Influence of Cataract on Optical Coherence Tomography Image Quality and Retinal Thickness

¹ Academic Medical Centre, Dpt of Ophthalmology, Netherlands
² OMC Haarlem, Netherlands
³ Academic Medical Centre, Laser Centre, Netherlands

^* To whom correspondence should be addressed. E-mail: m.e.vanvelthoven{at}amc.uva.nl.

Accepted 3 July 2006

	Abstract

Background: Because Optical Coherence Tomography (OCT) is widely used for diagnosis and monitoring of ocular pathology, especially in the elderly, we studied the influence of cataract on image quality and macular retinal thickness.

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

Results: Nuclear cataracts (n=12) provided better pre-operative scans (higher SNR/SS) than posterior (n=7) and cortical (n=10) cataracts (p < 0.004). Post- operatively SNR and SS increased significantly in all patients (p < 0.001). The SNR was better at discriminating poor from acceptable and good scans than SS (AROC: 0.879 and 0.810 resp.). Postoperative macular thickness overall showed a statistically 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 pre-operatively and macular thickness measurements are slightly increased post-operatively. In individual patients, OCT scans remain reliable for gross clinical interpretation, even in the presence of cataract.

Keywords: Cataract, Image Quality, Optical Coherence Tomography, Retinal thickness