Jayalatha, J (2015) A correlative study of automated perimetry and optical coherence tomography in glaucoma. Masters thesis, Madras Medical College, Chennai.
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Abstract
OBJECTIVE: To evaluate correlation between visual field parameters and retinal nerve fiber thickness, optic nerve head changes in 50 cases of glaucoma. REASON FOR THE STUDY: To evaluate correlation between structure and function of the visual field to aid in the early diagnosis of glaucoma and to prevent progression of glaucoma. The visual field function is established with octopus 301 and the structure of RNFL and ONH is done with SDOCT-SLO. MATERIAL AND METHODS: This study was carried out at glaucoma clinic, RIOGOH, Chennai, during the period 2013 – 2015. Inclusion Criteria: Primary open angle glaucoma and glaucoma suspects. Exclusion Criteria: Patient with significant media opacity, Best corrected visual acuity worse than 6/24, A spherical correction > + /-5.0D, cylinder correction >+/-2.0D, History of any retinal disease including diabetic or hypertensive retinopathy, History of any eye trauma or surgery with the exemption of any uncomplicated cataract surgery, History of any surgical or neurologic field that affect the visual field, Unreliable visual field [false positive > 33%, false negative >3 3%], Poor quality OCT images. RESULTS Statistical analysis plan - Analysis of data. To analyse the clinical profile of the patient. To document the best corrected visual acuity. Assessment of intraocular pressure and Gonioscope. Assessment of visual field by standard automated perimetry. Assessment of retinal nerve fiber thickness and optic nerve head parameters by SDOCT-SLO. SUMMARY: Structure-function maps have been previously developed in order to understand the relationship between the optic disc morphology and the corresponding visual field defects. In 2000, Garway-Heath et al reported one of the most complete structure-function maps in human eyes. Lately, Lamparter et al. described the influence of the variability of normal optic nerve head morphology. The high variability of human RNFL distribution around the opticnerve head and the intertest variability of SAP limit the possibility of obtaining stronger correlations between these tests. 1. The clinical study consists of admixture of glaucoma suspects and primary open angle glaucoma group. 100 eyes of 50 subjects were taken for the study, of which 56 eyes of 28 patients were categorized into glaucoma suspects and 44 eyes of 22 patients were categorized into primary open angle glaucoma group. 2. The mean age was 44.9+ 11.9 in the glaucoma suspects and 54.9+12.7 in the primary open angle glaucoma group. 3. The clinical study consists of 67.9% male and 32.1% female in the glaucoma suspect group and 45.5% male, 54.5% female in the primary open angle glaucoma group. 4. The range of best corrected visual acuity ranges from 6/6 to 6/24 in the glaucoma suspects and primary open angle glaucoma group. 5. The CCT corrected IOP in the right eye of glaucoma suspect group was in the range of 10-30 with the mean IOP of 18.4 and standard deviation of 4.2. The CCT corrected IOP in the left eye of glaucoma suspect group was in the range of 12-28 with the mean IOP of 18.2 and standard deviation of 3.7. The CCT corrected IOP in the right eye of primary open angle glaucoma group was in the range of 16-28 with the mean IOP of 20.6 and standard deviation of 3.7.The CCT corrected IOP in the left eye of primary open angle glaucoma group was in the range of 14-34 with the mean IOP of 20.8 and standard deviation of 5.5. 6. The range of CCT in the right eye of glaucoma suspect group was in the range of 460-607 with the mean CCT of 544.1 and standard deviation of 35.7. The range of CCT in the left eye of glaucoma suspect group was in the range of 460-608 with the mean CCT of 535.3 and standard deviation of 39.5. The range of CCT in the right eye of primary open angle group was in the range of 505-603 with the mean CCT of 541.8 and standard deviation of 22.4. The range of CCT in the left eye of primary open angle group was in the range of 505-604 with the mean CCT of 544.5 and standard deviation of 22.7. 7. The lens position is included in the clinical study since significant media opacities adversely affects the automated perimetry value and interferes with image acquisition in OCT. 8. The range of cup to disc ratio varies from 0.3-0.9 in glaucoma suspects and primary open angle glaucoma group. The mean cup to disc ratio of the right and left eye of the glaucoma suspects were 0.6 and 0.58 respectively and that of standard deviation was 0.16 and 0.17 respectively. The mean cup to disc ratio of the right and left eye of the primary open angle glaucoma group were 0.67 and 0.64 respectively and that of standard deviation of primary open angle glaucoma group was 0.15 and 0.18 respectively. 9. The range of mean sensitivity in the right and left eye of glaucoma suspect group varies between12.7-29.3 and that of primary open angle glaucoma group varies between 11.2-28.5.The mean sensitivity in the right and left eye of the glaucoma suspects was 24.2 and 24.3 respectively and that of standard deviation was 4.5 and 4.6 respectively. The mean in the right and left eye of the primary open angle group was 20.9 and 21.4 respectively and that of standard deviation was 5.1 and 4.8 respectively. The range of mean deviation in the in the right and left eye of the glaucoma suspect group was 2.1 to14.5 and -0.4 to 14.4 respectively and that of primary open angle glaucoma group was 0.1 to 16.9 and -1.3 to 16 respectively. 10. The mean defect in the right and left eye of the glaucoma suspect group was 4.21 and 3.87 respectively and that of standard deviation was 5.69 and 5.7 respectively. The mean in the right and left eye of the primary open angle glaucoma group was 5.69 and 5.7 respectively and that of standard deviation was 5.26 and 4.66 respectively. The range of loss variance in the right and left eye of the glaucoma suspect group was 1.0 to 94.5 and 0.7 to 137 respectively and that of primary open angle glaucoma group was 1.9 to 89.5 and 2.9 to 80.1 respectively. 11. The mean of loss variance in the right and left eye of the glaucoma suspect group was 22.62 and 23.01 respectively and that of standard deviation was 27.18 and 35.53 respectively. The mean of loss variance in the right and left eye of the primary open angle glaucoma group was 29.51 and 27.15 respectively and that of standard deviation was 25.9 and 24.69 respectively. 12. The reliability criteria falls under 33% in both the glaucoma suspects and the primary open angle glaucoma groups and the OCT images with signal strength of 6 and above6 with good image quality is included in this study. 13. The average retinal nerve fiber thickness in the right and left eye of the glaucoma suspect group was 102.5 and 105.4 respectively and that of standard deviation was 15.9 and 13.3 respectively which is significant. The average retinal nerve fiber thickness in the right and left eye of the primary open angle glaucoma group was 93.3 and 94.7 respectively and that of standard deviation was 17 and 17.2 respectively which is significant. 14. Pearsons correlation coefficient of RNFL average with mean sensitivity is not significant, According to Hae young L.park et al, early in the stage of preperimetric glaucoma, RNFL thickness decreases without apparent decrease in retinal sensitivity by VF which explains the nonsignificant pearsons correlation coefficient, otherwise the pearsons correlation coefficient of RNFL average in mean sensitivity and loss variance is significant which explains the strong strucrure function correlation. 15. The pearsons correlation coefficient of RNFL average in the right and left eye with the cup –disc area was -0.3644 and -0.3298 which explains significant correlation of RNFL thinning associated with increased cup disc area. CONCLUSION: In conclusion, the pearson’s correlation coefficient ‘r’ value in this study suggests a strong correlation of the functional measurements of standard automated perimetry with the structural elements of SDOCT-SLO in glaucoma suspects and in the primary open angle glaucoma group. It is also found out in this study that the best parameter to compare the structure-function relationship in glaucoma is to compare the average retinal nerve fiber layer thickness with the mean defect and the loss variance. It is also found that combining the structure-function data could potentially enhance the performance of early detection of glaucoma. The OCT also aids in the early detection of structural loss before the evidence loss of visual field function in the standard automated perimetry.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | automated perimetry ; optical coherence tomography ; glaucoma ; correlative study. |
| Subjects: | MEDICAL > Ophthalmology |
| Depositing User: | Devi S |
| Date Deposited: | 06 Oct 2018 15:16 |
| Last Modified: | 06 Oct 2018 15:16 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/9686 |
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