THE TRACHOMA STATUS AND BLINDNESS RATES OF SELECTED AREAS OF PAPUA NEW GUINEA IN 1979-80

A survey of 4 selected areas of Papua New Guinea was made during 1979-80 to establish the prevalence of trachoma and its complications, and blindness rates and causes, in those areas. Trachoma was found to be endemic in all the areas studied, but was of mild intensity and rarely caused visual deficit. It is suggested that the most practical step towards reducing the prevalence of trachoma in P.N.G., in the future, is not by a mass treatment campaign, but by basic education in simple hygiene. An overall blindness rate of 0.50% was found in this survey, indicating that blindness is not a big problem in P.N.G. today. However there is still a need tor improved Primary Eye Health Care, the training of national ophthalmologists, and provision for one institution for the training of the blind in P N G.     

RETINOBLASTOMA IN THE ANTERIOR CHAMBER OF THE EYE

An uncommon presentation of retinoblastoma in an eleven-year-old boy is discussed. There was no family history of retinoblastoma and the child had never complained of a sore eye. He was not aware that he could not see out of his right eye.     

THE USE OF ULTRASONOGRAPHY IN DETERMINING THE AMOUNT OF EXTRAOCULAR MUSCLE SURGERY IN STRABISMUS

In twenty strabismus patients using ultrasonography a measurement was taken from the apex of the orbit through the centre of rotation of the eye to the front of the eye along the oculomotor axis which is at an angle of approximately 10° to the anteroposterior axis of the eye. From this and from the diameter of the eye average values were derived for the distance from the equator of the medial rectus insertion of 6.27 mm (range 3. 96–8. 92 mm) the lateral rectus insertion 8. 77 mm, the length of the medial rectus 35.32 mm (range 32. 40–40.25 mm) and the lateral rectus 37.82 mm (range 34, 79–42. 75 mm). There are sources of error in these measurements but they are probably not great, though corneal diameter and muscle positions should be checked at operation. In addition a recession/muscle length ratio may be calculated and it is probably wise not to exceed a ratio of 0. 20 for the medial rectus and 0.25 for the lateral rectus with similar resection muscle length ratios suggested. The variability of the distance of the muscle insertions from the equator is greater than the muscle lengths and it seems important not to recess beyond the equator while alteration of muscle length may be less important This suggests maximal recession of the medial rectus may vary from 4 up to almost 9 mm and from 6.5 to almost 11.5 mm for the lateral rectus. The value of making these measurements pre-operatively seems obvious and the considerable variation is the amount of squint surgery is stressed, particularly for muscle recessions.     

Corneal endothelial response to induced myopia in the chicken

Purpose : To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. Methods : Lid suture was performed on one eye of 1‐day‐old cockerels. Five chickens were killed at 1 week, and four chickens killed at each of 3 weeks, 6 weeks, and 10 weeks postnatal. The endothelial morphology was obtained by flat mounting the endothelial surface and the subsequent digitisation. Comparisons were undertaken between the control unsutured eye and the lid‐sutured eye endothelium, and between the central endothelial areas compared to the peripheral endothelial areas in both the myopic and the normal corneas. Calculation of the contribution to the endothelial change by hypertrophy and mitosis were calculated using Bahn’s formula. Results : Total endothelial surface area increased significantly over time in the myopic model compared to control eyes but the mean cell area of endothelial cells remained the same for both the enlarged myopic endothelial surface area and in the normal controls. Sampling from the central and the peripheral corneal endothelial surface also disclosed no difference. The mean cell area did increase steadily with age but was the same for both normal and myopic corneas. Conclusions : It would appear that there are equal contributions from hypertrophy and mitosis in the myopic group and the normal corneal group with a slightly increasing trend towards mitotic activity in the myopic corneal endothelial layer.     

Differential diagnosis of corneal oedema assisted by in vivo confocal microscopy

The purpose of this study was to demonstrate microstructural differences between clinically similar, but aetiologically different, cases of corneal oedema in four subjects. In vivo confocal microscopy highlighted oedema of the basal epithelium, prominent nerve–keratocyte interactions, and typical ‘epithelialization’ of the endothelium in a case of iridocorneal endothelial syndrome; however, a similar microstructural appearance was observed in a case of presumed herpetic disciform keratitis. The latter diagnosis was subsequently revised on this basis. Confocal examination of Fuchs’ endothelial dystrophy demonstrated oedema of the basal epithelium, prominent wing cells, anterior stromal alterations, fibrosis of Descemet’s membrane and a typical ‘strawberry’ appearance of the endothelium. In contrast, in vivo microstructural examination of bilateral keratoconus with hydrops confirmed oedema mainly involving the epithelium and anterior stroma. In vivo confocal microscopy allows the clinician to observe the living cornea at a microstructural level and to better diagnose and differentiate borderline or unusual cases of corneal oedema.     

The failed probing

The management of failed probing for congenital nasolacrimal duct obstruction is given by a panel of authors. Treatment options examined are repeat probing, inferior turbinate infracture, closed lacrimal intubation and dacryocystorhinostomy. There is considerable variation as to the timing of these interventional techniques.     

SURFBOARD-RELATED OCULAR INJURIES

Three cases of ocular trauma caused by surfboards are reported. The severe nature of the injuries is discussed and the prevalence of this type of injury is reviewed.     

'Hot' corneal grafts—a long-term study

Abstract
A six-year follow-up of nine of 13 eyes treated by therapeutic keratoplasty for suppurative keratitis is described. One of the thirteen cases died three years after surgery_-and three were lost to follow-up. Two of the nine refused reoperation after early graft failure. Of the remaining seven, three had retained good functional visual acuity. Three of the penetrating keratoplasties required regrafting two to four years later, when conditions were less critical. Long-term results indicate that therapeutic keratoplasty may be an alternative modality for the management of suppurative keratitis with satisfactory long-term optical results.     

INFECTION AFTER RETINAL DETACHMENT SURGERY

In 250 consecutive retinal detachment operations performed by the author, there were 14 cases (56%) of infection of the scleral buckle The commonest infecting organism was Staphylococcus aureus.
The surgery in these infected cases took longer than average, and utilized more than the usual amount of silicone sponge, a higher proportion were reoperations After an average follow-up of 22 months, only six of the 14 had vision of 6/36 or better and of these, two had persisting inferior traction detachments.
On the basis of this study and others, the preferred management of infected scleral buckles is to remove the sponge as soon as the diagnosis is made The risk of redetachment is a lesser evil than the sequelae of prolonged inflammation which include traction retinal detachment, massive perirebnal proliferabon, and premacular fibrosis.