Dr. Cheung’s Blog 2/5/2015

Dr. Cheung’s Blog 2/5/2015

February 2, 2015

Cats have nine lives

Have you ever wonder why human have round pupils and cats have oval ones?

We got a new cat.  His name is Smudge, aka Prince.  Technically, he is my almost-thirteen-year-old daughter’s cat.  It was her idea; something new for the New Year and I thought it would be a good way for her to develop more responsibility.  I have a feeling, however, that I will be doing the lion share of the litter box clean up.

Smudge is a really sweet cat.  He is gentle with our eighteen-month-old twins, even when he was poked by their little fingers.   He also gets along fine with my wife’s cat Shiva who made it quite clear that she will remain the first cat.  Shiva hisses at Smudge often and he basically just learned to mind his own business.  Good survival strategy for a male in a household.

Smudge’s favorite spot during the day is the twins’ changing table by the window.  He loves to lounge there to bathe in the light.  His shiny beautiful coat is all black except for a few reddish brown spots, hence the name Smudge.    Smudge has a distinctive hoarse low-pitched cry.  At night, he meows and yowls incessantly to be let out only to return punctually at 6:20 each morning.  His eyes are green and expressive with vertically oval pupils.  Have you ever wonder why human have round pupils and cats have oval ones?  The conventional thinking is that a slit-like or vertically oval pupils can dilate faster – an adaptation to cats’ nocturnal activities.  This explanation never sits well with me since normal human pupils can react to light or darkness pretty darn fast too.  Another explanation that makes more sense to me is that a vertical pupil provides a better focus on the horizontal plane which can be very helpful to carnivorous animals such as cats.  In contrast, herbivorous animals tend to have horizontally oval pupils because when they lowered then heads to graze, the pupils will then be oriented vertically to allow them better focus on the horizontal plane for approaching predators.

Yet, more recent studies suggest that the slit pupils in cats had evolved to compensate for their large lenses in which the peripheral parts of the lens have a different focal length than the center.  This multifocal lens can cause color aberration but the slit pupil help to reduce the color distortion and allows cats to have all colors in sharp focus in one plane on the retina.

A misstep in the development of the human eye can result in a cat-like oval pupil too.  In the developing embryo, the primitive eye first appears as a thick pancake at 25 days of gestation.  The pancake then starts to fold into an upside down taco and the gap is called the embryonic fissure.  The fissure is there to allow blood vessels to grow into the developing eye.  Beginning around the second month of gestation, the two lips of the fissure meet and fuse, first in the mid-region of the eye and then zippers forward and backward to complete the globe.  Incomplete closure results in a coloboma and the extent of the defect and its visual consequences vary depending on the degree of the zipper malfunction.  An isolated small coloboma in the front part of the eye may produce a cat’s eye like this picture.  The affected patient may have a little bit more glare and photosensitivity but still enjoys 20/20 vision.  In contrast, a large coloboma in the back part of the eye involving the retina and the optic nerve like this second picture can have a devastating effect on vision.   Retinal detachment may develop from the edge of a retinal coloboma, further compromising the patient’s vision.

Coloboma can affect one of both eyes and can be inherited.  A child with a severe coloboma may have a parent with a very subtle coloboma that was never recognized before.  Coloboma may be accompanied by multiple systemic abnormalities in a patient in what is known as the CHARGE association.  This includes: Heart defect, choanal Atresia, mental Retardation, Genitourinary abnormalities and Ear abnormalities.  Therefore, a good physical exam by the pediatricians (and appropriate testing if indicated) is required when a young child is identified with an ocular coloboma.

Back to Smudge.  I worry about him out there in the night when he is exposed to cold, wind and potentially dangerous wild life such as raccoons who pay homage to our home frequently.  Somehow, he likes it out there and he comes back unscathed every morning.  They say that cats have nine lives.  I wonder why the number nine.  Nine is a lucky number in Chinese culture.  So I guess cats are just inherently lucky.  Another legend has it that the ancient Egyptian Sun God, Atum-Ra, took the form of a cat when he visited the underworld.  Atum-Ra also gave birth to eight other gods; so he was nine lives packed into one.    Ancient Egyptians also believed that cats have divine properties and perhaps that’s where the nine lives legend began.

There is no doubt in my mind that cats have only one life but their ability to dodge death is phenomenal.  Watch a cat fall from high places, it almost always land on its feet.  Their smallness, agility, and keen sense of balance allow them to constantly reposition themselves in difficult or even life-threatening situations.  If I have to choose an animal to represent my practice, it would be a cat.  I have been in practice in Kitsap County since 1998.  I was in two group practices before opening my own office in Silverdale in 2002.  We added the Bainbridge office in 2007 and moved our Silverdale office in 2012.  I am happy to announce that we are in the process of expanding our Silverdale location and we will be consolidating our two offices into one in April.  This was done mostly in response to the changing technological needs in the practice of ophthalmology and we are acquiring several pieces of new equipment so we can continue to deliver efficient and state-of-the art eye care to our patients.  These new technologies are expensive and we cannot afford them in both of our existing offices.  We also did not feel right to deliver different level of care between the two locations, hence the need to consolidate.

The practice of medicine is evolving rapidly, at a pace faster than anything I have ever witnessed since I have been a doctor.  The direction of the change, I am afraid, is not all positive.  Small physician offices, which formed the cornerstone of the delivery of health care in this country for decades, are being bought out by hospitals.  Governmental regulatory efforts and technological burden are the main factors that drive this change.  Unfortunately, health care administered by a mammoth institution tends to lack the personal touch.  Patients become customers or numbers.  Physicians are monitored by administrators who track how many minutes they spend with their patients in the name of efficiency.  Doctors stop looking into their patients eyes and turn their gazes to the computer screens in order to enter data required by the government.  I, along with many other physicians, am saddened by this process.  It really takes the fun out of our profession.  To me, the art of medicine is about building positive relationships.  While science and technology cure diseases, how a patient feels healed and how he or she feels cared for is through positive relationships and experiences with the doctors, nurses and the front desk staff.  This I feel is the biggest disconnection in today’s medicine.   While a tiger is big and strong, it won’t curl up cozily next to you on a sofa like Smudge.  Unless you are a circus animal tamer, it is pretty hard to form a relationship with a tiger.  To keep the personal touch in my office, I hope to stay small like a cat while striving for technological excellence.    I also hope that our small practice can remain nimble like a cat so that we can land on our feet when we pull through this turbulent time.

That 80-90% of overall UV damage to our eyes is accumulated before the age of 18! Like skin damage from UV exposure, we now know occurred for the most part from exposure before the age of 18. Kids in UV protected sun glasses is highly recommended. Protect their eyes just like you do their delicate skin!

Water & contacts don’t mix. To help prevent eye infections, contact lenses should be removed before going swimming or in a hot tub. Alternatively, wear goggles.

The lenses in children’s eyes do not block as much UV radiation as they do in adults’ eyes, putting them at increased risk for sun damage to the eyes.

Left untreated, glaucoma can lead to vision loss. Glaucoma can strike without pain or other symptoms and is a leading cause of blindness in the United States. According to the American Optometric Association (AOA), early detection and treatment is critical to maintain healthy vision and protect the eyes from the effects of potentially blinding diseases, such as glaucoma.

Age-related macular degeneration is a leading cause of blindness. Learn the risk factors for this disease? Having a close family relative with age-related macular degeneration (AMD) puts you at higher risk for developing the disease yourself.