SCOTOMAS OF AGE-RELATED MACULAR DEGENERATION DETECTED AND CHARACTERIZED BY MEANS OF A NOVEL THREE-DIMENSIONAL COMPUTER-AUTOMATED VISUAL FIELD TEST

Amsler grid test for detection of advanced glaucoma in Ethiopia

Objective

This study was done to determine the validity of amsler grid test black on white (BOW), as well as white on black (WOB) for identifying central visual field (VF) defects in patients with advanced glaucoma.

Design

Prospective study.

Participants

We prospectively included 100 consecutive eyes of 88 adult patients with advanced glaucoma and 100 eyes of 100 normal individuals. We used a lottery method to choose the side of the eye for the control groups.

Methods

All participants had reliable Humphrey 10–2 Swedish Interactive Threshold Algorithm (SITA) standard VF. Both the BOW and WOB amsler grid tests were done for each group. Sensitivity, specificity, and positive and negative predictive values of the amsler grid scotoma area were calculated with the 10–2 VF as the reference standard.

Results

The mean ± standard deviation (SD) of age and the 10–2 VF mean deviation (MD) of advanced glaucoma eyes were 59.8 ± 11.8 (range 34–84) years and -19.94 ± 9.8(range -34.98–-0.52) respectively. Among 108 eyes with normal 10–2 VF test, 103 had a normal BOW amsler grid test and 5 had an abnormal BOW test. Among 92 eyes with an abnormal 10–2 VF test, 74 had an abnormal and 18 had normal BOW amsler grid test. Sensitivity, specificity, and positive and negative predictive values of the BOW amsler grid test were 80.4%, 95.4%, 93% and 85.1% respectively whereas that of the WOB amsler grid test were 71.7%, 95.4%, 93% and 72.8% respectively.

Conclusion

The sensitivity and specificity of both BOW and WOB amsler grid tests were high in detecting VF defects in advanced glaucoma.

Quantifying Visual Dysfunction and the Response to Surgery in Macular Pucker

PURPOSE

To measure the effects of macular pucker (MP) on macular structure and quantify function by measuring visual acuity (VA), contrast sensitivity (CS), and distortions. The effects of surgery were quantitatively evaluated using these measures.

DESIGN

Prospective, comparative case series.

PARTICIPANTS

Fifty-three patients with unilateral MP and normal fellow eyes: 24 operated MP subjects, 17 unoperated controls, and 12 reproducibility subjects.

METHODS

Posterior vitreous detachment was diagnosed by ultrasound and ellipsoid zone disruption (EZD) was determined by OCT, which also measured macular thickness and volume. Vision was assessed, by measuring VA (logMAR) and CS (Freiburg acuity contrast testing: Weber index, %W). A visual distortions index (%DI) was calculated using 3-dimensional threshold Amsler grid testing. Comparisons to controls were performed before surgery and at 1, 3, 6, and 12 months after vitrectomy/membrane peel without chromodissection.

MAIN OUTCOME MEASURES

Posterior vitreous detachment (ultrasound), EZD (OCT), macular thickness and volume (OCT), VA (logMAR), CS (%W), distortions (%DI).

RESULTS

Posterior vitreous detachment was present in 90% of MP eyes, but only 50% of fellow eyes (P < 0.001). All structural and functional indices were worse (28% to 5-fold) in the 24 operated MP eyes than the 17 unoperated MP eyes (P < 0.001). Before surgery, EZD was present in 33% of operated MP eyes but none of the unoperated MP eyes (P < 0.02). The macula was thicker (514±85 μm vs. 257±59 μm; P < 0.001) with greater volume (3.22±0.56 μl vs. 2.14±0.22 μl; P < 0.001) in operated MP eyes than normal fellow eyes. Before surgery, MP eyes had VA = 0.53 logMAR (Snellen equivalent, 20/67) vs. controls = 0.21 (20/32); P < 0.001; CS was 8.61±5.36 %W vs. controls = 3.71±1.47 %W (P < 0.001); and distortions were 7.61±12.6 %DI vs. controls = 0.13±0.61 %DI (P < 0.001). EZD was associated with worse VA (P < 0.01) and CS (P < 0.03) before and after surgery. Each outcome measure improved progressively at 1, 3, 6, and 12 months after surgery, but only %DI and macular volume normalized.

CONCLUSIONS

These quantitative measures characterize the impact of MP on macular structure and function. All indices improved after surgery, but only distortions and macular volume normalized. Contrast sensitivity measurements and quantification of distortions can objectively assess visual dysfunction in MP and may be useful outcome measures of therapy.

[Efficacy of conservative treatment in patients with dry form of age-related macular degeneration]

AIM

To evaluate the efficacy of conservative treatment in dry AMD patients by means of 3D computer-automated threshold Amsler grid testing (3D-CTAG; Fink & Sadun, 2004).

MATERIAL AND METHODS

The study included 90 patients (180 eyes) with dry AMD divided into three groups. Group 1 (n = 30) was prescribed Vitrum Vision forte, 1 tablet b.i.d., group 2 (n = 30)--Vitrum Vision forte, 1 tablet b.i.d. and Vitrum Cardio Omega-3, 1 capsule b.i.d. Group 3 (n = 30), the controls, received Taurine 250 mg, 1 tablet b.i.d. Besides standard ophthalmic examination, all patients underwent 3D-CTAG before and after the treatment. The number of defects per eye (ND) and volume lost relative to the hill-of-vision (VLRH) were chosen as evaluation criteria.

RESULTS

After 3 months of treatment ND decreased from 0.33 ± 0.02 to 0.22 ± 0.01 in group 1 (p < 0.01) and from 0.33 ± 0.02 to 0.2 ± 0.01 in group 2 (p < 0.01); VLRH decreased from 0.32 ± 0.02% to 0.15 ± 0.01% out of 693,000 [deg2%] in group 1 (p < 0.01) and from 0.32 ± 0.03% to 0.15 ± 0.01% out of 693,000 [deg2%] in group 2 (p < 0.01). In the controls both indices increased: ND from 0.32 ± 0.02 to 0.37 ± 0.02 and VLRH from 0.35 ± 0.24% to 0.49 ± 0.03% out of 693,000 [deg2%] (p < 0.01).

CONCLUSION

The positive effect of Vitrum Vision forte in combination with Vitrum Cardio Omega-3 on macular function is comparable to that of monotherapy with Vitrum Vision forte. The maximum effect was achieved in patients with small scotomas (VLRH < 1.5% out of 693,000 [deg2%]).

Strategies for improving early detection and diagnosis of neovascular age-related macular degeneration

Treatment of the neovascular form of age-related macular degeneration (AMD) has been revolutionized by the introduction of such agents as ranibizumab, bevacizumab, and aflibercept. As a result, the incidence of legal blindness occurring secondary to AMD has fallen dramatically in recent years in many countries. While these agents have undoubtedly been successful in reducing visual impairment and blindness, patients with neovascular AMD typically lose some vision over time, and often lose the ability to read, drive, or perform other important activities of daily living. Efforts are therefore under way to develop strategies that allow for earlier detection and treatment of this disease. In this review, we begin by providing an overview of the rationale for, and the benefits of, early detection and treatment of neovascular AMD. To achieve this, we begin by providing an overview of the pathophysiology and natural history of choroidal neovascularization, before reviewing the evidence from both clinical trials and “real-world” outcome studies. We continue by highlighting an area that is often overlooked: the importance of patient education and awareness for early AMD detection. We conclude the review by reviewing an array of both established and emerging technologies for early detection of choroidal neovascularization, ranging from Amsler chart testing, to hyperacuity testing, to advanced imaging techniques, such as optical coherence tomography.

Prospective three-dimensional analysis of structure and function in vitreomacular adhesion cured by pharmacologic vitreolysis

PURPOSE

To prospectively characterize macular structure and function as assessed by combined three-dimensional spectral-domain optical coherence tomography and scanning laser ophthalmoscopy and 3D computer-automated threshold Amsler grid, respectively, in a patient undergoing pharmacologic vitreolysis for vitreomacular adhesion with tractional cysts.

METHODS

Combined 3D optical coherence tomography and scanning laser ophthalmoscopy measured macular volume and 3D computer-automated threshold Amsler grid quantified central visual field function by determining the absolute percent magnitude lost (cumulative value of total visual field loss over all tested levels) before and for a period of 6 months after pharmacologic vitreolysis for vitreomacular adhesion with a single intravitreal injection of microplasmin (125 μg; ThromboGenics).

RESULTS

Ocriplasmin pharmacologic vitreolysis released vitreomacular adhesion by 2 weeks and decreased macular volume from 0.32 μL to 0.15 μL by 1 year after injection. There was a concomitant 4-fold improvement in visual function as measured by 3D computer-automated threshold Amsler grid (percent of central visual field lost) and Snellen visual acuity improved from 20/200 to 20/40.

CONCLUSION

For assessing macular function improvement in conjunction with structural reintegration after pharmacologic vitreolysis for vitreomacular adhesion, 3D computer-automated threshold Amsler grid is a useful tool. Both 3D measurements quantitatively characterized the resolution of this patient's vitreomacular adhesion, suggesting that this is a useful approach to quantifying macular structure and function as indices of the severity of disease and the response to therapy.

Abnormalities of the optic disc

The optic disc represents the anterior end of the optic nerve, the most forward extension of the central nervous system (CNS). The optic disc gives a rare glimpse into the CNS. Hence, diseases of the CNS are often manifested on fundus examination. Abnormalities of the optic disc may reflect eye disease (such as glaucoma), problems in development (as in various syndromes), or CNS disease (such as increased intracranial pressure). Each optic nerve is composed of about 1.2 million axons deriving from the retinal ganglion cells of one eye. Optic atrophy is a morphological sequela reflecting the loss of many or all of these axons. Myriad diseases such as hereditary, metabolic, tumor, and increased intracranial pressure can lead to optic atrophy. Some diseases, such as optic disc drusen, intracranial masses, orbital tumors, ischemic optic neuropathies, inflammations, and infiltrations, can produce optic disc edema before leading to optic atrophy. A number of new imaging modalities, such as optical coherence tomography (OCT), quantitate the thickness of the peripapillary retinal nerve fiber layer as an indirect measure of axonal loss or swelling. OCT can therefore be used to quantitate pathology or the response to therapy in various generalized CNS conditions, such as multiple sclerosis.

Neovascular AMD: an overlooked risk factor for injurious falls

While those with neovascular age-related macular degeneration (NV-AMD) may be at increased risk of injurious falls risk due to poor central vision and suboptimal responses when falling, preserved peripheral vision and decreased activity levels may actually be protective. Compared with control participants, patients with NV-AMD had a significantly greater number of falls and almost twice the risk of injurious falls.

INTRODUCTION

Impaired vision, particularly peripheral visual function, is a key risk factor for injurious falls. NV-AMD is a leading cause of severely impaired vision among older adults but is associated with a profound central, rather than peripheral, deficit. The objective was to determine whether older women with NV-AMD are at an increased risk of falls or injurious falls.

METHODS

We conducted a 12-month prospective cohort study of community-dwelling older (>or=70 years) women, enrolling 114 with NV-AMD and 132 without from a retinal clinic in Vancouver, Canada. Fall incidence was determined through monthly telephone follow-up, with fall severity classified by a blinded reviewer. We compared mean injurious falls per person-year between groups using negative binomial regression.

RESULTS

A mean of 0.37 injurious falls per person-year were experienced among NV-AMD participants, compared to 0.16 injurious falls per person-year among non-NV-AMD participants (p = 0.006). The age-adjusted incidence rate ratio for injurious falls, for an individual with NV-AMD compared to without, was 1.77 (1.07-3.02).

CONCLUSIONS

Older women with NV-AMD are at almost twice the risk of injurious falls compared to those without. Clinicians caring for older adults should recognise NV-AMD as an important risk factor for injurious falls.

Macular function surveillance revisited

BACKGROUND

The Amsler grid is a widely used means of evaluating the central 20 degrees diameter visual field. It is a common practice to have patients who are at risk for exudative maculopathy evaluate their macular function daily using the Amsler grid. The goal is to make the patient aware of the earliest symptoms of choroidal neovascularization at a time when therapeutic intervention has the greatest chance for success. There are, however, several important shortcomings of self-monitoring macular function with the Amsler grid, including low sensitivity and low compliance.

METHODS

The history of macular function surveillance is reviewed. The following techniques that are either currently available or under development for home self-monitoring of macular function are discussed: Amsler grid, red Amsler grid, threshold Amsler grid, environmental Amsler techniques, entoptic perimetry, preferential hyperacuity perimetry, and Internet-based interventions.

CONCLUSION

There is compelling evidence that several currently available technologies are superior to the conventional Amsler grid in detecting the earliest symptoms of macular disease. Threshold Amsler grid, entoptic perimetry, and preferential hyperacuity perimetry each have been found to be more sensitive than the conventional Amsler grid in detecting vision disturbances caused by macular disease. Any one of these diagnostic tests could conceivably be utilized by patients at home for self-monitoring of macular function if the technology were suitably deployed for this purpose, such as over the Internet.

Recent progress in macular function self-assessment

BACKGROUND

Patients that are deemed to be at risk for the development of choroidal neovascularization are frequently instructed to self-monitor their vision for symptoms that may signal the presence of choroidal neovascularization. Traditionally, the Amsler grid has been used for this purpose, but recent technological innovations have resulted in a number of potential alternatives that offer important advantages, including greater sensitivity, the ability to differentiate exudative from non-exudative disease, and quantitative analysis of test results.

METHODS

The following technologies that could be employed for patient self-assessment of macular function in a home setting are reviewed: computerized Amsler grid, preferential hyperacuity perimetry, macular mapping test and noise-field campimetry.

CONCLUSIONS

A number of technologies are currently available that could significantly improve the ability of patients at risk for the development of choroidal neovascularization to self-monitor their central visual field.

Early detection of glaucoma by means of a novel 3D computer-automated visual field test

PURPOSE

A recently devised 3D computer-automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry.

PATIENTS AND METHODS

Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup-to-disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer-automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5-minute test required that the patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30-2 or 24-2).

RESULTS

In this pilot study 79% of the eyes tested in the glaucoma-suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group.

CONCLUSIONS

The 3D computer-automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma.