A cataract is a clouding that develops in crystalline lens of the eye or its capsule. Cataract typically progress slowly to cause vision loss and finally blindness if not treated. Clinical types of cataract are based on etiology and location of opacity within lens structure.

 

Classified based on etiology

Age related cataract

• Immature senile cataract- partially opaque lens, disc view hazy
• Mature senile cataract - completely opaque lens, no disc view
• Hypermature senile cataract/ Morgagnian cataract- liquefied cortical matter

Congenital cataract

• Sutural cataract
• Lamellar cataract
• Zonular cataract
• Total cataract

Secondary cataract

Drug-induced cataract -corticosteroids

Traumatic cataract

• Blunt trauma- in which the capsule usually intact
• Penetrating trauma- in which the capsular rupture & leakage of lens material, It’s an emergency surgery for extraction of lens and leaked material to minimize further damage)

Based on the location of opacity within the lens

Anterior cataracts

• Anterior cortical cataract
• Anterior polar cataract
• Anterior subcapsular cataract

Nuclear cataracts

Because of hardness surgical removal is difficult. Based on the color on lens nucleus

• Grey
• Yellow
• Amber
• Brown/Black

Posterior cataract

• Posterior cortical cataract
• Posterior polar cataract- its importance lies in higher risk of complication because of posterior capsular tears during surgery)
• Posterior subcapsular cataract

After cataract

Posterior capsular opacification – this type of cataract develops usually within three months to two years after a successful extra capsular cataract surgery with or without IOL implantation.

Requires Nd: YAG laser capsulotomy procedure to restore optical clarity.