Deep lamellar keratoplasty with complete removal of pathological stroma for vision improvement

EDITOR,—Ocular trauma is recognised as a major cause of visual impairment. Though estimates of incidence vary, it clearly constitutes a major worldwide health problem. The majority of injuries are sustained by active and productive individuals with inevitable consequences on their future lifestyle and on society as a whole. Blunt ocular trauma or “closed globe” injury caused by compressed air blasts resulting in substantial ocular damage 4 is well recorded. However, since much of the literature relates to battlefield explosions, it is often diYcult to prove that no other agent was involved. More recently, injuries from automobile air bags have been described. Such injuries are ascribed to the high velocity at which the air bag lining strikes the occupant (up to 320 km/h) and to objects trapped between the eye and air bag, often spectacles. In discussions with one local balloon manufacturer, it was identified that a number of complaints are made each year to manufacturers regarding incidents involving party balloons, the majority of which relate to incidents that occur while playing with or misusing balloons. As far as we are aware, however, no injuries are reported to have resulted from direct trauma to the eye from the balloon. We have recently seen three patients from the Wessex region who suVered significant closed globe ocular trauma following the bursting of such balloons and are aware of a fourth case where litigation was involved. The first patient, a 48 year old woman with no previous ocular or medical history, suffered closed globe ocular injury to her right eye when the long thin party balloon she was blowing up by mouth exploded. She was not wearing glasses at the time. She presented to the eye casualty department within 3 hours with a painful red eye when the findings were a Snellen visual acuity of 6/24, multiple superficial corneal abrasions, a 3 mm hyphaema, traumatic uveitis and mydriasis, two focal points of iris sphincter rupture, inferior iridocorneal angle recession on gonioscopy, and inferior commotio retinae. Her initial management was with a short course of steroid, mydriatic, and antibiotic drops. Two years later, secondary anterior and posterior subcapsular lens opacification (Fig 1) is apparent, reducing her vision to 6/9. She is troubled by glare and has persistent anisocoria. As yet, cataract extraction is not felt to be justified. Secondary glaucoma has not developed nor have any retinal complications. Her other eye remains normal with 6/4 vision. The second patient, a 34 year old man with no previous ocular or medical history, suffered closed globe ocular trauma to his right eye when the round party balloon he was inflating by mouth exploded. He was not wearing glasses at the time. He presented to the eye casualty department within 24 hours where the findings were a Snellen visual acuity of 6/12, ecchymosis of the upper lid, corneal abrasions, a 2 mm hyphaema, inferior iridocorneal angle recession on gonioscopy, phacodonesis, traumatic uveitis, and inferior commotio retinae. His initial management was with a short course of steroid, mydriatic, and antibiotic drops. One year later, secondary posterior subcapsular lens opacification is apparent, reducing his vision to 6/9. As yet, cataract extraction is not felt to be justified. Secondary glaucoma has not developed nor have any retinal complications. His other eye remains normal with 6/5 vision. The third patient, a 54 year old man with no previous ocular or medical history, suVered closed globe ocular trauma to his right eye when the party balloon he was inflating by mouth exploded. He was not wearing glasses at the time. He presented to the eye casualty department within 2 hours where the findings were a Snellen visual acuity of 6/12, superficial corneal abrasions, a microhyphaema, inferior angle recession, and commotio retinae. His initial management with a short course of steroid, mydriatic, and antibiotic drops. At 6 months, secondary posterior subcapsular lens opacification is apparent, reducing his vision to 6/12. As yet, cataract extraction is not felt to be justified. Secondary glaucoma has not developed nor have any retinal complications. His other eye remains normal with 6/5 vision. A further case was reported by a nearby unit with similar injuries and which has resulted in civil litigation and as a consequence, full details were not available for scrutiny. There are many reports of air blast injuries resulting in ocular injury of which those involving automobile air bags are the most recent. In many cases, however, it is diYcult to be certain that no other agents are involved. Indeed, animal experiments and battlefield surveys suggest that the blast is rarely the cause of intraocular injury but rather the missiles created by the explosion. Animal studies have shown that the only consistent ocular injuries that occur from high blast pressures are those of retrobulbar and subconjunctival haemorrhage. This is presumably due to the even distribution of the concussive force. In the case of automobile air bags, some injuries result directly from the inflation of the intact bag. But in some, contact with the chemicals used to produce inflation (sodium azide) or objects propelled at the eye or trapped between occupant and air bag, such as spectacles, are the cause. Balloons remain a popular party decoration with new and often more adventurous designs. It is also the authors’ impression that long balloons are more frequently used which involve a greater initial inflation pressure. Failure to use an appropriate inflation device may have contributed to the subsequent injuries. The basis for the injuries that we have reported, however, has yet to be determined. However, with all these considerations in mind, four mechanisms can be proposed for ocular trauma in our series. (1) A sudden release of an air jet from the bursting balloon towards the eye could produce an air blast injury. (2) A jet of air could propel the balloon into the eye by retropulsion. (3) The elastic coating may recoil forcibly towards the eye as it contracts, which is more likely with long thin balloons. The direction of the recoil will depend on the location of the tear at the point of bursting. (4) A combination of the previous three. Since the pressure within a typical balloon is relatively low (estimated to be 30 mmHg above atmospheric), it is unlikely that the kinetic energy of the released jet of air would be forcible enough to produce injury directly as seen experimentally of by retropulsion. Furthermore, the localised ecchymosis seen on the upper lid of patient 2, would support a focal contusion at that point, rather than an evenly distributed blast and is more consistent with injuries seen on the battlefield. It is most likely, therefore, that the recoiling balloon coating or the unexpanded tip produces the corneal abrasions and the intraocular damage suVered. It is the authors’ belief that manufacturers should now warn of the hazards of inflation by mouth and initiate strategies to avoid injury— for example, recommending the use of inflation devices or eye protection while inflating a balloon.