SCIENTIFIC REPORT

Influence of cataract on optical coherence tomography image quality and retinal thickness

M E J van Velthoven¹, M H van der Linden², M D de Smet¹, D J Faber³ and F D Verbraak¹

¹ Department of Ophthalmology, Academic Medical Centre, Amsterdam, The Netherlands
² OMC Haarlem, Haarlem, The Netherlands
³ Laser Centre, Academic Medical Centre

Correspondence to:
Correspondence to:
M E J van Velthoven
Department of Ophthalmology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; m.e.vanvelthoven{at}amc.uva.nl

Background: As optical coherence tomography (OCT) is widely used for diagnosis and monitoring of ocular pathology, especially in the elderly people, the influence of cataract on image quality and macular retinal thickness was studied.

Methods: In 29 patients scheduled for cataract surgery, preoperative and postoperative OCT scans were obtained. Cataracts were categorised as nuclear, posterior or cortical. Parameters for image quality (signal-to-noise ratio (SNR)) and signal strength and macular thickness were compared. A three-level expert grading scale was used to evaluate the discriminative abilities of SNR and signal strength.

Results: Nuclear cataracts (n = 12) provided better preoperative scans (higher SNR/signal strength) than posterior (n = 7) and cortical (n = 10) cataracts (p<0.004). Postoperatively SNR and signal strength increased significantly in all patients (p<0.001). The SNR was better at discriminating poor from acceptable and good scans than signal strength (area under the receiver operating curve: 0.879 and 0.810, respectively). Postoperative macular thickness overall showed a significant increase (p = 0.005), most evident in patients with posterior cataracts (p = 0.028).

Conclusions: OCT imaging is influenced by cataract; image quality is reduced preoperatively and macular thickness measurements are slightly increased postoperatively. In individual patients, OCT scans remain reliable for gross clinical interpretation, even in the presence of cataract.

Abbreviations: CMO, cystoid macular oedema; LOCS, Lens Opacities Classification System; OCT, optical coherence tomography; SNR, signal-to-noise ratio

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