Factors affecting accuracy in the Developmental Eye Movement Test measurement for Cantonese‐speaking children

Background: This study aims to determine the factors affecting the accuracy in the Developmental Eye Movement (DEM) test measurement for Cantonese‐speaking children. Method: The voices of 10 Cantonese‐speaking children (aged between six and eight years) undertaking the vertical test (40 numbers) of the DEM test were recorded on a digital audio recorder. These voice clips were assessed by an experienced examiner to give the DEM test times. The examiner repeated the measurement five times for each voice clip and completed all 10 voice clips from the 10 children. The average of a single measurement, the mean of two, the mean of three and the mean of five repeated measurements were then compared. Five experienced and five inexperienced examiners of the DEM test were asked to record the results from five Cantonese‐speaking children by listening to the playback of prerecorded audio clips. The deviation of the results from the preset values between the two groups was compared. Results: There is no difference between the single measurement and those obtained by mean of two, three, four or five. Both experienced and inexperienced examiners obtained a higher deviation from the preset values in the adjusted compared with the non‐adjusted times in both vertical and horizontal times. Experienced examiners measured the vertical times and adjusted vertical times significantly closer to the preset values than the inexperienced examiners (paired t‐test, p < 0.05). Conclusion: The DEM test needs to be measured only once for an accurate time measurement. Inaccurate assessment of ‘reading errors’ in the DEM test can increase the inaccuracy of the adjusted times. It is suggested that an audio recording of the test be made to allow reassessment of reading errors. Experience in using the DEM test yields a more accurate DEM measurement as errors are detected more easily.     

How do Australian optometrists manage work‐related physical discomfort?

Background: Work‐related physical discomfort exists within the optometric profession. It is not well understood how optometrists manage this issue in their workplaces. Method: An online questionnaire was sent by e‐mail to approximately 1,700 Australian optometrists. Participants were asked if they experienced work‐related discomfort in any of eight nominated body regions. If so, they were asked to describe specific work tasks, which contribute to their work‐related discomfort, and strategies they have adopted to minimise their discomfort. These data were subject to qualitative and quantitative analyses. Results: There was a 25 per cent response rate and 416 optometrists participated in the questionnaire. Work‐related physical discomfort was reported by 339 respondents (81 per cent), most commonly with the use of the phoropter (n = 144, 35 per cent) and slitlamp (n = 94, 23 per cent). Males were more likely to report lower back discomfort with phoropter use (Chi‐squared, p < 0.01) and ophthalmoscopy (Chi‐squared, p < 0.01). To minimise discomfort, optometrists 41 years and older were more likely to report that they adjust their posture (Chi‐squared, p < 0.03) and females were more likely to report that they alter their work schedule (Chi‐squared, p < 0.05). A recurrent theme expressed by participants was an inability to make changes to improve their comfort due to room and equipment design, poorly maintained equipment, non‐supply of suitable equipment or furniture and inherent difficulties within optometric tasks. Conclusion: There is a need for all optometrists to have skills to evaluate their own personal risk of discomfort in the consultation room. Owners and managers of optometric practices also need greater awareness of the importance of room and equipment design and maintenance on work‐related discomfort. This has implications for the well‐being of optometrists, for their productivity and for compliance with health and safety legislation.     

Cytotoxicity and effects on metabolism of contact lens care solutions on human corneal epithelium cells

Purpose: The aim was to determine the cytotoxic effects of three multipurpose solutions (MPS) on human corneal epithelial cells (HCEC) and to assess the metabolic rates of recovering cells at different levels of cell membrane damage. Method: The effects of one to 15 minutes exposure to multipurpose solutions containing polyquaternium‐1 (MPS‐A), polyaminopropyl biguanide (MPS‐B) and polyhexanide (MPS‐C) on HCEC were determined. Recovery rates at different levels of cell membrane damage were assessed after re‐culture for two hours at 37°C. Cell viability and membrane integrity were assessed using Annexin V‐FITC/7‐AAD staining and flow cytometry. Effects of concentrations of 10 to 40 per cent multipurpose solutions on the metabolic rate of recovering HCEC were assessed using a Vybrant MTT cell proliferation assay kit. Results: The highest percentage of late necrotic cells resulted after exposure to MPS‐A compared with other solutions and the control (p < 0.001). The percentages of early necrotic cells after 10 and 15 minutes of soaking in MPS‐B were significantly higher than the control and other multipurpose solutions (p < 0.001). Although MPS‐C exposure also resulted in statistically significant higher percentages of early necrotic cells than the control (p < 0.005), these differences were small. No recovery was noted when HCEC treated with multipurpose solutions were re‐cultured, with numbers of dead cells in MPS‐B‐treated cultures increasing fourfold. The MTT assay showed significant dose‐response decreases of 500 nm absorbance for all MPS‐treated cells. In 40 per cent MPS‐A‐treated HCEC, lack of activity indicated the cells were non‐viable. Conclusions: Multipurpose solutions induced varying levels of irreversible tissue sensitivity reactions, with MPS‐A showing the greatest effects. The solutions damaged cell integrity and reduced metabolic rates suggesting delayed healing ability. The formulations of multipurpose solutions need to balance antimicrobial effectiveness with low cytotoxicity, which might not be currently possible to achieve. In light of our results, we suggest that contact lens wearers should be advised to rinse the soaked lenses with saline before lens insertion.     

To prescribe or not to prescribe? Guidelines for spectacle prescribing in infants and children

This paper discusses the considerations for prescribing a refractive correction in infants and children up to and including school age, with reference to the current literature. The focus is on children who do not have other disorders, for example, binocular vision anomalies, such as strabismus, significant heterophoria or convergence excess. However, refractive amblyogenic factors are discussed, as is prescribing for refractive amblyopia. Based on this discussion, guidelines are proposed, which indicate when to prescribe spectacles and what amount of refractive error should be corrected. It may be argued that these are premature because there are many questions that remain unanswered and we do not have the quality of evidence that we would like; the clinician, however, must make decisions on whether and what to prescribe when examining a child. These guidelines are to aid clinicians in their current clinical decision making.     

Clinical outcomes following the dispensing of ready‐made and recycled spectacles: A systematic literature review

Uncorrected refractive error is the leading cause of global visual impairment. Given resource constraints in developing countries, the gold standard method of refractive error correction, custom‐made spectacles, is unlikely to be available for some time. Therefore, ready‐made and recycled spectacles are in wide use in the developing world. To ensure that refractive error interventions are successful, it is important that only appropriate modes of refractive error correction are used. As a basis for policy development, a systematic literature review was conducted of interventional studies analysing visual function, patient satisfaction and continued use outcomes of ready‐made and recycled spectacles dispensed to individuals in developing countries with refractive errors or presbyopia. PubMed and CINAHL were searched by MESH terms and keywords related to ready‐made and recycled spectacle interventions, yielding 185 non‐duplicated papers. After applying exclusion criteria, eight papers describing seven studies of clinical outcomes of dispensing ready‐made spectacles were retained for analysis. The two randomised controlled trials and five non‐experimental studies suggest that ready‐made spectacles can provide sufficient visual function for a large portion of the world's population with refractive error, including those with astigmatism and/or anisometropia. The follow‐up period for many of the studies was too short to confidently comment on patient satisfaction and continued‐use outcomes. No studies were found that met inclusion criteria and discussed recycled spectacles. The literature also notes concerns about quality and cost effectiveness of recycled spectacles, as well as their tendency to increase developing countries' reliance on outside sources of help. In light of the findings, the dispensing of ready‐made spectacles should be favoured over the dispensing of recycled spectacles in developing countries.     

A case of amblyopia with contralateral optic nerve hypoplasia

We describe an unusual case of unilateral optic nerve hypoplasia (ONH) in a patient with contralateral anisometropic/strabismic amblyopia. A seven‐year‐old boy presented with visual acuities of 6/12 R and 6/18 L and eccentric fixation in the left eye. Cycloplegic retinoscopy was R +1.50/‐0.50 × 180 and L +5.25 DS. Funduscopy revealed optic nerve hypoplasia of the right eye. The patient fixated with his better‐seeing right eye, despite the optic nerve hypoplasia. His reduced vision may be attributed to optic nerve hypoplasia in the right eye and amblyopia in the left. Although optic nerve hypoplasia can occur with ipsilateral amblyopia, we believe this is the first reported case of unilateral optic nerve hypoplasia in the fellow eye of an amblyopic patient.     

Synthetic corneal inlays

This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant team from 1991 to 2007. The development of a synthetic polymer of perfluoropolyether (PFPE), meeting essential physical and biological requirements, for use as a corneal inlay is presented. Each inlay was placed in a corneal flap created with a microkeratome and monitored over a two‐year period in a rabbit model. The results indicate that the PFPE implant shows excellent biocompatibility and biostability. As a result, a Phase 1 clinical trial is being conducted. Three years post‐implantation, the PFPE inlays are exhibiting continued excellent biocompatibility. Corneal inlays made from PFPE are biocompatible with corneal tissue in the long term and offer a safe and biologically‐acceptable alternative to other forms of refractive surgery.