Three-dimensional computer-automated threshold Amsler grid test

Visual Field Sensitivity Prediction Using Optical Coherence Tomography Analysis in Hydroxychloroquine Toxicity

Purpose

This study investigates the association between local retina structure and visual function in a cohort with long-term hydroxychloroquine (HCQ) use.

Methods

The study included 84 participants (54 participants without toxicity and 30 participants with toxicity) with history of chronic HCQ use (14.5 ± 7.4 years) who had testing with spectral-domain optical coherence tomography (SD-OCT) imaging and Humphrey 10-2 visual fields. Optical coherence tomography (OCT) metrics (total and outer retina thickness [TRT and ORT], minimum intensity [MinI], and ellipsoid zone [EZ] loss) were sampled in regions corresponding to visual field test locations. Univariate linear correlations were investigated and a multivariate random forest regression using a combination of OCT metrics was used to predict visual field sensitivity by locus using a leave-one-out cross-validation strategy.

Results

In univariate linear regression, EZ loss demonstrated the strongest relationship with visual field sensitivities in the parafoveal ring with R2 = 0.58. TRT and ORT revealed positive correlations with visual field sensitivity (R2 = 0.57 and 0.40, respectively), whereas total and outer retinal MinI yielded negative correlations (R2 = 0.10 and 0.22). The multivariate model improved correlations (R2 = 0.66) yielding a root mean squared error of 3.8 decibel (dB). Feature importance analysis identified EZ loss as the most relevant predictor of function.

Conclusions

Multiple OCT-derived quantitative metrics used in combination can provide information to predict local sensitivities. The results indicate a strong relationship between retinal function and OCT measures, which contribute to the understanding of the retinal toxicity caused by HCQ as well as being applicable to outcome development for other degenerative diseases of the outer retina.

Clinical Update on Metamorphopsia: Epidemiology, Diagnosis and Imaging

Purpose: To discuss the pathophysiology of metamorphopsia, its characterisation using retinal imaging and methods of assessment of patient symptoms and visual function.Methods: A literature search of electronic databases was performedResults: Metamorphopsia has commonly been associated with vitreomacular interface disorders (such as epiretinal membrane) and has also regularly been noted in diseases of the retina and choroid, particularly age-related macular degeneration and central serous chorioretinopathy. Developments in optical coherence tomography retinal imaging have enabled improved imaging of the foveal microstructure and have led to the localisation of the pathophysiology of metamorphopsia within the retinal layers of the macula. Alteration of alignment of inner and outer retinal layers at various retinal loci has been identified using multimodal imaging in patients with metamorphopsia in a range of conditions. Although the Amsler Grid assessment of metamorphopsia is a useful clinical indicator, new emerging methods of metamorphopsia assessment with psychophysical tests such as M-CHARTS and preferential hyperacuity perimetry, have been developed.Conclusions: It appears that there is a complex relationship between visual acuity and metamorphopsia symptoms that vary between retinal conditions. Although metamorphopsia has traditionally been challenging to measure in the clinic, advances in technology promise more robust, easy-to-use tests. It is possible that home assessment of metamorphopsia, particularly in conditions such as age-related macular degeneration, may help to guide the need for further clinic evaluation and consideration of treatment.

A novel Bayesian adaptive method for mapping the visual field

Measuring visual functions such as light and contrast sensitivity, visual acuity, reading speed, and crowding across retinal locations provides visual-field maps (VFMs) that are extremely valuable for detecting and managing eye diseases. Although mapping light sensitivity is a standard glaucoma test, the measurement is often noisy (Keltner et al., 2000). Mapping other visual functions is even more challenging. To improve the precision of light-sensitivity mapping and enable other VFM assessments, we developed a novel hybrid Bayesian adaptive testing framework, the qVFM method. The method combines a global module for preliminary assessment of the VFM's shape and a local module for assessing individual visual-field locations. This study validates the qVFM method in measuring light sensitivity across the visual field. In both simulation and psychophysics studies, we sampled 100 visual-field locations (60° × 60°) and compared the performance of qVFM with the qYN procedure (Lesmes et al., 2015) that measured light sensitivity at each location independently. In the simulations, a simulated observer was tested monocularly for 1,000 runs with 1,200 trials/run, to compare the accuracy and precision of the two methods. In the experiments, data were collected from 12 eyes (six left, six right) of six human subjects. Subjects were cued to report the presence or absence of a target stimulus, with the luminance and location of the target adaptively selected in each trial. Both simulations and a psychological experiment showed that the qVFM method can provide accurate, precise, and efficient mapping of light sensitivity. This method can be extended to map other visual functions, with potential clinical signals for monitoring vision loss, evaluating therapeutic interventions, and developing effective rehabilitation for low vision.

Recent Advances of Computerized Graphical Methods for the Detection and Progress Assessment of Visual Distortion Caused by Macular Disorders

Recent advances of computerized graphical methods have received significant attention for detection and home monitoring of various visual distortions caused by macular disorders such as macular edema, central serous chorioretinopathy, and age-related macular degeneration. After a brief review of macular disorders and their conventional diagnostic methods, this paper reviews such graphical interface methods including computerized Amsler Grid, Preferential Hyperacuity Perimeter, and Three-dimensional Computer-automated Threshold Amsler Grid. Thereafter, the challenges of these computerized methods for accurate and rapid detection of macular disorders are discussed. The early detection and progress assessment of macular disorders can significantly enhance the required clinical procedure for the diagnosis and treatment of macular disorders.

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 the Amsler Grid Test in Evaluating Glaucomatous Central Visual Field Defects

PURPOSE

To investigate the efficacy of the Amsler grid test in detecting central visual field (VF) defects in glaucoma.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

Patients with glaucoma with reliable Humphrey 10-2 Swedish Interactive Threshold Algorithm standard VF on the date of enrollment or within the previous 3 months.

METHODS

Amsler grid tests were performed for each eye and were considered "abnormal" if there was any perceived scotoma with missing or blurry grid lines within the central 10 degrees ("Amsler grid scotoma"). An abnormal 10-2 VF was defined as ≥3 adjacent points at P < 0.01 with at least 1 point at P < 0.005 in the same hemifield on the pattern deviation plot. Sensitivity, specificity, and positive and negative predictive values of the Amsler grid scotoma area were calculated with the 10-2 VF as the clinical reference standard. Among eyes with an abnormal 10-2 VF, regression analyses were performed between the Amsler grid scotoma area and the 10-2 VF parameters (mean deviation [MD], scotoma extent [number of test points with P < 0.01 in total deviation map] and scotoma mean depth [mean sensitivity of test points with P < 0.01 in total deviation map]).

MAIN OUTCOME MEASURES

Sensitivity, specificity, and positive and negative predictive values of the Amsler grid scotoma area.

RESULTS

A total of 106 eyes (53 patients) were included (mean ± standard deviation age, 24-2 MD and 10-2 MD = 66±12 years, -9.61±8.64 decibels [dB] and -9.75±9.00 dB, respectively). Sensitivity, specificity, and positive and negative predictive values of the Amsler grid test were 68%, 92%, 97%, and 46%, respectively. Sensitivity was 40% in eyes with 10-2 MD better than -6 dB, 58% in eyes with 10-2 MD between -12 and -6 dB, and 92% in eyes with 10-2 MD worse than -12 dB. The area under the receiver operating characteristic curve of the Amsler grid scotoma area was 0.810 (95% confidence interval, 0.723-0.880, P < 0.001). The Amsler grid scotoma area had the strongest relationship with 10-2 MD (quadratic R(2)=0.681), followed by 10-2 scotoma extent (quadratic R(2)=0.611) and 10-2 scotoma mean depth (quadratic R(2)=0.299) (all P < 0.001).

CONCLUSIONS

The Amsler grid can be used to screen for moderate to severe central vision loss from glaucoma.

[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.

Strategies for following dry age-related macular degeneration

Spectral domain optical coherence tomography (SDOCT) provides a novel strategy for imaging and monitoring progression in patients with age-related macular degeneration (AMD). The advantage of SDOCT over other imaging modalities or functional tests is that one modality can be used to image both drusen and geographic atrophy while obtaining reproducible, quantitative data on both drusen morphology and the area of geographic atrophy. Moreover, this strategy enables the clinician to follow the disease as it progresses from drusen to both geographic atrophy and choroidal neovascularization. No other imaging modality is able to quantitatively assess all forms of AMD. This unique feature of SDOCT makes it the ideal imaging modality for monitoring patients with AMD, providing routine care, and for following patients in clinical trials designed to assess the efficacy of new drugs for the treatment of dry AMD.

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.

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.

[Monitoring of AMD patients on anti-vascular endothelial growth factor (VEGF) treatment. Practical notes on functional and anatomical examination parameters from drug approval studies, specialist information and case series]

Age-related macular degeneration (AMD) is one of the most common causes of blindness in western industrialised nations. Most AMD patients suffer from the dry early form of AMD; however, wet AMD with choroidal neovascularization (CNV) is the main cause of blindness in all AMD patients. New prospects have been developed in AMD treatment using pharmacological methods available for treating all subtypes of exudative AMD. A number of inhibiting and inducing growth factors, such as vascular endothelial growth factor (VEGF), are particularly important in the pathophysiology of wet AMD. The secreted VEGF appears to play a crucial role in the pathogenesis of CNV and macular edemas as a result of its angiogenetic and permeability-enhancing effect. This recognition led to the treatment approach now used, i.e., competitive VEGF blocking through intravitreal adminsitration of anti-VEGF drugs. The anti-VEGF durgs lead to a rapid decrease in retinal thickness. Optical coherence tomography (OCT) is a valuable monitoring tool, but may only be used to assist in decision-making. Clinical follow-up of patients and further treatment recommendations must always be guided by the overall clinical picture. Visual acuity is regarded as the decisive criterion for repeat treatment.

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.

Lack of benefit of early awareness to age-related macular degeneration

AIMS

To assess the rate of early awareness to the presence of age-related macular degeneration (AMD) and whether it enables early detection of transition to neovascular AMD (NVAMD) as compared with patients whose first presentation to an ophthalmologist is already at the neovascular stage of disease.

METHODS

A retrospective analysis of 268 eyes of 268 consecutive patients with newly diagnosed NVAMD that were treated in a tertiary referral centre was performed. Patients were classified into those who were unaware (Group 1), or aware (Group 2), of the fact that they had AMD before diagnosis of NVAMD. Visual acuity, lesion size and composition, and demographics were compared between both groups.

RESULTS

In all, 185 patients (69%) and 83 patients (31%) were classified to Groups 1 and 2, respectively. Patients in Groups 1 and 2 had similar demographic characteristics, presenting visual acuity and lesion size, and lesion compositions. Group 1 patients were more likely to have a positive history for smoking (41 vs26% in Group 2, P=0.03), whereas Group 2 patients were more likely to have positive family history for AMD (20 vs10%, P=0.02).

CONCLUSIONS

These data suggest that current screening methods fail to identify the majority of patients with AMD before the development of NVAMD. The findings also demonstrate that in the routine clinical setting, prior awareness of AMD may not facilitate early detection of treatable choroidal neovascularization lesions.

Diagnostik von Metamorphopsien bei Netzhauterkrankungen unterschiedlicher Genese

We investigated the ability of preferential hyperacuity perimeter (PHP) and Amsler grid testing to detect metamorphosia in patients with macular hole (MH), central serous retinopathy (CSR), epiretinal membranes (EM), intermediate AMD (iAMD), classic and occult choroidal neovascularization (CNV) due to AMD, and compared the results. A total of 147 patients (n =153 eyes) with classic (35 eyes) and occult (38 eyes) CNV, iAMD (13 eyes), MF (23 eyes), RCS (11 eyes), EM (13 eyes) and control group (20 eyes) were involved. All of these patients underwent corrected visual acuity and eye examinations inclusive of the Amsler grid. The PHP test was performed after pupil dilation. In all patients, fundus photography and optical coherence tomography (OCT) (Humphrey/Zeiss OCT III) were performed. In patients with CNV and CSR a fluorescein angiography was also performed. Metamorphopsia detection rates by Amsler grid and PHP were compared statistically. The sensitivity of PHP vs Amsler grid in detecting metamorphosia was 69% vs 85% in patients with MH, for CSR 64% vs 73%, EM 77% vs 100%, iAMD 85% vs 100%, classic CNV 83% vs 94% and occult CNV 81% vs 71%. The results for patients with occult CNV were significant (P =0.046), using the chi(2)-test. The PHP-test showed high sensitivity for diagnosing CNV. In occult CNV, PHP was superior to the Amsler grid in detecting metamorphopsia. In the other diseases involving the macular (MH, EM, CSR, iAMD), the detection rate and sensitivity of the Amsler grid was superior to PHP.

Visual function and dysfunction in early and late age-related maculopathy

Late age-related maculopathy (ARM) is responsible for the majority of blind registrations in the Western world among persons over 50 years of age. It has devastating effects on quality of life and independence and is becoming a major public health concern. Current treatment options are limited and most aim to slow progression rather than restore vision; therefore, early detection to identify those patients most suitable for these interventions is essential. In this work, we review the literature encompassing the investigation of visual function in ARM in order to highlight those visual function parameters which are affected very early in the disease process. We pay particular attention to measures of acuity, contrast sensitivity (CS), cone function, electrophysiology, visual adaptation, central visual field sensitivity and metamorphopsia. We also consider the impact of bilateral late ARM on visual function as well as the relationship between measures of vision function and self-reported visual functioning. Much interest has centred on the identification of functional changes which may predict progression to neovascular disease; therefore, we outline the longitudinal studies, which to date have reported dark-adaptation time, short-wavelength cone sensitivity, colour-match area effect, dark-adapted foveal sensitivity, foveal flicker sensitivity, slow recovery from glare and slower foveal electroretinogram implicit time as functional risk factors for the development of neovascular disease. Despite progress in this area, we emphasise the need for longitudinal studies designed in light of developments in disease classification and retinal imaging, which would ensure the correct classification of cases and controls, and provide increased understanding of the natural course and progression of the disease and further elucidate the structure-function relationships in this devastating disorder.

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

PURPOSE

We used the recently devised three-dimensional computer-based threshold Amsler grid test to acquire and identify typical patterns of visual field defects (scotomas) caused by age-related macular degeneration (AMD).

METHODS

Patients with AMD traced on a computer touch screen the borders of those areas on an Amsler grid that were missing from their field of vision. Scotomas were repeatedly outlined and recorded at different grid contrast levels. The resulting three-dimensional "hole" in the central 25 degrees of the visual field was further characterized by its slope, location, shape, and depth. The results were compared with fundus photographs and fluorescein angiograms.

RESULTS

Twenty-five patients and 41 eyes were examined. The three-dimensional depictions consistently demonstrated central scotomas with "scallop"-shaped borders and steplike patterns, with either steep slopes or a combination of steep and shallow slopes. The steep slopes corresponded to nonexudative AMD, while the shallow slopes indicated exudative AMD.

CONCLUSION

The three-dimensional computer-automated threshold Amsler grid test may demonstrate characteristic scotoma patterns in patients with AMD that conform to the respective fluorescein angiograms. The test shows promise as an effective tool in accurately evaluating, characterizing, and monitoring scotomas in patients with AMD. It may have the potential as a screening tool for the early diagnosis of AMD.