BMC Ophthalmology - Latest Articles

Rhegmatogenous retinal detachment in Scotland: research design and methodology

Danny Mitry — 2009-03-24T00:00:00Z

Background: Rhegmatogenous retinal detachment (RRD) is a potentially blinding condition and a common cause of ocular morbidity. Establishing an accurate estimate of disease incidence and distribution is an important first step in assessing the healthcare burden related to this condition and in subsequent planning and provision of treatment strategies. The aim of this study is to obtain a first estimate incidence of RRD in Scotland, to estimate the incidence of familial RRD and to describe the known associations of RRD within the study population.Methods/DesignWe have established a national prospective observational study seeking to identify and recruit all incident cases of RRD in the Scottish population over a 2 year period. After fully informed consent, all participants will have a blood sample taken and a full medical history and clinical examination performed including visual acuity, refraction, slit-lamp examination, intra-ocular pressure measurement and detailed fundal examination. We describe the study design and protocol. Conclusion: This study will provide the first estimate of the annual incidence of RRD in Scotland. The findings of this study will be important in estimating the burden of disease and in the planning of future health care policy related to this condition. This study will also establish a genetic resource for a genome wide association study to investigate if certain genetic variants predispose to RRD.

CD133+ adult human retinal cells remain undifferentiated in Leukemia Inhibitory Factor (LIF)

Debra Carter — 2009-02-23T00:00:00Z

Background: CD133 is a cell surface marker of haematopoietic stem and progenitor cells. Leukaemia inhibitory factor (LIF), sustains proliferation and not differentiation of embryonic stem cells. We used CD133 to purify adult human retinal cells and aimed to determine what effect LIF had on these cultures and whether they still had the ability to generate neurospheres. Methods: Retinal cell suspensions were derived from adult human post-mortem tissue with ethical approval. With magnetic automated cell sorting (MACS) CD133+ retinal cells were enriched from post mortem adult human retina. CD133+ retinal cell phenotype was analysed by flow cytometry and cultured cells were observed for proliferative capacity, neuropshere generation and differentiation with or without LIF supplementation. Results: We demonstrated purification (to 95%) of CD133+ cells from adult human postmortem retina. Proliferating cells were identified through BrdU incorporation and expression of the proliferation markers Ki67 and Cyclin D1. CD133+ retinal cells differentiated whilst forming neurospheres containing appropriate lineage markers including glia, neurons and photoreceptors. LIF maintained CD133+ retinal cells in a proliferative and relatively undifferentiated state (Ki67, Cyclin D1 expression) without significant neurosphere generation. Differentiation whilst forming neurospheres was re-established on LIF withdrawal. Conclusion: These data support the evidence that CD133 expression characterises a population of cells within the resident adult human retina which have progenitor cell properties and that their turnover and differentiation is influenced by LIF. This may explain differences in retinal responses observed following disease or injury.

Novel measures of cardiovascular health and its association with prevalence and progression of age-related macular degeneration

Catherine McCarty — 2008-12-22T00:00:00Z

Background: To determine if novel measures of cardiovascular health are associated with prevalence or progression of age-related macular degeneration (AMD). Methods: Measures of the cardiovascular system: included intima media thickness (IMT), pulse wave velocity (PWV), systemic arterial compliance (SAC), carotid augmentation index (AI). For the prevalence study, hospital-based AMD cases and population-based age- and gender-matched controls with no signs of AMD in either eye were enrolled. For the progression component, participants with early AMD were recruited from two previous studies; cases were defined as progression in one or both eyes and controls were defined as no progression in either eye. Results: 160 cases and 160 controls were included in the prevalence component. The upper two quartiles of SAC, implying good cardiovascular health, were significantly associated with increased risk of AMD (OR = 2.54, 95% CL = 1.29, 4.99). High PWV was associated with increased prevalent AMD. Progression was observed in 82 (32.3%) of the 254 subjects recruited for the progression component. Higher AI (worse cardiovascular function) was protective for AMD progression (OR = 0.30, 95%CL = 0.13, 0.69). Higher aortic PWV was associated with increased risk of AMD progression; the highest risk was seen with the second lowest velocity (OR = 6.22, 95% CL = 2.35, 16.46). Conclusion: The results were unexpected in that better cardiovascular health was associated with increased risk of prevalent AMD and progression. Inconsistent findings between the prevalence and progression components could be due to truly different disease etiologies or to spurious findings, as can occur with inherent biases in case control studies of prevalence. Further investigation of these non-invasive methods of characterizing the cardiovascular system should be undertaken as they may help to further elucidate the role of the cardiovascular system in the etiology of prevalent AMD and progression.

Traumatic Hyphaema: A report of 472 consecutive cases

Adeyinka Ashaye — 2008-11-26T00:00:00Z

Background: Strategies for prevention of eye injuries require knowledge of the cause of the injuries. This study was done to determine the patient characteristics, the cause of injury, and where cases of traumatic hyphaema that necessitated admission to a tertiary hospital occurred. This may enable an appropriate intervention in the prevention of such injuries. Methods: Retrospective case analysis of 472 patients with traumatic hyphaema admitted to the University College Hospital, Ibadan between January 1997 and December 2006. Results: The home was the single most frequent place of injury for all cases and for 75% of cases in children aged 0–10 years. Injuries that occurred at school comprised about one-fifth of cases. Sport-related injuries were uncommon.The most common activities preceeding injuries were play, corporal punishment and assault. Stones, sticks and whiplash were the agents that caused traumatic hyphaema. Occupational-related hyphaema that caused injuries was mostly in farmers and artisans, few of whom used protective goggles. The majority of patients were males. Children and young adults aged ≤ 20 years comprised 63.6% of patients. A total of 336 (76%) eyes had at least one surgical intervention. While 298 (73.2%) patients had visual acuity (VA) less than 6/60 at presentation, 143 (37.0%) of eyes had visual acuity (VA) < 6/60 3 months after injury. Conclusion: The injuries leading to traumatic hyphaema occur mostly at home and school, and frequently affect children and young adolescents. Over one-third resulted in blindness in the affected eye. The focus should be on prevention of stick-related eye injuries at these locations and improving access to eye health services for patients who sustained eye injuries.

Outcome of retinopathy of prematurity patients following adoption of revised indications for treatment

Aaron Alme — 2008-11-13T00:00:00Z

Background: The Early Treatment for Retinopathy of Prematurity study (ETROP), published in 2003, established new guidelines for treatment of retinopathy of prematurity (ROP) and demonstrated improved outcomes compared to previous guidelines. We examined outcomes before and after implementing the ETROP recommendations. Methods: A retrospective chart review was performed using records of infants who had laser ablations for ROP performed from January, 2000 through December, 2005. Data collected included date of birth; birth weight; estimated gestational age (EGA); grading of ROP; date of laser ablation; and outcome of laser surgery. Univariate association with threshold or prethreshold treatment (Pre-ETROP and Post-ETROP, respectively) were assessed using t-tests or Wilcoxon tests. Additional comparison between groups was performed using Fisher's exact tests. Results: 581 patients were examined before and 464 after December 2003. Of these, 29/581 (5% – Pre-ETROP Group) and 53/464 (11% – Post-ETROP Group) patients advanced to criteria requiring laser treatment respectively (P = 0.0001). The average estimated gestational age (EGA) at birth was 26.3 and 25.2 weeks, with an average birth weight of 888 and 707 grams for Pre and Post-ETROP Groups, respectively. Stage 5 retinal detachment (RD) developed in 10.3% of eyes in the Pre-ETROP Group and 1.9% of eyes in the Post-ETROP Group (P = 0.02). Conclusion: After the ETROP guidelines were implemented, there was a decrease from 10.3% to 1.9% of eyes developing Stage 5 retinal detachment, despite this group having a lower average EGA and lower average birth weight. These results underscore the importance of adoption of the Revised Indications.

Monte Carlo Simulation of Expected Outcomes with the AcrySof(R) Toric Intraocular Lens

Warren Hill — 2008-10-27T00:00:00Z

Background: To use a Monte Carlo simulation to predict postoperative results with the AcrySof® Toric lens, evaluating the likelihood of over- or under-correction using various toric lens selection criteria. Methods: Keratometric data were obtained from a large patient population with preoperative corneal astigmatism <= 2.50D (2,000 eyes). The probability distributions for toric marking accuracy, surgically induced astigmatism and lens rotation were estimated using available data. Anticipated residual astigmatism was calculated using a Monte Carlo simulation under two different lens selection scenarios. Results: This simulation demonstrated that random errors in alignment, surgically induced astigmatism and lens rotation slightly reduced the overall effect of the toric lens. Residual astigmatism was statistically significantly higher under the simulation of surgery relative to an exact calculation (p < 0.05). The simulation also demonstrated that more aggressive lens selection criteria could produce clinically significant reductions in residual astigmatism in a high percentage of patients. Conclusion: Monte Carlo simulation suggests that surgical variability and lens orientation/rotation variability may combine to produce small reductions in the correction achieved with the AcrySof® Toric® IOL. Adopting more aggressive lens selection criteria may yield significantly lower residual astigmatism values for many patients, with negligible overcorrections. Surgeons are encouraged to evaluate their AcrySof® Toric® outcomes to determine if they should modify their individual lens selection criteria, or their default surgically induced astigmatism value, to benefit their patients.

A novel approach to glaucoma screening and education in Nepal

Suman Thapa — 2008-10-26T00:00:00Z

Background: Glaucoma is a major cause of blindness worldwide and an increasingly significant global health problem. Glaucoma prevention and management efforts have been challenging due to inherent difficulty in developing a simple and cost-effective screening plan, limited access to health care and educational resources, poverty, and inadequate knowledge of the disease, particularly in developing countries. Starting in 2004 the Tilganga Eye Centre in Kathmandu, Nepal has provided targeted glaucoma screening, treatment, and education through a combination of clinical outreach programs and educational activities for patients. Methods: A simple, age-based glaucoma screening algorithm was incorporated into three one-day cataract screening clinics. Using this algorithm, patients who were newly diagnosed with glaucoma were referred to TEC, where medication and surgery were provided free of charge through private donor funding. In addition, we describe two ongoing educational programs for increasing glaucoma awareness: an annual Glaucoma Awareness Week (which includes free screening, treatment, and counseling), and a repeating lecture series which generates new counselors. Results: From 2004 to 2007 screening at the annual Glaucoma Awareness Week resulted in the diagnosis of 120 individuals with glaucoma, or 7.6% of total registrants. Attendance increased annually with a trend toward an increasing number of returning patients but a decreasing percentage of newly diagnosed patients, though the absolute numbers have remained relatively stable (range 21 to 38). Data from the three one-day screening clinics in 2006 show that approximately 2 to 4% of patients 50 years of age or older per clinic were newly diagnosed with POAG. Conclusion: This multi-faceted approach appears to successfully identify individuals with glaucoma and provide treatment to those who would otherwise not be able to afford it. While more data is needed to validate this model, specifically regarding the effectiveness of educational activities, long-term visual outcomes, and medication compliance, it may serve as a useful framework for other developing countries with similarly limited resources.

Matrix metalloproteinases and their tissue inhibitors after selective laser trabeculoplasty in pseudoexfoliative secondary glaucoma

Mauro Cellini — 2008-10-21T00:00:00Z

Background: The aim of this study was to assess changes in metalloproteinases (MMP-2) and tissue inhibitor of metalloproteinases (TIMP-2) following selective laser trabeculoplasty (SLT) in patients with pseudoexfoliative glaucoma (PEXG). Methods: We enrolled 15 patients with PEXG and cataracts (PEXG-C group) and good intraocular pressure (IOP) controlled with β-blockers and dorzolamide eye drops who were treated by cataract phacoemulsification and 15 patients with pseudoexfoliative glaucoma (PEXG-SLT group). The PEXG-SLT patients underwent a trabeculectomy for uncontrolled IOP in the eye that showed increased IOP despite the maximum drug treatment with β-blockers and dorzolamide eye drops and after ineffective selective laser trabeculoplasty (SLT). The control group consisted of 15 subjects with cataracts. Aqueous humor was aspirated during surgery from patients with PEXG-C, PEXG-SLT and from matched control patients with cataracts during cataract surgery or trabeculectomy. The concentrations of MMP-2 and TIMP-2 in the aqueous humor were assessed with commercially available ELISA kits. Results: In PEXG-SLT group in the first 10 days after SLT treatment a significant reduction in IOP was observed: 25.8 ± 1.9 vs 18.1.0 ± 1.4 mm/Hg (p < 0.001), but after a mean time of 31.5 ± 7.6 days IOP increased and returned to pretreatment levels: 25.4 ± 1.6 mm/Hg (p < 0.591). Therefore a trabeculectomy was considered necessary.The MMP-2 in PEXG-C was 57.77 ± 9.25 μg/ml and in PEXG-SLT was 58.52 ± 9.66 μg/ml (p < 0.066). TIMP-2 was 105.19 ± 28.53 μg/ml in PEXG-C and 105.96 ± 27.65 μg/ml in PEXG-SLT (p < 0.202). The MMP-2/TIMP-2 ratio in the normal subjects was 1.11 ± 0.44. This ratio increase to 1.88 ± 0.65 in PEXG-C (p < 0.001) and to 1.87 ± 0.64 in PEXG-SLT (p < 0.001). There was no statistically significant difference between the PEXG-C and PEXG-SLT ratios (p < 0.671). Conclusion: This case series suggest that IOP elevation after SLT can be a serious adverse event in some PEXG patients. The IOP increase in these cases would be correlated to the failure to decrease the TIMP-2/MMP-2 ratio.Trial registrationCurrent Controlled Trials ISRCTN79745214

Refractive change following pseudophakic vitrectomy: a retrospective review

Sinead Byrne — 2008-10-13T00:00:00Z

Background: To assess the occurrence and magnitude of refractive change in pseudophakic eyes undergoing 20 gauge pars plana vitrectomy without scleral buckling and to investigate possible aetiological factors. Methods: Retrospective case note review of 87 pseudophakic eyes undergoing 20 gauge pars plana vitrectomy for a variety of vitreo-retinal conditions over a three-year period. Anterior chamber depth (ACD) was measured before and after vitrectomy surgery in 32 eyes. Forty-three pseudophakic fellow eyes were used as controls. Results: Eighty-seven eyes (84 patients) were included in the study. Mean spherical equivalent refraction prior to vitrectomy was -0.20 dioptres, which changed to a mean of -0.65 dioptres postoperatively (standard deviation of refractive change 0.59, range-2.13 to 0.75 dioptres) (p < 0.001). Sixty-one of the 87(70%) eyes experienced a myopic shift and 45(52%) eyes had a myopic shift of -0.5 dioptres or more. Mean fellow eye refraction was -0.19 dioptres preoperatively and -0.17 dioptres postoperatively (p = 0.14)(n = 37)Mean ACD preoperatively was 3.29 mm and postoperatively 3.27 mm (p = 0.53) (n = 32) and there was no significant change in ACD with tamponade use. Regression analysis revealed no statistically significant association between changes in anterior chamber depth, as well as a wide variety of other pre-, intra and postoperative factors examined, and the refractive change observed. Conclusion: Significant refractive changes occur in some pseudophakic patients undergoing 20 g pars plana vitrectomy. The mean change observed was a small myopic shift but the range was large. The aetiology of the refractive change is uncertain.

Treatment of Branch Retinal Vein Occlusion induced Macular Edema with Bevacizumab

Mathias Abegg — 2008-09-29T00:00:00Z

Background: Branch retinal vein occlusion is a frequent cause of visual loss with currently insufficient treatment options. We evaluate the effect of Bevacizumab (Avastin®) treatment in patients with macular edema induced by branch retinal vein occlusion. Methods: Retrospective analysis of 32 eyes in 32 patients with fluorescein angiography proven branch retinal vein occlusion, macular edema and Bevacizumab treatment. Outcome measures were best corrected visual acuity in logMAR and central retinal thickness in OCT. Results: Visual acuity was significantly better 4 to 6 weeks after Bevacizumab treatment compared to visual acuity prior to treatment (before 0.7 ± 0.3 and after 0.5 ± 0.3; mean ± standard deviation; p < 0.01, paired t-test). Gain in visual acuity was accompanied by a significant decrease in retinal thickness (454 ± 117 to 305 ± 129 μm, p < 0.01, paired t-test). Follow up (170, 27 – 418 days; median, range) shows that improvement for both visual acuity and retinal thickness last for several months after Bevacizumab use. Conclusion: We present evidence that intravitreal Bevacizumab is an effective and lasting treatment for macular edema after branch retinal vein occlusion.