An investigation of the ocular toxic effects of levetiracetam therapy in children with epilepsy

The effect of epilepsy and anti-epileptic drugs on the anterior and posterior segment of the eye

CLINICAL RELEVANCE

Understanding the causes of visual symptoms in epilepsy patients is important for early diagnosis and taking precautions.

BACKGROUND

The aim of this study is to evaluate the anterior and posterior segment parameters in patients with generalized tonic-clonic epilepsy (GTCE).

METHODS

This retrospective study included 50 eyes of 50 patients with GTCE and 55 eyes of 55 healthy controls. For all participants, detailed ophthalmic examinations were obtained from the files of patients. Anterior segment parameters were measured using corneal topography and non-contact specular microscopy, and posterior segment parameters were measured using swept-source optical coherence tomography.

RESULTS

The mean age of the patients with GTCE was 43.3 ± 13.2 years, and in the healthy controls it was 47.6 ± 10.7 years (p = 0.405). In GTCE patients, 34 patients were treated with monotherapy (MT) and 16 patients with polytherapy (PT). Central macular thickness (CMT) was statistically significantly thin in GTCE patients (p = 0.001). The average and four quadrants (superior, inferior, nasal, temporal) retinal nerve fibre layer (RNFL) were thinner in GTCE patients than in the healthy controls, but there was no statistically significant difference (p > 0.05, all). The central corneal thickness was statistically significantly thin in GTCE patients (p = 0.04). Endothelial cell density (ECD), endothelial cell number (ECN), and average cell area (ACA) were statistically significantly lower in GTCE patients than in the healthy controls (p < 0.05, all). Although the CMT, average, and four-quadrants RNFL were thinner in the PT group compared to the MT group, no statistically significant difference was observed (p > 0.05, all). Total high-order aberrations (HOAs) were 0.6 ± 0.4 in the MT group and 0.4 ± 0.1 in the PT group (p = 0.01). ECD, ECN, and ACA measurements were observed to be lower in the PT group compared to the MT group, but no statistically significant difference was detected (p > 0.05, all).

CONCLUSION

There could be statistically significant differences between GTCE patients and healthy controls in anterior and posterior segment parameters. This situation may be due to the epilepsy itself or to the antiepileptic drugs.

Toxic optic neuropathy associated with lamotrigine and levetiracetam dual therapy

We report the case of an early adolescent male on lamotrigine and levetiracetam therapy with a 1-month history of progressive, bilateral, painless visual loss which resolved on cessation of lamotrigine. To our knowledge, we present the first case of lamotrigine and levetiracetam dual therapy associated with toxic optic neuropathy, supported by electrophysiology and optical coherence tomography (OCT) changes. Electrophysiology findings were consistent with retinal ganglion cell dysfunction, with bilateral optic nerve involvement. Macula OCT showed mild retinal ganglion cell loss in all inner quadrants bilaterally. This case highlights the importance of asking patients with epilepsy treated with lamotrigine and levetiracetam about visual problems and considering early dose reduction or cessation of treatment.

Effects of sodium valproate and levetiracetam on posterior segment parameters in children with epilepsy

PURPOSE

To evaluate changes in posterior segment parameters in pediatric patients with epilepsy using sodium valproate or levetiracetam monotherapy for at least 12 months.

METHODS

This study included 45 children with generalized epilepsy aged 6-17 years and 32 age- and gender-matched healthy subjects. The patients were assigned to three groups: Group 1 included patients using valproate monotherapy at a dose of 20-40 mg/kg/day, group 2 included patients using levetiracetam monotherapy at a dose of 20-40 mg/kg/day, and group 3 consisted of healthy controls. Peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer-inner plexiform layer (mGCIPL) thicknesses were measured using spectral-domain optical coherence tomography (OCT).

RESULTS

No significant differences were noted between the groups regarding age, gender distribution, visual acuity, spherical equivalent, and intraocular pressure (p > 0.05). The average and temporal, nasal, and superior quadrants RNFL values were significantly thinner in group 1 than in group 2 (p = 0.001, p = 0.023, p = 0.011, and p = 0.001, respectively) and group 3 (p < 0.001, p = 0.032, p < 0.001, and p = 0.001, respectively). The OCT parameters were similar in groups 2 and 3 (p > 0.05). A negative correlation was observed in group 1 between only the average mGCIPL and the treatment dose (r =  - 0.501). In group 2, no significant correlation was found between OCT parameters and the duration of epilepsy treatment, dose of treatment, and age at treatment onset values (p > 0.05).

CONCLUSION

These findings support that there is an association between sodium valproate treatment and the reduction of RNFL thickness in epilepsy. Levetiracetam treatment appears to be a safe option, but care should be taken regarding ocular side effects that may occur with long-term and high-dose use of sodium valproate.

Evaluation of ganglion cell complex and retinal nerve fiber layer thinning in epilepsy patients

Purpose

This study aimed to compare the perimacular ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (RNFL) thickness measurements of epileptic and healthy individuals.

Methods

The right eyes of 38 epileptic and 38 healthy individuals who had been using antiepileptic drugs (AEDs) for at least 1 year were included in the study. Central macular thickness, perimacular GCC thickness and volume, and peripapillary retinal nerve fiber layers were measured by optical coherence tomography (OCT) device. Perimacular 1, 3, and 6 mm circle diameters of Early Treatment of Diabetic Retinopathy Study (ETDRS.

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were selected for GCC measurements.

Results

In epilepsy patients, GCC was significantly lower in the 3 mm superior quadrant and 6 mm in all quadrants compared to the control group (P < 0.05). RNFL was significantly thinner in epilepsy patients only in the temporal-inferior quadrant (P < 0.05). There was no significant difference between the patients who received AEDs as monotherapy and polytherapy (P > 0.05).

Conclusion

We found that epilepsy patients had significant thinning in the GCC layers and temporal-inferior quadrant of RNFL compared to the control group. Our findings from the study show that early retinal changes in epilepsy patients, especially perimacular GCC layers, can be followed up with OCT.

Retinal ganglion cell complex and visual evoked potentials in levetiracetam treatment

PURPOSE

To examine central macular, RNFL (retinal nerve fibre layer), GCC (ganglion cell complex) thicknesses; and VEPs (visual evoked potential) in epileptic patients using levetiracetam for at least one year.

MATERIALS AND METHODS

Sixteen focal epileptic patients receiving levetiracetam monotherapy and 16 healthy subjects were included in the study. Central macular, RNFL and GCC thicknesses according to spectral domain OCT (optical coherence tomography); and VEPs parameters were compared between patients and healthy subjects.

RESULTS

The mean age of patient and control groups were 40 ± 16 and 38 ± 12 years respectively (p > 0.05). The patient group was on levetiracetam therapy for 64 ± 45 (12-168) months. Central macular thickness was thinner in the patient group (p = 0.008). There was no difference among groups regarding RNFL thicknesses. GCC thicknesses in all quadrants were similar among groups, except the superior quadrant; which was thinner in the patient group (p = 0.03). P100 amplitude in 30 min pattern was lower in the patient group (p = 0.04). N135 latency in 15 min (p = 0.03) and 7 min patterns (p = 0.01) was longer in the patient group.

CONCLUSION

Central macular and GCC thicknesses; and VEP parameters in patients receiving levetiracetam treatment may differ from healthy subjects.