Ophthalmology (West of England Eye Unit)

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Research outputs from the West of England Eye Unit (WEEU) team.

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    The Role of Insulin-like Growth Factor (IGF) System in the Corneal Epithelium Homeostasis-From Limbal Epithelial Stem Cells to Therapeutic Applications
    (MDPI, 2024-03-01) Woronkowicz, M.; Roberts, H.; Skopinski, P.
    The corneal epithelium, comprising three layers of cells, represents the outermost portion of the eye and functions as a vital protective barrier while concurrently serving as a critical refractive structure. Maintaining its homeostasis involves a complex regenerative process facilitated by the functions of the lacrimal gland, tear film, and corneal nerves. Crucially, limbal epithelial stem cells located in the limbus (transitional zone between the cornea and the conjunctiva) are instrumental for the corneal epithelium integrity by replenishing and renewing cells. Re-epithelialization failure results in persistent defects, often associated with various ocular conditions including diabetic keratopathy. The insulin-like growth factor (IGF) system is a sophisticated network of insulin and other proteins essential for numerous physiological processes. This review examines its role in maintaining the corneal epithelium homeostasis, with a special focus on the interplay with corneal limbal stem cells and the potential therapeutic applications of the system components.
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    The Royal College of Ophthalmologists' National Ophthalmology Database Study of Cataract Surgery: Report 12, Risk factors for suprachoroidal haemorrhage during cataract surgery
    (Nature, 2023-06-01) Stewart, S.; Gruszka-Goh, M. H.; Neo, Y. N.; Braga, A. J.; de Klerk, T. A.; Lindfield, D.; Nestel, A.; Donachie, P. H. J.; Buchan, J. C.
    OBJECTIVE: To establish the incidence of acute intraoperative suprachoroidal haemorrhage (AISH) during cataract surgery and identify the risk factors for this complication. METHODS: Data from the Royal College of Ophthalmologists' National Ophthalmology Database was analysed. During the 11-year study period, from 01/04/2010 to 31/03/2021, 709 083 operations performed on 498 170 patients from 65 centres were eligible for inclusion. RESULTS: AISH occurred in 0.03% (204/709 083, approximately 1 in 3 500) of eligible cataract operations performed during the study period. Posterior capsule rupture was the risk factor most strongly associated with AISH (OR: 17.6, 95% CI: 12.4-24.9, p < 0.001). Other ocular risk factors identified were raised intraocular pressure (IOP) preoperatively (OR: 3.7, 95% CI: 2.5-5.5, p < 0.001), glaucoma (OR: 1.7, 95% CI: 1.2-2.4, p = 0.004). Risk increased with age and patients aged over 90 years were at greatest risk (OR: 6.7, 95% CI: 3.5-12.8, p < 0.001). The addition of intracameral anaesthetic when performing surgery under topical anaesthetic appears to be protective (OR: 0.5, 95% CI: 0.3-0.8, p = 0.003), compared to topical anaesthetic alone. There was a 16-fold increase in the incidence of vision loss when AISH occurred. CONCLUSIONS: The risk of AISH during modern cataract surgery is approximately 1 in 3 500 and is associated with a significant increase in the risk of vision loss should it occur. Posterior capsule rupture is the risk factor most strongly associated with AISH. Preoperative IOP control is a modifiable risk factor. The use of intracameral anaesthesia may reduce the risk of AISH.
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    Time and Motion Studies to assess surgical productivity in cataract theatre lists within the National Health Service: Immediate Sequential Bilateral Cataract Surgery versus Delayed Sequential Bilateral Cataract Surgery
    (Nature, 2023-06-01) Naderi, K.; Lam, C. F. J.; Low, S.; Bhogal, M.; Jameel, A.; Theodoraki, K.; Lai, L.; Garcia, L. O.; Roberts, H.; Robbie, S.; O'Brart, D.
    BACKGROUND: To compare productivity of National Health Service cataract lists performing unilateral cataract (UC) surgery vs Immediate Sequential Bilateral Cataract Surgery (ISBCS). METHODS: Five 4-hour lists with ISBCS cases and five with UC were observed using time and motion studies (TMS). Individual tasks and timings of each staff member in theatre was recorded by two observers. All operations were performed by consultant surgeons under local anaesthesia (LA). RESULTS: Median number of eyes operated per 4-hour list was 8 (range 6-8) in the ISBCS group and 5 (5-7) in the UC group (p = 0.028). Mean total theatre time (defined as time between the entry of the first patient and the exit of the last patient from theatre) was 177.12 (SD 73.62) minutes in the ISBCS group and 139.16 (SD 47.73) minutes in the UC group (p = 0.36). Mean time to complete two consecutive unilateral cataract surgery operations was 48.71 minutes compared to 42.23 minutes for a single ISBCS case (13.30% time saved). Based on our collected TMS data, a possible 5 consecutive ISBCS cases and 1 UC (total 11 cataract surgeries) could be performed during a four-hour theatre session, with a theatre utilisation quotient of 97.20%, contrasting to nine consecutive UC, with a theatre utilisation quotient of 90.40%. DISCUSSION: Performing consecutive ISBCS cases under LA on routine cataract surgery lists can increase surgical efficiency. TMS are a useful way to investigate surgical productivity and test theoretical models for efficiency improvements.
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    Estimating the rate of severe visual loss (wipe-out) following cataract surgery, a British Ophthalmological Surveillance Unit (BOSU) study
    (Nature, 2023-06-01) Ramsden, C.; Shweikh, Y.; Kam, R.; Bunce, C.; Foot, B.; Viswanathan, A.
    BACKGROUND: A sudden, irreversible reduction in visual acuity ('wipe-out') is a feared complication of cataract surgery. Current literature on wipe-out is limited in quantity and quality, and largely predates modern cataract surgery and imaging techniques. The objectives of our study were to estimate the incidence of wipe-out and to identify potential risk factors. METHODS: We prospectively collated cases of wipe-out occurring in the UK during a 25-month study period using the British Ophthalmic Surveillance Unit reporting system. A total of 21 potential cases of wipe-out were reported, 5 of which met all inclusion and exclusion criteria. RESULTS: The estimated incidence of wipe-out during the study period was 0.00000298, or approximately 3 cases per million cataract operations. All cases of wipe-out occurred exclusively in patients with advanced glaucoma (mean deviation -21.0 decibels or worse in the operated eye), with an over-representation of black people (40%) in our case series. A prior diagnosis of retinal vein occlusion (60%) and elevated post-operative IOP (40%) were more common among individuals suffering from wipe-out compared to the general population, suggesting these factors may contribute to the pathogenesis of wipe-out. CONCLUSIONS: Our study shows that wipe-out is a rare complication, affecting approximately 3 per million undergoing cataract surgery. Patients with advanced glaucoma, black patients, and those with previous retinal vein occlusions may be at greater risk of wipe-out. We hope that the findings of our study will be used to help inform treatment decision-making and the cataract surgery consent process.
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    Comparison of repeat penetrating keratoplasty, DSAEK and DMEK for the management of endothelial failure of previous PK
    (Nature, 2023-06-01) Roberts, H. W.; de Benito-Llopis, L.
    PURPOSE: To compare the clinical outcomes of repeat PK, DSAEK-on-PK or DMEK-on-PK for the management of endothelial failure of previous penetrating keratoplasty. DESIGN: Retrospective, interventional consecutive case series. PARTICIPANTS: 104 consecutive eyes of 100 patients requiring a second keratoplasty for endothelial failure of their primary penetrating keratoplasty performed between September 2016 and December 2020. INTERVENTION: Repeat keratoplasty. MAIN OUTCOME MEASURES: Survival and visual acuity at 12 and 24 months, rebubbling rate and complications. RESULTS: Repeat PK was performed in 61/104 eyes (58.7%), DSAEK-on-PK was performed in 21/104 eyes (20.2%) and DMEK-on-PK was performed in 22/104 eyes (21.2%). Failure rates in the first 12 and 24 months were 6.6% and 20.6% for repeat PKs compared to 19% and 30.6% for DSAEK and 36.4% and 41.3% for DMEK. For those grafts surviving 12 months, the chances of surviving to 24 months were greatest for DMEK-on-PK at 92% vs 85% each for redo PK and DSAEK-on-PK. Visual acuity at one year was logMAR 0.53 ± 0.51 in the redo PK group, 0.25 ± 0.17 for DSAEK-on-PK and 0.30 ± 0.38 for DMEK-on-PK. 24-month outcomes were 0.34 ± 0.28, 0.08 ± 0.16, and 0.36 ± 0.36 respectively. CONCLUSIONS: DMEK-on-PK has a greater failure rate in the first 12 months than DSAEK-on-PK which has a greater failure rate than redo PK. However, the 2-year survival rates in our series for those already surviving 12 months were greatest for DMEK-on-PK. There was no significant difference in visual acuity at 12 or 24 months. Careful patient selection is needed by experienced surgeons to determine which procedure to offer to patients.