Customized sclerotomy improves macular access in Chinese eyes with axial length ≥ 28 mm

This study aimed to explore the relationship between axial length and ciliary body length, along with the potential anatomical variability among different races. Based on this, a new positioning for sclera incision in pars plana vitrectomy for patients with axial length ≥ 28 mm was proposed and evaluated for feasibility and safety.

83 Chinese patients were enrolled. Pre-operative subjective refraction and axial length were obtained. The ciliary body length was measured intraoperatively. Data of Caucasian population from a published paper are also reviewed and analyzed. From all the enrolled Chinese patients, we selected 7 patients with axial length ≥ 28 mm and who needed vitrectomy for macular diseases. New technique was used to make scleral incisions, and they were followed up for at least 12 months.

The temporal and nasal ciliary body length have significantly positive correlations with axial length (p < 0.001, r = 0.386; p = 0.001, r = 0.357). The range of temporal ciliary body length and nasal ciliary body length in Chinese with axial length ≥ 28 mm are 5.5-10.5 mm and 5.5-9.5 mm. The mean, range, variance and standard deviations of ciliary body length in Chinese are greater than Caucasian with axial length ≥ 28 mm (p = 0.00034; p = 0.04996). No surgical-related complications occurred in the 7 patients with adjusted incision sites.

There is a significant positive correlation between axial length and ciliary body length in nasal and temporal quadrant. Compared to Caucasians, Chinese population with axial length ≥ 28 mm exhibit higher variability in the nasal and temporal ciliary body length. Therefore, positioning the scleral incision 2-3 mm anterior to the ora serrata facilitates safer access of surgical instruments to the macular. This novel technique is not only simple but also offers improved cost-effectiveness.

This study has been registered on the Chinese Clinical Trial Registry website, registration number: ChiCTR1800015732 (registration date: 17th April, 2018).