Timo Eppig1, Corinna Spira2, Themistoklis Tsintarakis2, Moatasem El-Husseiny2, Alan Cayless2, Marc Müller2, Berthold Seitz2, Achim Langenbucher2. 1. From the Institute of Experimental Ophthalmology (Eppig, Langenbucher), Saarland University, Homburg/Saar, Germany; Department of Ophthalmology (Spira, Tsintarakis, El-Husseiny, Müller, Seitz), Saarland University Medical Center, Homburg/Saar, Germany; Department of Physical Sciences (Cayless), Open University, Milton Keynes, Buckinghamshire, United Kingdom. Electronic address: timo.eppig@uks.eu. 2. From the Institute of Experimental Ophthalmology (Eppig, Langenbucher), Saarland University, Homburg/Saar, Germany; Department of Ophthalmology (Spira, Tsintarakis, El-Husseiny, Müller, Seitz), Saarland University Medical Center, Homburg/Saar, Germany; Department of Physical Sciences (Cayless), Open University, Milton Keynes, Buckinghamshire, United Kingdom.
Abstract
PURPOSE: To analyse the optical effect of an artificial hole in the optic centre of posterior chamber phakic intraocular lenses. SETTING: Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany. DESIGN: Experimental simulation study. METHODS: Four eye models with an ametropia of -4 D, -8 D, +4 D, and +8 D were created in the ray tracing software ASAP. Refractive correction of these models was implemented with a model of an Implantable Collamer Lens (ICL). Each eye was set up twice with 1 eye receiving a conventional ICL without a central hole and the second an ICL with a central hole. Ray bundles were traced for lateral visual field angles from 0 to 60 degrees in steps of 1 degree. Ray propagation and retinal illumination were then compared between the 2 ICL models. RESULTS: All eye models showed ghost images originating from the anterior surface of the ICL. Eye models with the ICL with central hole showed additional light spots in the peripheral areas of the retina originating from reflections at the cylindrical wall of the central hole in the ICL. The average intensity of ghost images in the temporal retinal hemisphere was between 30 and 40 dB less than the maximum intensity of the primary image. CONCLUSION: A central hole within a posterior chamber phakic intraocular lens may cause stray light and ghost images (positive dysphotopsia) although the on-axis visual quality of the eye with the ICL is mostly unaffected. FINANCIAL DISCLOSURE: The authors have no financial interest in any of the material presented in this paper.
PURPOSE: To analyse the optical effect of an artificial hole in the optic centre of posterior chamber phakic intraocular lenses. SETTING: Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany. DESIGN: Experimental simulation study. METHODS: Four eye models with an ametropia of -4 D, -8 D, +4 D, and +8 D were created in the ray tracing software ASAP. Refractive correction of these models was implemented with a model of an Implantable Collamer Lens (ICL). Each eye was set up twice with 1 eye receiving a conventional ICL without a central hole and the second an ICL with a central hole. Ray bundles were traced for lateral visual field angles from 0 to 60 degrees in steps of 1 degree. Ray propagation and retinal illumination were then compared between the 2 ICL models. RESULTS: All eye models showed ghost images originating from the anterior surface of the ICL. Eye models with the ICL with central hole showed additional light spots in the peripheral areas of the retina originating from reflections at the cylindrical wall of the central hole in the ICL. The average intensity of ghost images in the temporal retinal hemisphere was between 30 and 40 dB less than the maximum intensity of the primary image. CONCLUSION: A central hole within a posterior chamber phakic intraocular lens may cause stray light and ghost images (positive dysphotopsia) although the on-axis visual quality of the eye with the ICL is mostly unaffected. FINANCIAL DISCLOSURE: The authors have no financial interest in any of the material presented in this paper.