In TCM, interstitial keratitis is referred to as hùn jīng zhàng (murky eye nebula). Any discussion of the treatment for interstitial keratitis needs to be prefaced with this admonition: When this disease is caused by a serious infection that is curable with Western medicine, antibiotics must be the frst line of treatment.

That having been said, for the primary case in this chapter, the disease is a sequelae of a herpes zoster infection that was unresponsive to Western drug therapy. The patient presents with a classic constellation of fre-toxin symptoms; the frst key to diagnosis is the acute onset the patient exhibits of heat and fuid injury, and the signs of excessive heat in the pulse and tongue.

The location of the disease is the second diagnostic key. The cornea is associated with the wind wheel in the five wheel theory. The herpes infection, an external pathogenic factor that enters through the wind wheel, creates liver-gallbladder fire to fame and atack the eye internally. This fre then afects the blood vessels. This can be understood easily using a Wēn Bìng (warm disease) model: a wei level pathogen (a viral infection on the skin) enters the body through the wind-wheel, progresses to the qi level (signs of internal heat and zang-fu involvement) and ultimately afects the blood level (blood vessel proliferation).

We can also understand this internal-external relationship by analyzing the formula. Yín Huā Jiĕ Dú Tāng is a relatively recent formula from the Experience Gainedin Treating External Sores ( Yáng Kē Xīn Dé Jí, 疡科心得集) writen in 1805. The original formula is a variation of Wŭ Wèi Xiāo Dú Yĭn (Five Ingredients Toxin-Removing Beverage), as the frst ingredients are jīn yín huā and zĭ huā dì dīng (Herba Violae). It is also a variation of Yín Qiào Săn (Lonicera and Forsythia Powder), as the next medicinal is lián qiào (Fructus Forsythiae). Finally, it includes mŭ dān pí (Cortex Moutan) and xījiăo (Cornu Rhinocerotis), which are paired in Xī Jiăo Dì Huáng Tāng (Rhinoceros Horn and Rehmannia Decoction). The relationships of the medicinals in the formula weave together principles of releasing the exterior, clearing wind heat, clearing toxic heat and clearing blood heat.

For this version of the formula, there are several strategic substitutions. Pú gōngyīng replaces zĭ huā dì dīng because it is more efective for clearing liver heat, mŭ dānpí and xī jiăo are replaced with chì sháo and yù jīn to clear the vessels, and huáng lián (Rhizoma Coptidis) is replaced with lóng dăn căo because it is specific for reducing liver fre and clearing the eyes. This is an excellent example of the fexibility and skill of the physician. He preserves the key actions and structural integrity of the formula, yet re-writes it to suit best the patient’s presentation.

By the second visit, the acute crisis has abated and patient has improved. The yin fuids have been injured from heat, so the formula is entirely re-evaluated. The physician prescribes Zī Yīn Jiàng Huŏ Tāng. This is a complex formula from the A CloseExamination of the Precious Classic [on Ophthalmology] ( Shĕn Shì Yáo Hán, 审视瑶函) by Fu Ren-yu.

[滋阴降火汤加减]

In this formula, shēng dì huáng, shú dì huáng, dāng guī, bái sháo and chuān xiōng nourish liver blood and enrich liver yin; mài dōng combines with gān căo to enrich yin and promote fluid production; zhī mŭ, huáng băi and huáng qín subdue fire and enrich yin; chái hú regulates liver qi.

For this case, chán tuì and mì méng huā are added to clear the eyes and reduce nebula. There is an unspoken subtext with the inclusion of tŭ fú líng. The medicinal clears fire poison, but is also known to be anti-syphilitic; thus, we know that the physician is concerned that the patient is infected and is attempting to treat the underlying disease.