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Herbert Hoover (Corning/ANSI/ISO)
AO's Hague UV Fluorescing Lamp -
Herbert Hoover email : (June 19, 2009)
The picture of AO's "Hague Fluorescing Lamp" did stir some thoughts. First, my obligatory nit-pick: the lamp doesn't fluoresce, the dye does. However, I don't have a neat, concise, name for it that would do the job. I forgive their advertising agency.
The lamp resembles a couple of high intensity UV lamp systems that were listed in chemical and laboratory supply catalogs, at least into the 1990s. In 1959, the lens of the Hague Lamp was certainly made by Corning Glass Works (the Japanese had not yet taken over such business).
The lamps (bulbs) probably were made by Sylvania. The lens was a heavily cobalt-doped glass. The AO claim is, effectively, that the UVB is blocked. I looked at the cobalt color filters in Corning's old catalog. It is evident that an auxiliary filter would have been needed. It should also be stated that the cobalt glass lens is ultraviolet transmitting, visible absorbing, so that the relatively weak fluorescence is not obscured by visible light from the lamp.
Judging by the appearance of the transformer for the Hague lamp, it was of much lower power than those of the cataloged systems. Thanks be for that.
My first eight years at Corning Glass Works were in product development, where I learned that my strength was measurement and analysis, not invention.
In April, 1961, I moved to a technical services department, where I did spectrophotometry, radiometry, refractometry, and other optical chores. During my first two years in this department, I shared an office with a man who had been a consultant to Corning's Color Filter Business for almost thirty years. I learned much about color filters from him.
When he was transferred to another department, I became the consultant to the Filter Department, on applications, not on glass chemistry. A call from an ophthalmologist in Pittsburgh was given over to me. He was seeking a filter that could be used with fluorescence microscopy, I think under the operating microscope. I selected a Corning cobalt filter, calculated to an appropriate thickness, and told him how to order filters, cut to size, from the filter sales department. A short time later, I learned that he was marketing, in ophthalmological journals, the ". . . cobalt filter for fluorescence microscopy"; (the ellipsis represents his name, which I have forgotten). I cite this as evidence for my competence to recognize cobalt glass lenses on UV lamps.
In 1962, I got associated with photochromic glass, which I have continued to the present, about 47 years. In 1984, I made my first intrusion into the complacency (except for the stirrings by Tom Loomis) of the Z80 Sunglass subcommittee. I presented my analysis of solar UVB irradiation at the cornea and its implication for needed blocking by sunglasses. It took 12 years to get the ANSI Z80.3 standard updated (from 1979) with rational (vis a vis "I'm the expert, so do it my way") foundations for the UV transmittance requirements.
In 1986, Tom and I were invited to present our analysis at a meeting of AOA, in Chicago. Dr. Pitts's paper was a short slide show of his flower-raising hobby (very impressive) and a small amount of discussion of his paper.
Dr. Waxler, too, spoke. He opened by showing a cartoon that I had concocted for him: A store-front with pairs of sunglasses displayed on manikin's heads, one with a Smiley-Face hangtag, the other with a Death's-Head hangtag. Above the window was the sign, "Morris's Mercantile Emporium". From there, he informed that, just completed at the Northwestern University School of Medicine, was a study on the additive effect of UV irradiation of the retina. Don't go away just yet; this is the lead into the connection with the Hague Lamp.
In 1988, I received a telephone call at home, from Morris. He asked my thought on a new spectrophotometer to be acquired by Robert James's test lab at CDRH. I assured that the choice was satisfactory. It was an appropriate balance of cost and performance. I then asked about the Northwestern study. He said that the leading investigator, a Dr. Li, a visiting scholar from China, had taken the photographs of the exposed retinae with himself, to China, for analysis. The US members had lost track of Dr. Li, but he was being tracked down.
The paper on the Northwestern research was published in the December, 1990, issue of the journal, Retina. The roles of the FDA were to provide a significant part of the funding, provide the Rhesus primates, provide the radiometrist from James's laboratory, and provide instigation and final editorial work by Dr. Waxler. Dr. Eifrig, at the Spring meeting of ANSI Z80, expressed his approbation of the paper and its results, until I told him that the radiometrist had made a rather large error, having underestimated the irradiances of the retinae by a factor of between ten and eighty, with my best estimate being a factor of thirty.
The UV source for this research was one of the high intensity lamp systems that used a Sylvania lamp. One of these lamps was designated, "spot", the other, flood". In keeping with what I think I is a characteristic of medical and epidemiologic literature, the information provided is rarely adequate for a qualified reader to evaluate the reliability of the conclusions. In the present case, the lamp was described as having been purchased from the Thomas supply company in New Jersey. Because I was not entirely ignorant of the supplier and the probable nature of the lamps, I tracked them down, recognized which of the two types must have been used, and then analyzed the radiometry. Unfortunately, Dr. Waxler's assertions at Z80 kept me too busy to write a critique of the Retina paper.
Some years later, I borrowed a "Spot" lamp and made measurements of its relative irradiance over the focal plane, to understand more fully what had been happening in the Northwestern study. Again (but not because at Dr. Waxler) I couldn't find time to write up my analysis, but, stated simply, the radiation field from this lamp is such that it could not yield a reliable estimate of localized irradiance on the retina.
PDF of above 1959 AO product info
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