Maximum visual impairment occurs in: (LQ)
1. If the corneal scar invotves only bowman’s menbrane is known as nebula;Q it is a light opauty
2. if rather more dense it is known as macula. if very dense and white it is known as leucoma. Q
3. A thin diffuse nebula covering the central pupillary area interferes more with vision than a strictly localized dense leucoma as long as the leucoma does not block the whole pupillary area.
4. The irregular refraction through the central nebula is more disturbing to the patient than no refraction through a small leucoma in the pupillary axis