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Longitudinal studies of visual and cognitive development in young children with Down's syndrome
172
Ophthal.
Physiol.
Opt.
1997
17: No 2
there was a significant increase in the calculated fixed negative charge values obtained. At physiological concentration of NaCl (150 mM), the fixed negative charge was calculated to be 39.98 + 1.05 mEq I-‘. For NaAcetate, NaThiocyanate and NaHCO, at 150mM the fixed negative charge was calculated to be 38.6420.51, 43.62kO.51 and 41.98 f 0.65 mEq I-’ respectively (n = 10, f SEM). Conclusion: The degree of anion binding in bovine cornea1 stroma varies from anion to anion and is dependent on the external bathing solution concentration. At 150mM, the binding series from this study is NaThiocyanate > NaHCO, > NaCl > NaAcetate.
Accuracy of a calibrated retinoscope K. L. Smythe Manchester Royal Eye Hospital, Oxford Road, Manchester, Ml3 9WH, UK Aim: It is not always possible in clinical practice to use a trial frame. We have therefore attempted to compare the accuracy of cylinder axis determination using standard retinoscopy versus a calibrated retinoscope. Methods: We have designed a scale, fitted to a standard retinoscope, which indicates the axis of cylinder. A single experienced retinoscopist determined, in a blind manner, the axis of cylinder using the new calibrated retinoscope and a traditional instrument with a trial frame distant from the eye. Retinoscopy was performed on a model eye using each retinoscope first in a random fashion. The axis of cylinder was set randomly at 5” intervals between 5” and 180”, retinoscopy being performed using each instrument three times at each interval. Results: On x2 statistical analysis we found the calibrated retinoscope was significantly more accurate to within 5” of the true cylinder axis. Conclusion: The accuracy of the cylinder determination, when refracting without using a trial frame, can be significantly improved to within 5°C of the true axis when using a calibrated retinoscope.
Reproducibility of topographic measurements of the optic nerve head with the Heidelberg Retina Tomograph using separate and imported contour lines E. J. Roff’,‘, S. L. Hosking’, D. A. Barnes’ and J. M. Gibson2 ‘Department of Vision Sciences, Aston University; and 2Birmingham Heartlands Hospital, Birmingham Purpose: To investigate whether topographical measurements of the optic nerve head are more reproducible when the contour line is redrawn for each image as opposed to imported using the Heidelberg Retina Tomograph (HRT). Introduction: Optic nerve head topography can be measured in viva using Confocal Scanning Laser Ophthalmoscopes such as the HRT. Image analysis requires that the area of the optic disc is defined by subjectively drawing a contour line around Elschnig’s ring. The HRT software can export this contour line between images for a subject, or the contour line can be redrawn. Method: Ten eyes of ten normal volunteers (40-60 years) were analysed with the HRT. Seven 10” images of the optic disc were taken by one observer for each randomly selected eye. Focus and scan depth settings were kept constant. All available stereometric parameters were analysed using three methods: (1) with a separately drawn contour line for each individual image, (2) with a contour line imported from the first image into subsequent images of the series, (3) by repeatedly redrawing the contour line for a single image from each eye. All contour lines were drawn by one observer. Mean co-efficients of variation were calculated for each parameter for the three methods. Results: The mean co-efficient of variation for the parameters ranged from 1.7-23.4% (method l), O-20% (method 2) and 1.6-13.4% (method 3). Conclusion: These results show that redrawn contour lines increase variability. Topographical measurements of the optic nerve head are more reproducible if the contour line is imported across subsequent images rather than redrawn for each individual image.
Longitudinal studies of visual and cognitive development in young children with Down’s syndrome M. Gregg’, J. M. Woodhouse’, M. Parker’, V. H. Pakeman’, W. I. Fraser2, P. Sastry3 and S. Lobo3 ‘Department of Optometry and Vision Sciences, University of Wales, Cardiff, PO Box 905, Cardiff CFl 3XF, UK; 2Welsh Centre of Learning Disability, Card@ 3Community Health Unit, Cardiff As part of a long-term study of visual and cognitive development in children with Down’s syndrome, we are monitoring visual functions, including visual acuity, accommodation, refractive error, as well as scores on Bayley Scales of Infant Development in a cohort of 64 children throughout South and West Wales. Cross-sectional data, presented at a previous meeting, suggest a remarkable similarity between acuity and cognitive scores, in that both progress rapidly in the early months, and undergo a sudden rate change at the age of 2 years. We now have a sufficient longitudinal data to re-examine the progress of these two functions. Results for 12 children, each seen four times at similar ages, were analysed. Those children whose visual acuity falls outside the normal range at later ages, also show significantly lower cognitive scores, when compared to the children with normal visual acuity.
Non-compliance in contact lens wear Bridget E. Claydon’, Nathan Efron’ and Craig Woods2 ‘Department of Optometry and Vision Sciences, University of Wales, Cardiff, Redwood Building, King Edward VII Avenue, Cardiff CFl 3XF, UK; and 2Department of Optometry and Vision Sciences, University of Manchester Institute of Science and Technology, PO Box 88, Manchester M60 lQD, UK Non-compliance in the contact lens field has been widely documented and discussed. The major areas of non-compliance in contact lens wear have been highlighted as the lack of hand and lens case hygiene, the overwearing of contact lenses, the poor attendance of patients at aftercare appointments and the inadequate use of care and maintenance systems. Education is one of the factors thought to influence compliance. A prospective, randomized, controlled and double masked study was performed to assess the effect of a ‘compliance enhancement strategy’ on levels of compliance among contact lens wearers over 12 months. Eighty experienced contact lens patients were randomly allocated to two experimental groups. A standard level of contact lens instruction was applied to the first group, and in addition extra education was applied to patients in the second group. Patients were given free supplies of ReNu multipurpose solution and Medalist 38 soft contact lenses (Bausch & Lomb, Rochester, New York). Compliance levels were assessed at a 12.month aftercare appointment by demonstration and questionnaire. The results indicate that the additional education had a significant effect on the compliance levels of the patients to whom it was applied. The population of contact lens wearers were generally very compliant and the contact lenses and care regimen were clinically successful. In this paper the results for the whole study population are compared to those reported in previous compliance studies. The results are found to be similar in many areas and suggest that practitioners should be encouraged to review the compliant behaviour of their contact lens patients at every aftercare appointment, paying particular attention to the areas of frequent non-compliance highlighted.
Absence of Naf/K’/2CIcotransporter activity in cornea1 endothelial cell plasma membrane vesicles Jason R. Lane, Chris G. Wigham and Stuart A. Hodson Department of Optometry and Vision Sciences, University of Wales, Cardiff, PO Box 905, Cardiff CFl 3XF, UK
Ophthal.
Physiol.
Opt.
1997
17: No 2
there was a significant increase in the calculated fixed negative charge values obtained. At physiological concentration of NaCl (150 mM), the fixed negative charge was calculated to be 39.98 + 1.05 mEq I-‘. For NaAcetate, NaThiocyanate and NaHCO, at 150mM the fixed negative charge was calculated to be 38.6420.51, 43.62kO.51 and 41.98 f 0.65 mEq I-’ respectively (n = 10, f SEM). Conclusion: The degree of anion binding in bovine cornea1 stroma varies from anion to anion and is dependent on the external bathing solution concentration. At 150mM, the binding series from this study is NaThiocyanate > NaHCO, > NaCl > NaAcetate.
Accuracy of a calibrated retinoscope K. L. Smythe Manchester Royal Eye Hospital, Oxford Road, Manchester, Ml3 9WH, UK Aim: It is not always possible in clinical practice to use a trial frame. We have therefore attempted to compare the accuracy of cylinder axis determination using standard retinoscopy versus a calibrated retinoscope. Methods: We have designed a scale, fitted to a standard retinoscope, which indicates the axis of cylinder. A single experienced retinoscopist determined, in a blind manner, the axis of cylinder using the new calibrated retinoscope and a traditional instrument with a trial frame distant from the eye. Retinoscopy was performed on a model eye using each retinoscope first in a random fashion. The axis of cylinder was set randomly at 5” intervals between 5” and 180”, retinoscopy being performed using each instrument three times at each interval. Results: On x2 statistical analysis we found the calibrated retinoscope was significantly more accurate to within 5” of the true cylinder axis. Conclusion: The accuracy of the cylinder determination, when refracting without using a trial frame, can be significantly improved to within 5°C of the true axis when using a calibrated retinoscope.
Reproducibility of topographic measurements of the optic nerve head with the Heidelberg Retina Tomograph using separate and imported contour lines E. J. Roff’,‘, S. L. Hosking’, D. A. Barnes’ and J. M. Gibson2 ‘Department of Vision Sciences, Aston University; and 2Birmingham Heartlands Hospital, Birmingham Purpose: To investigate whether topographical measurements of the optic nerve head are more reproducible when the contour line is redrawn for each image as opposed to imported using the Heidelberg Retina Tomograph (HRT). Introduction: Optic nerve head topography can be measured in viva using Confocal Scanning Laser Ophthalmoscopes such as the HRT. Image analysis requires that the area of the optic disc is defined by subjectively drawing a contour line around Elschnig’s ring. The HRT software can export this contour line between images for a subject, or the contour line can be redrawn. Method: Ten eyes of ten normal volunteers (40-60 years) were analysed with the HRT. Seven 10” images of the optic disc were taken by one observer for each randomly selected eye. Focus and scan depth settings were kept constant. All available stereometric parameters were analysed using three methods: (1) with a separately drawn contour line for each individual image, (2) with a contour line imported from the first image into subsequent images of the series, (3) by repeatedly redrawing the contour line for a single image from each eye. All contour lines were drawn by one observer. Mean co-efficients of variation were calculated for each parameter for the three methods. Results: The mean co-efficient of variation for the parameters ranged from 1.7-23.4% (method l), O-20% (method 2) and 1.6-13.4% (method 3). Conclusion: These results show that redrawn contour lines increase variability. Topographical measurements of the optic nerve head are more reproducible if the contour line is imported across subsequent images rather than redrawn for each individual image.
Longitudinal studies of visual and cognitive development in young children with Down’s syndrome M. Gregg’, J. M. Woodhouse’, M. Parker’, V. H. Pakeman’, W. I. Fraser2, P. Sastry3 and S. Lobo3 ‘Department of Optometry and Vision Sciences, University of Wales, Cardiff, PO Box 905, Cardiff CFl 3XF, UK; 2Welsh Centre of Learning Disability, Card@ 3Community Health Unit, Cardiff As part of a long-term study of visual and cognitive development in children with Down’s syndrome, we are monitoring visual functions, including visual acuity, accommodation, refractive error, as well as scores on Bayley Scales of Infant Development in a cohort of 64 children throughout South and West Wales. Cross-sectional data, presented at a previous meeting, suggest a remarkable similarity between acuity and cognitive scores, in that both progress rapidly in the early months, and undergo a sudden rate change at the age of 2 years. We now have a sufficient longitudinal data to re-examine the progress of these two functions. Results for 12 children, each seen four times at similar ages, were analysed. Those children whose visual acuity falls outside the normal range at later ages, also show significantly lower cognitive scores, when compared to the children with normal visual acuity.
Non-compliance in contact lens wear Bridget E. Claydon’, Nathan Efron’ and Craig Woods2 ‘Department of Optometry and Vision Sciences, University of Wales, Cardiff, Redwood Building, King Edward VII Avenue, Cardiff CFl 3XF, UK; and 2Department of Optometry and Vision Sciences, University of Manchester Institute of Science and Technology, PO Box 88, Manchester M60 lQD, UK Non-compliance in the contact lens field has been widely documented and discussed. The major areas of non-compliance in contact lens wear have been highlighted as the lack of hand and lens case hygiene, the overwearing of contact lenses, the poor attendance of patients at aftercare appointments and the inadequate use of care and maintenance systems. Education is one of the factors thought to influence compliance. A prospective, randomized, controlled and double masked study was performed to assess the effect of a ‘compliance enhancement strategy’ on levels of compliance among contact lens wearers over 12 months. Eighty experienced contact lens patients were randomly allocated to two experimental groups. A standard level of contact lens instruction was applied to the first group, and in addition extra education was applied to patients in the second group. Patients were given free supplies of ReNu multipurpose solution and Medalist 38 soft contact lenses (Bausch & Lomb, Rochester, New York). Compliance levels were assessed at a 12.month aftercare appointment by demonstration and questionnaire. The results indicate that the additional education had a significant effect on the compliance levels of the patients to whom it was applied. The population of contact lens wearers were generally very compliant and the contact lenses and care regimen were clinically successful. In this paper the results for the whole study population are compared to those reported in previous compliance studies. The results are found to be similar in many areas and suggest that practitioners should be encouraged to review the compliant behaviour of their contact lens patients at every aftercare appointment, paying particular attention to the areas of frequent non-compliance highlighted.
Absence of Naf/K’/2CIcotransporter activity in cornea1 endothelial cell plasma membrane vesicles Jason R. Lane, Chris G. Wigham and Stuart A. Hodson Department of Optometry and Vision Sciences, University of Wales, Cardiff, PO Box 905, Cardiff CFl 3XF, UK