Preoperative factors associated with IOP reduction after cataract surgery.

PURPOSE: To identify preoperative factors associated with postoperative intraocular pressure (IOP) reduction after phacoemulsification cataract extraction in patients with primary open-angle glaucoma (POAG) treated at a Veterans Affairs Medical Center. METHODS: Examination records of 103 eyes of 75 patients with POAG who underwent uncomplicated phacoemulsification cataract extraction were reviewed. Preoperative data collected for analysis included IOP, number of glaucoma medications, spherical equivalent refractive errors, central corneal thickness, anterior chamber depth, and axial length. The IOPs measured 3 to 6 months after surgery were used to calculate the change in IOP after cataract extraction. Statistical analysis was performed to identify preoperative factors associated with postoperative IOP reduction. RESULTS: The mean postoperative IOP reduction was 1.8 ± 3.5 mm Hg (p < 0.001). Seventy-four percent of eyes (76 of 103) had decreased IOP after cataract surgery. Eight percent of eyes (8 of 103) had no change in IOP. Eighteen percent of eyes (19 of 103) had increased IOP after cataract surgery. The mean preoperative IOPs for eyes with increased, same, and decreased postoperative IOPs were 12 ± 2.2 mm Hg, 14.0 ± 2.3 mm Hg, and 16.4 ± 3.1 mm Hg, respectively. The mean postoperative IOPs change for eyes with increased and decreased postoperative IOPs were +2.7 ± 2.1 mm Hg and -3.7 ± 2.5 mm Hg, respectively. Preoperative IOP was the only preoperative factor significantly associated with postoperative IOP reduction (p < 0.001). CONCLUSIONS: Preoperative IOP was the only factor significantly associated with postoperative IOP reduction after cataract surgery in POAG patients. A higher preoperative IOP was strongly associated with a greater postoperative IOP reduction. Patients with low preoperative IOPs tended to have minimal reduction or even a mild increase in postoperative IOPs. These findings have important implications when considering combined cataract extraction and filtration surgery for POAG patients.

Prediction, by retinal location, of the onset of diabetic edema in patients with nonproliferative diabetic retinopathy.

PURPOSE: To formulate a model to predict the location of the onset of diabetic retinal edema (DE) in adults with diabetic retinopathy (DR), at risk for DE. METHODS: In all, 46 eyes from 23 patients with DR were included. Subjects were followed semiannually until DE developed or the study concluded. The presence or absence of DE within the central 45 ° at the final visit was the outcome measure, and data from the prior visit were used as baseline. A logistic regression model was formulated to assess the relationship between DE development and: multifocal electroretinogram (mfERG) implicit time (IT) Z-score, mfERG amplitude (Amp) Z-score, sex, diabetes duration, diabetes type, blood glucose, HbA1c, age, systolic (SBP) and diastolic blood pressure, and grade of retinopathy. A total of 35 retinal zones were constructed from the mfERG elements and each was graded for DE. Data from 52 control subjects were used to calculate the maximum IT and minimum Amp Z-scores for each zone. Receiver operating characteristic curves from a fivefold cross-validation were used to determine the model's predictive properties. RESULTS: Edema developed in 5.2% of all retinal zones and in 35% of the eyes. The mfERG Amp, mfERG IT, SBP, and sex were together predictive of edema onset. Combined, these factors produce a model that has 84% sensitivity and 76% specificity. CONCLUSIONS: Together mfERG, SBP, and sex are good predictors of local edema in patients with DR. The model is a useful tool for assessing risk for edema development and a candidate measure to evaluate novel therapeutics directed at DE.