Impact of Reticular Pseudodrusen on Microperimetry and ... · Color fundus photographs were obtained with a Canon nonmydriatic camera (Canon CR6-45NM; Canon, Saitama, Japan). Spectral-domain

Retina

Impact of Reticular Pseudodrusen on Microperimetry andMultifocal Electroretinography in IntermediateAge-Related Macular Degeneration

Zhichao Wu, Lauren N. Ayton, Galina Makeyeva, Robyn H. Guymer, and Chi D. Luu

Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Victoria, Australia

Correspondence: Zhichao Wu, Mac-ular Research Unit, Centre for EyeResearch Australia,Level 1, 32 Gisborne Street, EastMelbourne, VIC 3002, Australia;[email protected].

RHG and CDL contributed equally tothe work presented here and shouldtherefore be regarded as equivalentauthors.

RHG and CDL are joint senior authors.

Submitted: December 7, 2014Accepted: February 22, 2015

Citation: Wu Z, Ayton LN, MakeyevaG, Guymer RH, Luu CD. Impact ofreticular pseudodrusen on micro-perimetry and multifocal electroreti-nography in intermediate age-relatedmacular degeneration. Invest Oph-

thalmol Vis Sci. 2015;56:2100–2106.DOI:10.1167/iovs.14-16210

PURPOSE. To examine the influence of reticular pseudodrusen (RPD) on retinal and visualfunction in intermediate AMD using multifocal electroretinography (mfERG) and micro-perimetry.

METHODS. In a prospective cross-sectional study, microperimetry and mfERG testing, followedby color fundus photography, near-infrared reflectance imaging and spectral-domain opticalcoherence tomography (SD-OCT) scans were performed in 120 eyes from 60 participantswith bilateral intermediate AMD. The number of subfields with pigmentary changes and RPDwithin the central 3-mm diameter of the Early Treatment of Diabetic Retinopathy Study(ETDRS) grid and drusen cube root volume within the central 3-mm diameter wasdetermined. The influence of these pathological features on microperimetry and mfERG inthis region were examined.

RESULTS. Microperimetric sensitivity was not significantly associated with the presence andextent of RPD (P ¼ 0.068), but with drusen volume and extent of pigmentary changes (P <0.001 for both). However, the presence and extent of RPD was independently andsignificantly associated with mfERG implicit time, along with drusen volume and the extent ofpigmentary changes (P � 0.023). The mfERG response amplitude was not significantlyassociated with the presence and extent of RPD (P ¼ 0.130).

CONCLUSIONS. The presence and extent of RPD was associated with functional changes onmfERG implicit time, but not mfERG response amplitude or microperimetry. These findingssuggest that the presence of RPD in eyes with intermediate AMD has a significant influenceon cone-mediated neuroretinal function, without a significant influence on mesopic visualfunction as determined on microperimetry.

Keywords: AMD, spectral-domain optical coherence tomography, microperimetry, multifocalelectroretinography

The presence of drusen is the hallmark feature of AMD,where drusen characteristics such as size or extent, along

with the presence of pigmentary abnormalities have tradition-ally been used to determine the risk of progression to theadvanced stages of AMD.1–3 More recently, the feature ofreticular pseudodrusen (RPD) has also been increasinglyrecognized as another additional important risk factor for thedevelopment of advanced AMD.4–9

On spectral-domain optical coherence tomography (SD-OCT), RPD are visualized as hyperreflective signals locatedabove the retinal pigment epithelium (RPE) band, which canalso be accompanied by disruption of the inner segmentellipsoid (ISe) band.10–13 Some studies using adaptive-opticsscanning laser ophthalmoscopy (AO-SLO) have also observedchanges to the reflectivity and density of the cone photore-ceptors overlying RPD,14–17 leading some to suggest a potentialinfluence on retinal and visual function.14,15

Investigation into the influence of RPD on retinal and visualfunction has been performed using different measures. Onestudy examined this using multifocal electroretinography(mfERG),18 an objective electrophysiological measure of retinalfunction, and reported that there was no significant difference

in cone-mediated retinal function between areas with andwithout RPD in an eye. Other studies have investigated theinfluence of RPD using microperimetry, a psychophysicalmeasure of visual function, and reported a significant reductionin sensitivity to luminance increment under mesopic condi-tions for eyes with only RPD (without typical drusen)compared with healthy eyes19 and eyes with only drusen (noRPD).20

To date, these studies have examined eyes where only RPDwere exclusively present, yet RPD are often present along withfeatures of the early stages of AMD.6–10,21,22 Therefore, wesought to examine the influence that the presence of RPD hadon retinal and visual function in eyes with intermediate AMDusing mfERG and microperimetry in this study.

METHODS

This study was approved by the Human Research EthicsCommittee of the Royal Victorian Eye and Ear Hospital (RVEEH)and was conducted in adherence with the Declaration ofHelsinki. All participants provided written informed consentafter an explanation of all test procedures.

Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

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Participants

Participants with AMD were recruited from the medical retinaclinic at the Royal Victorian Eye and Ear Hospital (RVEEH;Victoria, Australia) and private ophthalmology clinics and wereseen at the Centre for Eye Research Australia as part of a studyof the structural and functional changes in the early stages ofAMD. All participants were required to be over 50 years of age,have best-corrected visual acuity of better than 20/40 (or 0.30logMAR) and intermediate AMD in both eyes. IntermediateAMD was defined as an eye having drusen greater than 125 lm,with or without pigmentary abnormalities.23 The exclusioncriteria for any participants included the presence of anyatrophic changes including geographic atrophy (GA), drusen-associated atrophy detected on SD-OCT or nascent geographicatrophy (nGA),24 choroidal neovascularization (CNV), signifi-cant cataracts, glaucoma, amblyopia, and any corneal pathol-ogy that could compromise vision in either eye. Participantswere also excluded if they had diabetes or any neurological orsystemic disease affecting vision, if they were taking anymedication known to affect retinal or visual function (e.g.,hydroxychloroquine), if they had any physical and/or mentalimpairment preventing them from participating in this study orif they were unable or did not provide written informedconsent.

Procedures

The AMD participants underwent measurements of best-corrected visual acuity monocularly after a standardizedrefraction procedure, using an Early Treatment of DiabeticRetinopathy Study (ETDRS) refraction chart at 4 m. Participantsthen performed microperimetry and then mfERG recordings.Retinal imaging and clinical examination were performed lastto minimize the potential influence of bleached photorecep-tors on the functional tests.

Microperimetry Examination

Measurements of sensitivity to luminance increment wereobtained using the Macular Integrity Assessment (MAIA;CenterVue, Padova, Italy) microperimeter, in a manner asoutlined previously.25 Firstly, pupillary dilation of at least 6 mmwas performed using 1 drop of 1% tropicamide and 1 drop of

2.5% phenylephrine. Identical verbal instructions were thengiven to all participants regarding how to perform themicroperimetry test. The MAIA microperimeter performsfundus tracking at 25 frames per second using the entirefundus as a reference. Visualization of the fundus was achievedusing a line-scanning laser ophthalmoscope (SLO), with asuper-luminescent diode illumination that has a centralwavelength of 850 nm. The fixation target is a red ring of 18diameter, and Goldman III stimuli were presented for 200milliseconds against a background of 1.27 cd/m2 using a 4-2staircase threshold strategy. The maximum and minimumluminance of the stimulus was 318 cd/m2 and 1.37 cd/m2

respectively, creating a dynamic range of 36 dB. A customizedstimulus grid (CERA AMD 68 grid) consisting of 37 pointslocated at 08, 18, 2.338, 48, and 68 from fixation was used in thisstudy, which we designed specifically for the assessment of themacular region in eyes with AMD (Fig. 1).

The frequency of false-positive responses, indicated by thefrequency of response to suprathreshold stimuli at thephysiological blind spot (manually located on the MAIA beforethe presentation of the first stimuli) was used to provide anindex of test reliability. Any examination with false-positiveresponses of greater than 25% on any examination wasexcluded, and were repeated again until the test reliabilitywas less than or equal to 25%. This cut-off was chosen becausethe MAIA presents a false-positive stimulus approximatelyevery 1 minute, and only four to five false-positive stimuli aretypically presented in each test given the short duration of theexaminations. In this study, two examinations of the right eyefollowed by at least one examination of the left eye wasperformed; the first examination was discarded to avoid thepotential influence of a learning effect as previously recom-mended.25 All participants were given approximately 3minutes of rest between each test to minimize the effect offatigue.

Multifocal Electroretinography

The recording protocol for the mfERG was performed asdescribed previously.26,27 The Visual Evoked Response ImagingSystem (VERIS Science 6; ElectroDiagnostic Imaging, Inc.,Redwood City, CA, USA) and Dawson-Trick-Litzkow (DTL)thread electrodes were used in this study. Pupillary dilationwas already performed prior to microperimetry testing, but

FIGURE 1. Microperimetry and multifocal electroretinography (mfERG) stimulus patterns used in this study and the stimuli analyzed (black filled

circles for microperimetry and gray filled hexagons for mfERG) to allow a comparison to be made with the parameters of the pathological features.The dashed circle (right) outlines the central 3-mm diameter.

The Influence of RPD on Retinal and Visual Function IOVS j March 2015 j Vol. 56 j No. 3 j 2101


pupil size was measured again prior to mfERG testing to ensurethat it was at least 7 mm in diameter. The mfERG recordingprotocol involved using 103 retinal-scaled hexagons as the teststimulus (Fig. 1), delivered using a fixation monitoring system(FMS) with a pseudorandom m-sequence (m¼ 15) set at a rateof 75 Hz. The luminance of the white hexagons was set at 5.33cd.s.m�2 and the contrast between the black and whitehexagons were approximately 99%; the background luminancewas set at 200 cd.m�2. The fixation target was a cross that was38 in diameter and 0.68 (20% of the fixation target diameter) inthickness; these parameters were chosen to provide a fixationtarget that was visible enough while maintaining minimalcoverage of the central hexagon. The recorded signal wasfiltered using a band pass filter between 10 and 100 Hz and wasamplified 100,000 times (model 12; Grass NeuroData, Quincy,MA, USA). Any segment contaminated with blinks or eyemovements were discarded and rerecorded prior to thecompletion the entire recording.

Imaging

Color fundus photographs were obtained with a Canonnonmydriatic camera (Canon CR6-45NM; Canon, Saitama,Japan). Spectral-domain optical coherence tomography (SD-OCT) raster scans were performed using the Cirrus HD-OCT(Carl Zeiss Meditec, Dublin, CA, USA) using the 200 3 200 A-scan protocol that covered 6 mm 3 6 mm centered on thefovea. Any scan where motion artifacts were present or had animage quality score of less than seven were discarded andimmediately repeated to ensure that optimal scans wereobtained. Near-infrared reflectance and fundus autofluores-cence imaging, and high-resolution line and volume SD-OCTscans were also obtained using a Spectralis HRAþOCT(Heidelberg Engineering, Heidelberg, Germany) to assist thedetection of any signs of advanced AMD; the SD-OCT volumescan was performed using 49 B-scans that covered a 208 3 208area, using the high-resolution setting and averaging 25 framesfor each B-scan.

Analysis of Pathological Features

In this study, pathological features were analyzed and gradedonly within the central 3-mm diameter in order to allowcomparisons with the functional parameters to be made incorresponding regions. Drusen volume were determined usingthe proprietary algorithm on the Cirrus HD-OCT (version 6.0;Carl Zeiss Meditec), which identified the RPE band andcomputed a virtual RPE floor, an extrapolation of the RPEgeometry in the absence of any local deformation in theband.28 The values for drusen volume within the central 3-mmdiameter (or approximately 5.28 radius) were used in this studyand a cube root transformation was applied to these values. Forpigmentary changes and RPD, the number of subfields of theETDRS grid within the central 3-mm diameter (total of fivesubfields) where these features were present was consideredas the outcome parameter. Pigmentary changes were definedwhen both hyperpigmented clumps were visible on color

fundus photography as well as hyperreflective foci (HF) visibleon SD-OCT scans29; hypopigmentary changes were notaccounted for. The presence of RPD was defined as groupsof hyporeflective lesions against a mildly hyperreflectivebackground on near infrared reflectance imaging, withcorresponding hyperreflective signals above the RPE band onSD OCT.11,12,30,31 At least five or more lesions of definite RPDwere required for RPD to be graded as being present in asubfield. In addition, all participants not considered to haveany RPD within the central 3-mm diameter were also graded todetermine if RPD were present outside this region using thesame criteria. One experienced grader performed all thegrading in this study of the right and left eye of each participantsequentially, while being masked to the results of thefunctional measures. Any uncertainty in grading was adjudi-cated with a senior retinal specialist.

Statistical Analysis

For microperimetry, luminance increment sensitivity of allpoints within the central 48 (which fell within the central 3-mm diameter) was averaged to provide a mean sensitivity (MS)value in this region. For mfERG, a summed response from thecentral two rings (corresponding to approximately the central48 radius, and consists of seven hexagons) was used and N1-P1response amplitude (density-scaled) and P1 implicit time wereused as the outcome parameters; no spatial averaging wasapplied to the mfERG data.

An independent-samples t-test was used to examine thedifference in age between participants with greater than orequal to 1 subfields with RPD in either eye, and participantswithout any RPD in either eye. Generalized estimatingequation (GEE) models were used to examine the differencein structural parameters between eyes with RPD and eyeswithout RPD, and also the association between the structuralparameters and the functional parameters. An exchangeablecorrelation structure (specifying homogenous correlationsbetween eyes) was used as the type of covariance matrix toaccount for within-subject correlations because two eyes wereused for each participant (because measurements are oftencorrelated between the two eyes), and model-based estimatesof the standard errors were used for the parameters. For theanalyses of the association between structural and functionalparameters, each structural parameter was first entered intothe model in a univariate analysis, and parameters found to bestatistically significant (P < 0.05) were then entered togetherinto another model in a multivariate analysis. All statisticalanalyses were performed using commercially available statisti-cal software (IBM SPSS Statistics, software version 21; IBM/SPSS, Inc., Chicago, IL, USA).

RESULTS

A total of 60 AMD participants (70.5 6 7.2 years, range, 51–84)with intermediate AMD (at least drusen >125 lm) in both eyes(120 eyes) were included in this study, and their characteristicsare shown in Table 1. In this study, all participants graded asnot having any subfields with RPD within the central 3-mmdiameter in this study also did not have RPD outside thisregion. Among all the participants, 18 (30%) ‡ 1 subfields withRPD in either eye; two (11%) participants had ‡ 1 subfieldswith RPD in only one eye and 16 (89%) participants had ‡ 1subfields with RPD in both eyes. Participants with ‡ 1subfields with RPD in either eye were significantly older thanparticipants who did not have any RPD (76.5 6 4.3 and 67.9 66.9 years, respectively; P < 0.001). Therefore, all the analysespresented below were also repeated when including partici-

TABLE 1. Characteristics of Eyes With and Without RPD in this Study

Parameter

RPD

(n ¼ 39)

No RPD

(n ¼ 81) P Value*

Drusen volume, mm 0.28 6 0.02 0.27 6 0.03 0.792

Presence of pigmentary

changes (eyes) 17 (44%) 35 (43%) 0.975

* Generalized Estimating Equation model analysis between RPD andno RPD.



pants of similar age to ensure that the findings were notinfluenced by the difference in age between participants withand without RPD (see Supplementary Material).

SD-OCT Parameters Associated WithMicroperimetry

The univariate analyses showed that age and all SD-OCTparameters, drusen volume, pigmentary changes, and RPD,were significantly associated with microperimetric sensitivity(P � 0.020). Combining all of these parameters in amultivariate analysis, only age, drusen volume and pigmentarychanges were significantly associated with microperimetricsensitivity (P � 0.001; Table 2), while RPD was no longersignificantly associated (P ¼ 0.068).

SD-OCT Parameters Associated With MultifocalElectroretinography

For mfERG response amplitudes, the univariate analysesshowed that age and RPD exhibited significant associations(P � 0.015), but drusen volume and pigmentary changes didnot (P ‡ 0.056). Combining those significant parameters in amultivariate analysis, neither parameter remained significantlyassociated (P ‡ 0.090; Table 3).

The univariate analyses revealed that all parameters (age,drusen volume, pigmentary changes, and RPD) exhibited asignificant association with mfERG implicit time (P � 0.020).In a multivariate analysis, all parameters still remainedsignificant (P � 0.023; Table 4). To confirm that the extentof RPD was associated with mfERG implicit time, themultivariate analysis was repeated only for eyes with RPDand the results showed that mfERG implicit time remainedsignificantly associated with the number of subfields whereRPD were present (b coefficient ¼ 0.63 6 0.20, P ¼ 0.002).

Examples of Findings in This Study

To illustrate the influence of RPD on microperimetry andmfERG parameters, two examples are shown in Figure 2 whereboth eyes have similar drusen volume and pigmentary changeswere absent in the central 3 mm for both eyes, but RPD ispresent in one eye (Fig. 2B) but not the other (Fig. 2A). Themicroperimetric sensitivity was similar between the two eyes,

but mfERG implicit time was greater in the eye with RPD (Fig.2B) compared with the first example where RPD were absent(Fig. 2A).

To further illustrate the influence of RPD and pigmentarychanges on function, two examples are shown in Figure 3 whereboth eyes have similar drusen volume in the central 3 mm. In thefirst example, RPD was present in an eye without anypigmentary changes (Fig. 3A), while the second example wascharacterized by the absence of RPD but four subfields wherepigmentary changes were present (Fig. 3B). Microperimetricsensitivity was worse in the second example with pigmentarychanges (Fig. 3B) compared with the first example where it wasabsent (Fig. 3A), but mfERG implicit time was greater in the firstexample where RPD was present (Fig. 3A) compared with thesecond example where it was absent (Fig. 3B).

DISCUSSION

Recent studies investigating the influence of RPD on retinaland visual function have examined eyes where they are presentwithout any typical drusen,18–20 allowing a targeted evaluationof this feature. However, RPD are often present in eyes withfeatures of the early stages of AMD,6–10,21,22 and have beenreported to be associated with an increased risk of progressionto advanced AMD.4–9 Thus, we sought to examine theinfluence of the presence and extent of RPD, in addition tothe features that define intermediate AMD (drusen >125 lm,with or without pigmentary abnormalities), on retinal andvisual function. In this study, we found that the presence andextent of RPD was associated with changes in mfERG implicittime, but not mfERG response amplitudes or microperimetricsensitivity, after adjusting for age and other pathologicalfeatures known to influence retinal and visual function.

The association between drusen volume and pigmentaryabnormalities with microperimetric sensitivity found in thisstudy is consistent with previous studies in early stages ofAMD.32–35 However, we did not find a significant associationbetween microperimetric sensitivity and the presence andextent of RPD. A previous study found that eyes with RPDalone had poorer retinal sensitivity than eyes with drusenalone,20 and thus we had expected the presence and extent ofRPD to have a significant influence on microperimetricsensitivity in this study. As our data showed that there was asignificant association between pigmentary changes andmicroperimetric sensitivity in eyes with AMD, it is possiblethat the presence and extent of pigmentary changes differedbetween the two groups in the previous study, which mayaccount for the difference in microperimetric sensitivityreported. It also is possible that eyes with RPD alone representa distinct phenotype with distinct pathological changes (suchas outer retinal atrophy36) not present in intermediate AMDeyes with RPD, which may account for the reduced micro-perimetric sensitivity reported.20

TABLE 2. Multivariate Analysis for Parameters Associated With Micro-perimetric Luminance Increment Sensitivity

Parameter b Coefficient

Standard

Error Wald v2 P Value

Age, per y �0.09 0.03 11.21 0.001

Drusen volume, per

mm �5.65 1.14 24.52 <0.001

Pigmentary changes,

per subfield �0.48 0.11 17.68 <0.001

RPD, per subfield �0.18 0.09 3.32 0.068

P values < 0.05 have been bolded.

TABLE 3. Multivariate Analysis for Parameters Associated With mfERGResponse Amplitudes


Standard


Age, per y �0.22 0.13 2.88 0.090

RPD, per subfield �0.75 0.49 2.29 0.130

TABLE 4. Multivariate Analysis for Parameters Associated With mfERGImplicit Time


Standard


Age, per y 0.08 0.03 8.37 0.004

Drusen volume, per

mm 3.23 1.42 5.19 0.023

Pigmentary changes,

per subfield 0.55 0.15 13.55 <0.001

RPD, per subfield 0.38 0.11 11.39 0.001

P values < 0.05 have been bolded.



In this study, we found that mfERG implicit time wasassociated with the presence and extent of RPD in intermediateAMD. However, a previous study that did not find a significantdifference in mfERG responses between areas with and withoutRPD in an eye, or between the eyes with RPD and healthyeyes,18 and thus we had not expected RPD to have a significantinfluence on the mfERG responses in this study. Such differingfindings have also been observed in mfERG findings of eyes withthe early stages of AMD within the literature, where moststudies have observed significant functional deficits comparedwith healthy eyes26,37,38 while some others have not.39,40 It hasbeen suggested these differing findings are likely attributed tothe differences in the mfERG recording system and protocolused in those studies. Similarly, the intensity of the whitehexagon of the mfERG recording protocol used in our study(5.33 cd.s.m�2) was much brighter than that used in theprevious study (2.00 cd.s.m�2),18 and may thus elicit greaterfunctional deficits and account for these discrepancies.

Although shifts in fixation may have been a limitation whenexamining the association between the pathological featuresand functional changes in the central macular region in thisstudy, we believe the techniques employed in this studyallowed these comparisons to be valid and the results of thisstudy to be relevant. Firstly, the fundus-tracking featureemployed by microperimetry allowed the specified regionswithin the central 3-mm diameter to be accurately sampledsince it compensates for fixation shifts. Secondly, the fixationmonitoring system (FMS III) used during mfERG recordingsallowed us to discard any segments contaminated by blinks oreye movements. In addition, the portion of the mfERG stimuluspattern analyzed in this study was smaller than the regionwhere the pathological features were analyzed by approxi-mately 18 in radius, and thus small fixation shifts wouldunlikely have resulted in an area outside the region analyzed tobe stimulated.

In an attempt to understand the additional influence of RPDin eyes with intermediate AMD on retinal and visual function, itis important to note that the technique of mfERG andmicroperimetry measure different aspects of function and wedid not find significant correlations between the parameters ofthese two methods in a recent study.41 Importantly, the mfERGis an electrophysiological measure of suprathreshold responsesat photopic levels and the first order kernel responses originatefrom the cone photoreceptors and bipolar cells,42 whilemicroperimetry is a psychophysical measure of luminanceincrement sensitivity at mesopic levels, which may bemediated by both rod and cone photoreceptor pathways.Additionally, measurements on microperimetry are not solelyinfluenced by the physiological condition of the retina unlikemfERG, but by the entire visual pathway. Thus, mfERG may becapturing a unique aspect of cone-mediated neuroretinaldeficits associated with RPD in eyes with intermediate AMDas observed in this study. Specifically, the association betweenthe presence and extent of RPD with mfERG implicit time, butnot response amplitude, suggests an association with neuro-retinal functional abnormalities of the cone-mediated pathwaysrather than cell loss.43 However, our findings are unable todetermine the exact mechanisms responsible for thesefunctional changes.

The findings of altered cone photoreceptor appearanceoverlying RPD visualized on AO-SLO in other recent stud-ies14–17 also supports the association between mfERG implicittime changes and the presence and extent of RPD found in thisstudy. However, these cone photoreceptor changes did notappear to have a significant influence on mesopic visualfunction, as determined on microperimetry in this study.

A recent histologic study of RPD also suggested that theirpresence may also be associated with pathophysiologicalchanges of rod photoreceptors, due to the preferentiallocalization of RPD in the perifovea, the area with the highestrod photoreceptor density.44 In this study, we did not examine

FIGURE 2. Influence of reticular pseudodrusen (RPD) on microperimetric sensitivity and mfERG implicit time. Two examples are shown whereboth eyes have similar drusen volume and pigmentary changes are absent in the central 3 mm in both eyes, but RPD is absent in one eye (A) andpresent in the other (B). The microperimetric sensitivity was similar in both eyes, but mfERG implicit time was greater in the eye with RPD (B)compared with the eye without RPD (A).



the influence of RPD on rod-mediated retinal and visualfunction and future studies are required to examine this, as wehave anecdotally observed in our clinical experience thatparticipants with RPD more frequently report symptomsassociated with dark adaptation and scotopic dysfunction,which is consistent with a recent report (Flamendorf J, et al.IOVS 2014;55: ARVO E-Abstract 5221). This will not onlyprovide further understanding into the pathological nature ofRPD, but its influence on visual function under theseconditions.

We also observed that participants with RPD were alsosignificantly older than participants without, and although wehave adjusted for age in all the multivariate analyses, we furtherconfirmed the findings of this study by analyzing participantsof similar age between the two groups. The findings from theseanalyses were consistent with those from the whole cohort,and we are thus confident that the difference in age wasappropriately accounted for in our analyses.

In conclusion, the presence and extent of RPD in eyes withintermediate AMD was independently associated with worsefunctional deficits in mfERG implicit time, but not with mfERGresponse amplitudes and on microperimetry.

Acknowledgments

Supported by the National Health and Medical Research Council(NHMRC) Project Grant (#1027624; Canberra, ACT, Australia),Macular Disease Foundation Australia (MDFA) Research Grant(Sydney, NSW, Australia), Bupa Health Foundation (Sydney, NSW,Australia), BrightFocus Foundation (Clarksburg, MD, USA), aUniversity of Melbourne Early Career Research Grant (LNA,#1350114; Parkville, VIC, Australia) and the Menzies Foundation(East Melbourne, VIC, Australia). CERA receives OperationalInfrastructure Support from the Victorian Government and issupported by a NHMRC Centre for Clinical Research ExcellenceAward (#529923).

Disclosure: Z. Wu, None; L.N. Ayton, None; G. Makeyeva, None;R.H. Guymer, None; C.D. Luu, None

References

1. Klein R, Davis MD, Magli YL, et al. The Wisconsin age-relatedmaculopathy grading system. Ophthalmology. 1991;98:1128–1134.

2. Bird AC, Bressler NM, Bressler SB, et al. An internationalclassification and grading system for age-related maculopathyand age-related macular degeneration. Surv Ophthalmol.1995;39:367–374.

3. Ferris F, Davis M, Clemons T, et al. A simplified severity scalefor age-related macular degeneration: AREDS Report No. 18.Arch Ophthalmol. 2005;123:1570–1574.

4. Hogg RE, Silva R, Staurenghi G, et al. Clinical characteristics ofreticular pseudodrusen in the fellow eye of patients withunilateral neovascular age-related macular degeneration. Oph-thalmology. 2014;121:1748–1755.

5. Pumariega NM, Smith RT, Sohrab MA, LeTien V, Souied EHA.Prospective study of reticular macular disease. Ophthalmolo-gy. 2011;118:1619–1625.

6. Finger RP, Wu Z, Luu CD, et al. Reticular pseudodrusen: a riskfactor for geographic atrophy in fellow eyes of individuals withunilateral choroidal neovascularization. Ophthalmology. 2014;121:1252–1256.

7. Joachim N, Mitchell P, Rochtchina E, Tan AG, Wang JJ.Incidence and progression of reticular drusen in age-relatedmacular degeneration: findings from an older Australiancohort. Ophthalmology. 2013;121:917–925.

8. Arnold JJ, Sarks SH, Killingsworth MC, Sarks JP. Reticularpseudodrusen: a risk factor in age-related maculopathy.Retina. 1995;15:183–191.

9. Klein R, Meuer SM, Knudtson MD, Iyengar SK, Klein BEK. Theepidemiology of retinal reticular drusen. Am J Ophthalmol.2008;145:317–326.

FIGURE 3. Influence of RPD and pigmentary changes on microperimetric sensitivity and mfERG implicit time. Two examples are shown whereboth eyes have similar drusen volume in the central 3 mm, but one eye is characterized by the presence of RPD without pigmentary changes (A),while the other eye is characterized by the presence of pigmentary changes without RPD (B). Microperimetric sensitivity was worse in the secondeye with pigmentary changes (B) compared with the eye without (A), but mfERG implicit time was greater in the first eye with RPD (A) comparedwith the eye without (B).



10. Zweifel SA, Spaide RF, Curcio CA, Malek G, Imamura Y.Reticular pseudodrusen are subretinal drusenoid deposits.Ophthalmology. 2010;117:303–312.

11. Schmitz-Valckenberg S, Steinberg JS, Fleckenstein M, et al.Combined confocal scanning laser ophthalmoscopy andspectral-domain optical coherence tomography imaging ofreticular drusen associated with age-related macular degener-ation. Ophthalmology. 2010;117:1169–1176.

12. Querques G, Querques L, Martinelli D, et al. Pathologicinsights from integrated imaging of reticular pseudodrusen inage-related macular degeneration. Retina. 2011;31:518–526.

13. Querques G, Canouı-Poitrine F, Coscas F, et al. Analysis ofprogression of reticular pseudodrusen by spectral domain–optical coherence tomography. Invest Ophthalmol Vis Sci.2012;53:1264–1270.

14. Zhang Y, Wang X, Rivero EB, et al. Photoreceptor perturbationaround subretinal drusenoid deposits revealed by adaptiveoptics scanning laser ophthalmoscopy. Am J Ophthalmol.2014;158:584–596.

15. Mrejen S, Sato T, Curcio CA, Spaide RF. Assessing the conephotoreceptor mosaic in eyes with pseudodrusen and softdrusen in vivo using adaptive optics imaging. Ophthalmology.2014;121:545–551.

16. Meadway A, Wang X, Curcio CA, Zhang Y. Microstructure ofsubretinal drusenoid deposits revealed by adaptive opticsimaging. Biomed Optics Exp. 2014;5:713–727.

17. Querques G, Kamami-Levy C, Blanco-Garavito R, et al.Appearance of medium–large drusen and reticular pseudo-drusen on adaptive optics in age-related macular degeneration.Br J Ophthalmol. 2014;98:1522–1527.

18. Alten F, Heiduschka P, Clemens CR, Eter N. Multifocalelectroretinography in eyes with reticular pseudodrusen.Invest Ophthalmol Vis Sci. 2012;53:6263–6270.

19. Ooto S, Ellabban AA, Ueda-Arakawa N, et al. Reduction ofretinal sensitivity in eyes with reticular pseudodrusen. Am JOphthalmol. 2013;156:1184–1191, e2.

20. Querques G, Massamba N, Srour M, et al. Impact of reticularpseudodrusen on retinal function. Retina. 2014;34:321–329.

21. Cohen SY, Dubois L, Tadayoni R, et al. Prevalence of reticularpseudodrusen in age-related macular degeneration with newlydiagnosed choroidal neovascularisation. Br J Ophthalmol.2007;91:354–359.

22. Lee MY, Yoon J, Ham D-I. Clinical characteristics of reticularpseudodrusen in Korean patients. Am J Ophthalmol. 2012;153:530–535.

23. Ferris FL III, Wilkinson C, Bird A, et al. Clinical classification ofage-related macular degeneration. Ophthalmology. 2013;129:844–851.

24. Wu Z, Luu CD, Ayton LN, et al. Optical coherence tomographydefined changes preceding the development of drusen-associated atrophy in age-related macular degeneration.Ophthalmology. 2014;121:2415–2422.

25. Wu Z, Ayton LN, Guymer RH, Luu CD. Intrasession test–retestvariability of microperimetry in age-related macular degener-ation. Invest Ophthalmol Vis Sci. 2013;54:7378–7385.

26. Gin TJ, Luu CD, Guymer RH. Central retinal function asmeasured by the multifocal electroretinogram and flickerperimetry in early age-related macular degeneration. InvestOphthalmol Vis Sci. 2011;52:9267–9274.

27. Wu Z, Ayton LN, Guymer RH, Luu CD. Relationship betweenthe second reflective band on optical coherence tomography

and multifocal electroretinography in age-related maculardegeneration. Invest Ophthalmol Vis Sci. 2013;54:2800–2806.

28. Gregori G, Wang F, Rosenfeld PJ, et al. Spectral domain opticalcoherence tomography imaging of drusen in nonexudativeage-related macular degeneration. Ophthalmology. 2011;118:1373–1379.

29. Folgar FA, Chow JH, Farsiu S, et al. Spatial correlation betweenhyperpigmentary changes on color fundus photography andhyperreflective foci on SDOCT in intermediate AMD. InvestOphthalmol Vis Sci. 2012;53:4626–4633.

30. Smith RT, Sohrab MA, Busuioc M, Barile G. Reticular maculardisease. Am J Ophthalmol. 2009;148:733–743.

31. Ueda-Arakawa N, Ooto S, Tsujikawa A, et al. Sensitivity andspecificity of detecting reticular pseudodrusen in multimodalimaging in Japanese patients. Retina. 2013;33:490–497.

32. Midena E, Vujosevic S, Convento E, Cavarzeran F, Pilotto E.Microperimetry and fundus autofluorescence in patients withearly age-related macular degeneration. Br J Ophthalmol.2007;91:1499–1503.

33. Hartmann KI, Bartsch DUG, Cheng L, et al. Scanning laserophthalmoscope imaging stabilized microperimetry in dry age-related macular degeneration. Retina. 2011;31:1323–1331.

34. Acton JH, Smith RT, Hood DC, Greenstein VC. Relationshipbetween retinal layer thickness and the visual field in early age-related macular degeneration. Invest Ophthalmol Vis Sci.2012;53:7618–7624.

35. Wu Z, Ayton LN, Luu CD, Guymer RH. Relationship betweenretinal microstructures on optical coherence tomography andmicroperimetry in age-related macular degeneration. Ophthal-mology. 2014;121:1445–1452.

36. Spaide RF. Outer retinal atrophy after regression of subretinaldrusenoid deposits as a newly recognized form of late age-related macular degeneration. Retina. 2013;33:1300–1308.

37. Gerth C, Hauser D, Delahunt PB, Morse LS, Werner JS.Assessment of multifocal electroretinogram abnormalities andtheir relation to morphologic characteristics in patients withlarge drusen. Arch Ophthalmol. 2003;121:1404–1414.

38. Parisi V, Perillo L, Tedeschi M, et al. Macular function in eyeswith early age-related macular degeneration with or withoutcontralateral late age-related macular degeneration. Retina.2007;27:879–890.

39. Feigl B, Brown B, Love-Kitchin J, Swann P. Cone- and rod-mediated multifocal electroretinogram in early age-relatedmaculopathy. Eye. 2005;19:431–441.

40. Feigl B, Brown B, Lovie-Kitchin J, Swann P. Cone-mediatedmultifocal electroretinogram in early age-related maculopathyand its relationships with subjective macular function tests.Curr Eye Res. 2004;29:327–336.

41. Wu Z, Ayton LN, Guymer RH, Luu CD. Comparison ofmultifocal electroretinography and microperimetry in age-related macular degeneration. Invest Ophthalmol Vis Sci.2014;55:6431–6439.

42. Hood DC, Frishman LJ, Saszik S, Viswanathan S. Retinal originsof the primate multifocal ERG: implications for the humanresponse. Invest Ophthalmol Vis Sci. 2002;43:1673–1685.

43. Hood DC. Assessing retinal function with the multifocaltechnique. Prog Retin Eye Res. 2000;19:607–646.

44. Curcio CA, Messinger JD, Sloan KR, et al. Subretinal drusenoiddeposits in non-neovacular age-related macular degeneration:morphology, prevalence, topography, and biogenesis model.Retina. 2013;33:265–276.



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Impact of Reticular Pseudodrusen on Microperimetry and ... · Color fundus photographs were obtained with a Canon nonmydriatic camera (Canon CR6-45NM; Canon, Saitama, Japan). Spectral-domain