Macular Degeneration:  A blindness that confounds the scholars and compromises the afflicted

by Cheryl M. Craft, Ph.D.

     Retirement is contemplated as a respite from scheduled labor and an interlude of reflection on life's accomplishments.  Happily that is true for many, but there is a darker side that impairs and compromises the fulfillment of these expectations.  Cardiovascular events and cancer may strike to cut short a life, but polls show that most individuals fear blindness and visual impairment more than death.  Among the most mature of our citizenry lies the almost certain possibility of diminished vision.

     Vision scientists have made unprecedented advances in understanding how the eye works and in devising methods to preserve vision.  Many elderly develop cataracts that obscure a clear vision, but modern surgical techniques allow the removal of the cataractous lens and insertion of an artificial lens in about 20 minutes, normally without complications or pain.  A more serious ocular condition is found in individuals with Type I or Type 2 diabetes, wherein the faulty metabolism of sugar leads to leaky blood vessels that bleed within the light-sensitive retina and cause visual loss.  The bleeding within the eye must be controlled and this is now achieved using laser cauterization. 

     The bane of the elderly comes silently without pain to diminish the most sensitive vision upon which we rely for sharp and colorful images.  The condition is macular degeneration, called age-related macular degeneration when it occurs in later life.  Unlike cataracts or diabetes, the cause of macular degeneration remains a mystery—perhaps the last clinical mountain remaining to be climbed in ophthalmology.  There are many observations that correlate with the final stages of the disorder, but little evidence about what causes the death of cone photoreceptors within the macular, a retinal specialization serving our central visual field.  In some cases, new blood vessels form and then bleed into the eye, causing cone loss if left untreated by laser therapy.  However, laser therapy makes a burn, killing cells, and this is unacceptable within the macula because the treatment would then cause blindness.  A host of possibilities for cause and treatment are being entertained and it remains unclear which will be the first to prove successful.

     The race is on for a cure!  Short-term, we expect that the surgeons and laser therapist will solve the technical problems to provide an expedient treatment of macular degeneration.  We must push beyond the laser to the fundamental cause if we are to provide lasting results.  The seemingly magic mechanisms that control vision and photoreceptor viability are being exposed and this work must move forward for success.  We look to the molecular and cellular biologists to find the faulty, possibly genetic, mechanisms that underlie macular degeneration.  One of the first genetic clues is now known and we are working to answer the questions of how and why!  Then we will have the knowledge to design therapeutics with smart-drugs and possibly genetic therapy to correct the biological error.

     At the beginning of the twenty-first century, it is rewarding to look back on the last century of vision research and clinical ophthalmology, admiring the unexpected and unsurpassed achievements of many scientists.  It is equally comforting to look into the new century as it rises before us in a new millennium.  The summons to vision research and clinical ophthalmology has been delivered already and a cadre of creative scientists in the Mary D. Allen Laboratories for Vision Research is looking forward to the challenge with expectation.  A future in which macular degeneration is controlled and eradicated awaits us and it will provide to the elderly a release from the fear of blindness and the mental disorientation that accompanies visual impairment.