Search

Background Visual outcomes after primary tumour treatment of uveal melanoma (UM) have been investigated repeatedly. This study evaluates the correlation between best-corrected visual acuity (BCVA) before treatment with clinicopathological factors and patient survival. Subjects/Methods Pre-treatment BCVA was examined in relation to tumour dimensions and location, and survival in a retrospective cohort of 1809 patients who underwent plaque brachytherapy. BCVA was also correlated to tumour histological factors in a second cohort of 137 enucleated eyes. Results The mean BCVA of the tumour eye prior to plaque brachytherapy was LogMAR 0.42 (SD 0.46). Patients with low BCVA (LogMAR ≥ 1.00) did not differ in age (p = 0.19) and had similar frequency of ciliary body involvement (p = 0.99) but had tumours with greater apical thickness (p p p p > 0.004). Patients with low BCVA had greater incidence of UM-related mortality in competing risk analysis (p = 0.0019) and shorter overall survival (p Conclusions UM patients with low BCVA before primary tumour treatment have a worse prognosis, likely related to increased tumour dimensions. Future studies should examine the prognostic significance of BCVA in relation to macula-involving retinal detachment and genetic factors.

Purpose: To evaluate the precision of individual and combined macula and optic disc volumetric analysis, and the agreement between these two scan modes with spectral domain optical coherence tomography (OCT).Methods: Macular and optic disc volumetric measurements were performed with individual and combined scan protocols in one eye of 75 healthy subjects. Three repeated measurements were performed with each protocol. From the macular area, retinal thickness in nine different sectors and ganglion cell complex thickness in eight different sectors were analyzed from both scan modes. From the optic disc area, the peripapillary retinal nerve fiber layer (pRNFL) thickness in 12 clock sectors and the optic disc parameters were evaluated. For all the parameters, repeatability limit and agreement analysis were performed.Results: For the retinal thickness measurements in macula, the combined scan had two to three times larger repeatability limit than the individual scan for all the sectors except the central sector, where the repeatability limit was five times larger. The limits of agreement intervals were lower than 20 μm for all sectors, except the central. The ganglion cell complex measurements also had larger repeatability limits for the combined scans, and the limits of agreement intervals were Conclusion: The individual macula and optic disc scans had better repeatability than the combined scan mode, and the two scan modes cannot be used interchangeability due to the wide limits of agreement.

Visual outcomes after treatment of uveal melanoma have been investigated repeatedly. In this paper, we evaluate the correlation between visual acuity (VA) prior to enucleation, presenting symptoms and findings upon histopathological examination of eyes and tumors. Sixty nine patients were included. Their mean best corrected visual acuity (BCVA) prior to enucleation was LogMAR 0.80 (SD 0.70). Patients that reported low VA or blurry vision did not have lower BCVA upon refraction (p=0.34). Patients with low BCVA had tumors with greater apical tumor thickness (p=0.027), basal diameter (p=0.012) and stage (p=0.014). The experience of a shadow in the visual field correlated with presence of vasculogenic mimicry in the tumor (p

SIGNIFICANCE Non-immunocompromised people living with HIV (NIPLHIV) share a similar immunocompetence to non-HIV (HIV) people with an elevated cluster of differentiation 4 (CD4) count in the era of antiretroviral therapy (ART). This has reduced the incidence of HIV retinopathy, thus raising the question of the integrity of the retinal morphology in NIPLHIV with longer life expectancy. PURPOSE The study assessed the retinal thickness and volume of NIPLHIV without retinitis on ART and attempted to find associations with linear parameters of cerebral atrophy. METHODS The study was conducted at a public hospital in South Africa. All people living with HIV were on ART with CD4 counts above 350 cells/mm3 and viral loads less than 10,000 copies/mL. The Heidelberg Spectralis ocular coherence tomographer assessed the retinal thickness and volume for comparison between 30 NIPLHIV and 30 HIV-negative participants. A subset of the HIV group obtained a computed tomography scan to determine the bicaudate ratio and the sylvian fissure ratio to assess cerebral atrophy. Independent t tests were performed to identify differences in retinal thickness and volume. Multivariate linear regressions measured associations between retinal thickness and volume with cerebral atrophy. RESULTS The NIPLHIV group had a thicker mean global temporal subfields at Early Treatment Diabetic Retinopathy Study (ETDRS) 3 mm (P = .047) and ETDRS 6 mm (P = .03). The mean global temporal subfield volume at ETDRS 3 mm was also increased in the NIPLHIV group (P = .02). Nasal macula retinal nerve fiber layer thickness and the inferior inner nuclear layer macula volume were directly related to the bicaudate ratio, whereas the volumes at the outer retinal layer subfields of the macula were inversely related to sylvian fissure ratio in NIPLHIV. CONCLUSIONS Macula thickness and volumetric differences do exist in NIPLHIV. Practitioners should keep NIPLHIV under retinal morphometric surveillance because they live longer. Associations of cerebral atrophy with retinal morphology may be used to monitor cerebral atrophy in NIPLIV on ART.

Background: To evaluate the precision and accuracy of objective refraction measurement obtained with combinations of instrument design and technique. We also compared the performance of the instruments with subjective refraction measurements. Method and analysis: The objective refraction was measured in 71 subjects with three autorefractometers that have different designs and measurement principles (binocular with fogging, binocular without fogging, and monocular with fogging). Repeatability and reproducibility metrics were calculated for the objective refraction measurements. The agreement of the objective refraction measurements between the three instruments and the agreement with the subjective refraction measurements were evaluated. Results: All three autorefractometers had repeatability and reproducibility limits smaller than 0.70D. The smallest difference (0.10D) in the spherical equivalent was seen between the two binocular instruments. Compared with the subjective refraction, the binocular without fogging technique had the smallest mean difference in spherical equivalent (&lt, 0.20D) whereas the binocular fogging technique had the smallest limit of agreement interval (1.00D). For all comparisons, the mean difference and limit of agreement interval for the cylindrical components were lower than 0.10D and 0.75D, respectively. Conclusion: All three instruments evaluated had good repeatability and reproducibility. The binocular fogging technique provided the best agreement with subjective refraction.

Background: People living with HIV (PLHIV) on antiretroviral therapy (ART) without retinitis may not have a healthy retinal structure. Aim: To examine the impact of the virus together with the ART medication in PLHIV without retinitis. Methods: This review used the following databases: PubMed, Google Scholar and EBSCOhost. Search terms included: HIV and/or retinal nerve fibre layer (RNFL); perimetry; colour vision; contrast sensitivity (CS); visual evoked potentials (VEPs); electroretinograms (ERGs); and the brain. All peer-reviewed studies related to PLHIV on ART without retinitis, up until September 2019, were included. Results: The mean RNFL thickness, and superior and inferior zones showed thinning. Affected visual functions include transient pattern VEP and ERG; contrast sensitivity; reduced total error scores on colour vision evaluation; and reduced mean deviation and pattern standard deviations on perimetry. Studies also showed concurrent thinning of the peripapillary retinal nerve fibre layer (ppRNFL) and perimetry, contrast sensitivity and colour vision. All these significant observations were seen at a cluster of differentiation 4 (CD4) count of less than 200 cells/mm 3 in PLHIV on ART with no retinitis. Further to this, studies have also related the retina to grey and white matter changes in PLHIV in the era of ART. A gap in research involves studies on the vascular impact of ART on the retina, which should be factored into studies going forward when studying PLHIV on ART. Conclusion: The decrease in visual function, the RNFL changes and neuro-ophthalmic involvement in PLHIV allow us to recognise the threat to vision loss when factoring in the expected longer lifespan that PLHIV on ART are afforded today.

Background Working in front of computer screens is visually demanding and related to adverse eye symptoms. Occurrence of glare further increases visual fatigue. Objective This paper presents results from an examination of visual ergonomics in control room environments at two Swedish process industries. Methods Visual conditions were examined and evaluated in nine control rooms and eighteen process operators answered questions about their perceived workload and visual experiences. Results When working in the control rooms, the mental workload was rated significantly higher by the participants, compared to experienced performance. The operators further experienced significantly higher visual fatigue and blurred vision compared to double vision and sore eyes. Visual demands were increased in conditions where contrast glare was present, as well as frequent changes of focusing distances, and low contrast between background and characters in computer screens. Conclusions Suboptimal visual working conditions in the control rooms contributes to increased visual demands on the operators. Presence of glare is leading to visual fatigue and an unnecessary high mental load. The findings support the relevance of considering principles of general and visual ergonomics when designing and organizing work in control rooms. Workstation design should also be flexible to allow for individual and contextual adjustments.

[Excerpt] The world’s population is growing older, with persons over the age of 65 being the fastest-growing age group. According to data from World Population Prospects 2019 [1], one in 11 people in the world was over the age of 65 in 2019 (9%), and this number is expected to increase to one in six (16%) by 2050 since life expectancy is also expected to increase from current 72.6 years to 77.1. In 2018, for the first time in history, persons aged 65 or above outnumbered children under five years of age.[...]

BACKGROUND To assess the repeatability and agreement between a new high-resolution optical coherence tomographer (OCT) and a Scheimpflug topographer. MATERIAL AND METHODS Sixty phakic and healthy participants were measured in this study, and one eye per participant was analyzed. Depending on their refractive error, each participant was allocated into a myopic, hyperopic, or emmetropic group. The Cirrus HD-OCT 5000 (Carl Zeiss Meditec, Jena, Germany), and the Sirius Scheimpflug topographer (Costruzione Strumenti Oftalmici, Florence, Italy) were used to take all measurements. RESULTS The repeatability of these instruments to measure the anterior chamber depth, angle-to-angle, thinnest pachymetry, and both nasal and temporal angles was smaller than 0.15 mm, 0.40 mm, 10 µm, and 10 degrees, respectively. However, the repeatability of the Scheimpflug instrument to measure the apex pachymetry was about 15 µm, and for the OCT, it was about 4 µm for all groups. On average, the Sirius Scheimpflug instrument measured shallower anterior chamber depth (about 0.10 mm), shorter angle-to-angle (about 0.5 mm), thinner corneas (approximately 10 µm), and narrower angles (around 5 degrees) for all refractive groups. CONCLUSIONS The repeatability of the Cirrus OCT and Sirius Scheimpflug instrument was good and independent of the refractive error. Nevertheless, to judge whether these instruments could be used interchangeable, clinical criteria are needed.

To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture. The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed. The optical power fluctuated less than 0.5 diopters (D) along the optical zone of each lens. However, the optical power obtained for some lenses did not match with its corresponding nominal one, the maximum difference being 0.5 D. In optical quality, small differences were obtained among all lenses within the same design. Although significant differences were obtained among lenses (P

PurposeTo evaluate the repeatability of the new spectral domain optical coherence tomography (HOCT-1F), and also to evaluate the agreement between vertical and horizontal scan protocols. In addition, we also evaluated the relation between the repeatability and age.MethodsThree consecutive measurements of the inner limiting membrane-retinal pigment epithelium (ILM-RPE), inner limiting membrane-inner plexiform layer (ILM-IPL) from macular horizontal and vertical scans, and inner limiting membrane-retinal nerve fiber layer (ILM-RNFL) from optic disc horizontal scan. 159 subjects were included in the analysis. The within subject standard deviation (Sw) and the repeatability limits (Rlimit) are used to represent the repeatability of the parameters for the different sectors.ResultsThe Sw for the ILM-RPE thickness was less than 3.5 μm for each sector and scan direction. The Sw values varied within the sectors and scan modes, with horizontal scan modes resulting in better values for the horizontal sectors, and vice versa. The Sw for the GCL-IPL thickness was less than 2 μm, and was similar between the vertical and horizontal scan modes for each sector map. For the optic disc scan, the Sw was not symmetric along the clock-hour map sectors, the largest Sw values were seen in the vertical sectors (8.6 μm). The mean difference between the vertical and horizontal scans was less than 2 μm for each retinal thickness sector map. Significant but weak correlation between the Sw and the subject's age was seen in both macular and optic disc scans.ConclusionsThe repeatability of the HOCT-1F to measure the ILM-RPE-, ILM-IPL- and ILM-RNFL-thickness is good. The repeatability of the ILM-RPE thickness is dependent on the scan direction, which should be taken into account when calculating retinal thickness. There is a weak correlation between the repeatability and the subject's age.

This paper presents results from a case study at a Swedish paper mill. The study is part of a larger ongoing research project aiming to investigate visual ergonomics in control room environments. Visual conditions were measured and evaluated in five control rooms, and nine process operators answered questions about perceived workload and visual experience.

Purpose.The aim of the present study was to compare macular thickness in patients with keratoconus (KC) with macular thickness in healthy subjects.Subjects and Methods.Twenty-six patients with KC and 52 control subjects were included. The macular structure was evaluated using a Zeiss Cirrus HD-OCT. The scan pattern used was 512 × 128, which covers an area of approximately 6 × 6 mm of the retina. The cube volume was assessed as well as macular thickness in each of the 9 sectors defined by the software.Results.The mean signal strength was significantly lower in the KC group (mean 8.4, range 6–10) compared with the control group (mean 9.7, range 7–10),P<0.0001(unpairedt-test). There were no significant differences in cube volume (unpairedt-test), cube average thickness, or macular thickness between the KC group and the control subjects in any of the retinal locations (one-way ANOVA).Conclusion.Macular structure as measured by OCT in KC subjects should be expected to lie within the range of age and sex matched controls.

Dyslexia affects 5%-8% of the population of the Western world. While reading, different eye movements are required. Compared to other persons, dyslexics have more and longer fixations, shorter saccade amplitude, a higher percentage of regression, and more fixation disparity when reading. In non-reading situations, dyslexics do not have more binocular problems than others. The aim of the present study was to investigate whether computerized orthoptic vergence training could improve reading ability for dyslexic children.The study was conducted at Ängkärrskolan, Solna, an elementary school exclusively for dyslexic children. Twelve subjects, aged 13-14 years, were trained with RetCorr, a computerized vergence training program. Reading speed was assessed before and after treatment. The results were compared with an age-matched control group.The dyslexic subjects conducted on average 11.75 sessions (±2.53 SD) of orthoptic training over a 5-week period. On average, the number of words read per minute before training were 87.83 (±16.80 SD) and after training 95.58 words (±18.08 SD). The difference was statistically significant (p=0.0066). In the control group, the change was from 85.00 (±19.68 SD) words to 89.37 words (±19.71 SD) over the same time period. This difference was not significant (p=0.1235).Most scientists agree that dyslexia is mainly a phonological impairment. Nevertheless, the results show that vergence treatment might help dyslexics. Larger studies are required to provide guidance in this area.

Reductions of the peripapillary retinal nerve fiber layer (pRNFL) thickness has been indicated even in early-stages of multiple sclerosis (MS). The aim was to investigate the association between pRNFL thickness, measured with optical coherence tomography (OCT), and physical disability and cognitive impairment in MS.465 MS patients and 168 healthy controls (HCs) were included. MS subjects were divided into subgroups according to disease subtype. All subjects underwent OCT examination of all pRNFL quadrants using Canon OCT-HS100. Associations were tested using linear mixed effect models. Physical disability was assessed with the Expanded Disability Status Scale (EDSS) and cognitive function with the Symbol Digit Modalities Test (SDMT).The average pRNFL, inferior pRNFL and temporal pRNFL thicknesses were significantly correlated to both EDSS (-1.0 µm, p 0.01; -1.2 µm, p 0.05; -1.2 µm, p 0.01) and SDMT (0.1 µm, p 0.05; 0.2 µm, p 0.05; 0.2 µm, p 0.01). A significant thickness loss compared with HCs was seen in the average pRNFL and in all quadrants except for the superior quadrant of primary progressive MS. The largest reduction compared with HCs was seen in the temporal pRNFL of PPMS eyes (-15.8 µm; p 0.001).The reduction of average pRNFL, inferior pRNFL and temporal pRNFL thickness is associated with physical and cognitive disability in MS. We suggest the use of temporal pRNFL as a more sensitive outcome as it showed the strongest association to both EDSS and SDMT.

Purpose: To AU3 evaluate the subjective satisfaction in visual stability, night vision complains, and light distortion phenomena, and also the number of hours and days per week of lens wear, in patients with myopia undergoing orthokeratology (OK) treatment for at least 1 year. Methods: A visual analog scale (VAS) questionnaire containing 18 items was administered to 44 patients, 29 women and 15 men (mean age, 24.39 6 9.11 years), with a baseline spherical equivalent refractive error of 22.40 6 0.94 diopters and astigmatism up to 20.5 diopters. Average treatment period by the time of data collection was 19 6 7 months. Patients rated their satisfaction with the correction, with complaints of visual distortion being graded on a scale of 0 to 10, where 0 indicated no discomfort at all. Results: More than 50% of patients skipped lens wear at least 1 night per week. The most common wearing pattern was 6–8 hours a day for 72.7% with 54.5% of patients wearing lenses every 2–3 nights only. Subjective vision scores after lens removal was 9.1 6 1.1 after having worn the lenses and 8.1 6 1.4 after skipping lens wear for 1 night. Subjective vision scores before lens insertion at the end of the day was 6.9 6 2.0 and 5.8 6 2.4, respectively. The number of hours until noticeable blur reduced with increased level of baseline myopia (r = 0.396; P , 0.001). Conclusion: Orthokeratology patients show an irregular wearing pattern after 1 year of treatment that has significant effects on the subjective visual performance over the next day of skipping lens wear. Light distortion under low-light conditions seems to be a transient complication of the treatment and most of the patients report an improvement after the first weeks of treatment., Supported in part by projects PTDC/SAU-BEB/098391/2008//FCOMP-01-0124-FEDER-010897 and PTDC/SAU-BEB/098392/2008//FCOMP-01-0124-FEDER-010898 funded by Fundacao para a Ciencia e Tecnologia (FCT) of Portugal.

Aim: To evaluate the Tobii 1750 Eye Tracker system's usefulness in evaluating reading performance. Material: Twenty healthy subjects, aged 21–33 years, were measured with the Tobii 1750 Eye Tracker while reading two texts with equal readability rating. Reading speed was measured in words read per minute (wpm) from the onset of the first page to the conclusion of the last. Comprehension was enumerated as the ratio of correct answers (%). Eye movements were recorded as time-stamped coordinates of how the eyes moved over the screen. Results: There was a significant difference in reading speed and all eye movements except the saccade/regression ratio. Furthermore there was no significant difference in comprehension between the texts. Conclusion: The results show that texts used for studying reading performance most be chosen carefully as texts of the same linguistic difficulty, fonts, size and spacing can yield differences in reading performance, i.e. readability indexes are most likely not able to differentiate texts in a sophisticated enough manner. Furthermore, the results show that the Tobii system, despite its relative low resolution and sampling frequency, is suitable for evaluation of reading eye movements.

PURPOSE: To assess the precision of the new high-resolution optical coherence tomography (OCT) device to measure anterior segment distances and assess its agreement with a Scheimpflug camera. METHODS: Eighty patients with healthy and phakic eyes were included in this study, and only one eye per participant was analyzed. Each eye was measured three times with the Sirius topographer (Costruzione Strumenti Oftalmici, Florence, Italy) and the Cirrus HD-OCT 5000 (Carl Zeiss Meditec, Jena, Germany). RESULTS: On average, the Sirius topographer measured statistically significantly (P < .05) deeper ACD (approximately 0.07 mm), larger angle-to-angle distance (approximately 0.30 mm), thicker pachymetry (approximately 11 µ m), and wider temporal angle (approximately 6°) than the Cirrus OCT. Nevertheless, the Cirrus OCT measured statistically significantly (P < .05) wider nasal angle (approximately 2°) than the Sirius topographer. The repeatability and reproducibility metrics were similar between devices to measure the ACD (smaller than 0.05 mm), corneal pachymetry (smaller than 5 µ m), and anterior chamber angles (smaller than 5 degrees). Nevertheless, the reproducibility of the Cirrus OCT to measure the angle-to-angle distance was worse than the Sirius topographer, which had values of 0.11 and 0.21 mm, respectively. CONCLUSIONS: The Cirrus OCT and Sirius topographer showed good precision outcomes to measure the anterior segment of the eye. Nevertheless, clinical criteria are needed to judge whether these devices could be used interchangeably. [ J Refract Surg. 2016;32(11):766–772.]

Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient’s accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on the latter is very low, and some concerns still remain about its long-term safety. The present article reviews the published literature on the outcomes after PRL implantation in order to provide a general overview and evaluate its real potential as a surgical refractive option.

The aim of this report is to describe the principles of the fundus autofluorescence (FAF) technique, and to illustrate common findings in normal and abnormal ocular conditions by presenting both colour and FAF images captured with the Canon CR-2PLUS™. The colour and FAF images are discussed in relation to scientifically published reports on FAF findings in similar ocular conditions and with other FAF cameras. Based on our experience the FAF images should be regarded as a supplement to colour fundus images and has highest relevance when it comes to slow progressing conditions rather than acute conditions. At present the knowledge about what FAF shows and how it should be interpreted is broad, and it seems likely that the technique will have a future not only in research and highly specialized retinal evaluations, but also in daily clinical work.

Background: The aim of this study was to compare the intraocular pressure (IOP) and the central corneal thickness (CCT) measurements obtained with the Canon TX-20P™ with IOP measured with Goldmann applanation tonometer (GAT) and the CCT measured with ultrasound (US) pachymetry in healthy eyes. Methods: Thirty one healthy voluntary subjects participated in the study, age ranging from 16 to 81 years (mean age 50.9 years). In total 58 eyes were selected for analysis. All measurements were performed by the same examiner. The measurements were taken in the same order in all subjects: Canon IOP and CCT, Goldmann IOP and US CCT. Results: A strong correlation was found between IOP for both CCT compensated and raw values (R2 0.79 and 0.71 respectively) and CCT (R2 0.80) readings from GAT and US pachymetry as compared with the Canon TX-20P™, however, a small but statistically significant difference was found in both IOP and CCT measurements. Conclusions: The Canon TX-20P™ is a compelling two-in-one non-invasive instrument that allows both IOP and CCT measurements. The Canon TX-20P™ has acceptable agreement for IOP measurements, especially the CCT compensated IOP, as compared with GAT and for CCT when compared with US in healthy subjects. However, it remains to be evaluated if such an agreement can be found in subjects with abnormal IOP and CCT.

Introduction: The most common way to examine vision is to measure visual acuity using letter charts. The Rarebit fovea test was developed for detection of small defects of foveal function at a stage before they cause abnormal visual acuity. In a recent study, the RFT was well tolerated in a smaller group of children between seven and nine years of age; however, the number of subjects in that study was small for the determination of reference values, and therefore the aim of the present study was to establish reference values for a larger group of children aged between six and 10 years and to evaluate the learning effect after repeated tests. Methods: Rarebit fovea test data were collected from a group of 108 subjects aged between six and 10 years as part of a screening program at a compulsory school in Stockholm, Sweden. All subjects had good visual acuity and minor refractive errors. They underwent two Rarebit fovea test examinations on one occasion. Results: Rarebit fovea test results ranged from a median mean hit rate of 94.0 to 97.5 per cent for pre-school and third-year children, respectively. For the entire group of children the median mean hit rate was 96 per cent (range 57 to 100). The third-year children performed significantly better than the pre-school (p < 0.01) and first-year children (p < 0.05). A significant improvement from the first to second test run was noticed in all groups. Conclusion: The Rarebit fovea test proved to be well tolerated among children in a group of six to 10 year olds and more than 90 per cent of children were considered to give reliable results close to what is normal for adults. It would be interesting to further investigate the potential of the Rarebit fovea test for evaluation of foveal function in children.

It is accepted practice to use a spherical equivalent power as an alternative contact lens correction for those patients with lower amounts of astigmatism, allowing for an easier fit, but the blur caused by one diopter of uncorrected astigmatism can reduce acuity of 6/6 to that of about 6/8. This is usually deemed acceptable monocularly, often retaining a good binocular acuity. The purpose of this study is to explore how monocular astigmatic blur may also affect the patient's binocular vision function.A trial frame was outfitted with full correction for 20 healthy subjects (mean age 25.5 years, range 19-36 years) and a baseline horizontal fixation disparity was measured at a distance of 1 m. Thereafter, fixation disparity was measured with induced monocular astigmatic blur in the right eye, creating an astigmatic error in the amounts of -0.75 and -1.25 in axis 90 and axis 45.It was determined that the differences among full correction and the 4 different types of astigmatic blur were not significant when analyzed as one group (P = 0.5445), nor when separated into groups according to whether the subject had naturally occurring astigmatism or not, (astigmatic group, P = 0.3801; non-astigmatic group, P = 0.5899).Monocular astigmatic blur in the amounts of -0.75 and -1.25 did not have a significant effect on tested subjects with regard to the amount of blur or axis orientation. This low amount of blur is likely within the range of compensation for the subjects, proving that spherical equivalent contact lenses are a viable option for low amounts of astigmatic error.

The aim of this study was to evaluate the accommodation response under both mono- and polychromatic light while varying the amount of spherical aberration. It is thought that chromatic and spherical aberrations are directional cues for the accommodative system and could affect response time, velocity or lag. Spherical aberration is often eliminated in modern contact lenses in order to enhance image quality in the unaccommodated eye. This study was divided into two parts. The first part was done to evaluate the amount of spherical and other Zernike aberrations in the unaccommodated eye when uncorrected and with two types of correction (trial lens and spherical-aberration controlled contact lens) and the second part evaluated the dynamic accommodation responses obtained when wearing each of the corrections under polychromatic and monochromatic conditions. Measurements of accommodation showed no significant differences in time, velocity and lag of accommodation after decreasing the spherical aberration with a contact lens, neither in monochromatic nor polychromatic light. It is unlikely that small to normal changes of spherical aberration in white light or monochromatic mid-spectral light affect directional cues for the accommodative system, not in white light or mid-spectral monochromatic light, since the accommodative response did not show any change.

The aim of the present project was to investigate accommodative behavior in young adults and adolescents fitted with an aspheric multifocal (center distance) contact lens with focus on evaluating whether these lenses can be an alternative treatment for subjects in which a reduced level of blur and thereby accommodation in near vision is aimed at. Twenty normal subjects aged between 21 and 35 years participated in the study. Aberrometry was perfomed using a Zywave™ aberrometer, first on the uncorrected eyes of all subjects, and again while the subjects wore a multifocal contact lens with a +1.00 add. A Shin-Nippon N Vision-K 5001 Autoref-Keratometer was used to measure accommodative response with two different refractive corrections: (1) habitual spectacle correction only, and (2) habitual correction and a aspheric multifocal (center distance) contact lens. Four hours of adaptation to the lens was allowed. The lag when wearing only the habitual spectacles was compared with the lag while wearing both the ha...

The main purpose of this study was to evaluate the vergence adaptive ability in subjects diagnosed with convergence excess (CE) phoria (ie, subjects with an esophoric shift from distance to near but without an intermittent tropia at near). Vergence adaptation was measured at far and near with both base-in and base-out prisms using a “flashed” Maddox rod technique in 20 control subjects and 16 subjects with CE. In addition, accommodative adaptation and the stimulus AC/A and CA/C cross-links were measured. The AC/A and CA/C ratios were found to be high and low, respectively, and accommodative adaptation was found to be reduced in CE subjects as compared with the controls (P

The aim of the present study was to evaluate changes in spherical aberration and their effect on visual quality (visual acuity and contrast sensitivity) in both distance and near with different non-custom-made contact lenses.A wavefront analyser was used to measure the aberrations in each subject's eyes uncorrected and with the contact lenses: a standard lens and two aspherical contact lenses. High-contrast visual acuity at distance was measured with Test-Chart 2000 (100% contrast) and at near with Sloan ETDRS Near Point chart (100% contrast). Low-contrast visual acuity at distance was measured with Test-Chart 2000 (10% contrast) and contrast measurements at near with Mars letter contrast sensitivity chart.Mean spherical aberration was positive for all pupil sizes in the uncorrected eye, residual spherical aberration was close to zero with the standard lens for all pupil sizes, whereas the two aspheric contact lenses over-corrected spherical aberration. The changes in aberration were statistically significant (p0.05) with all lenses. No significant difference could be detected between trial frame correction, spherical and aspherical soft contact lens designs with respect to visual quality. This was the case for both distance and near.The results are in line with previous studies and indicate that non-custom-made spherical aberration control contact lenses have little effect on visual quality as defined in this study.

Reading ability in the elderly means independence, and quality of life. In age-related macular degeneration (AMD), the main deficit is the loss of reading ability. The neovascular form is the leading cause of vision loss in the developed world among people over 50 years of age. With ranibizumab (Lucentis) a drug treatment has become available, but, despite good outcome of visual acuity, patients often report that their reading ability has been affected. We aimed therefor to study reading performance with Tobii Eye Tracker in patients, treated with intravitrial Lucentis. Twenty patients, 15 female and 5 male (range 74 - 98 year), were recruited from St. Erik Eye Hospital. All had, before and after treatment, their reading speed, comprehension, fixations, saccadic eye movements measured while reading two texts with an equal readability rating. For all eye movement parameters, except the number of regressions per word, there was no statistically significant difference when comparing the results from before and after treatment. However, a statistically significant increase in the number of regressions per word after treatment as well as increased visual acuity and comprehension, were found. Reading is fundamental in our society and should be tested in order to fully understand a patient’s complaints; however, an increased VA will not necessarily equal an increased reading ability. The results also show that the Tobii system is suitable for evaluation of reading performance in a clinical setting, and can together with other tests, give valuable information about the patients complains and the outcome of a treatment.

Unstable fixation has been reported to be a common cause of unreliable results in perimetry. The Rarebit Fovea Test (RFT) is a computerised foveal function test that evaluates the 4 x 3 degrees central visual field, using very small test stimuli. To minimise the test time, no fixation control is used. Instead, stable fixation is facilitated by the use of a dynamic fixation target. The aim of the current study was to evaluate fixation stability during a RFT examination by continuous recording of the eye movements.Twelve healthy subjects were enrolled in the study together with two amblyopic subjects. A three-dimensional eye tracker was used to measure eye movements during two test sessions. All subjects went through one session of fixation measurement with stimulus presentation and one session without stimulus presentation. Both sessions lasted approximately 90 seconds.Mean hit rate (MHR) in the whole group was 89.7 per cent. Five out of 14 subjects had abnormal RFT results. There was no significant difference in fixation stability either between the test sessions with and without stimulus presentations (p = 0.79) or between the subjects with abnormal (n = 5) and normal (n = 11) MHR, (p = 0.55).Fixation seems stable during RFT testing, thus the test design and fixation target used in the RFT could be considered adequate, at least in subjects with normal or near normal visual function. Further studies are needed to evaluate how different visual abnormalities will affect fixation stability during RFT testing.

The purpose of this study was to investigate the prevalence of conjunctival and corneal epithelial staining in soft contact lens wearers and to see if staining could be associated with factors such as type of lens worn, wearing time, care system, age, and sex.The records of 338 adapted hydrogel contact lens wearers were examined retrospectively.Conjunctival staining was found to be present in 32.5% of the subjects and corneal staining was found to be present in 19.5% of subjects. None of the subjects had staining above grade 2 using the Cornea and Contact Lens Research Unit scale. Because of the low prevalence of staining, the low grading of staining found and the large variation in refractive power, lens type worn, wearing modality, and solution used statistical analysis for association between staining and different factors could only be performed for the association between sex and staining and between corneal and conjunctival staining. However, no statistical significant association could be demonstrated.Despite the low prevalence of staining the conjunctiva and cornea should be examined carefully in contact lens wearers and prospective wearers because the conjunctival and corneal epithelium serve as protective barriers for the underlying layers of the cornea and conjunctiva. To allow comparison of data obtained in different studies assessing corneal staining, it is recommended that clinicians develop and adopt a universal standard protocol for this measure.

Fitting a prism-ballasted soft toric contact lens unilaterally may potentially induce a vergence error that the subject cannot compensate. In the present study, a prism-ballasted (1.5Delta base down) soft toric contact lens was fitted in the right eye only of 10 subjects with normal binocular vision. The effect on binocular vision was evaluated by measuring vertical phoria adaptation and vertical fixation disparity adaptation. The results show that the vertical vergence error induced was well compensated and fully adapted to. However, care might be needed when fitting these lenses unilaterally in subjects with vertical phoria-related problems.

Background: It is not known how accommodative insufficiency influences reading performance. Methods: Reading eye movements were recorded before and after treatment for accommodative insufficiency in 12 school children (eight to 16 years). During the eight-week treatment period all subjects wore a +1.00 D addition when reading. Results: Large variations in reading patterns were found. Despite successful accommodative treatment (p