High-risk characteristics of fellow eyes of patients with unilateral neovascular age-related macular degeneration

Defining the structure-function relationship of specific lesions in early and advanced age-related macular degeneration

The objective of this study is to define structure-function relationships of pathological lesions related to age-related macular degeneration (AMD) using microperimetry and multimodal retinal imaging. We conducted a cross-sectional study of 87 patients with AMD (30 eyes with early and intermediate AMD and 110 eyes with advanced AMD), compared to 33 normal controls (66 eyes) recruited from a single tertiary center. All participants had enface and cross-sectional optical coherence tomography (Heidelberg HRA-2), OCT angiography, color and infra-red (IR) fundus and microperimetry (MP) (Nidek MP-3) performed. Multimodal images were graded for specific AMD pathological lesions. A custom marking tool was used to demarcate lesion boundaries on corresponding enface IR images, and subsequently superimposed onto MP color fundus photographs with retinal sensitivity points (RSP). The resulting overlay was used to correlate pathological structural changes to zonal functional changes. Mean age of patients with early/intermediate AMD, advanced AMD and controls were 73(SD = 8.2), 70.8(SD = 8), and 65.4(SD = 7.7) years respectively. Mean retinal sensitivity (MRS) of both early/intermediate (23.1 dB; SD = 5.5) and advanced AMD (18.1 dB; SD = 7.8) eyes were significantly worse than controls (27.8 dB, SD = 4.3) (p < 0.01). Advanced AMD eyes had significantly more unstable fixation (70%; SD = 63.6), larger mean fixation area (3.9 mm2; SD = 3.0), and focal fixation point further away from the fovea (0.7 mm; SD = 0.8), than controls (29%; SD = 43.9; 2.6 mm2; SD = 1.9; 0.4 mm; SD = 0.3) (p ≤ 0.01). Notably, 22 fellow eyes of AMD eyes (25.7 dB; SD = 3.0), with no AMD lesions, still had lower MRS than controls (p = 0.04). For specific AMD-related lesions, end-stage changes such as fibrosis (5.5 dB, SD = 5.4 dB) and atrophy (6.2 dB, SD = 7.0 dB) had the lowest MRS; while drusen and pigment epithelial detachment (17.7 dB, SD = 8.0 dB) had the highest MRS. Peri-lesional areas (20.2 dB, SD = 7.6 dB) and surrounding structurally normal areas (22.2 dB, SD = 6.9 dB) of the retina with no AMD lesions still had lower MRS compared to controls (27.8 dB, SD = 4.3 dB) (p < 0.01). Our detailed topographic structure-function correlation identified specific AMD pathological changes associated with a poorer visual function. This can provide an added value to the assessment of visual function to optimize treatment outcomes to existing and potentially future novel therapies.

Assessment of age‐related maculopathy using subjective vision tests

This paper reviews non-standard, clinical vision tests that may be used to detect the earliest visual loss in age-related maculopathy (ARM), before fundus changes are detected. We recommend a clinical test battery for all patients aged 60 years and older, comprising low luminance/low contrast (SKILL) VA or low contrast VA, desaturated D-15 colour vision assessment, flicker perimetry, glare recovery and dark adaptation if possible, together with conventional assessments of case history, ophthalmoscopy and high contrast visual acuity (VA) for the detection and diagnosis of ARM. Reading rate is also discussed as a potential indicator of early visual loss. For monitoring the progressive visual loss in age-related macular degeneration (AMD) and determining the requirements for optometric vision rehabilitation, we recommend more conventional clinical vision tests of distance and near visual acuity, reading rate, the effects of varying illumination and a functional central visual field assessment.

Simple Vision Function Tests that Distinguish Eyes with Early to Intermediate Age-related Macular Degeneration

PURPOSE

To present and compare baseline vision findings in eyes with early age-related macular degeneration (E-AMD), intermediate AMD (I-AMD), and age-similar participants with normal aging changes to the retina (No-AMD).

METHODS

Two hundred and thirty-seven eyes of 125 individuals (66.4% female, mean age 75.3 years) were tested monocularly using several simple, rapid psychophysical tests: high contrast visual acuity, low contrast visual acuity at reduced luminance, contrast sensitivity, shape discrimination hyperacuity, colour vision, reading rate, and glare recovery. Retinal status was determined using colour fundus photographs that were graded according to the Beckman Initiative for Macular Research Classification Committee scale. Logistic regression analyses with generalized estimating equations were used to assess the association between each vision variable and AMD category, while taking into account the correlation between the two eyes.

RESULTS

Three vision measures (contrast sensitivity [CS], shape discrimination hyperacuity [SDH], and colour discrimination [DesatCCS]) were significantly and independently associated with intermediate AMD. Relative Risk Ratios (RRR), 95% Confidence Intervals (in parentheses), beta coefficients, and significance (p) for the I-AMD vs. No-AMD model are: CS: RRR = 6.5 (1.91-22.0), beta = 1.87, p < .01; SDH: RRR = 2.34 (1.24-4.44), beta = 0.85, p < .001; DesatCCS: RRR = 1.43 (1.22-1.68), beta = 0.36, p < .001. Performance on these measures was significantly poorer for participants with I-AMD vs. No-AMD.

CONCLUSIONS

Simple screening tests distinguish eyes with intermediate AMD from eyes with less severe AMD or normal aging changes. This suggests that these vision measures may be significant predictors of which participants will go on to develop advanced AMD.

Visual Function in Eyes with Intermediate AMD with and without Retinal Pigment Abnormalities

SIGNIFICANCE

In intermediate AMD, a simple, clinically feasible vision test of sensitivity to radial deformation is significantly more impaired in eyes with hyperpigmentation than in eyes with large drusen but normal retinal pigmentation, consistent with the former's increased risk of progression to advanced AMD. This ongoing longitudinal study will determine whether this vision measure is predictive of progression to advanced AMD.

PURPOSE

This study aimed to determine whether simple, clinically feasible psychophysical measures distinguish between two levels of intermediate AMD that differ in their risk of progression to advanced AMD: eyes with large macular drusen and retinal pigment abnormalities versus eyes with large macular drusen without pigment abnormalities. Abnormal pigmentation in the presence of large drusen is associated with a higher risk of development of advanced AMD.

METHODS

Each eye of 39 individuals with the same form of intermediate AMD in both eyes was tested monocularly on a battery of vision tests. The measures (photopic optotype contrast sensitivity, discrimination of desaturated colors, and sensitivity to radial deformation [shape discrimination hyperacuity]) were compared for both dominant and nondominant eyes. ANOVA with eye (dominant or nondominant) as a within-subject factor and retinal status (pigmentary abnormalities present or absent from the macula) as a between-subject factor was used to determine statistical significance.

RESULTS

Sensitivity to radial deformation was significantly reduced in eyes with large drusen and pigment changes compared with eyes with large drusen and normal retinal pigmentation (-0.40 ± 0.04 vs. -0.61 ± 0.02, respectively; F = 13.31, P = .001).

CONCLUSIONS

In the presence of large macular drusen, performance on a shape discrimination task is related to the presence versus absence of abnormal retinal pigmentation, being poorer in the higher-risk group, supportive of the measure's potential to predict progression to advanced AMD.

Contrast sensitivity and binocular reading speed best correlating with near distance vision-related quality of life in bilateral nAMD

Purpose

Bilateral neovascular age‐related macular degeneration (nAMD) causes difficulties in daily life, especially with regard to near‐vision tasks, despite well preserved Early Treatment of Diabetic Retinopathy Study (ETDRS) best corrected visual acuity (BCVA) at distance. Therefore, alternative visual function measures were evaluated in terms of their correlation with vision‐related quality of life scores (QoL).

Methods

A prospective cross‐sectional pilot study including patients with a diagnosis of bilateral nAMD having lesions within the central 1 mm ETDRS grid subfield. Standardised testing included a vision‐related QoL assessment (NEI‐VFQ25), best corrected visual acuity (BCVA), low luminance visual acuity (LLVA), Radner maximum reading speed and Pelli‐Robson contrast sensitivity (CS).

Results

N = 54. The mean better eye (range) BCVA was 79 (55–96) letters, median (range) LLVA 79.5 (58–97) letters and median (range) CS 1.35 (0–1.65) log units. Mean binocular maximum reading speed was 117.33 ± 28.42 wpm. The best correlations with the near subscale score were found for CS followed by binocular maximum reading speed (r = 0.59, p = 0.0001; r = 0.36, p = 0.008, respectively). A weaker correlation was observed for the BCVA in the better eye (r = 0.33, p = 0.02). The correlation between the NEI‐VFQ25 distance subscale and BCVA was weaker (r = 0.37, p = 0.005) than the correlations with CS (r = 0.67, p = 0.0001) and LLVA (r = 0.40, p = 0.003).

Conclusions

For patients with a bilateral centre‐involving nAMD, the best correlation with near QoL was the better eye CS followed by maximum binocular reading speed. These measures could be valuable in quantifying vision‐related QoL outcomes in AMD clinical trials.

The Effect of Systemic Hyperoxia and Hypoxia on Scotopic Thresholds in People with Early and Intermediate Age-related Macular Degeneration

Purpose: Morphological retinal changes combined with functional evidence implicate hypoxia in the pathogenesis of age-related macular degeneration (AMD). However, the role of hypoxia in the scotopic threshold deficit reported in AMD has not been investigated. This study compared scotopic thresholds in participants with early and intermediate AMD recorded under conditions of systemic hypoxia, hyperoxia and normoxia. Materials and Methods: Over two sessions scotopic thresholds were measured with participants breathing 21% and 60% oxygen (n = 12 early AMD, n = 11 age-similar controls) or 21% and 14% oxygen (n = 16 early AMD, n = 20 age-similar controls). Thresholds were measured using a 'white', annular 12 degrees stimulus, using a QUEST procedure. Results: There was no statistically significant change in scotopic thresholds within the AMD or control group when breathing the hyperoxic gas mixture (60% oxygen) or the hypoxic gas mixture (14% oxygen) when compared to the normoxic condition (21% oxygen). There was also no statistically significant difference in scotopic thresholds between groups under the hyperoxic or hypoxic gas conditions. The difference between groups under the normoxic condition was not statistically significant for the hyperoxia study (p = .70), but did reach significance in the hypoxia study (p = .05). Conclusion: This study provided no evidence that breathing that breathing 14% or 60% oxygen altered scotopic thresholds in those with early AMD when compared to controls. However, the lack of elevated scotopic thresholds in the AMD group of the hyperoxia study is of note, as it is unlikely that hyperoxia would reduce thresholds which were not significantly raised at baseline, regardless of whether hypoxia was a factor in the disease pathogenesis. The findings of this study do not rule out a role for hypoxia in early AMD, but this needs to be assessed in future experiments using measures that differ significantly between people with AMD and controls.

Association of Longitudinal Changes in Drusen Characteristics and Retinal Layer Volumes with Subsequent Subtype of Choroidal Neovascularisation

AIM

To investigate the longitudinal correlation between drusen characteristics and retinal layer volumes pre conversion and subsequent type of choroidal neovascularisation (CNV).

METHODS

This was a single-centre retrospective study. The study participants were patients with wet age-related macular degeneration (AMD) in one eye who developed wet AMD in the contralateral eye, with at least 2 years of follow-up prior to conversion. The Moorfields Eye Hospital database was searched for eligible patients and their data were recorded. Eyes were classified as occult or classic based on fundus fluorescein angiography. Optical coherence tomography (OCT) images were analysed for drusen characteristics and retinal layer volumes were analysed over time using automated software (Topcon 3D OCT-2000 and Orion, Voxeleron LLC, respectively). All values were obtained at baseline as well as year 1 and year 2 before conversion to wet AMD.

RESULTS

Fifty-one eyes with bilateral CNV showed high correlation of type of CNV between eyes (kappa statistic 0.89). A total of 49 wet AMD eyes (29 occult, 20 classic) were analysed for drusen parameters. Two patients with retinal angiomatous proliferation were excluded. Drusen count, area, and volume did not differ by CNV type, but the rates of change of drusen area (p = 0.046) and drusen volume (0.022) were higher in the occult group in the year preceding CNV development. Of the 49 eyes, 17 (10 occult, 7 classic) with available good quality OCT were analysed for retinal layer volumes. There was a progressive reduction in outer nuclear layer (ONL) volume (p = 0.002) and an expansion in outer plexiform layer volume (p = 0.015) in eyes that developed occult CNV.

CONCLUSION

Our study shows that rate of increase in drusen load and reduction in ONL are significant features seen in eyes developing occult CNV, highlighting new imaging markers that need to be replicated in larger studies. These markers provide insight into the pathogenesis of CNV and may serve as prognostic indicators, as classic CNV carries a poorer prognosis compared to occult CNV.

Driving and Age-Related Macular Degeneration

This article reviews the research literature on driving and age-related macular degeneration, which is motivated by the link between driving and the quality of life of older adults and their increased collision rate. It addresses the risk of crashes, driving performance, driving difficulty, self-regulation, and interventions to enhance, safety, and considers directions for future research.

Cone photoreceptor macular function and recovery after photostress in early non-exudative age-related macular degeneration

Purpose

To identify parameters from cone function and recovery after photostress that detect functional deficits in early non-exudative age-related macular degeneration (AMD) and to determine the repeatability of these parameters.

Methods

Cone-mediated visual function recovery after photostress was examined in three groups of subjects: young normal subjects (ages 20–29; N=8), older normal subjects (ages 50–90; N=9), and early non-exudative AMD subjects (ages 50–90; N=12). Eight AMD and four normal subjects were retested 1 year after the initial evaluation. Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) and parameters of cone function (baseline cone sensitivity and cone recovery half-life following photobleach) were measured and compared between AMD and normal subjects. Short-term repeatability was assessed for each subject’s initial evaluation. Long-term repeatability was assessed by comparing outcomes from the initial evaluation and 1-year follow-up.

Results

The mean baseline cone threshold was significantly worse in subjects with early AMD compared to older normal subjects (−1.80±0.04 vs −1.57±0.06 log cd/m²p=0.0027). Moreover, the baseline cone threshold parameter exhibited good short-term (intraclass correlation coefficient [ICC]=0.88) and long-term (ICC=0.85) repeatability in all subjects. The cone intercept parameter and ETDRS VA were not significantly different between AMD and older normal subject groups. Cone recovery half-life was significantly different between older normal and AMD subject groups (p=0.041). Neither ETDRS VA nor cone function parameters were significantly different for any group at the 1-year follow-up.

Conclusion

The baseline cone threshold shows potential as a novel parameter to assess visual dysfunction in early AMD. This outcome consistently detected deficits in AMD subjects, and differentiated them from age-matched controls with high test–retest repeatability.

Six-Year Incidence and Risk Factors of Age-Related Macular Degeneration in Singaporean Indians: The Singapore Indian Eye Study

We aimed to determine the 6-year incidence and risk factors of age-related macular degeneration (AMD) in first and second generations of Singaporean Indians. Baseline examination was conducted in 2007-9 and 6-year propsective follow-up examination of this Indian population in 2013-5. All participants underwent interviews with questionnaires and comprehensive medical and eye examinations. Incidence was age-standardized to Singaporean 2010 census. Risk factors associated with AMD incidence were assessed and compared between first and second generations of immigrants. Among 2200 persons who participated in the follow-up examination (75.5% response rate), gradable fundus photographs were available in 2105. The 6-year age-standardized incidences of early and late AMD were 5.26% and 0.51% respectively. Incident early AMD was associated with cardiovascular disease history (HR 1.59, 95% CI 1.04-2.45), underweight body mass index (BMI) (HR 3.12, 95% CI 1.37-7.14) (BMI of <18.5 vs 18.51-25 kg/m2), heavy alcohol drinking (HR 3.14 95% CI 1.25-7.89) and ARMS2 rs3750847 homozygous genetic loci carrier (HR 2.52, 95% CI 1.59-3.99). We found a relatively low incidence of early AMD in this Singaporean Indian population compared to Caucasian populations. Both first and second-generation Indian immigrants have similar incidence and risk factor patterns for early AMD.

Measurement of Retinal Sensitivity on Tablet Devices in Age-Related Macular Degeneration

PURPOSE

We compared measurements of central retinal sensitivity on a portable, low-cost tablet device to the established method of microperimetry in age-related macular degeneration (AMD).

METHODS

A customized test designed to measure central retinal sensitivity (within the central 1° radius) on a tablet device was developed using an open-source platform called PsyPad. A total of 30 participants with AMD were included in this study, and all participants performed a practice test on PsyPad, followed by four tests of one eye and one test of the other eye. Participants then underwent standardized microperimetry examinations in both eyes.

RESULTS

The average test duration on PsyPad was 53.9 ± 7.5 seconds, and no significant learning effect was observed over the examinations performed (P = 1.000). The coefficient of repeatability of central retinal sensitivity between the first two examinations on PsyPad was ±1.76 dB. The mean central retinal sensitivity was not significantly different between PsyPad (25.7 ± 0.4 dB) and microperimetry (26.1 ± 0.4 dB, P = 0.094), and the 95% limits of agreement between the two measures were between -4.12 and 4.92 dB.

CONCLUSIONS

The measurements of central retinal sensitivity can be performed effectively using a tablet device, displaying reasonably good agreement with those obtained using the established method of microperimetry.

TRANSLATIONAL RELEVANCE

These findings highlight the potential of tablet devices as low-cost and portable tools for developing and performing visual function measures that can be easily and widely implemented.

Detection of early age-related macular degeneration using novel functional parameters of the focal cone electroretinogram

The focal cone electroretinogram is a sensitive marker for macular disease, but have we unlocked its full potential? Typically assessment of waveform parameters is subjective and focuses on a small number of locations (e.g. the a-wave). This study evaluated the discriminatory and diagnostic potential of 4 conventional and 15 novel, objectively determined, parameters in patients with early Age-related Macular Degeneration. Focal cone electroretinograms were recorded in 54 participants with early Age-related Macular Degeneration (72.9±8.2 years) and 54 healthy controls (69±7.7 years). Conventional a and b wave amplitudes and implicit times were measured and compared to novel parameters derived from both the 1st and 2nd derivatives and the frequency-domain power spectrum of the electroretinogram.Statistically significant differences between groups were shown for all conventional parameters, the majority of 1st and 2nd derivative parameters and the power spectrum at 25 and 30 Hz. Receiver operating characteristics showed that both conventional and 1st and 2nd derivative implicit times had provided the best diagnostic potential. A regression model showed a small improvement over any individual parameter investigated. The non-conventional parameters enhanced the objective evaluation of the focal electroretinogram, especially when the amplitude was low. Furthermore, the novel parameters described here allow the implicit time of the electroretinogram to be probed at points other than the peaks of the a and b waves. Consequently these novel analysis techniques could prove valuable in future electrophysiological investigation, detection and monitoring of Age-related Macular Degeneration.

Ocular Risk Factors for Exudative AMD: A Novel Semiautomated Grading System

Purpose. To evaluate the contribution of the ocular risk factors in the conversion of the fellow eye of patients with unilateral exudative AMD, using a novel semiautomated grading system. Materials and Methods. Single-center, retrospective study including 89 consecutive patients with unilateral exudative AMD and ≥3 years of followup. Baseline color fundus photographs were graded using an innovative grading software, RetmarkerAMD (Critical Health SA). Results. The follow-up period was 60.9 ± 31.3 months. The occurrence of CNV was confirmed in 42 eyes (47.2%). The cumulative incidence of CNV was 23.6% at 2 years, 33.7% at 3 years, 39.3% at 5 years, and 47.2% at 10 years, with a mean annual incidence of 12.0% (95% CI = 0.088–0.162). The absolute number of drusen in the central 1000 and 3000 μm (P < 0.05) and the absolute number of drusen ≥125 µm in the central 3000 and 6000 µm (P < 0.05) proved to be significant risk factors for CNV. Conclusion. The use of quantitative variables in the determination of the OR of developing CNV allowed the establishment of significant risk factors for neovascularization. The long follow-up period and the innovative methodology reinforce the value of our results. This trial is registered with ClinicalTrials.gov NCT00801541.

Association of ARMS2 genotype with bilateral involvement of exudative age-related macular degeneration

PURPOSE

To study the association of ARMS2 A69S genotype with the development of exudative age-related macular degeneration (AMD) in the unaffected fellow eye and to estimate the duration until the development of AMD in the second eye.

DESIGN

Retrospective cohort study.

METHODS

We retrospectively reviewed 326 patients who had exudative AMD in at least 1 eye, genotyping of ARMS2 A69S, and a minimum follow-up of 2 years. Survival analysis and Cox proportional hazard regression analysis were used to examine the association between candidate factors and the duration until the development of AMD in the second eye.

RESULTS

One hundred nineteen patients (36.5%) had bilateral exudative AMD at the initial visit. A risk allele of ARMS2 A69S was more frequently seen in patients with bilateral AMD (P = .0270) than in those with unilateral AMD. Of the 207 unilateral AMD patients, 23 (11.1%) had AMD in the fellow eye after a mean duration of 56.3 ± 40.4 months. Fellow-eye involvement was associated with ARMS2 A69S genotype (hazard ratio [HR], 2.673; P = .0013), age (HR, 1.102; P = .0005), and smoking history (HR, 0.680; P = .3663). As HRs indicate, correlation of genotype (2.673) was as high as that of 10-year aging (1.102(10) = 2.641). Survival analysis revealed that patients with risk homozygous (TT) genotype had second-eye involvement significantly earlier than those with other genotypes (P = .0028). When the observation duration reached 120 months, second-eye involvement had developed in 50%, 6.6%, and 11.2% of the TT, GT, and GG cohorts, respectively.

CONCLUSION

ARMS2 A69S genotype is associated with second-eye involvement of exudative AMD and with the period between first- and second-eye involvements.

Development of typical age-related macular degeneration and polypoidal choroidal vasculopathy in fellow eyes of Japanese patients with exudative age-related macular degeneration

PURPOSE

To investigate the development of typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) in fellow eyes of Japanese patients with exudative AMD.

DESIGN

Retrospective observational consecutive case series.

METHODS

Two hundred and sixteen Japanese patients were enrolled in this study from the outpatient clinic of the University of Tokyo Hospital. Ninety-one patients had typical AMD and one hundred and twenty-five patients had PCV. The average follow-up period was 33.6 and 25.1 months for typical AMD and PCV patients.

RESULTS

The cumulative incidence of involvement in fellow eyes with overall exudative AMD, including both typical AMD and PCV, was 3.4% in one year, 9.3% in three years, and 11.3% in five years. It was 3.6%, 7.3%, and 11.2% in typical AMD, and 3.2%, 11.1%, and 11.1% in PCV in one, three, and five years, respectively. Before the development of exudative AMD, patients with typical AMD had a variety of funduscopic findings including retinal pigment epithelium (RPE) atrophy, drusen, drusenoid pigment epithelial detachments (PED), and normal macula. PCV patients, on the other hand, had funduscopic findings of RPE atrophy. Inner choroidal vascular abnormality of vascular network and polypoidal formation was observed in several eyes before the clinical manifestation of exudative changes.

CONCLUSIONS

Typical AMD and PCV had similar probabilities of involving the fellow eye in unilaterally affected Japanese patients. RPE atrophy was a prevailing finding in fellow eyes of patients who developed PCV. In PCV, choroidal vascular network and polypoidal formation gradually grow before exudative changes.

Effect of Aerodiol administration on ocular arteries in postmenopausal women

OBJECTIVE

The aim of the present study was to evaluate the alteration of ocular blood hemodynamics after intranasal administration of 17beta-estradiol, through measurement of the ophthalmic artery (OA) and the central retinal artery (CRA) using color duplex sonography.

METHODS

Thirty healthy women who had been naturally postmenopausal for at least 1 year were enrolled in the study. A randomized, placebo-controlled, crossover, double-blinded study was conducted of the acute effect of 17beta-estradiol (Aerodiol; Servier, Chambrayles-Tours, France) on OA and CRA blood flow using color duplex sonography.

RESULTS

The peak systolic and end diastolic velocities of the CRA were increased significantly after 17beta-estradiol administration compared with placebo. A significant decrease was also found in the pulsatility and resistive indices of the CRA. However, there were no statistically significant differences in OA flow velocities or pulsatility and resistive indices.

CONCLUSIONS

Nasal 17beta-estradiol administration in postmenopausal women causes an improvement in the ocular vascular Doppler indices. These results suggest that there could be a positive effect of Aerodiol on middle-sized arteries and arterioles.

The Natural History and Prognosis of Neovascular Age-Related Macular Degeneration

PURPOSE

To describe the natural history and progression of visual loss in eyes with untreated neovascular age-related macular degeneration (AMD).

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Four thousand three hundred sixty-two untreated neovascular AMD patients from published interventional studies.

METHODS

A systematic review of the literature from 1980 to August 2005 was performed. Studies reporting disease progression outcomes for untreated patients with neovascular AMD were included. Outcome measures were summarized using simple counts and means. Random effects meta-analyses were conducted and tests of heterogeneity were performed where appropriate.

MAIN OUTCOME MEASURES

Changes in visual acuity (VA) loss, development of comorbidities, and fellow eye involvement.

RESULTS

Fifty-three primary studies were included. Nearly half of the studies (28) were randomized clinical trials. The quality of the studies was high, with over 80% providing level I or II evidence. Mean baseline VA among study patients was 0.64 logarithm of the minimum angle of resolution (logMAR) (approximately 20/87 Snellen). The mean VA change in logMAR progressed from 0.1 (1 line lost) at 3 months to 0.3 (2.7 lines lost) after 12 months and 0.4 (4 lines lost) after 24 months. The proportion of patients who developed severe vision loss (>6 lines) from baseline increased from 21.3% at 6 months to 41.9% by 3 years. The proportion of patients with VA worse than logMAR 1.0 (20/200 Snellen) increased from 19.7% at baseline to 75.7% by 3 years. Neovascular AMD developed in the fellow eye in 12.2% of patients by 12 months and in 26.8% by 4 years. Meta-analyses of vision outcome by subtype of neovascular AMD were not possible.

CONCLUSIONS

A doubling of the visual angle of presenting VA may be expected to occur in the year after initial presentation in eyes with untreated neovascular AMD. No conclusions can be drawn as to the differences in rates of disease progression by neovascular AMD subtype. The diversity of reporting formats, paucity of long-term natural history data, and heterogeneity among the reported clinical studies impose limits to the clear understanding of long-term prognosis for visual function in neovascular AMD.

Two genetic pathways for age-related macular degeneration

The discovery of strong associations of the His402 variant of complement factor H (CFH) and the change in the promoter region of HtrA serine peptidase 1 (HTRA1) with age-related macular degeneration (AMD) have altered our conception of the pathophysiology of this disease. The complement system has been placed at the center of a flurry of research interest, and a similar growth in attention to the serine proteases is not far behind. The specific role of these variants in causing AMD is unknown, but they will undoubtedly lead to a deeper understanding of the biological mechanisms and will point to new avenues for pharmacologic management. Furthermore, these variants will enable clinicians and investigators to identify people at high risk for this condition, thereby establishing the preconditions for preventing the disease.

Ten-year incidence and progression of age-related maculopathy: the blue Mountains Eye Study

PURPOSE

To assess the 10-year incidence of age-related maculopathy (ARM) in an older Australian cohort.

DESIGN

Population-based cohort study.

PARTICIPANTS

Three thousand six hundred fifty-four Blue Mountains Eye Study participants > or =49 years old were examined during 1992 through 1994; 2335 (75% of survivors) were reexamined after 5 years (1997-1999) and 1952 (76% of survivors) after 10 years (2002-2004).

METHODS

The same graders performed retinal photographic grading in all examinations, using the Wisconsin Age-Related Maculopathy Grading System. Photographs of participants with ARM lesions at any of the examinations were subsequently regraded using a side-by-side comparison method.

MAIN OUTCOME MEASURES

The diagnosis of incident late ARM was given if neovascular ARM or geographic atrophy was detected at either follow-up examination in persons free of these lesions at baseline. Incident early ARM was diagnosed if early ARM (soft indistinct or reticular drusen or combined soft distinct drusen and retinal pigment abnormality) was present in persons free of early and late ARM at baseline. Age-related maculopathy incidence was calculated using Kaplan-Meier methods to incorporate information from both 5- and 10-year examinations. Discrete logistic models were used to assess the risk of incident late ARM according to various baseline factors, including early ARM lesion characteristics.

RESULTS

After excluding 72 late ARM cases present at baseline, 2395 of 3582 subjects at risk of late ARM (67%) were reexamined at either follow-up time point or both follow-up time points. Over the 10-year period, 72 of 2395 subjects (3.7%) developed late ARM and 266 of 2255 subjects (14.1%) developed early ARM. After age standardization to the Beaver Dam Eye Study population, our 10-year incidences of late and early ARM were 2.8% and 10.8%, respectively. Baseline age and early ARM lesion characteristics and severity were strong predictors of late ARM incidence.

CONCLUSIONS

Long-term follow-up of this older population confirms that the risk of ARM progression is related strongly to the severity of early-stage lesions. The study provides evidence-based criteria for identifying persons at high risk of developing late ARM.

HTRA1 promoter polymorphism in wet age-related macular degeneration

Age-related macular degeneration (AMD), the most common cause of irreversible vision loss in individuals aged older than 50 years, is classified as either wet (neovascular) or dry (nonneovascular). Inherited variation in the complement factor H gene is a major risk factor for drusen in dry AMD. Here we report that a single-nucleotide polymorphism in the promoter region of HTRA1, a serine protease gene on chromosome 10q26, is a major genetic risk factor for wet AMD. A whole-genome association mapping strategy was applied to a Chinese population, yielding a P value of <10(-11). Individuals with the risk-associated genotype were estimated to have a likelihood of developing wet AMD 10 times that of individuals with the wild-type genotype.

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.

Effect of age related macular degeneration on the Eger macular stressometer photostress recovery time

AIM

To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function.

METHODS

EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with both forms of the condition (mean age 79 (SD 13) years). Measurements were made on two occasions separated by 1 year. Intrasession repeatability was assessed by repeating the measures after a 10 minute recovery period at the first visit. Distance visual acuity was measured with a logMAR chart, near visual acuity with a MNRead chart at 25 cm, contrast sensitivity with a Pelli-Robson chart, and the presence of central visual disturbance assessed with an Amsler grid. A questionnaire was used to assess self reported difficulties with glare recovery.

RESULTS

The average EMS recovery time was 11.0 (SD 8.9) seconds, decreasing by 1.6 (5.2) seconds on repeated measurement (p<0.05). EMS photostress recovery was not correlated with visual function measures or subjective difficulties with lights (p>0.05). EMS photostress recovery time did not predict those whose vision decreased over the following year compared with those among whom it remained stable.

CONCLUSIONS

The EMS test is not a useful tool in determining the severity or progression of AMD.

Evaluation of retinal function using the Dynamic Focal Cone ERG

The development of effective means of assessing visual function in retinal disease holds the key to improved understanding of pathogenesis, and better monitoring of treatment outcomes. In diseases such as age-related macular degeneration, in which the primary locus of dysfunction is the outer retina, tests which provide a direct measure of the functional integrity of the photoreceptor/retinal pigment epithelium (RPE) complex are of great importance. Recovery of retinal function following adaptation to a bright light requires the healthy function of photoreceptors, RPE, Bruch's membrane and choroidal circulation, making an assessment of this recovery a potentially useful clinical tool. However, current techniques are either subjective in nature, or are influenced by post-retinal processing of visual information. This report describes a novel technique, the 'Dynamic Focal Cone Electro-retinogram (ERG)', which allows direct, objective assessment of the recovery of macular function following photopigment bleach. A series of 41 Hz ERGs was recorded, and ERG amplitude was plotted as a function of time following cessation of the bleach. Normative data was collected from 10 healthy subjects. For all subjects, there was no measurable ERG immediately after the bleach, but the amplitude had returned to a pre-bleach level within 4 min. The amplitude recovery data were adequately described both by an exponential recovery function and by a model based on a rate-limited recovery process. We conclude that this technique provides a clinically applicable, objective measure of outer retinal recovery.

Second eye of patients with unilateral neovascular age-related macular degeneration: Caucasians vs Chinese

PURPOSE

To investigate the correlation between morphological features of choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD) in the first eye and the severity of age-related maculopathy (ARM) in the fellow eyes in two racial groups: Caucasians and Chinese.

PARTICIPANTS

A total of 135, fluorescein angiograms of patients with unilateral neovascular AMD and ARM in the fellow eyes were included in the study: 38 Caucasians from King's College Hospital, UK; 45 Caucasians from West Kent Eye Centre, UK; 52 Chinese from Hong Kong Eye Hospital, Hong Kong.

MAIN OUTCOME MEASURES

CNV subtype in the affected eye and ARM severity in the second eyes.

RESULTS

Although the proportion of CNV subtypes in the three groups were similar, the Chinese cohort showed significantly less ARM severity compared to the Caucasian cohorts (P < 0.05).

CONCLUSION

Although drusen and retinal pigmentary changes may be prognostic indicators of CNV, this study suggest that other factors contribute significantly to the pathogenesis of CNV in AMD.

Drusen classification in bilateral drusen and fellow eye of exudative age-related macular degeneration

AIM

To assess the value of the modified international classification system in screening high-risk patients with bilateral age-related maculopathy (ARM) from those with lower risk characteristics.

METHODS

In total, 164 digital images of 106 patients with either bilateral ARM (group A) or the fellow eyes of unilateral exudative age-related macular degeneration (AMD) (Group B) were included. Patients with no signs of ARM in both eyes or those with bilateral late AMD were excluded. The images were randomised and then graded by two masked ophthalmologists based on the modified International Classification of ARM.

RESULTS

The interobserver consistency between the two graders was high with a Kappa value of 0.82 (SE 0.34, P<0.0001). There were no significant differences in the distribution of the stages of ARM between the two subgroups. Stage 3 was the most common stage in each group for both graders followed by stage 2a in the bilateral drusen group. Stages 1a, 2a and 2b were equally the next common stage in the fellow eye of chordial neovascularisation group.

CONCLUSION

A screening system based on clinical characteristics would be of value in risk prediction in a clinical setting. Type of Drusen alone, as identified by the modified International grading system, may not be reliably predictive in screening for patients who are at high risk of developing choroidal neovascularisation.

Improved contrast of subretinal structures using polarization analysis

PURPOSE

To improve the ability to detect and quantify the early retinal changes associated with aging, age-related maculopathy, and age-related macular degeneration.

METHODS

A computational approach was implemented for analyzing images using a readily available polarimeter that is used for glaucoma diagnosis. This device, the GDx Nerve Fiber Analyzer (Laser Diagnostic Technologies, Inc., San Diego, CA), takes a series of images as a function of the polarization angle of the illuminating light. For each of 20 input polarizations, pairs of retinal images are digitized. One image is made of the light returning from the eye that is polarized parallel to the input light, and the other image is made of the light that is rotated by 90 degrees from the input polarization. Using the raw data from these 40 images, and a simplified model of the polarization properties of the eye, we calculated the amount of light that returns in a parallel polarized state, and the amount of light that is depolarized by multiple scattering. Measurements were made in seven subjects with small drusen.

RESULTS

The depolarized light image produced a 3.4 times higher contrast of drusen and subretinal changes than the parallel polarized light images.

CONCLUSIONS

Polarization-sensitive imaging combined with a simple computational approach allows the measurement of the retinal distribution of multiply scattered light. With this technique, retinal imaging of age-related changes in retinal and subretinal tissue can be improved.

Color Doppler imaging of choroidal circulation in patients with asymmetric age-related macular degeneration

We aimed at evaluating the possible role of choroidal perfusion abnormalities in the development of choroidal neovascularisation (CNV) in patients with age-related macular degeneration (AMD). Twenty-six patients who had non-exudative AMD in the first eye and CNV secondary to AMD in the fellow eye were enrolled. Blood flow velocities, vessel pulsatilities and resistivities were measured from ophthalmic artery, nasal and temporal posterior ciliary arteries using colour Doppler imaging. Systolic and diastolic velocities were lower in eyes with CNV for all vessels, except for the systolic velocity of the nasal posterior ciliary artery (p >0.05). Pulsatility and resistivity indices were higher in eyes with CNV for all vessels. This difference was statistically significant for the resistivity index of the nasal and temporal posterior ciliary arteries (p = 0.032 and p = 0.021, respectively) and the pulsatility index of the nasal posterior ciliary artery (p = 0.035). We have shown that in patients with AMD choroidal blood flow is more impaired in the eyes with CNV than in the fellow eyes.

Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

We measured changes to cone photoreceptors in patients with early age-related macular degeneration. The data of 53 patients were compared with normative data for color matching measurements of long- and middle-wavelength-sensitive cones in the central macula. A four-parameter model quantified cone photopigment optical density and kinetics. Cone photopigment optical density was on average less for the patients than for normal subjects and was uncorrelated with visual acuity. More light was needed to reduce the photopigment density by 50% in the steady state for patients. These results imply that cone photopigment optical density is reduced by factors other than slowed kinetics.

The second eye of Japanese patients with unilateral exudative age related macular degeneration

AIM

To clarify the incidence of choroidal neovascularisation (CNV) and predisposing findings for development of CNV in the second eye of Japanese patients with unilateral exudative age related macular degeneration (AMD).

METHODS

The second eyes of unilaterally affected patients with exudative (neovascular) AMD treated in our clinic during the past 10 years (1988-97) were carefully followed up for more than a year. Evidence of CNV was confirmed by fluorescein and indocyanine green angiography. Macular lesions in patients, in whom CNV developed in the second eye, were retrospectively evaluated from patient records.

RESULTS

170 patients met the criteria. The average follow up period was 47 months (range 12-108 months). All patients were Japanese. CNV developed in the second eye in 12 (7%) of 170 patients, 30.3 months on average after the first examination. Cumulative incidence of developing CNV in the second eye using Kaplan-Meier life table analysis was: 0.6% by 1 year, 5.6% by 3 years, and 12.3% by 5 years, and was relatively low compared with that in white patients. CNV developed most frequently from serous pigment epithelial detachment (PED) in the macula (58%). Soft drusen were not prevalent and risk of developing CNV was not very high (18%).

CONCLUSION

It was confirmed that there were some differences in the incidence and predisposing findings for CNV developing in AMD among Japanese and other Asian patients compared with those in white people. It is important to recognise these differences between the two populations to understand the pathogenesis and epidemiology of AMD.

Estrogen-replacement therapy: effects on retrobulbar hemodynamics

PURPOSE

Estrogen-replacement therapy causes vasodilation and increased blood flow in major peripheral arteries. We examined the role that estrogen may play in enhancing perfusion within the watersheds of several major and minor retrobulbar arteries.

METHODS

Postmenopausal women receiving estrogen-replacement therapy (n = 16) were compared with both age-matched women not receiving estrogen (n = 16) and with young women (n = 20). Studies involved color Doppler imaging analysis of flow velocities measured in the ophthalmic, central retinal, and nasal and temporal posterior ciliary arteries.

RESULTS

In the ophthalmic artery, young women and postmenopausal women receiving estrogen exhibited reduced resistance indexes as compared with postmenopausal women not receiving estrogen (each P <. 001). In contrast, flow velocities in the central retinal artery were similar among the three groups of women. In the posterior ciliary arteries, a different pattern emerged: young women, as compared with either group of postmenopausal women, showed greater peak systolic and end-diastolic velocities at similar resistance index (each P <.05).

CONCLUSIONS

Estrogen-replacement therapy in postmenopausal women apparently helps reduce vascular resistance distal to the ophthalmic artery to levels matching those of young women. However, estrogen replacement has little impact on flow velocities in the posterior ciliary arteries. In those vessels, aging per se may reduce perfusion, potentially contributing to the age-dependent risk of major eye diseases, such as glaucoma and age-related macular degeneration.