1. IN THE NAME OF GOD Astigmatic correction before &during phaco emulsification Sh.Hanjani , M.D

2.  In modern phaco surgeons no longer seek to avoid inducing ast
 In modern phaco surgeons no longer seek to avoid inducing ast. but rather must address to reduce significant pre-existing cylinder.
Patients have now come to judge the success of their surgery largely by their refractive result.

3. 1- Placing the incision upon the steep meridian
 Several different methods may be employed to achieve this goal .
1- Placing the incision upon the steep meridian
2- Varying size and design of incision .
3- Relaxing incisions .
4- Toric intraocular lens .
5- Bioptics approach (excimer laser or other keratorefractive modality).

4. In conjunction with cataract surgery Incisional procedures can be used to reduce or eliminate astigmatism.  The most common incisional surgery for the correction of astigmatism associated with cataract surgery is the limbal relaxing incisions (LRIs).  LRIs for the correction of mixed ast. can be very safe , inexpensive , useful technique for surgeons experienced in incisional surgical techniques.

5.  Arcute incisions and transverse incisions are both placed in the steep meridian of the cornea.  Both techniques flatten the steep meridian of the cornea and cause steepening of the opposite meridian (coupling).  Although the coupling ratio can be quite variable,in general the meridian of the incision will flatten approximately 2 to 3 times as much as the opposite meridian will steepen.

7.  At study in eyes undergoing phaco , evaluated the efficacy of paired intraoperative arcuate keratotomy combine with 3.5 mm limbal steep axis clear corneal incision.  Arcute incisions were performed in the steep axis at 7 mm optical zone based on lindstrom nomogram ( after 8 weeks ).  Arcute group D (1.26 D)  S Arcute group D (0.48 D)

9. Limbal Relaxing Incisions
 The notion of Astigmatic relaxing incisions in cataract procedures : Osher mid
 For many years corneal incisions done at mm optical zone . Although effective , causes irregular ast.
 More recently , a number of authors have recommended moving these incisions out to the peripheral cornea .Indeed these LRI are proving to be a less demanding and more forgiving approach to Ast.

10. LRIs advantages - Technically , they are easier to perform .
- Less likely to cause a shift in the resultant cylinder axis (deminished need to centration).
- Technically , they are easier to perform .
- Patients generally report less discomfort.
- Coupling ratio ,(1:1 ratio) negligible change in spheroequivalent (no need to adjust the IOL power)
- Peripheral incisions are less powerful but are still capable of correcting up to 3-4 diopters.
 For these reasons more refractive surgeons now prefer LRIs for all patients.

11. ضمن عرض پوزش
بدلیل حجم بالای LECTUER ادامه اسلایدها امکان پذیر نمیباشد در صورت نیاز به ادامه لطفا به واحد سمعی و بصری مرکز آموزشی درمانی فیض مراجعه و یا با شماره تلفن داخلی 392 تماس حاصل نمائید
با تشکر