2016 - 2 Issue

Original article

The Effect of Cataract Surgery on the Reproducibility and Outcome of Optical Coherence Tomography Measurements of Macular and Retinal Nerve Fibre Layer Thickness

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Introduction: Optical coherence tomography (OCT) is a non-invasive imaging technique used for the examination of the macula and peripapillary retinal nerve fibre layer (RNFL), the result of which may be affected by the quality of the scanned image. The aim of our study was to assess the influence of uncomplicated cataract extraction on the measurement of macular and RNFL thickness with OCT and to determine the reproducibility of this method before and after cataract surgery in a group of healthy people. We also evaluated the effect of different intraocular lenses (IOL) (with/without yellow filter) on the reproducibility of the OCT examination.

Methods: The study group included 51 eyes of 51 patients who underwent cataract surgery with posterior chamber IOL implantation. Macular and RNFL thickness were measured with spectral domain OCT (Optovue, Model RT 100) one week before surgery, and postoperatively after one and six months. Three OCT scans were performed at each visit to assess the reproducibility of the measurement. Data were statistically processed.

Results: Analysis of the changes in macular and RNFL thickness showed a significant increase in retinal thickness, with the maximum increase one month after surgery, and regression of this thickening six months after surgery. Reproducibility of OCT examination improved significantly after cataract surgery, even though the preoperative values were of low coefficient of variance and therefore of high accuracy. No difference was found in the use of different intraocular lenses on the reproducibility of the OCT examination.

Conclusion: The presence of cataract affects the OCT measurement of macular and RNFL thickness. The reproducibility of the method significantly improves after cataract surgery. It is likely that the increase in macular and RNFL thickness after cataract removal is partly due to improvement in the quality of the scanned image and thus to the greater accuracy of the OCT examination.