Verification of a formula developed to predict the postoperative intraocular pressure after cataract surgery in primary angle-closure glaucoma.
BACKGROUND
The aim of this study was to verify the accuracy of a formula predicting postoperative intraocular pressure (IOP) after phacoemulsification and intraocular lens implantation (PHCE-IOL) in primary angle-closure glaucoma (PACG). In a retrospective chart review of patients with PACG who underwent PHCE-IOL between 2011 and 2014, we collected preoperative IOP, axial length, anterior chamber depth (ACD), number of pre-PHCE glaucoma medications, and IOP and glaucoma medications at 1 month and 3 months post-PHCE.


METHODS
Post-PHCE IOP values at 1 month and 3 months were compared with those predicted using the formula: postoperative IOP = 6.354 + 0.186 pre-PHCE IOP × pre-PHCE ACD. Agreements between measured and predicted IOP values were analyzed using correlation coefficients and Bland-Altman plots.


RESULTS
Of the 62 eyes included, the average pre-PHCE IOP was 19.47 ± 5.84 mm Hg. Post-PHCE IOP values were 14.94 ± 4.03 mm Hg at 1 month and 14.21 ± 3.51 mm Hg at 3 months. Patients using more preoperative medications tended to show greater postoperative declines in medication usage. Predicted IOP significantly correlated with post-PHCE IOP measured at 1 month (R = 0.314, p = 0.013) and 3 months (R = 0.325, p = 0.01). Bland-Altman plots of difference against average of measured and estimated IOP revealed two cases falling outside±1.96 standard deviation at 1 month, and five cases at 3 months, indicating good consistency between measurement and prediction.


CONCLUSIONS
This formula was useful for predicting IOP at 1 month and 3 months after PHCE-IOL in PACG. It aids clinicians in preoperative assessment of whether PHCE-IOL alone is likely to achieve acceptable postoperative IOP control.
Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
Yu-Fan
YF
Chang
Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
Yu-Chieh
YC
Ko
Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.
Ling-Ing
LI
Lau
Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC. Electronic address: jlliu@vghtpe.gov.tw.
Catherine Jui-Ling
CJ
Liu
D000368:Aged; D002387:Cataract Extraction; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007429:Intraocular Pressure; D019654:Lens Implantation, Intraocular; D008297:Male; D018918:Phacoemulsification; D011184:Postoperative Period; D012189:Retrospective Studies
anterior chamber depth; intraocular pressure; phacoemulsification; primary angle-closure glaucoma