SALZMANNS NODULAR DEGENERATION
It is a non-inflammatory, degenerative process characterised by whitish-grey or bluish-white elevated sub-epithelial nodules in the superficial corneal stroma that are usually bilateral, mid-peripheral and slowly progressive. There is usually a clear area before the limbus. It can cause blurred vision if it occurs in central part blocking the visual axis. It occurs more often in women than in men. The nodules elevate the epithelium. Peripheral lesions tend to be vascularised and may look like pseudopterygium. Usually one to nine discrete para-central lesions, often in a circular array at areas of corneal scarring or at the junction of old corneal scars and clear cornea.Each nodule is separated from other nodules by clear cornea, and iron lines may outline each nodule. The underlying stroma may be vascularised but the nodules are not vascularised.
- Foreign body sensation.
- Pain if recurrent erosions occur.
- Decreased visual acuity.
Ocular surface disorders:
- Meibomian gland dysfunction.
- Phlyctenular keratitis.
- Dry eye disease.
- Rosacea keratitis.
- Vernal keratoconjunctivitis.
- Atopic keratoconjunctivitis.
- Interstitial keratitis.
- Exposure keratopathy.
- Thygeson’s superficial punctate keratitis.
- Recurrent corneal erosions.
- Extended contact lens use.
- Previous corneal surgery followed by actinic exposure, recurrent erosions, and chemical or thermal injuries.
- Previous ocular trauma.
One of the hypotheses suggests that enzymatic destruction of Bowman’s membrane results in migration and proliferation of keratocytes from the stroma, resulting in secondary deposition of extracellular matrix components in nodular areas.
- Salzmann’s nodules:Salzmann’s nodules are solitary or multiple white-to-grey or light blue nodules, elevated on the corneal surface, and located in the mid-periphery of the cornea. Each nodule is about 0.5 to 2mm in diameter and is not vascularised. In some cases, single or few nodules are present in one or more quadrants during routine ocular examination in asymptomatic patients, and sometimes, the nodules may invade the central zone. When multiple nodules are present, they have a typical circular arrangement and might be confluent in the advanced stages. A normal clear cornea between the nodules is a characteristic clinical feature.
- Iron pigment deposition lines:Iron pigment deposition lines in the epithelium may be seen around the base of the lesions, and there is no further extension of these degenerative changes.
- Recurrent corneal erosions:Recurrent corneal erosions may or may not be present.
- Corneal topography
- Anterior segment- Optical coherence tomography (AS-OCT)
- In vivo confocal microscopy
- Haematoxylin & Eosin (H&E) stain
- Light microscopy
- Irritation of ocular surface:The characteristic sub-epithelial nodules may irritate the ocular surface resulting in secondary recurrent corneal erosions, photophobia, blepharospasm and watering.
- Hypermetropic (hyperopic) visual changes:Salzmann nodules may create a relatively steepened mid-peripheral cornea and a flatter central cornea, resulting in hypermetropic visual changes.
- Peripheral corneal vascularisation:
Argentum Nitricum – pink in color. It causes the eyes to become red and swollen, and there may be associated itching and biting sensation in the eyes. In some cases, there is a sensation of dryness and heat in the eyes.
Arsenic Album – The burning in eyes is worse during the night, particularly after midnight. Along with this, marked dryness of the eyelids is present. The eyes become red and congested along with the above symptoms.
Belladonna – redness of the eyes. There is a heated sensation in the eyes along with dryness. In some cases, there may be a sand-like sensation in the eyes. There may be itching and scratching along with sensitivity to light.
Euphrasia – prominent itching and gritty sensation in the eyes. A sensation of having dust, sand, or hair in the eyes is markedly present. Burning and acrid lachrymation (tears) is another attending feature in cases of pterygium needing Euphrasia.
Nux Moschata – extends over the cornea. A sensation of fullness may be felt in the eyes, and the eyes may feel too dry in most cases.
Sulphur - sensation of a foreign body or sand in the eyes, along with a biting sensation. There may be occasional stitching or stinging in the eyes along with lachrymation in the open air.
Ammonium Bromatum – red and sore eyes. This redness and soreness is most marked during the morning. Another attending feature is a sand-like sensation the eyes along with smarting of the eyes.
Merc Sol – burning, itching, and redness of eyes. Burning in the eyes is most marked in the open air. Profuse burning lachrymation (tears) may also be present.