Wednesday, November 19, 2008

- gonioscopy.

In the name of Allah

to know the principle of goniolens we

must know some important information.....

- There is an angle called critical angle which need  rays come from media of high refractive index to media of low refractive index at this angle no refraction occur.

- When rays come from the angle between cornea and  iris outward to air as it has total internal reflection as there is critical angle so don't released to air .
- Total internal reflection as rays fall with angle is more than critical angle.
- corneal R.I = 1.38
- Air R.I = 1.00

- Goniolens eliminates the total internal reflection by replacing the cornea-air interface  by a new geniolens-air interface that has  higher R.I (n=1.50) than
that of the cornea and the tear.

-uses :-
used for viewing the anterior chamber angle of the eye for evaluation, management and classification of  normal and abnormal angle structures which is important in glaucoma management and evaluation.

- Contraindications for gonioscopy:-

  • Hyphaema.
  • Compromised cornea (e.g corneal ulcer).
  • Lacerated or perforated globe.

Thanks alot

Dr Ibrahim


  1. Dr Ibrahim samaha
    السلام عليكم ورحمة الله وبركاته اجمل التهانى بمناسبة عيد الاضحى المبارك اعاده الله عليكم وجميع الاهل بالخير والبركة ، وجعلنا واياكم من الملبين فى العام القادم
    والسلام عليكم ورحمة الله

  2. Beram ElMasry
    كل سنة وحضرتك طيب وبخير وسعادة

    د إبراهيم

  3. Slam Allah Alaykum brother,
    Jazakum Allah Khaira for this blog. May Allah bless you.
    I love you in Allah.
    Brother, Osama, Montreal, Canada 12th Rabi Ola 1430 Hijri, 9th March 2009.
    Astwdeok Allah.

  4. Osama
    You are welome
    i love you in allah
    you are welcome.

  5. nice explanation about critical angle


Nice to see your comment here........