Abstract
Objective: The prevalence of glaucoma in those over 40 years of age in Japan is 5.0%. Of this, 78% is primary open-angle glaucoma in the broad sense and 92% is normal tension glaucoma (NTG). We examined the usefulness of frequency doubling technology (FDT) perimetry in detecting NTG.
Subjects and Methods: Among 4,014 people who underwent FDT between May 17 2010 and January 31 2011, 235 (5.9%) were FDT positive and among them, 108 were examined in ophthalmology. The diagnosis results were analyzed.
Results: Fifty-six subjects had NTG, 5 primary open-angle glaucoma, 1 primary angle-closure glaucoma and 1 secondary glaucoma. Through detailed examination of FDT negative subjects by funduscopy and tonometry, including 5 subjects who had been diagnosed with NTG and primary open-angle glaucoma, 68 subjects were found to have glaucoma. Of 172 people with FDT abnormalities only, 68 underwent further examination and glaucoma was detected in 49. Of 88 with abnormalities only in funduscopy and tonometry, 48 underwent further examination and glaucoma was detected in 19. Of the total of 68 in whom glaucoma was detected, only 3 had been positive in tonometry. Thus without FDT perimetry, glaucoma would not have been detected in 49 of 68 subjects and funduscopy and tonometry only would have discovered 19 cases of glaucoma. So the introduction of FDT increased the detection rate 3.6-fold. In 2007, by means of funduscopy and tonometry alone, only 10 of 4, 313 people were found to have glaucoma, giving a detection rate of 0.23%. However, following the introduction of FDT, the detection rate rose to 1.68%, a significant increase, in a total of 4,051 persons who were examined by funduscopy, tonometry or FDT.
Conclusion: FDT perimetry is very useful for the detection of NTG in Ningen Dock.
