Research Article Ocular Surface Epithelial Thickness ... · biomicroscopic examination and ocular...

Research ArticleOcular Surface Epithelial Thickness Evaluation inDry Eye Patients Clinical Correlations

Qingfeng Liang1 Hong Liang1234 Hanruo Liu1 Zhiqiang Pan1

Christophe Baudouin23456 and Antoine Labbeacute123456

1Beijing Institute of Ophthalmology Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical UniversityBeijing Key Laboratory of Ophthalmology and Visual Sciences Beijing 100005 China2INSERM U968 75012 Paris France3UPMC Universite Paris 06 UMR S 968 Institut de la Vision 75012 Paris France4CNRS UMR 7210 75012 Paris France5Quinze-Vingts National Ophthalmology Hospital 75012 Paris France6Versailles Saint-Quentin-en-Yvelines University 78000 Versailles France

Correspondence should be addressed to Qingfeng Liang lqflucky163com

Received 31 October 2015 Revised 31 December 2015 Accepted 31 December 2015

Academic Editor Taras Ardan

Copyright copy 2016 Qingfeng Liang et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Purpose To evaluate the relationship between corneal and conjunctival epithelium thickness and ocular surface clinical tests indry eye disease (DED) patients Patients and Methods Fifty-four patients with DED and 32 control subjects were included Eachpatient underwent an ocular surface evaluation using the ocular surface disease index (OSDI) tear film break-up time (TBUT)corneal and conjunctival staining tear film lipid layer analysis and Schirmer test The central corneal (CET) limbal (LET) andbulbar conjunctival epithelium thickness (BET) were acquired using spectral-domain optical coherence tomography (SD-OCT)ResultsCompared to control subjects mean BETwas significantly thicker andmean LETwas significantly lower in the DED groupThere was no significant difference in mean CET between the two groups The mean LET was correlated with OSDI and TBUTThe inferior LET was correlated with OSDI Schirmer I test TBUT Oxford score and corneal sensitivity Mean BET was correlatedwith OSDI and TBUT but not with Schirmer I test and Oxford score Conclusions In dry eye patients a thinner limbal epitheliumand a thicker bulbar conjunctival epitheliumwere observedThese changes were correlated to the severity of dry eye symptoms andtear film alterations

1 Introduction

Dry eye disease (DED) is a multifactorial disease of thetears and ocular surface resulting in tear film instabilitywith potential damage to conjunctival and corneal epithelium[1] It results from a disturbance of the lacrimal functionalunit that includes the tear film the lacrimal and meibomianglands the ocular surface epithelium and the sensory andmotor nerves that connect them [2] Inflammation withinflammatory cell infiltration and cytokine production arealso common features of DED found in the lacrimal glandsthe cornea and the conjunctiva [3] In association with themechanical and desiccating stress induced by the lack andor

the poor quality of tears inflammation further damagesocular surface epithelia Considering the central role of thesetissues in the pathophysiology of DED several imagingtechniques have been developed to evaluate and grade thealterations of ocular surface epithelia in vivo [4 5] Despitelower resolution than in vivo confocal microscopy (IVCM)SD-OCT has numerous advantages over other imaging tech-niques such as slit-lamp or ultrasound biomicroscopy [6]OCT is a noninvasive imaging method that allows high-resolution analysis and quantification without the need forocular anesthesia or contact procedures In a preliminarystudy we used SD-OCT to noninvasively evaluate ocularsurface epithelial thickness [4] In DED patients and patients

Hindawi Publishing CorporationJournal of OphthalmologyVolume 2016 Article ID 1628469 8 pageshttpdxdoiorg10115520161628469

2 Journal of Ophthalmology

using IOP-lowering eye drops we observed a decreasedlimbal-conjunctival epithelial thickness and an increased bul-bar conjunctival epithelial thickness The epithelial thicknessmeasurement of ocular surface tissues with SD-OCT seemedto be an advantageous new parameter during ocular surfaceevaluation However the number of patients in each groupwas limited and correlations were not evaluated betweenepithelium thickness changes and ocular surface clinical testsThus the objective of the present study was to comparethe results of corneal limbal and conjunctival epitheliumthicknesses obtained with SD-OCT in normal subjects andnon-Sjogren dry eye patients and to evaluate the relationshipbetween these parameters and the results of ocular surfaceclinical tests

2 Patients and Methods

21 Subjects This studywas conducted at the Beijing Instituteof Ophthalmology with approval of the Medical EthicsCommittee of BeijingTongrenHospital (TREC-2013-KY012)All patients were informed of the aims of the study andtheir consent was obtained according to the declaration ofHelsinki A total of 54 patients with DED not associatedwith Sjogren syndrome (36 women and 18 men mean age4459 plusmn 1008 years range 24ndash68 years) were consecutivelyrecruited from the Cornea Unit of Beijing Tongren Hospitalfrom June 2013 to February 2014 (DED group) The samplesize was calculated according to the results of Cui et alrsquos study[7] with 80 power level DED was defined as Schirmer Itesting lt5mm andor tear film break-up time (TBUT) lt10 saccompanied by complaints of ocular irritation in the absenceof other ocular (in particular meibomian gland disease) orsystemic diseases [1] Thirty-two age- and gender-matchedcontrol subjects (20 women and 12 men mean age 4334 plusmn1081 years range 19ndash67 years) were also recruited (controlgroup) All control subjects had no complaint of ocularsurface irritation and no anterior segment abnormality onbiomicroscopic examination and ocular surface tests Exclu-sion criteria for both groups were as follows age lt18 yearssubject unable to complete the questionnaire or understandthe procedures the presence of ocular or systemic disease orthe use of topical or systemic medications that may affect thecornea and the ocular surface (except the use of nonpreservedtear substitutes in the DED group) and previous eye surgeryor contact lens wear

22 Clinical Evaluation Demographic information andmedical history were obtained from the patientsrsquo medicalrecords Each subject underwent quantification of ocular sur-face symptomswith theOcular SurfaceDisease Index (OSDI)questionnaire (range 0ndash100) Then the subjects underwentocular surface examinations in the following order tear filmbreak-up time (TBUT) corneal and conjunctival fluoresceinstaining tear film lipid layer analysis Schirmer test withoutanesthesia and corneal sensationmeasured with the Cochet-Bonnet esthesiometer

TBUT was measured by instilling fluorescein into theinferior cul-de-sac and calculating the average of three con-secutive break-up times Corneal and conjunctival staining

was evaluated under a yellow filter using the Oxford scaleand after instillation of fluorescein Tear film lipid layeranalysis was performed using interferometry (DR-1 KowaTokyo Japan) and evaluated semiquantitatively from 1 to5 (grade 5 being the most severe) [5] Schirmer I test wasperformedwithout anesthesia for 5minwith the patientrsquos eyesclosed Corneal sensation was measured using the contactnylon thread Luneau 12100mmCochet-Bonnet esthesiome-ter (Luneau Prunay-Le-Gillon France) in the central corneaand in the superior inferior nasal and temporal quadrantsMean corneal sensitivity (MCS) was defined as the mean ofthe measures obtained in the five different areas

23 SD-OCT Examination and Image Analysis SD-OCT fit-ted with an anterior segment module (Optovue CorporationFremont CA USA) was used This SD-OCT has a scan rateof 26000 axial scans per second Its axial and transverseoptical resolution were 5 120583mand 15 120583m respectively An add-on lens (CAM-L mode 60ndash20mm) was used to assess theregional corneal and conjunctival architecture and epithelialthickness Because SD-OCT examination is a noncontacttechnique it was performed before ophthalmological exami-nations in order to avoid potential epithelium alterations

The specific imaging capture technique for this study hasbeen previously described [4] Briefly patients were asked tofixate on the target light source and consecutive images wereacquired with the patientrsquos forehead and chin stabilized bya headrest Corneal epithelium thickness (CET) was definedas the epithelium thickness in the 2mm central zone of thecornea limbal epithelium thickness (LET) was defined as thelimbal-conjunctival epithelium thickness in each quadrant(superior inferior temporal and nasal) bulbar conjunctivalepithelial thickness (BET) was defined as the bulbar conjunc-tival epithelial thickness located between 2 and 3mm fromthe limbus of each quadrant (Figure 1)

The cursors were placed perpendicular to the ocularsurface epithelium from a point located just beneath thetear film (first hyperreflective layer) to the basal membrane(second hyperreflective layer) For every quadrant threemeasurements were taken (if the difference between mea-surements exceeded 3 120583m the measurement was repeatedin order to confirm thickness measurement reproducibilitythe measurement needed to be confirmed in less than 5of cases) and the results were expressed as mean plusmn SDThe measurements were taken by one researcher (HL) whowas masked to patient demographic data and the resultsof ophthalmologic examinations To evaluate interobservervariability a second examiner (QL) who was masked to theresults of the first SD-OCT analyses assessed CET LET andBET from the same images of 20 randomized patients

24 Statistical Analysis Statistical analyses were performedwith SPSS for Windows version 160 (SPSS Inc Chicago ILUSA) For each patient one eye was randomly chosen forstatistical analysis The mean plusmn SD values of each epithelialthickness variable were calculated for both the DED andcontrol groups To compare ocular surface parameters andepithelial thickness measured in normal and DED eyestwo-tailed Studentrsquos 119905-tests were performed The Pearson

Journal of Ophthalmology 3

47120583m 44120583m 41120583m

(a)

44120583m 47120583m 44120583m

(b)

81120583m90120583m

87120583m

(c)

66120583m75120583m60120583m

(d)

43120583m44120583m46120583m

(e)

47120583m 46120583m 51120583m

(f)

Figure 1 SD-OCT images of ocular surface epithelial thickness measurement in a healthy control subject (a c e) and a dry eye patient (b df) Corneal epithelium thickness measurement with software cursors (a b) limbus and conjunctiva epithelium thickness analysis (c d) andconjunctiva epithelium thickness measurement (e f)

correlation coefficientwas used inDEDpatients to investigatethe correlation between the quantitative measurements ofepithelial thicknesses and the results of other ocular surfaceevaluations 119875 values less than 005 were considered statisti-cally significant

3 Results

There was no difference in terms of gender (119875 = 0699)and age (119875 = 0503) between the DED and control groupsConcerning ocular surface clinical evaluation DED patientshad significantly more symptoms (OSDI) (3546 plusmn 1494versus 152 plusmn 396 119875 lt 0001) lower TBUT (467 plusmn 230 sversus 1331plusmn254 s 119875 lt 0001) a lower Schirmer I test score(411 plusmn 698mm versus 1256 plusmn 699mm 119875 lt 0001) anda higher Oxford score (106 plusmn 173 versus 000 119875 = 0001)as compared to the control group Mean corneal sensitivitywas significantly decreased in theDEDgroup (574plusmn041mmversus 598 plusmn 007mm 119875 = 0002) while tear film lipid layerinterferometry was not statistically different between the twogroups (243plusmn071mmversus 228plusmn052 119875 = 0323) Resultsof clinical data are presented in Table 1

Mean CET LET and BET were 5023 plusmn 442 120583m 8137 plusmn621 120583m and 5044 plusmn 525 120583m in the DED group and 4976 plusmn315 120583m 8714 plusmn 998 120583m and 4462 plusmn 504 120583m in the controlgroup respectively Compared to control subjects mean BETwas significantly thicker (119875 lt 0001) and mean LET wassignificantly lower (119875 = 0009) in the DED group There wasno significant difference in CET between the two groups (119875 =0103) In addition dry eyes had a significantly thicker BETin each quadrant region (superior 119875 = 0005 inferior 119875 =0014 temporal 119875 lt 0001 and nasal 119875 = 0003) than thatof normal subjects In dry eyes the LET was also significantlythinner in the inferior (119875 = 0011) temporal (119875 = 0008)and nasal regions (119875 lt 0001) but not in the superiorregion (119875 = 0152) as compared to control subjects (Table 2Figure 2)

Within theDEDgroup therewere significant correlationsbetween symptoms (OSDI) and Schirmer I test (119903 = minus0312119875 = 0003) TBUT (119903 = minus0720 119875 lt 0001) and Oxfordscore (119903 = 0340 119875 = 0001) TBUT was also correlated withSchirmer I test and Oxford score (119903 = 0436 119875 lt 0001 and119903 = minus0504 119875 lt 0001 resp) Tear film lipid layer interfer-ometry was correlated with TBUT Oxford score and MCS


Table 1 Demographic and clinical test results

Parameters DED group Control group 119875valueNumber of patients 54 32Gender

Female 36 (667) 20 (625) 0699Male 18 (333) 12 (375)

Age (years) 4459 plusmn 1008 4334 plusmn 1081 0503OSDI 3546 plusmn 1494 152 plusmn 396 lt0001Schirmer I test (mm) 411 plusmn 698 1256 plusmn 699 lt0001TBUT (seconds) 467 plusmn 230 1331 plusmn 254 lt0001Oxford scale 106 plusmn 173 000 plusmn 000 0001MCS (mm) 574 plusmn 041 598 plusmn 007 0002TFL 243 plusmn 071 228 plusmn 052 0323DED dry eye disease OSDI Ocular Surface Disease Index TBUT tear film break-up time MCS mean corneal sensitivity TFL tear film lipid layerinterferometry

Table 2 Comparison of ocular surface epithelium thickness (120583m) between DED and control groups

Parameters DED group Control group 119875 valueNumber of patients 54 32CET 5023 plusmn 442 4976 plusmn 315 0103LET 8137 plusmn 621 8714 plusmn 998 0009

LET (N) 8060 plusmn 927 8995 plusmn 1523 lt0001LET (T) 8073 plusmn 891 8765 plusmn 1119 0008LET (S) 8210 plusmn 848 8464 plusmn 675 0152LET (I) 8012 plusmn 784 8674 plusmn 1445 0011

BET 5044 plusmn 525 4462 plusmn 504 lt0001BET (N) 5099 plusmn 526 4345 plusmn 499 0003BET (T) 5037 plusmn 614 4257 plusmn 500 lt0001BET (S) 5010 plusmn 513 4399 plusmn 554 0005BET (I) 5135 plusmn 527 4648 plusmn 883 0014

CET corneal epithelium thickness LET limbal epithelium thickness BET bulbar conjunctival epithelium thickness N nasal T temporal S superior Iinferior

998771

lowast

lowast

Thic

knes

s (120583

m)

110

100

90

80

70

60

50

40

30

20

4796

8714

4462

CET

ControlDED

LET BET

5023

8137

5044

Figure 2 Comparison of CET LET and BET data between DEDand control group lowast represents a significant difference between theindicated groups 119875 le 005 998771 represents no significant differenceANOVA with Tukeyrsquos post hoc test

(119903 = minus0236 119875 = 0029 119903 = minus0389 119875 lt 0001 and 119903 = 0259119875 = 0016 resp) (Table 3)

When evaluating the relationship between dry eye clinicaltests and ocular surface epithelium thickness parametersmean BET was correlated with OSDI (119903 = 0362 119875 lt 0001)and TBUT (119903 = minus0428 119875 lt 0001) but not with Schirmer Itest (119903 = minus0165 119875 = 0290) and Oxford score (119903 = 0134 119875 =0392) The mean LET was correlated with OSDI and TBUT(119903 = minus0305 119875 = 0047 and 119903 = 0378 119875 = 0012 resp)Interestingly the inferior quadrant LET was correlated withOSDI (119903 = minus0519 119875 lt 0001) Schirmer I test (119903 = 0271119875 = 0012) TBUT (119903 = 0638 119875 lt 0001) Oxford score(119903 = minus0256 119875 = 0017) and MCS (119903 = minus0519 119875 lt 0001)(Table 4)

4 Discussion

Several studies have been conducted to measure the thick-ness and morphology of ocular surface epithelium withOCT IVCM or ultrasound in order to better understand


Table 3 Statistical results of correlations between dry eye clinical tests

Parameters Gender Age OSDI Schirmer 1 test TBUT Oxford scale MCSAge119903 0162119875 0136

OSDI119903 minus0048 0071119875 0659 0514

Schirmer 1 test119903 minus0098 minus0192 minus0312

119875 0371 0077 0003TBUT119903 minus0025 minus0201 minus0720 0436119875 0817 0063 lt0001 lt0001

Oxford scale119903 0105 0098 0340 minus0274 minus0504

119875 0337 0370 0001 0011 lt0001MCS119903 minus0155 minus0177 minus0137 0111 0211 minus0185

119875 0155 0103 0209 0309 0054 0089TFL119903 0044 0053 0163 minus0207 minus0236 minus0389 0259119875 0689 0630 0134 0056 0029 lt0001 0016

DED dry eye disease OSDI Ocular Surface Disease Index TBUT tear film break-up time MCS mean corneal sensitivity TFL tear film lipid layerinterferometry

epithelial alterations in DED [7ndash13] With Fourier-domainOCT Cui et al evaluated for the first time the featuresof the corneal epithelial thickness map within the central5mm zone and the correlation with symptoms in dry eyepatients [7] Yang et al [14] and our group [4] reported theevaluationwith SD-OCTof ocular surface epithelia includingthe bulbar conjunctival epithelium the limbal epitheliumand the central corneal epithelium thicknesses in normalsubjects and dry eye patients However no studies reportedthe correlations between DED clinical features and ocularsurface epithelial thicknesses including the limbal and theconjunctival epithelium In accordance with our previousresults [4] we observed a thinner limbal epithelium anda thicker conjunctival epithelium in patients with dry eyeMoreover we observed that the severities of symptoms(OSDI) and tear film alterations (TBUT) were correlated toboth LET and BET

When evaluating the CET of DED patients some authorsobserved a decrease while others found no change or evenan increase as compared with the control group [4 7 815] Comparison between studies was made difficult by thedifferent durations and severities of the disease the varyingages of DED patients and the different techniques usedto measure CET Fabiani et al [15] established a mousemodel of dry eye and detected that the average CET becamesignificantly thicker in dry eye mice as compared to thecontrols after 7 days These results demonstrated that theinflammatory processes and epithelial proliferation had asignificant impact on the average CET in the early stage of

DEDThe studies fromChen et al [16] andKanellopoulos andAsimellis [17] indicated that increased epithelial thicknessmight be used as an objective clinical indicator of dry eyeConversely Cui et al [7] found that the superior cornealepithelium was thinner in DED patients than in normalsubjects Erdelyi et al [18] and Villani et al [19] also showedthat the CET tends to be thinner in DED patients which wasattributed to the destruction of stem cells at the limbus Inthe present study there was no significant difference in CETbetween DED patients and the control group consistent withour previous results [4] and the results from Tuominen et al[20] This may be explained by the moderate severity of DED(average OSDI 3546 and TBUT 467 s) and the location ofCET evaluation in the central cornea (central 2mm diameterarea) away from the limbus

Considering the role of limbal epithelial stem cells(LESCs) in corneal epitheliumhomeostasis the limbal regionis essential in dry eye physiopathology [21] Several factorsmight explain the reduced thickness of the limbal epitheliumin DED First stem cell metabolism can be directly affectedin DED patients [22ndash24] Infiltration of CD4+ T cells at thelimbus and the levels of inflammatory cytokines in tearsmay play an important role in inhibiting corneoscleral stemcell metabolism in dry eye patients This downregulationof limbal stem cells in DED patients could influence thedevelopment of corneal limbal epithelial layers and resultin a thinner LET Increased turnover of corneal epithelialcells might also explain limbal epithelial cell depletion inDED [4] Limbalmicroenvironment inflammation could also


Table 4 Correlations of ocular surface epithelial thickness with the result of clinical tests in the DED group

Parameters Gender Age OSDI Schirmer I test TBUT Oxford scale MCS TFLCET119903 0079 0036 0047 minus0109 minus0087 minus0104 minus0034 0003119875 0468 0743 0668 0318 0424 0342 0755 0975

LET119903 minus0178 minus0105 minus0305 0263 0378 minus0154 0113 minus0081

119875 0252 0504 0047 0089 0012 0325 0469 0607LET (nasal)119903 minus0043 minus0137 minus0322 0209 0311 minus0114 0112 0000119875 0694 0182 0022 0054 0004 0295 0304 0999

LET (temporal)119903 minus0150 0162 minus0169 0059 0280 0062 0003 minus0004

119875 0167 0135 0119 0592 0009 0573 0976 0968LET (superior)119903 minus0001 minus0103 0009 0198 0101 0105 0054 minus0043

119875 0995 0343 0933 0067 0354 0335 0623 0694LET (inferior)119903 0054 0006 minus0519 0271 0638 minus0256 0273 minus0066

119875 0429 0953 lt0001 0012 lt0001 0017 0011 0548BET119903 0157 0085 0362 minus0165 minus0428 0134 minus0178 minus0105

119875 0314 0588 lt0001 0290 lt0001 0392 0252 0504BET (nasal)119903 0041 0053 0452 minus0116 minus0500 0130 minus0105 minus0026

119875 0705 0627 lt0001 0254 lt0001 0233 0334 0815BET (temporal)119903 0023 0295 0497 minus0153 minus0479 0132 minus0152 0069119875 0833 0006 lt0001 0326 lt0001 0225 0319 0529

BET (superior)119903 0097 0060 0384 minus0075 minus0410 0118 minus0286 minus0010

119875 0372 0581 lt0001 0493 lt0001 0280 0063 0930BET (inferior)119903 0191 minus0027 0281 minus0049 minus0288 0092 minus0184 0097119875 0078 0807 0009 0651 0007 0401 0089 0376

DED dry eye disease OSDI Ocular Surface Disease Index TBUT tear film break-up time MCS mean corneal sensitivity TFL tear film lipid layerinterferometry CET corneal epithelium thickness LET limbal epithelium thickness BET bulbar conjunctival epithelium thickness

directly alter limbal stem cells and their functions resulting invarious degrees of stem cell deficiency [25] The inferior andsuperior limbal areas are thought to be the largest reservoirsof limbal stem cells as compared to the nasal and temporalquadrants With confocal microscopy and scanning electronmicroscopy Shortt et al [26] showed more limbal crypts inthe superior and inferior limbal regions Similarly Thoft etal found a larger number of stem cells in the superior andinferior limbus than in the medial and lateral areas [27]Interestingly in the present study the inferior LET seemed tobe the most sensitive parameter because it was directly corre-lated to the OSDI the Schirmer test TBUT the Oxford scoreand mean corneal sensitivity The greatest changes observedfor the inferior LET could be explained by the prolongedcontact between epithelial cells and altered tears within theinferior lacrimal river containing inflammatory factors such

as cellular debris or proinflammatory cytokines Decreasedcorneal sensitivity correlated to the inferior LET was alsoobserved in DED patients Corneal nerves are implicatedin DED pathophysiology and DED patients exhibit nervesalterations [5] These nerves changes have been correlated tothe severity of the ocular surface lesions and might be in partresponsible for corneal sensitivity alterations As observedwith corneal nerves a thinner inferior LET might representa marker of DED severity and emphasized the role of LESCsin ocular surface diseases

The bulbar conjunctiva is an essential tissue of theocular surface with numerous ocular surface cell populationsincluding inflammatory cells and goblet cells [28 29] Inthis study the mean BET in dry eye patients was signifi-cantly increased as compared to normal eyes Moreover thethickness of the conjunctival epithelium layers was directly


correlated to symptoms (OSDI) and tear film alterations(TBUT) The infiltration of inflammatory cells and tissueedema observed within the conjunctiva in DED patientsmight explain at least in part the thickening of the conjunc-tival epithelium [30]

Although the changes in ocular surface epithelium thick-ness evaluated with SD-OCT are not specific of a particularetiology of DED and may also be observed in other ocularsurface diseases this parameter is providing useful informa-tion for the evaluation of ocular surface tissue changes Giventhat it is already used for the evaluation of keratoconus ocularsurface epithelial mapping especially corneal limbus epithe-lial mapping might be used in association with other clinicalparameters to monitor DED ocular surface changes andthe benefit of different treatments in the future

Conflict of Interests

No conflicting relationship exists for any author

Acknowledgment

This study is supported by the Central Health ResearchProject Fund (W2013BJ47) China

References

[1] ldquoThe definition and classification of dry eye disease report ofthe definition and classification subcommittee of the interna-tional Dry Eye WorkShop (2007)rdquo Ocular Surface vol 5 no 2pp 75ndash92 2007

[2] M E Stern R W Beuerman R I Fox J Gao A K Mircheffand S C Pflugfelder ldquoThe pathology of dry eye the interactionbetween the ocular surface and lacrimal glandsrdquoCornea vol 17no 6 pp 584ndash589 1998

[3] YWei and P A Asbell ldquoThe core mechanism of dry eye diseaseis inflammationrdquo Eye and Contact Lens vol 40 no 4 pp 248ndash256 2014

[4] M Francoz I Karamoko C Baudouin and A Labbe ldquoOcularsurface epithelial thickness evaluation with spectral-domainoptical coherence tomographyrdquo Investigative Ophthalmology ampVisual Science vol 52 no 12 pp 9116ndash9123 2011

[5] A Labbe Q Liang Z Wang et al ldquoCorneal nerve structureand function in patients with non-sjogren dry eye clinical cor-relationsrdquo Investigative Ophthalmology and Visual Science vol54 no 8 pp 5144ndash5150 2013

[6] A Yagci and C Gurdal ldquoThe role and treatment of inflamma-tion in dry eye diseaserdquo International Ophthalmology vol 34no 6 pp 1291ndash1301 2014

[7] X Cui J Hong F Wang et al ldquoAssessment of corneal epithelialthickness in dry eye patientsrdquo Optometry amp Vision Science vol91 no 12 pp 1446ndash1454 2014

[8] D Z Reinstein T E Yap T J Archer M Gobbe and R H Sil-verman ldquoComparison of corneal epithelial thickness measure-ment between fourier-domain OCT and very high-frequencydigital ultrasoundrdquo Journal of Refractive Surgery vol 31 no 7pp 438ndash445 2015

[9] K-S Na J-W Mok J Y Kim C R Rho and C-K JooldquoCorrelations between tear cytokines chemokines and solublereceptors and clinical severity of dry eye diseaserdquo Investigative

Ophthalmology amp Visual Science vol 53 no 9 pp 5443ndash54502012

[10] A Alhatem B Cavalcanti and P Hamrah ldquoIn vivo confocalmicroscopy in dry eye disease and related conditionsrdquo Seminarsin Ophthalmology vol 27 no 5-6 pp 138ndash148 2012

[11] J A Hallak S Jassim V Khanolkar and S Jain ldquoSymptomburden of patients with dry eye disease a four domain analysisrdquoPLoS ONE vol 8 no 12 Article ID e82805 2013

[12] G Cardona C Garcıa C Seres M Vilaseca and J GispetsldquoBlink rate blink amplitude and tear film integrity duringdynamic visual display terminal tasksrdquo Current Eye Researchvol 36 no 3 pp 190ndash197 2011

[13] K S Na K Han Y G Park C Na and C K Joo ldquoDepressionstress quality of life and dry eye disease in Korean womena population-based studyrdquo Cornea vol 34 no 7 pp 733ndash7382015

[14] Y Yang J Hong S X Deng and J Xu ldquoAge-related changesin human corneal epithelial thickness measured with anteriorsegment optical coherence tomographyrdquo Investigative Ophthal-mology and Visual Science vol 55 no 8 pp 5032ndash5038 2014

[15] C Fabiani S Barabino S Rashid and M R Dana ldquoCornealepithelial proliferation and thickness in a mouse model of dryeyerdquo Experimental Eye Research vol 89 no 2 pp 166ndash171 2009

[16] W Chen Z Li J Hu et al ldquoCorneal alternations induced bytopical application of benzalkonium chloride in rabbitrdquo PLoSONE vol 6 no 10 Article ID e26103 2011

[17] A J Kanellopoulos and G Asimellis ldquoIn vivo 3-dimensionalcorneal epithelial thickness mapping as an indicator of dry eyepreliminary clinical assessmentrdquo American Journal of Ophthal-mology vol 157 no 1 pp 63e2ndash68e2 2014

[18] B Erdelyi R Kraak A Zhivov R Guthoff and J NemethldquoIn vivo confocal laser scanning microscopy of the cornea indry eyerdquoGraefersquos Archive for Clinical and Experimental Ophthal-mology vol 245 no 1 pp 39ndash44 2007

[19] E Villani D Galimberti F Viola C Mapelli and R RatiglialdquoThe cornea in Sjogrenrsquos syndrome an in vivo confocal studyrdquoInvestigative Ophthalmology and Visual Science vol 48 no 5pp 2017ndash2022 2007

[20] I S J Tuominen Y T Konttinen M H Vesaluoma J A OMoilanenM Helinto and TM T Tervo ldquoCorneal innervationand morphology in primary Sjogrenrsquos syndromerdquo InvestigativeOphthalmology andVisual Science vol 44 no 6 pp 2545ndash25492003

[21] M Dogru and K Tsubota ldquoNew insights into the diagnosis andtreatment of dry eyerdquo Ocular Surface vol 2 no 2 pp 59ndash752004

[22] L S Vera J Gueudry A Delcampe J-C Roujeau G Brasseurand M Muraine ldquoIn vivo confocal microscopic evaluation ofcorneal changes in chronic Stevens-Johnson syndrome andtoxic epidermal necrolysisrdquo Cornea vol 28 no 4 pp 401ndash4072009

[23] B Steger L Speicher W Philipp and N E Bechrakis ldquoIn vivoconfocal microscopic characterisation of the cornea in chronicgraft-versus-host disease related severe dry eye diseaserdquo BritishJournal of Ophthalmology vol 99 no 2 pp 160ndash165 2015

[24] M J Lee A Y Ko J H Ko et al ldquoMesenchymal stemstromalcells protect the ocular surface by suppressing inflammation inan experimental dry eyerdquo Molecular Therapy vol 23 no 1 pp139ndash146 2015

[25] C Baudouin ldquoA new approach for better comprehension of dis-eases of the ocular surfacerdquo Journal Francais drsquoOphtalmologievol 30 pp 239ndash246 2007


[26] A J Shortt S J Tuft and J T Daniels ldquoCorneal stem cells in theeye clinicrdquo British Medical Bulletin vol 100 no 1 pp 209ndash2252011

[27] R A Thoft L A Wiley and N Sundarraj ldquoThe multipotentialcells of the limbusrdquo Eye vol 3 no 2 pp 109ndash113 1989

[28] J T Henriksson C S De PaivaW Farley S C Pflugfelder A RBurns and J P G Bergmanson ldquoMorphologic alterations of thepalpebral conjunctival epithelium in a dry eye modelrdquo Corneavol 32 no 4 pp 483ndash490 2013

[29] P Argueso M Balaram S Spurr-Michaud H T KeutmannMR Dana and I K Gipson ldquoDecreased levels of the goblet cellmucin MUC5AC in tears of patients with Sjogren syndromerdquoInvestigative Ophthalmology amp Visual Science vol 43 no 4 pp1004ndash1011 2002

[30] P Chhadva A Alexander A L McClellan et al ldquoThe impact ofconjunctivochalasis on dry eye symptoms and signsrdquo Investiga-tive Ophthalmology amp Visual Science vol 56 no 5 pp 2867ndash2871 2015

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Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


using IOP-lowering eye drops we observed a decreasedlimbal-conjunctival epithelial thickness and an increased bul-bar conjunctival epithelial thickness The epithelial thicknessmeasurement of ocular surface tissues with SD-OCT seemedto be an advantageous new parameter during ocular surfaceevaluation However the number of patients in each groupwas limited and correlations were not evaluated betweenepithelium thickness changes and ocular surface clinical testsThus the objective of the present study was to comparethe results of corneal limbal and conjunctival epitheliumthicknesses obtained with SD-OCT in normal subjects andnon-Sjogren dry eye patients and to evaluate the relationshipbetween these parameters and the results of ocular surfaceclinical tests

2 Patients and Methods

21 Subjects This studywas conducted at the Beijing Instituteof Ophthalmology with approval of the Medical EthicsCommittee of BeijingTongrenHospital (TREC-2013-KY012)All patients were informed of the aims of the study andtheir consent was obtained according to the declaration ofHelsinki A total of 54 patients with DED not associatedwith Sjogren syndrome (36 women and 18 men mean age4459 plusmn 1008 years range 24ndash68 years) were consecutivelyrecruited from the Cornea Unit of Beijing Tongren Hospitalfrom June 2013 to February 2014 (DED group) The samplesize was calculated according to the results of Cui et alrsquos study[7] with 80 power level DED was defined as Schirmer Itesting lt5mm andor tear film break-up time (TBUT) lt10 saccompanied by complaints of ocular irritation in the absenceof other ocular (in particular meibomian gland disease) orsystemic diseases [1] Thirty-two age- and gender-matchedcontrol subjects (20 women and 12 men mean age 4334 plusmn1081 years range 19ndash67 years) were also recruited (controlgroup) All control subjects had no complaint of ocularsurface irritation and no anterior segment abnormality onbiomicroscopic examination and ocular surface tests Exclu-sion criteria for both groups were as follows age lt18 yearssubject unable to complete the questionnaire or understandthe procedures the presence of ocular or systemic disease orthe use of topical or systemic medications that may affect thecornea and the ocular surface (except the use of nonpreservedtear substitutes in the DED group) and previous eye surgeryor contact lens wear

22 Clinical Evaluation Demographic information andmedical history were obtained from the patientsrsquo medicalrecords Each subject underwent quantification of ocular sur-face symptomswith theOcular SurfaceDisease Index (OSDI)questionnaire (range 0ndash100) Then the subjects underwentocular surface examinations in the following order tear filmbreak-up time (TBUT) corneal and conjunctival fluoresceinstaining tear film lipid layer analysis Schirmer test withoutanesthesia and corneal sensationmeasured with the Cochet-Bonnet esthesiometer

TBUT was measured by instilling fluorescein into theinferior cul-de-sac and calculating the average of three con-secutive break-up times Corneal and conjunctival staining

was evaluated under a yellow filter using the Oxford scaleand after instillation of fluorescein Tear film lipid layeranalysis was performed using interferometry (DR-1 KowaTokyo Japan) and evaluated semiquantitatively from 1 to5 (grade 5 being the most severe) [5] Schirmer I test wasperformedwithout anesthesia for 5minwith the patientrsquos eyesclosed Corneal sensation was measured using the contactnylon thread Luneau 12100mmCochet-Bonnet esthesiome-ter (Luneau Prunay-Le-Gillon France) in the central corneaand in the superior inferior nasal and temporal quadrantsMean corneal sensitivity (MCS) was defined as the mean ofthe measures obtained in the five different areas

23 SD-OCT Examination and Image Analysis SD-OCT fit-ted with an anterior segment module (Optovue CorporationFremont CA USA) was used This SD-OCT has a scan rateof 26000 axial scans per second Its axial and transverseoptical resolution were 5 120583mand 15 120583m respectively An add-on lens (CAM-L mode 60ndash20mm) was used to assess theregional corneal and conjunctival architecture and epithelialthickness Because SD-OCT examination is a noncontacttechnique it was performed before ophthalmological exami-nations in order to avoid potential epithelium alterations

The specific imaging capture technique for this study hasbeen previously described [4] Briefly patients were asked tofixate on the target light source and consecutive images wereacquired with the patientrsquos forehead and chin stabilized bya headrest Corneal epithelium thickness (CET) was definedas the epithelium thickness in the 2mm central zone of thecornea limbal epithelium thickness (LET) was defined as thelimbal-conjunctival epithelium thickness in each quadrant(superior inferior temporal and nasal) bulbar conjunctivalepithelial thickness (BET) was defined as the bulbar conjunc-tival epithelial thickness located between 2 and 3mm fromthe limbus of each quadrant (Figure 1)

The cursors were placed perpendicular to the ocularsurface epithelium from a point located just beneath thetear film (first hyperreflective layer) to the basal membrane(second hyperreflective layer) For every quadrant threemeasurements were taken (if the difference between mea-surements exceeded 3 120583m the measurement was repeatedin order to confirm thickness measurement reproducibilitythe measurement needed to be confirmed in less than 5of cases) and the results were expressed as mean plusmn SDThe measurements were taken by one researcher (HL) whowas masked to patient demographic data and the resultsof ophthalmologic examinations To evaluate interobservervariability a second examiner (QL) who was masked to theresults of the first SD-OCT analyses assessed CET LET andBET from the same images of 20 randomized patients

24 Statistical Analysis Statistical analyses were performedwith SPSS for Windows version 160 (SPSS Inc Chicago ILUSA) For each patient one eye was randomly chosen forstatistical analysis The mean plusmn SD values of each epithelialthickness variable were calculated for both the DED andcontrol groups To compare ocular surface parameters andepithelial thickness measured in normal and DED eyestwo-tailed Studentrsquos 119905-tests were performed The Pearson


47120583m 44120583m 41120583m

(a)

44120583m 47120583m 44120583m

(b)

81120583m90120583m

87120583m

(c)

66120583m75120583m60120583m

(d)

43120583m44120583m46120583m

(e)

47120583m 46120583m 51120583m

(f)



3 Results







Female 36 (667) 20 (625) 0699Male 18 (333) 12 (375)







998771

lowast

lowast

Thic

knes

s (120583

m)

110

100

90

80

70

60

50

40

30

20

4796

8714

4462

CET

ControlDED

LET BET

5023

8137

5044




4 Discussion





OSDI119903 minus0048 0071119875 0659 0514

































Acknowledgment


References






































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















47120583m 44120583m 41120583m

(a)

44120583m 47120583m 44120583m

(b)

81120583m90120583m

87120583m

(c)

66120583m75120583m60120583m

(d)

43120583m44120583m46120583m

(e)

47120583m 46120583m 51120583m

(f)



3 Results







Female 36 (667) 20 (625) 0699Male 18 (333) 12 (375)







998771

lowast

lowast

Thic

knes

s (120583

m)

110

100

90

80

70

60

50

40

30

20

4796

8714

4462

CET

ControlDED

LET BET

5023

8137

5044




4 Discussion





OSDI119903 minus0048 0071119875 0659 0514

































Acknowledgment


References






































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of



















Female 36 (667) 20 (625) 0699Male 18 (333) 12 (375)







998771

lowast

lowast

Thic

knes

s (120583

m)

110

100

90

80

70

60

50

40

30

20

4796

8714

4462

CET

ControlDED

LET BET

5023

8137

5044




4 Discussion





OSDI119903 minus0048 0071119875 0659 0514

































Acknowledgment


References






































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of



















OSDI119903 minus0048 0071119875 0659 0514

































Acknowledgment


References






































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






































Acknowledgment


References






































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of



























of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















Research Article Ocular Surface Epithelial Thickness ... · biomicroscopic examination and ocular...

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Transcript of Research Article Ocular Surface Epithelial Thickness ... · biomicroscopic examination and ocular...