Australian and New Zealand journal of ophthalmology最新文献

Some patients may experience respiratory side effects on betaxolol in spite of the greater safety which is claimed for this ocular hypotensive drug compared with timolol. Six of 29 patients using betaxolol complained of wheeze or respiratory distress and five of these patients were rechallenged with betaxolol and a placebo in a double-masked clinical study, respiratory function being measured before and after each medication according to the American Thoracic Society guidelines. No patient showed any change in respiratory function either with betaxolol or the placebo. The findings further support the safety of betaxolol even in patients with respiratory disease, though some caution should be observed.

An operation for complete third nerve paralysis involving lateral rectus muscle transplantation to the medial side of the globe as a basic procedure is described. An inferior rectus muscle recession plus resection of an apparent completely paralysed medial rectus was subsequently performed at a second stage operation. The results appeared to be an improvement on previous surgery, particularly in terms of ocular motility, with almost full adduction of the operated eye being achieved. This adduction movement occurred as part of a normal conjugate movement of the two eyes, and the question arises as to the responsible muscles, with some evidence to suggest that relearned action of the transplanted lateral rectus muscle may be implicated. Finally, a Fasanella-Servat procedure as a third stage operation appeared to be adequate to correct the ptosis.

A simple system has been developed for the clinical grading of the presence and severity of lens opacities. The densities of nuclear opacities as seen on clinical slit-lamp examination are graded in comparison with a set of standard photographs. The extent of cortical opacities seen on retroillumination is estimated in terms of segments involved. The dimensions of posterior subcapsular opacities are measured using the slit beam. Inter- and intraobserver trials were conducted with three observers. Twenty subjects were selected to provide a range of lens opacities. Weighted Kappa statistics for intraobserver agreement for these three types of opacities range between 0.58 and 1.00 and for interobserver agreement between 0.41 and 0.71. This clinical grading system shows good reproducibility and compares well with the grading of lens opacities in photographs. It should prove to be of considerable use in clinical and epidemiological studies of cataract.

Forty-three patients with congenital nystagmus who underwent surgery in the Ocular Motility Clinic at The Royal Victorian Eye and Ear Hospital, Melbourne, are analysed to assess the effect of different surgical approaches on the abnormal head posture and binocular visual performance. There were 38 patients with a horizontal head turn, and five with a vertical abnormal head posture. In those undergoing horizontal nystagmus surgery the different surgical procedures have been classified as: Anderson procedure, which involves large bilateral augmented recessions only; Kestenbaum and augmented Kestenbaum bilateral recess/resect surgery in which the recess:resect ratio is less than 1; and a modified Anderson-Kestenbaum procedure with the emphasis on large recessions, so that the bilateral recess/resect ratio is greater than 1. In this series the augmented recessions of the Anderson and Anderson-Kestenbaum procedures appeared to produce a more favourable result of improved binocular vision. The five patients with vertical abnormal head posture with nystagmus had various surgical procedures with very encouraging results, both in terms of reduction of the abnormal head posture and an even greater improvement of binocular vision than with the horizontal cases. The surgical techniques in these cases are presented and discussed.

The results of analyses of 1218 consecutive corneal transplants performed in a single centre reveal that the most important prognostic factors for corneal allograft survival are recipient corneal vascularisation, graft diameter, HLA-A and B matching especially for high risk patients, organ culture storage of donor corneas prior to transplantation and donor age.

Computer models of strabismus have been available for about ten years. Such models are computer programs which perform a set of calculations based on an interpretation of the oculomotor system as a system of two spheres each with six adjustable springs. The effects of pathology and surgery can be simulated by altering the parameters of the springs. However, such models have not yet met with wide practical acceptance. One reason for this lack of interest is that previous investigators have neglected to apply strabismus models to concomitant strabismus. In this paper the application of a strabismus model to concomitant strabismus is demonstrated and data are generated which should be clinically useful. Another reason for lack of acceptance of computer models results from the expectation that they may be unreliable because of biological variability. The model developed here is tested for its sensitivity to a wide range of biological variations and proves to be very robust. Therefore, information on concomitant squint surgery given by the model should be applicable to most patients.

Neurovisual adaptations to subnormal vision in children are of practical importance and need to be remembered in the management of children with low vision. The physiological adaptations discussed include shortening the focal distance, abnormal head positions, compensatory head movements, and ocular motor search strategies. In addition the concept of neural plasticity, particularly in respect to the ability of the extrageniculate striaete system to assume primary visual function in cortically damaged children is discussed.

Symptoms that persist after operations for angle-closure glaucoma arise from different causes. In the presence of open peripheral iridectomies miotics may be beneficial or may close angles; wide pupil dilatation by phenylephrine used to diminish posterior synechiae may close angles; cycloplegic mydriatics will close some angles and open others. Unexpected bizarre reactions to eye drops may occur. Persistent chronic glaucoma will be more common after laser iridotomy than after correctly assessed filtering operations. The importance of gonioscopy in diagnosis and management is emphasised.