Purchase this article with an account.
LUIS PABLO Pablo FORNERO, Fabian S Lerner; The Macula/RNFL ratio, a new index for assessment of glaucoma severity. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4749.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To describe a new index to assess glaucoma’s stage using Spectral Domain OCT, based on a macular thickness to retinal nerve fiber layer (RNFL) thickness ratio.
Two hundred and nine consecutive eyes (209 patients) were assessed. Eyes with myopic refraction > 6.0 diopters, retinal diseases, uveitis or non-glaucomatous optic neuropathy were excluded. Patients younger than 21 y/o were also excluded. Patients received a complete ophthalmic evaluation. Glaucoma was defined using the structural definition of the International Society for Geographical and Epidemiological Ophthalmology (ISGEO): a vertical C/D ratio of 0.7 or more, asymmetry in the cupping of the optic nerves of 0.2 or more, and/or thinning of the neuroretinal rim in any place of 0.1 or less with corresponding perimetric damage. Glaucomatous damage was classified according to disc evaluation as moderate or advanced by clinical evaluation of the optic disc. Control subjects did not have glaucoma or ocular hypertension. The protocol used for images acquisition was (ONH) and RNFL analysis, optic disc cube 200x200 and macular thickness cube 512x128, using the Cirrus OCT.(Carl Zeiss Ophthalmic Systems, Inc. Dublin). Mean values for macular segments, as well as mean Retinal Nerve Fiber Layer (RNFL) thicknesses were obtained. A ratio Macular segment/RNFL thickness was calculated for each of the 4 macular segments in the 3 groups. Statistical analysis was performed using InStat Graph pad software (La Jolla, CA).
Seventy three eyes (73) were included. Mean age of the patients was 61.4 years old. The ratio Macular segment/RNFL thickness (Mean +SD) was: 4.64, 4.96, 5.11, and 4.63 in the advanced (4.84+0.6); 3.97, 4, 4.16, and 3.91 (4+0.4) in the moderate; and 3, 3.2, 3.3 and 3.17 (3.21+ 0.2) in the control groups; respectively for temporal, superior, nasal and inferior. Advanced glaucomas had an index ranging from 4.5 to 5, moderate from 3.5 to 4.4 and controls from 3.0 to 3.5. Differences between groups were statistically significant (p<.001)
This Index was able to differentiate eyes with different stages of glaucomatous damage or controls in this population. It should be validated in other populations to assess its usefulness in the management of the disease.
This PDF is available to Subscribers Only