J E A Somner

Node retrieval in axillary lymph node dissections: recommendations for minimum numbers to be confident about node negative status

Aims: To determine the minimum number of lymph nodes needed in an axillary lymph node dissection (ALND) specimen to be confident that the axilla is free from metastases. Methods: The Edinburgh Breast Unit selects patients with large and high grade tumours for ALND; 609 consecutive ALNDs performed between October 1999 and December 2002 were reviewed. Full data about the underlying invasive breast cancer were available for 520 patients. Data were collected regarding number of positive nodes and total number of nodes collected, tumour size and grade, and presence of lymphovascular invasion. Results: Axillary node metastases were seen in 64% of patients. The mean number of positive nodes found was 3.56, with a mean of 17.9 nodes collected. The highest proportion of patients with lymph node metastases were in the group with 16–20 nodes recovered/specimen (68%); specimens with >20 nodes recovered did not have a higher rate of nodal involvement. There was a significant difference between the proportion of metastasis positive specimens in those with 1–15 nodes recovered (58.5%) and those with 16 or more recovered (69.1%). A linear association test showed a direct correlation between the number of nodes collected and presence of node metastasis (p = 0.0005). Conclusions: Although there is no minimum number of nodes that should be recovered in an ALND specimen, 16 nodes should be regarded as a target to ensure a high level of confidence that the nodes are negative. Node positivity in an ALND specimen appears to obey the law of diminishing returns.

Corneal thickness at high altitude

Purpose: The eye, like other organs, is affected by the hypobaric hypoxia of high altitude. Corneal swelling is known to occur under hypoxic conditions at sea level, for instance when wearing contact lenses. The aim of this study was to measure central corneal thickness (CCT) in lowlanders ascending to altitude. Methods: The Apex 2 medical research expedition provided the opportunity to measure CCT in 63 healthy lowlanders. The subjects arrived in La Paz, Bolivia (3700 m), where they spent 4 days acclimatizing before being driven over 2 hours to the Cosmic Physics Laboratory at Chacaltaya (5200 m), where they stayed for 7 days. CCT was measured in the early afternoon by using ultrasound pachymetry on the first, third, and seventh day at 5200 m and before and after the expedition at sea level. Results: Mean CCT increased significantly from 543 μm at sea level to 561 μm on the first day at 5200 m (P < 0.001). This continued to increase to 563 μm on the third day and 571 μm on the seventh day but returned to 541 μm after descent to sea level. Conclusions: This study showed that altitude caused a significant increase in CCT in a large group of healthy lowlanders with normal corneas. This finding confirms the results of previous studies and is likely to be caused by endothelial dysfunction causing stromal swelling. This could potentially cause visual problems for high-altitude mountaineers among whom refractive surgery is popular.

The Eye at Altitude

High altitude retinopathy (HAR) was first described in 1969 as engorgement of retinal veins with occasional papilloedema and vitreous hemorrhage. Since then various studies have attempted to define the incidence, etiology and significance of this phenomenon, usually with small numbers of subjects. Recently studies on relatively large groups of subjects in Nepal, Bolivia and Tibet have confirmed that the retinal vasculature becomes engorged and tortuous in all lowlanders ascending above 2500m. Sometimes this leads to hemorrhages, cotton wool spots and papilloedema, which is the pathological state better known as high altitude retinopathy. These studies have also shown a significant change in both corneal thickness and intraocular pressure at altitude. The retinal blood vessels are the only directly observable vascular system in the human body and also supply some of the most oxygen-demanding tissue, the photoreceptors of the retina. New techniques are being applied in both hypobaric chamber and field expeditions to observe changes in retinal function during conditions of hypobaric hypoxia. This work allows better advice to be given to lowlanders traveling to altitude either if they have pre-existing ocular conditions or if they suffer from visual problems whilst at altitude. This especially applies to the effect of altitude on refractive eye surgery and results of recent studies will be discussed so that physicians can advise their patients using the latest evidence. Retinal hypoxia at sea level accounts for the developed worlds largest cause of blindness, diabetic retinopathy. The investigation of retinal response to hypobaric hypoxia in healthy subjects may open new avenues for treatment of this debilitating disease.

Genotypic Influences on Severity of Exudative Age-Related Macular Degeneration

PURPOSE Major genetic risk factors have recently been identified for age-related macular degeneration (AMD), including the ARMS2/LOC387715 and CFH at-risk polymorphisms. The study was conducted to establish correlations between the AMD genotype and both the phenotype and severity of AMD. METHODS In a prospective cohort of 1216 AMD patients, four genotypic homozygous groups were identified (n = 264): double homozygous for wild-type alleles (group 1, n = 49), homozygous for the at-risk allele of ARMS2/LOC387715 only (group 2, n = 57), homozygous for the at-risk allele of CFH only (group 3, n = 106), and double homozygous for both at-risk alleles (group 4, n = 52). The phenotypic classification of exudative AMD was based on fluorescein angiography. RESULTS Mean age at presentation was significantly lower in group 4 than in group 1 (P < 0.014). Patients in group 4 presented more often with bilateral CNV and fibrovascular scars than did patients in group 1 (P < 0.001 and < 0.0031 respectively) and with significantly lower visual acuity (VA) in the first affected eye than did patients in group 1 (P < 0.02). Patients in group 2 presented with worse VA than did patients in group 3 (P < 0.003). Classic CNV was more commonly associated with the at-risk allele of the ARMS2/LOC387715 locus than with the at-risk allele of the CFH gene (P < 0.026). CONCLUSIONS This study demonstrates an association between the at-risk allele of the ARMS2/LOC387715 locus and classic CNV, fibrovascular lesions, and poor VA. Individuals double homozygous for both at-risk alleles had a higher risk of being affected with a severe form of AMD at an earlier age.

The carbon footprint of cataract surgery.

BackgroundClimate change is predicted to be one of the largest global health threats of the 21st century. Health care itself is a large contributor to carbon emissions. Determining the carbon footprint of specific health care activities such as cataract surgery allows the assessment of associated emissions and identifies opportunities for reduction.AimTo assess the carbon footprint of a cataract pathway in a British teaching hospital.MethodsThis was a component analysis study for one patient having first eye cataract surgery in the University Hospital of Wales, Cardiff. Activity data was collected from three sectors, building and energy use, travel and procurement. Published emissions factors were applied to this data to provide figures in carbon dioxide equivalents (CO2eq).ResultsThe carbon footprint for one cataract operation was 181.8 kg CO2eq. On the basis that 2230 patients were treated for cataracts during 2011 in Cardiff, this has an associated carbon footprint of 405.4 tonnes CO2eq. Building and energy use was estimated to account for 36.1% of overall emissions, travel 10.1% and procurement 53.8%, with medical equipment accounting for the most emissions at 32.6%.ConclusionsThis is the first published carbon footprint of cataract surgery and acts as a benchmark for other studies as well as identifying areas for emissions reduction. Within the procurement sector, dialogue with industry is important to reduce the overall carbon footprint. Sustainability should be considered when cataract pathways are designed as there is potential for reduction in all sectors with the possible side effects of saving costs and improving patient care.

Ophthalmology carbon footprint: Something to be considered?

recurrent pterygial cells than on primary ones. Our small prospective interventional study documented favorable outcomes of the use of topical MMC in the management of acutely recurring pterygium. It effectively halted progression and led to regression of the growth, avoiding the need for repeat surgical excision. However, larger clinical trials are warranted to evaluate the long-term safety and efficacy of this treatment.

Intractable diplopia: a new indication for corneal tattooing

A 54-year-old woman was referred with intractable diplopia. Six years previously, she had been involved in a road traffic accident which resulted in a partial right third nerve palsy, a sixth nerve palsy and a blow-out fracture …

Inadvertent injection of intravitreal air during intravitreal Lucentis injection for wet age-related macular degeneration: an undescribed complication

Inadvertent injection of intravitreal air during intravitreal Lucentis injection for wet age-related macular degeneration: an undescribed complication

Eyes, economics and the environment: should green issues drive changes in ophthalmic care?: Yes

Eyes, economics and the environment: should green issues drive changes in ophthalmic care? –Yes

The precautionary principle: what is the risk of reusing disposable drops in routine ophthalmology consultations and what are the costs of reducing this risk to zero?

BackgroundInstilling eye drops is a ubiquitous procedure in eye clinics. This audit aimed to assess the risk of contamination of disposable droppers and to quantify the financial and waste implications of reducing this risk to zero by using disposable droppers only once.MethodsA total of 100 disposable Minims were used to place one drop in each eye of 70 patients. The dropper tip was then cultured for aerobic and anaerobic microbes.ResultsCoagulase-negative staphylococcus was cultured from five samples. The contamination rate per drop application was 2.5%. The risk of cross-contamination with coagulase-negative staphylococcus would be between 1 : 400 and 1 : 80 if the bottle was reused once or six times. Reducing this risk to zero costs between £2.75 and £4.6 million per annum and generates between 6.85 and 11.42 more tonnes of paper waste and between 12.69 and 21.15 more tonnes of plastic waste than a strategy that reuses the disposable dropper.ConclusionReducing the risk of dropper contamination and subsequent cross infection has financial and environmental costs. As exposure to coagulase-negative staphylococcus is not necessarily associated with infection, it would be useful to decide acceptable risk levels for a given cost to maximise both cost-effectiveness and patient safety.