Initial temporal field defect in Leber hereditary optic neuropathy.

PURPOSE: To determine the site of the initial field defect in patients with Leber hereditary optic neuropathy (LHON). METHODS: We studied nine eyes of nine consecutive LHON patients with the 11778 mitochondrial DNA mutation who had no visual loss (four eyes) or only minimal visual loss (five eyes). When unilateral visual loss was observed, Humphrey field analysis (HFA) (HFA 30-2 program and sometimes the HFA 10-2 program) was immediately and repeatedly performed on the better eye. RESULTS: For the 12 centralmost points in the visual field, a loss of sensitivity (P<0.02) was initially found in the upper temporal field of nine eyes and in the lower temporal field of three eyes. These results indicate that it was possible to detect the initial site of sensitivity loss in the centralmost temporal test points in all nine cases. The HFA 10-2 program confirmed the sensitivity loss in the temporal field in two cases. CONCLUSIONS: The centralmost temporal visual field appears to be the most susceptible site in eyes of LHON patients. This suggests that the most susceptible cells during the early stages of LHON are the retinal ganglion cells located in the corresponding region of the retina.

Prolonged constant eye misalignment leads to failure to develop binocular vision in childhood ocular myasthenia gravis.

PURPOSE: Variable eye misalignment and blepharoptosis in childhood ocular myasthenia gravis can lead to permanent binocular visual loss. However, a standard ophthalmologic intervention for this condition has yet to be fully established. This study investigated the influence of variable eye misalignment and asymmetric blepharoptosis on the development of binocular vision in childhood ocular myasthenia gravis. METHODS: The authors retrospectively reviewed clinical records of consecutive patients with childhood ocular myasthenia gravis whose age of onset was younger than 36 months and who had follow-up periods of more than 1 year. Five patients were enrolled and were treated medically with pyridostigmine or corticosteroids. Eye alignment, eye movements, and blepharoptosis were observed during the follow-up period. Stereoacuity was recorded before and at the end of follow-up using Titmus stereoscopic and major amblyoscopic tests. RESULTS: None of the patients had amblyopia or anisometropia, but all had blepharoptosis that improved within 2 weeks after medication was administered. There was only one case in which stereoacutiy failed to develop, and this patient had a long period of constant exotropia lasting 48 months. In the remaining four cases, there was constant exotropia lasting less than 4 months or intermittent exotropia throughout the follow-up period. All of these patients regained or maintained binocular vision. CONCLUSION: Prolonged constant eye misalignment may be attributable to impaired binocular vision, and prompt eye alignment may be necessary in childhood ocular myasthenia gravis. Therefore, treatment based on precise assessment by a neuro-ophthalmologist or pediatric ophthalmologist that evaluates even slight eye misalignment is essential in ensuring normal development of binocular vision.