863498

Hindawi Publishing CorporationJournal of OphthalmologyVolume 2013, Article ID 863498, 5 pageshttp://dx.doi.org/10.1155/2013/863498

Clinical StudyEffect of Pterygium Surgery on Tear Osmolarity

Kemal Türkyılmaz,1 Veysi Öner,1 Mehmet Şahin Sevim,2 Ali Kurt,3

Berrak Şekeryapan,1 andMustafa Durmuş1

1 Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School, 53100 Rize, Turkey2Department of Ophthalmology, Haydarpasa Numune Research and Education Hospital, 34668 Istanbul, Turkey3Maya Eye Hospital, 38039 Kayseri, Turkey

Correspondence should be addressed to Kemal Türkyılmaz; [email protected]

Received 7 November 2012; Accepted 10 January 2013

Academic Editor: Andrew G. Lee

Copyright © 2013 Kemal Türkyılmaz et al. is is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

Purpose. To investigate changes of dry eye test results in patients who underwent pterygium surgery.Methods. Seventy-four patientswho underwent primary pterygium surgery were enrolled in this study. At the baseline, 3-, 12-, and 18-month visits, measurementsof tear osmolarity, BUT, and Schirmer test were performed. e patients were divided into 2 groups: Group 1, which consisted ofpatients in whom pterygium did not recur, and Group 2, which consisted of patients in whom pterygium recurred aer surgery.Results. e patients in Group 1 had lower tear osmolarity levels aer surgery than those at baseline (all 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). In Group2 the tear osmolarity levels did not differ from baseline aer 18 months (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). e prevalence rates of dry eye syndrome(DES) were lower than that at baseline and 18 months aer surgery in Group 1 (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). In Group 2, the incidence of DESwas lower aer 3 months than at baseline (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃) but was similar to the baseline rate aer 12 and 18 months (both 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).Conclusions. Anormal tear �lm function associated with pterygium. Pterygium excision improved tear osmolarity and tear �lmfunction. However, tear osmolarity deteriorated again with the recurrence of pterygium.

1. Introduction

Pterygium is a common disease of the ocular surface charac-terized by the invasion of �brovascular tissue from the bulbarconjunctiva onto the cornea. It can cause chronic ocularirritation, induced astigmatism, tear �lm disturbances, anddecreased vision secondary to growth over the visual axis[1]. Although the exact etiology of pterygium is unknown,exposure to ultraviolet (UV) radiation is thought to bethe major environmental risk factor [2]. Age, hereditaryfactors, sunlight, chronic in�ammation, microtrauma, anddry eye are other possible contributing factors [3–6]. emost commonly accepted treatment for pterygium is surgicalexcision. However, the rate of recurrence aer surgery is high[7]. Several studies have used tear function tests, such asthe Schirmer test or tear breakup time (BUT), to investigatethe relationship between pterygium and dry eye syndrome(DES), with con�icting results [5, 8, 9]. In addition, a very fewstudies have evaluated the effects of the excision of pterygiumon tear function [10, 11].

Various methods (i.e., the BUT, Schirmer, and mucusfern tests) are available for the investigation of DES. However,these tests are not always reliable, and none of them aloneis sufficient for diagnosis [12]. Elevated tear osmolarity hasrecently been shown to be a reliable indicator of DES, and ithas been proposed as a potential gold standard for diagnosis[12, 13]. However, to the best of our knowledge, measure-ment of tear osmolarity has not been used to investigate therelationship between surgical excision of pterygium andDES.erefore, in this study we aimed to investigate the changesin tear osmolarity, breakup time (BUT), and Schirmer testresults in patients who had undergone pterygium surgery andto evaluate how these parameters changed when pterygiumrecurred aer primary surgery.

2. Materials andMethods

Seventy-four eyes of 74 patients that underwent primarypterygium surgery were enrolled consecutively in this pro-spective study. Clinical visits were made at baseline (before

2 Journal of Ophthalmology

surgery), 1, 7, and 15 days, and 3, 12, and 18 monthsaer surgery. At the baseline, 3-, 12-, and 18-month visits,measurements of tear osmolarity and BUT and the Schirmertest were performed by the same investigator (KT) for eachpatient.e presence of �brovascular tissue with a hori�ontallength from limbus to cornea of ≥2mm (measured by slitlamp biomicroscopy) was accepted as pterygium and treatedby pterygium surgery. Extent of its invasion onto the corneawas assessed for determining severity of pterygium. Fibrovas-cular growth onto the cornea of>0.5mm recorded during thepostoperative follow-up period was accepted as recurrence ofpterygium.e patients were divided into 2 groups: Group 1,which consisted of patients in whompterygiumdid not recur,and Group 2, which consisted of patients in whom pterygiumrecurred aer surgery. All patients were informed aboutthe study procedure and gave written informed consent toparticipate. is study followed the Tenets of the Declarationof Helsinki and was approved by the Recep Tayyip ErdoganUniversity Medical Faculty Ethics Committee.

Each patient underwent a standard ophthalmologicalexamination to exclude patients with ocular or extraoculardiseases other than pterygium that could affect tear �lmfunction, such as blepharitis, ocular allergy, thyroid diseases,lacrimal systemdisorders, diabetes, collagen diseases, and useof any topical or systemic drug during the 3-month periodbefore the examination.

2.1. Surgical Procedures. Aer topical and subconjunctivaladministration of 2% lidocaine for anesthesia, the head of thepterygiumwas separated and dissected away from the cornea.e pterygiumwas resected, the episcleral and Tenon’s tissueswere dissected away from the overlying sclera, and thedissociated edges of the conjunctiva were closed with 10/0polyglycolic acid suture, leaving a 4mmarea of bare sclera. Atthe end of the surgery, 0.3% tobramycin ointmentwas appliedtopically before patching. Prednisolone acetate (1%) and 0.3%tobramycin were applied topically 4 times daily for 2 weeks.e sutures were removed 7 days aer surgery.

2.2. Tear Film Function Tests. e Schirmer test was per-formedwithout topical anesthesia.e length of the strip thatwas wet aer 5 minutes was measured and accepted as thetest result. e BUT was measured using �uorescein and aslit lamp with cobalt blue illumination. e average value of2 consecutive measurements was used for analysis. e BUTwas evaluated at least 30 minutes aer the Schirmer test.

2.3. Tear Osmolarity. Tear osmolarity was measured usingthe TearLab Osmolarity System (TearLab Corp., San Diego,CA, USA) at least 30 minutes aer the tear function tests foreach patient. When the system was ready, the patient wasrequested to look up, and a handled pen with a chip test cardthat could serve as a laboratory assay mounted on its tip wastouched to the inferior tear meniscus located above the lowereyelid. Aer the green light on the pen went out, indicatingthe conclusion of the tear-collection process, the pen wasplaced on the TearLab Reader. e code on the chip test cardwas entered into the TearLab Reader, and the results of the

T 1: e comparisons of the tear osmolarity, break-up time(BUT), and Schirmer test results within the groups during thefollow-up period (mean ± SD).

Group 1(𝑛𝑛 𝑛 𝑛𝑛)

Group 2(𝑛𝑛 𝑛 𝑛𝑛)

Tear osmolarity (mOsm/L)Baseline 304.9 ± 8.0 304.0 ± 11.83rd month 3𝑛1.8 ± 8.𝑛 3𝑛1.6 ± 11.712th month 3𝑛𝑛.𝑛 ± 8.8 3𝑛𝑛.𝑛 ± 11.𝑛18th month 3𝑛𝑛.1 ± 8.6 3𝑛6.7 ± 11.7

BUT (second)Baseline 1𝑛.𝑛 ± 3.𝑛 1𝑛.3 ± 3.73rd month 11.8 ± 3.8 1𝑛.7 ± 3.912th month 11.9 ± 3.𝑛 11.𝑛 ± 3.718th month 11.8 ± 3.𝑛 11.1 ± 3.9

Schirmer test (mm)Baseline 1𝑛.𝑛 ± 3.6 1𝑛.𝑛 ± 3.93rd month 1𝑛.𝑛 ± 3.𝑛 1𝑛.𝑛 ± 3.112th month 1𝑛.7 ± 3.9 1𝑛.𝑛 ± 3.618th month 1𝑛.9 ± 3.6 1𝑛.7 ± 3.6

Group 1 includes patients with no recurrence of pterygium aer primarypterygium surgery.Group 2 includes patients with recurrence of pterygium aer primarypterygium surgery.

measurement process were obtainedwithin amaximumof 30seconds. Values of >312mOsm/L were considered indicativeof DES [14].

2.4. Statistical Analysis. Statistical analyses were performedusing SPSS version 16.00. All variables were distributednormally and expressed as the mean ± standard deviation.Categorical variables were compared between the groupsusing the chi-square test. e Friedman test and paired 𝑡𝑡-testwere used for comparisons within each group.eMcNemartest was used to compare prevalence rates within each group.e level of statistical signi�cance was set at 𝑃𝑃 𝑃 𝑛.𝑛𝑛.

3. Results

ere were 50 patients (32 male and 28 female) in Group1 and 24 patients (15 male and 9 female) in Group 2. Allrecurrences of pterygium occurred between the 3rd and 18thpostoperative months. e mean age was 𝑛𝑛.𝑛 ± 6.8 (range,31 to 59) years in Group 1 and 𝑛𝑛.𝑛 ± 6.9 (range, 33 to 58)years in Group 2.e patients’ age and sex ratio did not differsigni�cantly between the groups.

e comparisons of tear osmolarity, BUT, and Schirmertest results between the groups during the follow-up periodare shown in Table 1. Tear osmolarity levels changed signif-icantly over the follow-up period within study Group 1 (all𝑃𝑃 𝑃 𝑛.𝑛𝑛1). e patients in Group 1 had signi�cantly lowertear osmolarity levels 3, 12, and 18 months aer surgery thanat baseline (all 𝑃𝑃 𝑃 𝑛.𝑛𝑛1). In contrast, in Group 2 the tearosmolarity levels decreased signi�cantly between baseline

Journal of Ophthalmology 3

and 3 months aer surgery (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃) but returned tobaseline levels at the 12-month follow-up visit (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃)and did not differ signi�cantly from baseline aer 18 months(𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃).

Fourteen of 50 eyes (28.0%) in Group 1 and 8 of 24 eyes(33.3%) in Group 2 exhibited DES preoperatively (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).e prevalence rates of DES were signi�cantly lower thanat baseline 3 (6.0%), 12 (6.0%), and 18 (8.0%) months aersurgery in Group 1 (𝑃𝑃𝑃 and 𝑃𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃 and 𝑃𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). InGroup 2, the incidence of DES was signi�cantly lower aer3 months (8.3%) than at baseline (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃) but was similarto the baseline rate aer 12 (29.1%) and 18 months (29.1%)(both 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).

e BUT results changed signi�cantly over the follow-upperiod within Group 1 (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). e patients had sig-ni�cantly higher BUT values 3, 12, and 18 months aersurgery than at baseline (all 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃). However, the resultsof the BUT test did not change signi�cantly within Group 2(𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃). In addition, the results of the Schirmer test didnot change signi�cantly within either group (both 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).

Preoperatively, the length of the �brovascular tissuecorrelated with the tear osmolarity and BUT (𝑟𝑟 𝑃 𝑟𝑃𝑃𝑃𝑟𝑟,𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃 and 𝑟𝑟 𝑃 𝑟𝑃𝑃𝑃𝑟𝑟, 𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃𝑃, resp.). However, thelength of the �brovascular tissue did not correlate with theresult of the Schirmer test (𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).

ere was no correlation between the length of the recur-rent �brovascular tissue and the results of the dry eye tests 18months aer surgery in the recurrent pterygium group (all𝑃𝑃 𝑃 𝑃𝑃𝑃𝑃).

4. Discussion

is study has demonstrated that tear osmolarity and BUTvalues improved signi�cantly aer primary pterygium exci-sion in Group 1. On the other hand, although tear osmolaritylevels were signi�cantly better 3 months aer surgery inGroup 2, they deteriorated and exceeded baseline levels aer12 and 18 months. In addition, the incidence of DES signi�-cantly decreased aer excision of pterygium in both groupsand increased again only in cases of recurrent pterygium.Furthermore, the BUT values of Group 2 and Schirmertest results of both groups were similar to baseline levelsthroughout the follow-up period.

Tear hyperosmolarity has been identi�ed as an importantfactor in the pathogenesis of DES and has recently beenincluded as a part of the de�nition of dry eye [15]. epreocular tear �lm layer is the eye�s �rst line of defense againstenvironmental insults such as dryness and UV exposure.erefore, some authors have thought that impairment oftear function could be a risk factor for diseases caused byUV exposure, including pterygium [8, 9]. Conversely, thereverse mechanism, that is, that conjunctival, corneal, oreyelid changes associated with pterygium disturb tear �lmfunction, has also been proposed [16].

In the present study, we found statistically signi�cantdifferences in the mean tear osmolarity values within thegroups over time. However, these changes (ranging from 300to 306mOsm/L)maynot be clinically relevant.We speculatedthat changes in the prevalence of dry eye might be more

important than the differences in the mean tear osmolarityvalues. According to the cut-off value for tear osmolarity,28% of the patients in Group 1 had DES before surgery. eprevalence of DES decreased aer surgery, and only 8% ofthe patients had DES 18 months aer pterygium removal. Incontrast, 33.3% of the patients in Group 2 had DES beforesurgery based on their tear osmolarity values.e prevalenceof DES decreased aer surgery, and only 8.3% of the patientshad DES 3 months aer surgery. However, 18 months aersurgery the prevalence of DES in Group 2 (29.1%) hadrebounded almost to the preoperative level.

In summary, the prevalence of DES according to thetear osmolarity level decreased signi�cantly aer surgicalexcision of pterygium but increased again aer recurrence ofpterygium. Accordingly, we concluded that the presence ofpterygium seems to cause DES.

Several studies have investigated the relationship betweenpterygium and changes in tear �lm function [5, 8, 9, 17, 18].Pterygium has been shown to be associated with abnormaltear �lm function, such as a shortened tear breakup time(BUT) or abnormal mucus fern patterns [8, 9, 17]. However,con�icting results have also been reported [5, 18]. In 2previous studies with follow-up periods of 1 [10] and 2 [11]months, the results of the BUT and mucus fern tests, but notthe Schirmer test, improved signi�cantly over their respectivebaseline values following pterygium excision. Conversely,another study with a 6-month follow-up period found nodifference between the Schirmer and BUT test results atbaseline and those obtained 1 and 6 months aer surgery[19].

We believe that these contradictory resultsmay have beenobtained because the methods that were used to evaluatetear function were not objective and quantitative.e presentstudy has shown that although the BUT test results improvedaer surgical treatment of pterygium with no recurrence,the Schirmer test results did not change. erefore, we canspeculate that the quantity of the tear �lm in patients withpterygium is adequate but that its quality or composition isabnormal. In addition, to the best of our knowledge, this isthe �rst time that tear osmolarity levels have been used todetermine the composition of the tear �lm in patients withpterygium, and we revealed that it improved aer surgicaltreatment and remained stable for 18 months aer surgeryso long as the pterygium did not recur.

UV-mediated genetic trauma may affect the expressionof cytokines, such as interleukin (IL)-6 and IL-8, in patientswith pterygium [20]. IL-6 and IL-8 can induce the productionof matrix metalloproteinases (MMPs), which are localizedto the advancing edges of pterygium [21, 22]. e release ofIL-6, IL-8, and MMPs into the tear �lm may lead to ocularsurface damage and tear �lm instability, ultimately resultingin epithelial cell apoptosis, goblet cell loss, a reduction inmucus secretion, and tear hyperosmolarity [15]. Eventually,a vicious cycle develops in which tear hyperosmolarity itselfstimulates MMP expression and thus leads to ocular surfacein�ammation [23].

Tear osmolarity can bemeasured by variousmethods thatrely on changes in the freezing point or electrical conductivityof the tears [24]. In some methods, prolonged ocular contact

4 Journal of Ophthalmology

during the collection of the tear sample elevates tear secretionand decreases tear osmolarity [25]. In this study, we usedthe TearLab Osmolarity System, which uses a gold electrodeinside the channel to measure the electrical impedance [24].is is a fast and simple technique that minimizes re�extear production and evaporation of the tear sample [26]. esystem is noninvasive, and the measurement takes less thana minute. Only 50 𝜇𝜇L of tear sample is collected, by passivecapillary movement, and the effect of vaporization is thusminimized.

A meta-analysis found that the recurrence rate aerpterygium surgery was higher when the bare sclera techniquewas used than when a limbal conjunctival autogra wasemployed [27].

e recurrence rate of pterygium ranges from 24% to89% when treated with the bare sclera technique [28–30] but from 1.6% to 33% when treated with conjunctivalautograing [31]. Amniotic membrane graing has beenused as an alternative to limbal conjunctival autograing,as the recurrence rate does not differ signi�cantly betweenthese techniques [27]. e recurrence rate in the presentstudy, which employed the bare sclera technique, was 32.4%.We believe that the use of limbal autograing would havedecreased the recurrence rate.

One limitation of our study is that there were gapsbetween visits, the longest of which was 9 months.erefore,we do not know for certain the earliest time at which tearosmolarity increased or pterygium recurred.

We reasonably supposed that pterygium recurrence maylead to dry eye because the pterygium disturbs tear function.Conversely, it can be speculated that dry eye may cause therecurrence of pterygium or that more severe underlying dryeye may contribute to recurrence. However, the essentiallyequal results for the tear osmolarity, BUT, and Schirmer testin our 2 groups prior to surgery provide strong evidence thatit is pterygium recurrence that leads to dry eye.

In conclusion, this study revealed that tear hyperosmo-larity and abnormal tear �lm function are associated withpterygium. Pterygium excision improved tear osmolarity andtear �lm function. However, tear osmolarity deterioratedagain with the recurrence of pterygium. erefore, we inferthat pterygium seems to cause DES and that surgical removalof pterygium alleviates pterygium-related DES.

��n��c� �f �n�eres�s

None of the authors has con�ict of interests with the paper.

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