Today's news from the 2010 APAO meeting brought to you by EyeWorld magazine.




Meeting Reporter is sponsored by Alcon

Preventing corneal graft rejection

Over the last 15 to 20 years, the survival of major organ transplants has improved significantly. Unfortunately, the same can't be said of corneal transplants. The problem is that the pharmacological immunosuppression that has been the mainstay for preventing rejection in major organ transplants has too many serious adverse effects to justify use for preventing corneal graft rejection, which, strictly speaking, isn't a life-threatening condition, said Sonja Klebe, M.D., in a lecture on molecular interventions in corneal graft rejection delivered at a symposium on the hottest topics in ocular pathology held Sunday. As a result, the approach to preventing corneal graft rejection has generally revolved around modifying surgical technique.
The success of corneal transplants is largely contingent on the survival of the endothelium, upon which the clarity—and therefore the primary function (i.e., light transmission)—of the cornea is dependant. What makes improving graft survival particularly tricky is that in humans, unlike in some animal models used in the lab, the corneal endothelium is a non-replicative tissue.
The last few years have seen the development of modified transplant techniques (such as the various lamellar keratoplasties) and the invention of devices (such as endoglides) to minimize potentially damaging manipulation of donor endothelium. These techniques and devices do appear to have improved the survival of low risk grafts (i.e., those performed to address conditions like keratoconus and stromal dystrophy); however, the real problem, said Dr. Klebe, is survival in the high risk cases, usually involving previous graft failure and neovascularization in the recipient bed.

SICS vs. phaco

No one can question the value of phacoemulsification technology in cataract surgery. However, in developing countries, manual small incision cataract surgery (SICS) continues to have a "big role," said Ravindran Ravilla, M.D., Aravind Eye Care System, India. The procedure, he said, is most suitable for the advanced, hyper-mature cataracts seen in rural areas around the world that generally cannot be dealt with using phaco, or at least not without causing some degree of endothelial damage. Dr. Ravilla chaired a symposium Saturday which focused on SICS techniques.
Globally, around 18 million are "really blind" with visual acuities of 3/60 or worse, said Sanduk Ruit, M.D., Tilganga Institute of Ophthalmology, Nepal. Expanding the definition of cataract blind to include people with relatively better visual acuities of 6/60 and 6/18 increases the number three- and eight-fold, respectively. The problem inherent in these statistics is that the "really blind" people are also the ones who are socially, geographically, and economically deprived access to cataract surgery. These people, said Dr. Ruit, exist in a kind of cocoon, enclosed within a shell of cataract patients with better acuities who are able to access treatment. This situation makes "true" cataract blindness a public health issue; this poses specific challenges in terms of cataract surgery technique.
In developed countries, where cataracts are generally dealt with early in their natural history, there is a distinct bias towards phaco. In these countries, phaco is unquestionably considered the standard of care. However, to begin with the technology involved with phaco can be forbidding for developing countries; the logistics alone of bringing the necessary equipment for phaco to the regions of the world where most of the truly cataract blind population live are virtually insurmountable.
A program that uses phaco to eradicate cataract blindness, said Mohan Thazhatu, M.D., of the HelpMeSee organization,  would cost US$130 billion at current prices; an equivalent program using SICS would cost only US$4.5 to 5 billion.

SICS provides a safe, straightforward technique that requires no special equipment other than the most basic instruments of ophthalmic surgery; this alone makes SICS the obvious choice for any serious public health program aimed at eradicating cataract blindness. Some may wonder if cataract patients aren't being shortchanged when surgeons resort to this decidedly less advanced mode of cataract surgery. The answer, according to data presented by Geoffrey Tabin, M.D., University of Utah, is a resounding "No."

In a head-to-head comparison of phaco and SICS, with the techniques performed respectively by David Chang, M.D., and Dr. Ruit to treat 180 "typical cases"—patients with hyper-mature cataracts in Nepal—SICS was comparable in terms of safety. It also showed a distinct advantage in terms not only of cost, but also of ease, time, and visual outcomes in these cases. About 70% of the Nepalese patients who underwent phaco in Dr. Chang's hands achieved 20/60 or better vision; more than 90% achieved 20/60 or better after SICS with Dr. Ruit.

Preventing fireworks eye injuries

Among those with ocular injuries due to firecrackers in India, minors, those hurt by unexploded firecrackers, and those injured by falling rockets experienced the worst visual outcomes, according to a congress poster presented by Sanjoy Chowdhury, M.S., D.O., Senior Deputy Director, Bokaro General Hospital, India. In one study of 82 eyes of 66 patients admitted between 2000 and 2005 for fireworks-related eye injuries in one hospital in India, 60% were hit by rocket-type firecrackers and the mean age was 14 years. Ten percent of eyes experienced severe injuries "mostly due to falling rocket stick and unexploded crackers," the poster reported.
Dr. Chowdhury noted that this type of injury is the most common cause of monocular blindness. Dr. Chowdhury suggested that four different methods could help reduce this type of injury, including banning fireworks, raising community awareness, modifying the nature of the hazard, and seasonal prevention (which the poster highly recommended). "As most injuries had seasonal preponderance, preventative activity should be intensified during these periods," Dr. Chowdhury reported.
Dr. Chowdhury also listed seven other preventative measurements, which he considers to be "ideal." They are as follows:

  • Only attend fireworks displays put on by professionals
  • Avoid letting children of any age play with fireworks
  • Don't touch unexploded fireworks; Call the police or fire department to remove them
  • Wear protective eyewear when in the vicinity of fireworks
  • Take note of wind changes when in the vicinity of fireworks
  • Do not experiment with "homemade" fireworks.
  • Keep water handy in case of fire or fallen fireworks debris.

Dr. Chowdhury also shared U.S. data on fireworks injuries, which have been studied rigorously, to offer further insights. Eyes are involved in 20% of fireworks injuries, with bottle rockets accounting for 2/3 of them. A third of the eye injuries result in permanent blindness. "Half of those who receive eye injuries are simply bystanders," Dr. Chowdhury reported. Children who are left unsupervised also are 11 times more likely to receive fireworks injuries. Unfortunately, injuries involving firecrackers also are more than visually threatening; they're also life threatening. "In 1999, nineteen people died from fireworks-related injuries," Dr. Chowdhury reported.

Early intervention for visually impaired children needed

Visual impairment in children negatively affects a variety of functions, including communication, interaction, motor functions, spatial concepts, object permanence, orientation in space, incidental learning, and language, according to Lea Hyvarinen, M.D., Ph.D., Technical University of Dortmund, Finland. "With appropriate early intervention, the development of visually impaired infants/children can be kept close to normal development milestones," Dr. Hyvarinen reported in a congress poster.
In order for this to happen, Dr. Hyvarinen recommended a series of steps, including:

  • Detection of structural abnormalities of the eyes and cataract at birth (in particular by checking red reflex)
  • Detection of deviations in normal early communication and interaction
  • Correction of large refractive errors without delay
  • Detection of delays in motor development, head control, and reaching for and grasping objects
  • Detection of delay in visual recognition of family members while recognizing their voices
  • Special screening of children with cerebral palsy and intellectual disabilities

Once visual impairment is determined, selected hospital nurses can train mothers/fathers to support the child's development, Dr. Hyvarinen reported. "Nurses can also function as liaisons to local federations or associations of the blind, facilitating a connection to continuing services and contact with families of visually impaired infants and children." Although the early months of visually impaired children are important in terms of supportive instruction, the need for assistance continues. "The need for support continues through other potential crisis times such as the start of kindergarten and school," Dr. Hyvarinen reported.

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