Scanning laser tomography in benign intracranial hypertension

Optical coherence tomography as an adjunctive tool for diagnosing papilledema in young patients

PURPOSE

The authors examined the peripapillary (3.4-mm diameter) retinal nerve fiber layer thickness (RNFL thickness) as depicted by optical coherence tomography (OCT) in young patients with pseudopapilledema or papilledema.

METHODS

In 17 consecutive patients (6 to 20 years old) with bilateral newly diagnosed papilledema or pseudopapilledema, the eye with the thicker mean global RNFL per patient was analyzed. Excluded were patients in whom cerebrospinal fluid opening pressure was between 190 and 250 mm H(2)O ("gray zone"). RNFL thickness was compared in eyes with papilledema and pseudopapilledema using the Mann-Whitney U test.

RESULTS

Papilledema was clinically diagnosed in 9 patients and pseudopapilledema in 6 patients; 2 patients were excluded. Median RNFL thickness in the eyes with papilledema was greater than that of both eyes with pseudopapilledema and controls at all 12 clock hours. In all 9 patients with papilledema, RNFL was thickened contiguously for 8 to 12 clock hours above the upper 95% confidence interval limit of normal.

CONCLUSION

The peripapillary RNFL thickness as depicted by OCT was found to be a reliable adjunctive tool in the differentiation of newly diagnosed papilledema and pseudopapilledema in young patients. Larger cohorts are required to confirm these observations and conclusion.

Laser scanning tomography measurement of the extent of papilledema in the follow-up examination of patients with idiopathic intracranial hypertension

Object

The authors evaluated the characteristics of patients with idiopathic intracranial hypertension (IIH), and compared laser scanning tomography (LST) measurements of papilledema with the clinical parameters and cerebrospinal fluid (CSF) opening pressures obtained.

Methods

Twenty-four patients were included in this study; these individuals included 21 women and three men with a mean age of 35.5 ± 9.7 years and a mean body mass index (BMI) of 35.4 ± 8.3 kg/m2. The authors conducted a prospective follow-up study over a period of 12 months through a series of four consultations with each patient. These patients had a mean time to treatment of 6.2 ± 7.9 months and, at the time of diagnosis, suffered a mean of 2.8 ± 1.3 symptoms each. Laser scanning tomography of the optic disc revealed a mean global rim volume of 1.693 ± 1.662 mm3 and a mean height of 0.604 ± 0.306 mm. The mean CSF opening pressure was 31.3 ± 6.3 cm H20.

Results

During the follow-up period, all patients improved significantly with regard to clinical parameters (p < 0.001), BMI reduction (p < 0.001), and reduction of visual field deficits (p = 0.007); visual acuity remained unchanged. In all patients at each successive consultation, the CSF opening pressure was lower than it had been at the previous consultation (p = 0.001). Laser scanning tomography measurements demonstrated a statistically significant reduction in both optic disc parameters over the follow-up period (global rim volume, p = 0.044; mean height, p = 0.019). The CSF opening pressure and the LST measurements correlated significantly with the number of symptoms (CSF opening pressure, p < 0.001; global rim volume, p = 0.001; mean height, p < 0.001). The mean area under the receiver operating characteristic curve in detecting the presence of clinical symptoms was 0.87 for CSF opening pressure, 0.7 for rim volume, and 0.81 for mean optic disc height.

Conclusions

Laser scanning tomography measurements are useful for evaluating the degree of papilledema in patients with IIH and correspond well with clinical data and measurements of CSF opening pressure. If a diagnosis of IIH is established, LST measurements may replace repeated CSF opening pressure measurements in follow-up monitoring.

Imaging of the optic disc and retinal nerve fiber layer in acute optic neuritis

PURPOSE

To demonstrate whether optical coherence tomography (OCT-3) and scanning laser ophthalmoscopy (HRT-2) can be used to measure changes of the optic disc and peripapillary retinal nerve fiber layer (RNFL) in eyes with acute retrobulbar optic neuritis that have no clinically apparent optic disc swelling. To correlate these findings with presentation magnetic resonance imaging (MRI) of the affected optic nerve.

METHODS

Eight consecutive patients with acute retrobulbar optic neuritis, who had no prior optic neuritis in either eye, were prospectively investigated at presentation and at between 1 and 3 months with clinical examination, OCT-3, HRT-2. At presentation, MRI of the optic nerves were performed in 7/8 patients.

RESULTS

Compared to unaffected eyes, affected eyes without clinically seen optic disc swelling at baseline, there was a non-significant trend to increased thickness in the total RNFL, superior and nasal measurements. Baseline HRT in affected eyes showed smaller mean cup to disc ratio (p=0.003) and a smaller cup area (p=0.002) compared with the unaffected eye. The MRI-demonstrated optic nerve lesion did not correlate with OCT RNFL thickening or HRT decrease of the physiological cup. Follow-up imaging of the affected eyes showed normalization of HRT cup size parameters and OCT RNFL thickness (p<0.04). At follow-up, the temporal RNFL had thinning in 7/8 affected eyes (46.8 mum, p=0.021) compared with fellow unaffected eyes (57.8 mum), which did not change.

CONCLUSION

OCT-3 and HRT demonstrate mild RNFL thickening or optic disc swelling in acute optic neuritis, even when swelling is not seen clinically. OCT-3 appears to reveal measurable RNFL thinning in the temporal quadrant after retrobulbar optic neuritis, even though vision improves. RNFL imaging may be useful in future studies of residual injury after optic neuritis.

Laser scanning tomography of the optic nerve vs CSF opening pressure in idiopathic intracranial hypertension

The authors investigated 17 patients with idiopathic intracranial hypertension (IIH), correlating laser scanning tomography of the optic nerve with CSF opening pressure. The decrease in papilla volume and papilla height showed a linear correlation with the opening pressure of the CSF (r = 0.59, p < 0.001; r = 0.63, p < 0.001). If the CSF opening pressure is higher than 20 cm water, an increase of 5 cm water CSF pressure corresponds to a papilla volume increase of 0.95 mm3 as well as a papilla height increase of 0.34 mm.

Idiopathic "benign" intracranial hypertension: case series and review

Idiopathic "benign" intracranial hypertension is an uncommon but important cause of headache that can lead to visual loss. This study was undertaken to review our experience in the diagnosis and management of idiopathic intracranial hypertension, giving special attention to treatments used. A retrospective chart review was conducted on 32 patients diagnosed with idiopathic intracranial hypertension between 1984 and 1995. Subjects included 23 females and ranged in age from 2 to 17.5 years. Headache was the most common symptom, followed by nausea and vomiting, double vision, and visual loss. Papilledema was the most common sign. Others were VIth cranial nerve palsy and compromised visual acuity at or within 3 months of presentation. Management included administration of acetazolamide or corticosteroids, lumboperitoneal shunt, optic nerve fenestration, and repeat lumbar puncture. Treatment combinations were used in 40% of cases. During follow-up, headache, papilledema, and decreased visual acuity persisted for longer than 10 months in a significant number of patients. We conclude that idiopathic intracranial hypertension causes significant short- and long-term morbidity with no proven effective treatment available. A prospective study is needed to establish the indications for treatment and the efficacy of the treatments used.