Thinning rates of retinal nerve layer and ganglion cell-inner plexiform layer in various stages of normal tension glaucoma.
AIMS
To compare the changes in the macular retinal nerve fibre layer (mRNFL), macular ganglion cell layer and inner plexiform layer (mGCIPL), and circumpapillary retinal nerve fibre layer (cpRNFL) in various stages of normal tension glaucoma (NTG) using spectral domain optical coherence tomography.


METHODS
Eyes with NTG (n=218) were assigned into three groups based on initial mean deviation (MD) as follows: mild (MD>-6 dB), moderate (-6 dB≥MD≥-12 dB) and severe (-12 dB>MD>-20 dB). Annual rates of change in mRNFL, mGCIPL and cpRNFL thickness were calculated by linear regression analysis.


RESULTS
Age, gender, spherical equivalent, and average intraocular pressure during follow-up were not significantly different among the three groups. There were significant differences in the mRNFL, mGCIPL and cpRNFL among the three groups at baseline (p<0.0001 in all sectors except for the mRNFL in the superonasal sector). The average thinning rates of the mRNFL, mGCIPL and cpRNFL were -0.38±0.32 µm/year, -0.62±0.46 µm/year and -0.86±0.83 µm/year, respectively. No significant difference in the rates of change in the mRNFL and mGCIPL were found among the groups in any sector. However, there was a significant difference in the rate of change in the cpRNFL among the groups (in all sectors: p<0.0001).


CONCLUSIONS
Changes in the mRNFL and mGCIPL can reflect the progression of NTG even in its advanced stage. However, careful interpretation of changes in the cpRNFL in the advanced stage of glaucoma is warranted due to a potential floor effect.
['Inuzuka|Hiroko|H|', 'Sawada|Akira|A|0000-0001-9173-519X', 'Inuzuka|Masayuki|M|', 'Yamamoto|Tetsuya|T|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D005260:Female D006068:Gonioscopy D006801:Humans D007429:Intraocular Pressure D057066:Low Tension Glaucoma D008297:Male D008875:Middle Aged D009412:Nerve Fibers D009798:Ocular Hypertension D012372:ROC Curve D012165:Retinal Ganglion Cells D012189:Retrospective Studies D041623:Tomography, Optical Coherence D014065:Tonometry, Ocular D058609:Visual Field Tests D014794:Visual Fields
normal tension glaucoma macular ganglion cell layer and inner plexiform layer optical coherence tomography circumpapillary retinal nerve fiber layer macular retinal nerve fiber layer