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Show Journal of Neuro- Ophthalmology 14( 2): 122- 123, 1994. 1994 Raven Press, Ltd., New York Letters to the Editor Photophobia in Trigeminal Neuralgia To the Editor: Photophobia is defined as the painful intolerance of the eyes to exposure to light ( 1). In neurologic practice, migraine is the most common cause of photophobia. It may also be found in patients with meningitis, subarachnoid hemorrhage, or lesions in the optic nerve or chiasm ( 2). The physio-pathogenesis of photophobia has not definitely been established. The photophobia present in diseases of the eye has been ascribed to irritation of the trigeminal nerve at its origin in the conjunctiva, cornea, or anterior segment of the eyeball ( 1). Intraparenchymal lesions involving the trigeminal nerve system at the mesencephalic ( 3) or thalamic ( 4) level may also produce photophobia. Photophobia may be a prominent symptom in trigeminal neuralgia ( 1). However, photophobia is not mentioned as a symptom in recent works on trigeminal neuralgia ( 5,6) or diseases of the trigeminal nerve ( 7,8). To study the prevalence of photophobia and some of its features in trigeminal neuralgia, we sent a questionnaire to 157 patients with trigeminal neuralgia seen at the Lahey Clinic between January 1, 1985 and June 30, 1988. The responses of the 99 patients who returned their questionnaire and their clinical charts were reviewed. Pain in the distribution of the first division of the trigeminal nerve was present in 48 of the 157 ( 31%) patients. The mean age of the 67 women and 32 men who responded to the questionnaire was 67.6 TABLE 1. Photophobia and its features in trigeminal neuralgia No. of patients Photophobia 27/ 99 With first division trigeminal neuralgia 21/ 27 During attacks of pain 22/ 86" Between attacks of pain 12/ 81" Unpleasant 25/ 52" Painful 15/ 52" Mild 15/ 51" Tearing 12/ 47" Excessive blinking 6/ 58" " Number of patients responding to the question. years ( SD ± 11.3). Pain in the distribution of the first division of the trigeminal nerve was present in 42 of these 99 patients. Photophobia was present in 27 patients; 21 of the 27 had pain in the distribution of the first root ( p = .0007; chi- square test). Other features are listed in the Table. In summary, photophobia is a mildly painful and unpleasant symptom that sometimes occurs in patients with trigeminal neuralgia. The physio-pathogenesis of trigeminal neuralgia has not been determined. It has been suggested that irritation of the trigeminal nerve initiates ectopic action potentials and depresses central inhibition leading to paroxysmal discharges in the trigeminal nucleus and thus activation of nocioceptive neurons in the trigeminal, thalamic nucleus oralis ( 9). The cause of photophobia in trigeminal neuralgia is unknown. It was seen more often in patients with first- division trigeminal neuralgia. Photophobia has also been reported in patients with trigeminal nerve pathways involvement in the brainstem or thalamus ( 3,4). As originally suggested by Eckardt and Colleagues ( 10), we postulate that activation of peripheral or central trigeminal pathways during an attack of pain may converge with visual pathways and lower the threshold for visual impulses or activate visual pathways resulting in light being perceived as excessive. This convergence may occur in the upper mesencephalic- diencephalic junction. Jose A. Gutrecht, M. D. Irma M. Lessell, M. D. Lahey Clinic Burlington, Massachusetts REFERENCES 1. Miller NR. Photophobia. In: Miller NR, ed. Walsh and Hoyt's clinical neuro- ophthalmology, 4th ed., Vol. 2. Baltimore: Williams & Wilkins; 1985: 1099- 1106. 2. Safran AB, Kline LB, Glaser JS. Positive visual phenomena in optic nerve and chiasm disease: photopsias and photophobia. In: Glaser JS, ed. Neuro- ophthalmology, Vol. 10. St. Louis: CV Mosby; 1980: 225-^ 1. 3. Gutrecht JA, Lessell IM, Zamani AA. Central dazzle in trigeminal sensory neuropathy. Neurology 1990; 40: 722- 3. 4. Cummings JL, Gittinger JW Jr. Central dazzle: a thalamic syndrome? Arch Neurol 1981; 38: 372^ 1. 5. Maxwell RE. Clinical diagnosis of trigeminal neuralgia and differential diagnosis of facial pain. In: Rovit RL, Murali R, Jannetta PJ, eds. Trigeminal neuralgia. Baltimore: Williams & Wilkins; 1990: 53- 77. 122 LETTERS TO THE EDITOR 123 6. Henderson WR. Trigeminal neuralgia: the pain and its treatment. Br Med / 1967; 1: 7- 15. 7. Hughes RAC. Diseases of the fifth cranial nerve. In: Dyck PJ, Thomas PK, Griffin JW, Low PA, Poduslo JF, eds. Peripheral neuropathy. 3rd ed., Vol. 2. Philadelphia: WB Saunders; 1993: 801- 17. 8. Lecky BRF, Hughes RAC, Murray NMF. Trigeminal sensory neuropathy: a study of 22 cases. Brain 1987; 110: 1463- 85. 9. Fromm GH, Terrence CF, Maroon JC. Trigeminal neuralgia: current concepts regarding etiology and pathogenesis. Arch Neurol 1984; 41: 1204- 7. 10. Eckardt LB, McLean JM, Goodell H. Experimental studies on headache: the genesis of pain from the eye. In: Wolff HG, Gasser HS, Hinsey JC, eds. Research publications. Proceedings of the Association for Research in Nervous and Mental Disease, Vol. 23. Baltimore: Williams & Wilkins; 1943: 209- 27. J Neuro- Ophthalmol, Vol. 14, No. 2, 1994 |
