To the Editor.
—We read with interest the recent article by Dr Gass1 in the Archives. We enjoyed the article and agree with many of the points raised; however, we seriously doubt whether Dr Gass can validly correlate uveal melanoma doubling time and mitotic index in the manner he has attempted to. Data from our studies both on the variability of clinical and ultrasonographic measurements and on growth patterns of small melanomas lead us to dispute a number of assumptions, mathematical formulas, and conclusions that were made regarding growth rate, doubling time, and mitotic index.2,3 Four important assumptions in Dr Gass' study could have introduced significant errors and potentially invalidated the conclusions derived about growth rate, doubling time, and mitotic index.First, we have previously shown that the interobserver and intraobserver variability of clinical measurements of tumor diameter and tumor thickness can be significant.2 These potential measurement
Juster RP, Char DH. Uveal Melanoma: Doubling Time and Mitotic Index. Arch Ophthalmol. 1986;104(2):174. doi:10.1001/archopht.1986.01050140026002