Originally published in The Ottawa Citizen, July 25, 2005
Original title: Future Visions Now a Reality

Four exciting good-news medical stories warrant more exposure. Two of the stories report research into restoring the sight of visually impaired people. The other two stories demonstrate ultrasound technology advances to treat prostate cancer and improve medical diagnostic imaging.

The eyes have it.

Researchers at the Centre for Sight, Queen Victoria Hospital, in East Grinstead, West Sussex, spent five years perfecting a technique to restore the vision of patients who suffered severe corneal damage from acid, alkali and molten metal burns or from congenital disorders. These people were told at the time of their injury they had little hope of regaining their sight.

The cornea is the clear “window” covering the centre of the eye. When damaged, it can scar blocking light from passing through the pupil to the retina.

The treatment process involves harvesting stem cells that come from the eyes of donors. The cells, in turn, are grown into sheets. Once the sheet is complete, they are placed onto the surface of the eye and held in place by an amniotic membrane. This special membrane dissolves once the sheet fuses to the eye.

An unexpected outcome of the procedure was that the rejection rate of the transplanted tissue was almost nil. A year after the transplant, DNA analysis of the transplanted tissue showed no trace of the stem cell donor’s DNA; there was no donor tissue left. The recipient’s eyes took over the healing process and repaired the damage. This meant there was no need for long-term use of anti-rejection drugs to suppress the immune system.

Edward Bailey, who suffered a caustic acid injury to his left eye and lost his sight, said the operation has transformed his life. “It was the most emotional moment,” Mr Bailey, 65, said. “I couldn’t believe it. For 10 years all I had seen was shades of black and grey, then after I had the operation, the nurse came by and I saw a flash of blue from her uniform.

“I went home and when I took the patch off my eye, I had my vision back. It is only when you lose something like sight that you realize how precious it is.”

The team is now looking at other avenues to apply this technology to other damaged tissue around the body.

Another sight restoration procedure was reported by scientists from the University of Southern California and the Doheny Retina Institute in May at the annual meeting of the Association for Research in Vision and Ophthalmology. Six patients with retinitis pigmentosa, a progressive degeneration of the light-sensing cells of the retina, were given artificial retina implants or intraocular retinal prostheses.

The retinal prosthesis, developed and created in conjunction with Second Sight Medical Products of California, is a four-by-four grid of platinum electrodes set in a thin silicone rubber sheet about the thickness of Scotch tape. The sheet is implanted directly onto the retina.

The grid remains in constant wireless communication with a small external computer controller that is attached to the recipient’s belt. The image data is sent to the computer via a tiny video camera attached to special glasses worn by the patient. The computer digitizes the image and sends it to the platinum grid. The grid then stimulates the eye’s photoreceptor cells just like the retina once did. The signal is then carried to the brain’s vision centre to process the image.

Although the grid contains only 16 electrodes proving only 16 pixels of resolution (today’s consumer digital cameras typically have three million to five million pixels), patients were able to detect light, identify objects and even tell if an object was in motion.

In 2002, after being blind for more than 50 years, the first patient to receive the implant was able to see large letters and distinguish between a cup, a plate and a knife.

Mark Humayun of Johns Hopkins University, who has a doctorate in bioengineering and surgical training and started this project, will begin the next step to improve pixel density. This year he plans to use an implant that has 60 to 100 electrodes but is a quarter of the size of the original model. He hopes that 200 to 400 electrode models will be available in three years and plans to develop a prototype for a 1,000-electrode implant in five years.

The hope is that these devices will help restore the sight for people with retinitis pigmentosa and macular degeneration.

In the next column, we’ll look at amazing things you can do with ultrasound.

© Dr. Barry Dworkin 2005

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2. The Unofficial Top Medical Stories of 2004
3. Another H1N1 non-story: doses of vaccine wasted

Originally published in The Ottawa Citizen October 8, 2002
Original Title: Daycare Part II: Run, Run, Run, as Fast as You Can

Part I – Why children fight one cold after another
Part III – Childhood rashes hard to diagnose at first

Last week, the effects of the common cold and ear infections topped the list of the more common child and infant infections. School and daycare still have more to dish out.

There are several types of pink eye or conjunctivitis: infectious (bacterial and viral) and allergic.

The infection primarily involves the eyelids and whites of the eyes. The inner lining of the lids become red and inflamed. Depending upon the source of the infection, parents can determine whether the infection is bacterial or viral. Both types easily spread by rubbing the eyes. The infection transfers to the hands. The child then touches another’s hands. When their hand rubs their eye, the infection finds a new home.

Viral conjunctivitis causes the eyelids to redden and occasionally swell. It accounts for ten to 15 percent of all infant pink eye infections. The fluid that leaks from the eye during the day is usually clear and watery. The eyelashes look normal. The whites of the eyes can be a flushed pink with fine blood vessels on its surface.

The eye can feel irritated, burning, sandy, or gritty. The infection usually spreads to the other eye within 24 to 48 hours. In the morning, upon awakening, a yellow crystalline accumulation in the corners of the eyes is common. Often this substance is confused for a bacterial infection. A soft damp cloth can wipe the crusts away.

Anti-inflammatory eye drops will help ease the discomfort. The infection lasts about five days. Children are contagious for the first five to seven days. Antibiotics will not help alleviate viral conjunctivitis. The symptoms generally get worse for the first three to five days, and gradually resolve over the following one to two weeks. Once the discharge stops, children can return to school or daycare.

The bacterial version of pink eye can appear differently. Accounting for 80 percent of childhood pink eye, thick yellow-green-white pus collects on the eyelashes and lid margins and drips out of the eye throughout the day. The area surrounding the eye is usually smeared with crusty yellow dry pus. After a night’s sleep, the child’s eyelids are stuck together because of all the dried discharge. The inner eyelids and the whites of the eye can be very red.

Streptococcus pneumoniae and Haemophilus influenzae are responsible for most cases of bacterial conjunctivitis in children. Treatment consists of antibiotic drops for five days, soft warm damp cloth wipe-downs of the eyes and isolating the child from other children. Children can return to school or daycare one to two days after starting antibiotics.

Allergic conjucntivitis accounts for 2 percent of all pink eye in children. They often have itchy, red eyes without morning crusting or difficulty opening the eyelids. The treatment includes avoiding the allergy causing substance and applying topical antihistamines, or anti-inflammatory drops. The symptoms quickly resolve (minutes to hours) after using the drops.

From runny eyes to runny bums, diarrhea spreads like wildfire. The Norwalk virus causes most school and daycare-based cases. Rotavirus tends to affect infants. Soiling of clothes, lack of handwashing and close physical contact are fertile breeding grounds for this disease.

The Norwalk virus can cause either a mild fever with watery diarrhea or a more severe fever with vomiting, headache, muscle ache and fatigue. Once infected, the virus will incubate about 24 to 48 hours before the symptoms begin. Stomach cramps and nausea are the first to appear starting gradually or hit full force. Vomiting follows thereafter. A low-grade fever of 38.3 to 38.9ºC (101 to 102ºF) occurs in approximately one-half of cases. The infection lasts about 48 to 72 hours. Recovery is usually rapid.

Foremost on any parent’s mind is dehydration. A quick means of determining the severity of a child’s dehydration status is by weighing them. It is crucial to weigh the child as soon as possible in order to establish a baseline weight. Fluid loss can be difficult to determine. Weight loss is a good substitute measure. For example, a child who loses two pounds from their pre-illness weight of 20 pounds has lost ten percent of their fluid volume.

Dehydration in children is classified as mild, moderate, or severe depending upon the percent loss of body weight: less than five percent, six to ten percent, and over ten percent, respectively. Moderate to severe dehydration warrants an emergency room visit particularly for infants and toddlers.

For those who were unable to weigh the child prior to their diarrhea, the clinical signs of illness become important. As dehydration worsens, the hands and feet become colder because of poor circulation. The eyes, nose and mouth become dry. There is no pool of saliva under the tongue. Children do not urinate as much and their heart rate increases.

Getting the child to eat solids during the illness is less important than getting them to drink…lots. After two to three days parents can start feeding their children the B.R.A.T. diet (bananas, rice applesauce and toast) and boiled potatoes, noodles, crackers, yogurt, soup, and boiled vegetables.

The series wraps up next week with the common rashes and several vaccine preventive measures.

Related articles:

1. Childhood rashes hard to diagnose at first
2. Why children fight one cold after another
3. Why Children will suffer the most