MYTHS AND TRUTHS ABOUT EYE INJURIES: ANSWERS TO COMMONLY ASKED QUESTIONS

In the management of ocular injuries, there are numerous examples of controversy. These controversies are gutturally argued at meetings and in the editorials of professional journals. The ophthalmologist’s particular viewpoints are based, in large part, on the opinions of peers taught during residency training, rather than on solid scientific data. These viewpoints are stored in our brains and are inseparably under the influence of our feelings toward our mentors and teachers. In recalling such information, the clinical “fact” is intertwined with emotional memories, tainting it with righteousness. Separating fact from myth is particularly difficult given this emotional baggage. The study of ocular injuries has been particularly devoid of good scientific data to support many of our management decisions. This opens the door to speculation and the propagation of myth.

In the last decades, a number of investigators have attempted to answer many of the controversial points rationally. Although the data supporting some of these decisions may be fallible, they give the physician some guidance and are an improvement over the argument, “well that is how we have always done it.” Throughout this book, the authors have attempted to support their clinical management decisions with scientific data rather than dogma. In the next few paragraphs we question a few of these controversial (if not dogmatic, axiom-like) points as the knowledge gained over the last several years has helped us understand that just because something has been in practice for a long time does not mean that it is correct or acceptable. We divided the list of myths into two categories, based on whether they are the primary concern of the ophthalmologist or of the patient.

THE OPHTHALMOLOGIST

MYTH: NLP vision at the time of presentation following open globe injury is synonymous with permanent blindness.

FACT: Useful vision can be recovered even when NLP vision is documented on proper preoperative testing with a bright light source (see Chapter 8).

MYTH: If only minimal function can be restored to an eye after an injury and reconstruction may take several surgical sessions, it is better to leave the eye alone and not invest effort, time, and resources by offering intervention with so little to gain from it.

FACT: The eye belongs to the patient, who must make the decision whether he or she wants the inconvenience of intervention(s) or the finality of blindness. Counseling therefore must be unbiased rather than one-sided; counseling must present what the options available for the patient are rather than what the ophthalmologist thinks the patient should do.a

MYTH: All of the damage occurs at the time of impact during severe ocular injury, limiting the ophthalmologist’s ability to affect the visual outcome.

FACT: Following open globe trauma, the healing response may result in additional tissue injuries and the eye may deteriorate from excellent visual potential to becoming phthisical. Contusion injury probably results in a similar series of events, although this has not yet

a Remember that Murphy’s law is all too commonly true: if another disease strikes in the future, it seems to prefer the fellow eye. Having even minimal vision in the injured eye might make all the difference for the patient (see Chapter 6).

been investigated in as much detail as the Ryan-Cleary model. Extrapolating from CNS models of contusion trauma would suggest that additional injury occurs as a result of the release of neurotransmitters.

MYTH: Following injury by a blunt object, it is preferable if the eye opens (rupture) than if not (contusion) because the energy is released in the former case, as evidenced by the lower incidence of choroidal rupture in ruptured as opposed to contused eyes.

FACT: While the incidence of certain tissue lesions may be lower in ruptured eyes than in those sustaining contusion, the overall anatomic damage is much more severe and the functional outcome much worse in ruptured eyes (see Chapter 27).

MYTH: Traumatic corneal abrasions require patching to speed the healing process.

FACT: In most cases, the corneal epithelium heals well without patching; in fact, patching may be counterproductive (see Chapter 14).

MYTH: Following severe ocular injury, it is recommended that the patient be patched bilaterally to reduce ocular movement and further injury.

FACT: There is no information to support this policy. In fact, patching both eyes in patients with a unilateral ocular injury will only increase their anxiety and fears about going blind. Only the injured eye should be shielded.

MYTH: A breach in the lens capsule invariably necessitates the removal of the lens.

FACT: Even if the injury results in violation of the peripheral lens capsule and an intralenticular foreign body is present, the developing cataract may remain localized and stationary so that the central lens is clear (see Chapter 21).

MYTH: Dense vitreous hemorrhage following open globe injury can be followed with close observation.

FACT: Vitreous hemorrhage is a key ingredient in the initiation and propagation of intraocular proliferation. Vitrectomy in the first few weeks following primary repair can interrupt this process and reduce the chance of retinal detachment and hypotony (see Chapter 23).

MYTH: Retinal breaks associated with sclopetaria require treatment with laser or cryotherapy to prevent retinal detachment.

FACT: Only rarely do retinal breaks associated with sclopetaria result in retinal detachment, and in most cases the eyes can be followed with close observation (see Chapter 23).

MYTH: Applying blind cryopexy over a zone III (see Chapter 2) injury helps prevent retinal detachment.

FACT: There is no evidence to support that blind cryopexy can prevent retinal detachment, but there is

ample evidence that blind cryopexy can stimulate cellular proliferation and thus increase the risk of PVR (see Chapters 8, 23, and 24); it is therefore contraindicated to apply cryopexy unless performed under visual control.b

MYTH: To be on the safe side, posterior retinal breaks are better treated with some type of “pexy.”

FACT: If the vitreous (i.e., traction) has been removed or severed around the area of the posterior retinal break, “pexy” is usually not necessary (see Chapter 24). Conversely, if the break is anterior, treatment is necessary to prevent the development of retinal detachment (see Chapter 23).

MYTH: Orbital floor fractures invariably require surgical repair and this should be done as soon as possible.

FACT: Many orbital floor fractures do not result in significant enophthalmos or diplopia and thus do not require surgical repair. Early repair of an orbital fracture when there is associated intraocular injury (i.e., posterior scleral wound) may result in additional iatrogenic trauma and should be deferred (see Chapter 36).

MYTH: Orbital foreign bodies are best removed to avoid secondary complications.

FACT: Removal of a deep orbital foreign body may cause more complication than retaining the object (see Chapters 30 and 36). An individual decision, carefully taking into consideration all risk factors, is necessary.

MYTH: An eye that is blind (i.e., has NLP vision) following open globe injury runs a significant risk of inciting SO and thus enucleation should be recommended.

FACT: With modern techniques of primary and secondary globe reconstruction, the incidence of SO is extremely low. For cosmetic and especially psychological considerations, most patients may be better served by retaining the eye. Extensive counseling and close follow-ups are necessary (see Chapters 8 and 31). Patients who do develop SO appear to respond favorably to steroid treatment in most cases.

MYTH: Experienced ophthalmologists understand each other even if they do not use BETT.

FACT: The language of ocular traumatology has nothing to do with experience. Without describing/ typifying/categorizing an injury in a standardized fashion,c it is impossible to know whether a colleague

bEven in such cases, laser is preferred to cryopexy (see Chapters 8 and 23).

cThe lack of standardization was the cause of one of the greatest ironies of our time: a spacecraft that successfully traveled hundreds of millions of miles only to crash at the last minute because some in the control room thought they were using the metric system while others used feet to measure the distance.

appreciates the description as intended. If “rupture” substitutes for all open globe injuries, how does one distinguish an injury that is truly a rupture? If an author uses the term “penetrating” in the article’s title but indicates the term “perforating” as the key word, how should the reader determine what type of trauma is discussed?

THE PATIENT

MYTH: If vision in one eye (or the eye itself) is lost, the fellow eye gets “overused” and “strained.”

FACT: The “workload” of one eye is independent of that of the fellow eye, just as the loss of one kidney does not exhaust the other kidney. Just because of becoming monocular, there is no need to change one’s lifestyle in terms of the time spent on reading or watching television; but the person should consciously try to reduce the risk of injury to the remaining eye (i.e., wearing ocular protection as appropriate).

MYTH: Physical activities should be severely restricted if the patient suffered a serious eye injury.

FACT: There is no evidence to support this theory. The cause of post-traumatic retinal detachment is an unrecognized retinal break or the development of PVR, not jogging or lifting weights (see Chapter 27).

MYTH: Following open globe injury or severe closed globe injury, the patient should be counseled never to play sports again.

FACT: In reality, we do not have factual information to support this recommendation. Patients should be counseled in all cases about the importance of proper safety glass usage (see Chapter 27) and their legal implications (see Chapter 7). Likewise, little information exists to determine, with certainty, when it is safe to return to such activity following an injury.

MYTH: Deployment of an air bag during an MVC commonly results in severe ocular injury, supporting the argument that airbags should be deactivated.

FACT: Ocular injury during an MVC is 2.5 times more likely to occur if there is no air bag deployment. Air bags significantly reduce both the mortality and morbidity, even if occasionally they may be the cause of certain injuries.d Disengagement should be considered only in certain unique and specific circumstances (see Chapter 27).

MYTH: Unless the visual acuity drops to 20/50 in a patient with traumatic macular hole,e there is no indication to perform surgery.

FACT: There is no specific visual acuity that can be justified as a valid cutoff value. It is the patient’s responsibility to determine whether the visual function allowed by the condition is sufficient. It is the ophthalmologist’s responsibility to offer unbiased and reasonably accurate information regarding the risks and benefits of the procedure versus those of observation (see Chapters 5 and 8).

MYTH: Lacerations involving the upper canalicular systems do not need to be repaired since they do not play a role in the transport of tears.

FACT: In certain people the upper canalicular system plays a more important role in tear transport than the lower canalicular system. Because it is impossible to determine which of the two is more important in the injured person, the upper lid’s laceration must also be properly repaired (see Chapter 35).

Future, well-designed studies of ocular injury will help us continue to debunk additional myths and offer better treatment recommendations to our patients. Ophthalmologists must keep an open mind and regularly analyze their own practice patterns to determine whether these hold up to the truth (e.g., evidence) or are just myths.

dIn many cases, the reported link between air bag deployment and injury is assumed and has not been supported by evidence.

eThe same can be said regarding other conditions (e.g., cataract, EMP).

Ophthalmologists agree with the conclusion of the National Research Council that “Injury is probably the most under-recognized major health problem facing the Nation today.” As the physicians who treat and see the consequences of trauma, U.S. ophthalmologists— working with the Safety Committee of the American Academy of Ophthalmology—are making a concerted effort to educate all eye care professionals and the general public as to which activities pose a risk for significant eye injury and how best to minimize the risk.

The following data were taken from the USEIR, and will be discussed in light of data gathered from a sampling of emergency rooms by the United States Consumer Products Safety Commission, through

NEISS. The NCAA injury rates (Table A7–1) apply only to sports played in participating colleges.

STUDY 1

The USEIR database contains 10,309 cases of serious eye injury from December 1988 to September 1999. Our analysis found the following.

•Sex: male 8284, female 1938, unknown 65, not stated 22.

•Bilateral: yes 757, no 9450, not stated 102.

•Open globe: yes 4798, no 5511, not stated 0.

•Bystander: yes 1626, no 5413, unknown 1185, not stated 2085.

•Eyewear: none 6359, regular 275, safety 144, sun 28, unknown 1321, other 24, not checked 2158.

•Place of injury: industrial 1278, farm 244, home 3888, school 255, place for recreation and sport 1261 (12%), street and highway 1299, public building 297, unknown 888, other 256, not stated 643.

•Intent: assault 1375, self-inflicted 90, unintentional 6385, unknown 509, not stated 1950.

•Source: hammer on metal 510, sharp object 1842, nail 565, blunt object 3148, gunshot 414, BB/pellet gun (includes paintball) 574, motor vehicle crash 954, fireworks 501, burn 236, explosion 296, lawn equipment 201, unknown 106, other 378, not stated 584.

•Region: Northeast 280, Southeast 5773, Midwest 2525, Southwest 809, West 846, Other 76.

STUDY 2

Because ASTM F8.57 is concerned with standards for sports, the USEIR injuries for sports and recreation were analyzed separately. Sufficient detailed data were present in 702 of the 1261 cases (56%). The welldocumented 702 cases were studied in detail as a subset with the pertinent data imported for analysis into Data Desk. The results of the 702 cases are summarized in Table A7–2.

Of the 46 patients known to have been using eyewear at the time the injury occurred during sports and recreation, the eyewear shattered, often lacerating the globe, in 16 (35%). Eyewear use was none 400, unknown or not stated 256, regular 35, safety 6, and sun 5.

The Protector Standard column of Table A7–2 specifies the standard for eyewear that most likely would have prevented the injury. The+after ANSI Z87.1 in bungee cords refers to protectors that pass the high mass and high velocity sections of the standard. For such common sources of eye injury, as fishing, hunting, and golf, there are no standards. It is precisely for these sports with high risk of severe eye injury, and for which users would find protectors that meet the specifications of ASTM F803 too bulky, that the new ASTM moderate impact standard is intended. Note that 44% of fishing injuries, 47% of hunting injuries, and 41% of golf injuries are open globe. The high incidence of blinded eyes in fishing (30%), hunting (47%), and golf (41%) shows the need for appropriate eye protection and education in these sports. Table A7–3 shows the test energy specified in various standards.

STUDY 3

All cases in the entire database (n=10,309) who were known to have been wearing eyewear (n=440a) at the time of injury were analyzed. In Table A7–4 “yes” means that definite shatter was specifically stated. “Probable” shatter was evident from the mechanism of injury and the actual injury. The shatter percentage (“yes” plus “probable”/total) was regular 20%, sun 18%, and safety 7%. Shattered eyewear accounted for over one sixth of the serious eye injuries to people wearing eyewear at the time of impact.

STUDY 4

Wound dehiscence is a major concern to ophthalmologists. 2.5 to 5.7% of patients who have had a PK can

aThis differs from n=471 (regular 275, safety 144, sun 28, other

24)in study 1 because 31 of the cases in study 1 had inadequate information for inclusion.

expect traumatic dehiscence of the wound, on average 3.4 years after the PK but with no “safe” time (see Chapter 27). It is well recognized that the eyewall regains only approximately 50% of the original tensile strength when incisions have healed. An analysis of USEIR wound dehiscence data showed that, of the 126 cases of wound dehiscence in which eyewear use was known, 24 (19%) were wearing glasses (21

streetwear, 2 sunglasses, 1 safety glasses) and still developed globe rupture.

STUDY 5

The NEISS data that reflect approximately the same categories of sports and recreation injuries in the USEIR data are presented in Table A7–5.

STUDY 6

The SGMA estimates of sports participation are presented in Table A7–6.

OBSERVATIONS AND CONCLUSIONS

1.When compared with the NEISS eye injury estimates, it is apparent that the USEIR captures approximately 0.3% of sports and recreation eye injuries (about 400,000 sports/recreation injuries over 10 years in NEISS, about 1300 sports/recreation injuries reported to USEIR). The databases supplement each other. NEISS gives national trends based on emergency room sampling, but the data are not detailed. USEIR is a slice of serious injuries treated by ophthalmologists for which detailed information is available. Because NEISS does not sample ophthalmologists’ offices or eye hospitals, serious eye injuries, such as open globe injuries that go directly to the ophthalmology tertiary care center, this trauma is underrepresented in the NEISS database.

The USEIR database has low representation from the Northeast and high representation from the Southeast, with one state (Alabama) having 4924 cases. The 47.8% representation of Alabama injuries may somewhat skew the injury data away from winter sports and more toward warm weather outdoor activities.

2.The NEISS data presented in Table A7–5 show that eye injuries are commonly related to eyewear. The eyewear numbers represent the entire NEISS database and are not limited to sports and recreational activities. A detailed analysis is not possi-

TABLE A7–6 SGMA SPORTS PARTICIPATION TRENDS: U.S.

POPULATION 6 YEARS, AT LEAST ONCE IN 1977 (MILLIONS)

ble from the NEISS data at this time, but eyewear failure is a definite problem and requires more indepth analysis.

3.USEIR data show that common sports-recreational activities, such as fishing, hunting, and golf, are associated with severe eye injury. There is no eyewear standard for these and other moderate impact sports such as frisbee and miscellaneous ball sports. Eyewear conforming to the moderate impact standard requirements can eliminate or decrease the severity of most moderate impact sports eye injuries. It must be realized that golf has such high impact energy concentration that moderate impact eyewear will permit contact of the protector to the eye. Hunting, mountain bicycling, and other sports also have the potential for extreme impacts, which will exceed the requirements of the proposed standard. The user will have more protection using high impact eyewear that conforms to ASTM F803, but complete protection from all possible hazards is not possible.

4.Shattered eyewear lenses and frame failure are relatively frequent causes of open globe injuries in moderate impact sports and recreational activities.

5.Postoperative wound dehiscence is common despite eyewear use at the time of injury. In order to protect eyes that are prone to rupture, it is necessary to have a lens that will not shatter held in a frame that has the ability to retain the lens and prevent contact with the eye.

6.The NEISS data are discouraging. We know that there has been a definite reduction in hockey injuries to players who wear protection. Hockey has an ASTM standard for protection, HECC, and the mandatory requirement for protector use in over 1 million players. There are now over 21 million player-years of HECC certified protector use without any significant eye injuries. Yet, as shown in Table A7–5, many hockey (ice, field, street) players still play without protection and suffer injuries.

impact eye hazard. A massive consumer and professional education program is essential. Sports with a high risk for eye injury, for which there is available certified protection, should have protection strongly recommended or mandated by sanctioning bodies; a good example is paintball.

9.The data support the need for a moderate impact standard for moderate impact sports. Eye care professionals may also specify eyewear that conforms to this standard as streetwear for patients who are functionally one-eyed or who have surgical or medical conditions that predispose to rupture of the eyewall.

SUGGESTED READING

Jeffers J. An ongoing tragedy: pediatric sports-related eye injuries. Semin Ophthalmol. 1990;5:216–223.

Parver LM. Eye trauma: the neglected disorder. Arch Ophthalmol. 1986;104:1452–1453.

Schein OD, Hibberd PL, Shingleton BJ, et al. The spectrum and burden of ocular injury. Ophthalmology. 1988;95: 300–305.

10.ANSI Z80 and ANSI Z87 specifically state, in the scope of the standards, that they are not intended for sports. The can-of-beans test clearly displays that the test energies required to pass these standards are inadequate for most sports with the potential for moderate impact. The proposed ASTM moderate impact standard fills the gap between the ANSI standards and the high impact ASTM F803.

11.Eye care professionals and users are confused about eyewear appropriate for specific activities. A clear delineation of a spectrum of eyewear standards with an educational program should increase the awareness and use of protective eyewear and lead to a reduction in preventable injuries.

Vinger PF. Eye safety testing and standards. Ophthalmol Clin North Am. 1999;12:345–358.

Vinger PF, Woods BA. Prescription safety eyewear: impact studies of lens and frame failure. Optometry. 2000;71: 91–103.

Vinger PF, Parver L, Alfaro DV, Woods T, Abrams BS. Shatter resistance of spectacle lenses. JAMA. 1997;277:142–144.