Additional measures of macular function beyond visual acuity.

PURPOSE: Visual function is a complex process in which external visual stimuli are interpreted. Patients with retinal diseases and prolonged follow-up times may experience changes in their visual function that are not detected by the standard visual acuity measure, as they are a result of other alterations in visual function. With the advancement of different methods to evaluate visual function, additional measurements have become available, and further standardization suggests that some methods may be promising for use in clinical trials or routine clinical practice. The objectives of this article are to review these additional measurements and to provide guidance on their application. METHODS: The Vision Academy's membership of international retinal disease experts reviewed the literature and developed consensus recommendations for the application of additional measures of visual function in routine clinical practice or clinical trials. RESULTS: Measures such as low-luminance visual acuity, contrast sensitivity, retinal fixation and microperimetry, and reading performance are measures which can complement visual acuity measurements to provide an assessment of overall visual function, including impact on patients' quality of life. Measures such as dark adaptation, color vision testing, binocular vision testing, visual recognition testing, and shape discrimination require further optimization and validation before they can be implemented in everyday clinical practice. CONCLUSION: Additional measurements of visual function may help identify patients who could benefit from earlier diagnosis, detection of disease progression, and therapeutic intervention. New and additional functional clinical trial endpoints are required to fully understand the early stages of macular disease, its progression, and the response to treatment.

Evolution of macular atrophy in eyes with neovascular age-related macular degeneration compared to fellow non-neovascular eyes.

PURPOSE: Τo evaluate the evolution of macular atrophy (MA) in patients with neovascular AMD (nAMD), compared with their fellow eyes exhibiting dry AMD (dAMD). METHODS: This retrospective study included 124 patients from three centers treated with anti-VEGF in their nAMD eye and having dAMD in the fellow eye. Patients without MA at baseline were analyzed to study the time to first MA development. Synchronous and unsynchronous time course of MA was also studied. MA was evaluated using near-infrared images, while all available optical coherence tomography (OCT) images were used to confirm the criteria proposed by the Classification of Atrophy Meetings group for complete MA. RESULTS: MA first detection in nAMD eyes increased significantly from year 2 to 6 compared to dAMD eyes. Over the study's follow-up, 45.1% of nAMD-E developed MA, compared to 16.5% of fellow eyes (p < 0.001). When MA in the two eyes was compared in a synchronous paired manner over 4 years, nAMD eyes had an average MA progression rate of 0.275 mm/year versus 0.110 mm/year in their fellow dAMD eyes. Multivariate ANOVA revealed significant time (p < 0.001), eye (p = 0.003), and time-eye interaction (p < 0.001) effects. However, when MA did develop in dAMD eyes and was compared in an asynchronous manner to MA of nAMD eyes, it was found to progress faster in dAMD eyes (dAMD: 0.295 mm/year vs. nAMD: 0.176 mm/year) with a significant time-eye interaction (p = 0.015). CONCLUSIONS: In this study, a significant difference in MA incidence and progression was documented in eyes with nAMD under treatment, compared to fellow eye exhibiting dAMD. Eyes with nAMD tended to develop more MA compared to fellow dAMD eyes. However, when atrophy did develop in the fellow dAMD eyes, it progressed faster over time compared to MA in nAMD eyes.

Efficacy οf Wet Age-related Macular Degeneration Treatment οn Reading: A Pilot Study Using Eye-movement Analysis.

SIGNIFICANCE: Functional vision, as evaluated with silent passage reading speed, improves after anti-vascular endothelial growth factor (anti-VEGF) treatment in patients with wet age-related macular antidegeneration (wAMD), reflecting primarily a concomitant reduction in the number of fixations. Implementing eye movement analysis when reading may better characterize the effectiveness of therapeutic approaches in wAMD. PURPOSE: This study aimed to evaluate silent reading performance by means of eye fixation analysis before and after anti-VEGF treatment in wAMD patients. METHODS: Sixteen wAMD patients who underwent anti-VEGF treatment in one eye and visual acuity (VA) better than 0.5 logMAR served as the AMD group. Twenty adults without ocular pathology served as the control group. Central retinal thickness and near VA were assessed at baseline and 3 to 4 months after their first visit. Reading performance was evaluated using short passages of 0.4-logMAR print size. Eye movements were recorded using EyeLink II video eye tracker. Data analysis included computation of reading speed, fixation duration, number of fixations, and percentage of regressions. Frequency distributions of fixation durations were analyzed with ex-Gaussian fittings. RESULTS: In the AMD group, silent reading speed in the treated eye correlated well with central retinal thickness reduction and improved significantly by an average of 15.9 ± 28.5 words per minute (P = .04). This improvement was accompanied by an average reduction of 0.24 ± 0.38 in fixations per word (P = .03). The corresponding improvement in monocular VA was not statistically significant. Other eye fixation parameters did not change significantly after treatment. No statistically significant differences were found in the control group. CONCLUSIONS: Visual acuity tests may underestimate the potential therapeutic effects after anti-VEGF treatment in patients with relatively good acuity who are being treated for wAMD. Evaluating silent reading performance and eye fixation parameters may better characterize the effectiveness of therapeutic approaches in wAMD patients.

Progression of Macular Atrophy in Patients Receiving Long-Term Anti-VEGF Therapy for Age-Related Macular Degeneration: Real-Life Data.

PURPOSE: This study aimed to evaluate the progression of macular atrophy (MA) based on near-infrared reflectance (NIR) and optical coherence tomography (OCT) images, in patients with age-related macular degeneration (AMD), receiving anti-vascular endothelial growth factor (anti-VEGF) treatment for at least a 6-year period. MATERIALS AND METHODS: This retrospective study included 53 naïve patients (53 eyes) with neovascular AMD from 2 centers, who were treated with anti-VEGF intravitreal injections and had no MA at baseline. MA was evaluated in an annual basis using NIR images, while all available OCT images were used to confirm that the atrophic area fulfilled the criteria proposed by the Classification of Atrophy Meetings (CAM) group for complete retinal pigment epithelium and outer retinal atrophy. Incidence and progression of MA were evaluated. Associations with best-corrected visual acuity (BCVA) and total number of injections were also studied. RESULTS: Treatment duration of our patients was 7.34 ± 1.54 years. The mean number of anti-VEGF injections was 24.4 ± 13.6. BCVA at baseline was 0.38 ± 0.27 logMAR, while at the final visit, it was 0.60 ± 0.35 logMAR (p = 0.731). The cumulative incidence of new MA at years 1, 2, 3, 4, 5, and 6 was 1.89%, 18.87%, 32.08%, 39.62%, 49.06%, and 50.94%, respectively. In patients who developed MA, mean MA area increased from zero at baseline to 5.66 ± 7.18 mm2 at the final visit. The estimated annual enlargement of MA was 0.45 mm/year based on square root transformation (1.12 mm2/year, untransformed data). MA progression does not appear to be significantly associated with age (R = 0.055; p = 0.784), gender (R = 0.113; p = 0.576), BCVA (R = 0.168; p = 0.404), and total number of injections (R = 0.133; p = 0.255). CONCLUSION: In this real-life setting, half of the neovascular AMD patients under anti-VEGF treatment, without MA at therapy initiation, developed MA over a period of at least 6 years. In this work, the number of injections did not seem to have a significant association with MA progression.

Isolated and Syndromic Retinal Dystrophy Caused by Biallelic Mutations in RCBTB1, a Gene Implicated in Ubiquitination.

Inherited retinal dystrophies (iRDs) are a group of genetically and clinically heterogeneous conditions resulting from mutations in over 250 genes. Here, homozygosity mapping and whole-exome sequencing (WES) in a consanguineous family revealed a homozygous missense mutation, c.973C>T (p.His325Tyr), in RCBTB1. In affected individuals, it was found to segregate with retinitis pigmentosa (RP), goiter, primary ovarian insufficiency, and mild intellectual disability. Subsequent analysis of WES data in different cohorts uncovered four additional homozygous missense mutations in five unrelated families in whom iRD segregates with or without syndromic features. Ocular phenotypes ranged from typical RP starting in the second decade to chorioretinal dystrophy with a later age of onset. The five missense mutations affect highly conserved residues either in the sixth repeat of the RCC1 domain or in the BTB1 domain. A founder haplotype was identified for mutation c.919G>A (p.Val307Met), occurring in two families of Mediterranean origin. We showed ubiquitous mRNA expression of RCBTB1 and demonstrated predominant RCBTB1 localization in human inner retina. RCBTB1 was very recently shown to be involved in ubiquitination, more specifically as a CUL3 substrate adaptor. Therefore, the effect on different components of the CUL3 and NFE2L2 (NRF2) pathway was assessed in affected individuals' lymphocytes, revealing decreased mRNA expression of NFE2L2 and several NFE2L2 target genes. In conclusion, our study puts forward mutations in RCBTB1 as a cause of autosomal-recessive non-syndromic and syndromic iRD. Finally, our data support a role for impaired ubiquitination in the pathogenetic mechanism of RCBTB1 mutations.

Mutations in CEP78 Cause Cone-Rod Dystrophy and Hearing Loss Associated with Primary-Cilia Defects.

Cone-rod degeneration (CRD) belongs to the disease spectrum of retinal degenerations, a group of hereditary disorders characterized by an extreme clinical and genetic heterogeneity. It mainly differentiates from other retinal dystrophies, and in particular from the more frequent disease retinitis pigmentosa, because cone photoreceptors degenerate at a higher rate than rod photoreceptors, causing severe deficiency of central vision. After exome analysis of a cohort of individuals with CRD, we identified biallelic mutations in the orphan gene CEP78 in three subjects from two families: one from Greece and another from Sweden. The Greek subject, from the island of Crete, was homozygous for the c.499+1G>T (IVS3+1G>T) mutation in intron 3. The Swedish subjects, two siblings, were compound heterozygotes for the nearby mutation c.499+5G>A (IVS3+5G>A) and for the frameshift-causing variant c.633delC (p.Trp212Glyfs(∗)18). In addition to CRD, these three individuals had hearing loss or hearing deficit. Immunostaining highlighted the presence of CEP78 in the inner segments of retinal photoreceptors, predominantly of cones, and at the base of the primary cilium of fibroblasts. Interaction studies also showed that CEP78 binds to FAM161A, another ciliary protein associated with retinal degeneration. Finally, analysis of skin fibroblasts derived from affected individuals revealed abnormal ciliary morphology, as compared to that of control cells. Altogether, our data strongly suggest that mutations in CEP78 cause a previously undescribed clinical entity of a ciliary nature characterized by blindness and deafness but clearly distinct from Usher syndrome, a condition for which visual impairment is due to retinitis pigmentosa.

Assessing Variability in Reading Performance with the New Greek Standardized Reading Speed Texts (IReST).

SIGNIFICANCE: This article evaluates the standardized Greek version of the International Reading Speed Texts (IReST) set, which enriches interlanguage comparisons and international clinical studies of reading performance. Moreover, it investigates how specific textual and subject-related characteristics modulate the variability of reading speed across texts and readers. PURPOSE: The purpose of this study was to develop a standardized Greek version of the IReST set and investigate how specific textual and subject-related factors modulate the variability of reading speed across texts and readers. METHODS: The English IReST texts were translated to Greek and matched for length, content, and linguistic difficulty. The Greek IReSTs were presented at a distance of 40 cm and size of 1 M to assess reading speeds of 25 normally sighted native speakers (age range, 18 to 35 years). The participants read the texts aloud while reading time was measured by stopwatch. Reading performance included measurement of reading speed in three units of analysis. Reading efficiency was assessed using a word-level oral reading task. Statistical analysis included evaluation of subject- and text-related variability, as well as correlations between reading speed and specific textual and subject-related factors. RESULTS: The average reading speed between texts was 208 ± 24 words/min, 450 ± 24 syllables/min, and 1049 ± 105 characters/min. Differences between readers accounted for the 76.6%, whereas differences across texts accounted for the 23.4% of the total variability of reading speed. Word length (in syllables per word) and median word frequency showed a statistically significant contribution to the variability of reading speed (r = 0.95 and 0.70, respectively). Reading speed was also statistically correlated with word reading efficiency (r = 0.68). CONCLUSIONS: The addition of the Greek version in the IReST language pack is expected to be a valuable tool for clinical practice and research, enriching interlanguage comparisons and international studies of reading performance.

Photoacoustic imaging methodology for the optical characterization of contact lenses.

We demonstrate photoacoustic microscopy as a metrology method for the optical characterization and quality control of contact lenses (CLs). Dual-wavelength excitation is applied to CLs tinted on both sides with two thin ink layers, each of them possessing distinctly different optical absorption properties. Thus, the method is capable of measuring the elevation maps of both CL surfaces during two subsequent imaging sessions and extracting the CL thickness, curvatures, and dioptric power. We show that such an easily implementable technique provides robust, high-precision, cost-effective three-dimensional imaging and characterization of both rigid and soft CLs, which renders it highly favorable for a broad range of applications.

Pharmacokinetics and efficacy of intraocular flurbiprofen.

PURPOSE: Intravitreal delivery of non-steroidal anti-inflammatory drugs could be an effective way to treat macular edema caused by posterior segment inflammation. In this study, we evaluated the intravitreal bioavailability and anti-inflammatory efficacy of flurbiprofen in rabbit eyes. METHODS: For pharmacokinetics, 0.1 ml of 7.66 mg/ml flurbiprofen solution was injected intravitreally and vitreous drug levels were analyzed at specific time points using LC-MS technique. For efficacy, 100 ng lipopolysaccharide of E.coli was injected intravitreally in rabbits to induce inflammation. The animals were separated in three groups and received intraocular flurbiprofen, dexamethasone and PBS to serve as control. Complete ocular examination and total cell count in aqueous fluid were determined to evaluate the extent of inflammation. Eyes were then enucleated for histopathology analysis. The efficacy in the uveitis model was determined by clinical signs of inflammation, total leukocyte count and histology findings. RESULTS: No adverse events were observed during pharmacokinetic assessment. No signs of inflammation, hemorrhage or retina detachment were detected. The recovery of flurbiprofen from vitreous samples was 92.6%. The half-life of flurbiprofen was estimated to be 1.92 h with an elimination constant rate (K) of 0.36. Treatment with intraocular injections of flurbiprofen and dexamethasone significantly reduced total leukocyte count in a manner comparable to dexamethasone [reduction of 96.84% (p < 0.05) and 97.44% (p < 0.05), respectively]. Histologic studies demonstrated significantly less signs of ocular inflammation after flurbiprofen injection compared to control eyes. CONCLUSIONS: Flurbiprofen is effective in suppressing inflammation in this experimental uveitis model. In our experimental setting, intravitreal flurbiprofen seem to have a therapeutic result comparable to dexamethasone. However, the half-life of the drug remains short, necessitating further research to prolong its presence in the vitreous cavity.

Quantification of parafoveal capillary network using a semi-automated algorithm.

OBJECTIVE: The quantification of the morphology of the parafoveal capillary network (PCN) in fluorescein angiography (FA) images using a novel semi-automated computerized method. MATERIAL AND METHODS: Using the MatLab R2011 a software we developed an algorithm that detects automatically the parafoveal capillary bed and its branch points as depicted in FA images creating simultaneously an one-pixel-wide skeleton of it. The detection process starts after delineating manually the foveal avascular zone in a cropped 1500µm*1500µm subimage resulting from the original FA image. Thereafter the algorithm calculates the capillary density and the branch points in a circle area with 1000µm radius. The method was also applied on FA images from subjects without diabetes mellitus, diabetics without diabetic retinopathy (DR) signs, patients with non-proliferative DR and patients with proliferative DR in order to assess the PCN morphology metrics for the studied groups. RESULTS: The PCN density and the parafoveal capillary branch points were estimated for the mentioned subject groups and any significant differences among them were assessed as well. CONCLUSIONS: The described method could serve as a potential tool for the diagnosis and monitoring of PCN diseases and subclinical abnormalities. The assessed metrics reflect the capillary abnormalities in the central 1000µm area across different DR stages.

First report of OPA1 screening in Greek patients with autosomal dominant optic atrophy and identification of a previously undescribed OPA1 mutation.

PURPOSE: To describe the genotype-phenotype correlation in four Greek pedigrees with autosomal dominant optic atrophy (ADOA) and OPA1 mutations. METHODS: Seven patients from four unrelated families (F1, F2, F3, F4) were clinically assessed for visual acuity, color vision, ptosis, afferent pupillary defects, and visual fields and underwent orthoptic assessment, slit-lamp biomicroscopy, and fundus examination to establish their clinical status. Genomic DNA was extracted from peripheral blood samples from all participants. The coding region (exons 1-28), including the intron-exon boundaries of the OPA1 gene, was screened in the probands of the four families, as well as in seven additional family members (four affected and three unaffected) with PCR and direct DNA sequencing. RESULTS: All patients presented bilateral decrease in best-corrected visual acuity and temporal pallor of the optic disc. The visual fields of the adult patients showed characteristic scotomata. Other signs were present in some patients such as decreased color discrimination and a gray crescent within the neuroretinal rim. After the OPA1 gene was sequenced, a previously undescribed heterozygous splice-site mutation c.784-1G>T in intron 7 was detected in family F2. In families F1, F3, and F4, a previously reported in-frame deletion c.876_878delTGT/p.(Val294del), the frameshift c.2366delA/p.(Asn789Metfs*11), and splice-site c.1140+5G>C mutations were detected, respectively. CONCLUSIONS: This is the first report of molecular characterization of Greek patients with ADOA. Our findings provide additional information regarding the genotype-phenotype correlation and establish the role of the OPA1 gene in Greek patients with ADOA.

Silicone oil insulation effects on flash electroretinogram and visual evoked potential in patients with retinal detachment.

BACKGROUND: Silicone oil is used as endotamponade following vitreoretinal surgery to maintain the retina reattached when indicated. This study investigates the hypothesis that silicone oil causes insulation effects on the retina by affecting its response to light. METHODS: Electrophysiological responses to a flash stimulus were recorded using full-field electroretinography (ERG) and visual evoked potentials (VEP). Recordings were performed in 9 patients who underwent surgery for retinal detachment, before (1-2 days) and after (2-3 weeks) silicone oil removal (SOR) in both the study and the control eye. Flash ERG and VEP recordings were performed according to the ISCEV standard protocol. RESULTS: Statistically significant differences were found in the study eye in the amplitudes of the ERG responses and their corresponding ratios, i.e. the amplitude after SOR over the amplitude before SOR, in all conditions tested. No differences were observed in the control eye. The mean ratio of photopic ERG response was 3.4 ± 2.4 for the study and 1.0 ± 0.3 for the control eye (p<0.001). The mean ratio of ERG flicker response was 3.1 ± 2.4 and 1.0 ± 0.3, respectively (p = 0.003). Scotopic flash ERG ratio was 5.0 ± 4.4 for the study and 1.3 ± 0.6 for the control eye (p = 0.012). No differences were observed for the amplitude and latency of flash VEP response after SOR. CONCLUSIONS: Silicone oil causes a reduction in flash ERG responses; no effect was found on flash VEP responses. ERGs in eyes filled with silicone oil should not be considered representative of retinal functionality, in contrast to VEPs, which are not affected by silicone oil presence.

A 52-Year-Old Man with Aneurysmal Subarachnoid Hemorrhage Associated with Delayed-Onset Vitreous Hemorrhage (Terson's Syndrome) Successfully Treated with Balloon-Assisted Coiling and Delayed Vitrectomy.

BACKGROUND Terson's syndrome (TS) is a medical condition characterized by intraocular bleeding that can lead to visual impairment and is associated to subarachnoid hemorrhage (SAH). The pathophysiology and natural history are not well established in the current literature. This report describes successful treatment of a 52-year-old man with aneurysmal SAH who developed late-onset TS using balloon-assisted coiling and vitrectomy to raise awareness of this important complication of aneurysmal SAH. CASE REPORT A 52-year-old smoker with no known past medical history presented to the emergency department with a sudden, severe headache that worsened with photophobia and phonophobia. The patient had a diffuse SAH and underwent an embolization procedure. After 48 hours of close Intensive Care Unit monitoring, the patient's vital signs were stable, and the GCS score was consistently 15/15. However, after 3 weeks in the hospital, the patient experienced blurred vision and a right upper quadrantanopia. Further examination revealed TS and the patient underwent a vitrectomy in 1 eye. The surgery was successful and the eye recovered to 20/20 with no complications. However, the other eye showed slow absorption of the hemorrhage, and a vitrectomy was scheduled for that eye as well. CONCLUSIONS TS is a complication of aneurysmal SAH that can lead to vision loss and increased morbidity. It often goes undiagnosed, and ophthalmologists are not regularly consulted. Late manifestation of the condition is exemplified by the present case. Early detection and intervention are crucial for better patient outcomes.

Xerophthalmia and acquired night blindness in a patient with a history of gastrointestinal neoplasia and normal serum vitamin A levels.

A 69-year-old male patient presented to our department with a 3-month history of nyctalopia. Reviewing of his general health revealed a history of gastrointestinal tumor treated with a modified WHIPPLE operation. Ocular findings at presentation included mild xerophthalmic features and nonspecific pigmentary retinal changes. A standard full-field electroretinogram (ERG) was obtained that showed normal photopic function and extinguished scotopic function. The ocular symptoms, the history and the ERG findings suggested vitamin A deficiency as a possible cause for his complaints. Serum vitamin A levels were subsequently requested, but the results were within normal limits. Despite the normal serum vitamin A levels, the patient was instructed to commence treatment with high doses of oral vitamin A supplements. One month after the onset of the treatment, the patient reported that his visual function has significantly improved, while repeat ERG testing revealed that scotopic function has improved to normal levels. This case highlights that in patients with acquired night blindness due to vitamin A deficiency, the ERG responses possibly represent a more sensitive marker compared to the serum levels of vitamin A.

Effect of panretinal photocoagulation treatment on vision-related quality of life of patients with proliferative diabetic retinopathy.

PURPOSE: To evaluate the effect of laser panretinal photocoagulation for bilateral proliferative diabetic retinopathy on vision-related quality of life. METHODS: In this prospective study, 20 patients (12 men and 8 women) with bilateral proliferative diabetic retinopathy treated with panretinal photocoagulation were included (mean age: 65 years, SD: 11.6 years). On average, patients received 2,140 laser spots per eye. The National Eye Institute 25-Item Visual Function Questionnaire (VFQ-25) was used to evaluate patients' vision-related quality of life. The VFQ-25 was filled in by interview twice, at the beginning and at least 1 month after the completion of panretinal photocoagulation. Comparison of preoperative and postoperative VFQ-25 composite and subscale scores was performed. Correlation was evaluated between change in composite score and treatment intensity as indicated by mean number in laser spots. RESULTS: Mean composite score before laser treatment was 71.9 ± 14.8 and after treatment it was 70.6 ± 17.2 (P = 0.748, paired t-test). None of the subscale scores had a statistically significant difference before and after treatment. Composite score change was not correlated with treatment intensity. CONCLUSION: Panretinal photocoagulation as applied in our study, although destructive in nature, is well tolerated by the patients, without interfering significantly with their quality of life.

Comparison of visual acuity charts in young adults and patients with diabetic retinopathy.

PURPOSE: To compare visual acuity (VA) assessed in healthy eyes and eyes with diabetic retinopathy (DR) using three different logMAR charts: the Sloan letter European-wide chart, the tumbling E chart, and the Landolt C chart. METHODS: Measurements on one eye of 40 volunteers (aged 29 ± 4 years) without visual impairment and 31 DR patients (aged 70 ± 9 years) with mild/moderate visual impairment were included. Visual acuity was assessed, with habitual refractive correction, using each of the three charts. Bland-Altman charts were constructed, and 95% limits of agreement were calculated to measure agreement. RESULTS: Mean VA in the group of young adults was -0.05 ± 0.10 (Sloan letter), -0.02 ± 0.13 (tumbling E), and 0.00 ± 0.12 (Landolt C) logMAR. Average VA estimates differed to a statistically significant extent between all charts. Mean VA in the DR group was 0.46 ± 0.25 (Sloan letter), 0.48 ± 0.26 (tumbling E), and 0.59 ± 0.28 (Landolt C). A statistically significant difference was observed for average Sloan letter versus Landolt C (p < 0.001) and tumbling E versus Landolt C (p < 0.001) acuities. Moreover, in healthy eyes, a moderate correlation (r = -0.38, p = 0.015) was found between the discrepancy in Sloan letter and Landolt C acuity and the mean VA estimate. The 95% limits of agreement were wide (more than approximately 0.2 logMAR for each comparison) and wider in the DR group chart comparisons than in healthy eyes. CONCLUSIONS: Landolt C charts resulted in worse VA estimates compared with letter and tumbling E charts in both young adults and visually impaired subjects with DR. These differences seem more pronounced in DR patients who exhibit worse VAs. The specific study population must be considered in comparing outcomes from different clinical practices.

Contrast sensitivity in the 'good eye' of adult patients with severe impairment in the other eye.

PURPOSE: It is widely accepted that monocular deprivation results in improved visual performance in the non-pathological eye. The current study investigates the effect of deprivation due to severe impairment in one eye during late childhood or adulthood, on the spatial performance of the fellow 'good' eye. METHODS: Twenty patients (age: 29 ± 9 years) with severe visual impairment in one eye (visual acuity equal or worse than count fingers at 1 m), for a period longer than 2 years, participated in the study. Only patients with an age less than 50 years and monocular deprivation onset greater than 9 years were included. On the basis of the time of deprivation the patients were categorised into two subgroups: (i) long-past deprivation (N = 8, age 28 ± 8 years, 9-20 years of deprivation) and recent deprivation (N = 12, age 30 ± 11 years, 2-4 years of deprivation). Eighteen more participants (age: 28 ± 5 years) with normal binocular vision served as the control group. Best-corrected contrast sensitivity was evaluated using reversing (2 Hz) vertical sinusoidal gratings. Seven spatial frequencies (1, 2, 4, 8, 12, 16 and 24 c/deg) were tested. Performance of the control group was tested both monocularly (dominant eye) and binocularly. RESULTS: In normal subjects, binocular viewing improved contrast sensitivity on average by 4.2 dB (corresponding to a 70% improvement in contrast threshold) compared to monocular recordings. Average contrast sensitivity in subjects with impaired vision in one eye was found to be higher by 5.0 dB (corresponding to an 83% improvement in contrast threshold) compared with the dominant eye of the control group. The increase in sensitivity was independent of spatial frequency. No differences were observed between the two subgroups with recent and long-past deprivation. CONCLUSIONS: Notable improvement in contrast sensitivity was found in the non-pathological eye of patients with severe impairment in the other eye at an age after the "critical" period of visual development. These findings are consistent with growing evidence supporting functional changes as a result of altered experience or injury in the adult vision system.

Comparing silent reading performance for single sentences and paragraphs: an eye movement-based analysis.

CLINICAL RELEVANCE: Reading performance in clinical practice is commonly evaluated by reading 'aloud' and 'as fast as possible' single sentences. Assessing comprehensive silent reading performance using passages, composed of multiple sentences, is the preferred reading mode in real-life reading conditions. BACKGROUND: The purpose of this study was to compare eye movement-based silent reading performance for standardised short sentences and paragraphs. METHODS: A group of 15 young volunteers (age range: 22-36 years) read silently and comprehensively in two sessions: (a) a paragraph with continuous text and (b) standardised short sentences. Text print size was 0.4 logMAR (1.0 M at 40 cm distance). Eye movements during reading were recorded using video oculography (EyeLink II, SR Research Ltd). Data analysis included computation of reading speed, fixation duration, the number of fixations, saccadic amplitude and percentage of regressions. Moreover, frequency distributions of fixation durations were analysed with ex-Gaussian fittings. RESULTS: Repeatability coefficient in silent reading speed was found better for the paragraph (66 wpm) than for short sentences (88 wpm). The superiority in repeatability coefficient for the corresponding eye movement parameters, i.e. fixation duration (35 vs 73 ms), regressions (10.1 vs. 22.3%) and fixations per word (0.21 vs. 0.37 fpw), was even more pronounced. In addition, a statistically significant improvement with the paragraph was found in average fixation duration (19 ± 26 ms, p = 0.02), regressions (4.2 ± 7.0%, p = 0.04) and ex-Gaussian fixation parameter, τ (82 vs. 111 ms). No statistically significant difference was found between average reading speed with the paragraph (220 ± 59 wpm) and the short sentences (206 ± 57 wpm) (p = 0.11). DISCUSSION: Due to their superior repeatability, paragraphs are preferable to short sentences when evaluating silent comprehensive reading. The concurrent recording of eye movement parameters in silent reading further improves variability and could offer an efficient measure of reading performance and a reliable biomarker of visuo-motor function.

Posterior Vitreous Detachment and Its Role in the Evolution of Dry to Wet Age Related Macular Degeneration.

Purpose: To examine the state of the posterior vitreous in eyes with exudative age-related macular degeneration, AMD, non-exudative AMD and in normal eyes. Study: This is a prospective, cross-sectional study. Methods: B-scan ultrasonography and Optical Coherence Tomography, OCT were performed in 165 patients older than 65 years with any AMD and in 22 patients older than 65 years with normal eyes in order to diagnose the eyes with complete posterior vitreous detachment, PVD and the eyes with persistent central vitreomacular adhesion, VMA. All patients were selected from the outpatient clinic of the Ophthalmology Department in the University Hospital of Patras. Fundus Fluoroangiography, FFA was used in order to determine the development of exudative AMD from non-exudative AMD. Follow up time was 48 months. Results: 16/171 eyes with exudative AMD (9.36%) had complete PVD, and the rest 155/171 (90.64%) had central VMA. Eleven of 138 eyes with non-exudative AMD (7.97%) had complete PVD and the remaining 127 eyes (92.03%) had central VMA. During the 48 months of the study, 28 eyes, all with central VMA progressed to exudative AMD. Conclusion: Vitreomacular adhesion is associated with both exudative and non-exudative AMD. Progression of the non-exudative eyes to exudative AMD seems to be lower in eyes with complete PVD. On the other hand, the progression of normal eyes to exudative AMD appears to be independent of the posterior vitreous status. Larger and longer studies need to replicate these findings and support the potential of a protective role of complete posterior vitreous detachment in the evolution of the disease.