Triggered Electrooculography for Identification of Oculomotor and Abducens Nerves during Skull Base Surgery

Objective@#: Electrooculography (EOG) records eyeball movements as changes in the potential difference between the negatively charged retina and the positively charged cornea. We aimed to investigate whether reliable EOG waveforms can be evoked by electrical stimulation of the oculomotor and abducens nerves during skull base surgery. @*Methods@#: We retrospectively reviewed the records of 18 patients who had undergone a skull base tumor surgery using EOG (11 craniotomies and seven endonasal endoscopic surgeries). Stimulation was performed at 5 Hz with a stimulus duration of 200 μs and an intensity of 0.1–5 mA using a concentric bipolar probe. Recording electrodes were placed on the upper (active) and lower (reference) eyelids, and on the outer corners of both eyes; the active electrode was placed on the contralateral side. @*Results@#: Reproducibly triggered EOG waveforms were observed in all cases. Electrical stimulation of cranial nerves (CNs) III and VI elicited positive waveforms and negative waveforms, respectively, in the horizontal recording. The median latencies were 3.1 and 0.5 ms for craniotomies and endonasal endoscopic surgeries, respectively (p=0.007). Additionally, the median amplitudes were 33.7 and 46.4 μV for craniotomies and endonasal endoscopic surgeries, respectively (p=0.40). @*Conclusion@#: This study showed reliably triggered EOG waveforms with stimulation of CNs III and VI during skull base surgery. The latency was different according to the point of stimulation and thus predictable. As EOG is noninvasive and relatively easy to perform, it can be used to identify the ocular motor nerves during surgeries as an alternative of electromyography.

The Path to Glaucoma Diagnosis

PURPOSE: To evaluate the events leading to a diagnosis of glaucoma. METHODS: Medical records of 484 subjects (223 women, 261 men; mean age, 55.3 years) who visited a glaucoma clinic without previous glaucoma diagnosis were reviewed. Events were classified into: 1) glaucoma-related symptoms, such as ocular pain accompanied by intraocular pressure elevation or visual disturbance without other ocular abnormalities except glaucoma, 2) ocular examination by an ophthalmologist for other symptoms, 3) routine health examination, or 4) patient request due to family history of glaucoma. Ocular findings that suggested glaucoma and led to detailed glaucoma assessment were classified as: 1) an optic disc abnormality, 2) high intraocular pressure, or 3) both. RESULTS: Events that led to the diagnosis of glaucoma were glaucoma-related symptoms in 11.8%, examination by an ophthalmologist in 74.2%, routine health examination in 12.4%, and family history in 1.7% of subjects. Findings that suggested glaucoma in ocular and routine health examinations were an optic disc abnormality in 84.2% and high intraocular pressure in 15.8%; both of these findings were found in 7.4% of subjects. CONCLUSIONS: The most common path to glaucoma diagnosis was optic disc assessment by an ophthalmologist and routine health examination. To facilitate early detection of glaucoma, regular detailed optic disc evaluation by an ophthalmologist should be emphasized.

Comparison of Eye Protection Methods of Ointment Instillation under General Anesthesia

PURPOSE: To compare the efficacy of 3 different eye ointment instillations with eyelid taping and eyelid taping alone to prevent eye complications during surgery under general anesthesia. METHODS: A total of 296 eyes of 148 patients who underwent general anesthesia for at least 60 minutes were randomly assigned to 1 of the following 4 groups: group A, eyelid taping alone; group B, eyelid taping with solcoseryl ointment; group C, eyelid taping with carbomer ointment; group D, eyelid taping with lanolin ointment. Schirmer test, tear film break-up time (TF-BUT), conjunctival hyperemia scale (CHS), National Eye Institute corneal staining scale (NSS), and ocular surface disease index (OSDI) were prospectively evaluated before and after general anesthesia. RESULTS: TF-BUT was significantly increased in the group B compared with the preoperative value (p = 0.035). CHS was significantly decreased in all 3 ointment groups (p < 0.05) after general anesthesia and the degree was significantly higher in groups B and C (p < 0.001). No corneal abrasion developed after general anesthesia. However, corneal erosion developed in 20 eyes of previously healthy subjects; 8 eyes (12.5%) in group A, 0 eye (0%) in group B, 2 eyes (2.5%) in group C, and 10 eyes (13.9%) in group D. The occurrence rates of new lesions were significantly lower in groups B and C (p = 0.035). CONCLUSIONS: Both eyelid taping alone and eyelid taping with eye ointment are effective protection methods against corneal abrasion during operation under general anesthesia. Eye ointment instillation together with eyelid taping shows not only improvement of subjective symptoms but also improvement of objective ocular surface parameters proving to be an effective ocular protection during general anesthesia.

Comparison of Eye Protection Methods of Ointment Instillation under General Anesthesia

PURPOSE: To compare the efficacy of 3 different eye ointment instillations with eyelid taping and eyelid taping alone to prevent eye complications during surgery under general anesthesia. METHODS: A total of 296 eyes of 148 patients who underwent general anesthesia for at least 60 minutes were randomly assigned to 1 of the following 4 groups: group A, eyelid taping alone; group B, eyelid taping with solcoseryl ointment; group C, eyelid taping with carbomer ointment; group D, eyelid taping with lanolin ointment. Schirmer test, tear film break-up time (TF-BUT), conjunctival hyperemia scale (CHS), National Eye Institute corneal staining scale (NSS), and ocular surface disease index (OSDI) were prospectively evaluated before and after general anesthesia. RESULTS: TF-BUT was significantly increased in the group B compared with the preoperative value (p = 0.035). CHS was significantly decreased in all 3 ointment groups (p < 0.05) after general anesthesia and the degree was significantly higher in groups B and C (p < 0.001). No corneal abrasion developed after general anesthesia. However, corneal erosion developed in 20 eyes of previously healthy subjects; 8 eyes (12.5%) in group A, 0 eye (0%) in group B, 2 eyes (2.5%) in group C, and 10 eyes (13.9%) in group D. The occurrence rates of new lesions were significantly lower in groups B and C (p = 0.035). CONCLUSIONS: Both eyelid taping alone and eyelid taping with eye ointment are effective protection methods against corneal abrasion during operation under general anesthesia. Eye ointment instillation together with eyelid taping shows not only improvement of subjective symptoms but also improvement of objective ocular surface parameters proving to be an effective ocular protection during general anesthesia.

Optic Cup Slope as a Numeric Representative of Glaucomatous Cupping

PURPOSE: To objectively define the degree of cupping, the authors extracted 3-dimensional slope surface maps from Cirrus HDTM-OCT data and assessed their differentiating characteristics between normal subjects and glaucomatous patients. METHODS: One eye from each of 40 normal subjects and 1 eye from each of 39 patients with glaucoma were examined using automated visual field perimetry and Cirrus HDTM-OCT. The Optic Disc Cube 200 x 200 protocol was performed. The individual OCT data were reconstructed as the 3-dimensional surface maps of the optic disc cup and the slope of each contour was calculated using custom-developed software. Several disc cup slope parameters were derived. The parameters measuring the internal features of the optic disc cup were calculated and compared between groups. RESULTS: Sum of cup slope, sum of thresholded cup slope, and sum of thresholded cup slope / thresholded cup area parameters were differentiating factors between the normal and glaucoma groups (p < 0.05). The area under the receiver operating characteristic curve (AUROC) value of the slope parameters ranged from 0.718 to 0.753. The sum of thresholded cup slope / thresholded cup area parameter was well correlated with visual field mean deviation (r = -0.250, p = 0.028). CONCLUSIONS: The optic disc cup slope parameter obtained with OCT may be a useful parameter for representing glaucomatous cupping.

Expression Profiles of F4/80 and Nestin in Ocular Immune Cells Following Pharmaceutically Induced Retinal Degeneration in Adult Mice

PURPOSE: To evaluate the expression patterns of F4/80 and nestin in the ciliary body and the optic nerve following N-methyl-N-nitrosourea (NMU)-induced retinal degeneration in adult mice. METHODS: After intraperitoneal injection of MNU (60 mg/kg) in adult mice, the eyes were enucleated at 2, 4, 7 and 30 days. Hematoxylin and eosin (H&E) stain, terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) stain and immunohistochemical stains of F/80 and nestin were performed. RESULTS: After MNU treatment, the photoreceptors were destroyed by cell apoptosis. According to immunohistochemistry, F4/80 and nestin were not co-expressed in the control group, but F4/80 was expressed within the ciliary body and optic nerve in the MNU-treated group; the expression of nestin also increased. In the outer nuclear layer, F4/80 and nestin co-expressing cells were observed. CONCLUSIONS: In response to retinal damage, the F4/80 and nestin co-expressing cells migrated to the retina from the ciliary body and optic nerve and were activated.