ABSTRACT
Mucopolysaccharidoses (MPS) is a group of lysosomal storage disorders that lead to accumulation of glycosaminoglycans (GAGs) in many tissues and organs, resulting in different clinical features. In this study, we conducted the manifestation changes of refractive error, corneal clouding, and intraocular pressure in two Taiwanese MPS VI patients with enzyme replacement therapy (ERT) initiated at the age of eight. In case 1, hyperopia was noted before and after ERT. Clinical observation showed no significant improvement in corneal clouding after ERT. In case 2, hyperopia was also noted initially before ERT and unable to be measured due to severe corneal opacity. Clinical observation showed no significant improvement in corneal clouding in after ERT, and the best-corrected visual acuity worsen and keratoplasty was needed in both eyes. Case 2 also had ocular hypertension and suspect MPS VI-related. However, due to severe corneal clouding, optic disc changes were hard to examine, and visual field was unable to be tested. Although some literature shows that ERT may be effective in preventing and/or clearing corneal stromal GAGs, accumulation and the timing of treatment initiation cloud be a clinical prognosis predictor; in this experience, no significant improvement of corneal clouding was observed in patients with MPS IV after ERT. Hyperopia and glaucoma were noted, and showed no changes after ERT. Severe corneal clouding can lead to difficulties in diagnosis and monitoring of hyperopia and glaucoma.
ABSTRACT
BACKGROUND: Many articles in the surgical literature were faulted for committing type 2 error, or concluding no difference when the study was "underpowered". However, it is unknown if the current power standard of 0.8 is reasonable in surgical science. METHODS: PubMed was searched for abstracts published in Surgery, JAMA Surgery, and Annals of Surgery and from January 1, 2012 to December 31, 2016, with Medical Subject Heading terms of randomized controlled trial (RCT) or observational study (OBS) and limited to humans were included (n = 403). Articles were excluded if all reported findings were statistically significant (n = 193), or if presented data were insufficient to calculate power (n = 141). RESULTS: A total of 69 manuscripts (59 RCTs and 10 OBSs) were assessed. Overall, the median power was 0.16 (interquartile range [IQR] 0.08-0.32). The median power was 0.16 for RCTs (IQR 0.08-0.32) and 0.14 for OBSs (IQR 0.09-0.22). Only 4 studies (5.8%) reached or exceeded the current 0.8 standard. Two-thirds of our study sample had an a priori power calculation (n = 41). CONCLUSIONS: High-impact surgical science was routinely unable to reach the arbitrary power standard of 0.8. The academic surgical community should reconsider the power threshold as it applies to surgical investigations. We contend that the blueprint for the redesign should include benchmarking the power of articles on a gradient scale, instead of aiming for an unreasonable threshold.