Visual field deficits after epilepsy surgery: a new quantitative scoring method

Abstract

BackgroundAnterior temporal lobectomy (ATL) as a treatment for drug-resistant temporal lobe epilepsy (TLE) frequently causes visual field deficits (VFDs). Reported VFD encompasses homonymous contralateral upper quadrantanopia. Its reported incidence ranges from 15 to 90%. To date, a quantitative method to evaluate postoperative VFD in static perimetry is not available. A method to quantify postoperative VFD, which allows for comparison between groups of patients, was developed.MethodsFifty-five patients with drug-resistant TLE, who underwent ATL with pre- and postoperative perimetry, were included. Temporal lobe resection length was measured on postoperative MRI. Percentage VFD was calculated for the total visual field, contralateral upper quadrant, or other three quadrants combined.ResultsPatients were divided into groups by resection size (< 45 and ≥ 45 mm) and side of surgery (right and left). We found significant higher VFD in the ≥ 45 vs. < 45 mm group (2.3 ± 4.4 vs. 0.7 ± 2.4%,p = 0.04) for right-sided ATL. Comparing VFD in both eyes, we found more VFD in the right vs. left eye following left-sided ATL (14.5 ± 9.8 vs. 12.9 ± 8.3%, p = 0.03). We also demonstrated significantly more VFD in the < 45 mm group for left- vs. right-sided surgery (6.7 ± 6.7 vs. 13.1 ± 7.0%, p = 0.016). A significant quantitative correlation between VFD and resection size for right-sided ATL was shown (r = 0.52, p < 0.01).ConclusionsWe developed a new quantitative scoring method for the assessment of postoperative visual field deficits after temporal lobe epilepsy surgery and assessed its feasibility for clinical use. A significant correlation between VFD and resection size for right-sided ATL was confirmed.

The application of functional imaging in visual field defects: a brief review

“…The distinct dispersion characteristics of ultrahigh field 7-T DWI allowed for the characterization of optic tract injuries in patients experiencing cross-compression prior to surgery, offering valuable insights into the prognosis of vision recovery. In another study, van Lanen et al ( 68 ) developed a quantitative scoring method to evaluate VFDs following anterior temporal lobectomy using static visual field tests. They evaluated the feasibility of this approach for clinical applications.…”

Magnetic resonance-guided laser interstitial thermal therapy vs. open surgery for drug-resistant mesial temporal lobe epilepsy: A propensity score matched retrospective cohort study

“…Additionally, visual deficits should be considered when performing TLE surgery. A recent study proposed a novel quantitative scoring method to assess postoperative visual field deficits after TLE surgery 30 . This method shows potential as a valuable addition to the routine presurgical evaluations before TLE surgery.…”

Ventrolateral temporal lobectomy in normal dogs as a counterpart to human anterior temporal lobectomy: a preliminary study on the surgical procedure and complications

“…The most common complications in this study were loss of the menace response and atrophy of the temporal muscles. Visual abnormalities and temporal muscle damage are also common adverse effects in humans [ 31 , 35 , 41 ]. However, their occurrence is thought to be an inevitable secondary iatrogenic effect when the benefits of surgery, i.e., liberation from severe seizures, are considered.…”

“…MRI and pathology confirmed that the sites of visual pathway damage in this study were mainly the optic tract and internal capsule. In human ATL, visual field defects are frequently reported as a postoperative complication, of which contralateral superior quadrantanopia is the most common symptom [ 4 , 41 ]. This deficit is caused by damage to the anterior portion of the optic radiation and anterior bending of the temporal radiation in the temporal lobe (Meyer’s loop).…”