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BACKGROUND To investigate a conclusive relationship between diabetic retinopathy (DR) and the risk of stroke, we performed a meta-analysis of the available relevant studies. METHODS After a systematic search of studies in electronic databases, we screened all studies reporting the risk of DR status and stroke incidence and calculated their odds ratios (ORs) and hazard ratios (HRs). The effects of type of diabetes and severity of DR were also considered for subgroup analysis. RESULTS We included a total of 19 studies involving 45,495 patients. A pooled HR=1.62 (1.28, 2.06) were found for the risk of DR and stroke in diabetic patients. In a subgroup analysis performed on the type of diabetes, the results showed a significant association between stroke incidence and DR status in patients with T2D (OR: 1.78; 95% CL: 1.53, 2.08), but this association was not conclusive in T1D (OR: 1.77; 95% CL: 0.48, 6.61). The results of the subgroup analysis with diabetes severity showed that both mild and moderate NPDR status and severe NPDR and worse status significantly increased the risk of stroke with HRs of 2,01 (1.45, 2.78) and 2.27 (1.52, 3.39), respectively. CONCLUSION DR status in diabetic patients is associated with an increased risk of stroke. This correlation was robust in patients with T2D, but uncertain in T1D. Based on this result, we have perhaps found the new factor for stroke management, so we analyzed the necessity and advantages of considering DR as a factor for stroke screening and risk management in our studies.

Quasi‐phase matching (QPM) is a technique in nonlinear optics for achieving efficient energy exchange among optical waves at different frequencies, by spatially modulating the quadratic nonlinearity (χ (2)) of the medium. To realize the full potential of QPM, 3D spatial modulation of χ (2) is required. This has become experimentally feasible recently thanks to the invention of femtosecond laser‐based nonlinearity engineering in ferroelectric crystals. Herein, the first experimental demonstration of QPM second harmonic generation (SHG) in a nonlinear cubic crystal system is presented, in which χ (2) modulations form simple cubic, body‐centered cubic, face‐centered cubic, and diamond cubic lattices, respectively. The experimental results indicate that these nonlinear cubic structures share the same primary reciprocal lattice vectors (RLVs), but possess different Fourier coefficients (in conventional cells), leading to SHG with similar angular resonances but various intensity distributions in the far field. This work contributes to a comprehensive understanding of nonlinear optical processes in 3D periodic media, and thus sheds light on the development of high‐performance QPM devices.

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