& lt;span class= & quot;dropcap & quot; & T & lt;/span & hroughout the days of his long, productive life, fur agent and Inland Northwest explorer David Thompson spent time watching the landscape, observing wildlife, aiming a musket to bring down game, sawing and sewing wood in the course of various building projects, peering through a sextant or telescope to determine where he was on the planet, performing neat mathematical calculations on unlined paper, reading and, especially, writing. Since each of these activities involve clear vision, it comes as somewhat of a shock to realize that, from the age of 19 onward, Thompson managed to accomplish all these tasks with only one eye. Could he have been exaggerating when he stated that he lost the sight in his right eye during the winter of 1789-90?
In 1850, the respected Montreal physician Dr. Henry Howard published an account of his treatment of Thompson's vision problems in a volume titled The Anatomy, Physiology and Pathology of the Eye. Howard wrote that the 73-year-old Thompson, by then well known as an astronomer and surveyor for the International Boundary Commission.
[Thompson] was led by his daughter to my surgery on the 24th of February 1843. He stated that he had been blind in his right eye since February 1789 and did not expect I could do anything for it, but that the sight of his left eye had always been good up to the past three months, when it became a little cloudy, which cloudiness gradually increased up to ten days previous to his coming to me on which morning (the 14th of February) he awoke so perfectly blind as not to know it was daylight. He stated that he had applied to two well known medical men who professed to know something of the diseases of the eye and they assured him nothing could be done for him.
Dr. Howard was not so easily discouraged as his medical peers. He examined Thompson's left eye and found a simple capsule-lenticular cataract "full ripe for operation." When he peered into Thompson's blind right eye, he observed a curved scar in the center of the right cornea. The scar was so surrounded by lymph that it rendered the whole cornea opaque, hiding most of the iris. Doctor and patient agreed that they would try to treat both eyes.
For the next three weeks, David Thompson's daughter guided him to Dr. Howard's office for daily visits. After that time, the surveyor had recovered enough of his sight to make the trip on his own. By the time three months had passed, Thompson was able to read and write during daylight hours, although Dr. Howard prohibited him from attempting either activity by candlelight. It was during this period when Thompson told the doctor that:
...on a previous evening he had seen a particular star with his right eye for the first time since he was 19, I then examined his eyes and found scarcely a vestige of cataract remaining in the left eye, and the right cornea so clear that the whole of the iris and pupil were visible, even the cicatrix [that crescent scar] was much smaller, indeed not more than half its original size.
& lt;span class= & quot;dropcap & quot; & T & lt;/span & he treatment that brought about this miraculous cure was the same for both eyes. (Warning: Do Not Try This at Home.) Every day, Dr. Howard began by fumigating his patient's eyes with hydrocyanic acid, a compound often used in those days for fumigating contaminated clothing or food.
Next, Thompson's "eye brows, lids and temples were brushed with a solution veratria." This solution consisted of a grayish-white mixture of poisonous alkaloids derived from pounded sabadilla (also spelled "sapodilla") seeds. These seeds, taken from the fruit of a tropical American evergreen, have long been known as an irritant that makes the eyes water copiously.
According to Dr. Howard, "Sparks of electricity were drawn from round the orbit about three times a week." The use of static electricity generated by various methods has been a staple of medical treatments ever since sparks were discovered.
"Occasionally I dropped on the conjunctiva the two grain solution of atropine." Atropine is a powerful plant medicine derived from various members of the potato or nightshade family (Solanaceae); familiar sources include mandrake and belladonna. Atropine, both organic and synthetic, has a long history as a treatment for wounds, gout, pain, and sleeplessness; in Thompson's day, it was used as an anesthetic before surgery. Moderate doses of atropine have been used since Roman times to dilate the pupils.
In the early stages of the Thompson case, Dr. Howard had employed even more radical methods. "For the first two weeks he took every morning a wine glass full of the infusion of gentian containing a small quantity of the sulphates of magnesia and sulfuric acid." Blue gentian is still valued for its antiseptic qualities. But it seems reasonable to wonder whether the diluted sulfuric acid, delivered directly onto his patient's eyeballs by Howard's version of an eyecup, might not have provided the key factor in burning away the cataract and dissolving some of the scar tissue from the injury that had impeded Thompson's right eye for 53 years.
& lt;span class= & quot;dropcap & quot; & N & lt;/span & o matter how radical these experimental treatments sound today, a century and a half ago they somehow succeeded. After looking over Dr. Howard's methods, Dr. Randall Jacobson of the Spokane Eye Clinic believes he understands why.
"Thompson had a cataract in his left eye and corneal scarring (cause unknown) in his right eye," says Dr. Jacobson. "The account does not describe how the doctor removed his cataract, but certainly he would have been left without a lens (aphakic) subsequent to surgery. While this would not be acceptable nowadays, it certainly resulted in improved vision compared to vision with a severe cataract.
"As far as his Thompson's right eye goes, the most common cause of corneal scarring is infection or trauma," Jacobson continues. "The medicines/chemicals applied to that eye most likely 'burned' the scar away, allowing for temporary improved vision. I would think this would have been a painful treatment. The atropine would dilate his eye and might allow for him to 'see around' the scar as well. A current approach to corneal scarring is a corneal transplant for severe scarring, or a laser (which also essentially burns away scarred tissue in a precise manner) for less severe scarring. According to the account, his improved vision was only temporary, as I would suspect the treatment would have resulted in the scar reforming with time."
Dr. Howard's miracle cure might have been only temporary, but it wasn't until 1850 that the light of Thompson's eyesight faded so completely that he could no longer put pen to paper. Thanks to Dr. Howard's work, and perhaps a generous helping of good luck, David Thompson was able to unfold dozens more eccentric and entertaining stories in his Travels manuscript, many of which enrich all that we know about his journeying through the Inland Northwest.
So here's to sapodilla seeds and electric sparks, blue gentian and belladonna, plus a wee wineglass of sulfuric acid in the morning: With their help, David Thompson gained seven more years of vision.
Thanks to Dr. Randall Jacobson and Karen Franks for their help and insight.