Magnification Requirement Research Articles

Design of a catadioptric mid-wave infrared telecentric microscope with high numerical aperture and long working distance

Infrared microscopy is widely used in the field of thermal analysis. This paper proposes a design method for a catadioptric mid-wave infrared telecentric microscope system that solves the problem of traditional microscopy systems being unable to simultaneously meet high numerical aperture, long working distance and large magnification requirements. The system is composed of a microscope objective and a tubelens. The objective uses an improved Schwarzschild structure and is connected to the tubelens through an externally located pupil. The system works in the wavelength range of 3.7 μm–4.8 μm, achieves a 0.82 numerical aperture, a 15.5 mm working distance, an 8× magnification and a 2.75 μm object-side resolution. The image size of the detector is 17um, and the MTF of the microscope system at the detector cutoff frequency is greater than 0.2, which is close to the diffraction limit. Finally, tolerance analysis and athermal analysis are conducted on the system, and the results indicate that the system possesses good manufacturability and thermal stability.

Low vision aids provision in an urban setting in Germany between 2014 and 2017: a regional population based study with healthcare claims data

PurposeLittle is known about the utilization of low vision services (LVS) in Germany. To understand which persons and how often these services would be utilized, this study aimed to investigate low vision aids (LVAs) provision in an urban setting and to describe user characteristics and trends in their characteristics.MethodsA retrospective study based on a population-based healthcare claims database in Cologne (N = ~ 500,000), Germany. The study population comprised individuals, who were continuously insured at four large statutory health insurers and who redeemed a prescription for visual aids or aids for blindness between January 2014 and December 2017. We examined their socio-demographic and clinical characteristics. Trends in characteristics were examined with logistic and linear regression models over time.ResultsOut of ~ 500,000 persons, 781 unique individuals (~ 0.2%) redeemed an LVA prescription. They were mainly female (68.7%), 60 years or older (75.3%) and had macular degeneration (50.6%) and/or glaucoma (25.9%). In the working-age subgroup, 33.8% were employed. Visual aids were most often prescribed (74.1%) and of all types of LVAs, individuals most commonly redeemed a prescription for magnifiers (35.8%), screen readers (34.3%) and/or canes (17.1%). Of the entire study population, 75.4% received their prescription from an ophthalmologist, 5.3% from a general practitioner and 7.1% from other medical specialists. Significant trends in characteristics of individuals who redeemed an LVA prescription were not found.ConclusionsBetween 2014 and 2017, 781 individuals in Cologne redeemed an LVA prescription. They had characteristics which mostly can be explained by the epidemiology of VI. Results indicate that individuals that redeemed LVAs have a magnification requirement of ≥ 1.5-fold and ≥ 6-fold. Furthermore, next to ophthalmologists, general practitioners and other medical specialists seem to play a role in LVA provision as well, which should be taken into account by policy makers when planning interventions for increasing LVS provision. Our findings provide a starting point to examine LVS provision in Germany.

Design of tilted and decentered anamorphic optical system based on nodal aberration control

This paper proposes a design method for tilted and decentered anamorphic projection optics. In this method, the structure is designed in groups according to the magnification requirements; the anamorphic system section’s primary aberration is analyzed based on vector aberration theory, the tilted and decentered system section’s node behavior is analyzed based on node aberration theory, and spatial ray tracing is used to control the anamorphic optical system’s pupil to be elliptical to realize pupil matching between groups. A mathematical aberration balance and constraint control model is established. The node position is used as an evaluation function such that the node is close to or within the full field, thus controlling the primary aberration for the initial system over the full field. The initial system is constructed with increased optimization potential to satisfy the aberration and structural constraints. The initial structure for the tilted and decentered anamorphic projection optics (βx=1/4,βy=1/8) is constructed with the coma and astigmatism nodes close to or within the full field. The structure is then optimized to achieve a wavefront root-mean-square error for the EUV tilted and decentered anamorphic objective with NA= 0.55 of better than 0.025λ (λ = 13.5 nm).

Further Validation of Comfortable Print Size as a Parameter for Clinical Low-Vision Assessment.

Comfortable print size (CfPS) has been proposed as a clinical alternative to deriving critical print size (CPS) in the assessment of reading function of vision-impaired patients. This study aimed to assess the repeatability of CfPS and to compare assessment duration and values to CPS measures and acuity reserves. Thirty-four adults with vision impairment had their reading function assessed. Two assessments of CfPS were made by asking, "What is the smallest print size that you would find comfortable using?" Reading parameters including CPS were determined using the MNREAD card chart and MNREAD app. CfPS was quicker to assess (mean ± SD, 144 ± 77 seconds) than the MNREAD card (231 ± 177 seconds) or app (285 ± 43 seconds). Within-session repeatability of CfPS showed no significant bias or variation across the functional range and limits of agreement (LoA) of ±0.09 logMAR. CfPS values were 0.10 logMAR larger than card CPS values, but no different from app CPS values, with LoA of ±0.43 to 0.45 logMAR. Acuity reserve (comparing CfPS to card reading acuity) was 1.9:1 on average, with a maximum of 5.0:1. CfPS offers a quick, repeatable, and individualized clinical measure of the print size required for sustained reading that reflects CPS values obtained by more traditional measures. CfPS is an appropriate clinical measure of reading function to use in determining the magnification requirements of vision impaired patients for sustained reading tasks.

Meta-Learning Multi-Scale Radiology Medical Image Super-Resolution

High-resolution medical images have important medical value, but are difficult to obtain directly. Limited by hardware equipment and patient’s physical condition, the resolution of directly acquired medical images is often not high. Therefore, many researchers have thought of using super-resolution algorithms for secondary processing to obtain high-resolution medical images. However, current super-resolution algorithms only work on a single scale, and multiple networks need to be trained when super-resolution images of different scales are needed. This definitely raises the cost of acquiring high-resolution medical images. Thus, we propose a multi-scale super-resolution algorithm using meta-learning. The algorithm combines a meta-learning approach with an enhanced depth of residual super-resolution network to design a meta-upscale module. The meta-upscale module utilizes the weight prediction property of meta-learning and is able to perform the super-resolution task of medical images at any scale. Meanwhile, we design a non-integer mapping relation for super-resolution, which allows the network to be trained under non-integer magnification requirements. Compared to the state-of-the-art single-image super-resolution algorithm on computed tomography images of the pelvic region. The meta-learning multiscale super-resolution algorithm obtained a surpassing of about 2% at a smaller model volume. Testing on different parts proves the high generalizability of our algorithm. Multi-scale super-resolution algorithms using meta-learning can compensate for hardware device defects and reduce secondary harm to patients while obtaining high-resolution medical images. It can be of great use in imaging related fields.

Is patient identification of 'comfortable' print size a useful clinical parameter for low vision reading assessment?

The purpose of this study was to determine what a person with vision loss considers a 'comfortable' print size to read, and examine whether this reflects any of three currently used parameters for identifying print size required for sustained reading tasks: minimum size to achieve maximum reading speed (the critical print size (CPS)); minimum size for functional reading at 80wpm and/or a size that is double the reading acuity (representing an acuity reserve of 2:1). Forty-seven participants entering low vision rehabilitation (mean age 77years, 24 with macular degeneration) were assessed using MNREAD charts to determine reading acuity, maximum reading speed, CPS and the minimum size allowing functional (80wpm) reading. Comfortable print size was assessed by asking participants to identify 'the smallest print size that you would find comfortable using' on the MNREAD chart. There was little difference between comfortable print size and CPS (mean difference 0.05logMAR (SD 0.18); p=0.08, limits of agreement ±0.35logMAR), and no trend for the difference between values to differ across the functional range. Size for functional reading could only be assessed for 41 participants, and the difference between this and comfortable print size varied across the functional range. Comfortable print size was consistently smaller than twice the reading acuity size (mean difference 0.11logMAR (SD 0.17); p<0.001), with an average acuity reserve of 1.74:1. Asking people with visual impairment to identify a print size that is comfortable to read provides a print size similar to the CPS. This can be used as a guide in selecting magnification for sustained reading without having to undertake further analyses. Identification of perceived comfortable print size may offer a time-efficient clinical method of estimating magnification requirements, and be relevant for undertaking effective remote consultations.

Comparing Reading Speeds for Reading Standardized Single Sentences and Paragraphs in Patients with Maculopathy

Introduction: The purpose of this study was to compare reading speeds (RS) of either paragraphs of text or single sentences in patients with maculopathy by investigating the repeatability of RS to decide which text type to use in studies on patients with maculopathy. Methods: RS was measured for standardized texts in 25 participants with a central scotoma due to maculopathy (mean age 77.8 years ± 9.9 SD, mean binocular visual acuity 0.65 logMAR (±0.85 SD), median magnification requirement 3-fold). Reading 3 single sentences taken from the Radner reading charts (sample #1, #2, and #3) of 14 words and reading 3 paragraphs of International Reading Speed Texts (IReST, sample # 3, #6, and #10) with a mean of 132 (±3.2 SD) words, each in German, were compared. The 6 texts were read aloud in random order from a closed-circuit TV system, with size adjusted according to the individual magnification requirement. Reading time was measured by stopwatch, and speed was calculated in correctly read words per minute (wpm). Differences in RS depending on text length (single sentence vs. paragraph) and text sample were calculated by the Bland-Altman analysis. Results: The mean RS showed no significant difference between 2 charts of the same kind (sentences: 93 wpm ± 37 SD; paragraphs: 95 wpm ± 38 SD). RS differences between 2 charts were lower in paragraphs than in single sentences. Highest correlations of RS between all 6 texts existed between the 3 IReST text samples (r = 0.98, 0.98, and 0.98) compared with the 3 Radner sentences (r = 0.89, 0.81, and 0.90). The inter-chart reliability (coefficient of repeatability) was smaller for the paragraphs (12.9 wpm) than for the single sentences (36.4 wpm). Conclusion: In patients with maculopathy, single sentences are well suited for single measurement of RS. For repeated measurements (e.g., monitoring the course of a reading disorder or assessing effects of interventions), paragraphs are preferable because of their lower variability of RS between the paragraphs.

Visual rehabilitation of patients with corneal diseases

BackgroundAlthough most patients with visual impairment due to corneal diseases can be treated successfully with surgery, some require visual rehabilitation to restore reading ability. To evaluate the best LVAs especially in terms of reading speed and characterize this specific patient group we performed a prospective, randomized cross-over trial.MethodsAll 34 patients underwent a detailed examination (slit-lamp, funduscopy, SD-OCT, ETDRS) as screening. Only patients with corneal diseases without other ocular diseases were included. Reading-speed was assessed with International-Reading-Speed-Texts (IReST) consecutively with five different LVAs (low vision aids) during one day in a randomized cross-over design. Corneal haze was quantified with corneal densitometry (Pentacam).ResultsPatients were either visually impaired (n = 28), severely impaired (n = 4) or legally blind (n = 2). Patients read significantly faster with LVAs (p < 0.0001). Fastest reading speed could be achieved with video magnifier (CCTV). Optical magnifier and portable-electronic magnifier enabled significantly lower reading speeds (p < 0.01). In a subgroup of patients (VA < 3/60,n = 6) black background enabled patients to read significantly faster compared to white background (p = 0.03).ConclusionPatients with low magnification requirement can be treated successfully with optical LVAs and portable-electronic magnifiers. More severely afflicted patients need a CCTV. Black background enables fastest reading-speeds, probably due to less blinding. Visual impairment can be estimated with corneal densitometry. Our trial confirms the capability of LVAs to successfully restore the reading ability in patients with corneal diseases, which is a crucial part of visual rehabilitation.Trial registrationThis trial was registered at the German Clinical Trials Register as DRKS00010887 at 09.08.2016.

Effects of home reading training on reading and quality of life in AMD\u2014a randomized and controlled study

BackgroundAge-related macular degeneration (AMD) causes reading impairment, reduced quality of life (QoL), and secondary depression. We have shown that support with magnifying aids improved reading speed (RS), emotional and cognitive status, and QoL. The present study investigates whether additional reading training (RT) (after adapting to appropriate visual aids) can further improve vision rehabilitation.MethodsPatients with dry AMD were randomly assigned to 2 groups. The primary RT group (P-RTG, n = 25) trained with sequentially presented text (RSVP), and the control group (CG, n = 12) performed placebo training (crossword puzzles) and later crossed over to RT, so that altogether 37 participants performed reading training. Patients trained at home on a PC for 6 weeks. RS was assessed during reading printed paragraphs of text aloud. Using a scanning laser ophthalmoscope, we examined fixation stability and preferred retinal locus (PRL) for fixating a cross, as well as PRL and eye movements during reading single words. We assessed emotional status by Montgomery–Åsberg Depression Rating Scale (MADRS), cognitive status by dementia detection test (DemTect) and QoL by Impact of Vision Impairment (IVI) profile. Visual acuity and magnification requirement were examined by standard procedures. All variables were measured before and after placebo training, before and after RT, and after 6 weeks without training (follow-up).ResultsRS improved significantly in the P-RTG during RT, but not in the CG during placebo training. The effect remained stable at follow-up. Fixation performance and eye movement variables did not change. Emotional status (MADRS) improved in P-RTG during RT and showed a significant difference of the change of scores between the 2 groups.Complete IVI scores improved significantly during RT and remained stable.ConclusionThe results indicate that patients with AMD, who already use magnifying aids, benefit from additional RT and that it can contribute in preventing depression and improve QoL.Trial registrationThe study was registered at the German Clinical Trials Register (DRKS00015609).

OPTiM: Optical projection tomography integrated microscope using open-source hardware and software.

We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope’s existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations’ viability.

Ruthenium-106 brachytherapy for thick uveal melanoma: reappraisal of apex and base dose radiation and dose rate.

PurposeTo evaluate the outcomes of ruthenium-106 (106Ru) brachytherapy in terms of radiation parameters in patients with thick uveal melanomas.Material and methodsMedical records of 51 patients with thick (thickness ≥ 7 mm and < 11 mm) uveal melanoma treated with 106Ru brachytherapy during a ten-year period were reviewed. Radiation parameters, tumor regression, best corrected visual acuity (BCVA), and treatment-related complications were assessed.ResultsFifty one eyes of 51 consecutive patients including 25 men and 26 women with a mean age of 50.5 ± 15.2 years were enrolled. Patients were followed for 36.1 ± 26.5 months (mean ± SD). Mean radiation dose to tumor apex and to sclera were 71 (± 19.2) Gy and 1269 (± 168.2) Gy. Radiation dose rates to tumor apex and to sclera were 0.37 (± 0.14) Gy/h and 6.44 (± 1.50) Gy/h. Globe preservation was achieved in 82.4%. Preoperative mean tumor thickness of 8.1 (± 0.9) mm decreased to 4.5 (± 1.6) mm, 3.4 (± 1.4) mm, and 3.0 (± 1.46) mm at 12, 24, and 48 months after brachytherapy (p = 0.03). Four eyes that did not show regression after 6 months of brachytherapy were enucleated. Secondary enucleation was performed in 5 eyes because of tumor recurrence or neovascular glaucoma. Tumor recurrence was evident in 6 (11.8%) patients. Mean Log MAR (magnification requirement) visual acuity declined from 0.75 (± 0.63) to 0.94 (± 0.5) (p = 0.04). Best corrected visual acuity of 20/200 or worse was recorded in 37% of the patients at the time of diagnosis and 61.7% of the patients at last exam (p = 0.04). Non-proliferative and proliferative radiation-induced retinopathy was observed in 20 and 7 eyes.ConclusionsThick uveal melanomas are amenable to 106Ru brachytherapy with less than recommended apex radiation dose and dose rates.

Treatment options for nystagmus

The following surgical procedures were successfully used as treatment of selected symptoms: (i) unilateral recess-resect surgery of the dominant eye in infantile esotropia with latent nystagmus for the relief of abnormal head posture, (ii) Kestenbaum operation of both eyes in infantile nystagmus syndrome with excentric null zone and abnormal head posture, (iii) recess-resect surgery to produce artificial exophoria in infantile nystagmus syndrome. PHARMACOLOGICAL TREATMENT: Depending on the pathophysiology of different types of nystagmus, several drugs were effective in clinical application (off-label use): (i) gabapentin (non-selective GABAergic and anti-glutamatergic effect): up to 2400 mg/d in infantile nystagmus, acquired pendular nystagmus and oculopalatal tremor, (ii) nemantine (anti-glutamatergic effect): dosage up to 40 mg/d in infantile nystagmus, also in acquired pendular nystagmus and oculopalatal tremor, (iii) baclofen (GABA-B-receptor agonist): 3 × 5-10 mg/d in periodic alternating nystagmus and in upbeat nystagmus, (iv) 4-aminopyridine (non-selective blocker of voltage-gated potassium channels): 3 × 5 mg/d or 1-2 × 10 mg Fampridin in downbeat nystagmus and upbeat nystagmus, (v) acetazolamide (carbonic anhydrase inhibitor): in hereditary episodic ataxia type 2. OPTICAL DEVICES: (i) Contact lenses are used in infantile nystagmus in order to overcome negative effects of eye glasses in abnormal head posture, lateral gaze, and higher refractive errors, (ii) spectacle prisms are useful to induce an artificial exophoria (base-out prisms) or to shift an excentric null zone (base in direction of head posture) of infantile nystagmus with abnormal head posture, (iii) low vision aids may be necessary and should be prescribed according to magnification requirements.

Regularized virtual fields method for mechanical properties identification of composite materials

This paper presents a new material parameters identification method based on the Virtual Fields Method (VFM) where a regularization term coming from a micromechanical model has been added. In this Regularized Virtual Fields Method (RVFM), the system of equations associated to the VFM is solved within a constrained optimization framework. The method was applied to virtual Scanning Electron Microscope in-situ tests aiming at determining the local properties of uni-directional composites loaded in the transverse direction and for which the strain fields were obtained through Digital Image Correlation (DIC). The method was tested for composites with various volume fractions and properties contrasts and under different boundary conditions. The potentials and limitations of the algorithm in the presence of noisy images were investigated and compared to that of the VFM and the other finite element based methods. The corresponding results indicate that the proposed RVFM is more efficient than the other identification techniques in terms of both accuracy and computational time. An optimum size of region of interest was also determined by taking into account DIC magnification requirements and based on the accuracy of the identified parameters. This kind of study can be very useful for determining, a priori, the level of resolution in the imaging system required for a favorable accuracy of the identified parameters.

Design Calculation of Micro-Displacement Amplifier Mechanism Based on Bridge Flexure Hinge

According to the microstructure characteristics of the optical components surface, the paper designs a bridge right-angle flexure hinge driven by a piezoelectric ceramic. It meets the driving micro-displacement magnification requirements and solves the coupling problem in work. Using the calculation formulas of statics and calculation formula of bending moment, the thesis explores the motion law of piezoelectric ceramics with 1KHZ excitation frequency. Through the exploration of the factors of bridge flexure hinge angle stiffness and tensile stiffness, the mathematical model of input displacement and output displacement is established. Studying the theory about the elimination of motion process coupling, it excavates the function relationships of flexure hinge angle and magnification. And the relationship is unearthed among driving force of piezoelectric ceramic, the flexure hinge stiffness, cutting force and mass of cutter system. The paper establishes their mathematical model between the above elements and the output micro-displacement, and the theoretical result is calculated by Matlab. Finally, using Pro/Engineer 3D digital modeling and analysis of simulation results by Ansys, it is found that the error can be controlled in an acceptable range by comparing the theoretical results with simulation results. Through the above analysis, the theoretical design is found to be reliable and effective.

X-ray phase contrast imaging based on three-block multilevel zone plate interferometer

A new scheme of X-ray phase contrast imaging, based on the previously suggested three-block interferometer composed by multilevel Fresnel zone plates, is considered. Two significant features, namely, image optical magnification and low requirements on the spatial and temporal coherency of incident radiation are combined in this scheme.

Design of an in-line, digital holographic imaging system for airborne measurement of clouds

We discuss the design and performance of an airborne (underwing) in-line digital holographic imaging system developed for characterizing atmospheric cloud water droplets and ice particles in situ. The airborne environment constrained the design space to the simple optical layout that in-line non-beam-splitting holography affords. The desired measurement required the largest possible sample volume in which the smallest desired particle size (∼5 μm) could still be resolved, and consequently the magnification requirement was driven by the pixel size of the camera and this particle size. The resulting design was a seven-element, double-telecentric, high-precision optical imaging system used to relay and magnify a hologram onto a CCD surface. The system was designed to preserve performance and high resolution over a wide temperature range. Details of the optical design and construction are given. Experimental results demonstrate that the system is capable of recording holograms that can be reconstructed with resolution of better than 6.5 μm within a 15 cm(3) sample volume.

Training to improve reading speed in patients with juvenile macular dystrophy: a randomized study comparing two training methods

In this study, we examined the clinical application of two training methods for optimizing reading ability in patients with juvenile macular dystrophy with established eccentric preferred retinal locus and optimal use of low-vision aids. This randomized study included 36 patients with juvenile macular dystrophy (35 with Stargardt's disease and one with Best's disease). All patients have been using individually optimized low-vision aids. After careful ophthalmological examination, patients were randomized into two groups: Group 1: Training to read during rapid serial visual presentation (RSVP) with elimination of eye movements as far as possible (n = 20); Group 2: Training to optimize reading eye movements (SM, sensomotoric training) (n = 16). Only patients with magnification requirement up to sixfold were included in the study. Training was performed for 4 weeks with an intensity of ½ hr per day and 5 days a week. Reading speed during page reading was measured before and after training. Eye movements during silent reading were recorded before and after training using a video eye tracker in 11 patients (five patients of SM and six of RSVP training group) and using an infrared reflection system in five patients (three patients from the SM and two patients of RSVP training group). Age, visual acuity and magnification requirement did not differ significantly between the two groups. The median reading speed was 83 words per minute (wpm) (interquartile range 74-105 wpm) in the RSVP training group and 102 (interquartile range 63-126 wpm) in the SM group before training and increased significantly to 104 (interquartile range 81-124 wpm) and 122, respectively (interquartile range 102-137 wpm; p = 0.01 and 0.006) after training, i.e. patients with RSVP training increased their reading speed by a median of 21 wpm, while it was 20 wpm in the SM group. There were individual patients, who benefited strongly from the training. Eye movement recordings before and after training showed that in the RSVP group, increasing reading speed correlated with decreasing fixation duration (r = -0.75, p = 0.03), whereas in the SM group, increasing reading speed correlated with a decreasing number of forward saccades (r = -0.9, p = 0.01). Although the median effect of both training methods was limited, individual patients benefited well. Our results may indicate a difference in the training effect between both methods on the reading strategy: the RSVP method reduces fixation duration, the SM method decreases the number of forward saccades. Patients can apply their newly learned reading strategy in the natural reading situation, e.g. in page reading without special presentation of the text. These results can be used as a basis for further improvement in training methods for optimizing reading performance in patients with a central scotoma.

Improvement of reading speed after providing of low vision aids in patients with age‐related macular degeneration

Age-related macular degeneration (AMD) is the most common cause of severe visual impairment, including loss of reading ability, among elderly persons in developed countries. The aim of the present study was to evaluate reading ability before and after providing of appropriate low vision aids. Five hundred and thirty patients with different stages of AMD (age 82 +/- 8 years) were included in this retrospective study. All patients underwent a standardized ophthalmological examination including evaluation of magnification requirement and careful providing of low vision aids. Before and after the provision of low vision aids, reading speed [words per minute (wpm)] was evaluated using standardized reading texts. For the whole group, the average best-corrected distance visual acuity of the better eye was 0.18 +/- 0.15, with 69% of patients having visual acuity of 0.1 (20/200) or better. The mean magnification requirement was 7.4 +/- 6.3-fold (range 2-25). Visual rehabilitation was achieved with optical visual aids in 58% of patients, whereas 42% of patients needed electronically closed-circuit TV systems. Mean reading speed was 20 +/- 33 wpm before and increased significantly to 72 +/- 35 (p < 0.0001) after the provision of low vision aids for the whole group. Between patients with visual acuity < 0.1 and patients with visual acuity of 0.1 or better, there are highly significant differences in reading speed before (0.4 +/- 3.8 versus 20 +/- 28 wpm, p <or= 0.0001) and after providing of visual aids (40 +/- 13 versus 84 +/- 30 wpm, p <or= 0.0001). Patients with severe visual impairment (visual acuity <or= 0.1) showed significantly lower improvement of reading speed compared to patients with visual acuity of 0.1 or better following rehabilitation (p <or= 0.0001). Before providing of low vision aids, only 16% of patients were able to read; in contrast, reading ability was achieved in 94% of patients after the provision of low vision aids for the whole group. Our results indicate the great value of low vision rehabilitation through adequate providing of vision aids for the improvement of reading ability, with a highly significant increase of reading speed without training of eccentric viewing in patients with retained central fixation. The prompt implementation of low vision aids in patients with macular degeneration will help them to maintain and regain their reading ability, which can lead to an increase in independence, communication, mental agility and quality of life.

Effectiveness of Magnifying Low Vision Aids in Patients with Age-Related Macular Degeneration

The aim of the study was to evaluate the influence of magnification requirement on the effectiveness of low vision aids in patients with age-related macular degeneration (AMD). 656 AMD-patients underwent careful administration of low vision aids and were trained to read with prescribed visual aids for at least 30 minutes. Main outcome measures were: magnification requirement, prescribed low vision aids, reading speed [words per minute = wpm] before and after providing of low vision aids. Mean magnification requirement (MR) was 8.0 ± 6.2 fold, 257 patients had a MR up to 3-fold (Grade 1), 101 patients between 4 to 6-fold (Grade 2) and in 298 patients MR was more than 6-fold (Grade 3). The visual rehabilitation was sufficient with optical low-vision aids in 54%. In 44.5% electronic closed-circuit TV systems were necessary. Only 1.5% of the patients needed an electronic reading device. For the whole group, reading speed (wpm) was on average 12 ± 25 without and increased significantly up to 71 ± 33 with visual aids. There are significant differences (p < 0.0001) of reading speed in three magnification grades before (Grade 1, Grade 2, Grade 3: 27 ± 33, 7.4 ± 14, 0.3 ± 3.0) and after rehabilitation (95 ± 28, 72 ± 24, 46 ± 20, respectively). Patients with a lower magnification requirement (up to 6-fold) showed a significantly higher increase of reading speed than patients with higher magnification requirement (> 6-fold) (p < 0.0001). These results provide quantitative data concerning the success of rehabilitation for AMD-patients with regard to magnification requirement. This important option should be considered early in order to help patients maintain their reading ability, independence and mental agility.

Fernvisus und Vergrößerungsbedarf nach Ranibizumab bei Patienten mit feuchter altersbedingter Makuladegeneration

The purpose of this study was to examine the visual outcome by measuring visual acuity (VA) and magnification requirement (MR) in patients with wet AMD after repeated intravitreal injections of ranibizumab. A total of 195 eyes were treated with repeated intravitreal injections of ranibizumab "as needed". VA (Snellen chart) and MR (SZB reading chart) at baseline of 114 eyes with occult or minimally classic lesions, 42 eyes with predominantly classic lesions and 39 with retinal angiomatous proliferations (RAP) were compared at 3 and 6 months after beginning of treatment. The whole group of 195 patients with wet AMD (688 intravitreal injections within 6 months) demonstrated a mean improvement of VA of 0.72 lines after 3 months (p < 0.001) and 1.54 lines after 6 months (p < 0.001) and a mean improvement of MR of 0.59 log units after 3 months (p < 0.001) and 0.73 log units after 6 months (p < 0.001). Mean change in VA after 3 and 6 months demonstrated a significant improvement (p < 0.001 to p < 0.05) for eyes with occult CNV (+ 0.8 /+ 1.6 lines) and RAP (+ 1.2 /+ 1.9 lines) whereas mean improvement in VA for classic CNV (+ 0.02 /+ 0.87 lines) did not reach significance compared to baseline. Comparable results were obtained for the mean change of MR after 3 and 6 months for eyes with occult CNV (+ 0.75 log units/+ 0.92 log units). For eyes with RAP mean improvement of MR was + 0.74 log units after 3 months (p < 0.05) and it was not significant with + 0.8 log units after 6 months (p > 0.05). MR did not show a significant change during follow-up for classic CNV. Apart from eyes with classic CNV, in more than 90 % of the eyes both VA and MR remained stable or improved (loss < 3 lines in VA or deterioration of MR of < 3 log units). Although 45 % of the eyes with predominantly classic CNV had received photodynamic therapies with Verteporfin prior to the intravitreal injections with ranibizumab, MR remained stable in 80 % over 6 months. With repeated injections of ranibizumab "as needed", VA could be improved as well as MR could be lowered in a majority of patients with wet AMD and therefore reading ability could be optimized. Over 6 months the treatment frequency was lower compared to the monthly administration.