Abstract
Purpose: :
Photo-oxidative stress is believed to play a role in AMD pathogenesis. Macular pigment (MP), consisting of lutein (L), zeaxanthin (Z) and meso-Z, has a max absorption at 460nm and protects the retina from photo-oxidative injury. We investigated whether the blue light filtering properties of the Alcon AcrySof Natural intraocular lens (ANIOL) implanted during cataract surgery impacts on MP optical density (MPOD).
Methods: :
44 patients scheduled for cataract surgery were recruited. All patients had pre-op best corrected visual acuity (BCVA) of at least 0.5logMAR in the study eye. Patients were randomised to have either the standard Alcon AcrySof 3-piece acrylic intraocular lens (AIOL) or the ANIOL. Spatial profile of MPOD was measured by customised heterochromatic flicker photometry (cHFP) 1 week pre-op and 1 week post-op, and at 3, 6 and 12 months post-op. Serum concentrations of L and Z were measured at each visit.
Results: :
There was a significant positive correlation between MPOD values at 0.25deg recorded 1 week pre- and post-op in eyes implanted with an AIOL (r=0.915,p<0.01;paired samples t-test:p=0.631) and in those implanted with an ANIOL (r=0.868,p<0.05;paired samples t-test:p=0.719). MPOD increased significantly after 3 months in the ANIOL group (p<0.05). There was a significant time effect for serum Z over the study period (p<0.05).
Conclusions: :
cHFP can reliably measure MPOD spatial profile in the presence of cataract, and cataract surgery does not artefactually alter MPOD readings. This study provides evidence that implanting a blue-light filtering IOL is associated with augmentation of MPOD in the absence of raised serum L and Z concentrations, consistent with the view that filtering blue light limits photo-oxidative retinal injury, and a consequential depletion of MP. However, further study is required to assess whether these findings are associated with a reduced risk of AMD.
Keywords: macular pigment • intraocular lens • cataract