VOL: 42 ISSUE: 4 MONTH: APRIL 2016
MACULAR DISEASE DETECTION BEFORE CATARACT SURGERY
A biometry device featuring swept-source optical coherence tomography (SS-OCT) appears to be useful for detecting macular pathologies prior to cataract surgery, especially for intraretinal fluid and macular holes. The consecutive case series included 125 eyes of patients with or without macular disease. All patients were scanned using the new biometry device (IOLMaster 700), which allows a 1.0mm central retinal scan using SS-OCT technology. Also, all eyes were assessed using a dedicated retinal OCT device (RTVue) on the same day. Of the 125 eyes included, five were excluded from the analysis, 65 had a macular disease, and 55 were healthy. The sensitivity of the biometry device was moderate (between 42 per cent and 68 per cent), and the specificity was high (89 per cent to 98 per cent). While the OCT biometry device was beneficial in terms of detecting macular holes and intraretinal fluid, other macular pathologies, such as atrophy and epiretinal membranes, were missed in several cases. Therefore, conventional spectral-domain OCT is still necessary to refine the presumed diagnosis made based on scans from the biometry device.
N Hirnschall et al, JCRS, “Macular disease detection with a swept-source optical coherence tomography-based biometry device in patients scheduled for cataract surgery”, Volume 42, Issue 4, 530-535.
3D TORIC IOL ALIGNMENT
Accurate alignment of toric intraocular lenses (IOLs) at the intended meridian is crucial to achieve intended astigmatism correction. A single degree of off-axis rotation produces a loss of up to 3.3 per cent of intended cylinder correction. A novel 3D computer-guided system (TrueVision) showed good accuracy in guiding the alignment of toric IOLs in femtosecond laser-assisted cataract surgery (FLACS). The 3D system used the anterior keratometry values to create an optimised plan for the toric IOL alignment. Intrastromal marks were created by the femtosecond laser at the intended toric meridian, guided by manual ink marks placed at the 3 o'clock and 9 o'clock limbus with the patient sitting upright. Intraoperatively, the 3D system was used to align the IOL and measure the angular position of the femtosecond marks relative to the IOL meridian. The 3D system proved equal in accuracy to manual marking for IOL alignment. The new system is a step in evolution towards a system that fully automates the entire process, including measurement of the anterior and posterior cornea, provision of algorithms for the IOL selection, and intraoperative guidance of the IOL. Such an approach would save time and improve accuracy, but would also increase costs, the researchers conclude.
I de Oca et al, JCRS, “Accuracy of toric intraocular lens axis alignment using a 3-dimensional computer-guided visualization system”, Volume 42, Issue 4, 550-555.