Abstract
Purpose: :
Occlusive intraocular lenses (IOLs) are an effective therapeutic option in patients with intractable diplopia, visual confusion and unsightly leucocoria. Morcher occlusive IOLs permit high-levels of NIR transmission allowing quality SLO/OCT imaging of the posterior pole. It has not previously been determined whether occlusive IOLs produced by other manufacturers for clinical use equivalently transmit NIR light. It is therefore unclear as to whether this patient group can undergo SLO/OCT imaging for identifying life-threatening retinal and macular pathology, such as retinoblastoma or choroidal melanoma which may otherwise remain undetected.
Methods: :
We selected 6 black IOLs of 2 designs; 3 PMMA (Dr Schmidt Intraocularlinsen GmbH), and 3 Artisan iris-claw anterior chamber IOLs (Ophtec, Groningen). Each IOL was placed between a broad-spectrum white light source and a spectroradiometer to generate transmission spectra for each lens. Transmission in the NIR range was examined using an 850nm LED. SLO/OCT imaging (Spectralis; Heidelberg Engineering) was attempted through these occlusive IOLs in a model eye with simulated neurosensory retina, retinal vasculature and optic nerve.
Results: :
Artisan iris-claw and Dr Schmidt’s occlusive IOLs demonstrated total occlusion of all wavelengths of light, including in the NIR range in which all clinical SLO/OCT imaging systems operate. It was not possible to capture posterior segment SLO/OCT images through Artisan and Dr Schmidt’s occlusive IOLs in a model eye. Morcher occlusive IOLs transmitted high levels of NIR light, with consequent acquisition of high quality images using the Heidelberg Spectralis SLO/OCT imaging system in the model eye.
Conclusions: :
This novel study identifies for the first time that the property of NIR transmission which permits SLO/OCT imaging through occlusive IOLs is restricted to the Morcher range of occlusive IOLs. It is not possible to optically penetrate other occlusive IOLs currently in clinical use with NIR light. This finding may have a significant impact on the management of existing patients with occlusive IOL implants. Those patients with Morcher IOLs may be monitored and evaluated using SLO/OCT, but other occlusive IOLs may only be monitored by B-scan ultrasound, a less sensitive retinal imaging modality. This study may also impact on pre-operative occlusive IOL selection in eligible patients, particularly in those requiring strict posterior segment monitoring, such as in the setting of familial malignant melanoma or retinoblastoma in which a sensitive imaging modality such as SLO/OCT may be of considerable benefit.
Keywords: intraocular lens • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • strabismus