錢(qián) 一, 易湘龍

(新疆醫(yī)科大學(xué)第一附屬醫(yī)院眼科， 烏魯木齊 830054)

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·臨床醫(yī)學(xué)研究·

晚期青光眼患者光學(xué)相干斷層掃描檢測(cè)的視網(wǎng)膜神經(jīng)纖維層厚度與視野缺損的相關(guān)性研究

錢(qián) 一, 易湘龍

(新疆醫(yī)科大學(xué)第一附屬醫(yī)院眼科， 烏魯木齊 830054)

目的 探討基于光學(xué)相干斷層掃描( OCT)檢測(cè)晚期青光眼患者視網(wǎng)膜神經(jīng)纖維層(RNFL)厚度的應(yīng)用價(jià)值及其與患者視野缺損的相關(guān)性。方法 選擇2014年4月-2015年12月新疆醫(yī)科大學(xué)第一附屬醫(yī)院收治的青光眼患者90例(90眼)為研究對(duì)象，按照臨床分期分成早中期組40例(40眼)、晚期組50例(50眼)，采用OCT 檢測(cè)及比較兩組患者RNFL厚度與視野缺損值，并分析其相關(guān)性。結(jié)果 早中期組患者的平均眼內(nèi)壓(IOP)為(30.284±2.452)mmHg, 低于晚期組患者的平均IOP(34.453±3.568)mmHg(P<0.05)；早中期組患者的垂直杯盤(pán)比值為(0.441±0.076)，低于晚期組患者垂直杯盤(pán)比值(0.873±0.065)(P<0.05)；早中期組患者平均視網(wǎng)膜神經(jīng)纖維層厚度(RNFL) 厚度值、 上方平均 RNFL 厚度值、下方平均 RNFL 厚度值均高于晚期組患者(P<0.05)；早中期組患者全視野 MD 值、 上方半側(cè)視野MD值、下方半側(cè)視野MD值均低于晚期組患者(P<0.05)。早中期組患者平均 RNFL 厚度與全視野 MD 值、上方半側(cè)視野MD值、下方半側(cè)視野MD值均呈負(fù)相關(guān)(分別為r=-0.448,r=-0.581,r=-0.634,P均<0.05)；晚期組患者平均 RNFL 厚度與全視野 MD 值、上方半側(cè)視野 MD 值、下方半側(cè)視野 MD 值均無(wú)相關(guān)性。結(jié)論 晚期青光眼患者相對(duì)早中期患者RNFL更薄，但是視野損傷程度更嚴(yán)重；早中期患者 的RNFL 厚度和視野缺損具有負(fù)相關(guān)性， 而晚期患者的RNFL 厚度和視野缺損的相關(guān)性不是很明顯。

晚期； 青光眼患者； 光學(xué)相干斷層掃描； 視網(wǎng)膜神經(jīng)纖維層厚度； 視野缺損

青光眼屬于臨床比較常見(jiàn)的一種疑難眼病，此病發(fā)病急驟,危險(xiǎn)性比較大，容易致盲。青光眼患者在急性發(fā)作期1～2 d就可以完全失明[1]。假如患者沒(méi)有得到及時(shí)有效的治療，則視野會(huì)完全喪失而導(dǎo)致失明。由于青光眼患者在早期一般沒(méi)有自覺(jué)癥狀，導(dǎo)致難以早診斷、早發(fā)現(xiàn)，而一經(jīng)確診大部分是處于中晚期，此時(shí)已經(jīng)喪失了最佳的臨床治療時(shí)機(jī)[2]。光學(xué)相干斷層掃描(OCT) 的出現(xiàn)，為臨床定量分析青光眼患者視網(wǎng)膜神經(jīng)纖維層( RNFL) 的厚度提供了基礎(chǔ)[3-5]。早中期、晚期青光眼患者的RNFL厚度與視野缺損的關(guān)系是近年來(lái)研究的一個(gè)熱點(diǎn)。本研究旨在探討基于光學(xué)相干斷層掃描( OCT)檢測(cè)晚期青光眼患者視網(wǎng)膜神經(jīng)纖維層厚度的應(yīng)用價(jià)值及其與患者視野缺損的相關(guān)性，現(xiàn)報(bào)道如下。

1 資料與方法

1.1 一般資料 選取2014年4月-2015年12月新疆醫(yī)科大學(xué)第一附屬醫(yī)院收治的青光眼患者90例(90眼)為研究對(duì)象，其中男性54例，女性36例；年齡21～76歲，平均年齡(60.5±4.7)歲；疾病類型：慢性原發(fā)性閉角型青光眼62例(62眼)，原發(fā)性開(kāi)角型青光眼28例(28眼)。入選的病例經(jīng)視力、驗(yàn)光、眼內(nèi)壓等多項(xiàng)常規(guī)檢測(cè)，符合青光眼診斷標(biāo)準(zhǔn)，不存在眼部刺激癥狀，沒(méi)有眼部外傷史；排除干眼癥患者、具有角膜接觸鏡佩戴史者等。按照臨床視野平均缺損(MD) 分期分成早中期組40例(40眼)、晚期組50例(50眼)，兩組患者性別、 年齡等一般資料比較差異無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05)。

1.2 方法

1.2.1 視野檢查方法 運(yùn)用IVS全自動(dòng)電腦視野儀(重慶上邦醫(yī)療設(shè)備有限公司)對(duì)患者的視野進(jìn)行檢查。受試對(duì)象視野自然瞳孔，對(duì)于屈光不正及老視者則配戴近用眼鏡接受檢查。接受檢查之前讓患者進(jìn)行暗適應(yīng)約10 min。將側(cè)眼給予遮蓋，并距離固視點(diǎn)約33 cm。運(yùn)用G2程序，光標(biāo)為Ⅲ號(hào)，4 asb的背景光，視標(biāo)持續(xù)的時(shí)間約100 ms， 用感光元件CCD進(jìn)行監(jiān)測(cè)固視。所檢測(cè)的每一個(gè)視野都是檢測(cè)其中央30°范圍的59個(gè)檢測(cè)點(diǎn)(圖1)。為使研究結(jié)果更準(zhǔn)確，去除視野對(duì)比結(jié)果圖中的中央注視點(diǎn)，采用水平中線作為界點(diǎn)，將視野結(jié)果分成上半側(cè)視野與下半側(cè)視野，然后算出每半側(cè)視野之算術(shù)平均值。

圖1 環(huán)行斷層掃描

1.2.2 OCT 檢查方法 采用眼科光學(xué)相干斷層掃描儀(深圳市斯?fàn)栴D科技有限公司)檢測(cè)患者的RNFL厚度與視盤(pán)有關(guān)的形態(tài)參數(shù)，比如平均RNFL厚度、上方與下方平均RNFL厚度。RNFL厚度平均分析程序報(bào)告圖見(jiàn)圖2。OCT檢測(cè)掃描位置、RNFL成像及測(cè)量位置、掃描質(zhì)量見(jiàn)圖3。

圖2 RNFL 厚度平均分析程序報(bào)告圖

圖3 OCT檢測(cè)掃描位置、RNFL成像及測(cè)量位置、掃描質(zhì)量

2 結(jié)果

2.1 兩組平均IOP與垂直杯盤(pán)比值比較 早中期組患者的平均IOP為(30.284±2.452)mmHg,低于晚期組患者的平均IOP(34.453±3.568)mmHg (P<0.05)，見(jiàn)圖4。早中期組患者垂直杯盤(pán)比值為(0.441±0.076)，低于晚期組患者垂直的杯盤(pán)比值(0.873±0.065)(P<0.05)，見(jiàn)圖5。

圖4 兩組平均IOP比較

圖5 兩組垂直杯盤(pán)比值比較

2.2 兩組RNFL厚度及視野缺損值比較 早中期組患者平均RNFL厚度值、上方平均RNFL厚度值、下方平均RNFL厚度值均高于晚期組患者(P<0.05)；早中期組患者全視野的視野平均缺損值(MD)值、上方半側(cè)視野MD值、下方半側(cè)視野MD值均低于晚期組患者(P<0.05)，見(jiàn)表1。

表1 兩組患者RNFL厚度值與視野缺損值比較

注： 與早中期組比較，*P<0.05。

2.3 RNFL厚度和視野缺損的相關(guān)性分析 早中期組患者平均RNFL厚度與全視野MD值呈負(fù)相關(guān)(r=-0.448,P<0.05),見(jiàn)圖6；早中期組患者上方平均RNFL厚度與上方半側(cè)視野MD值呈負(fù)相關(guān)(r=-0.581,P<0.05),見(jiàn)圖7；早中期組患者下方平均RNFL厚度與下方半側(cè)視野MD值呈負(fù)相關(guān)(r=-0.634,P<0.05)，見(jiàn)圖8。晚期組患者平均RNFL厚度與全視野MD值無(wú)相關(guān)性，晚期組患者上方平均RNFL厚度與上方半側(cè)視野MD值、下方平均RNFL厚度與下方半側(cè)視野MD值無(wú)相關(guān)。

3 討論

青光眼損害一個(gè)比較明顯的特征是神經(jīng)纖維層變薄，此項(xiàng)特征的發(fā)生早于視野及視乳頭損害[6-8]。人體視網(wǎng)膜的光敏感度一旦減少5 dB時(shí)，則有一部分視網(wǎng)膜神經(jīng)節(jié)細(xì)胞會(huì)發(fā)生死亡[9-10]。所以，與視野檢測(cè)比較，檢測(cè)RNFL厚度變化能夠更早地發(fā)現(xiàn)青光眼組織的病理變化。OCT 是近年來(lái)新興起來(lái)的一種光學(xué)成像技術(shù)，具有無(wú)創(chuàng)、非侵入性、分辨率高、成像速度快、不受屈光不正等影響的特點(diǎn)[11-13]，可以定量分析RNFL 厚度變化及缺損，進(jìn)而在臨床診斷青光眼中日益受到人們的青睞。

圖6 早中期組患者平均 RNFL 厚度與全視野MD值相關(guān)性

圖7 早中期組患者上方RNFL厚度與上方半側(cè)視野MD值相關(guān)性

圖8 早中期組患者下方RNFL厚度與下方半側(cè)視野MD值相關(guān)性

本研究發(fā)現(xiàn)，早中期組患者的平均IOP低于晚期組患者的平均IOP；早中期組患者垂直杯盤(pán)比值低于晚期組患者的垂直杯盤(pán)比值，這與國(guó)外學(xué)者Kim等[14]的研究觀點(diǎn)一致。本研究對(duì)早中期及晚期青光眼患者的RNFL 厚度變化進(jìn)行了比較分析，研究結(jié)果顯示，早中期組患者平均 RNFL 厚度值、上方平均 RNFL 厚度值、下方平均 RNFL 厚度值均高于晚期組患者(P<0.05)。說(shuō)明隨著青光眼患者的病情的加重，其RNFL 厚度會(huì)逐漸變薄[15-16]。

對(duì)于青光眼患者而言，眼視功能發(fā)生變化的起初表現(xiàn)為視野改變。MD 是視野損害的一種量化指標(biāo)，可反映出視野損害的程度，一般視野損害程度越大，則MD 值越大[17-19]。本研究顯示，早中期組患者全視野MD值、上方半側(cè)視野MD值、下方半側(cè)視野MD值均低于晚期組患者(P<0.05)?？梢?jiàn)，隨著青光眼病情的加重，MD 值增大。本研究結(jié)果提示，假如不能有效控制青光眼患者的病情，視野 MD 值則會(huì)逐漸加大，患者眼壓一直處于比較高的狀態(tài)，并使得RNFL厚度會(huì)持續(xù)被損害，致使加重視野缺損，這和國(guó)外Mi等[ 20]的研究也是一致的。

Chen等[21]通過(guò)OCT檢測(cè)早期原發(fā)性開(kāi)角型青光眼患者發(fā)現(xiàn)，患者RNFL厚度和MD值呈明顯的相關(guān)性。本研究顯示，早中期組患者平均RNFL厚度與全視野MD值、上方半側(cè)視 MD值、下方半側(cè)視野MD值均呈負(fù)相關(guān)(P<0.05)，本研究觀點(diǎn)也與上述學(xué)者的觀點(diǎn)一致。說(shuō)明早中期青光眼患者隨視神經(jīng)病變程度的加重，其視野損害也逐漸變得更加嚴(yán)重。

本研究進(jìn)一步分析發(fā)現(xiàn)，晚期組患者平均 RNFL 厚度與全視野MD值無(wú)相關(guān)性，晚期組患者上方平均 RNFL 厚度與上方半側(cè)視野MD值無(wú)相關(guān)性，晚期組患者下方平均RNFL厚度與下方半側(cè)視野 MD 值無(wú)相關(guān)性。研究提示，青光眼病情進(jìn)入晚期，患者的視神經(jīng)改變與視野損害的進(jìn)展步調(diào)不一致，即便在絕對(duì)期視力功能完全喪失，視神經(jīng)結(jié)構(gòu)有可能沒(méi)有完全損害，其視力也有可能可以恢復(fù)[22-23]。

綜上所述，晚期青光眼患者相對(duì)早中期患者RNFL更薄，但是視野損傷程度更嚴(yán)重；早中期患者 的RNFL 厚度和視野缺損具有負(fù)相關(guān)性， 而晚期患者的RNFL 厚度和視野缺損的相關(guān)性不是很明顯。本研究結(jié)果可為臨床早診斷及早治療青光眼提供有價(jià)值的參考依據(jù)。

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(本文編輯 張巧蓮)

The correlation between retinal nerve fiber layer thickness and visual field defects in late primary open angle glaucoma

QIAN Yi， YI Xianglong

(DepartmentofOphthalmology,theFirstAffiliatedHospitalofXinjiangMedicalUniversity,Urumqi830054,China)

Objective To study the changes of retinal nerve fiber layer (RNFL) thickness of late primary open angle glaucoma (POAG) by optical coherence tomography (OCT), and to explore the correlation between the RNFL thickness and the visual field defect. Methods A total of 90 cases (90 eyes) with POAG in our hospital from April 2014 to 2015 December were chosen, in which 40 cases (40 eyes) with early and middle POAG went into early and middle groups and 50 cases (50 eyes) with late POAG went into late group. RNFL thickness of two groups was measured by OCT，and the visual field defect was examined by computer visual field analyzer. Results In the early and middle group, the mean intraocular pressure (IOP) was (30.284±2.452) mmHg, which was lower than that in the late group (34.453±3.568 mmHg, P<0.05). Vertical cup to disc ratio in the early and middle group was (0.441±0.076), which was lower than that in the late group (0.873±0.065, P<0.05). RNFL thickness value, above average RNFL thickness value and below average RNFL thickness value in the early and middle group were higher than the patients in the late group (P<0.05); full field MD, above the half side of the MD value and below half side of the MD value in the early and middle group were lower than that in the late group (P<0.05). RNFL thickness and full field MD value, above the half side of the MD values and beneath the half side of the MD value in the early and middle group all showed negative correlations (r=-0.448, r=-0.581, r=-0.63, and all P<0.05); the mean RNFL thickness and full field MD, above the half side of the MD values and beneath the half side of the MD value in the late group had no correlation. Conclusion OCT scanning can reflect the changes of RNFL thickness of POAG patients. For early and middle stage glaucoma patients, RNFL thickness was negative correlated with visual field defect. The correlation between RNFL thickness and visual field defect in patients with late stage was not very obvious.

Late primary open angle glaucoma; Optical coherence tomography; Retinal nerve fiber layer thickness; Visual field defect

國(guó)家自然科學(xué)基金(81260150,81560161)

錢(qián) 一(1960)，本科，副主任技師，研究方向：眼底疾病的診斷及檢查，E-mail:2362978928@qq.com。

易湘龍，男，博士，主任醫(yī)師，副教授，碩士生導(dǎo)師，研究方向：屈光不正的手術(shù)矯正，眼底病，角膜移植，E-mail: xly1010@sina.com。

R77

A

1009-5551(2016)12-1507-05

10.3969/j.issn.1009-5551.2016.12.006

2016-08-10]