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sound.2,3 As OCT facilitates the detection of very early stages ofVD,4,5 we found a substantially higher postoperative PVD rate

than was previously reported using biomicroscopy and ultra-sound only.2,3 In addition, OCT disclosed significant dynamicsof the vitreoretinal interface changes in the postoperative course.

OCT essentially extended our knowledge about PVD.5 AsDrs Yepez and Arevalo mentioned in their correspondence,anterior vitreous detachment (AVD) is another strikingoccurrence after cataract surgery, playing an important role inpseudophakic retinal detachment. According to Dr Yepez(Yepez JB, unpublished data, May 2010), a considerableamount of fluid passes from the anterior chamber through thezonules and consequently leads to hydrodissection of theanterior hyaloid. This mechanism can be demonstrated withmagnetic resonance imaging after gadolinium-assisted phaco-emulsification and with ultrasound biomicroscopy. Thesepreliminary results substantially contribute to our understand-ing of the pathophysiology of the pseudophakic retinal detach-ment. We strongly encourage further investigation on this topic.

DOMAGOJ IVASTINOVIC

ANDREAS WEDRICH

MICHAELA VELIKAY-PAREL

Graz, Austria

CONFLICT OF INTEREST DISCLOSURES: SEE THE ORIGINALarticle1 for any disclosures of the authors.

REFERENCES

1. Ivastinovic D, Schwab C, Borkenstein A, Lackner EM,Wedrich A, Velikay-Parel M. Evolution of early changes atthe vitreoretinal interface after cataract surgery determined byoptical coherence tomography and ultrasonography. Am JOphthalmol 2012;153(4):705–709.

2. Mirshahi A, Hoehn F, Lorenz K, Hattenbach LO. Incidence ofposterior vitreous detachment after cataract surgery. J CataractRefract Surg 2009;35(6):987–991.

3. Ripandelli G, Coppé AM, Parisi V, et al. Posterior vitreousdetachment and retinal detachment after cataract surgery.Ophthalmology 2007;114(4):692–697.

4. Hoehn F, Mirshahi A, Hattenbach LO. Optical coherencetomography for diagnosis of posterior vitreous detachment atthe macular region. Eur J Ophthalmol 2009;19(3):442–447.

5. Uchino E, Uemura A, Ohba N. Initial stages of posteriorvitreous detachment in healthy eyes of older persons evaluatedby optical coherence tomography. Arch Ophthalmol2001;119(10):1475–1479.

Longitudinal Study of Macular Foldsby Spectral-domain OpticalCoherence Tomography

EDITOR:

WE READ WITH INTEREST DR WONG’S ARTICLE ENTITLED

“Longitudinal study of macular folds by spectral-domain o

CORRESPONVOL. 154, NO. 4

optical coherence tomography.”1 In this study 10 patientsoperated on for rhegmatogenous retinal detachment (RD)and showing retinal folds postoperatively are prospectivelyfollowed. On the basis of color fundus photography andoptical coherence tomography (OCT), 3 patterns of mac-ular folds are identified: “ripple” (7 patients), “taco” (2patients), and “displacement” (1 patient) folds.

There are some aspects of the study on which we wouldlike to comment.

Dr Wong does not provide information regarding thescheduled follow-up visits and the OCT protocol used torecord the images. These are important aspects becausethey can affect the interpretation of the clinical data andOCT findings, making the conclusions weak or unreliable.

According to the author description, ripple and tacofolds share several characteristics, the ripple essentiallydiffering from the taco by the larger size on OCT and by awhite line running along the fold discernible on ophthal-moscopy. However, it has been recently shown that,depending on OCT sections (transverse, axial, or obliqueto the main axis of the fold), the scanned folds may appearvariable both in shape (round, mushroom-like, trampo-line-like) and in size.2 Ideally, only transverse scans (per-pendicular to the main axis of the folds) should beconsidered when making comparisons.

Furthermore, our experience is that on careful fundu-scopic examination, subtle retinal folds (corresponding toripple folds on OCT) also appear as white-yellow lines.

Both ripple and taco folds tend to resolve spontaneouslyover time. It is possible that some ripple folds scanned afew months after operation were taco in the immediatepostoperative period. Considering that ripple and tacofolds are not associated with peculiar symptoms or differentpathogenesis, distinguishing between the two could beunnecessary.

The third recognized pattern, observed in only 1 patientcomplaining of postoperative binocular diplopia, is named“displacement fold.” The term displacement fold does notappear appropriate for 2 reasons. First, unintentional dis-placement of the retina may be involved in ripple and tacofold formation as well. In fact, it is not the fold that causesthe displacement but the displacement that causes thefold.3,4 Second, the translocation may persist despite theresolution of the fold.

Unintentional retinal translocation occurring after RDrepair is elegantly visualized using fundus autofluorescence(FAF).5 Concomitant presence of retinal translocationnd small partial-thickness retinal folds, using simultane-us OCT-FAF imaging, has been described.2 Dr Wong didot record FAF, so it cannot be excluded that even theases showing ripple or taco folds in his series presentedith associated retinal translocation.The author proposes that in case of a displacement fold,

edetachment of the retina or extraocular muscle surgery maye advisable. In our opinion, the degree of translocation and

f the resulting binocular diplopia (not evaluable either with

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funduscopy or with OCT), instead of the mere presence of afold (not showing any pathognomonic feature and potentiallyresolving without treatment), should be regarded as anindication for further surgery.

ROBERTO DELL’OMO

CIRO COSTAGLIOLA

Campobasso, Italy

CONFLICT OF INTEREST DISCLOSURES: THE AUTHORShave completed and submitted the ICMJE Form for Disclosure ofPotential Conflicts of Interest and none were reported.

REFERENCES

1. Wong R. Longitudinal study of macular folds by spectral-domain optical coherence tomography. Am J Ophthalmol2012;153(1):88–92.

2. dell’Omo R, Mura M, Lesnik Oberstein SY, Bijl HM, Tan HS.Early simultaneous fundus autofluorescence and optical coher-ence tomography features after pars plana vitrectomy forprimary rhegmatogenous retinal detachment. Retina 2012;32(4):719–728.

3. Lewis H, Kaiser PK, Lewis S, Estafanous M. Macular translo-cation for subfoveal choroidal neovascularization in age re-lated macular degeneration: a prospective study. Am JOphthalmol 1999;128(2):135–146.

4. Heimann H, Bopp S. Retinal folds following retinal detach-ment surgery. Ophthalmologica 2011;226(Suppl 1):18–26.

. Shiragami C, Shiraga F, Yamaji H, et al. Unintentionaldisplacement of the retina after standard vitrectomy forrhegmatogenous retinal detachment. Ophthalmology2010;117(1):86–92.

REPLY

I WOULD LIKE TO THANK DR DELL’OMO AND DR COSTAGLI-

ola for their interest in my article.1 To clarify the scanningprotocol, this study was performed using serial spectral-domain optical coherence tomography (SD-OCT) imageswith the Topcon 3D OCT 1000 (Tokyo, Japan). The 3Dmacula protocol was used for all scans, which generate 5 to6 �m of longitudinal resolution and 20 �m of horizontalresolutions at 18 000 A-scans per second in a 6 mm by 6mm grid (512 � 128 pixels resolution). These were all

orizontal in orientation and no fold was along thecanning plane, and therefore there was enough detail toistinguish between types of folds without having the scanserpendicular to the fold as suggested.Furthermore, the first OCTs were performed 6 to 8

eeks following the surgery when all gas had dissipated.he following OCTs were taken on each follow-up, whichccurred at least 6 months and 12 months after the initialperation. The objective of this study was to illustrate theatural history of different types of folds by OCT. There-

ore, Figures 1 and 4 clearly describe the times at which

these folds were scanned. Identification of types of folds

AMERICAN JOURNAL OF758

was done at the 6- to 8-week postoperative visit and notany later, which makes it unlikely that the ripple foldpatients were patients who had resolved taco folds.

I hypothesize that a taco fold occurs only at the junctionof attached and detached retina where the weight of thesubretinal fluid almost causes the retina to hang over theattached retina. These folds are thus more prominent, andlarge outer segment lesions are formed. This effect is sosevere that it can cause a rosette configuration, as seen inFigure 5 of the manuscript.1 Ripple folds are more commonand can occur throughout the area of detachment. Theseoccur as the retina has initially stretched because of thedetachment, but folds have been created because of redun-dancy. Therefore, ripple and taco folds have a differentconfiguration and etiology.

Drs dell’Omo and Costagliola do not agree with thename “displacement fold” because displacement is seen inmany retinal detachments, as described first by Shiragamiand associates2 in their study using autofluorescence. I

ave no doubt that it occurs in taco folds as more retinalissue is involved, and therefore one can postulate thatore displacement occurs in tacos compared to ripples.However, displacement measured by autofluorescence is

lso not an exact science, and the theory of why the imagesccur is hypothetical. My colleagues at St. Thomas’ Hospitalave looked at over 80 consecutive cases of retinal detach-ents with postoperative autofluorescence (Edward Lee, per-

onal communication, 20 May 2012). Not all macula-offetinal detachments showed evidence of translocation onutofluorescence, and even some macula-on patients hadisplacement of the autofluorescent shadows correspondingo blood vessels. My definition of a “displacement fold”escribes usually an inferior retinal taco fold where there is alear shift of the fovea noticeable without the use of auto-uorescence, giving patients intractable binocular diplopia,hich is not seen in either taco or ripple folds. This hasothing to do with the fact that the fold causes the displace-ent or the displacement causes the fold, but rather that both

he displacement and fold are present.Finally, in the methods section, 5 patients were ex-

luded because they had received further surgical interven-ion. Two patients had displacement folds that weree-detached and allowed to reattach, but there was noesolution of their diplopia. Therefore, the suggestion ofhe degree of translocation and resulting diplopia beingmenable to surgical intervention is premature. Perhapsxtraocular muscle transposition is a means for improvinghe patients’ symptoms, but sensory factors such as ani-eikonia may hinder the ability to fuse the images. Unlikeetinal translocation surgery for wet age-related macularegeneration, most patients have good vision in theontralateral eye, and therefore diplopia may persist de-pite extraocular muscle surgery.

ROGER WONG

CATHERINE HOWARD

London, United Kingdom

OPHTHALMOLOGY OCTOBER 2012