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Kongsberg Vision Meeting was arranged at Buskerud University College inKongsberg for the third time on October 8, 2010. Rigmor C. Baraas and GauteT. Einevoll organized the meeting. Keynote speakers were Joseph Carroll fromthe Medical College of Wisconsin, Milwaukee (USA) and Espen Hartveit fromDepartment of Biomedicine, University of Bergen, Bergen (Norway).

The Ishihara pseudoisochromatic (PIC) plate test is the most used test for identifying red-green colour-deficient individuals, but it is not known how the Ishihara results compare with that of genetics testing. Here, the outcome of genotype analysis of OPN1LW and OPN1MW was compared with that of the Ishihara (24-plate ed., 1964) and the Hardy-Rand-Rittler (4th ed. 2002) PIC plate tests.Healthy participants with normal habitual visual acuity (n = 454, 16-24 years; 193 males; logMAR ≤ 0.00) gave saliva samples for opsin gene analysis and performed the two PIC plate tests as part of a cross-sectional study. The criteria for failing the PIC tests were according to manufacturers' instructions. DNA was extracted and used in genotyping assays of OPN1LW and OPN1MW genes from each participant using the Agena MassArray genotyping system.Ten male (5.2%) and 3 (1.1%) female participants were identified as red-green colour deficient based on PIC tests alone. The combination of MassArray and PIC test results identified 10.4% of male and 0.8% of female participants to be colour deficient (males: 0.5% protan and 9.9% deutan; females: 0.8% deutan). Hardy-Weinberg calculations based on male frequencies from combining the MassArray and the PIC test results gave female frequency estimates of colour deficiency and carriers closely matching measured frequencies.MassArray identified twice as many colour-deficient males as identified from PIC tests alone. Combining results from MassArray and the PIC tests proves to be more reliable than any single test at correctly identifying red-green colour-deficient individuals and carriers.

To investigate the diurnal rhythms in the human eye in winter and summer in southeast Norway (latitude 60°N).Eight measures (epochs) of intraocular pressure, ocular biometry, and optical coherence tomography were obtained from healthy participants (17-24 years of age) on a mid-winter's day (n = 35; 6 hours of daylight at solstice) and on a day the following summer (n = 24; 18 hours of daylight at solstice). Participants wore an activity monitor 7 days before measurements. The epochs were scheduled relative to the individual's habitual wake and sleep time: two in the day (morning and midday) and six in the evening (every hour until and 1 hour after sleep time). Saliva was collected for melatonin. A linear mixed-effects model was used to determine significant diurnal variations, and a sinusoid with a 24-hour period was fitted to the data with a nonlinear mixed-effects model to estimate rhythmic statistics.All parameters underwent significant diurnal variation in winter and summer (Plt; 0.002). A 1-hour phase advance was observed for melatonin and ocular axial length in the summer (Plt; 0.001). The degree of change in axial length was associated with axial length phase advance (R2 = 0.81, Plt; 0.001) and choroidal thickening (R2 = 0.54, Plt; 0.001) in summer.Diurnal rhythms in ocular biometry appear to be synchronized with melatonin secretion in both winter and summer, revealing seasonal variation of diurnal rhythms in young adult eyes. The association between axial length and seasonal changes in the phase relationships between ocular parameters and melatonin suggests a between-individual variation in adaptation to seasonal changes in ocular diurnal rhythms.

Uncorrected vision anomalies may cause headaches and may affect reading and academic performance. The purpose of this study was to quantify the frequency of vision anomalies, frequency of eye examinations, and use of corrective eye wear in adolescents in Norway, and to explore whether such vision anomalies affect reading test results or frequency of headaches. A cross-sectional study was performed in 436 adolescents (42.0% males) aged 16–19 years living in South-East Norway. Cycloplegic autorefraction, habitual stereoacuity, and habitual monocular amplitudes of accommodation were measured, and all participants reported the frequency of eye examinations, the use of spectacles and/or contact lens wear, and the frequency of headaches. Reading comprehension and decoding skills were evaluated for a subgroup of the participants (189 participants, 34.4% males) by their performance in national reading tests. Vision anomalies were defined as having refractive errors, poor habitual stereoacuity, or poor habitual amplitude of accommodation in at least one eye. Overall, 44.0% were classified as having a refractive error, and a total of 61.9% were measured to have vision anomalies. More frequent headaches were associated with poor habitual amplitude of accommodation when adjusted for sex (p = 0.04). The frequency of poor reading comprehension was higher in the group of adolescents with vision anomalies (n = 109, 31.2%) compared with those with no vision anomalies (n = 80, 18.8%; p = 0.05). Of those with vision anomalies, 33.5% had never had an eye examination, and 63.9% reported not wearing a correction. In Norway, there is no mandatory vision screening after 4 years of age. The results here show that a nation-wide programme of regular eye examinations and proper treatment of vision anomalies for all children and adolescents in Norway should be considered. Identifying and treating children with common eye problems in primary and secondary school will improve educational attainment and increase each child’s chances of succeeding in further education.

Purpose Investigate in vivo cone photoreceptor structure in familial aniridia caused by deletion in the PAX6 gene to elucidate the complexity of between-individual variation in retinal phenotype. Design Descriptive case-control study. Participants Eight persons with congenital aniridia (40–66 yrs) from 1 family and 33 normal control participants (14–69 yrs), including 7 unaffected family members (14–53 yrs). Methods DNA was isolated from saliva samples and used in polymerase chain reaction analysis to amplify and sequence exons and intron or exon junctions of the PAX6 gene. High-resolution retinal images were acquired with OCT and adaptive optics scanning light ophthalmoscopy. Cone density (CD; in cones per square millimeter) and mosaic regularity were estimated along nasal–temporal meridians within the central 0° to 5° eccentricity. Horizontal spectral-domain OCT line scans were segmented to analyze the severity of foveal hypoplasia (FH) and to measure retinal layer thicknesses. Main Outcomes and Measures Within-family variability in macular retinal layer thicknesses, cone photoreceptor density, and mosaic regularity in aniridia compared with normal control participants. Results DNA sequencing revealed a known PAX6 mutation (IV2-2delA). Those with aniridia showed variable iris phenotype ranging from almost normal appearance to no iris. Four participants with aniridia demonstrated FH grade 2, 2 demonstrated grade 3 FH, and 1 demonstrated grade 4 FH. Visual acuity ranged from 0.20 to 0.86 logarithm of the minimum angle of resolution. Adaptive optics scanning light ophthalmoscopy images were acquired from 5 family members with aniridia. Foveal CD varied between 19 899 and 55 128 cones/mm2 with overlap between the foveal hypoplasia grades. Cone density was 3 standard deviations (SDs) or more less than the normal mean within 0.5°, 2 SDs less than the normal mean at 0.5° to 4°, and more than 1 SD less than the normal mean at 5° retinal eccentricity. Conclusions The results showed considerable variability in foveal development within a family carrying the same PAX6 mutation. This, together with the structural and functional variability within each grade of foveal hypoplasia, underlines the importance of advancing knowledge about retinal cellular phenotype in aniridia.

Risk factor analysis provides an important basis for developing interventions for any condition. In the case of myopia, evidence for a large number of risk factors has been presented, but they have not been systematically tested for confounding. To be useful for designing preventive interventions, risk factor analysis ideally needs to be carried through to demonstration of a causal connection, with a defined mechanism. Statistical analysis is often complicated by covariation of variables, and demonstration of a causal relationship between a factor and myopia using Mendelian randomization or in a randomized clinical trial should be aimed for. When strict analysis of this kind is applied, associations between various measures of educational pressure and myopia are consistently observed. However, associations between more nearwork and more myopia are generally weak and inconsistent, but have been supported by meta-analysis. Associations between time outdoors and less myopia are stronger and more consistently observed, including by meta-analysis. Measurement of nearwork and time outdoors has traditionally been performed with questionnaires, but is increasingly being pursued with wearable objective devices. A causal link between increased years of education and more myopia has been confirmed by Mendelian randomization, whereas the protective effect of increased time outdoors from the development of myopia has been confirmed in randomized clinical trials. Other proposed risk factors need to be tested to see if they modulate these variables. The evidence linking increased screen time to myopia is weak and inconsistent, although limitations on screen time are increasingly under consideration as interventions to control the epidemic of myopia.

Purpose Many people experience unilateral degraded vision, usually owing to a developmental or age-related disorder. There are unresolved questions regarding the extent to which such unilateral visual deficits impact on sensorimotor performance; an important issue as sensorimotor limitations can constrain quality of life by restricting ‘activities of daily living’. Examination of the relationship between visual deficit and sensorimotor performance is essential for determining the functional implications of ophthalmic conditions. This study attempts to explore the effect of unilaterally degraded vision on sensorimotor performance. Methods In Experiment 1 we simulated visual deficits in 30 participants using unilateral and bilateral Bangerter filters to explore whether motor performance was affected in water pouring, peg placing, and aiming tasks. Experiment 2 (n = 74) tested the hypothesis that kinematic measures are associated with visuomotor deficits by measuring the impact of small visual sensitivity decrements created by monocular viewing on sensorimotor interactions with targets presented on a planar surface in aiming, tracking and steering tasks. Results In Experiment 1, the filters caused decreased task performance—confirming that unilateral (and bilateral) visual loss has functional implications. In Experiment 2, kinematic measures were affected by monocular viewing in two of three tasks requiring rapid online visual feedback (aiming and steering). Conclusions Unilateral visual loss has a measurable impact on sensorimotor performance. The benefits of binocular vision may be particularly important for some groups (e.g. older adults) where an inability to complete sensorimotor tasks may necessitate assisted living. There is an urgent need to develop rigorous kinematic approaches to the quantification of the functional impact of unilaterally degraded vision and of the benefits associated with treatments for unilateral ophthalmic conditions to enable informed decisions around treatment.

The prevalence of myopia is increasing extensively worldwide. The number of people with myopia in 2020 is predicted to be 2.6 billion globally, which is expected to rise up to 4.9 billion by 2050, unless preventive actions and interventions are taken. The number of individuals with high myopia is also increasing substantially and pathological myopia is predicted to become the most common cause of irreversible vision impairment and blindness worldwide and also in Europe. These prevalence estimates indicate the importance of reducing the burden of myopia by means of myopia control interventions to prevent myopia onset and to slow down myopia progression. Due to the urgency of the situation, the European Society of Ophthalmology decided to publish this update of the current information and guidance on management of myopia. The pathogenesis and genetics of myopia are also summarized and epidemiology, risk factors, preventive and treatment options are discussed in details.

Purpose: To investigate the association between PAX6 genotype and macular morphology in congenital aniridia. Methods: The study included 37 participants (15 males) with congenital aniridia (aged 10–72 years) and 58 age-matched normal controls (18 males). DNA was isolated from saliva samples. PAX6 exons, intron/exon junctions, and known regulatory regions were amplified in PCR and sequenced. Multiplex ligation-dependent probe amplification (MLPA) was performed to detect larger deletions or duplications in PAX6 or known cis-regulatory regions. Spectral-domain optical coherence tomography images were acquired and segmented semiautomatically. Mean thicknesses were calculated for inner and outer retinal layers within the macula along nasal and temporal meridians. Results: Mutations in PAX6 or regulatory regions were found in 97% of the participants with aniridia. Foveal hypoplasia was observed in all who had a mutation within the PAX6 gene. Aniridic eyes had thinner outer retinal layers than controls, but with large between-individual variation (mean ± SD, 156.3 ± 32.3 µm vs 210.8 ± 12.3 µm, P < 0.001). Parafoveal and perifoveal inner and outer retinal layers were thinner in aniridia. Participants with mutations in noncoding PAX6 regions had thicker foveal outer retinal layers than those with mutations in the PAX6 coding regions (P = 0.04) and showed signs of postnatal development and maturation. Mutations outside the PAX6 gene were associated with the mildest retinal phenotypes. Conclusions: PAX6 mutations are associated with significant thinning of macular inner and outer retinal layers, consistent with misdirected retinal development resulting in abnormal foveal formation and reduced number of neurons in the macula, with mutations in PAX6 coding regions giving the worst outcome.

Here we present evidence implicating disrupted RNA splicing as a potential cause of inherited tritan color vision. Initially we tested 51 subjects for color vision deficiencies. One made significant tritan errors; the others were classified as normal trichromats. The putative tritan subject was the only one of the 51 subjects found to be heterozygous for an OPN1SW gene mutation that disrupts RNA splicing in an in vitro assay. In order to gather further support for the role of the splicing mutation in tritan color vision, the putative tritan subject’s mother and sister were examined. They also made tritan errors and had the same OPN1SW gene mutation.

To characterize the association between foveal shape and cone and retinal pigment epithelium (RPE) cell topographies in healthy humans.Multimodal adaptive scanning light ophthalmoscopy and optical coherence tomography (OCT) were used to acquire images of foveal cones, RPE cells, and retinal layers in eyes of 23 healthy participants with normal foveas. Distributions of cone and RPE cell densities were fitted with nonlinear mixed-effects models. A linear mixed-effects model was used to examine the relationship between cone and RPE inter-cell distances and foveal shape as obtained from the OCT scans of retinal thickness.The best-fit model to the cone densities was a power function with a nasal-temporal asymmetry. There was a significant linear relationship among cone and RPE cell spacing, foveal shape, and foveal cell topography. The model predictions of the central 10° show that the contributions of both the cones and RPE cells are necessary to account for foveal shape.The results indicate that there is a strong relationship between cone and RPE cell spacing and the shape of the human adolescent and adult fovea. This finding adds to the existing evidence of the critical role that the RPE serves in fetal foveal development and through adolescence, possibly via the imposition of constraints on the number and distribution of foveal cones.

This editorial highlights the scope of the topic that need to be examined further in the field of children’s vision screening. We hope that by making vision screening a special topic in SJOVS we can encourage collaboration between groups of researchers, clinicians and students and help in the development of evidence-based solutions to the current problems facing vision screening across the world. Of course, identifying eye and vision problems represents only the first stage in a screening process. It is important to mention that any screening programme requires several follow up steps to be successful. Good access to further examination for screening is required and affordable spectacles need to be provided. A mechanism of follow up is also important as, once dispensed, the spectacles need to be worn appropriately. Failure to address any of these issues will limit the benefits of a screening programme and innovative methods of addressing these issues are encouraged.

This work is licensed under a Creative Commons Attribution 4.0 International License. PURPOSE. To examine, in Norwegian adolescents, to what degree emmetropia and low hyperopia were maintained from 16 to 18 years of age, and if this was the case, whether it was associated with continued coordinated ocular growth. METHODS. Cycloplegic autorefraction and ocular biometry, including crystalline lens thickness, were measured in 93 Norwegian adolescents (mean age: 16.7 6 0.3 years; 63.4% females) and repeated after 2 years. Crystalline lens power was determined by ray tracing over a 1-mm pupil, based on the Gullstrand-Emsley model. Serum vitamin D3 concentration was measured at follow-up. RESULTS. Emmetropia and low hyperopia (0.50 diopters [D] < spherical equivalent refractive error [SER] < þ2.00 D) were present in 91.4% at baseline and 89.2% at follow-up. The emmetropes and low hyperopes who maintained their refractive error exhibited continued ocular axial growth (þ0.059 6 0.070 mm) together with a decrease in crystalline lens power (0.064 6 0.291 D) and a deepening of the anterior chamber (þ0.028 6 0.040 mm). Thinning of the crystalline lens was found in 24%. Overall, the negative change in SER was larger in those with the most negative SER at baseline (R2 ¼ 0.178, P < 0.001), and was associated with increases in vitreous chamber depth and in crystalline lens power (R2 ¼ 0.752, P < 0.001), when adjusted for sex. There was no difference in vitamin D3 level between those who exhibited negative versus positive changes in refractive error. CONCLUSIONS. The results show that emmetropic and low hyperopic eyes were still growing in late adolescence, with refractive errors being maintained through a coordinated decrease in crystalline lens power.

In an online OSA Incubator Meeting, top industry and academic researchers explored the importance of accounting for aspects of the human visual system to take augmented and virtual reality to the next step.

The relationships between perifoveal measures of achromatic-, L- and M-cone acuity and retinal structure were investigated in healthy young males. Thirty-two males, aged 20-39years, with normal foveal logMAR letter acuity and no observed ocular abnormalities participated in the study. Achromatic and isolated L- and M-cone spatial acuity was measured in the dominant eye with a Sloan E letter of 90% achromatic decrement contrast or 23% increment cone contrast, respectively. Separately, the central part of the same eye was imaged with high-resolution spectral-domain optical coherence tomography (SD-OCT) and adaptive optics ophthalmoscopy (AOO). Thickness measures and cone density in the fovea and parafoveal region were not correlated with perifoveal structural measures. A significant correlation was observed between thicker retinal pigment epithelium (RPE) complex, higher cone density and better L-cone logMAR at 5deg eccentricity, but not for achromatic or M-cone logMAR. The results imply that single letter perifoveal L-cone acuity, rather than achromatic acuity, may provide a useful measure for assessing the structure-function relationship and detecting early changes in the perifoveal cone mosaic.

PURPOSE. To investigate fundus autofluorescence (FAF) and other fundus manifestations in congenital aniridia. METHODS. Fourteen patients with congenital aniridia and 14 age- and sex-matched healthy controls were examined. FAF images were obtained with an ultra-widefield scanning laser ophthalmoscope. FAF intensity was quantified in the macular fovea and in a macular ring surrounding fovea and related to an internal reference within each image. All aniridia patients underwent an ophthalmologic examination, including optical coherence tomography and slitlamp biomicroscopy. RESULTS. Mean age was 28.4 +/- 15.0 years in both the aniridia and control groups. Fovea could be defined by subjective assessment of FAF images in three aniridia patients (21.4%) and in all controls (P = 0.001). Mean ratio between FAF intensity in the macular ring and fovea was 1.01 +/- 0.15 in aniridia versus 1.18 +/- 0.09 in controls (P = 0.034). In aniridia, presence of foveal hypoplasia evaluated by biomicroscopy correlated with lack of foveal appearance by subjective analyses of FAF images (P = 0.031) and observation of nystagmus (P = 0.009). CONCLUSIONS. Aniridia patients present a lower ratio between FAF intensity in the peripheral and central macula than do healthy individuals. Both subjective and objective analyses of FAF images are useful tools in evaluation of foveal hypoplasia in aniridia. Funding Agencies|Aniridia Norway (Oslo, Norway); Jon Larsen foundation (Tonsberg, Norway); Inger Holms memorial foundation (Oslo, Norway); Norwegian Association of the Blind and Partially Sighted (Oslo, Norway); Norwegian Ophthalmological Society (Oslo, Norway); Department of Ophthalmology at Oslo University Hospital (Oslo, Norway); National Centre for Optics, Vision and Eye Care at the University of South-Eastern Norway; European Union Seventh Framework Program (FP7-PEOPLE-2013-COFUND) [609020]

This is an open access article under the CC BY license. Colour vision deficiencies are common in humans and occur both as a consequence of inherited cone opsin mutations, altering the number or function of the different cone types expressed in the retina, and acquired through secondary disruption of cone function and structure. This review describes recent advances made in understanding colour vision deficiencies from combining knowledge about cone opsin genes with single-cone imaging in living humans. Examination of the effect of the opsin gene mutations upon the cone mosaic and colour vision phenotypes shows that not all inherited colour vision deficiencies are stationary and some inherited congenital eye diseases may cause impaired colour vision as a consequence of arrested development. The authors have received support from the Research Council of Norway, the Oslofjord Fundand An iridia Norway for their research.

Published by Elsevier Ltd. This is an open access article under the CC BY license. Elsevier Vision Research Volume 162, September 2019, Pages 20-28 Vision Research The association between L:M cone ratio, cone opsin genes and myopia susceptibility Author links open overlay panelLene A.HagenaSolveigArnegardaJames A.KuchenbeckerbStuart J.GilsonaMaureenNeitzbJayNeitzbRigmor C.Baraasa Show more https://doi.org/10.1016/j.visres.2019.06.006Get rights and content Under a Creative Commons licenseopen access Highlights • Low myopia prevalence in Norwegian adolescents. • High mean L:M cone ratio in both Norwegian males and females. • High L:M cone ratios in females were associated with lower degree of myopia. • Myopia was more frequent in females heterozygous for L opsin exon 3 haplotypes. • Milder versions of L exon 3 skipping variants may play a role in common myopia. Abstract In syndromic forms of myopia caused by long (L) to middle (M) wavelength (L/M) interchange mutations, erroneous contrast signals from ON-bipolar cells activated by cones with different levels of opsin expression are suggested to make the eye susceptible to increased growth. This susceptibility is modulated by the L:M cone ratio. Here, we examined L and M opsin genes, L:M cone ratios and their association with common refractive errors in a population with low myopia prevalence. Cycloplegic autorefraction and ocular biometry were obtained for Norwegian genetically-confirmed normal trichromats. L:M cone ratios were estimated from spectral sensitivity functions measured with full-field ERG, after adjusting for individual differences in the wavelength of peak absorption deduced from cone opsin genetics. Mean L:M cone ratios and the frequency of alanine at L opsin position 180 were higher in males than what has been reported in males in populations with high myopia prevalence. High L:M cone ratios in females were associated with lower degree of myopia, and myopia was more frequent in females who were heterozygous for L opsin exon 3 haplotypes than in those who were homozygous. The results suggest that the L:M cone ratio, combined with milder versions of L opsin gene polymorphisms, may play a role in common myopia. This may in part explain the low myopia prevalence in Norwegian adolescents and why myopia prevalence was higher in females who were heterozygous for the L opsin exon 3 haplotype, since females are twice as likely to have genetic polymorphisms carried on the X-chromosome.

There is a need to better understand the peripheral optics of the human eye and their correction. Current eye models have some limitations to accurately predict the wavefront errors for the emmetropic eye over a wide field. The aim here was to develop an anatomically correct optical model of the human eye that closely reproduces the wavefront of an average Caucasian-only emmetropic eye across a wide visual field. Using an optical design program, a schematic eye was constructed based on ocular wavefront measurements of the right eyes of thirty healthy young emmetropic individuals over a wide visual field (from 40° nasal to 40° temporal and up to 20° inferior field). Anatomical parameters, asymmetries, and dispersion properties of the eye’s different optical components were taken into account. A geometry-independent gradient index model was employed to better represent the crystalline lens. The RMS wavefront error, wavefront shapes, dominant Zernike coefficients, nasal-temporal asymmetries, and dispersion properties of the developed schematic eye closely matched the corresponding measured values across the visual field. The developed model can help in the design of wide-field ophthalmic instruments and is useful in the study and simulations of the peripheral optics of the human eye.

PURPOSE: Investigate in-vivo cone photoreceptor structure in familial aniridia caused by a deletion in the PAX6 gene to elucidate the complexity of between-individual variation in retinal phenotype. DESIGN: Descriptive case-control study PARTICIPANTS: Eight persons with congenital aniridia (5 males; aged 40–66) from one family and 33 normal controls (14 males, aged 14–69 yrs), including seven unaffected family members (3 males; aged 14–53yrs). METHODS: DNA was isolated from saliva samples and used in PCR to amplify and sequence exons and intron/exon junctions of the PAX6 gene. Fluorescent DNA sequencing was performed on both DNA strands. High-resolution retinal images were acquired with Heidelberg Spectralis (SD-OCT2) and Adaptive optics scanning light ophthalmoscopy (AOSLO). Cone density (CD; cones/mm(2)) and mosaic regularity were estimated along nasal-temporal meridians within the central 0–5° eccentricity. Horizontal SD-OCT line scans were segmented to analyze severity of foveal hypoplasia and measure retinal layer thicknesses. MAIN OUTCOMES AND MEASURES: Within-family variability in macular retinal layer thicknesses, cone photoreceptor density and mosaic regularity in aniridia compared with normal controls. RESULTS: DNA sequencing revealed a known PAX6 mutation (IV2-2delA). Those with aniridia had variable iris phenotype ranging from almost normal appearance to no iris. Four with aniridia had FH grade 2, two had grade 3 and one had grade 4. Visual acuity ranged from 0.20–0.86 logMAR. AOSLO images were acquired of five family members with aniridia. Foveal CD varied between 19899 and 55128 cones/mm(2) with overlap between the foveal hypoplasia grades. CD was ≥3 SD below the normal mean within 0.5° ≥2 SD below the normal mean at 0.5°–4° and >1SD below the normal m ean at 5°retinal eccentricity. CONCLUSIONS: The results show considerable variability in foveal development within a family carrying the same PAX6 mutation. This, together with the structural and functional variability within each grade of foveal hypoplasia, underlines the importance of advancing knowledge about retinal cellular phenotype in aniridia.

This feature issue of the Journal of the Optical Society of America A (JOSA A) reflects the basic and applied research interests of members of the color vision community. Most of the articles stem from presentations at the 24th Biennial Symposium of the International Colour Vision Society (ICVS).

Chromatic contrast sensitivity may be a more sensitive measure of an individual's visual function than achromatic contrast sensitivity. Here, the first aim was to quantify individual- and age-related variations in chromatic contrast sensitivity to a range of spatial frequencies for stimuli along two complementary directions in color space. The second aim was to examine whether polymorphisms at specific amino acid residues of the L- and M-opsin genes (OPN1LW and OPN1MW) known to affect spectral tuning of the photoreceptors could influence spatio-chromatic contrast sensitivity. Chromatic contrast sensitivity functions were measured in 50 healthy individuals (20-71 years) employing a novel pseudo-isochromatic grating stimulus. The spatio-chromatic contrast sensitivity functions were found to be low pass for all subjects, independent of age and color vision. The results revealed a senescent decline in spatio-chromatic contrast sensitivity. There were considerable between-individual differences in sensitivity within each age decade for individuals 49 years old or younger, and age did not predict sensitivity for these age decades alone. Forty-six subjects (including a color deficient male and eight female carriers) were genotyped for L- and M-opsin genes. The Ser180Ala polymorphisms on the L-opsin gene were found to influence the subject's color discrimination and their sensitivity to spatio-chromatic patterns. The results expose the significant role of neural and genetic factors in the deterioration of visual function with increasing age.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. East Asia has experienced an excessive increase in myopia in the past decades with more than 80% of the younger generation now affected. Environmental and genetic factors are both assumed to contribute in the development of refractive errors, but the etiology is unknown. The environmental factor argued to be of greatest importance in preventing myopia is high levels of daylight exposure. If true, myopia prevalence would be higher in adolescents living in high latitude countries with fewer daylight hours in the autumn-winter. We examined the prevalence of refractive errors in a representative sample of 16–19-year-old Norwegian Caucasians (n = 393, 41.2% males) in a representative region of Norway (60° latitude North). At this latitude, autumn-winter is 50 days longer than summer. Using gold-standard methods of cycloplegic autorefraction and ocular biometry, the overall prevalence of myopia [spherical equivalent refraction (SER) ≤−0.50 D] was 13%, considerably lower than in East Asians. Hyperopia (SER ≥ + 0.50 D), astigmatism (≥1.00 DC) and anisometropia (≥1.00 D) were found in 57%, 9% and 4%. Norwegian adolescents seem to defy the world-wide trend of increasing myopia. This suggests that there is a need to explore why daylight exposure during a relatively short summer outweighs that of the longer autumn-winter. The study was funded by the University of South-Eastern Norway and Regional Research Funds: The Oslofjord Fund Norway Grant No. 249049 (RCB). LAH holds a PhD position funded by the Norwegian Ministry of Education and Research.

AimsTo investigate the aetiology and characteristics of dry eye disease (DED) in a Nordic cohort of patients with congenital aniridia.MethodsThirty-four Norwegian and one Danish subject with congenital aniridia and 21 healthy controls were examined. All subjects underwent an extensive dry eye examination, including evaluation of meibomian glands (MGs) by meibography, measurement of tear production and tear film osmolarity and grading of vital staining of the ocular surface. Moreover, slit-lamp biomicroscopy was undertaken, including grading of aniridia-associated keratopathy (AAK).ResultsMean tear film osmolarity was significantly higher (314±11 mOsmol/L) in patients with aniridia compared with the healthy control group (303±11 mOsmol/L, p=0.002). Vital staining score was higher in the aniridia group (4.3±3.0) compared with healthy controls (2.4±1.6, p=0.02). The degree of staining correlated positively with the stage of AAK (r=0.44, p=0.008) and negatively with corneal sensitivity (r=−0.45, p=0.012). Number of expressible MGs was lower in aniridia subjects (2.9±1.6) than in controls (4.0±1.3, p=0.007). MG loss, staged from 0 to 3, was higher in the aniridia group than in the control group, both in upper eyelid (0.86±0.89 vs 0.10±0.31, p=0.001) and lower eyelid (0.94±0.73 vs 0.30±0.47, p=0.003). Computerised analyses showed thinning (p=0.004) and lower density (pConclusionsPatients with congenital aniridia demonstrate increased tear film osmolarity, ocular surface staining, loss of MGs and lower MG expressibility. We conclude that meibomian gland dysfunction and keratopathy are related to development of DED in aniridia.

BackgroundSmall hard macular drusen can be observed in the retina of adults as young as 18 years of age. Here, we seek to describe the in vivo topography and geometry of these drusen.MethodsRetinal images were acquired in young, healthy adults using colour fundus photography, spectral domain optic coherence tomography (SD-OCT), reflectance flood-illuminated adaptive optic ophthalmoscopy (AO flood) and reflectance adaptive optic scanning light ophthalmoscopy (AOSLO) in both confocal and non-confocal split-detection modalities. Small bright yellow hard drusen within a 10 degree radius from the foveal centre were characterised.ResultsSmall hard drusen were seen on colour photographs in 21 out of 97 participants and 26 drusen in 12 eyes in 11 participants were imaged using the full protocol. Drusen were easily identifiable in all modalities, except a few very small ones, which were not visible on SD-OCT. On AOSLO images, these drusen appeared as round, oval or lobular areas (up to three lobules) of diameter 22–61 µm where cone photoreceptor reflectivity and density was decreased (p=0.049). This was usually associated with discrete thickening of the retinal pigment epithelium (RPE) complex.ConclusionHigh lateral resolution imaging of small lobular hard retinal drusen suggests formation through the confluence of two or more smaller round lesions. The outline and size of these smaller lesions corresponds to 1–4 RPE cells. Prospective longitudinal studies are needed to determine the ultimate fate of small hard drusen and their potential relation to age-related macular degeneration.