To demonstrate feasibility of macular cube optical coherence tomography (OCT) scanning and intraoperative central retinal thickness (CRT) measurement with a novel combination of a Carl Zeiss MeditecTM Cirrus HD-OCTTM system adapted to the optical pathway of a Zeiss OPMI VISU 200TM surgical microscope (Intra-OP-OCT) during uneventful small-incision cataract surgery.
In 50 subjects, 512 × 128 high resolution macular cube scans were performed during surgery, before and immediately after intraocular lens (IOL) implantation. Interobserver variability was calculated from measurements of two observers. In four subgroups of healthy, diabetic, hypertensive and diabetic and hypertensive (both) subjects, measurement reliability and reproducibility is demonstrated.
Scans of 41 eyes (diabetes n = 11; hypertension n = 15 or both n = 26 and healthy n = 15) with sufficient quality for CRT measurement by both observers. Intra-observer precision was 1 μm, mean interobserver difference was −0.9 μm, with limits of agreement from + 15.1 to − 12.4 μm. Preoperative CRT (mean ± SD, μm) of 210 ± 30 (121–286) increased significantly by 8.2 ± 11.7 to 218 ± 27 (154–296) (p < 0.001). No significant difference was observed between the subgroups (p > 0.05).
OCT scanning and CRT measurement using Intra-OP-OCT is feasible. A significant increase in CRT of 8 μm immediately after surgery was detected but no difference between the subgroups. Intra-OP-OCT offers novel, highly reproducible information about structural behaviour of the retina during small-incision cataract surgery. Intra-OP-OCT can contribute with precise measurements for better understanding of macular changes following cataract surgery, relevant in patients with macular diseases needing cataract surgery.