Conclusions: Increasing lens thickness was the anterior segment parameter most associated with IOP spikes in glaucoma patients after cataract surgery.

Objective: To determine whether anterior segment anatomy is associated with intraocular pressure spike on postoperative day 1(POD1) after cataract surgery in participants with glaucoma.

Methods: Optical biometry measured multiple eye parameters before cataract surgery in 48 eyes(39 participants) with glaucoma. Preoperative intraocular pressure(IOP) was the mean of 3 visits prior to cataract surgery and postoperative IOP on day 1 was defined as the IOP on POD1 after cataract surgery. Change in IOP was the difference between postoperative and preoperative IOP. A "5 mmHg IOP spike" and "10 mmHg IOP spike" were defined as POD1 IOP ≥ 21 mmHg with IOP ≥5 or ≥10 mmHg higher than preoperative IOP, respectively.

Results: Mean POD1 IOP(22.8±8.8 mmHg) was significantly higher than mean preoperative IOP(15.3±3.6 mmHg, P <0.001). A 5 mmHg IOP spike occurred in 45.8% of eyes(22/48 eyes), and 29.2% of eyes(14/48 eyes) had a 10 mmHg IOP spike. Multivariable analysis showed that increased lens thickness(LT) and axial length(AL) were associated with a 5 mmHg IOP spike ( P =.04 and P =.09, respectively), and increased LT was associated with a 10 mmHg IOP spike ( P =.02). When using change in IOP, increased LT and lower number of preoperative medications were significant predictors of increased IOP after cataract surgery.

Conclusions: IOP spikes were common in glaucoma patients after cataract surgery and were associated with anterior segment anatomy. Future studies may use risk factors to identify and prevent IOP spikes in glaucoma patients after cataract surgery.