Role of Optic Nerve Head Characteristics in Predicting Intraocular Pressure Spikes after Cataract Surgery in Highly Myopic Eyes

INTRODUCTION: To evaluate the characteristics of optic nerve head (ONH) in highly myopic eyes and its role in predicting intraocular pressure (IOP) spikes after cataract surgery. METHODS: Patients who are highly myopic and were scheduled for cataract surgery were enrolled in this prospective case series study. IOP was measured preoperatively and at 1 day and 3 days postoperatively. ONH characteristics including area, tilt ratio, lamina cribrosa (LC) thickness, and depth, and the presence of LC defects were evaluated with enhanced depth imaging optical coherence tomography. Factors influencing LC defects and early IOP spike were investigated using multivariate stepwise logistic regression. RESULTS: In total, 200 highly myopic eyes of 200 patients were analyzed: 35.00% had small ONH, 53.00% had ONH tilt, and 14.00% had LC defects. Multivariate analysis demonstrated female patients with larger ONH area and deeper LC tended to have LC defects (all P < 0.05). As to postoperative IOP, IOP change, and incidence of IOP spikes, eyes with small ONH, ONH tilt, and LC defects had similar (all P > 0.05), higher (all P < 0.05), and lower (all P < 0.05) outcomes compared with those without the corresponding characteristic, respectively. Multivariate analysis showed that presence of LC defects and thicker LC were protective factors for early IOP spikes, and axial length > 28 mm was a risk factor (all P < 0.05). CONCLUSION: Female patients with larger ONH area and deeper LC tend to have LC defects, which, together with thicker LC, was correlated with less IOP spikes in highly myopic eyes. TRIAL REGISTRATION: This study was conducted as part of a larger project, the Shanghai High Myopia Study, registered at www.clinicaltrials.gov (accession number NCT03062085).