Endoscopic techniques are broadly used in medicine. Small diameter endoscopes are either made as fiber bundles or, beneficially, as graded index lenses. Fiber bundles can withstand a mechanical load during their use but the GRIN lens's performance can be affected by its deflection. Here, we analyze the effect of deflection on the image quality and unwanted associated effects with relation to the eye endoscope we designed and built. We also present the result of our effort to make a reliable model of a bent GRIN lens in the OpticStudio software.