Structural impact of arrested foveal development in children born extremely preterm without ROP at 6.5 years of age.

OBJECTIVES: To characterize changes of foveal topography and microstructure of persisting foveal immaturity at 6.5 years of age in children born extremely preterm without retinopathy of prematurity (EPT-NoROP). METHODS: Images from previous optical coherence tomography examinations of 37 EPT-NoROP and 92 control eyes were selected from a regional cohort of the EXPRESS (Extremely Preterm Infants in Sweden) study. Thickness of ganglion cell + inner plexiform layer (GCL+), outer nuclear layer (ONL), retinal thickness (RT) at the foveal centre (FC), foveal depth (FD) and RT at the foveal rim were evaluated. RESULTS: Layer thickness of GCL+, ONL and RT was increased at FC in the EPT-NoROP group. More than two-thirds had thickness values above the control limit (control mean +2 SD) at FC (GCL + 68%, ONL 76%, and RT 68%), and 50% had reduced FD compared to controls. All parameters showed a high correlation within the EPT-NoROP group, whereas no or weaker correlation was seen in control eyes. The EPT-NoROP sub-groups, divided based on the control limit, did not differ in terms of associated factors such as gestational age, birth weight, visual acuity, and refraction. CONCLUSIONS: Extreme prematurity without impact of ROP is associated with increased GCL + , ONL, and RT thickness at FC as well as reduced FD compared to full-term controls at age 6.5. This indicates that prematurity per se may have a profound effect on foveal anatomical maturation during the first months after birth. Our results suggest RT at FC to be a simple and useful measure of foveal anatomical immaturity.

Structural consequences of arrested foveal development in preterms with persisting signs of immaturity.

PURPOSE: To evaluate the impact of structural changes in a limited sample of adult preterms with foveal immaturity from optical coherence tomography (OCT) B-scan images and to estimate layer displacement and changes in areal and volume magnification within the inner fovea. SUBJECTS AND METHODS: Layer thickness was measured in conventional and directional OCT scans from eight preterms with different degrees of foveal immaturity (24-33 weeks of gestation, 22-33 years of age) and five controls (20-33 years of age). We obtained reflectivity profiles of the outer plexiform layer (OPL) and manual segmentation data of the inner nuclear layer (INL) and the combined ganglion cell layer (GCL) and inner plexiform layer (IPL) at specified eccentricities from 300 to 900 µm. Displacement of cumulative thickness curves of preterms compared with that of the controls was used to estimate retardation of layer displacement. Changes in areal magnification and layer thickness were used to construct a structural model of redistribution within the fovea of preterms. RESULTS: Retardation of centrifugal layer displacement of OPL and all inner retinal layers (IRL) was marked in both preterm groups with foveal immaturity, whereas retardation was marginal in the preterm group without clinical signs of immaturity. Retarded displacement within the IRL and OPL had a major impact on available space within the central fovea. CONCLUSIONS: A marked retardation of displacement was demonstrated for all IRL within the immature fovea of preterms with decreased areal and volume magnification and reduced space available for synaptic communication coupled to the degree of immaturity.

Arrested Foveal Development in Preterm Eyes: Thickening of the Outer Nuclear Layer and Structural Redistribution Within the Fovea.

Purpose: The aim of this study was to define landmarks to better characterize foveal microstructure in normal subjects and in preterms with or without signs of immaturity, and to report on thickness changes of outer foveal layers following analysis of optical coherence tomography (OCT) B-scan images. Methods: Selected eyes from eight young adults with a history of prematurity (24-33 weeks of gestation) and five controls were imaged using conventional and directional OCT. Retinal layer thickness analysis was performed at selected temporal eccentricities defined by the individual distance between two landmarks for each case, the foveal center and the foveal rim. Results: The use of a foveal center and foveal rim landmark transformation enabled comparisons of interindividual B-scans at corresponding landmark positions in both controls and preterms. We found a 20% shorter foveal center to foveal rim distance in preterms with an immature fovea than in controls. Reflectometric and manual segmentation measurements showed increased thickness of inner retinal layers and photoreceptor cell body and outer plexiform layers centrally, but no observable change of photoreceptor inner and outer segment thickness. Conclusions: Our landmark-based analysis of OCT images using reflectometry and manual segmentation provides complementary findings in comparisons of normal and immature foveal structures. We show a central thickness increase in the outer nuclear layer, outer plexiform layer, and postreceptor layers in preterms with signs of arrested foveal development. We found no indication of abnormal photoreceptor inner or outer segment development in preterms.

A methodological approach for evaluation of foveal immaturity after extremely preterm birth.

PURPOSE: To characterize typical microanatomical alterations of immaturity in the fovea, that remain into childhood, after extremely preterm birth before 27 weeks gestational age (GA) and to suggest a clinical methodological evaluation tool. METHODS: Subjects were consecutively recruited at age 6.5 years and organized in four groups (10 subjects in each): Group A (full-term), Group B (GA 25-27 weeks) without retinopathy of prematurity (ROP), Group B* (GA 25-27 weeks) and Group C (GA 23-24 weeks) both with ROP stage 3. Foveal microanatomy was studied using a grading system of OCT-scans. RESULTS: Prematurely born children (including Group B, B* and C) had significantly reduced foveal depth (mean difference -53 µm, p < 0.001), thicker inner retinal layer (mean difference 21.6, p = 0.005) and thicker outer nuclear layer (mean difference 23.5, p < 0.001) than controls. Foveal depth and inner retinal layer thickness were significantly correlated to GA (p = 0.003 and p = 0.017 respectively) within the preterm group. Foveal depth increased with 14.1 µm per week between GA 23 and 27. The three hyper reflective bands of the outer segments as well as a central protuberance of inner and outer segment layers were present in all children. CONCLUSION: Previous studies have revealed signs of immaturity affecting most retinal layers at time of birth in prematurely born children. The present study adds information to which extent these signs of underdevelopment remains to later in life. The applied method showed that premature birth before GA 27 weeks commonly leads to characteristic anatomical alterations of the foveal anatomy expressed as reduced foveal depth and incomplete extrusion of the inner retinal layers. Although deviations of the outer nuclear layers can be seen in the most extremely preterm born children, the outer part of the fovea generally develops well, independent of prematurity. The single most important determinant for the degree of foveal maturation seems to be GA.

Reliability of a standardized test in Swedish for evaluation of reading performance in healthy eyes. Interchart and test-retest analyses.

PURPOSE: The purpose of our study was to establish a practical and quick test for assessing reading performance and to statistically analyse interchart and test-retest reliability of a new standardized Swedish reading chart system consisting of three charts constructed according to the principles available in the literature. METHODS: Twenty-four subjects with healthy eyes, mean age 65 ± 10 years, were tested binocularly and the reading performance evaluated as reading acuity, critical print size and maximum reading speed. The test charts all consist of 12 short text sentences with a print size ranging from 0.9 to -0.2 logMAR in approximate steps of 0.1 logMAR. Two testing sessions, in two different groups (C1 and C2), were under strict control of luminance and lighting environment. Reading performance tests with chart T1, T2 and T3 were used for evaluation of interchart reliability and test data from a second session 1 month or more apart for the test-retest analysis. RESULTS: The testing of reading performance in adult observers with short sentences of continuous text was quick and practical. The agreement between the tests obtained with the three different test charts was high both within the same test session and at retest. CONCLUSION: This new Swedish variant of a standardized reading system based on short sentences and logarithmic progression of print size provides reliable measurements of reading performance and preliminary norms in an age group around 65 years. The reading test with three independent reading charts can be useful for clinical studies of reading ability before and after treatment.

Noninvasive imaging of human foveal capillary network using dual-conjugate adaptive optics.

PURPOSE: To demonstrate noninvasive imaging of human foveal capillary networks with a high-resolution, wide-field, dual-conjugate adaptive optics (DCAO) imaging instrument. METHODS: The foveal capillary networks of five healthy subjects with no previous history of ocular or neurologic disease or surgery were imaged with a novel high-resolution, wide-field DCAO instrument. The foveal avascular zone (FAZ) in each image was defined using a manual procedure. An automated algorithm based on publicly available and custom-written software was used to identify vessels and extract morphologic FAZ and vessel parameters. Capillary densities were calculated in two annular regions of interest (ROIs) outside the FAZ (500 µm and 750 µm outer radius from the foveal center) and in the superior, inferior, temporal, and nasal quadrants within the two ROIs. RESULTS: Mean FAZ area was 0.302 ± 0.100 mm(2), and mean capillary density (length/area) in the inner ROI was 38.0 ± 4.0 mm(-1) and 36.4 ± 4.0 mm(-1) in the outer ROI. The difference in ROI capillary density was not significant. There was no significant difference in quadrant capillary density within the two ROIs or between quadrants irrespective of ROI. CONCLUSIONS: The authors have demonstrated a technique for noninvasive imaging and semiautomated detection and analysis of foveal capillaries. In comparison with other studies, their method yielded lower capillary densities than histology but similar results to the current clinical gold standard, fluorescein angiography. The increased field of view of the DCAO instrument opens up new possibilities for high-resolution noninvasive clinical imaging of foveal capillaries.

The decline in visual acuity in elderly people with healthy eyes or eyes with early age-related maculopathy in two Scandinavian population samples.

PURPOSE: This study aimed to analyse the decline in visual acuity (VA) during normal ageing in two Scandinavian population samples of subjects aged ≥ 70 years and to study the age-specific decline in VA in eyes with early age-related maculopathy (ARM). METHODS: We carried out a cross-sectional analysis of data pertaining to VA in the better eye in one population sample from Oulu (OU), Finland (aged 70-82 years) and a second population sample from Gothenburg (GG), Sweden (aged 82 or 88 years). The change in VA with age was evaluated in healthy eyes (OU, n = 119; GG, n = 40) and in eyes with early ARM (OU-ARM, n = 22; GG-ARM, n = 114) using linear regression or logistic regression. The results were compared with those of previous reports. RESULTS: Our population samples showed a significant decrease with age in VA in healthy eyes in subjects aged ≥ 44 years using both statistical models. Comparisons with previous reports demonstrated a homogeneity in the decline in VA with age. On average, 0.3 logMAR are lost from middle age up to 88 years, presumably as a result of physiological ageing. In early ARM, the rate of age-specific decline in VA more than doubled and the prevalence of VA < 0.5 markedly increased. CONCLUSIONS: Visual acuity in healthy eyes declines with age from middle age onwards. The decrease in VA possibly accelerates in subjects aged > 70 years, although no significant evidence for this was found. An age-specific decline in VA is shown in eyes with early ARM. These results are important for the evaluation of age-specific treatment results.

Stability of visual outcome from 7 years in children treated surgically for bilateral dense congenital cataracts before 37 weeks of age.

PURPOSE: To study the long-term visual outcome and the age at which final visual acuity can be predicted in a population sample of children treated surgically for bilateral dense congenital cataract before 37 weeks of age. In addition, we assessed the influence of associated risk factors and compared the visual development of these aphakic children with presumably blocked visual input before early surgery to that of normal children in Sweden. METHODS: The 18 patients included were followed for at least 10 years postoperatively. The median age at last visit was 15.5 years (range 10-18). The best-corrected visual acuity (BCVA) was tested monocularly with a logarithmically scaled letter acuity test from 4 years of age to late teens. Other registered postoperative data were presence of manifest nystagmus, strabismus and complications. RESULTS: The BCVA of the better-seeing eye reached a plateau at 7 years of age. Age at surgery of 80 days or less characterized the majority of cases with a logMAR ≤ 0.3 with a threshold effect between 80 and 130 days of age. Compared to normal children in Sweden, the long-term visual outcome showed a deficit of 0.5-0.6 logMAR. CONCLUSION: In spite of optimized care and surgery before 9 months, the BCVA was subnormal in our population compared to healthy children. The long-term visual outcome can be predicted at 7 years of age. Screening with early detection followed by surgery before the end of the third month is important to decrease the risk of marked acuity loss.

Longitudinal change in aphakic refraction after early surgery for congenital cataract.

PURPOSE: To characterize the longitudinal changes of refraction in aphakic eyes after early surgery for congenital cataract and to evaluate longitudinally measured aphakic refraction (individual vs group mean) as a noninvasive indicator of postoperative disturbances in ocular development. METHODS: Records of children who had cataract surgery during their first year of life between 1980 and 1995 were obtained from a prospective, population-based study of congenital cataract. Only children with regular follow-up were included. Postoperative aphakic refraction was calculated at the corneal plane. Data were obtained up to 36 months of age. RESULTS: The study included 28 children (49 eyes) who underwent surgery at a median age of 2.8 months (range, 0-9 months). The decrease of aphakic refraction at the corneal plane followed a logarithmic trend (R(2) = 0.95). A total of 36 eyes followed this pattern, with no growth in 8 eyes and an increased growth rate in 1 eye with uncontrolled glaucoma and 4 eyes of 2 children with Down syndrome. CONCLUSIONS: Most aphakic eyes follow a predictable, logarithmic change in refraction in the first 3 years of life, Longitudinal monitoring of refraction may prove to be a useful, noninvasive screening method for early detection of disturbances in aphakic eye growth.

Resolution visual fields in children surgically treated for bilateral congenital cataract.

PURPOSE: To evaluate visual acuity (best corrected visual acuity) and peripheral sensitivity, measured by high-pass resolution (HRP) visual fields, in children surgically treated for congenital cataract. METHODS: Acuity and peripheral sensitivity were recorded from 16 children, aged 10 to 15 years, either surgically treated for bilateral dense cataract before the age of 4.6 months (n = 10) or surgically treated for bilateral partial cataract at ages 4 to 139 months (n = 6). Data from 22 healthy children, mean age 11 years, served as control. RESULTS: The children with cataract had significantly (P < 0.0001) lower decimal acuity in their better eye (median, 0.55; range, 0.1-1.3) than did the control subjects (median, 1.2; range, 1.0-1.6). Five children were visually impaired according to the World Health Organization's definition (i.e., acuity in the better eye <0.3). The children with previous dense bilateral cataract showed significantly lower peripheral sensitivity than did the control subjects (P = 0.004). Significant correlations were observed between acuity and visual field parameters. CONCLUSIONS: Dense cataract, even when surgically treated before the age of 4.6 months, causes persistent impairment of spatial vision, both in the fovea and the visual field. The effect on the visual field is less pronounced than that on visual acuity. This finding has to be taken into account when evaluating visual field results in, for example, the diagnosis of glaucoma, a frequent complication after cataract surgery in early infancy.

A randomized controlled trial of a health-promotion programme and its effect on ADL dependence and self-reported health problems for the elderly visually impaired.

BACKGROUND: Ageing with visual impairment is associated with a high degree of disability whereby age-related macular degeneration in particular causes dependence in activities of daily living (ADL) even at an early stage. AIMS: To compare an activity-based, health-promotion programme with an individual programme, targeting the elderly with age-related macular degeneration concerning the effect on the development of dependence in ADL, general health, and self-reported health problems. METHODS: A randomized controlled study with a 28-month follow-up. A total of 229 persons were randomized to the study and 131 (57%) were followed up (individual intervention n=69, health-promotion programme n=62) at 28-month. RESULTS: The health-promotion group maintained their ADL level despite a significant decrease in visual acuity, while the individual intervention group increased its dependence in ADL. General health systematically dropped to a lower level in both groups, but participants from the health-promotion group reported fewer health problems. There were significantly fewer reports of tiredness and dizziness among the health-promotion participants. CONCLUSION: The health-promotion programme seems to have slowed down the disablement process among elderly with decreased vision by enabling them to maintain their ADL level and by reducing self-reported health problems for at least 28 months following intervention.

Strabismus might be a risk factor for amblyopia recurrence.

BACKGROUND: Previous reports have suggested that one-fourth of amblyopic subjects present with recurrence of amblyopia even after successful primary treatment. Risk factors for amblyopia recurrence are insufficiently studied, but therapy weaning has recently been suggested as a method for reducing the risk of recurrence. METHODS: In the second phase of a prospective study examining the results of treatment for amblyopia, all 35 children with successful primary amblyopia treatment were put on maintenance therapy. Maintenance therapy consisted of low-intensity patching, atropine, or blurring filter, and all children were regularly examined up to at least 8 years of age. Mean age at start of maintenance therapy was 4.3 years (range, 2-7 years). RESULTS: Of the 35 cases with successful primary treatment, 6 cases deteriorated >or=0.2 logMAR, which was considered recurrence of amblyopia. Two of these cases had a second recurrence. Notably, all six subjects presenting with recurrence had microstrabismus. This finding was just outside statistical significance at the 95% confidence level (p = 0.06), but the sample size was small. All but one of the recurrences appeared within 6 months after successful primary treatment. Age at successful primary treatment or initial interocular difference of visual acuity did not affect the risk of recurrence. CONCLUSIONS: Recurrence of amblyopia occurred in 17% of patients despite maintenance therapy and was associated with microstrabismus. The majority of recurrences occurred within the first 6 months after primary treatment.

The relation between resolution measurements and numbers of retinal ganglion cells in the same human subjects.

Limiting factors of resolution have previously only been investigated by using resolution data and retinal ganglion cell spacing data from different individuals. We report on our unique opportunity to study the intra-individual relationship in three human subjects between retinal ganglion cell separations and resolution thresholds, measured with high-pass resolution perimetry. Our data show that resolution is directly proportional to half the midget population, in accordance with the hypothesis that a dichotomous midget ON/OFF population mediates resolution.

Quality of light and quality of life--the effect of lighting adaptation among people with low vision.

PURPOSE: The study has investigated the effect of lighting on the daily activities (ADL) of the visually impaired in their homes by comparison before and after light adjustments were made in the kitchen, hall and bathroom. It has also investigated the additional effects on the quality of life after providing task lighting in the living room. METHOD: A total of 56 people were consecutively recruited from those receiving lighting adaptation help by the Low Vision Clinic in Göteborg. Ten persons did not complete the study. After medical examinations, lighting standards and psychosocial factors were charted. After lighting improvements were carried out in the kitchen, hall and bathroom, the subjects were randomly divided into two groups, an intervention and a comparison group. The task lighting in the living room was also improved for those included in the intervention group. Follow-up interviews to determine ADL and quality of life were performed 6 months after lighting adaptation. RESULTS: A marked effect on quality of life of the lighting in the living room was found for the intervention group. The effect on ADL of the basic lighting adaptation in kitchen, hall and bathroom for both groups was significant for tasks carried out on the working surface in the kitchen. Other activities in the kitchen and in the bathroom tended to improve but changes were not significant. CONCLUSION: The results confirm that it is possible to increase quality of life by improving the lighting conditions.

Ocular changes, risk markers for eye disorders and effects of cataract surgery in elderly people: a study of an urban Swedish population followed from 70 to 97 years of age.

AIMS: To investigate the prevalence of and potential risk factors for ocular disorders and the effects of timing of cataract surgery from age 70-97 years. POPULATION: A representative population sample taken from within the Gerontological and Geriatric Population Studies (H 70) in Gothenburg, Sweden (n = 958). All subjects underwent eye examinations at age 70 years in 1971 and subsequently at ages 82, 88, 95 and 97 years. All inhabitants of Gothenburg aged 95 and 97 years were invited to participate in the study. RESULTS: Decreased vision (visual acuity < or = 0.5) was found in 20% and 80% of subjects at ages 82 and 97 years, respectively. Blood folate and physical activity at age 70 years correlated positively and body mass index (BMI) negatively to visual acuity (VA) > or = 0.8 at ages 82 and 88 years. Smoking at age 70 years correlated to early age-related maculopathy (ARM). Cataract surgery had been performed in 40% of subjects at age 97 years. Surgery 2 years earlier led to a 15% increase in time spent with improved vision. CONCLUSIONS: The deterioration of vision in elderly people is a major health problem, for which 'low' folate status, smoking, 'high' BMI and low physical activity are potential risk factors. Early cataract surgery is also beneficial in very old patients.

Proteasome activity in human lens nuclei and correlation with age, gender and severity of cataract.

PURPOSE: The aim of this study was to measure proteasome activity in human lens nuclei resulting from cataract surgery and in different regions of donor lenses. METHODS: The chymotrypsin-like, the trypsin-like and the peptidylglutamyl-peptide hydrolysing activities of the proteasome were studied using synthetic flourogenic substrates. RESULTS: Proteasome activity did not show any correlation with age of the patients or with gender. Increased opacification of the lens nucleus, as estimated prior to surgery using a 4-grade scale, was significantly correlated with decreased activity of all peptidase activities in the insoluble fraction. In the donor lenses, all peptidase activities were highest in the epithelium and decreased rapidly towards the nucleus. CONCLUSIONS: The present study demonstrates that proteasome activity is preserved in the nucleus of lenses from elderly individuals, although a decrease can be seen with cataract formation. This finding may be of importance for elucidating the mechanism behind the formation of nuclear cataract.

Visual acuity, amblyopia, and ocular pathology in 12- to 13-year-old children in Northern Mexico.

PURPOSE: The aim of this study was to establish visual acuity (VA) and the prevalence of amblyopia and other ocular disorders in a population of 12- to 13-year-old children in Mexico who have not been vision screened. METHODS: A total of 1,035 12- to 13-year-old children were examined in a field study. The examination included VA, stereopsis, cover testing, refractive retinoscopy, and examination of the red reflex and posterior pole. In cases with unexplained subnormal VA, visually evoked potential/visually evoked response was also performed. RESULTS: A >or=20/20 in at least one eye was found in 93% of the subjects. Bilateral VA

Astigmatic axis and amblyopia in childhood.

PURPOSE: This study is part of a larger project whose aim is to evaluate the relationship between refractive errors and amblyopia. In an earlier study, we showed that there is a substantial increase in the prevalence of amblyopia among children with oblique astigmatism. To further evaluate this relationship, we examined children with astigmatisms of 1 dioptre or more and varying directions of the astigmatic axes. METHODS: Two groups of astigmatic children, with oblique and orthogonal astigmatism, respectively, were selected for the study at 1 year of age via a general health screening programme. The most emmetropic axis was identified in each child and used in the study. Visual acuity (VA) was tested when the children were between 4 and 4.5 years of age. The presence of amblyopia, defined as difference in VA between the eyes of 0.1 log unit or more, and any increase in acuity following occlusion therapy were noted. RESULTS: The angle of the astigmatic axis strongly relates to the risk of developing amblyopia. Axes +/- 15 degrees from the main axes did not affect the risk of amblyopia but oblique astigmatism significantly increased the risk of developing amblyopia (p = 0.0024). CONCLUSIONS: The results accord with earlier findings that oblique astigmatism increases the risk of developing amblyopia.