This article introduces a wireless power and data transfer (WPDT) system designed for low modulation index (MI) scenarios, specifically targeting smart contact lenses (SCLs). Conventional WPDT systems using load-shift keying (LSK) for implantable medical devices rely on proximity to ensure sufficient MI for wireless data transfer (WDT). However, SCL applications face a bottleneck in WDT due to a small-sized antenna and increased distance between the SCL and external reader (RX) unit, resulting in low MI. The proposed WPDT system overcomes this limitation by implementing an integrating receiver that employs a tradeoff in data rate to improve signal-to-noise ratio (SNR) under low MI conditions, thus supporting robust data communication at extended ranges. The proposed system utilizes two co-optimized chips—an RX and a transponder (TX)—in a full chain of a 433-MHz WPDT system. With an MI of 0.1%, the system achieves a bit error rate (BER) of less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 10^{-6}$</tex-math> </inline-formula>, demonstrating an improvement of more than 250 times compared to the best previously reported results. The designed ICs are fabricated using 0.18-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>m CMOS technology. The SCL prototype incorporates a loop antenna, a resistive intraocular pressure (IOP) sensor, and the TX chip. The full system is validated both in vitro with 3-D-printed eye models and in vivo with a live rabbit. This work facilitates WPDT in compact biomedical devices such as SCL, addressing the inherent challenges of range limitations in low MI environments.