Refractive management of patients undergoing cataract surgery. The development of pre and post-operative refractive management guidelines for patients undergoing cataract surgery in the UK

View/ Open
PhD Thesis (8.450Mb)
Download
Publication date
2022Author
Charlesworth, EmilyKeyword
Cataract surgeryTarget refraction
Refractive stability
Delphi study
Systematic review
Meta-analysis
Clinical vignette study
Refractive management
Rights

The University of Bradford theses are licenced under a Creative Commons Licence.
Institution
University of BradfordDepartment
School of Optometry and Vision Science. Faculty of Life SciencesAwarded
2022
Metadata
Show full item recordAbstract
Cataract surgery is the most commonly performed surgery within the UK with 400,000 surgeries performed each year. Currently no guidelines exist for clinicians regarding target refraction discussions, spectacle provision post-operatively and driving advice following surgery. The PhD aimed to start the process of developing pre- and post-operative management guidelines for patients developed by both optometrists and ophthalmologists which could then be disseminated to both professions in the hope of improving the overall outcome of surgery. The current literature highlighted target refraction discussions were lacking or non-existent which left some myopes dissatisfied after surgery due to an emmetropic target refraction leaving them unable to read without glasses as they did prior to surgery. Target refraction discussions were found to be linked with years of experience and this needs further exposure in continuing professional development. Post-operative driving advice was found to be inconsistent and vary between practitioners and between optometry and ophthalmology. Advice was found to vary from driving “immediately” following surgery up to 6 weeks post-operatively. Re-analysis of (de Juan et al. 2013) data during our systematic review and meta-analysis found refraction to be stable 1-2 weeks following surgery for 93% of patients. It was found a large change between pre- and post-surgery cylindrical power/axis may be an indicator that refractive stability has not occurred. Although this study had limitations it confirmed refraction is stable sooner than the current guidelines of 4-6 weeks. Finally, we used a Delphi process to develop refractive management guidelines with a total of fifteen recommendations finalised.Type
ThesisQualification name
PhDCollections
Related items
Showing items related by title, author, creator and subject.
-
New methodology for predicting vertical atmospheric profile and propagation parameters in sub-tropical Arabian Gulf regionAbouAlmal, A.; Abd-Alhameed, Raed; Jones, Steven M.R.; Al-Ahmad, Hussain (2015-07-06)A new simplified approach is proposed to evaluate the vertical refractivity profile within the lowest 1 km of atmosphere from the analysis of surface refractivity, Ns, in areas where upper air data are not available. Upper-air measurements from the nearest available radiosonde location with similar surface profile to these sites are utilized. The profiles of Ns and refractivity extrapolated to sea level, No, obtained from surface meteorological data using both fixed stations and radiosonde are investigated and compared. Vertical refractivity gradient, ΔN, is evaluated at three atmospheric layer heights within the first kilometer above the ground in addition to propagation parameters relevant to each atmospheric layer. At six sites, different approaches are compared for the analysis of three important parameters; namely effective earth radius factor, k, anomalous propagation probability parameter, β0, and point refractivity gradient at 65 m not exceeded for 1% of time, dN1. The k-factor parameter is investigated using a new weighted average approach of ΔN at 65 m, 100 m and 1 km layers above the ground. The results are compared with the latest ITU maps and tables for the same area.
-
Analysis and modelling of the impact of anomalous propagation on terrestrial microwave links in a subtropical region, based on long-term measurements. Statistical analysis of long-term meteorological and signal strength measurements in a subtropical region and investigation of the impact of anomalous refractivity profiles on radio propagation in terrestrial microwave wireless systemsAbd-Alhameed, Raed; Jones, Steven M.R.; Al-Ahmad, Hussain; Aboualmal, Abdulhadi M.A. (University of BradfordSchool of Engineering, Design and Technology, 2015)Prevailing propagation phenomena in certain areas play a vital role in deciding terrestrial wireless systems performance. Vertical refractivity profile below 1 km is a critical parameter for designing reliable systems; noting that there is a shortage of upper-air data worldwide. Anomalous phenomena may cause severe signal fading and interference beyond the horizon. The objectives of this thesis are to investigate dominant refractive conditions in the subtropical Arabian Gulf region, develop new approaches and empirical models for evaluating vertical refractivity profiles and relevant propagation parameters in the low troposphere, and to examine the impact of frequently experienced anomalous phenomena on terrestrial microwave links. Twenty-three years of meteorological measurements, from 1990 to 2013, are utilized using spatially separated surface stations and a single radiosonde in the United Arab Emirates (UAE). Profiles of sea level, surface and upper refractivity components are statistically analysed. Three major atmospheric layers; namely 65 m, 100 m and 1 km above the ground are studied to analyse relevant propagation parameters such as sub-refraction, super-refraction, anomalous propagation probability parameter β0 and point refractivity gradient not exceeded for 1% of time. The effective earth radius factor k is investigated using a new weighted averaged approach. In addition, the seasonal structure of atmospheric ducting is dimensioned within 350 m layer above ground. Finally, microwave measurement campaign is conducted using multiple radio links operating in UAE using various frequency bands. The link budget simulations are compared with the signal strength measurements. Fading scenarios are studied against the observed anomalous conditions and several recommendations are concluded.
-
Seasonal statistics of anomalous propagation in United Arab EmiratesAbouAlmal, A.; Abd-Alhameed, Raed; Jones, Steven M.R. (2014)In this paper, the seasonal variations of vertical refractivity gradients and statistics of anomalous Refractive Conditions in the United Arab Emirates (UAE) have been analyzed. Nine years of local radiosonde meteorological data, from 1997 to 2005, for the lowest atmospheric layer above the ground surface have been used. Monthly variations and cumulative distributions of refractivity gradients in the first 100 meters of the atmosphere are presented.