OPTICAL COHERENCE TOMOGRAPHY

DIAGNOSTIC ACCURACY OF OCT IN DETECTION OF GLAUCOMA BY TAKING PERIMETRY AS GOLD STANDARD

Abstract

“Glaucoma an optic neuropathy is a caused by progressive retinal ganglion cell
(RGC) loss associated with characteristic structural changes in the optic nerve and retinal nerve
fiber layer (RNFL).Glaucoma induced damage causes the retinal ganglion cells loss that can
result in functional loss and decrease in vision of patient . Measurement of intraocular pressure
by Tonometery, characteristics of the optic nerve head changes and associated visual field
loss are used for diagnosis of Glaucoma. Objectives: To determine the diagnostic accuracy of
Optical Coherence Tomography in detection of glaucoma taking perimetry as gold standard.
Study Design: Cross sectional (validation). Period: Six months from 17-02-2014 to 16-08-2014.
Material and Method: Regarding the Inclusion Criteria patients of glaucoma suspects that meet
the criteria mentioned in operational definition of either gender with age range between 35- 60
years were included while patients having refractive errors, hazy media, pupil size less than
4mm after dilation were not included in this study. Also patients with history diabetes mellitus,
refractive or retinal surgery were also excluded. All the data was entered and analyzed by using
SPSS V-16. Results: A total of 100 patients were included in this study during the study period
.Majority of the patients were between 35-45 years of age and minimum patients were 56-
60 years old. Mean age of the patients was 47.10±8.02 years. Males and females were 50
(50%). At OCT glaucoma was present in 71 patients while at perimetry glaucoma was present
in 69 patients .Sensitivity, specificity and diagnostic accuracy of OCT was 92.7%, 77.4%, 88.0%,
respectively .Positive predictive value and negative predictive value of OCT was 90.1% and
82.7%, respectively. Discussion: Regarding the pathogenesis of Glaucoma induced damage
is due to result of retinal ganglion cell (RGC) death with progressive loss of axons located in
the retinal nerve fiber layer (RNFL). Many clinical studies showed that optic nerve head (ONH)
damage and thinning of the RNFL occur earlier than the appearance of Glaucoma induced
visual field defects; Conclusion: In conclusion, glaucoma suspects undergoing the OCT can
be assessed for the presence of glaucoma based purely on the results of the OCT.