The ‘Oxygen Paradox’ of the crystalline lens: A perspective based on the ancient literature

Dear Editor

I read with great interest the recent study published in Global Journal of Cataract Surgery and Research in Ophthalmology (GJCSRO) evaluating combined silicone oil removal and cataract extraction. The authors correctly identify that the expedited progression of cataracts in vitrectomised eyes is significantly driven by ‘increased oxygen tension and oxidative stress’.^[1] I would like to offer a historical-physiological perspective from the Siddha tradition (a component of the AYUSH system) that provides an ancient correlate to this modern ‘Oxygen Paradox’.

The Tirumantiram, authored by the Saint Tirumular, describes the body as a synergistic machine driven by ten types of vital air (Dasavayu).^[2,3] Verse 653 of the Tirumantiram establishes the dominance of Thananjeyan Vayu, characterised as the ‘swelling’ or ‘expanding’ air (Veengal Kaatru).^[3] Historically and physiologically, Thananjeyan mirrors systemic oxygen (O₂) – the dominant element required for metabolism, yet also the agent responsible for post-mortem expansion and oxidative decay.

While Thananjeyan is vital for systemic health, Tirumular identifies it as a source of ailment for the lens in Verse 656:

(Kaṇṇil viyāti urōkam taṉañcayaṉ / Kaṇṇil ivvāṇikaḷ kācam avaṉallaṉ / Kaṇṇiṉil kūrmaṉ kalantilaṉ ātalāl / Kaṇṇiṉil cōti kalantatum illaiyē)

The text warns that if Thananjeyan (systemic air/oxygen) interferes with the eye, ‘Kasam’ (cataract) occurs and the ‘Sothi’ (the inner light or transparency of the eye) is lost because ‘Koorman’ (the protective air) failed to integrate. This suggests that the lens requires Koorman Vayu – a specialised protective agent – to maintain its transparent state.^[3]

Modern ocular physiology confirms that the crystalline lens is an avascular tissue that must maintain an extreme ‘hypoxic core’ (PO₂ <2 mmHg) to prevent the cross-linking of crystallin proteins.^[4] I hypothesise that Koorman represents the ancient descriptor for the eye’s specialised antioxidant systems (such as the glutathione pathway). These systems ensure that Thananjeyan (oxygen and its derivatives) is kept at bay.

The ‘intrusion’ of systemic air described in the Tirumantiram mirrors the modern clinical results seen after vitrectomy, where increased oxygen tension in the vitreous cavity exposes the lens to oxidative stress.^[5] Recognising these historical parallels reinforces the biological necessity of ocular hypoxia. It invites further investigation into traditional preventative practices, such as Netra Vyamam (eye exercises) and Pranayama (breathing exercises), which may help reinforce the eye’s natural ability to shield the lens from oxidative stress.