What are Macular Holes?

The macula is the small area in the center of your retina that is full of light-sensitive cells called cones. These cells are responsible for providing color vision, and allows for the recognition of faces and other objects. The rest of your retina – the area surrounding the macula – contains rods, photosensitive cells that provide black-and-white shading, and allows your side (peripheral) vision to detect movements and shapes.

If a hole develops in your macula, your ability to see objects head-on can quickly become compromised. Similar to macular degeneration, macular holes are an age-related eye condition that is most common in people over 60 years old. However, unlike macular degeneration, macular holes do not develop as a result of genetics or lifestyle choices. Instead, they are caused by factors such as:

  • Eye injury
  • Diabetes
  • Detached retina
  • Severe myopia
  • Macular pucker
  • Vitreous separation or shrinkage

Macular holes can be treated through a vitrectomy. During this procedure, your ophthalmologist will remove your vitreous gel and replace it with a mix of air and gas that is designed to put pressure on your macula, causing the hole to heal itself. Over time, the gas/air will be gradually replaced by natural eye fluids again, and your vision will be restored.

If you are suffering symptoms of macular holes, please contact an experienced ophthalmologist in your area today to schedule an initial consultation.

Corneal and Conjunctival Impact of Pepper Spray

With the increased use of pepper spray to subdue protestors from coast to coast, the nonlethal weapon is receiving extensive media attention from pundits, and it is worthwhile to take some time to analyze the health effects of pepper spray. Elsewhere people may consider the impact of the spray on respiratory health, permanent alteration of pain response, and possible death. Here we will consider what we know about the impact of pepper spray on the human cornea as well as the conjunctiva.

What we know about possible eye injury from pepper spray seems to be surprisingly limited. The product has never been evaluated by a regulatory body for human health and safety, so accounts of its eye safety remain largely anecdotal, based on very few limited studies on humans and animals. How few studies? Probably less than a dozen looking at eye safety. How limited? The total number of human subjects is probably less than 100, not enough for a single decent study, let alone the basis for declaring any substance “safe.” I say “probably” because I am allowing that my limited research on the NCBI database may have missed some studies, but I only found four studies looking at human corneal exposure, with a total of 62 subjects.

Two studies report the impact of pepper spray on 57 volunteers. According to one study, which used pre- and post-exposure visual exams at 10 minutes, 1 hour, and 1 week. This study found that among its 47 subjects visual acuity was unaffected by pepper spray exposure. Although corneal sensitivity was reduced at 10 minutes and 1 hour, it had returned to baseline by 1 week after exposure.

A second study looked at the impact of pepper spray on 10 volunteers. It also reported that the corneal response to a first exposure to pepper spray is primarily temporary swelling of the cornea’s outer layer, with no impact on the cornea or its nerves, though tear fluid showed increased levels of nerve growth factor, showing that nerves were responding to the stress, though sprouting of nerves was not observed. However, one volunteer did lose one line of best corrected visual acuity. This study concluded, however, that a volunteer who had been exposed to pepper spray before showed an unusual arrangement of nerve fibers.

In both of these studies, one week follow-up time is too short to evaluate the impact of pepper spray on the cornea. In many circumstances, such as coronary nerve recovery following myocardial infarction, nerve recovery may begin almost immediately, but studies of corneal healing after LASIK indicate that corneal nerves may not begin to recover until six months after injury.

The other two studies looking at the corneal impacts of pepper spray are evaluations of exposure victims who suffered serious adverse consequences of exposure. One study evaluated four individuals who suffered corneal erosion due to pepper spray exposure. The primary culprit in all four cases was not the oleoresin capsicum, the so-called “pepper,” but the carrier agents. In fact, one victim was exposed to a mock pepper spray with only carrier and no actual oleoresin capsicum. In this study, all four patients showed “a long-lasting, deep corneal and conjunctival erosion,” which resolved partially, but full healing of the cornea’s deeper layers does not generally restore the cornea to its original form (which is what makes LASIK treatment generally permanent). In this study, researchers also used pepper spray on a soft contact lens and plastic cup to demonstrate the erosive effects of the carrier.

The fourth study looked at a 2.5 year old boy who suffered conjunctival proliferation after accidental exposure to pepper spray. Conjunctival proliferation is when the outer layer of the eye sprouts additional growth, such as a pterygium. This growth began three weeks after exposure, and had to be surgically removed. Once removed, the growth did not recur during three months of follow-up.

Although conventional wisdom suggests that pepper spray is largely safe for use in subduing arrest subjects, there is actually little evidence to support this supposition, and certainly enough evidence to suggest that it should be evaluated clinically in larger populations with longer follow-ups to ensure it is actually reasonably safe.

In the meantime, if you have suffered pepper spray in the eyes, you should be evaluated by your eye doctor, even if you do not believe you have suffered any lasting effects.

Most Victims of Aerosol Can Injuries Are Children

The majority of people who suffer eye injury by spraying from aerosol cans into the eye are children, but just barely. Researchers from Brown University looked at emergency room visits for eye injuries related to aerosol cans from 1997 to 2009, and estimate that a total of 10,765 people visited the emergency room for aerosol can-related injuries, of which 5,927 were children age 18 and under.

The age segment with the highest risk for this type of injury was the youngest children, age 0-4 years. These children suffered an estimated 2,830 emergency room visits during the time frame for the study, more than 200 every year. The researchers emphasize that these injuries are preventable, but may have lifetime consequences. Children are attracted to the often pleasant smells contained in the cans and are unfamiliar with the proper operation of the complex mechanism.

Researchers note that their figures may underestimate the incidence of this type of injury. Their estimates were based only on emergency room visits, extrapolating from actual visits recorded at 100 hospitals, but many people may seek treatment at clinics or doctors’ offices.

The most common type of injury was, not surprisingly, self-inflicted spray, due again to the complex mechanism of aerosol cans. However, sometimes people were hit in the eye with chemicals or debris when the aerosol can burst. Males of all ages accounted for 63 percent of those injured, so it is not surprising that spray paint, not hairspray, is the most common product involved. Other products that may be involved included cleaning products and bug sprays. Pepper spray injuries were very rare, but in every case the victim was a child.

The majority of injuries (over 70%) took place in the home. The research team noted a number of potential prevention measures that could decrease the incidence of these eye injuries in children. This included increase the counseling pediatricians gave parents about aerosol cans or asking hardware stores to stock goggles in the same aisle as spray paint cans.

Contact a local ophthalmologist to learn about how to prevent this and other eye injuries in children.