We read with great interest the review article by Dr. Woung and associates.Citation1 They reviewed the recent important studies on optic neuritis in Asia, and compared them with those in Western countries. Their article included the studies addressed in Taiwan, Japan, India, and Singapore. However, several important studies in mainland China had not been included. We would like to review them in this letter.
Almost all the studies in Asia that were published in the English language investigated unilateral and bilateral acute optic neuritis (AON) simultaneously. In the Optic Neuritis Treatment Trial (ONTT), however, the investigators only recruited the patients with unilateral AON.Citation2 According to the literature, the proportion of bilateral AON in Asia is 25–33%.Citation3 It is unsuitable to mix bilateral and unilateral AON, and to compare them with ONTT due to the significantly different features of bilateral and unilateral AON. In mainland China, Dr. Du described unilateral and bilateral AON separately,Citation3,Citation4 and found that bilateral AON has some clinical differences from unilateral AON, including a higher prevalence of male cases and disc swelling, and more severe initial visual loss, but quicker visual recovery.Citation3
In our experiences, considerable Chinese patients with AON have a very poor visual prognosis.Citation4,Citation5 Dr. Lai and associates studied this subgroup of Chinese patients, and found that these patients have a high positive rate of anti-aquaporin-4 antibody (neuromyelitis optica immunoglobulin G),Citation6,Citation7 which is a highly sensitive and specific antibody in patients with neuromyelitis optica. For this reason, Dr. Lai’s studies had partly demonstrated the hypotheses proposed by Dr. Du, that a proportion of Chinese patients with AON might develop neuromyelitis optica during long-term follow-up, or might be a forme fruste of neuromyelitis optica.Citation8
Although most knowledge of clinical aspects of optic neuritis is from the Optic Neuritis Treatment Trial, some cases in the Optic Neuritis Treatment Trial also had poor visual recovery, and the reason remains unclear, which is similar to the situation clinicians in China have to face almost every day. We hope our colleagues in the world keep an eye on optic neuritis studies in mainland China.
Reply to “Keeping an Eye on Optic Neuritis Studies in Mainland China”
Pai-Huei Peng
Department of Ophthalmology, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
Correspondence: Pai-Huei Peng, MD, PhD, Department of Ophthalmology, Shin-Kong Wu Ho-Su Memorial Hospital, No. 95, Wen-Chang Rd, Shih-Lin District, Taipei, Taiwan, 100. E-mail: [email protected]
We appreciate the interest and comments by Dr. Ling and colleagues concerning our review of optic neuritisCitation1 and welcome the opportunity to respond to their concern.
The main purpose of our article was to elicit readers’ interest in optic neuritis since more and more discoveries have shed light on this major neuro-opthalmologic disorder. The scope of our review was focused on a comparison of certain characteristics of optic neuritis between Asian and Western countries. Therefore, the Optic Neuritis Treatment Trial was employed as a standard and the references cited are all published in English.
We are pleased that Dr. Du and colleagues have recognized some clinical differences between unilateral or bilateral acute optic neuritis in Chinese patients.Citation2,Citation3 We will retrospectively review our patients to clarify if they share the same features as those in mainland China as well.
In our review article, we did not address neuromyelitis optica in detail because we thought it would constitute a separate study. Dr. Ling’s letter provides a brief supplement on this issue. We hope the efforts of our colleagues will advance the understanding of this disease in the near future.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
REFERENCES
- Woung LC, Chung HC, Jou JR, Wang KC, Peng PH. A comparison of optic neuritis in Asian and in Western countries. Neuro-Ophthalmology 2011;35:65–72.
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- Du Y, Lin YC, He JF. The etiology of optic neuritis in Asian population. Med Hypotheses 2008;71:821–822.
REFERENCES
- Woung LC, Chung HC, Jou JR, Wang KC, Peng PH. A comparison of optic neuritis in Asian and in Western countries. Neuro-ophthalmology 2011;35:65–72.
- Du Y, Li K, Yang J, Xu X, Li JJ, Zhou RW, Zhang Y, Jiang BL, He JF. Bilateral acute optic neuritis: disc swelling and mild initial visual acuity loss may predict a better short-term visual acuity outcome. J Clin Neurosci 2012, in press. doi:10.1016/j.jocn.2011.10.020.
- Du Y, Yang J, Li JJ, Zhou RW, He JF. Unilateral optic neuritis in a Chinese population in three centers. J Clin Neurosci 2011;18:902–904.