ResearchArticle Visual Evoked Potentials in Primary Open ...downloads.hindawi.com/journals/jnd/2017/9540609.pdf · ResearchArticle Visual Evoked Potentials in Primary Open Angle Glaucoma

Research ArticleVisual Evoked Potentials in Primary Open Angle Glaucoma

Mukesh Kumar Jha1 Dilip Thakur2 Nirmala Limbu2 Badri Prasad Badhu3

and Bishnu Hari Paudel2

1Department of Physiology Kathmandu University School of Medical Sciences Dhulikhel Kavre Nepal2Department of Basic and Clinical Physiology BP Koirala Institute of Health Sciences Dharan Sunsari Nepal3Department of Ophthalmology BP Koirala Institute of Health Sciences Dharan Sunsari Nepal

Correspondence should be addressed to Mukesh Kumar Jha jhamukeshjnpgmailcom

Received 2 February 2017 Revised 15 June 2017 Accepted 22 June 2017 Published 20 July 2017

Academic Editor Chaur-Jong Hu

Copyright copy 2017 Mukesh Kumar Jha et al This 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

Background and Aims Visual evoked potentials (VEPs) assess the integrity of the visual pathways from the optic nerve to theoccipital cortex Optic disc cupping and visual field loss have been associated with prolongation of latency of VEP in primary openangle glaucoma (POAG)Methods Pattern reversal and flash VEP tests were done in consenting 20 primary open angle glaucomaeyes and 40 normal control eyes Results In POAG cases the refractive error [351plusmn188 versus 188plusmn111 D 119901 = 0001] cup-discratio in percent [6600 plusmn 1698 versus 2850 plusmn 580 119901 = 0001] intraocular pressure [1955 plusmn 208 versus 1165 plusmn 164 mmHg119901 = 0001] and automated visual field pattern standard deviation [413 plusmn 696 versus 164 plusmn 045 dB 119901 = 0001] were significantlymore than in control The visual acuity [041 plusmn 029 versus 100 plusmn 000 119901 = 0001] foveal visual sensitivity [2592 plusmn 688 versus3348 plusmn 175 dB 119901 = 0001] and automated visual field mean deviation [minus963 plusmn 1058 versus 007 plusmn 154 dB 119901 = 0001] weresignificantly less in cases than in control Among VEP variables pattern reversal latency N145 [14900plusmn1575 versus 13752plusmn1520ms 119901 = 0011] flash amplitude N75 [218 plusmn 57 versus 147 plusmn 38 120583V 119901 = 0001] and flash amplitude N145 [199 plusmn 39 versus 143 plusmn38 120583V 119901 = 0001] were increased in cases The pattern reversal amplitude N75 [197 plusmn 35 versus 247 plusmn 58 120583V 119901 = 0001]amplitude P100 [309 plusmn 46 versus 607 plusmn 144 120583V 119901 = 0001] and amplitude N145 [221 plusmn 58 versus 445 plusmn 199 120583V 119901 = 0001]were decreased in cases Conclusions POAG caused glaucomatous damage to optic pathway

1 Introduction

The visual evoked potential (VEP) is the potential recordedfrom the occipital region in response to visual stimuli witha long latency response It is the evoked response that isvisible without averaging [1] Its stimulus may be one of threetypes flash full-field pattern reversal and half-field patternreversal Flash VEP is used in uncooperative patients andits latencies are more variable than the pattern reversal typeTherefore it only tests continuity of the visual pathwaysThe full-field pattern reversal is used as a usual stimulus forVEP as each eye is examined individually and especially theanterior visual pathways are evaluated well Half-field patternreversal that is used for localization of lesions behind the opticchiasm has reduced clinical application in modern imagingprocedures [1]

Primary open angle glaucoma is generally a bilateral butnot always symmetrical disease characterized by adult onsetan IOPmore than 21mmHgat somepoint in the course of thedisease an open angle of normal appearance glaucomatousoptic nerve head damage and visual field loss [2 3] It isa widely prevalent eye disease characterized by an opticneuropathy and often associated with elevated intraocularpressure leading to characteristic visual field defects andoptic nerve head damage It is well established that damageto the ganglion cells andor their axons produces these visualfield defects What is less clear is the extent to which theganglion cells undergo a rapid apoptotic death as opposedto lingering in an abnormal state If the latter holds then itraises the possibility of neuroprotection of unhealthy retinalganglion cells A possible indicator of the health of the retinalganglion cells is the latency of their response [4]

HindawiJournal of Neurodegenerative DiseasesVolume 2017 Article ID 9540609 4 pageshttpsdoiorg10115520179540609

2 Journal of Neurodegenerative Diseases

TheVEP is very useful in detecting an anterior visual con-duction disturbance however it is not specific with regard toetiology It is very useful in evaluating visual function It isnoninvasive and has excellent temporal resolution It can beused to assess the integrity or maturational state of the visualpathway in infants and preverbal children [5] For recordingVEP a stimulus is presented to the subject for a selectednumber of times and the cerebral responses are amplifiedand averaged by a computer and displayed on an oscilloscopescreen or printed out on paper It is generally elicited by themonocular stimulation of each eye while the other is covered[5]

VEP stimulation has been used in diagnosis of glaucomaIt is used for the assessment of optic nerve diseases [6]VEP latency can be used as a measure of early glaucomatousdamage before retinal ganglion cell death occurs [4] Henceit is used as a marker of reversible ganglion cell damage intrials of neuroprotective agents for the treatment of glaucomaVisual evoked potentials (VEPs) assess the integrity of thevisual pathways from the optic nerve to the occipital cortexOptic disc cupping and visual field loss have been associatedwith prolongation of VEP latency Therefore it is worthconducting a study to find the effect of glaucomatous damageon VEP latencies and amplitudes

2 Objective

Theobjective of this paper is to study visual evoked potentials(VEPs) in primary open angle glaucoma

3 Materials and Methods

This case-control study was conducted in 20 eyes diag-nosed as primary open angle glaucoma (POAG) in patientsaged 45 to 74 years and 40 control aged 38 to 72 yearsin the Electrodiagnosis Lab II (Neurophysiology Lab) ofDepartment of Physiology BPKIHSThe patients in BPKIHSOphthalmology OPD meeting the inclusion criteria andcontrols (staffs and patient attendant) were enrolled in ourstudy after the necessary ophthalmic assessment so as toexclude the other types of glaucoma and eye disorders Thecontrol to case ratio was 2 1 that is 40 control (119899 = 40119898 = 24 119891 = 16) and 20 (119899 = 20 119898 = 12 and 119891 = 8)POAG eyes All the patients were on 120573-blocker (timolol) forintraocular pressure control

31 Prerecording Procedure Experimental setup was checkedwith the room temperature maintained at the thermoneutralzone (25 plusmn 2∘C) Informed written consent was taken fromeach subject and they were familiarized with the laboratoryconditions The recording room was kept dark Anthropo-metric variables such as age (yrs) weight (kg) height (cm)and BMI (kgm2) of the subjects were recorded Ophthalmicvariables such as visual acuity refractive error foveal visualsensitivity cup-disc ratio in percent intraocular pressureautomated visual field mean deviation and automated visualfield pattern standard deviation were recorded by using VFA(Humphrey Visual Field Analyzer II 745ndash5935-4141)

32 Recording Procedure and Variables Recorded The elec-trodes were placed using Elefix gel after proper cleaningAccording to the 10ndash20 international system left occipital(LO) and right occipital (RO) electrodes were placed 5 cm leftand 5 cm right respectively from midline occipital regionMidline-frontal (MF) electrode was placed 12 cm above thenasion and two earthing electrodes were placed one onvertex (119862

119911) and another on the left hand Active electrode

was placed on the scalp over the visual cortex at Oz with thereference electrode at Fz and ground electrode positioned atforehead vertex (Cz)

321 For Pattern Reversal VEP (PR-VEP) The subjects wereasked to sit on a chair at a distance of 100 cm from the televi-sion (ONIDA 1410158401015840 color) monitorThemonitor displayed pat-tern reversal checkerboardwith check size of 1 degree (60minof arc) and a small square point in the boardrsquos center wasused for monocular fixation (covering one eye with a handwithout pressing it) of eye at the central fixation point Thiswas connected to the Nihon Kohden machine (NM-420SH636 Japan) used for recording VEP The reversal patternrate was set at a frequency of one per sec with 300ms ofanalysis time Averaging was done for 200 times to minimizethe signal-to-noise ratio The PR-VEP recording was donetwice to check the repeatability of the VEP waves produced

322 For Flash VEP The subjects were made to lie down ina supine position with their eyes closed They were asked towear a led visual stimulator (SLS-3500) which was connectedto the machine Strobe light from the stimulator was used formonocular stimulation and the flashVEP recordingwas donetwice

In both pattern reversal and flash VEP peak latencies ofN75 P100 and N145 and amplitudes of N75 P100 and N145were recorded VEP latencies were measured from the originof recording and amplitudes were measured by drawing abaseline and measuring from baseline to peak

33 Statistical Analysis Data collected were first entered inthe Microsoft Excel Worksheet (MS Office 2007 version)Mean and standard deviation were calculated Dependingon their distribution MannndashWhitney U test was used forcomparing variables between cases and controls

4 Results

41 Anthropometric Variables Among the ophthalmic vari-ables age was significantly less in control group whereasweight and body mass index were less and height was morein control but they were not significant The reason for thedifference in age may be correlated with onset of glaucoma inold aged person (see Table 1)

42 Ophthalmic Variables Among the ophthalmic variablesrefractive error cup-disc ratio in percent intraocular pres-sure and automated visual field pattern standard deviationwere significantly more in cases whereas visual acuity fovealvisual sensitivity and automated visual field mean deviationwere less in cases than in control (see Table 2)

Journal of Neurodegenerative Diseases 3

Table 1 Anthropometric variables of the cases and control

VariablesGroups

119901 valueCases (119899 = 10)(mean plusmn SD)

Control (119899 = 20)(mean plusmn SD)

Age (years) 633 plusmn 902 483 plusmn 865 0001Weight (kg) 623 plusmn 887 616 plusmn 638 NSHeight (cm) 1633 plusmn 902 1639 plusmn 563 NSBody mass index(kgm2) 232 plusmn 182 228 plusmn 147 NS

Table 2 Comparison of ophthalmic variables between cases andcontrol

VariablesGroups



VA 041 plusmn 029 100 plusmn 000 0001RE (D) 351 plusmn 188 188 plusmn 111 0001FVS (dB) 2592 plusmn 688 3348 plusmn 175 0001CDRP 6600 plusmn 1698 2850 plusmn 580 0001IOP (mmHg) 1955 plusmn 208 1165 plusmn 164 0001AVFMD (dB) minus963 plusmn 1058 007 plusmn 154 0001AVFPSD (dB) 413 plusmn 696 164 plusmn 045 0001VA = visual acuity in decimal system RE = refractive error FVS = fovealvisual sensitivity CDRP = cup-disc ratio in percent IOP = intraocularpressure AVFMD = automated visual field mean deviation AVFPSD =automated visual field pattern standard deviation

43 VEP Variables Among the VEP variables pattern rever-sal latency N145 flash amplitude N75 and flash amplitudeN145 were significantly increased in the cases than in controlPattern reversal amplitude N75 pattern reversal amplitudeP100 and pattern reversal amplitude N145 were significantlydecreased in the cases than in control group (see Table 3)

5 Discussion

This study was an attempt to compare visual evoked poten-tials (VEPs) in primary open angle glaucoma (POAG)patients and controls so as to find any evidence of differencesin VEP latencies and amplitudes VEP latencies are ameasureof early glaucomatous damage before retinal ganglion celldeath Rodarte et al reported an increase in multifocal VEPlatencies in open angle glaucoma as compared to the control[7]

In our study the visual acuity of the primary open angleglaucoma (POAG) patients was 041 plusmn 029 which is contraryto Korth [8] who found it to be below 07 and Bergua et al[9] who found it to be 08 or better The cup-disc ratio of thecases was 660plusmn1698which is supported by earlier study [10]The intraocular pressure of cases in our study was 1955plusmn208supported by Korth [8] and Parisi and Massimo [10] All thecases were on pressure reducing treatment similar to studydone by Bergua et al [9] The foveal visual sensitivity of the

Table 3 VEP variables of POAG cases and control

VariablesGroups



PL75 (ms) 6853 plusmn 1234 6730 plusmn 509 NSPL100 (ms) 10321 plusmn 1082 9825 plusmn 405 NSPL145 (ms) 14900 plusmn 1575 13752 plusmn 1520 0011PA75 (120583V) 197 plusmn 035 247 plusmn 058 0001PA100 (120583V) 309 plusmn 046 607 plusmn 144 0001PA145 (120583V) 221 plusmn 058 445 plusmn 199 0001FL75 (ms) 7553 plusmn 1555 6685 plusmn 613 NSFL100 (ms) 10971 plusmn 1838 10190 plusmn 702 NSFL145 (ms) 14947 plusmn 1974 14662 plusmn 1322 NSFA75 (120583V) 218 plusmn 057 147 plusmn 038 0001FA100 (120583V) 250 plusmn 081 278 plusmn 042 NSFA145 (120583V) 199 plusmn 039 143 plusmn 038 0001PL75 = pattern reversal latency PL100 = pattern reversal latency PL145 =pattern reversal latency PA75 = pattern reversal amplitude PA100 = patternreversal amplitude PA145 = pattern reversal amplitude FL75 = flash latencyFL100 = flash latency FL145 = flash latency FA75 = flash amplitude FA100 =flash amplitude FA145 = flash amplitude

subjects measured to compare the macular degeneration wasfound significantly less in cases The refractive error of thecases was significantly more than control (119901 = 0001) whichmeant that the corrections applied to the cases were veryhigh and the cup-disc ratio of the cases were abnormally highwhich is supported by the study done by Korth [8] Bergua etal [9] and Parisi and Massimo [10]

Pattern reversal VEP latency N145 was significantly morein cases Grippo et al [11] (2006) Thienprasiddhi et al [12](2006) Shih et al [13] (1991) Bengtsson and Choong [14](2002) and Ambrosio et al [15] (2003) The pattern reversallatency N75 and P100 of cases was longer than the control butwas not significant All the pattern reversal VEP amplitudes(N75 N100 and N145) were significantly lesser in cases sim-ilar to the studies done by Grippo et al [11] (2006) Bergua etal [9] (2004) Parisi andMassimo [10] (1992)Thienprasiddhiet al [12] (2006) Shih et al [13] (1991) Bengtsson andChoong[14] (2002) and Ambrosio et al [15] (2003)

Surprisingly the flashVEP amplitude (N75 andN145)wassignificantly higher in cases The flash VEP latencies (N75P100 and N145) were longer in cases but were not significantSimilarly the flash VEP amplitude P100 was lesser in casesbut was also not significant

When pattern reversal VEP was compared with the flashVEP variables P100 andN145 latency pattern reversal latencywas significantly less However the pattern reversal N75latency was also less but was not significant The patternreversal amplitudes (N75 P100 and N145) were significantlyhigher as compared to the flash VEP This indicates thatpattern reversal VEP is more reliable than flash VEP inclinical diagnosis (Aminoff) [4]

A positive correlation was seen between pattern reversalVEP latencies N75 and P100 (119903 = 0559 119901 = 0001) N75 and


N145 (119903 = 0586 119901 = 0001) and P100 and N145 (119903 = 0536119901 = 0001) The pattern reversal VEP latency P100 showedpositive correlation with pattern reversal amplitude P100 (119903 =0464 119901 = 0003) Similarly the flash VEP latencies N75 andP100 (119903 = 0425 119901 = 0006) P100 and N145 (119903 = 0415 119901 =0008) N75 and N145 (119903 = 0364 119901 = 0021) and flash VEPamplitudes N75 and P100 (119903 = 0412 119901 = 0008) showedpositive correlation

The average age of the POAG cases was more thanthe control The control enrolled in the study had normalautomated visual field (AVF) A certain degree of peripheralvision loss in each individual with the advancement of ageis natural So exact age matched normal could not be takenAccordingly in a study by Aminoff [4] controls were onan average 10 years younger than the patient However theeffects of age were relatively smaller (13msdecade) for themonocular latency measures and very small (01msdecade)for the interocular latency measures This suggests that therelatively smaller increase in latency that was found forthe patients might be slightly smaller if age was taken intoconsideration [4] Also the report of flash VEP was notso conclusive to compare with PR-VEP These were thelimitations of the study Nevertheless this study has createda preliminary normative data for clinical reporting purposeand it can be utilized as a background for further studies inthe related field In this way this study holds a big strength

6 Conclusion

It is concluded that POAG caused deterioration in all theophthalmic variables measured with increase in latency Theamplitude is different between pattern reversal and flashmethods

61 Future Directions Further study can be done to makeflash VEP more conclusive and useful for clinical interpreta-tion Also the VEP of the subjects of different age group canbe studied to evaluate the effect of age on VEP

Disclosure

This study was presented as a poster in 37th Congressof International Union of Physiological Sciences (IUPS) inBirmingham UK held from 21 to 26 July 2013

Conflicts of Interest

The authors declare that they have no conflicts of interest

References

[1] K E Misulis and T C Head Essentials of Clinical Neurophysi-ology Butterworth Heinemann 3rd edition pp 201ndash209 2003

[2] M B Shields Textbook of Glaucoma Williams andWilkins 4thedition pp 153ndash176 1998

[3] P Ricorda-Eva and J P Whitcher Vaughan amp Asburyrsquos GeneralOphthalmology Mc Graw Hill Lange 17th edition 2007

[4] M J Aminoff Electrodiagnosis in Clinical Neurology ChurchillLivingstone 4th edition pp 421ndash449 1999

[5] C A Johnson and S J Samuels ldquoScreening for glaucomatousvisual field loss with frequency-doubling perimetryrdquo Investiga-tive Ophthalmology amp Visual Science vol 38 pp 413ndash425 1997

[6] K Momose M Kiyosawa N Nemoto H Mori M Mochizukiand J J-H Yu ldquoPRBS-determined temporal frequency charac-teristics of VEP in glaucomardquoDocumentaOphthalmologica vol108 no 1 pp 41ndash46 2004

[7] C Rodarte D C Hood E B Yang et al ldquoThe effects of glau-coma on the latency of the multifocal visual evoked potentialrdquoBritish Journal of Ophthalmology vol 90 no 9 pp 1132ndash11362006

[8] M Korth ldquoThe value of electrophysiological testing in glauco-matous diseasesrdquo Journal of Glaucoma vol 6 no 5 pp 331ndash3431997

[9] A Bergua F K Horn P Martus A M Junemann and MKorth ldquoStereoscopic visual evoked potentials in normal sub-jects and patients with open-angle glaucomasrdquo Graefersquos Archivefor Clinical and Experimental Ophthalmology vol 242 no 3 pp197ndash203 2004

[10] V Parisi and G B Massimo ldquoVisual evoked potentials afterphotostress in patients with primary open angle glaucomaand ocular hypertensionrdquo Investigative Ophthalmology ampVisualScience vol 33 no 2 pp 436ndash442 1992

[11] T M Grippo D C Hood F N Kanadani et al ldquoA comparisonbetween multifocal and conventional VEP latency changes sec-ondary to glaucomatous damagerdquo Investigative Ophthalmologyand Visual Science vol 47 no 12 pp 5331ndash5336 2006

[12] PThienprasiddhi V C Greenstein D H Chu et al ldquoDetectingearly functional damage in glaucoma suspect and ocular hyper-tensive patients with the multifocal VEP techniquerdquo Journal ofGlaucoma vol 15 no 4 pp 321ndash327 2006

[13] Y-H Shih Z-J Huang and C-E Chang ldquoColor pattern-reversal visual evoked potential in eyes with ocular hyperten-sion and primary open-angle glaucomardquo Documenta Ophthal-mologica vol 77 no 3 pp 193ndash200 1991

[14] B Bengtsson andY F Choong ldquoEvaluation ofVEPperimetry innormal subjects and glaucoma patientsrdquo Acta OphthalmologicaScandinavica vol 80 no 6 pp 620ndash626 2002

[15] G Ambrosio G Ferrara R Vitale and R De Marco ldquoVisualevoked potentials in patients with Gravesrsquo ophthalmopathycomplicated by ocular hypertension and suspect glaucoma ordysthyroid optic neuropathyrdquoDocumentaOphthalmologica vol106 no 2 pp 99ndash104 2003

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TheVEP is very useful in detecting an anterior visual con-duction disturbance however it is not specific with regard toetiology It is very useful in evaluating visual function It isnoninvasive and has excellent temporal resolution It can beused to assess the integrity or maturational state of the visualpathway in infants and preverbal children [5] For recordingVEP a stimulus is presented to the subject for a selectednumber of times and the cerebral responses are amplifiedand averaged by a computer and displayed on an oscilloscopescreen or printed out on paper It is generally elicited by themonocular stimulation of each eye while the other is covered[5]

VEP stimulation has been used in diagnosis of glaucomaIt is used for the assessment of optic nerve diseases [6]VEP latency can be used as a measure of early glaucomatousdamage before retinal ganglion cell death occurs [4] Henceit is used as a marker of reversible ganglion cell damage intrials of neuroprotective agents for the treatment of glaucomaVisual evoked potentials (VEPs) assess the integrity of thevisual pathways from the optic nerve to the occipital cortexOptic disc cupping and visual field loss have been associatedwith prolongation of VEP latency Therefore it is worthconducting a study to find the effect of glaucomatous damageon VEP latencies and amplitudes

2 Objective

Theobjective of this paper is to study visual evoked potentials(VEPs) in primary open angle glaucoma

3 Materials and Methods

This case-control study was conducted in 20 eyes diag-nosed as primary open angle glaucoma (POAG) in patientsaged 45 to 74 years and 40 control aged 38 to 72 yearsin the Electrodiagnosis Lab II (Neurophysiology Lab) ofDepartment of Physiology BPKIHSThe patients in BPKIHSOphthalmology OPD meeting the inclusion criteria andcontrols (staffs and patient attendant) were enrolled in ourstudy after the necessary ophthalmic assessment so as toexclude the other types of glaucoma and eye disorders Thecontrol to case ratio was 2 1 that is 40 control (119899 = 40119898 = 24 119891 = 16) and 20 (119899 = 20 119898 = 12 and 119891 = 8)POAG eyes All the patients were on 120573-blocker (timolol) forintraocular pressure control

31 Prerecording Procedure Experimental setup was checkedwith the room temperature maintained at the thermoneutralzone (25 plusmn 2∘C) Informed written consent was taken fromeach subject and they were familiarized with the laboratoryconditions The recording room was kept dark Anthropo-metric variables such as age (yrs) weight (kg) height (cm)and BMI (kgm2) of the subjects were recorded Ophthalmicvariables such as visual acuity refractive error foveal visualsensitivity cup-disc ratio in percent intraocular pressureautomated visual field mean deviation and automated visualfield pattern standard deviation were recorded by using VFA(Humphrey Visual Field Analyzer II 745ndash5935-4141)

32 Recording Procedure and Variables Recorded The elec-trodes were placed using Elefix gel after proper cleaningAccording to the 10ndash20 international system left occipital(LO) and right occipital (RO) electrodes were placed 5 cm leftand 5 cm right respectively from midline occipital regionMidline-frontal (MF) electrode was placed 12 cm above thenasion and two earthing electrodes were placed one onvertex (119862

119911) and another on the left hand Active electrode

was placed on the scalp over the visual cortex at Oz with thereference electrode at Fz and ground electrode positioned atforehead vertex (Cz)

321 For Pattern Reversal VEP (PR-VEP) The subjects wereasked to sit on a chair at a distance of 100 cm from the televi-sion (ONIDA 1410158401015840 color) monitorThemonitor displayed pat-tern reversal checkerboardwith check size of 1 degree (60minof arc) and a small square point in the boardrsquos center wasused for monocular fixation (covering one eye with a handwithout pressing it) of eye at the central fixation point Thiswas connected to the Nihon Kohden machine (NM-420SH636 Japan) used for recording VEP The reversal patternrate was set at a frequency of one per sec with 300ms ofanalysis time Averaging was done for 200 times to minimizethe signal-to-noise ratio The PR-VEP recording was donetwice to check the repeatability of the VEP waves produced

322 For Flash VEP The subjects were made to lie down ina supine position with their eyes closed They were asked towear a led visual stimulator (SLS-3500) which was connectedto the machine Strobe light from the stimulator was used formonocular stimulation and the flashVEP recordingwas donetwice

In both pattern reversal and flash VEP peak latencies ofN75 P100 and N145 and amplitudes of N75 P100 and N145were recorded VEP latencies were measured from the originof recording and amplitudes were measured by drawing abaseline and measuring from baseline to peak

33 Statistical Analysis Data collected were first entered inthe Microsoft Excel Worksheet (MS Office 2007 version)Mean and standard deviation were calculated Dependingon their distribution MannndashWhitney U test was used forcomparing variables between cases and controls

4 Results

41 Anthropometric Variables Among the ophthalmic vari-ables age was significantly less in control group whereasweight and body mass index were less and height was morein control but they were not significant The reason for thedifference in age may be correlated with onset of glaucoma inold aged person (see Table 1)

42 Ophthalmic Variables Among the ophthalmic variablesrefractive error cup-disc ratio in percent intraocular pres-sure and automated visual field pattern standard deviationwere significantly more in cases whereas visual acuity fovealvisual sensitivity and automated visual field mean deviationwere less in cases than in control (see Table 2)



VariablesGroups





VariablesGroups





5 Discussion




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6 Conclusion



Disclosure




References





















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VariablesGroups





5 Discussion




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6 Conclusion



Disclosure




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OncologyJournal of





PPAR Research



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ObesityJournal of



















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OncologyJournal of





PPAR Research



Journal of

ObesityJournal of





















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OncologyJournal of





PPAR Research



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Documents

ResearchArticle Visual Evoked Potentials in Primary Open ...downloads.hindawi.com/journals/jnd/2017/9540609.pdf · ResearchArticle Visual Evoked Potentials in Primary Open Angle Glaucoma