Comparisons of retinal nerve fiber layer thickness after indocyanine green, brilliant blue g, or triamcinolone acetonide-assisted macular hole surgery.

Purpose. To compare the postoperative changes of the retinal nerve fiber layer (RNFL) thickness in patients with macular holes (MHs) treated with vitrectomy with indocyanine green- (ICG-), brilliant blue G- (BBG-), or triamcinolone acetonide- (TA-)assisted internal limiting membrane (ILM) peeling. Methods. Sixty-one eyes of 61 consecutive patients with MHs were studied. Each eye was randomly selected to undergo either ICG- (n = 18), BBG- (n = 21), or TA-assisted (n = 22) ILM peeling. The circumferential retinal nerve fiber layer (RNFL) thickness was determined by spectral-domain optical coherence tomography (SD-OCT) before and 1, 3, 6, 9, and 12 months postoperatively. The mean overall and the sectoral thicknesses of the RNFL were obtained for each group. Results. A transient increase of the RNFL thickness was seen in the mean overall and sectoral thicknesses except for the nasal/inferior sector at 1 month after surgery for the three groups. Then, the thickness gradually decreased and returned to the baseline level in all sectors except for the nasal/inferior sector. The differences in the RNFL thickness among the groups were not significant for at least 12 months postoperatively. Conclusions. The degree of change of the RNFL thickness was not significantly related to the type of vital stain used during MH surgery.

Comparisons of cone electroretinograms after indocyanine green-, brilliant blue G-, or triamcinolone acetonide-assisted macular hole surgery.

PURPOSE: To compare the function of retinal ganglion cells (RGCs) using the photopic negative response (PhNR) in patients who had undergone indocyaine green (ICG)-assisted, brilliant blue G (BBG)-assisted, or triamcinolone acetonide (TA)-assisted internal limiting membrane (ILM) peeling during macular hole (MH) surgery. METHODS: Forty-eight eyes of 48 patients with a macular hole were randomly divided into those undergoing ICG-assisted, BBG-assisted, or TA-assisted vitrectomy (n = 16 for each group). Full-field cone ERGs were recorded before and 1, 3, 6, 9, and 12 months postoperatively. The amplitudes and implicit times of the a-waves and b-waves and the amplitudes of the oscillatory potentials (OPs) and PhNRs were measured. The mean deviations (MDs) of standard automated perimetry and the best-corrected visual acuity (BCVA) were measured. The circumferential retinal nerve fiber layer (RNFL) thickness was evaluated by SD-OCT. RESULTS: All macular holes were closed with a significant improvement of the BCVA and MD without differences among the groups. There was no significant difference between the preoperative and postoperative RNFL thickness. The implicit times of the a-waves and b-waves were significantly prolonged, and the ΣOPs amplitude was significantly decreased postoperatively in all groups. These ERG changes were not significantly different among the groups. The postoperative PhNR amplitudes were significantly lower in the ICG group than in the BBG or TA group. CONCLUSIONS: The results indicate that the PhNR may detect subclinical impairments of RGCs caused by the possible toxic effect of ICG. This finding adds to the data that BBG and TA may be safer than ICG for use during MH surgery.

Photopic negative response of focal electoretinograms in glaucomatous eyes.

PURPOSE: To determine the clinical importance of the photopic negative response (PhNR) of the focal electoretinogram (fERG) for diagnosing glaucoma. METHODS: Fifty-nine eyes of 38 patients with open-angle glaucoma (OAG), 12 glaucoma suspects, and 32 eyes of 32 normal controls were studied. The fERGs were elicited by a 15 degrees stimulus spot on the macula region, the supero-temporal, and infero-temporal regions of the macula. The mean of the visual sensitivity was measured by standard automated perimetry (SAP). The optimal cutoff amplitudes of the focal PhNR and ratios of the focal PhNR/b-wave amplitudes that discriminated glaucomatous eyes from normal eyes were obtained from the receiver operating characteristic curves. RESULTS: The amplitudes of the PhNR were significantly smaller in patients with OAG than in normal controls (P < 0.00001). A curvilinear relationship was found between the mean sensitivity (dB, on log scale) and the PhNR amplitude, and between the mean sensitivity and the PhNR/b-wave amplitude ratio. After converting the mean sensitivity from a logarithmic to a linear scale, the amplitude of the PhNR and PhNR/b-wave ratio were linearly correlated with the SAP-determined visual sensitivity in all retinal areas (r = .428-0.544, P < 0.0001). When the optimal cutoff values were used, the sensitivity and specificity of the PhNR/b-wave amplitude ratio were 98.3% and 90.1%, respectively. CONCLUSIONS: The reduction of the focal PhNR amplitude was associated with a local decrease in the retinal sensitivity in OAG. The high sensitivity and specificity suggest that the focal PhNR can be used to detect functional loss in OAG.

Correlation between photopic negative response and retinal nerve fiber layer thickness and optic disc topography in glaucomatous eyes.

PURPOSE: To investigate whether there is a significant correlation between the photopic negative response (PhNR) of the electroretinogram (ERG) and retinal nerve fiber layer thickness and optic disc topography in glaucomatous eyes. METHODS: Ninety-nine eyes of 53 patients with open-angle glaucoma (OAG) and 30 eyes of 28 normal volunteers were studied. Photopic ERGs were elicited by red stimuli (644 nm, 1600 cd/m(2)) on a blue background (470 nm, 40 cd/m(2)). The mean deviation (MD) of the visual field was obtained by static visual field analyses. The topography of the optic nerve head was determined by confocal scanning laser ophthalmoscopy. The retinal nerve fiber layer thickness (RNFLT) around the optic nerve head was measured with a scanning laser polarimeter. RESULTS: The amplitude of the PhNR and the PhNR/b-wave ratio decreased with an increase in visual field defects. The logarithmic values of the PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the MD better than the linear values. The PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the RNFLT and the rim area of the optic disc and with the cup/disc area ratio. These correlations were higher when expressed linearly than when stated logarithmically. The sensitivity and specificity were 77% and 90% for the PhNR amplitude and 70% and 87% for the PhNR/b-wave amplitude ratio when the optimal cutoff values were used. Although the a-wave amplitude correlated with the MD, the a-wave amplitudes of most of the patients fell within the normal range. The correlation between the b-wave amplitude and MD was not significant. CONCLUSIONS: The PhNR amplitudes correlate with the decrease in function and morphology of retinal neurons in eyes with OAG. The linear relationship between the PhNR and the structural parameters indicates that inner retinal function declines proportionately with neural loss in eyes with glaucoma.