Associate Professor Mark Roth
BSc(Pharm) BAppSc(Optom) PGCertOcTher NECO FAAO
Warm facecloth offers cold comfort against MGD
An ex vivo study to evaluate the heat retention properties of a warm facecloth versus commercially-available masks has found that the new products are superior to the old facecloth.
Meibomian gland dysfunction (MGD) appears to be the most common cause of evaporative dry eye. Eyelid warming masks slowly transfer heat between 40° and 45° C to the inner meibomian glands, in an attempt to melt or soften the stagnant meibum.
Five eyelid-warming masks (MGDRx EyeBag, EyeDoctor, Bruder, Tranquileyes, Thera Pearl) were heated following manufacturers’ instructions. Heat retention was assessed at one-minute intervals for 12 minutes on a non-conductive surface. A facecloth warmed with hot tap water was used as comparison.
All masks reached above 40° C within the first two minutes after heating and remained so for five minutes, with the exception of the facecloth, which lasted only three minutes and quickly degraded to 30° C within 10 minutes.
The Bruder and Tranquileyes products reached > 50° C, after heating and the Bruder goggles maintained > 50° C for nearly six minutes. The MGDRx EyeBag and TheraPearl have the most stable heat retention (in targeted ranges) between two and nine minutes.
The study authors concluded that although the heat-retention profiles are different for commercially-available eyelid warming masks, the time-honoured facecloth is poor at retaining the desired heat over a 5-10 minute interval.
Cont Lens Ant Eye 2015; Feb 27. (Epub ahead of print)
Seasonal variations of dry eye
Researchers have formally quantified a clear seasonal pattern of dry eye, and have shown that a majority of the dry eye cases occur in winter and spring.
All patients seen in a US veteran eye clinic from July 5 2006, to July 4 2011, were included in this retrospective analysis. To further evaluate the link between allergens and seasons, the study authors obtained information from www.pollen.com, which provides a monthly allergy index, based on pollen concentrations, for various locations throughout the USA.
In total, 17.4 per cent of veterans were diagnosed with dry eye. When looking at the distribution of cases, researchers observed a clear seasonal pattern. Specifically, the prevalence of dry eye was highest in April, which corresponded with pollen counts in the USA.
In a multivariable analysis considering meteorological conditions, season and allergy index on dry eye prevalence, seasonality showed the strongest association with dry eye, with dry eye prevalence during peak seasons (winter–spring) being 3.7 per cent higher compared with summer–fall.
‘Our study supports the general clinical impression that dry eye has a seasonal pattern and suggests that different mechanisms may underlie dry eye in winter vs spring months,’ the authors concluded.
The authors went on to point out the importance of this distinction, because the treatment approaches to dry eye may differ based on whether an allergy is a component of disease.
Understanding which indoor and outdoor environmental conditions, across different seasons, most closely align with dry eye can open new treatment algorithms that include environmental manipulation, such as air filters and humidifiers for indoor use or goggles for outdoor use.
Ophthalmology 2015; 122: 8: 1727-1729. doi: 10.1016
Sjögren’s syndrome may be underdiagnosed in men
Although primary Sjögren’s syndrome (SS) is typically considered a disease of middle-aged women, a recent study has found that it may be underdiagnosed, and consequentially more severe, in men.
In a retrospective cohort study, a total of 163 consecutive primary Sjögren’s syndrome (SS) patients were evaluated between January 2007 and March 2013 to measure the frequency of extraglandular ocular and systemic manifestations and serologic results in men compared to women.
Fourteen of the 163 primary Sjögren’s syndrome patients (nine per cent) were men. On initial presentation, men were a decade older (61 vs 50 years, p < 0.01) and less likely than women to have a prior diagnosis of Sjögren’s syndrome (43 per cent vs 65 per cent, p = 0.09).
A majority of men reported dry eye on presentation (92 per cent), albeit less chronic compared to women (5.9 vs 10.8 years, p = 0.07). Men were more likely to present with serious ocular complications than women (43 per cent vs 11 per cent, p = 0.001). Extra glandular systemic complications of Sjögren’s syndrome, for example: vasculitis, interstitial nephritis, were also more common in men (64 per cent vs 40 per cent, p = 0.07). Men were more likely to be negative for anti-SSA/Ro, anti-SSB/La, and antinuclear antibodies than women (36 per cent men vs 11 per cent women, p = 0.01).
Researchers concluded that men with primary Sjögren’s syndrome have a higher frequency of serious ocular and systemic manifestations.
The researchers proposed that there should be a lower threshold to test for Sjögren’s syndrome in men with dry eye.
AJO 2015; 160: 3: 447–452.
Corneal topography in children with vernal keratoconjunctivitis
A high prevalence of keratoconus-like topography was observed in patients with vernal keratoconjunctivitis (VKC).
A study was conducted in Kathmandu, Nepal, to determine corneal topographic characteristics of children with VKC. Corneal topographic indices in VKC subjects were then compared with those of normal subjects.
In the hospital-based comparative study, 115 consecutive subjects with VKC and 102 age and sex matched normal subjects were selected for videokeratography with the NIDEK ophthalmic operating system.
Other assessments included visual acuity testing with LogMAR chart, slitlamp biomicroscopy, dilated fundus examination, measurement of central corneal thickness and intraocular pressure. Topographic indices were analysed and compared using unpaired t-test among different groups. Sensitivity and specificity was estimated by the ROC curve.
Among the 115 subjects with VKC, males comprised 86 subjects (66.1 per cent of the total) and the mean age of presentation was 10.9 (SD 4.9) years with mixed VKC in 56.5 per cent. Keratoconus-like topography was present in 13 subjects (11.3 per cent). The keratoconus predictive index (sensitivity 92.3 per cent, specificity 98.5 per cent), the opposite sectoral index (sensitivity 84.6 per cent; specificity 93.2 per cent) and the differential sectoral index (sensitivity 92.3 per cent; specificity 90.8 per cent) were found to be significantly associated with VKC subjects having keratoconus-like topography.
Cont Lens Ant Eye 2015; June 9 (Epub ahead of print)