Change of foveal and perifoveal thickness measured by OCT after phacoemulsification and IOL implantation

Purpose Cataract surgery is known to elicit postoperative macular oedema owing to its traumatic effect. The aim of the study was to measure the foveal and perifoveal thickness of the retina after uneventful phacoemulsification and posterior chamber intraocular lens (PC-IOL) implantation. Methods Retinal thickness values of the foveal and perifoveal (fovea+3.0mm, fovea+6.0mm) sectors and the minimum values were measured in a prospective study using optical coherence tomography (OCT) in 71 eyes of 71 patients (34 men, 37 women, mean age: 68.8 years) who underwent cataract surgery. Phacoemulsification and 'in the bag' implantation of a foldable PC-IOL was performed under topical anaesthesia. Data were collected 1 day before the operation, and postoperatively at 1, 7, 30, and 60 days. Contralateral eyes of each patient served as controls. 'Student's t-test' was used for statistical analysis, and P < 0.05 value was considered significant. Results No significant change of the thickness values could be measured 1 day after surgery. However, a significant increase could be detected on the postoperative 7, 30, and 60 days in the perifoveal 3.0 and 6.0mm sectors either calculated alone or averaged together with the foveal values. The initial (preoperative) average value of 234.1 +/- 2.6 mu m (mean +/- SEM, n=536) in the 6.0mm perifoveal region increased to 242.5 +/- 2.6 mu m (mean +/- SEM, n=488, P < 0.01) 1 week, to 247.7 +/- 4.6 mu m (n=352, P < 0.01) 1 month, and to 246.0 +/- 5.9 mu m (n=208, P < 0.05) 2 months after surgery, which proved to be significant. However, the relative change of macular thickness was moderate, 3.5, 5.6, and 5.3% at the above periods, respectively. In a subgroup of patients (n=34) minimum 6 months after cataract surgery, the 6.0mm perifoveal values were found to be elevated at (237.8 +/- 3.9 mu m, mean +/- SEM, n=272) as compared to the control eyes ( 233.9 +/- 3.8 mu m, mean +/- SEM, n=272). The difference was 1.7% and proved not to be significant (P > 0.05). Conclusions Mild subclinical perifoveal oedema following cataract surgery was detected using OCT at postoperative day 7 to 6 months. The minimal and the foveal values in itself are inadequate to describe the phenomenon. The macular thickness values of the perifoveal 3.0 and 6.0mm sectors alone or averaged together with the foveal values provide more accurate description of the postoperative macular oedema. OCT enables the detection of minimal increases in perifoveal retinal thickness even 6 months after cataract surgery.