[Optical coherence tomography analysis of the optic nerve head and macula of the fellow eye in acute unilateral nonarteritic anterior ischemic optic neuropathy]

INTRODUCTION

The objective of the study was to compare the thickness of the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) of the fellow eyes of patients with acute nonarteritic anterior ischemic optic neuropathy (NAAION) to those of control subjects.

METHODS

This study included 46 patients with NAAION matched for age, sex and refraction data (spherical equivalent and/or axial length) to 46 control subjects. The anatomical parameters assessed using the Cirrus SD-OCT were the mean RNFL thickness, in the 4 quadrants (inferior, nasal, temporal, superior) and according to the 12 hourly meridians, GCC mean and in 6 quadrants centered on the fovea (infero-nasal, supero-nasal, infero-temporal, supero-temporal, superior and inferior) and parameters of the optic disc (Cup ratio - Vertical and Average Disc, Rim Area, Disc Area, Cup Volume).

RESULTS

Compared to the control group, the eyes contralateral to those affected by NAAION showed a greater value of the area of the neuro-retinal rim (rim area), and a smaller vertical cup/disc (C/D) ratio, mean C/D, and cup volume than the control group. There was no significant difference between the two groups for peripapillary RNFL thickness and GCC parameters.

CONCLUSION

The absence of damage to the RNFL or GCC of the unaffected fellow eyes of patients with NAAION does not explain the perimetric damage. The eyes contralateral to those affected by NAAION are characterized by an overall size of the optic disc identical to those of the control subjects, but a smaller cup, a recognized risk factor for NAAION.

[Optic disc features on OCT in glaucomatous and normal black Africans]

PURPOSE

To determine the correlations between the size of the optic disc and glaucomatous defects in black Africans.

DESIGN

Retrospective observational study.

METHODS

The study was conducted over a two-year period from November 2014 to October 2016, based on records of black Togolese patients who had undergone optic nerve head (ONH) OCT or ganglion cell complex OCT for assessment of glaucoma. The population was divided into 3 groups (I, II and III) depending on the size of the ONH. The ONH was considered small (Group I) if its size was less than the mean -1 SD, medium (Group II) if its size was within 1 SD of the mean, and large (Group III) if its size was greater than the mean+1 SD. Glaucomatous lesions were qualitatively identified on RNFL and or GCC. The ONH parameters were compared in the 3 groups. The Chi-square test was used to compare the percentages, and the t test to compare the means with statistical significance of 5%. The Pearson correlation coefficient (r²) was used to measure correlations.

RESULTS

A total of 586 eyes of 298 patients were examined, 314 glaucomatous eyes and 272 healthy eyes. The mean age was 41.0±15.7 [6; 86] years. There were 159 men vs. 137 women, with a sex ratio of 1.2. The mean surface area of the ONH was 2.80±0.55mm². Small ONH's (Group I) were defined as a surface area of less than 2.25mm², medium-sized ONH's (Group II) as an area between 2.25 and 3.35mm² and large ONH's (Group III) as an area greater than 3.35mm². Small ONH's represented 14.7%, (86 eyes), medium-sized 68.6% (408 eyes) and large ONH's 16.8% (98 eyes). The mean surface area of the neuroretinal rim, cup, the cup-disc ratio and the RNFL thickness were statistically significant in the 3 groups. Similarly, all these parameters were significant in groups of glaucomatous or non-glaucomatous eyes, except for the surface area of the cup. The RNFL thickness was weakly correlated with the surface area of the ONH (r²=0.39), moderately correlated with the surface area of the neuroretinal rim (r²=0.57). The surface area of the ONH was strongly correlated with the surface area of the cup (r²=0.7). The neuroretinal rim surface area was strongly correlated with the cup-disc ratio (r²=0.66).

CONCLUSION

The size of the ONH was correlated with the size of the cup, but it was not correlated to the surface area of the neuroretinal rim or the thickness of the nerve fibers. Analysis of the RNFL and GCC is essential for the diagnosis, especially in the case of large ONH's.

Study of perfusion changes in the optic disc of patients with fibromyalgia syndrome using new colorimetric analysis software

PURPOSE

We measured the amount of hemoglobin at the optic nerve head of fibromyalgia (FM) patients using new colorimetric analysis software. We also investigated whether perfusion defects of the optic nerve head in patients with FM lead to tissue atrophy and corresponding retinal nerve fiber layer (RNFL) thinning measured by optical coherence tomography (OCT).

METHODS

We recruited for this cross-sectional study 118 FM patients and 76 sex- and age-matched healthy controls. All subjects underwent a complete neuro-ophthalmologic examination, which also included visual field testing using the Spark strategy in an Easyfield perimeter, and OCT examinations using the Spectralis. One photograph of the optic disc was obtained using a Cirrus™ Photo 800 multi-modality imager. We analyzed fundus photographs using Laguna ONhE software, a new method that allows hemoglobin levels to be measured at the optic nerve head. We compared hemoglobin percentages in different sectors of the nerve head and RNFL thicknesses between the two groups.

RESULTS

Mean hemoglobin percentages and hemoglobin content in all optic nerve head sectors calculated by the Laguna ONhE program were significantly lower in FM patients than in healthy controls, and the main differences were detected in the outer ring, which corresponds with the neuroretinal rim. However, only the differences in the superotemporal RNFL were statistically significant. Correlations between the RNFL thickness and the percentage of hemoglobin in the different sectors were weak.

CONCLUSION

Optic disc perfusion was decreased in patients with FM, especially within the neuroretinal rim, without clear involvement in the RNFL.

[Screening method for angle closure and angle closure glaucoma using scanning laser polarimeter GDxVCC and photodynamic gonioscopy in a darkened room. One-year outcomes of systematic peripheral iridotomy]

INTRODUCTION

Angle closure glaucoma, a recognized major world health issue disproportionately affecting women and Asians, is not often considered in our European populations, normotensive subjects, myopic patients, or subjects with a deep anterior chamber. Early diagnosis is worthwhile, as laser peripheral iridotomy (LPI) is an effective one-step treatment of the causal mechanism.

PATIENTS AND METHODS

We have performed a retrospective study of patients who underwent an LPI, the indication for which was based on "photodynamic" gonioscopy in a darkened room showing iridotrabecular contact in darkness. Such photodynamic gonioscopy was motivated by the presence of even minute defects in the nerve fiber layer as seen on the GDxVCC or the presence of a Van Herick sign (narrow limbal anterior chamber depth).

RESULTS

One hundred and three eyes of 103 patients underwent LPI and a minimum 1-year follow-up (mean follow-up almost 2 years). Mean age was 63.7±11.8 years, and women accounted for 63.1% of cases. The vast majority (78.6%) of patients had neither glaucoma nor ocular hypertension. There were 60.1% hyperopes and 39.9% myopes. Over half (57%) had a deep or a very deep anterior chamber. After LPI, there was immediate deepening of the limbal depth of the anterior chamber in 100% of cases. The aqueous humor that flowed forward was almost always viscous-looking. After 1 year, the IOP was 1.3mm Hg±2.4 lower (P<.001) (t test). All patients who had experienced morning headaches (44% of patients) were relieved of this symptom. GDxVCC after 1 year was clearly improved in 18% of cases, slightly improved in 20%, stable in 50%, slightly worse in 11% of cases, and clearly worse in 1%. Cases treated at an earlier stage had a better improvement in GDxVCC.

DISCUSSION

Our study shows frequent chronic angle closure in our European population even with deep anterior chambers. Absence of a Van Herick sign does not rule out angle closure at night. A photodynamic gonioscopy with the Goldmann three-lens mirror (to avoid unintentional indentation with the small diameter lenses in these normotensive eyes) should be performed in a darkened room. LPI is an effective one-step treatment of the underlying cause, that is particularly beneficial if performed early.