louis vuitton outlet Are airbags a risk for patient

Are airbags a risk for patients after radial keratotomy

Recently, some investigators have expressed concern about the impaired integrity and decreased tensile strength of the cornea

following radial keratotomy (RK) and wound healing, because of pathological findings in human and animal corneas.1 3Corneal tensile strength in eyes following RK has been evaluated in animal models. It has been reported that rabbit corneas

rupture along one or more corneal incisions with or without extension into the sclera.4 In a histopathological study, incomplete healing 2 years after RK has been reported.5 In contrast, there was no significant difference in tensile strength between RK corneal strips and control strips f louis vuitton outlet rom human

cadaver eyes, indicating that the increase in susceptibility to rupture due to RK may be hard to predict and may depend on

factors such as the size of the epithelial plug and the strength of the wound collagen.2 However, after the epithelial plugs are replaced with collagen, there is no assurance that the tensile strength of the cornea

will be more than 50% of louis vuitton outlet the preoperative value, since the only barrier to globe rupture from direct external forces and internal

forces of acutely raised intraocular pressure at the time of impact is the 0.02 to 0.05 mm of unincised corneal tissue, epithelial

plugs, and irregular scar tissue.6

There are documented cases of RK wounds withstanding severe blunt ocular trauma; however, there are also reports of corneas

that ruptured at RK incisions after trauma.67 Another report cites examples of corneal rupture through RK incisions after blunt trauma as late as after 10 years.8 Although the incidence and need for RK have been decreasing for several years because of the introduction and increase of

laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) using the excimer laser, there remain a huge number

of patients who have undergone RK, and the procedure remains a valuable method for correction of moderate myopia, notably

because of its minimal cost.9

Airbags, which have been mandatory in the United States since 1991, are designed to mitigate head and upper torso injuries

to the driver and passenger in frontal crashes of motor vehicles. The efficacy of airbags in the prevention of motor vehicle

related injury and death is well documented.10 Despite the overall protective effect of airbags, they can cause fatal and non fatal injuries if the driver’s head, neck,

chest, or arms are too close to the deploying airbag.1112 Among the most severe airbag associated injuries are those of the ocular region. Although airbag induced ocular injuries

are rare, they still present a serious concern because louis vuitton outlet of the possibility of permanent damage or visual impairment. Gaseous

and particulate components (sodium hydroxide, carbon monoxide) are emitted inside the vehicle at airbag deployment.13 However, skin abrasions and eyelid ecchymoses, the most common facial injuries, are usually short lived, and these chemical

injuries due to airbags have less clinical importance than mechanical trauma. Airbag induced mechanical ocular injuries include

corneal abrasion, corneal laceration, corneal end louis vuitton outlet othelial cell loss, angle recession, hyphaema, cyclodialysis cleft, retinalA case of airbag related corneal rupture in a patient who had undergone RK 2 years previously has been reported.21 This patient was struck in the eye when the driver’s side airbag inflated during a low speed collision. The critical determinant

of severity of ocular injury associated with airbag deployment appears to be the aggressiveness of the airbag. The industry

average for the deployment velocity of an airbag is 64.5 m/s and calculated deployment velocities range between 50 and 113

m/s.22 They inflate in about 10 ms in response to sudden longitudinal deceleration and deflate within seconds.

We have previously developed a simulation model of the human eyeball based on information obtained from cadaver eyes, using

a specific software program for a computer,23 and applied to it simulated airbag ocular injury to determine the physical and mechanical conditions of the impacting airbag