Iris melanomas: are they more frequent in New Zealand?
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Adult↗
Biomedical subjects
R Clemett
Publications and source records attributed to R Clemett.
Results of screening low-birth-weight infants for retinopathy of prematurity.
Retinopathy of prematurity (ROP) continues to be an important cause of potentially preventable blindness worldwide. The pattern of visual impairment from ROP in some middle-income countries--high rates affecting larger and more mature infants--resembles that seen in more developed countries two decades ago and has been called a "third epidemic" of the disease. Expert bodies in the United Kingdom and the United States have recently issued new guidelines for screening for ROP that utilize both birth weight and gestational age criteria. Studies in both countries suggest these criteria might be further revised to decrease time spent on screening without missing any significant disease. Population-based follow-up studies of extremely preterm infants suggest that although more preterm infants are surviving, with adequate screening and treatment, rates of blindness from ROP may be declining. Further information on the longer-term impact of ROP comes from a number of studies and particularly the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) study. The risk of both myopia and strabismus is increased with any and each higher stage of ROP. Evidence is emerging that laser therapy for threshold disease may be associated with better visual outcome than cryotherapy, although complications following the former remain a concern. The fight against ROP may be enhanced by new information on the pathogenesis, including possible genetic predisposition and the role of vascular endothelial growth factor.
Blindness↗
Primary choroidal malignant melanoma occurring in a New Zealand Maori.
PURPOSE/METHOD: A case of a 28-year-old Maori with an aggressive primary choroidal malignant melanoma is presented. RESULTS/CONCLUSION: Melanoma and particularly intra-ocular melanoma is very rare in pigmented races. This is the first reported case in the Maori.
Adult↗
An anatomical study of retinal arteriovenous crossings and their role in the pathogenesis of retinal branch vein occlusions.
To elucidate the anatomical features which predispose artery over vein (AV) crossings to be the preferential sites for retinal branch vein occlusions (RBVO), 11 AV and six vein over artery (VA) crossings in 12 eyes from non-hypertensive donors who were aged 35 to 82 years, were studied by light and electron microscopy. At AV crossings the veins were often observed to abruptly alter direction to pass under the artery. Here focal stratification of the vein basement membrane opposite the point of contact with the artery was seen. A focal reduction in the vein lumen occurred at three of 11 AV crossings. In contrast, deviation of the vein, focal basement membrane stratification or focal narrowing was not seen at VA crossings. Both types of crossings had a common adventitial sheath when each vessel was of large calibre. This study demonstrated anatomical features which predispose AV crossings to be the preferential site for venous occlusion.
Adult↗
An unusual ciliary body tumour: a haemangioblastoma.
A 23-year-old woman who presented with blurred vision in her right eye from increasing astigmatism had a vascular ciliary body tumour. After slow growth was documented over a 15-month period the tumour was excised with an iridocyclectomy. Microscopically the tumour consisted of sheets of large polygonal cells with round nuclei and foamy cytoplasm, separated by numerous capillaries, findings consistent with a diagnosis of a haemangioblastoma. Haemangioblastomas occur in the retina in von Hippel's disease and this occurrence in the ciliary body is a rare event. Investigation of the patient with a CT of the head and an abdominal ultrasound revealed no systemic lesions suggestive of systemic angiomatosis or von Hippel-Lindau disease.
Adult↗
Vitelliform dystrophy: long-term observations on New Zealand pedigrees.
Long-term observations on 29 patients from four pedigrees with vitelliform dystrophy (Best's disease) are described. The majority of patients were examined at yearly intervals and had a mean follow-up of 7.4 years. For analysis, eyes were staged according to Mohler and Fine's classification. Although vitelliform dystrophy exhibited considerable polymorphism in the study group 'recognisable stages', such as egg-yolk cysts, scrambled cysts or pseudohypopyon, were present in 48% of eyes at the initial examination. Egg-yolk cysts and pseudohypopyons were found to be the most evanescent of stages lasting on average 2.0 and 2.4 years respectively. Evolution of lesions did not necessarily follow a regular progression through the later stages of the vitelliform classification. Several unusual features such as recurrent pseudohypopyon, apparent regeneration of retinal pigment epithelium, exudative retinal detachments and development of stellate pigment figures were observed during the study. The majority of patients retained 6/12 or better visual acuity until the fourth decade when vision deteriorated. Correlations between changes in visual acuity and staging of the fundal lesions were made. Similarities between the group of patients reported, and a comparative group from overseas' have been discussed.
Adolescent↗
Corneal rust removal by electric drill. Clinical trial by comparison with manual removal.
The dental burr rotated by an electric drill is the quickest, safest, and most precise form of treatment for corneal rust rings. It enables complete removal of the corneal rust at a single treatment and leaves a smooth crater that is no larger than the original rust ring. Pain relief is more rapid after electric drill removal; this is probably related to the complete removal of the rust. Epithelial and stromal healing are marginally faster than after manual removal and the patients' duration of attendance is less. The ideal drill is a slim straight instrument, which rotates dental burrs and is operated by a light finger pressure. A brake which stops drill rotation on lifting the finger is a useful safety feature.
Cornea↗