Abstract
Purpose :
In 2005, we began a screening study of normal volunteer subjects and classified their optic disc via the original method in order to select normal subjects for a glaucoma genome study. To date, there have been numerous previous reports on the glaucoma (GL) transition rate (GTR) in normal subjects. However, and to the best of our knowledge, this is the first study to investigate GTR based on the grading of the optic disc morphology in normal subjects. In this study, we re-examined our normal volunteer subjects and investigated GTR in each optic-disc morphology grade over the 10-year period since the beginning of our screening study.
Methods :
A total of 1,126 volunteers who had received the last ophthalmic examination 10±0.5 years before were requested to participate in the study. Of those, 460 volunteers (145 males, 315 females; mean age: 65.0±12.8 years) actively participated in the study and underwent several examinations including optic disc (via photograph), visual field, intraocular pressure, etc. On the basis of complete agreement in the diagnosis among 3 GL specialists classified the subjects as normal, glaucoma suspect (GS), or glaucoma (GL) via fundus images and visual fields (VF), and categorized them into 5 grades; N1: vertical cup to disc ratio (VCDR)< 0.3 with no notching (NT)/nerve-fiber-layer defect (NFLD) , no undermining (UM) /bayonetting (BY), N2: 0.3≤VCDR<0.6 without NT/NFLD/UM/BY, N3: 0.6≤ VCDR<0.7 without NT/NFLD/UM/BY, or VCDR<0.6 with UM or BY, GS: 0.7≤VCDR<0.9, or VCDR<0.7 with NT or NFLD, with normal VF, GL: 0.9 ≤VCDR or VF abnormality is compatible with optic disc appearance. If the grade differs between the fellow eyes, the lower grade was chosen. GTR in each grade were then compared by the Ryan's test.
Results :
Among 460 subjects, grade number changed 74 to 26 in N1, 212 to 169 in N2, 140 to 137 in N3, 34 to 79 in GS, 0 to 15 in GL through 10 years. The percentage of GTR was 1.4% in N1, 0.9% in N2, 3.6% in N3, and 23.5% in GS. There was significant difference between N1 and GS, N2 and GS, and N3 and GS in GTR (p<0.05, Ryan's test).
Conclusions :
Our findings revealed that the morphology of the optic nerve disc might affect the GTR over a 10-year time period, and that the normal optic nerve morphology grade might allow the prognosis of transition to glaucomatous state in ten years.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.