Mohammed Iqbal1, Hosam Ibrahim Elzembely2, Omar M Said3. 1. Department of Ophthalmology, Faculty of Medicine, Sohag University, Sohag, Egypt. 2. Department of Ophthalmology, Faculty of Medicine, Minia University, Minia, Egypt. 3. Department of Ophthalmology, Faculty of Medicine, Fayoum University, Fayoum, Egypt.