injuries is a thorough examination to identify all possible injuries to the eye and institute the appropriate treatment. The initial management plays a very important role in determining the prognosis of the vision, the need for further surgeries and also provide us with realistic goals of visual rehabilitation. In this chapter we aim to enumerate the common modes of ocular injury, manifestations of ocular trauma, the diagnostic features and provide the reader with a comprehensive overview of the treatment instituted. We will also include the accepted international trauma scoring systems and their utility in prognosticating the visual outcome.

2. Ocular trauma classification

Most of the injuries involving the eye, have a bearing on the anterior segment as it is considered to be the most vulnerable part. This is because the structures are usually unable to outlast the impact an injury can have, due to lack of stretchability, presence of highly specialised structures that have poor healing and hence leads to a permanent non-functioning scar tissue [1].

Starting from the anterior-most structure, the possible types of injuries that might be inflicted onto the anterior segment structures are as follows: eyelid edema, eyelid tear, corneal abrasion, focal or total epithelial defects, corneal laceration, corneal perforation, foreign body implantation, scleral tear, iridodialysis, hyphaema/microhyphaema, traumatic iritis, angle recession, traumatic cataract, lens dislocation [2]. Based on the mode of injury they can be broadly classified as mechanical, thermal and chemical injury. There are many classifications of the ocular trauma and the most widely used one is the Birmingham’s eye trauma terminology system (BETTS) which is listed in Figure 1. This was developed by the ocular trauma classification group in 2002 [3]. This classification mainly concentrates on the mechanical injuries. The classification system helps in standardising the terminology used in ocular trauma for prognostic staging as well as for research purposes to quantify the injuries and to study the outcomes of each and every type of insult.

Figure 1.

BETTS ocular trauma classification.

The system broadly classifies mechanical injuries into open and closed globe injuries. Open and closed globe injury is further classified based on the type and grade of injury (based on visual acuity at the time of presentation), presence of relative afferent pupillary defect, position of injury (posterior-most part affected in closed globe injury and the location of injury in case of open-globe injury). The definitions of the injuries are as follows.

1. Closed globe injuries: include injuries that do not involve a full thickness corneal/scleral/corneoscleral tear and it can be due to blunt force (also called contusional injuries), lamellar-lacerating injuries and those that result due to superficial foreign bodies [4].

   1. Contusional injuries: mainly occur due to a blunt object. The impact can be thus at the site of affliction or at a distant site due to anatomical changes in the globe structure.

   2. Lamellar lacerating wounds: injuries due to sharp objects causing a tear, however, these are only partial thickness tears and the site of insult is at the point of infliction.

   3. Superficial foreign bodies: Include foreign bodies lodged in the bulbar or the palpebral conjunctiva or in the sclera but do not cause a full-thickness tear.

2. Open globe injuries: These are injuries that include tears that are of full thickness of the eyewall (restricting the term “eyewall” here to the taut structures—sclera and cornea). Open globe injuries include rupture, laceration and penetrating injury.

   1. Ruptureis defined as a full-thickness tear at the weakest site of the eyeball due to blunt injury and the site of the rupture may or may not be at the site of the infliction of the blunt injury.

   2. Lacerationis defined as a full-thickness tear due to sharp objects. Usually the site of impact is affected.

   3. Penetrating injuriesare due to entry of sharp objects into the eye with no exit site.

   4. Perforating injury: if there is an exit site along with the entry site it is called as a perforating injury.

Kuhn et al. introduced a system of prognosticating the visual outcome based on presenting visual acuity and pupillary reaction and the zones of eye ball involved but it was not commonly used. Further in 2002, a new ocular trauma score (OTS) (Figure 2) was developed to help primary physicians to prognosticate the eye injuries and help them in communicating to the families [5]. Its usefulness has been established in some patients undergoing the three port pars plana vitrectomy for Intra-ocular foreign bodies and it was found that the post operative visual outcome was similar to the OTS prognostication [6]. However there are limitations to the OTS as it does not take into account any other type of injury other than mechanical injury such as thermal and chemical injury nor does it include significant facial and adnexal injuries that might have an impact on the visual outcome.

Figure 2.

Table of ocular trauma score.

Addressing these issues Shukla et al. have proposed a new classification system which is a more comprehensive classification and includes injury to adjacent structures and associated injuries such as face and head injuries [7].

2.1 Mechanical injuries

2.1.1 Lids

Eyelid injuries can occur due to blunt trauma, cutting injuries or road traffic accidents. The most common injuries are eyelid edema and echymoses (Figure 3). These are cosmetically more significant and worrisome for the patients. They usually resolve spontaneously but require a detailed evaluation so as to not overlook any underlying serious pathology to the eye.

Figure 3.

A female patient with RTA presented with lid echymosis and edema with abrasions over the eye lid.

The eyelid lacerations can be classified as the following types [4]:

1. Simple and superficial or deep not involving the lid margin.

2. Lacerations involving the lid margin

3. Lacerations involving the canaliculi

Lid lacerations more than 2 mm in linear length require suturing. The contaminated wounds would require debridement of necrotic tissue and suturing. If the wound is infected and necrotic then delayed suturing is planned or else all lid lacerations require primary repair.

Figure 4.

Deep laceration involving the superior aspect of upper lid which was subsequently sutured in layers.

Figure 5.

Deep laceration involving the lateral aspect of both lids. If these sutures are nor sutured correctly it can lead to a disfiguring scar.

Figure 6.

A 56 year old female patient who came with history of blouse hook injury of the lower lid which was sutured using the step-wise approach.

1. Simple superficial injuries require approximation with interrupted sutures with 6-0 silk or 6-0 plain gut suture. Care must be taken to evert the skin while taking bites and tight sutures should not be applied. They usually do well with minimal scar

   Deep lacerations require suturing of different levels (Figure 4). Muscle has to be sutured with 6-0 vicryl and skin with 6-0 silk (Figure 5).

2. Marginal lid tears repair involves a step-wise approach

   The step wise approach can be summarised as follows:

   • Step 1: The edges of the eyelid margin have to be approximated using 6-0 Silk suture by placing a simple interrupted suture at the grey line. It should be made sure that the sutures are not tied.

   • Step 2: The tarsal plate has to be identified and partial thickness interrupted sutures using 6-0 absorbable suture will have to be placed to close it. This is the most critical step to maintain the structural integrity of the lid.

   • Step 3: Place a 6-0 silk suture closer to the lash line and the suture at the grey line can be removed.

   • Step 4: Suture skin using 6-0 silk with interrupted sutures.

   It is very important to suture the marginal lid tears carefully as a well done repair avoids many complications such as trichiasis, ectropion, entropion and cosmetically unacceptable notch. These can be avoided by a meticulous primary repair (Figures 6 and 7).

3. Eyelid laceration with canalicular tear: These tears require a ministent/Crawford stent/aurostent to be placed during the primary repair to ensure patency of the canaliculus. Once the stent is placed and anchored, skin over it is sutured with interrupted sutures.

Figure 7.

A patient with both upper and lower lid laceration involving eyelid margins shows a healed scar with well apposed lid margin.

2.1.2 Conjunctiva

Conjunctival insults are invariably associated with mechanical trauma to the eye. Conjunctival chemosis and subconjunctival haemorrhage are the most common manifestation of any ocular injury. Conjunctiva can be affected with orbital fractures and even trivial trauma such as finger nail injury.

2.1.2.1 Red flags associated with subconjunctival haemorrhage/conjunctival tear

1. Presence of a bullous sub conjunctival haemorrhage (Figure 8)

2. Conjunctival tear along with subconjunctival tear

3. Associated shallow anterior chamber

4. Associated hyphaema.

Presence of any of the above associations warrants a detailed examination to rule out underlying scleral tear. A dilated fundus examination has to be done to rule out posterior segment injury.

Figure 8.

Bullous subconjunctival haemorrhage which subsequently was attributed to an extensive scleral tear after thorough examination. This patient presented with eye injury following a self-fall at home. Patient underwent primary repair but the visual prognosis was guarded and eventually resulted with phthisis bulbi.

2.1.2.2 Management

Subconjunctival haemorrhage does not require any treatment. Reassuring the patient is all that is required.

Conjunctival tears can be left unsutured unless they are very large tears or tears extending to the fornix which require suturing with 8-0 absorbable suture such as vicryl.

2.1.3 Cornea

2.1.3.1 Corneal abrasion

Being the anterior-most structure of the eye, it bears the brunt of all injuries. The corneal epithelium may have defects, and can range from superficial corneal abrasions to total epithelial defects. As the cornea is highly innervated, abrasions are very painful. It usually takes around 24–48 h for the corneal epithelium to heal [2]. Sometimes it is possible to examine and diagnose the cornea directly under torchlight, however, staining with fluorescein will be required in most cases to diagnose. Any defect will be readily demonstrated by fluorescein staining (Figure 9) [8]. Such defects get healed by “sliding” over of limbal epithelial cells and adhesion of these cells may take up to 6 weeks. Deeper defects will create transformation of keratocytes to myofibroblasts and thus creates scarring of the cornea [9].

Figure 9.

A traumatic corneal abrasion as seen after fluorescein staining and observation under the cobalt blue light.

2.1.3.1.1 Management

Once an epithelial defect is noted, careful examination has to be done to rule out any foreign body in the superior palpebral conjunctiva and it may be required to do a double eversion of the upper palpebral conjunctiva to examine the fornix and rule out foreign bodies. If no foreign body is detected then the next concern will be to identify is there are any infiltrates along the margin of the epithelial defect. If there are no infiltrates then the eye can be patched with an antibiotic ointment (e.g., chloramphenicol) and lubricating gel and the patient has to be reviewed after 24 h. If there is any discharge or a small defect and patching is not advised and antibiotic eye drops and prophylactic antibiotics are prescribed. The management protocol for corneal abrasion has been shown in Figure 10.

Figure 10.

Management of corneal abrasion.

2.1.3.2 Conjunctival and corneal foreign body

Ocular surface foreign bodies are the second most common type of ocular trauma. The most common aetiology is fall of foreign body into the eye during works such as welding, grinding, hammering or driving without protective eye wear. The patients give a positive history and they usually seek medical help earlier because of the discomfort.

Though the history of fall of foreign body is important but the patients description of the location should not be the guiding point for examination as most often this can be misguiding and foreign bodies may be found elsewhere [10].

When a patient presents with fall of foreign body one needs to a systematic examination to rule out foreign body.

Step 1: Examine the ocular surface for the presence of foreign body (Figure 11)

Figure 11.

A superficial corneal foreign body.

Step 2: Retract the lower lid to examine the lower palpebral conjunctiva and evert the upper lid and examine the superior palpebral conjunctiva as the subtarsal sulcus is a common location for lodgement of foreign bodies (Figure 12).

Figure 12.

Staining of cornea on eversion of the upper lid was found to have a metallic foreign body in the sub tarsal sulcus.

Step 3: If no foreign body is found then stain the surface with fluorescein dye and examine the ocular surface under cobalt blue filter. This usually reveals any abrasion of the cornea and will likely indicate the position of the foreign body (Figure 13)

Figure 13.

Corneal abrasion, evident on fluorescein staining.

Step 4: If no foreign body is found in all the above steps but there is a strong suspicion of foreign body then double eversion of the upper lid has to be done. This is usually rare but some foreign bodies can get lodged there (Figure 14).

Figure 14.

Double eversion of the eyelid is done using the Desmarre’s lid retractor to look at the superior fornix.

2.1.3.2.1 Management

Once the foreign body (FB) is found it has to be removed as early as possible. The foreign bodies can be superficial or deep. Superficial foreign bodies in adults can be removed under topical anaesthesia under slit lamp. After applying local anaesthetic like proparacaine, the FB can be removed with a cotton tip applicator if it is less than 24 h old. If it is >24 h, it has to be removed with a bevelled 26 G needle. In case of a metallic FB, care should be taken to remove the rust ring completely as the rust ring can cause increased inflammation of the surrounding cornea and leave a scar. If this is in the central cornea it can affect vision.

If it is a deep foreign body, it may be difficult to remove the rust ring completely. These patients have to be called after 24 h and complete removal of the rust ring has to be done.

Deep foreign bodies revealing a full thickness lodgement in the cornea have to be removed only in the operating theatre as these cases may require suturing of the cornea after removal of the foreign body.

In children examination can be very difficult. These patients require examination under anaesthesia and removal.

2.1.4 Traumatic iritis

Blunt or penetrating injuries can lead to traumatic iritis. Usually patients with iritis report late. Following injury, they develop iritis over a few days and may seek help only after few days once the symptoms of pain, watering and photophobia set in. On examination fine keratic precipitates and flare and cells in the anterior chamber will be found and the pupil will be miotic or may show some sphincter tears and mydriasis. IOP may be normal, low or high.

2.1.4.1 Management

They have to be started on steroids with a careful follow up of IOP to rule out steroid responders. And cycloplegics have to be started.

Once the iritis resolves all these patients have to undergo gonioscopy to rule out angle recession.

2.1.5 Traumatic hyphaema

Blood in the anterior chamber is called hyphaema. Trauma is the most common cause. Compressive forces can cause damage to the iris, ciliary body, trabecular meshwork and thus disrupt the vasculature and thus cause bleeding. Very rarely it can be because of bleeding dyscrasias. Blunt trauma especially ball injuries, sports injuries and firework injuries can cause hyphaema.

Hyphaema can be graded as follows:

GRADE I: no visible layering of blood but only red blood cells in the anterior chamber (AC) seen only under the slit lamp—called as micro-hyphema

GRADE II: blood that occupies less than one third of the AC

Grade III: blood that occupies one third to half of the AC

Grade IV: blood that occupies the whole AC.

Bright red blood in the AC is called as “total hyphema” and dark red blood in the AC is called as an “8-ball hyphema” or a “blackball” hyphema. It is important to distinguish between the two as the latter suggests longstanding blood in the AC possibly due to pupillary block which could be alarming as it can lead to secondary angle closure [11].

If the grade of hyphema is less than 2 then they can be treated on OPD basis. But a grade 3 and above require inpatient admission as prompt management of complications that can arise will help in saving vision.

2.1.5.1 Management

1. Hyphema that are uncomplicated are usually managed conservatively by asking the patients to have limited head movements along with covering the eye with an eye-shield.

2. It is particularly useful to ask the patients to have head-end elevation at around 30–45° so that the hyphema settles inferiorly. This allows patients by not obstructing the visual axis and also in limiting contact between the red blood cells and the corneal/trabecular meshwork in other areas [12].

3. Intraocular pressure should be frequently monitored. If found elevated, topical medication should be started (antiglaucoma medication such as B blockers (timolol 0.5%) and alpha agonists like brimonidine tartrate 0.2% thrice daily can be used but best avoided in paediatric age due to the risk of apnea) or carbonic anhydrase inhibitors (dorzolamide 2%) drops can be used. Prostaglandin analogues have to be avoided. Systemic carbonic anhydrase inhibitors are also effective for e.g., acetazolamide and/or methazolamide are some options that can be used in paediatric and adults alike. The former may be given orally or intravenously (IV) at a dose of 5 mg/kg four times a day in children and 250 mg four times in adults. The latter however, is given orally at a dose of 3 mg/kg four times a day in children or 100 mg three times per day in adults.

4. Topical steroids like prednisolone acetate 1% in tapering dose based on the amount of hyphema to limit inflammation. Started as 8 times a day and tapered according to the response. If the grade of hyphema is 3 or more then oral Prednisolone has to be started at 0.5–1 mg/kg body weight.

5. Topical cycloplegic agents like homatropine 2% twice daily to relieve pain due to ciliary spasm/photophobia.

6. Aminocaproic acid and tranexamic acid are two novel lysine analogues that prevent plasmin from attaching to the formed fibrin clot and thereby preventing dissolution of the clot. It also prevents the conversion of plasminogen to plasmin, and thus further reduces clot dissolution. Aminocaproic acid can be administered at a dose of 50 mg/kg orally every 4 h (total cumulative dose not exceeding 30 g/day) and tranexamic acid can be administered at a dose of 25 mg/kg orally three times daily (total dose not exceeding 1.5 g/day).

2.1.6 Iris and pupil

Immediately following injury there can be traumatic miosis however traumatic mydriasis is more common. Tears of pupillary margins were found to be the most common manifestations. Small sphincteric tears are known to cause notches whereas more severe cuts (like those extending from the margins to the root) cause severe compromise of the function of the iris. This can lead to traumatic mydriasis of the eye.

Apart from tears, other injuries sustained by iris are—iridodialysis which is the separation of the iris root from its attachment at the ciliary body which is visible on gonioscopy.

2.1.7 Lens

Lenticular damage that can be inflicted can be either due to lens opacification with or without dislocation. According to Canavan et al. [1], localised anterior cortical lens opacities and posterior cortical lens opacities can be present. These opacities were found to be punctate or also known ‘cobweb’ type and in some instances the typical rosettes can be seen. Vossius ring is the imprint of the pupillary margin against the anterior capsule during the time of injury and this gives an indication of the severity of the injury. Focal lens opacities due to posterior synechiae and acute ocular hypertension (glaucomflecken) are also reported following trauma.

Cataract can be seen as anterior or posterior cortical opacities. The cataract can be due to increase in permeability of the capsule or due to tear in the anterior capsule. If the anterior capsule is not torn then the cataract can be removed in a second surgery once the inflammation reduces and the corneal curvature stabilises as the Intra ocular lens calculation will be more accurate. But however, if the anterior capsule is breached then the cataract extraction has to be done as a primary procedure.

2.2 Open globe injuries

1. Conjunctival tears: Conjunctival tears can occur either due to blunt or sharp injuries. Presence of a conjunctival tear warrants a thorough examination of the underlying structures for e.g., scleral tears may be concealed underneath. If there are no other injuries conjunctival tears can be left unsutured unless they are very large tears or tears extending to the fornix which require suturing with 8-0 absorbable suture such as vicryl. If the conjunctival tear is associated with shallow anterior chamber and hyphema then the clinician has to be vigilant to rule out any occult scleral tears

2. Corneal tears: Corneal tears are the most serious injuries that require immediate surgical management to preserve vision. If treated appropriately and a good primary repair usually ensures a good visual acuity if no other posterior segment structure involved.

Corneal tears: Corneal tears can be infected or non-infected. Non infected wound requires a different management. First, we will look into management of clean corneal lacerations.

Any sclero-corneal tear warrants to rule out any other injuries which could be life threatening. Only once this is confirmed and other injuries ruled out the corneoscleral tear is managed.

The corneal tear has to be examined to rule out presence of incarcerated intraocular tissue or a intra-ocular foreign body. Most of the times it may not be possible to do a complete examination in the OPD or emergency and a complete examination is possible only during the surgery. Hence the history of the mode of injury is very critical to anticipate what needs to be kept ready during surgery. If an intra-ocular FB is suspected one needs to have the vitrectomy machine ready and possibly a posterior segment surgeon has to be informed. If a break in the anterior capsule is seen then cataract surgery instruments have to be ready and the OT staff have to be informed about these as it is important to have all the instruments ready and a complete surgery is possible only if these are anticipated and the primary surgery has to be performed with utmost precision as this will have an impact on future surgeries.

Timing of the surgery: The cornea-scleral tears have to be repaired as early as possible but however it has been shown that within 36 h of injury the occurrence of endophthalmitis does not significantly increase.

The management protocol has been shown in Figure 15.

Figure 15.

Schematic diagram showing management of corneal tear.

The goals of repair are:

1. Watertight wound

2. Prevent infection

3. Minimise scarring and astigmatism

Lamellar tears: Undisplaced lamellar tears (Figure 16) in the cornea can be treated with a bandage contact lens and antibiotics. These also have to be seen after 24 h and confirmed that there is no increase in the displacement or any infiltrates have to be ruled out and the same treatment can be continued.

Figure 16.

An undisplaced lamellar tcornea tear with mucus accumulation.

Figure 17.

A child with a pencil injury presented with undisplaced lamellar corneal tear which was sutured.

Small tears <2 mm but Seidel’s test positive can be treated with glue and bandage contact lens. But this should not be tried in patients who cannot be followed up regularly and in children (Figure 17).

Small self-sealed tears <2 mm with a well formed anterior chamber and negative Seidel’s test can be left untreated and prescribed antibiotic drops for 1 week. These patients have to be seen the next day and Seidel’s test has to be treated and if there is no further change they can be left untreated.

However in children and non-compliant patients or patients who are not able to come for regular follow up it is better to suture these wounds too.

Large tears (>2 mm) with or without iris prolapse needs to be repaired as early as possible. Once any life threatening injuries are ruled out patient can be taken up for surgery.

Anaesthesia: The anaesthesia depends on the surgeon’s and patient’s preference. In a cooperative patient and a simple corneal tear without any iris prolapse suturing can be done under topical anaesthesia. In a large corneoscleral where exploration is required then general anaesthesia is preferred. But if general anaesthesia cannot be given due to systemic reasons then suturing can be done under local anaesthesia. But care must be taken that the patient does not squeeze his eyes during local anaesthesia injection. To prevent inadvertent pressure on the globe facial block can be given to paralyse the orbicularis muscle followed by peribulbar which can be given in instalments of 2–3 ml initially followed by a few corneoscleral sutures and repeat infiltration can be done as per the need.

Surgical procedure:

• The corneal tear has to be inspected and cleaned and any foreign particle have to be removed.

• If iris tissue is prolapsed into the wound it has to be pulled down. It is better to pull down than push the iris tissue from the wound as the iris tends to prolapse into the wound if it is pushed through the wound. A side port incision has to be made adjacent to the wound and the iris tissue has to be swept away from the wound. Viscoelastic can be used to keep the iris away from the wound. Excessive viscoelastic may result in iris prolapse hence one has to be judicious in its use. (Figure 18)

• Once the wound is cleared of all the foreign bodies and iris pigments it is important to identify the lamellar and perpendicular tears in the wound. The perpendicular/straight cuts have to sutured first as they are the leaky parts. 10-0 or 9-0 nylon suture is preferred with a 3-1-1 tie or a 2-1-1 tie respectively. Once the straight cuts are sutured the lamellar cuts fall in place and the wound remains well apposed and it becomes easy to suture.

• The landmarks such as limbus, and pigment lines or apices of the tear have to be aligned and sutured first.

• One should make sure that adequate number of sutures are placed to ensure a watertight seal. One should not be too enthusiastic in applying sutures as these sutures are potential source of scar and astigmatism on the cornea and only as many as necessary have to be applied. (Figures 19–22)

• It is very important to bury the knots at the end of the surgery as an unburied knot can cause irritation and can be a source of mucus accumulation and infection of the wound.

• If the lens capsule is breached one should not attempt to extract it out from the corneal wound. The corneal tear has to be sutured and the cataract removal has to be performed from a limbal wound. Placement of IOL is arguable as the correct calculation of IOL power is impossible. It is better to place IOL as a secondary procedure.

• In case of stellate tears there are many procedures described such as Eisen’s method and Atkins method but however if one is not able use these methods, a simple cross stitch across the stellate tears would be sufficient.

• In case of tissue loss sometimes a patch graft might be required to form the anterior chamber. If suturing is not possible then one may have to use a combination of suturing and glue but tight pulling of the tissue which causes distortion of the anterior chamber and angle architecture is not advisable.

• The injection of intravitreal antibiotics is also arguable. If the posterior capsule is not breached in the primary injury, it is advisable not to inject any intravitreal antibiotics but if there is a PC rupture of there is evidence of endophthalmitis then intravitreal antibiotics can be injected during the primary procedure.

Figure 18.

Iris prolapse and its subsequent repositioning.

Figure 19.

A small corneal tear involving the superior half of the pupil requires only two sutures.

Figure 20.

An inferior corneal tear sutured.

Figure 21.

A corneal tear repair 1 year follow-up had best corrected visual acuity of 6/9.

Figure 22.

An 18 year old boy who underwent corneal tear repair and cataract removal and IOL implantation in the primary procedure presented with BCVA of 6/12 at 12 months follow up.

Scleral tear repair: Scleral tear is invariable associated with uveal tissue prolapse. It is imperative that one has to be careful while suturing sclera to not include uveal tissue and ensure a meticulous repair as a uveal tissue incarceration is a potential risk factor for sympathetic ophthalmitis. Unlike in corneal wound where the whole wound is inspected and then the wound sutured after identifying landmarks in scleral tear whatever wound is visible is sutured and the rest of the wound is explored. Scleral tears are sutured with 6-0 absorbable vicryl absorbable sutures. The wound is sutured as and when it is revealed until the apex is found. Sometimes the scleral tear extends beyond the equator then it is important to not venture in identifying the apex and one has to stop at the equator as further pull on the globe to expose the wound may cause iatrogenic damage to the globe itself. The conjunctiva over the scleral tear is sutured with 8-0 absorbable vicryl sutures.

Post operative managementof corneal and scleral tear involves

• Topical antibiotics and cycloplegic agents along with systemic antibiotics.

• Topical steroids: Each case has to be assessed and if there is no evidence of infection on post operative day one, then topical steroids can be started and prescribed for a month in a tapering dose.

• The corneal sutures are removed after 6–8 weeks and visual rehabilitation attempted. In paediatric cases the sutures have to be removed much earlier due to faster healing and earlier initiation of visual rehabilitation has to be done.

2.3 Chemical injury

2.3.1 Aetiology

Considered as one of the true ocular emergencies which requires timely assessment, diagnosis and initiation of treatment.

Aetiologies for chemical burns includes: exposure occurring at home or at work place, during incidents with intent of malice such as criminal assaults.

Nature of chemical could be either acidic or alkali—of which, the latter occurs more commonly [13]. Injuries of such nature are known to produce substantial damage to the anterior segment structures like the ocular surface involving the corneal epithelium and limbal stem cells subsequently leading to a permanent visual impairment in one or both eyes depending on the exposure.

The main goal of management is to protect the cornea and to reconstruct the ocular surface to near-normal.

2.3.2 Pathophysiology

2.3.2.1 Alkali burns

Alkalis are known to cause extensive damage as they are lipophilic in nature and thus penetrate the cell membrane easily and cause saponification of fatty acids and thus damages the proteoglycans and collagen bundles present in the cornea. Due to further release of proteolytic enzymes, there occurs a progression of the tissue damage. Therefore, alkalis are considered to be more corrosive.

2.3.2.2 Acid burns

Unlike alkalis, acids act by denaturation and precipitation of proteins of the cornea. This acts by forming a barrier on the corneal surface and thus further damage is intercepted. However, hydrofluoric acid is an exception wherein the fluoride ion has the ability to penetrate the cornea and thereby cause significant anterior segment destruction [14].

2.3.3 Clinical features

The severity of the injury depends on the toxicity of the chemical, period for which the chemical was in contact with the eye, penetration depth, and the areas that are involved. It is crucial therefore to take proper history. If possible, details of the chemical can be checked if patient presents with the packaging-details like composition can be recorded. Nonetheless, all of this should not preclude immediate care to the patient which includes irrigation and removal of any visible retained particulate matter.

After administering required first aid as mentioned above, cursory examination should be done and the depth and severity of injury should be assessed. One should specifically look for conjunctival, corneal and limbal status and the prognosis should be graded accordingly. One of the main goals of stratifying the injuries is to grade the prognosis and to thus choose the most appropriate treatment strategy.

The most commonly used standardised classification is that of Ballen modified by Roper-Hall which has IV grades [15, 16]. Dua later suggested the use of an ‘analogue scale’ which describes the injury in terms of clock-hours of conjunctival and limbal involvement [17]. He also suggested that this scale be used on a daily basis to assess improvement. It becomes important to assess conjunctival status more than limbus involvement because even if the limbus is entirely sabotaged and if sufficient area of conjunctiva remains, it will still be able to re-epithelialize the entire corneal surface and thus prevent perforation of the stroma and can be used as an anchor for limbal stem cell transplantation (LSCT) at a later date if required (Figure 23) [18].

Figure 23.

Analogue scale for classification of ocular surface burns. Adapted from [17].

2.3.4 Management

As a dictum, prevention of exposure to chemicals should always be a priority. If occupational exposure is anticipated, adequate protective measures should be practiced, like wearing protective goggles and shield.

Patients usually present to the Emergency Department the first time with severe pain, excessive watering, spasm of the eyelids and reduced visual acuity.

• Before attempting a complete ophthalmic examination, a pH check is mandatory after which thorough irrigation of the eyes should be performed to bring the pH to a physiologic range around 7.11 ± 1.5 [19]. Copious and prolonged irrigation may be performed with sterile water, Ringer’s lactate, balanced salt solution or any fluid with near neutral pH (for example diphoterine in alkali burns has been recommended) [18]. The amount of fluid required for irrigation is decided by the attainment of near-neutral pH. Irrigation of up to 1–2 l is usually done but sometimes, 20 l or more may be required to combat extremes of pH and to bring it to normal [20]. It is prudent to recheck pH after waiting for at least 5 min after irrigation. One should also be aware of various topical medications—such as topical anaesthesia, mydriatics, antibiotics if administered and its bearing on the pH. For instance tropicamide and cyclopentolate hydrochloride 1.0% are often used for cycloplegia as topical ophthalmic solutions and may have a pH of around 4.5 and 4.0–5.8 respectively. Similarly, proparacaine hydrochloride has a pH of approximately 3.5–6.0 is often instilled as topical anaesthetic drops prior to irrigation to remove any visible foreign body. Certain formulations of antibiotic eye drops also contain HCl to adjust pH like for example, ofloxacin drops is unbuffered and formulated with a pH of 6.4–6.8. More importantly, fluorescein dyes that are sometimes used to assess corneal damage after the initial irrigation is basic in nature and may alter the pH status. Therefore, due to the non-neutral pH of these solutions, the reassessed pH value of the eye might not reflect the true pH [18].

• Injuries of Dua’s Grades I and II will receive a topical treatment consisting of non-preserved tear substitutes that help in re-epithelialisation and also help with the tear film stability, cycloplegic agents like tropicamide or atropine 1% under a topical antibiotic cover, that will help relieve pain and minimise the occurrence of synechiae. It should be kept in mind that the usage of vasoconstrictive agents like phenylephrine should be avoided at all costs to mitigate the risk of limbal ischaemia.

• Injuries of grade III through VI should be admitted and along with the abovementioned treatment, patients should receive analgesics (due to excessive pain caused due to corneal nerve inflammation).

• Topical steroids (prednisolone acetate 1% or loteprednol etabonate 0.5%) is indicated every hour. They act by stabilising the lysosomal and the cellular membranes of neutrophils and thus prevents secondary destruction of tissues around. However, they also slow down epithelialization after a week, therefore it should be used only in the acute phase and should be discontinued thereafter and be reincorporated after 5–6 weeks to minimise chronic ocular surface inflammation [21].

• In patients with excruciating pain, Amniotic Membrane Transplantation (AMT) can be attempted [21, 22]. As Amniotic Membrane (AM) is rich in transforming growth factor β1 and β2 (TGF β), hepatocyte growth factor (HGF) and epithelial growth factor (EGF) and helps in hindering fibrosis formation and promotes epithelialization. For maximum utilisation of these epitheliotropic properties, AM should be used as a patch of appropriate size with the epithelial side down covering the defective area and also in touch with the limbus. Another advantage is that AM acts as an anchor for LSCT if needed in future.

• Injuries of grades V and VI with necrosis of conjunctiva and limbal ischaemia, the necrotic area of conjunctiva is denuded and the underlying tenon’s is advanced in order to cover the defect and to prevent a scleral perforation. In cases with limbal stem cell defect (LSCD), simple limbal epithelial transplantation (SLET), also called in-vivo expansion and cultivated limbal epithelial transplantation (CLET), also called as ex-vivo expansion, can be performed. In-vivo expansion can be obtained from three sites namely: from the innermost area adjacent to the cornea, middle limbus, and from the area located outermost and adjacent to the conjunctiva. Similarly, ex-vivo expansion is obtained from the oral mucosa [23, 24, 25].

• The last resort being possibly keratoplasty and keratoprosthesis can be employed to help restore vision.

2.4 Thermal injury

2.4.1 Aetiology

Ocular burn injuries are a relatively uncommon presentation in the emergency department (ED). Ocular thermal injuries constitute only 7% of all the ocular trauma. 15% of the facial burns patients have associated ocular burns and usually thermal injuries are not severe and very rarely do they cause vision loss [26].

Ocular thermal inuries have been reported to occur due to vegetable oil, fireworks, electric arc, e-cigarette explosion and flash burns. Chemical injuries are usually associated with thermal injury too [12].

2.4.2 Clinical features

Ocular thermal injuries are usually less severe due to the blinking reflex and Bell’s phenomenon (palpebral oculogyric reflex). Cornea may show some charred epihtleium which requires to be removed with a cotton bud after instillation of paracaine drops. Once the charred tissue is removed usually an underlying stromal edema is seen. Epithelial defect can be assessed with fluorescein staining. The corneal stromal edema usually resolves within a few weeks and the cornea clears.

2.4.3 Management

Topical steroids have to be instilled for the first 7–10 days like in chemical injuries as it is important to control inflammation in the initial period. Lubricating drops have to be prescribed.

3. Conclusion

Acute management of anterior segment injury requires a detailed examination and a meticulous repair as the primary surgery has a lasting impact on visual rehabilitation. Systematic examination and preparedness to handle all possible injuries and a surgeon trained in handling all anterior segment injuries is of paramount importance to achieve good vision in these trauma patients.

Conflict of interest

None.