Dr Laura Downie
BOptom PhD(Melb) PGCertOcTher FACO FAAO DipMus(Prac) AMusA
Association between reproductive factors and AMD in post-menopausal women
A population-based, cross-sectional study conducted in Korea has described an association between female reproductive factors and the development of late-stage AMD in post-menopausal women.
A nationally-representative dataset that included reproductive and ocular health information for 4,377 post-menopausal women (aged = 50 years) was analysed from the 2010-2012 Korea National Health and Nutrition Examination survey.
Prevalence rates of early and late AMD were 11.2 per cent (95% confidence interval [CI], 10.1-12.5) and 0.8 per cent (95% CI, 0.5-1.2), respectively. Multivariate logistic regression analyses revealed that age (OR, 1.12 per one year), duration of lactation (OR, 0.91 per six months), and duration of use of oral contraceptive pills (OCP) (OR, 1.10 per six months) were associated factors for late-stage AMD.
The authors concluded that after controlling for confounders, a longer duration of lactation appeared to protect against the development of late AMD. A longer duration of OCP use was associated with a higher risk of late-stage AMD.
PLoS One 2014; 9: 7: e.102816.
Preventing pseudophakic cystoid macular oedema following cataract surgery
A review has found weak evidence for the use of topical non-steroidal anti-inflammatory drug (NSAIDs) therapy in controlling post-operative inflammation after cataract surgery.
The systematic review has compared the efficacy of topical corticosteroid treatment with topical non-steroidal anti-inflammatory drugs therapy, following uncomplicated cataract surgery. The main outcome measure was defined as post-operative inflammation and pseudophakic cystoid macular oedema (PCME), in patients undergoing phacoemulsification with posterior chamber intraocular lens implantation for age-related cataract.
A total of 15 randomised clinical trials were identified from the systematic literature search. Post-operative inflammation was reported to be less in patients randomised to NSAIDs. The prevalence of PCME was significantly higher in the corticosteroid group than in the NSAID group (3.8 per cent vs 25.3 per cent; risk ratio: 5.35, 95% CI, 2.95-9.76). There was no significant difference in the number of adverse events between the two treatment groups.
It was concluded that there was low to moderate quality of evidence that topical NSAIDs are more effective in controlling post-operative inflammation after cataract surgery. High-quality evidence was found to support the premise that topical NSAIDs are more effective than topical corticosteroids in preventing PCME.
The authors recommended the use of topical NSAIDs to prevent inflammation and PCME after routine cataract surgery.
Ophthalmology 2014; June 13. Epub ahead of print.
Smoking deception and AMD
Smoking deception rates for patients with AMD were found to be higher than generally reported in the US population.
Smoking has been consistently identified as the most important modifiable risk factor for age-related macular degeneration (AMD). Smoking deception, or failing to self-report as a smoker, is a concern in studies of smoking-related disease.
Data from the 2005 to 2008 National Health and Nutrition Examination Survey were used to produce estimates of smoking deception among three ethnic groups within the United States population. Comparisons of self-reported rates of cigarette use, any nicotine product use, and serum cotinine levels were used to produce estimates of potential smoking deception among adults older than 40 years with any-level of AMD and those at risk of late-stage disease.
Any-level AMD was evident in 6.7 per cent (95% CI, 5.6-7.8 per cent) of this cohort. Excluding those with late-stage AMD, 9.7 per cent (95% CI, 8.3-11.0 per cent) were at risk of developing late-stage disease. Among individuals with any level of AMD, 5.4 per cent (95% CI = 2.1-8.6 per cent) were potential smoking deceivers. A similar rate was seen among those at risk of late-stage disease at 5.0 per cent (95% CI = 2.3 per cent to 7.6 per cent).
The findings suggest that as many as 450,000 adults in the USA who are at risk of late-stage AMD misclassify their smoking status.
Optom Vis Sci 2014. June 26. Epub ahead of print.
How do Müller cells work?
A paper in the prestigious journal Nature Communications has described the wavelength-dependent wave guiding properties of retinal Müller cells.
Retinal Müller cells separate between wavelengths to improve day vision with minimal effect on night vision.
Using computational modelling and experimental imaging methods, the authors found that Müller cells, which are the major type of glial cells in the retina, concentrate the green-red part of the visible spectrum onto cone photoreceptors, thereby allowing the blue-purple part to leak onto nearby rods.
Light propagation by Müller cells through the retina was reported to be an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision.
Nat Commun 2014; 5: 4319.
A novel ciprofloxacin-releasing silicone hydrogel contact lens
A novel silicone hydrogel contact lens designed for the extended release of ciprofloxacin may be beneficial to supplement or augment future treatments for microbial keratitis.
Model silicone hydrogel contact lens materials were synthesised using a molecular imprinting technique to augment ciprofloxacin-release kinetics. Various contact lens properties, including light transmission and surface wettability were determined, and the in vitro ciprofloxacin-release kinetics elucidated using fluorescence spectrophotometry. The synthesised materials were then evaluated for their ability to inhibit Pseudomonas aeruginosa growth, both in vitro and in a rabbit model of microbial keratitis.
The synthesised contact lenses were described to have material properties similar to those of commercial lens materials and released ciprofloxacin for more than eight hours. It was reported that in vivo, there was no statistically significant difference between the number of colony forming units (CFU) recovered from corneas treated with ciprofloxacin eye drops (0 CFU/cornea) and those treated with one of two modified contact lenses (mean: 4.3x10^3 CFU/cornea and 2.1x10^3 CFU/cornea).
Invest Ophthalmol Vis Sci 2014; Jul 15. Epub ahead of print.
Contact lens-assisted collagen cross-linking
A report in the Journal of Refractive Surgery describes a novel method of contact lens-assisted corneal collagen cross-linking (CXL) in eyes with corneal thicknesses that would typically preclude standard CXL.
Findings from 14 eyes with progressive keratoectasia and corneal thicknesses between 350-400 microns, following epithelial debridement, were included in the case series. After epithelial abrasion, iso-osmolar riboflavin 0.1 per cent in dextran was applied every three minutes for 30 minutes. An ultraviolet (UV) barrier-free soft contact lens soaked in iso-osmolar riboflavin 0.1 per cent for 30 minutes was placed on the cornea.
Once the minimum corneal thickness value was confirmed to be greater than 400 microns with the contact lens in situ, UVA irradiance was commenced; iso-osmolar 0.1 per cent riboflavin was also instilled in the pre-corneal and pre-contact lens region during the procedure. The mean depth of CXL stromal demarcation was 252.9 ± 40.8 µm (range: 208 to 360 µm), with no significant effect on endothelial cell count (p = 0.06).
The authors concluded that based on the corneal stromal demarcation line depth and the absence of adverse corneal outcomes, this technique appeared to be safe and effective in performing CXL in relatively thin corneas.
J Refract Surg 2014; 6: 366-372.
Girls benefit from cheese
A prospective study conducted in Australian adolescents has found that the consumption of dairy products, in particular cheese may have a beneficial effect on blood pressure (BP), particularly among girls.
The study aimed to prospectively assess whether dairy food consumption (milk, cheese, yoghurt) was associated with BP and retinal microvascular signs among adolescents. A total of 2353 12-year-olds and 1216 17-year-olds were examined; longitudinal analyses involved 888 subjects with complete baseline and follow-up data.
After multivariable adjustment, in girls each serve/day increase in total dairy intake was concurrently associated with 1.04 (p = 0.03) and 1.10 mmHg (p = 0.02) decreases in mean diastolic and arterial BP respectively; each serve/day increase in cheese intake over five years was concurrently related to 7.18 (p = 0.001), 5.28 (p = 0.002) and 5.79 mm Hg (p = 0.001) decrease in mean systolic, diastolic and arterial BP, respectively.
Nutr Metab Cardiovasc Dis 2014. June 14. Epub ahead of print.
Cataract surgery improves sleep for patients with IOLs
It has been found that a patient’s overall sleep quality and sleep latency is improved after cataract removal, irrespective of the type intraocular lens (IOL) that is implanted.
This study investigated the level of sleep disturbance in patients both before and after cataract surgery, and compared the effect of the implantation of UV-blocking or blue-filtering IOLs. Quality of sleep was quantified in 961 patients undergoing cataract surgery using a validated questionnaire.
Prior to cataract surgery, approximately half of patients reported poor sleep. Cataract removal was found to significantly improve overall sleep quality and sleep latency at one month post-operatively; this effect was sustained at 12 months.
It was concluded that these data demonstrate that implantation of blue-filtering IOLs do not have a negative impact upon the sleep-wake cycle, compared with UV-blocking IOLs.
Invest Ophthalmol Vis Sci 2014. June 26. Epub ahead of print.
Corneal sensitivity and tear function in neurodegenerative disease
Neurodegenerative diseases may be associated with reduced corneal sensitivity and abnormal tear function.
In this study, corneal sensitivity and tear function were measured in patients with different forms of neurodegenerative disease and findings were compared with age- and sex-matched controls.
Patients with Alzheimer’s disease (n = 20), multiple sclerosis (n = 20), Parkinson’s disease (n = 30), Friedreich’s ataxia (n = 10) and epilepsy (n = 21) were recruited from a tertiary neurology department. Corneal sensitivity was measured using the Cochet-Bonnet aesthesiometer. Tear function tests included tear-break-up-time (TBUT) and Schirmer test without anaesthesia.
Compared with control subjects, mean corneal sensitivity was significantly reduced in all of the pre-defined patient groups with neurodegenerative disease (p < 0.05), except for patients with Friedreich’s ataxia (p > 0.05). Mean TBUT was also significantly shorter in patients with Alzheimer’s disease and multiple sclerosis than controls (p < 0.05). Mean Schirmer test was relatively lower only in epilepsy patients (p < 0.05).
These findings suggest the presence of varying degrees of abnormality in corneal sensitivity and tear function in different forms of systemic neurodegenerative disease.
Curr Eye Res 2014; Jun 23: 1-6.