Re: "The effect of orbital decompression surgery on lid retraction in thyroid eye disease".

To the Editor: It was with great anticipation that we read “The Effect of Orbital Decompression Surgery on Lid Retraction in Thyroid Eye Disease” by Cho et al. We have been awaiting a study to either confirm or contradict our findings as published in our article entitled “Normalization of Upper Eyelid Height and Contour After Bony Decompression in Thyroid-Related Ophthalmopathy: A Digital Image Analysis” Arch Ophthalmol 2004;122(12):1882–1885. Perhaps, the authors were unaware of our publication or the aticle by van den Bosch WA et al., as neither were cited in the article despite their assertion, “To our knowledge, there no other studies that examine the effect of orbital decompression on eyelid position”. There are a number of critical points that we must respectfully illustrate to the authors. The methodology used by the authors is simply primitive. There is no mention of whether the measurements were performed by photographic analysis or by a ruler held up the patients face. If the analysis was done by photographic analysis there is no mention of the photographic technique. Small changes in head tilt and fixation point can greatly alter results in eyelid position, palpebral fissure width, and exposed area. Calculations based on retrospective review without clearly defined methodology to take consistent photographs and measure them in a reliable and reproducible fashion should be inadmissible in the modern digital age. Although we recognize that there can be a great deal of variability in the eyelid position and that a single photograph may not be representative, there should be some attempt in the methodology to minimize as many influencing factors as possible. There have been numerous publications dating back well over a decade in the literature on digital photographic analysis and its accuracy. This type of analysis should be considered the gold standard for any type of eyelid image analysis. Any type of measurement not using well defined, fixed photography, and computer generated analysis should be considered no better than order of magnitude estimates. For selection criteria, it must be noted that the authors included patients in their data set using extremely lax exclusion criteria. Patients included in the study underwent different types of decompression surgery, had subsequent strabismus surgery, eyelid surgery, and radiotherapy. All of these variables should be minimized in order to produce consistent, relevant results. If the précis of the article is that decompression surgery can potentially affect eyelid position then all other factors that could potentially alter eyelid position other than decompression surgery should be neutralized. This would include strabismus surgery, eyelid surgery, eyelid crease, or lateral canthal incisions that could alter eyelid position, radiation, and any other factors that could affect the outcome of the study. None of these variables appear to have been accounted for in their methodology further contributing to the inconsistency and unreliability of the data obtained in this study. Finally, eyelid height or eyelid retraction alone does not completely define the effect of upperor lower-eyelid position. We found a direct correlation between the amounts of decrease in axial proptosis to the amount of nasal migration of the uppereyelid peak (i.e., reduction in “lateral flare”). Decrease in axial proptosis via decompression surgery also correlates to a reduction in the average exposed surface area of the palpebral fissure. Both of these notable findings are reproducible and logical and are not addressed in Cho et al. To summarize, we believe that reductions in axial proptosis from orbital decompression surgery has many significant effects on eyelid position and contour that extend beyond the simplistic measurement of marginal reflex distance. These changes can be easily quantified and measured using digital imaging analysis. Although we welcome the contributions of the authors, we feel strongly that digital imaging analysis capable of quantifying height and contour changes of the eyelids should be the standard by which eyelid position is assessed and reported. Furthermore, all photographs taken for the purpose of analysis must be standardized in order to produce sophisticated, reproducible results. Finally, based upon our careful review of the Cho et al. study, we were unable to endorse the generation of meaningful data without proper elimination or minimization of confounding factors and other potentially relevant variables. For all these concerns, we do not find the conclusions of the authors to be valid or relevant.