Age-related macular degeneration

Measuring image distortions arising from age-related macular degeneration: An Iterative Amsler Grid (IAG)

Metamorphopsia, perceived as distortion of a shape, is experienced in age-related macular degeneration (AMD): straight lines appear to be curved and wavy to AMD patients and some other retinal pathologies. Conventional clinical assessment largely relies on asking patients to identify irregularities in Amsler Grids - a standardized set of equally spaced vertical and horizontal lines. Perceived distortions or gaps in the grid are a sign of macular pathology. Here, we developed an iterative Amsler Grid (IAG) procedure to obtain a quantifiable map of visual deformations. Horizontal and vertical line segments representing metamorphopsia are displayed on a computer screen. Line segments appearing distorted are adjusted by participants using the computer mouse to change their orientation in several iteratively such that they appear straight. Control participants are able to reliably correct deformations that simulate metamorphopsia while maintaining fixation in the center. In a pilot experiment, we attempted to obtain deformation maps from a small number of AMD patients. Whereas some patients with extensive scotomas found this procedure challenging, others were comfortable using the IAG and generating deformation maps corresponding to their subjective reports. This procedure may potentially be used to quantify local distortions and map them reliably in patients with early AMD.

[Differential diagnosis of various types of fluids on the eye fundus in patients with age-related macular degeneration]

Age-related macular degeneration (AMD) is a leading cause of vision loss both worldwide and in Russia. A distinctive feature of the exudative form of AMD is the presence of choroidal neovascularization (CNV) as a result of pathological angiogenesis of the choroid. With the introduction of optical coherence tomography (OCT) - a non-invasive imaging technique - it has become possible to monitor CNV activity. In the development of CNV, OCT can reveal three types of fluid localization: intraretinal fluid (IRF), subretinal fluid, fluid under retinal pigment epithelium (RPE). Exudative IRF is characterized by the presence of round and/or oval space. This type of fluid is characterized by good response to anti-VEGF therapy. Degenerative IRF («cystoid degeneration») is characterized as a small, clearly defined hyporeflective spaces above the area with altered RPE not responding to anti-VEGF therapy. Thus, early diagnosis of AMD and detection of «new activity» after therapy with antivascular endothelial growth factor (anti-VEGF) by comparing distribution of the fluid in SD-OCT are critical to maintaining or restoring the best possible visual acuity in patients with this disease.

Four complement factor H gene polymorphisms in association with AMD: A meta-analysis

AIM

To investigate the possible association between CFH gene polymorphisms -543G>A (rs1410996), A473A (rs2274700), -257C>T (rs3753394), IVS15 (rs1329428) and AMD risk.

METHODS

We searched the published literature in the Medline and Scopus from inception to May 2015. A meta-analysis was performed by the programs RevMan 5.1 and Stata 12.0, and the Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated in fixed or random effect model based on heterogeneity test among studies.

RESULTS

Nineteen studies with a total of 10,676 subjects were included in the present meta-analysis. A statistical significant association was observed between AMD risk and CFH -543G>A polymorphism with OR of 1.77 (95% CI, 1.47-2.12), 2.24 (95% CI, 1.71-2.94), 0.49 (95% CI, 0.38-0.62) and 0.25 (95% CI, 0.18-0.37) in additive, dominant, recessive and codominant models, respectively. Similar results were obtained in polymorphisms A473A, -257C>T, IVS15. Furthermore, stratified analysis for ethnicity showed a significantly strong association between -543G>A, A473A polymorphisms and AMD risk.

CONCLUSION

The present meta-analysis suggested that CFH -543G>A, A473A, -257C>T, and IVS15 polymorphisms might be moderately associated with AMD risk. This conclusion warrants confirmation by further studies.

Two week, OCT-based follow-up as guidance for retreatment with ranibizumab for CNV apparently refractory to therapy

PURPOSE

To assess the value of 2-week optical coherence tomography (OCT) follow-up for re-treatment decision-making in patients receiving monthly ranibizumab injections for choroidal neovascular membrane (CNV), which was apparently refractory to treatment.

METHODS

A total of 25 eyes of 25 consecutive patients with refractory CNV were included. Patients were classified as having refractory disease if no visual acuity (VA) change and no change in the pattern of macular fluid was noticed on OCT after at least 3 consecutive monthly injections, excluding the loading doses. Repeat injection was given and reassessment with VA and OCT was undertaken at 2, 4, 8, and 12 weeks.

RESULTS

Complete resolution or marked reduction of macular fluid was noted in 19 patients at 2 weeks (responders). In 18 responders, the fluid increased on 4- and persisted on 8- and 12-week follow-ups, so that further injections were given at these time points. In 6 patients, no significant change was noted at 2 weeks (nonresponders). In all of them, VA and OCT were stable on 4-, 8-, and 12-week follow-ups, without further injections.

CONCLUSIONS

As some patients are responding for at least part of the month, injections may be worth continuing or possibly more frequent injections, tailored to the individual's response, may need to be considered. Alternative therapies such as aflibercept may also need to be considered. In nonresponding eyes, other cytokines except for vascular endothelial growth factor are probably involved in the pathogenesis or such cases may have structural damage that will not respond to therapy.

Tango programme for individuals with age-related macular degeneration

Recent research shows that tango dance is an absorbing and effective strategy to reduce levels of depression, while also increasing well-being. This study investigates the feasibility, acceptability, and adherence to a tango programme for individuals with age-related macular degeneration (ARMD). Depression is closely intertwined with the ARMD diagnosis, since the loss of central vision has a profoundly negative impact on the person’s quality of life. Seventeen participants were randomised to tango dance (1.5 h, 2 times/week for 4 weeks) or wait-list control condition. Demographic questions and Visual Function Questionnaire were taken at pre-test. Self-rated symptoms of depression, self-esteem, and satisfaction-with-life were assessed at pre-test and post-test. Tango group participants showed significant reductions in depression and significantly increased satisfaction-with-life and self-esteem at post-test relative to the controls, and reported physical improvement, including increased balance. Tango dance was demonstrated to be a feasible and positive activity for this population.

Effects of major ozonated autohemotherapy in the treatment of dry age related macular degeneration: a randomized controlled clinical study

AIM

To evaluate the effect of systemic ozonated major autohaemotherapy (O(3)-AHT) in patients affected by dry age related macular degeneration (AMD).

METHODS

This study was a randomized, controlled clinical study. One hundred and forty patients with the diagnosis of AMD in both eyes, with the study eye presenting dry AMD and soft drusen, were randomly assigned in a 1:1 ratio to either receive 27 major ozonated autohemotherapy treatments during 12-month period, or a standardized multi-vitamin therapy. Primary outcome was the change in best corrected visual acuity (mean logMar change) between the baseline and 6 and 12 months, end point of the study. In addition, to investigate the safety of prolonged ozonated autohaemotherapy, we measured the routine haematochemical parameters and biochemical oxidative stress values at baseline and after 12 months treatment time.

RESULTS

The mean baseline best corrected visual acuity in study eyes was 0.36 in the treatment group and 0.38 in the control group (difference not statistically significant). At the primary endpoint, 6 months post-baseline, the mean logMAR change in the treated group improved by 0.1 and the values of the control group at the same time impaired by 0.2 respect to the baseline. Four percent and twenty-five percent of eyes in the group treated with O(3)-AHT gained 1 or more lines after 6 and 12 months respectively compared to 0% in the eyes which received no treatment (P<0.05 at 12 months). None of the treated patients experienced a loss in visual acuity in their study eye at 6 and 12 months, compared to 16% and 40 % of patients in the control group who lost 2 lines or more at 6 months and 12 months respectively (P<0.05 treated vs control group)). Major ozonated autohemotherapy was shown to be safe and well- tolerated by the patients. Moreover, the haematochemical parameters showed a decrease in the Reactive Oxygen Metabolites (300±10.1 UCARR at 12 months compared to a baseline value of 380±10.4 UCARR, P<0.05) and an increase in Biological Antioxidant Potential plasma values (2100±34.8 micromoles/ C vitamin after 12 months compared to the baseline value of 1610±36.2, P<0.05) in the treated patients when compared to the control group. This data suggests that major ozonated autohaemotherapy may exert a role in reducing oxidative stress by endogenously stimulating the production of antioxidant molecules.

CONCLUSION

The results of this study suggests that major ozonated autohaemotherapy could be a safe and effective therapeutic option for high-risk patients with dry AMD, and that a series of such treatments could improve the natural course of AMD.

Visual search with image modification in age-related macular degeneration

PURPOSE

AMD results in loss of central vision and a dependence on low-resolution peripheral vision. While many image enhancement techniques have been proposed, there is a lack of quantitative comparison of the effectiveness of enhancement. We developed a natural visual search task that uses patients' eye movements as a quantitative and functional measure of the efficacy of image modification.

METHODS

Eye movements of 17 patients (mean age = 77 years) with AMD were recorded while they searched for target objects in natural images. Eight different image modification methods were implemented and included manipulations of local image or edge contrast, color, and crowding. In a subsequent task, patients ranked their preference of the image modifications.

RESULTS

Within individual participants, there was no significant difference in search duration or accuracy across eight different image manipulations. When data were collapsed across all image modifications, a multivariate model identified six significant predictors for normalized search duration including scotoma size and acuity, as well as interactions among scotoma size, age, acuity, and contrast (P < 0.05). Additionally, an analysis of image statistics showed no correlation with search performance across all image modifications. Rank ordering of enhancement methods based on participants' preference revealed a trend that participants preferred the least modified images (P < 0.05).

CONCLUSIONS

There was no quantitative effect of image modification on search performance. A better understanding of low- and high-level components of visual search in natural scenes is necessary to improve future attempts at image enhancement for low vision patients. Different search tasks may require alternative image modifications to improve patient functioning and performance.