Rigid gas-permeable (RGP) contact lenses are preferred over soft lenses in keratoconus primarily because:
- A They vault over the irregular cornea, creating a smooth anterior refracting surface via the tear lens, providing superior visual acuity ✓
- B They are more comfortable for long-term wear in all patients
- C They reduce corneal vascularization better than soft lenses
- D They have higher oxygen transmissibility than all soft lens materials
Correct answer: A. They vault over the irregular cornea, creating a smooth anterior refracting surface via the tear lens, providing superior visual acuity
Explanation
In keratoconus, the irregular corneal surface causes significant higher-order aberrations and poor vision with glasses. RGP lenses maintain a rigid anterior surface and the space between the lens and the irregular cornea fills with tears, which acts as a smooth refracting surface (tear lens), neutralizing corneal irregularities and providing dramatically improved visual acuity. Soft lenses conform to the irregular cornea and cannot provide this benefit. Scleral and mini-scleral lenses are now preferred for advanced cases.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.