Retinal and optic nerve evaluation by optical coherence tomography in adults with obstructive sleep apnea–hypopnea syndrome (OSAHS)

Objective

To assess the peripapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) morphologic parameters, and macular thickness and volume in patients affected by obstructive sleep apnea–hypopnea syndrome (OSAHS).

Methods

This prospective, observational case-control study consisted of 96 eyes of 50 OSAHS patients (mean age of 50.9?±?12.4 years, best-corrected visual acuity ≥20/20, refractive error less than 3 spherocylindrical diopters, and intraocular pressure <21 mmHg) who were enrolled and compared with 64 eyes of 33 age-matched controls. Peripapillary RNFL thickness, ONH parameters, macular thickness and volume were measured by optical coherence tomography (OCT).

Results

OSAHS patients showed a significant reduction of the nasal quadrant RNFL thickness (74.7?±?15.8 μm) compared with those values observed in control patients (81.1?±?16.6 μm, p?=?0.047, Student's t-test). No differences in peripapillary RNFL thickness were observed when dividing the OSAHS group in accordance with disease severity. Vertical integrated rim area (VIRA) (0.67?±?0.41 mm³ in OSAHS vs 0.55?±?0.29 mm³ in controls; p?=?0.043, Student's t-test), horizontal integrated rim width (HIRW) (1.87?±?0.31 mm² in OSAHS vs 1.8?±?0.25 mm² in controls; p?=?0.039, Student's t-test) and disc area (2.74?±?0.62 mm² in OSAHS vs 2.48?±?0.42 mm² in controls; p?=?0.002, Student's t-test) showed significant differences, all of them being higher in the OSAHS group. Severe OSAHS had significant higher disc area (2.8?±?0.7 mm²) than controls (2.5?±?0.4 mm²; p?=?0.016, ANOVA test). Temporal inner macular thickness was significantly higher in mild–moderate OSAHS patients (270?±?12 μm) than in severe OSAHS patients (260?±?19 μm; p?=?0.021, ANOVA test).

Conclusions

OSAHS patients showed decreased peripapillary nasal RNFL thickness, and increased ONH area and volume parameters when they were evaluated by OCT. These findings suggest that neuronal degeneration might be present in the retina of OSAHS patients, as previously observed in some neurodegenerative disorders     

Novel use of 3T MRI in assessment of optic nerve volume in glaucoma

Purpose

To measure optic nerve (ON) volume using 3 T magnetic resonance imaging (MRI), to correlate ON volume with retinal nerve fiber layer (RNFL) thickness, and to determine the viability of MRI as an objective tool in distinguishing glaucoma severity.

Methods

In this cross-sectional study, 30 severe glaucoma patients, 30 mild glaucoma patients and 30 age-matched controls were recruited. All subjects underwent standard automated perimetry, RNFL analysis and 3 T MRI examinations. Glaucoma patients were classified according to the Hodapp–Anderson–Parish classification. Pearson’s correlation coefficient was used to correlate ON volume with RNFL, and receiver operating curve (ROC) analysis was performed to determine the sensitivity and specificity of ON volume in detecting glaucoma severity.

Results

Optic nerve volume was significantly lower in both the left and right eyes of the severe glaucoma group (168.70?±?46.28 mm³; 167.40?±?45.36 mm³) than in the mild glaucoma group (264.03?±?78.53 mm³; 264.76?±?78.88 mm³) and the control group (297.80?±?71.45 mm³; 296.56?±?71.02 mm³). Moderate correlation was observed between: RNFL thickness and ON volume (r?=?0.51, p <0.001), and in mean deviation of visual field and optic nerve volume (r?=?0.60, p?<?0.001). ON volume below 236 mm³ was 96 % sensitive and 80 % specific for the detection of severe glaucoma.

Conclusions

MRI measured optic nerve volume is a reliable method of assessing glaucomatous damage beyond the optic nerve head. A value of 236 mm³ and below can be used to define severe glaucoma.     

Evaluation of relationship between retinal nerve fiber layer thickness progression and visual field progression in patients with glaucoma

Purpose

To evaluate the capability of optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thickness, and visual field (VF) measurements in glaucoma progression detection.

Methods

The study examined 62 eyes of 37 glaucoma patients observed over a 3-year period. All eyes underwent at least four serial RNFL measurements performed by Cirrus OCT, with the first and last measurements separated by at least 3 years. VF testing was performed by using the Swedish interactive threshold algorithm (SITA) Standard 30-2 program of the Humphrey field analyzer (HFA) on the same day as the RNFL imaging. Both serial RNFL thicknesses and VF progression were assessed by the guided progression analysis (GPA) software program. RNFL thickness progression was evaluated by event analysis. Total deviation (TD) in the superior or inferior hemifield was also examined.

Results

A total of 295 OCT scans and 295 VFs were analyzed. Five eyes exhibited progression by OCT only and 8 eyes exhibited progression by VF GPA only. When the analysis was based on the combined measurement findings, progression was noted in 6 eyes. The average of the progressive hemifield TD at baseline for combined RNFL and VF progression was ?3.21 ± 1.38 dB, while it was ?2.17 ± 1.14 dB for RNFL progression and ?9.12 ± 3.75 dB for VF progression. The average of the progressive hemifield TD indicated a significant advancement of VF progression as compared to RNFL progression (P = 0.002).

Conclusions

When a mild VF defect is present, OCT RNFL thickness measurements are important in helping discern glaucoma progression.     

Morphological and electrophysiological outcome in prospective intravitreal bevacizumab treatment of macular edema secondary to central retinal vein occlusion

Purpose

To evaluate intravitreal bevacizumab (IVB) treatment in patients with central retinal vein occlusion (CRVO) by spectral domain optical coherence tomography (OCT) and electroretinography (ERG).

Methods

Twenty-two CRVO patients were treated with IVB injections and followed for 1 year. Morphological effect of treatment was observed with fluorescent angiography and OCT. Functional effect was followed with best corrected visual acuity (BCVA) and ERG: combined rod-cone response of the standard full-field ERG (dark adapted 3.0 ERG), photopic negative response (PhNR), and pattern ERG (PERG).

Results

Best corrected visual acuity (BCVA) improved by 18.2 letters after 6 months (p ≤ 0.001) and additional 4.7 letters by the 12th month (p ≤ 0.001). The central retinal thickness of 829.8 ± 256.7 μm decreased to 398.8 ± 230 μm (p ≤ 0.001) after 6 months and to 303.7 ± 128.9 μm during the following 6 months (p ≤ 0.001). The total macular volume (14.4 ± 4.2 mm³) decreased to 9.6 ± 3.2 mm³ and 8.5 ± 2.0 mm³ after 6 months and 1 year of treatment, respectively (p ≤ 0.001). Electrophysiological measures improved significantly after 6 months and 1 year of treatment: the a-wave implicit time of dark adapted 3.0 ERG from 25.6 ± 2.3 to 24.1 ± 2.1 and 24.1 ± 2.0 ms (p ≤ 0.01); the PhNR from ?5.9 ± 6.6 to ?9.4 ± 6.1 and ?10.4 ± 4.6 µV (p ≤ 0.05); the PERG P50 amplitude from 0.2 ± 0.3 to 0.9 ± 0.6 and 1.1 ± 0.6 µV (p ≤ 0.001); and N95 amplitude from 0.4 ± 0.6 to 1.2 ± 0.9 and 1.6 ± 0.9 µV (p ≤ 0.001).

Conclusions

Intravitreal bevacizumab (IVB) treatment of macular edema due to CRVO improved standard morphological measures and the electrophysiological function of outer and inner retinal layers, which was most evident in central retina.     

A comparison of false positives in retinal nerve fiber layer,optic nerve head and macular ganglion cell-inner plexiform layer from two spectral-domain optical coherence tomography devices

Background

The incidence of false positive (FP) results of optic coherence tomography (OCT) retinal nerve fiber layer (RNFL) color code in healthy subjects can be very high with Cirrus OCT. Recent evidence has shown that OCT parameters derived from macular ganglion cell-inner plexiform layer (GCIPL) have excellent ability to discriminate between normal eyes and eyes with early glaucoma.

Methods

This was a prospective, cross-sectional study. One hundred eyes from 50 healthy volunteers underwent circumpapillary scanning by Cirrus and Spectralis OCT and macular scanning using Cirrus OCT. FP rates for each of the OCT parameters, using predefined criteria for an abnormal test were calculated. Comparative analysis was performed using the McNemar test. A generalized estimating equations model (GEE) was used to compare demographic and clinical factors between the eyes with normal findings and eyes with abnormal results.

Results

The overall RNFL color-code FP rate was significantly higher for Cirrus (39 %) than for Spectralis (18 %) (P?=?0.000). The Spectralis RNFL FP rate showed no significant difference when compared to the FP rate by Cirrus GCIPL (13 %) and ONH (11 %) analysis. Axial length, mean spherical equivalent, presence of peripapillary atrophy, and tilted disc were significantly related to the RNFL FP occurrence displayed by both devices.

Conclusions

Spectralis might be more specific than Cirrus when evaluating the RNFL thickness for Caucasians and moderate myopic population. GCIPL and ONH analysis might be more useful than RNFL thickness to evaluate this population using Cirrus OCT.     

Comparison of two different spectral domain optical coherence tomography devices in the detection of localized retinal nerve fiber layer defects

Purpose

To compare the detection of localized retinal nerve fiber layer (RNFL) defects by two different spectral domain optical coherence tomography (SD-OCT) devices.

Methods

Eyes of 42 normal control subjects and 48 patients with a localized RNFL defect on red-free fundus photographs were imaged by the Cirrus (Carl Zeiss Meditec, Dublin, CA, USA) and 3D OCT (Topcon, Tokyo, Japan) devices. We compared sensitivities, specificities, and area under the receiver operating characteristic curves (AUCs) of circumpapillary RNFL (cpRNFL) thickness and ganglion cell complex (GCC) parameters between the two devices.

Results

The devices provided different cpRNFL thickness measurements. The highest sensitivities at fixed specificities of 80 % (Cirrus: 83.3 %; 3D OCT: 77.1 %) and 95 % (Cirrus: 69.8 %; 3D OCT: 68.8 %) and the largest AUCs (Cirrus: 0.90; 3D OCT: 0.88) obtained by the cpRNFL parameters of the two devices were similar. Based on the internal normative database, the deviation-from-normal map of the Cirrus OCT device and the 36-segment map of the 3D OCT device had the highest sensitivity (89.6 and 91.7 %, respectively). Among the macular GCC parameters of the 3D OCT device, inferior macular RNFL thickness had the highest sensitivity (81.2 % at a specificity of 80 %) and the largest AUC (0.89).

Conclusions

Although the two SD-OCT devices have different measurement protocols, they showed similar abilities for the detection of a localized RNFL defect.     

Development of a new strategy of visual field testing for macular dysfunction in patients with open angle glaucoma

Purpose

To explore methods of automated visual field (VF) examination for the assessment of macular function.

Method

We used a VF examination (AP-7000 automatic perimeter, Kowa, Japan) to examine macular function in 53 eyes from 29 patients with open angle glaucoma. We measured the mean total deviation (c-MD) of 16 points in the central VF located in a 2-degree-interval 4 × 4 array with various stimulus sizes (Goldmann sizes III, II, and I). The retinal nerve fiber layer (RNFL) thickness, ganglion cell complex (GCC), and ganglion cell layer plus inner plexiform layer (GCL + IPL) were measured with the 3D OCT-2000 System (Topcon, Japan). The c-MDs of various stimulus sizes were compared with the OCT parameters using the Spearman rank correlation.

Results

The average examination time was 93.5 ± 23.5 s and the c-MD values were ?11.8 ± 8.2 (stimulus size III), ?11.9 ± 9.5 (stimulus size II), and ?12.3 ± 9.6 dB (stimulus size I). The c-MD (stimulus size III) and averaged total deviations of the Humphrey Field Analysis 10-2 program were significantly correlated (ρ = 0.91). The C-MD values for stimulus size III were significantly correlated with the OCT parameters (RNFL: ρ = 0.59; GCC: ρ = 0.65; and GCL + IPL: ρ = 0.64). The correlation coefficient between the c-MD and the GCC was better for stimulus sizes II and I (ρ = 0.69) than for stimulus size III (ρ = 0.65).

Conclusion

The C-MD values for the 16 measured central VF points were significantly correlated with macular structure, and the smaller stimulus sizes of the automated VF test had a higher correlation coefficient of within 8°.     

Pattern electroretinogram in neuromyelitis optica and multiple sclerosis with or without optic neuritis and its correlation with FD-OCT and perimetry

Purpose

To evaluate the ability of transient pattern electroretinogram (PERG) parameters to differentiate between eyes of patients with neuromyelitis optica (NMO), longitudinally extensive transverse myelitis (LETM), multiple sclerosis with optic neuritis (MS + ON), multiple sclerosis without optic neuritis (MS ? ON), and controls, to compare PERG and OCT with regard to discrimination ability, and to assess the correlation between PERG, FD-OCT, and visual field measurements (VFs).

Methods

Visual field measurements and full-field stimulation PERGs based on both 48- and 14-min checks were obtained from patients with MS (n = 28), NMO (n = 20), LETM (n = 18), and controls (n = 26). In addition, FD-OCT peripapillary retinal nerve fiber layer (RNFL) and segmented macular layer measurements were obtained and their correlation coefficients were determined.

Results

Compared to controls, PERG amplitude measurements were significantly reduced in eyes with NMO and MS + ON, but not in eyes with LETM and MS ? ON. PERG amplitudes were significantly smaller in NMO and MS + ON eyes than in MS ? ON eyes. PERG and OCT performance was similar except in NMO eyes where macular thickness parameters were more efficient at detecting abnormalities. A significant correlation was found between N95 amplitude values and OCT-measured macular ganglion cell layer thickness, total retinal thickness, and temporal peripapillary RNFL thickness. PERG amplitude was also significantly associated with VF sensitivity loss. No statistically significant difference was observed with regard to the best-performing parameters of the two methods.

Conclusions

Pattern electroretinogram measurements were able to detect RNFL loss in MS + ON and NMO eyes, with a performance comparable to OCT. PERG amplitude measurements were reasonably well correlated with OCT-measured parameters.     

Long-term follow-up of OCT-guided bevacizumab treatment of macular edema due to retinal vein occlusion

Background

To evaluate the long-term outcome of an OCT-guided reinjection scheme for bevacizumab treatment of macular edema (ME) due to retinal vein occlusion.

Methods

Patients with persistent ME (>250 μm) due to central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO) received intravitreal bevacizumab 2.5 mg/0.1 ml. Visual acuity (ETDRS), ophthalmic examination and OCT were performed at baseline and at 6- to 8-week intervals. Reinjections were only performed if OCT showed persistent or recurrent ME.

Results

Sixty-one patients with a minimum follow-up of 25 weeks were included in this analysis. Mean follow-up was 60?±?29 wks. In CRVO patients, central retinal thickness (CRT) decreased from 748?±?265 µm to 372?±?224 µm (p?<?0.001) and visual acuity (VA) improved by 1.9?±?3.2 lines. In BRVO patients, mean CRT decreased from 601?±?206 µm to 386?±?178 µm (p?<?0.001) and VA improved by 1.8?±?2.6 lines. Thirty-three percent of CRVO and 15% of BRVO patients did not show a ME recurrence for ≥25 wks at last visit. Thirty-seven percent of CRVO and 50% of BRVO patients suffered recurrences of ME within the last 25 wks, whereas 30% of CRVO and 35% of BRVO patients did not achieve a complete resolution of ME at any follow-up visit after receiving a minimum of three injections. CRVO patients with dry interval of ≥25 weeks at last visit were significantly younger, had a thinner CRT at baseline and more often had a complete resolution of ME after the first injection. In CRVO and BRVO, final VA was correlated significantly with initial VA, patients’ age and final CRT. Change of VA was correlated with change of CRT in BRVO.

Conclusions

Patients with retinal vein occlusion benefit from treatment with bevacizumab. Favourable long-term results without necessity of further injections were achieved in 33% and 15% of CRVO and BRVO patients respectively. The remaining patients needed repeated injections to treat ME recurrences. However, one third of the CRVO/BRVO patients did not improve in VA, and further injections might be discontinued in these patients.     

Scanning laser ophthalmoscopic parameters of eyes with exfoliation syndrome

Purpose

To evaluate optic nerve head (ONH) characteristics in patients with exfoliation syndrome (EXS).

Methods

This was a cross-sectional, observational study in which 73 eyes from 73 patients with EXS and 93 eyes from 93 age-matched healthy subjects who met the inclusion criteria were included. Topographic measurements of the ONH and peripapillary retinal nerve fiber layer (RNFL) thickness were performed by confocal scanning laser ophthalmoscopy, using a Heidelberg retina tomograph. Outcomes of interest were studied by Student t test and χ-squared test.

Results

EXS patients and age-matched controls did not differ in ONH parameters. Nevertheless, the mean cup depth and height variation contour values were higher in the normal subjects (P = 0.07, P = 0.056, respectively). Mean RNFL thickness was 0.22 ± 0.06 mm in the EXS group and 0.26 ± 0.06 mm in the control group, (P = 0.001). Likewise, the RNFL cross-sectional area was significantly lower in exfoliative eyes (1.16 ± 0.35 mm²) than in those of the control group (1.31 ± 0.33 mm²) (P = 0.006).

Conclusions

No significant differences in ONH parameters between EXS patients and age-matched healthy subjects were observed; however, RNFL measurements in eyes with EXS showed lower values.     

Comparison of Spectralis-OCT, GDxVCC and GDxECC in assessing retinal nerve fiber layer (RNFL) in glaucomatous patients

Background

Glaucomatous optic neuropathy is characterized by a progressive loss of retinal ganglion cells (RGCs). The defects in the peripapillary retinal nerve fiber layer (RNFL) have been reported to be the earliest sign of glaucoma. We determined the agreement between RNFL thickness assessments from spectral-domain OCT (Spectarlis HRA?+?OCT; Heidelberg Engeneering, Heidelberg, Germany), scanning laser polarimetry (SLP) with variable cornea compensation (GDxVCC; Carl Zeiss Meditec, Dublin, CA, USA), and SLP with enhanced cornea compensation (GDxECC; Carl Zeiss Meditec, Dublin, CA, USA) in glaucomatous patients. Furthermore, we investigate the influence of typical scan score (TSS) on the results of GDx assessments.

Methods

The enrolled subjects were devided into different groups by modified HODAPP visual field criteria. The peripapillary RNFL thickness was assessed with the three devices . ANOVA test, Pearson and Spearman correlation coefficient, and Bland-Altman plots were used to analyse the RNFL thickness assessments.

Results

Ninety-two eyes from 92 glaucomatous subjects were analysed. These were divided into four groups: preperimetric glaucoma (n?=?26), mild glaucoma (n?=?18), moderate glaucoma (n?=?21), and severe glaucoma (n?=?27). For Spectralis-OCT, the average RNFL thickness (mean ± SD) was 99.25?±?26.31 μm, 80.52?±?16.63 μm, 71.59?±?21.15 μm, and 63.85?±?20.86 μm for preperimetric, mild, moderate, and severe glaucoma respectively. For GDxVCC, the corresponding assessments were 52.63?±?8.18 μm, 52.95?±?10.20 μm, 46.77?±?10.62 μm, and 49.70?±?13.34 μm. For GDxECC, the assessments were 49.35?±?6.52 μm, 45.92?±?7.21 μm, 42.19?±?8.00 μm, and 39.53?±?8.45 μm. All Spectralis-GDxVCC and Spectralis-GDxECC differences were statistically significant by ANOVA test. The differences between GDxVCC and GDxECC were statistically significant only for severe glaucoma. There was a highly significant correlation between Spectralis-OCT and GDxECC, as well as Spectralis-OCT and GDxVCC, in assessing the RNFL thickness. The best instrument agreement was found between GDxECC and Spectralis-OCT. The RNFL thickness assessed with Spectralis-OCT and GDxECC showed a better correlation to visual field defects than GDxVCC. Evaluating GDx assessments with typical retardation pattern GDxVCC and GDxECC showed very similar RNFL thickness results.

Conclusions

RNFL thickness assessments between GDxVCC, GDxECC, and Spectralis-OCT cannot be directly compared. The assessments are generally higher with Spectralis-OCT than with GDxVCC and GDxECC, because of differences in method of the devices. The atypical retardation pattern has a major impact on the RNFL thickness results of GDx devices. This must be taken into account when evaluating the assessed RNFL thickness results.     

Association between foveal photoreceptor status and visual acuity after resolution of diabetic macular edema by pars plana vitrectomy

Summary

We retrospectively investigated the relationship between the appearance of IS/OS line on OCT images and visual acuity after resolution of DME by vitrectomy. Postoperative visual acuity of eyes with complete IS/OS after resolution of DME was significantly better than that without complete IS/OS, though macular edema was completely resolved in both groups.

Purpose

To evaluate the correlation between photoreceptor layer status following resolution of diabetic macular edema (DME) by pars plana vitrectomy (PPV) and final visual acuity (VA).

Methods

We retrospectively studied a series of 69 eyes from 58 patients with DME who were treated with PPV. Of the 69 eyes, 37 that were examined by optical coherence tomography (OCT) for at least 6 months and that showed a final macular thickness of less than 250 µm were included in this study. We assessed the integrity of the photoreceptor inner and outer segments (IS/OS) line in the fovea, using OCT in relation to their VA and other characteristics.

Results

There were no differences in initial VA or in foveal thickness between eyes with or without complete IS/OS at final observation. However, final VA without complete IS/OS was significantly poorer (P?=?0.004). VA had improved by more than 2 lines in eight of ten eyes with complete IS/OS and in ten of 27 eyes without complete IS/OS; the groups differed significantly with regard to this percentage (P?=?0.03).

Conclusions

The postoperative photoreceptor status of the fovea is closely related to the final VA after resolution of DME by PPV.     

Evaluation of inner retinal thickness around the optic disc using optical coherence tomography of a rodent model of nonarteritic ischemic optic neuropathy

Purpose

To clarify the usefulness of optical coherence tomography (OCT) for the objective and quantitative evaluation of retinal nerve fiber layer (RNFL) thickness around the optic disc in a rodent model of nonarteritic ischemic optic neuropathy (rNAION).

Methods

Inner retinal thickness was measured using OCT before and after rNAION induction. The thicknesses of the RNFL and the inner plexiform layer (IPL) were measured using a histologic preparation before and 56 days after induction. We compared the inner retinal thickness measured by OCT with that measured by the histologic preparation.

Results

The mean inner retinal thickness around the optic disc of normal rats measured using OCT was similar to that measured using a histologic preparation (73.50 ± 4.94 vs. 75.94 ± 5.90 μm). The mean inner retinal thickness of rNAION significantly increased until the 7th day, returned to baseline on the 14th day, and decreased until the 90th day after induction. On the 56th day after rNAION induction, histologic measurements indicated that the mean RNFL thickness had decreased but that the IPL thickness was similar to that at baseline.

Conclusion

The mean inner retinal thickness measured by OCT correlated with the RNFL thickness of rNAION. OCT is useful for the objective and quantitative evaluation of RNFL thickness around the optic disc in a model of rNAION.     

Optic disc rim area to retinal nerve fiber layer thickness correlation: comparison of diabetic and normal tension glaucoma eyes

Purpose

To compare the correlation between optic disc rim area and retinal nerve fiber layer thickness (rim-RNFL correlation) in diabetic eyes with non-progressive RNFL defects and normal tension glaucoma (NTG) eyes.

Methods

Seventy-three eyes of 73 patients with preperimetric or early NTG and 25 eyes of 25 type II diabetes patients with a non-progressive RNFL defect for ≥5 years were enrolled in this retrospective cohort study. Rim areas and RNFL thicknesses were measured by Heidelberg retina tomography (HRT II) and by optical coherence tomography (Cirrus OCT), in global and 12 clock-hour parameters. Diabetic eyes were evaluated whether they were above the 95 % prediction interval (PI) for the rim-RNFL correlation of NTG.

Results

A significant linear rim-RNFL correlation was observed in NTG eyes globally and at all clock-hours, except in the 4 and 9 o’clock areas, (0.08 < r ² < 0.56, P < 0.05). Eighty-four percent of the diabetic eyes were above the 95 % PI of the rim-RNFL correlation of NTG in ≥2 clock-hours, as compared with 36 % of the eyes in the global parameter.

Conclusions

The eyes of diabetic patients with non-progressive RNFL were well-differentiated from NTG eyes by the rim-RNFL correlation.     

Measurement of retinal nerve fiber layer and macular ganglion cell–inner plexiform layer with spectral-domain optical coherence tomography in patients with optic nerve head drusen

Purpose

To evaluate the effect of optic nerve head drusen (ONHD) on the retinal nerve fiber layer (RNFL) and macular ganglion cell–inner plexiform layer (GCIPL) using Cirrus optical coherence tomography (OCT).

Methods

Fifty-seven eyes of thirty patients with ONHD and thirty-eight eyes of twenty age-matched and sex-matched control subjects underwent circumpapillary and macular scanning using Cirrus OCT. The percentages of eyes with abnormal GCIPL and RNFL values according to the Cirrus normative data were analysed and compared.

Results

Overall, eyes with ONHD showed abnormally reduced values for average and minimum GCIPL thicknesses in 35 % and 45 % of cases compared to 2 % for both values in control eyes (P?p?=?0.002). The percentage of abnormal thinning increased with higher grades of ONHD for all the parameters evaluated, so that in grade III drusen, values were abnormally reduced in 80 % of eyes in all three analyses. Regarding buried ONHD, 30 % and 4 % of eyes had an abnormally reduced minimum GCIPL and average RNFL thickness, respectively. Furthermore, 26 % of these eyes had abnormal GCIPL exams with a normal or increased RNFL thickness.

Conclusions

Both RNFL and GCIPL analysis reveal significant thinning in eyes with ONHD directly correlated with drusen severity. In buried ONHD, the abnormality rate was significantly higher with GCIPL compared to RNFL evaluation, suggesting that GCIPL analysis might be an early structural indicator of neuronal loss in the setting of thickened RNFL.     

Reproduzierbarkeit der Messung der peripapillären Nervenfaserschichtdicke

Purpose

The aim of this study was to compare the intra- and inter-examiner reproducibility of measurements obtained by optical coherence tomography (OCT) and retinal thickness analyzer (RTA).

Patients and methods

During a period of 2 months, 22 eyes of 16 patients and 6 healthy subjects were included. Two examiners (EMH, RK) successively performed three measurements of the peripapillary retinal nerve fibre layer (RNFL) thickness with RTA and OCT. The reproducibility of three individual measurements of one examiner (intra-examiner) as well as the reproducibility of the measurements between both examiners (inter-examiner) was evaluated using the Friedman test and sign test.

Results

The average thickness of the peripapillary RNFL was 154.4 µm for the first investigator (EMH) and 155.1 µm for the other investigator (RK) measured with RTA. The results obtained by OCT were 137.3 µm (EMH) and 138.9 µm (RK), respectively, generally indicating a threefold smaller range. Comparing the three measurements of one single examiner, no appreciable intra-observer dependency neither for RTA (EMH: p=0.19, RK: p=0.95) nor for OCT (EMH: p=0.51, RK: p=0.62) was observed. Inter-examiner analysis for RTA and OCT also revealed an acceptable reproducibility.

Conclusions

Measurements of peripapillary RNFL thickness using RTA and OCT exhibited intra- and inter-observer agreement.     

Comparison of cornea endothelial cell counts after combined phacovitrectomy versus pars plana vitrectomy with fragmentation

Background

To compare postoperative cornea endothelial cell loss between combined phacovitrectomy and pars plana vitrectomy (PPV) with fragmentation.

Methods

Eighty-eight consecutive patients (92 eyes) who underwent combined phacovitrectomy (53 eyes from 50 patients) or PPV with fragmentation (39 eyes from 38 patients) were enrolled in this retrospective study. Endothelial cell density (ECD) was calculated with specular microscopy at 1 and 3 months after surgery.

Results

At 3 months after surgery, the mean ECD decreased significantly from 2,646?±?296 cells/mm² to 2,422?±?347 cells/mm² in the combined phacovitrectomy group (P?<?0.001). However, the PPV with fragmentation group did not show any significant changes in ECD during the same period (from 2,123?±?628 cells/mm² to 2,073?±?574 cells/mm²). The mean endothelial cell loss in the combined phacovitrectomy group (7.9 and 9.5 %) was significantly higher than that in the PPV with fragmentation group (0.7 and 2.4 %) both at 1 and 3 months postoperatively (P?=?0.001 and P?=?0.001 respectively).

Conclusion

In this study, corneal endothelial cell loss during the early postoperative period was significantly higher after combined phacovitrectomy than after PPV with fragmentation.     

Detailed functional and structural characterization of a macular lesion in a rhesus macaque

Purpose

Animal models are powerful tools to broaden our understanding of disease mechanisms and to develop future treatment strategies. Here we present detailed structural and functional findings of a rhesus macaque suffering from a naturally occurring bilateral macular dystrophy (BMD), partial optic atrophy and corresponding reduction of central V1 signals in visual fMRI experiments when compared to data in a healthy macaque (CTRL) of similar age.

Methods

Retinal imaging included infrared and autofluorescence recordings, fluorescein and indocyanine green angiography and spectral domain optical coherence tomography (OCT) on the Spectralis HRA?+?OCT platform. Electroretinography included multifocal and Ganzfeld-ERG recordings. Animals were killed and eyes analyzed by immunohistochemistry.

Results

Angiography showed reduced macular vascularization with significantly larger foveal avascular zones (FAZ) in the affected animal (FAZ_BMD?=?8.85?mm² vs. FAZ_CTRL?=?0.32?mm²). OCT showed bilateral thinning of the macula within the FAZ (total retinal thickness, TRT_BMD?=?174?±?9???m) and partial optic nerve atrophy when compared to control (TRT_CTRL?=?303?±?45???m). Segmentation analysis revealed that inner retinal layers were primarily affected (inner retinal thickness, IRT_BMD?=?33?±?9???m vs. IRT_CTRL?=?143?±?45???m), while the outer retina essentially maintained its thickness (ORT_BMD?=?141?±?7???m vs. ORT_CTRL?=?160?±?11???m). Altered macular morphology corresponded to a preferential reduction of central signals in the multifocal electroretinography and to a specific attenuation of cone-derived responses in the Ganzfeld electroretinography, while rod function remained normal.

Conclusion

We provided detailed characterization of a primate macular disorder. This study aims to stimulate awareness and further investigation in primates with macular disorders eventually leading to the identification of a primate animal model and facilitating the preclinical development of therapeutic strategies.     

Paracentral scotoma in glaucoma detected by 10-2 but not by 24-2 perimetry

Purpose

To describe, in glaucomatous patients, spectral-domain optical coherence tomography (SD-OCT) results predictive of paracentral visual field (VF) defects present on standard automated perimetry (SAP) 10-2, but not on SAP 24-2.

Methods

The SAP 10-2 test was repeated 3 times to determine whether paracentral VF defects were present. Spectralis? HRA + OCT was used to obtain speckle-noise-reduced macular B-scans. The macular scan protocol consisted of 19 vertical cross-sectional scan lines centered on the fovea (30° × 15° volume scan), each of which was the average of 50 scans. A 3D OCT-2000 was also used to determine macular layer thicknesses and to detect abnormally thin regions (below the 1 % confidence interval of the normative data).

Results

We identified 3 cases in which paracentral VF defects were detected on SAP 10-2, but not on SAP 24-2. Paracentral VF defects were detected on all of the SAP 10-2 tests repeated 3 times, and included absolute scotoma in 2 of the 3 SAP 10-2 results. Retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) damage was diminished on SD-OCT macular images; 2 patients had RNFL and GCL thinning within and central to the parafoveal region, where the GCL is generally thickest in healthy eyes, and 1 patient had evident RNFL and GCL thinning in the papillomacular bundle.

Conclusions

Macular SD-OCT scans may be useful in deciding whether SAP 10-2 should be performed.     

Patterns of glaucoma progression in retinal nerve fiber and macular ganglion cell-inner plexiform layer in spectral-domain optical coherence tomography

Purpose

To evaluate the progressive changes of circumpapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thicknesses measured by spectral-domain optical coherence tomography (Cirrus SD-OCT) in open-angle glaucoma.

Methods

One hundred-fourteen eyes of open-angle glaucoma patients with localized RNFL defect who had 3 years’ worth of annual RNFL photography and OCT measurements were enrolled in this retrospective study. The progression rates of serial RNFL and GCIPL thicknesses (µm), angular width (°) and area (mm²) of defect on RNFL and GCIPL deviation maps were determined by linear mixed-effect models.

Results

Over a mean follow-up period of 3.16 years, 50 patients out of a total of 114 patients were classified as progressors based on the structural evaluation. The progressors showed significantly higher progression rates in average, 6 and 11 o’clock sector RNFL thicknesses, angular width and area of defect in RNFL deviation map, as well as inferotemporal and minimum GCIPL thicknesses than the non-progressors. The thicknesses of the 6 o’clock sector RNFL and minimum GCIPL exhibited the highest reduction rates among the RNFL and GCIPL parameters assessed, respectively.

Conclusions

When evaluating glaucoma progression by OCT, careful observation of the average, 6 and 11 o’clock sectors in RNFL and inferotemporal and minimum GCIPL thicknesses can be helpful. We can effectively assess early changes of glaucoma progression with GCIPL thickness as well as RNFL thickness.