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To investigate the role of nanosecond laser technology in rejuvenating transport in the aged outer retina.

Heng, LZ; (2014) To investigate the role of nanosecond laser technology in rejuvenating transport in the aged outer retina. Doctoral thesis , UCL (University College London). Green open access

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Abstract

The transport capacity of the retina plays a major role in maintaining health of the photoreceptors cells. In particular, age-related changes in the Bruch’s membrane(BrM) correspond to a decrease in the transport of nutrients and waste products across the Bruch’s. Matrix metalloproteinase(MMP), an extracellular matrix regulator was found to be sequestrated in aged BrM, with decreased availability for activity. Hence, it was hypothesized that a plausible target to rejuvenate the transportation across BrM and prevent the age-related processes in the macular was to increase the activity of MMP in BrM. Previous studies have shown an increase in MMP release secondary to RPE migration initiated by deliberate injury using lasers. However,conventional lasers causes collateral photoreceptor cell damage via primary thermal denaturation and secondary apoptosis. The nanosecond laser used in the present study with its speckled beam configuration and nanosecond pulse is designed to limit the primary damage profile. The main objectives of this PhD was to determine if this novel laser was a viable option to improve transport across BrM while preserving photoreceptor function, further to ascertain its efficacy and safety for use in human subjects to delay or prevent onset of AMD. Laboratory results from this thesis confirmed the importance of MMPs but demonstrated the inadequcy of the speckled beam configuration at higher energy levels. Corroborative clinical results also found beam profile inadequacy with the suprathreshold nature of the current energy-dose but desmonstrated minmal collateral damage. Clinical evaluation found a short term improvement of visual function. It may be concluded this novel laser has potential to be used as a therapeutic modality to delay AMD, but further work needs to be done to address the current issues of beam configuration and energy dosing for its optimal use in the future.

Type: Thesis (Doctoral)
Title: To investigate the role of nanosecond laser technology in rejuvenating transport in the aged outer retina.
Open access status: An open access version is available from UCL Discovery
Language: English
Keywords: nanosecond, laser, Age Related Macular Degeneration, Retina, Bruch's membrane, Hydraulic Conductivity, Matrix Metalloproteinase
UCL classification: UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: http://discovery.ucl.ac.uk/id/eprint/1456743
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