|Year : 2019 | Volume
| Issue : 2 | Page : 163-166
To evaluate the relationship of macular thickness and field sensitivity in glaucoma patients
Bibhuti P Sinha1, Ankita Singh2, Nilesh Mohan3, Gyan Bhaskar3
1 Additional Professor, Dept. of RIO, IGIMS, Patna, Bihar, India
2 Senior Resident, Dept. of RIO, IGIMS, Patna, Bihar, India
3 Associate Professor, Dept. of RIO, IGIMS, Patna, Bihar, India
|Date of Submission||10-Feb-2018|
|Date of Acceptance||02-Apr-2018|
|Date of Web Publication||12-Aug-2019|
Associate Professor, RIO, IGIMS, Patna
Source of Support: None, Conflict of Interest: None
Purpose: To evaluate the strength and pattern of the relationship between visual field (VF) sensitivity and macular thickness as measured by Humphrey 24-2 & 3D-OCT ( Topcon 3D OCT-1 Maestro)
Material & Method: 269 eyes of 200 consecutive patients in which 100 normal eyes, 50 Glaucoma suspect, 50 early Glaucoma and 69 eyes of Advance glaucoma were enrolled in this prospective, non-randomized and observational study. The Relationship between macular segmented layer along with visual field sensitivity in terms of mean deviation (MD) were evaluated with linear and nonlinear regression models, and the coefficient of determination (R2) was calculated. The association between Macular Thickness/VF was described by bivariate Pearson correlation coefficients.
Result: there was no significant difference between mean Inner ring and central ring OCT device in four different groups however the outer ring was the only macular parameter that could significantly differentiate between four groups. The correlation between perimetry and macular thickness shows a very weak, negative, statistically not significant correlation in normal, Glaucoma Suspect and Early Glaucoma group but as the Mean deviation (MD) increased macular thickness decreases, but this correlation is not statistically significant. However there was significant correlation between the mean deviation (MD) and Macular Thickness in the Advanced Glaucoma Group
Conclusion: Macular thickness as measured by OCT showed statistically significant correlations with glaucoma. Macular thickness measurements made with OCT have usefulness in the clinical assessment of glaucoma.
Keywords: OCT (Optical Coherence Tomography), MD (mean Deviation), Macular Thickness, Glaucoma
|How to cite this article:|
Sinha BP, Singh A, Mohan N, Bhaskar G. To evaluate the relationship of macular thickness and field sensitivity in glaucoma patients. J Indira Gandhi Inst Med Sci 2019;5:163-6
|How to cite this URL:|
Sinha BP, Singh A, Mohan N, Bhaskar G. To evaluate the relationship of macular thickness and field sensitivity in glaucoma patients. J Indira Gandhi Inst Med Sci [serial online] 2019 [cited 2023 Feb 6];5:163-6. Available from: http://www.jigims.co.in/text.asp?2019/5/2/163/301104
| Introduction :|| |
Glaucoma is characterized by progressive degeneration of retinal ganglion cells and their axons that lead to nerve Fiber layer loss, optic disc cupping, and consecutive glaucomatous visual field changes. Retinal nerve fiber layer loss is considered an early sign of glaucoma. Injury due to glaucoma is largely irreversible and hence early detection and prevention of glaucomatous damage is crucial.
The ganglion cells are arranged in layers of four to six cells in the macula; the ganglion cell layer is only one cell thick outside the macula. The ganglion cells along with the NFL constitute 30% to 35% of macular retinal thickness, although the NFL itself is a major component of total retinal thickness close to the optic nerve head.
Glaucoma is a process in which a loss of Retinal Ganglion Cells (RGCs) results in characteristic optic nerve and visual field abnormalities. Detection of glaucomatous damage is typically through observation of the Optic Nerve Head (ONH) and Retinal Nerve Fiber Layer (RNFL) and measurement of visual function with perimeter, however, both perimeter and observation of optic disc changes are subjective examinations that are prone to variability. It is for this reason that objective methods are under development to aid in the early diagnosis of glaucoma and to assist in the detection of disease progression.
| Material & Method:|| |
This study is prospective, non-randomized and observational study that has been conducted in the glaucoma clinic of Regional Institute of ophthalmology from January 2017 to January 2018. The study obtained its clearance from departmental research committee.
260 eyes of four groups Gr 1: Normal (100 eyes) Gr 2: Glaucoma Suspect (50 eyes) Gr 3: Early Glaucoma (50 eyes) Gr 4: Advance Glaucoma (69 eyes) were enrolled for study.
| Inclusion Criteria:|| |
- Age: 18 to 70yrs
- No history of retinal pathology, laser therapy, or intraocular surgery
- Patient having previous H/O Glaucoma or patient already ontreatment of Glaucoma or patient having family H/O Glaucoma.
- Patients willing to be included in study by giving informed consent
| Exclusion Criteria:|| |
- Eyes were excluded that exhibited signs of any corneal, retinal disease or when the fundus was not visible. \
- Patients with a history of neurologic diseases that could affect structural or functional measurements were excluded.
- Any other optic disc abnormality (tilted disc, optic disc drusen, optic disc pit, optic disc coloboma) that would affect the evaluation of optic disc.
- Subjects were excluded if they were unwilling or unable to participate in the study.
Normal age matched control was enrolled after obtaining informed consent. In normal group1 patients had normal ophthalmic examination, IOP, VF & OCT macula.
Glaucoma Suspect Eyes:
Patients fulfilling inclusion and exclusion criteria with IOP beyond 2 standard deviation from normal or disc suspicion were included with normal VF & OCT.
Early Glaucomatous eyes:
Patient having typical Arcuate or Para-central Scotoma and/or nasal step on their visual field test, with clusters of three or more adjacent points depressed more than 5 dB or two or more adjacent points depressed more than 10 dB. Visual field loss only on one side of the horizontal meridian and/or untreated IOP greater than 30 mmHg despite a full visual field. MD between -6 to -12dB.
Advanced glaucomatous eyes:
Patients having either a complete loss of the neuroretinal rim to the ONH margin or visual field loss above and below the horizontal meridian as determined by visual field testing as well as MD>-12dB.
In all subject’s complete ophthalmological evaluation including IOP, Gonioscopy, Visual field & OCT (Macula) was performed.
Macular Thickness at was measured using 3D-OCT(Mastero-1) and visual field Sensitivity was done using Humphrey Perimetry (24-2). Macular scans consisted of six 100-pixel radial scans centered on the fovea and spaced 30° from one to another. These scans were used to create a macular thickness map that represented either approximately the central 20° of vision (6-mm diameter map). The macular thickness map was divided into nine sections, and it was displayed as three concentric circles, including a central circle, an inner ring, and an outer ring, with each ring divided into four quadrants. The central circle, inner ring, and outer ring in the macular thickness map had diameters of 1 mm, 3 mm, and 6 mm, respectively.
This is a prospective, non randomized study consisting of 269 eyes of 200 consecutive patients in which 100 eyes were normal, 50 Glaucoma suspect , 50Early Glaucoma and 69 eyes of advance Glaucoma were enrolled to evaluate relationship between macular and NFL At Disc with visual field defect.Analysis of Macular Thickness Layer (All three rings i.e Central, Inner and Outer Ring) and comparing each ring between the four groups
| Observation and Result :|| |
The mean central in normal group was 237.83 ± 6.22, in glaucoma suspect group it was 237.48 ± 1.89, in early glaucoma group it was 237.88 ± 2.18 and in advanced glaucoma group it was 237.92 ± 2.17.
| Central Ring:|| |
The mean comparison was done using one-Way ANOVA. The F value obtained was 0.981, with a P value of > 0.05, showing that there is no statistically significant difference in the central between the four groups.
The mean inner circle in normal group was 292.33 ± 14.93, in glaucoma suspect group it was 290.14 ± 3.14, in early glaucoma group it was 290.63 ± 11.29 and in advanced glaucoma group it was 289.40 ± 4.58.
| Inner Ring:|| |
The mean comparison was done using one-Way ANOVA. The F value obtained was 0.966, with a P value of > 0.05, showing that there is no statistically significant difference in the mean inner circle between the four groups.
The mean outer circle in normal group was 289.72 ± 6.35, in glaucoma suspect group it was 288.13 ± 5.74, in early glaucoma group it was 228.13 ± 9.94 and in advanced glaucoma group it was 208.29 ± 2.16.[Table 1]
| Outer Ring:|| |
The mean comparison was done using one-Way ANOVA. The F value obtained was 2432.749, with a P value of < 0.05, showing that there is a statistically significant difference in the mean outer value between the four groups.[Figure 1]
|Table 1: Comparison of Mean of Outer Ring of Macula between the four groups|
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|Figure 1: Cone diagram showing comparison of mean outer circle between the four groups|
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| Pairwise Comparison Was Done Between All Groups in All Ring|| |
To find out the pairwise comparison, Post hoc Tukey test was applied.
Pairwise comparison of mean of central and inner ring was statistically not significant (p>0.05).
Pair Wise comparison of mean of Outer Ring of macula between the four groups [Table 2].
|Table 2: Statistically significant difference was seen in outer ring when group wise analysis was done (p value <0.05) except Normal to suspect|
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|Table 3: The correlation between perimetry and macular thickness showing a negative, statistically significant correlation in the advanced glaucoma group.|
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| Correlation Between Perimetry and Macular Thickness in All Four Groups:|| |
Pearson coefficient of correlation applied. P value < 0.05 was taken as statistically significant. The correlation between perimetry and macular thickness showing a very weak, negative, statistically not significant correlation in normal, Glaucoma Suspect and Early Glaucoma group. As the Mean deviation (MD) increased macular thickness decreases, but this correlation is not statistically significant.However there was significant correlation between the mean deviation (MD) and Macular Thickness in the Advanced Glaucoma Group.
|Figure 2: Scatterplot of macular thickness Vs Perimetry in Advance Glaucoma group|
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| Discussion:|| |
Glaucoma is one of the important causes of irreversible preventable blindness. It is important to accurately identify eyes with early structural damage and administer preventive therapy to prevent the vision loss. Recent studies with optical imaging systems have indicated that RNFL thickness may be valuable for early diagnosis of glaucoma.
According to Zeimer et al’s hypothesis, it would be logical to expect that glaucoma detection would be most readily accomplished through macular thickness assessment, because the RGC soma is 15 μmm or more in size, and its axon is only 1 to 2 μmm in size.
When first proposed, the concept that macular thickness decreased in glaucoma was viewed as heretical. It is most unusual to see macular visual field defects early in the disease, but this is because of the redundancy of the macular visual system.
In this study correlation of macular and optic disc nerve fiber layer thickness with visual field changes were analyzed. We looked at our data in a number of ways, most specifically comparing means between groups, performing regression analysis, we found following result and their supportive studies in accordance:
The results of the present study are in accordance with the studies mentioned below Viviane Guedes, Et al (January 2003) had done study to evaluate the hypothesis that macular thickness correlates with the diagnosis of glaucoma (P0.001). Inner ring, outer ring, and mean macular thickness both in prototype and commercial OCT devices were found to be significantly different between normal subjects and advanced glaucomatous eyes. The outer ring was the only macular parameter that could significantly differentiate between normal and early glaucoma with either the prototype or commercial OCT unit. In present study also the F value obtained was 2432.749, with a P value of < 0.05, showing that there is a statistically significant difference in the mean outer value between the four groups. Also, statistically significant difference was seen in outer ring when group wise analysis was done (p value <0.05) except Normal to suspect.
Felipe A. Medeiros Et al (January 2005) In his study to Evaluate the retinal nerve fiber layer, optic nerve head, and macular thickness measurements for glaucoma detection using optical coherence tomography he compared the ability of OCT retinal nerve fiber layer (RNFL), optic nerve head, and macular thickness parameters to differentiate between healthy eyes and eyes with glaucomatous visual field loss. He reported that the RNFL parameter inferior thickness had a significantly larger AUC than the macular thickness parameter with largest AUC (inferior outer macular thickness,) combination of selected RNFL and ONH parameters resulted in the best classification function for glaucoma detection when applied to the independent sample. Outer macular thickness was decreased but RNFL and ONH provides better result.
Luang CK et al (March 2005) done a study to investigate the structure-function relationship between OCT macular retinal and peripapillary nerve fiber layer (NFL) thickness and automated visual field (VF) findings 150 consecutive eyes (101 subjects) from a glaucoma service were included. Areas under the receiver operator characteristics for macular thickness were higher in areas corresponding to the VF defect location than the non corresponding locations. Areas under the receiver operator characteristics for peripapillary NFL thickness were higher than for the macular retinal thickness. They concluded that macular retinal thickness, as measured by OCT, was capable of detecting glaucomatous damage and corresponded with peripapillary NFL thickness however, peripapillary NFL thickness had higher sensitivity and specificity for the detection of VF abnormalities.
Mathers k Rosdahi JA Et al (May 2013) studied the Correlation of Macular Thickness with Visual Fields in Glaucoma Patients and Suspect to provide a quantitative comparison of the retinal thickness in the macula, with Humphrey visual field (HVF) parameters and circum papillary retinal nerve fiber layer (RNFL) defects, in glaucoma patients a Asymmetry within the same eye, between the superior macula and inferior macula, correlated with a larger PSD in that eye. There was a strong correlation between RNFL defects and retinal thinning in the macula. SD-OCT measurements of retinal thickness in the macula correlate with HVF parameters and RNFL parameters in glaucoma patients and suspects. This correlation between visual field defects and macular thickness can help in confirming the existence and extent of the visual field defect.
| Conclusion:|| |
Macular thickness was statistically significantly decreased in Early and Advance glaucoma group only in Outer Circle of the macula. In Advance glaucoma group macular thickness was strongly correlated to the visual field indices. OCT can serve as a useful guideline in diagnosis, management, prognostication and research in Glaucoma.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]