Aims-To compare stereophotographic and monophotographic optic disc assessments made using a digital optic disc stereo camera. Methods-Stereo digital optic disc photographs of 150 selected patients who had presented to a glaucoma clinic were assessed by two masked observers on separate occasions using (1) the stereophotographs and a stereoviewer, (2) a single image from the same stereopair. Results were analysed for both right and left eyes separately. 95% tolerance limits for change (TC) and intraclass correlation coeYcients (ICC) were calculated and a multivariate analysis using a general linear model for repeated measures was performed. Conclusions-This study using a digital stereo camera indicates that there may be little benefit of stereoscopic imaging over monoscopic imaging despite demonstrating small but inconsistent diVerences between both observers and methods. (Br J Ophthalmol 2001;85:1347-1351 The detection of early or progressive glaucomatous optic disc changes is essential in the optimum management of glaucoma patients. Despite the plethora of new technologies the accepted "gold standard" for optic disc assessment remains stereoscopic optic disc photography. Results-1-4 However, measurements rely on a subjective evaluation by the clinician and are subject to poor interobserver agreement. 5-10The Discam optic disc camera (Marcher Enterprises Ltd, Hereford) obtains digital monochromatic sequential stereophotographic images of the optic disc and the allied software allows the computation of a number of optic disc parameters. In a previous study, the intraobserver and interobserver repeatability of optic disc measurements was shown to compare favourably with ophthalmoscopic and stereophotographic methods of assessment of the optic disc.11 However, stereoscopic versus monoscopic assessments of the images were not performed.The aims of this study were to determine whether there were significant diVerences in intraobserver and interobserver repeatability of the computed optic disc parameters using monophotographic and stereophotographic images to determine the margins of the optic disc and optic cup. Materials and methodsStereophotographic digital images of patients presenting to a glaucoma clinic were acquired by two experienced operators following pharmacological mydriasis. The detailed method has been previously described. 11 The quality of the images were assessed by observer 2 (MC), on the basis of contrast, clarity, stereoscopic appearance, illumination, and excessive movement between the image pair. As this study did not aim to determine the clinical usefulness of the Discam, but purely to compare two methods of assessment, only high quality images were used for analysis in order to maximise any diVerences. Exclusion criteria were poor illumination of the disc, poor quality image, lens opacity, poor stereoimage (large shift on the screen between images of stereo pair) and optic discs of anomalous configuration (those which were tilted, colobomatous, or myopic). A total of 201 images (from a ...

We recommend that all referrals for cataract should confirm a detrimental effect on lifestyle and the patient's willingness for surgery, in addition to confirming cataract as the main cause of visual loss.

Background-In the 4 year period (1988-91) there were nine cases of bacterial keratitis in five critically ill patients on an intensive care unit ('unit A'), all except one due to Pseudomonas aeruginosa. Many of these patients had serious ocular complications requiring surgery and all surviving patients were left with significant visual deficits. One further case of keratitis due to P aeruginosa occurred on unit A in April 1993. The problem of keratitis in ventilated patients is not unique to this unit as a further four cases in three patients from additional units in this area have been treated. Methods-Predisposing factors in unit A were established through subsequent investigations. It was found, in particular, that all the ocular infections were preceded by colonisation of the respiratory tract with the pathogenic organism. Recommendations concerning eye care and tracheal suctioning were adopted by unit A in 1991. Results-In the subsequent 4 years (1991-5), the frequency of isolation of pseudomonas from the respiratory tract per patient treated in unit A remained relatively high at 3.8% (153/4032). However, the conjunctival pseudomonas isolation rate has decreased significantly (p <0.001) from 0.8% (19/2430) to 0.05% (2/4032). Conclusions-Ventilated patients may be at risk from inoculation of pathogens into the eyes. The principal risk factor for bacterial keratitis in this series was corneal exposure secondary to conjunctival chemosis or lid damage. The adoption of simple preventative measures on unit A had a significant impact on the incidence of eye infections due to pseudomonas, despite the high proportion of patients whose respiratory tracts were colonised with the same organism. There is a need for additional research into the most eVective method of eye care for ventilated patients in order to reduce the frequency of this avoidable condition.