The insights of Donguibogam align closely with modern medical understanding. Just as the classic text described the eyes as the window of the liver and kidney, modern medicine recognizes that glare and photophobia are rarely isolated to the eye alone, but are intimately tied to systemic health. In particular, it examines the nervous system of the eye, microvessels, and subtle dysfunction within the crystalline lens and retina.
Light scattering at night is especially common when the pupil dilates in dim settings. At such times, minute irregularities in the cornea or crystalline lens, or instability in the tear film, can scatter incoming light and degrade visual clarity. For example, dry eye syndrome leaves the tear film uneven, dispersing light instead of focusing it smoothly and thereby worsening glare. In the case of an incipient cataract, the crystalline lens gradually loses transparency, scattering light during transmission and serving as a classic contributor to glare and photophobia.
Just as Donguibogam speaks of liver deficiency, modern medicine explains the systemic effects of liver hypofunction on vision through blood circulation and nutrient delivery. Beyond detoxification, the liver manages circulating blood. When liver health falters, blood flow through the microvessels supplying the eyes can decrease or blood quality may decline, leaving ocular tissues short of essential oxygen and nutrients. This can lead to hypofunction of the optic nerve and damage to retinal cells, resulting in visual discomfort. Likewise, deficiency of kidney essence can be understood in terms of hormonal balance and aging. A decline in metabolic function and antioxidation capacity governed by the kidney accelerates ocular aging, impairing retinal function and causing diminished night vision or hypersensitivity reactions to light. Systemic conditions such as diabetes and hypertension can similarly damage the microvessels of the eye to induce retinopathy, leading to distorted vision or glare.
Ultimately, glare and photophobia reflect more than simple eye fatigue. They can arise from local concerns such as dry eye syndrome and incipient cataract, as well as broader systemic shifts involving liver and kidney hypofunction. Taking care of the entire body to restore internal balance remains an essential key to preserving eye health, demonstrating the enduring relevance of this classical wisdom.
