Dr. Cheung’s Blog 10/25/2014

Dr. Cheung’s Blog 10/25/2014

October 25, 2014

Do Not Go Gently Into That Good Night

My wife and I just ran the Victoria half marathon this morning.  The weather was perfect for running with a mild chill in the crisp autumn air under a slightly over-casted sky.  The course was mercifully flat and pleasing to the eyes too.  We began in downtown Victoria where the glorious British Columbia Parliament Building was still glowing in the pre-dawn light.  We then wound through a beautiful public park, a quaint British-accented neighborhood and finally hugged along the shore as we approached the finish line.  Local residents and musicians came out in droves to cheer us on.  The positive energy was palpable and I was reasonably happy with my result.  I ran this course four years ago and had my personal best here.  This time around, I am seven minutes slower than my last.  Granted, I did not train as rigorously as my last because of the twins but I cannot help to wonder if aging is finally catching up to me.  As an ophthalmologist, I am not immune from the aging effect on my own eyes.   Now that I have passed my mid-forties, bifocal glasses have become a necessity of daily life.  This natural decline in our ability to focus up close is called presbyopia.

Accomodation is the process by which the lens in our eyes becomes more round and increases its focusing power to bring light from near objects onto our retina.  In humans, the lens is held within a capsular bag which in turn is suspended within a circular muscle (ciliary muscle) by tiny fibers called zonules.  One theory of accomodation proposes that when the ciliary muscle contracts, the tension on the zonules is relaxed and the elastic lens becomes more curved and powerful.  Presbyopia is the normal progressive loss of accomodation due to the loss of the elasticity of the lens.  In other words, the aging lens is less pliable to the contractive forces of the ciliary muscle.  The ciliary muscle appears to get weaker too with age with more connective tissue and less muscular fibers on microscopic studies.  However, stiffening of the lens is the most important causative factor to presbyopia.

Like many middle age folks, I dislike wearing bifocal glasses.  My vision is excellent with them but I hate having something over my face all the time.  I love contact lens for distance but my near vision suffers due to presbyopia with the regular monofocal contact lens.  I experimented with monovision, in which my dominant right eye was corrected for distance and my left eye was corrected for near vision.  This approach caused me and many others a slight headache which improved with time.  However, I lost some depth perception with this method and for my work, this was not a viable option.  Recently, I have great success with multifocal contact lens, thanks to the encouragement of my associate, Dr. Dixita Patel, the contact lens specialist in our practice.

There are two classes of contact lens that help to ameliorate presbyopia.  The first class (alternating vision) is similar in design and function to regular bifocal spectacles in which there is one segment for distance and one segment for near.  The retina receives light from one image location at a time: distance or near.  The other class that I personally preferred is called simultaneous vision bifocal contact lens which sends light to the retina from both distance and near at the same time.  The design of this class of contact lens may utilize diffractive technology in which concentric grooves on the back surface of the lens split light rays into two focal groups: near and far.  I found that contrast is diminished with this kind of contact lens because distance targets are washed out by light coming from the near and vice versa.  However, this is very tolerable and I have come to love them and wear them now on a daily basis.

This same diffractive technology is also used in the design of multifocal intraocular implants for patients undergoing cataract surgery.  I have been very impressed by the AcrySofReStor multifocal lens implant, manufactured by Alcon. The central 3.6 mm of this lens contains diffractive grating and provides excellent near and distance vision.  The peripheral part of the lens is distant-dominant and most important in low-light conditions.  In one study, 78% of patients who received this lens implant in both eyes never needed glasses six months after surgery and 20% of the study patients required glasses sometimes.  Intermediate vision is also very good with the newer +3.00 add version of the ReStor Lens but halos, glare and decrease in contrast, particularly in low light conditions, may be problematic for some patients.  Not all patients with cataracts are good candidate for this exciting lens technology and I would be happy to discuss your individual needs if you are interested in this lens for your cataract surgery.

Modern medicine has provided us with some amazing technologies to counter the physiologic effects of aging.  They don’t stop us from realizing that we are getting old though.  The best antidote to that, I think, is to live a life that is purposeful and keep doing what we love and enjoy.  When I did my first full marathon in Vancouver in 2006, I crossed the finish line with a runner that was in his eighties.  It was his 107th marathon and he sure made an indelible impression on me.  Aging is just a little speed bump for us to hop over along the path of life.  I plan to keep on running even though I am a bit slower now and my right knee hurts on occasion.   I also plan to keep on operating even though I have to constantly adjust the focusing foot pedal of the microscope now as the accomodative amplitude in my own eyes weans.

I am reminded of the first few lines of a poem by Dylan Thomas:

Do not go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.

This month, I celebrated the lives of two amazing local physician: Doctor Robert Bright, a family physician and Doctor Terry Olsen, an ophthalmologist.  They were models of caring and commitment which we, the “young” physicians should strive to emulate.  They did not go gently into that good night.  They both enjoyed long and successful practice and they never stopped caring for their patients.  May they rest in peace now.