Dr Sudhir Singh, MS
Sr. Consultant & Head
Department of Ophthalmology
JW Global Hospital Research Centre
Mount Abu India 302019
drsudhirsingh@gmail.com
Video
With Commentary : Neutralizing pre existing corneal
astigmatism (Toricity) by planning cataract surgery
incisions without toric IOLs.
Introduction
Intratunnel
phacofracture technique is a new technique of the manual
small incision cataract surgery (MSICS).In this technique
nucleus is broken inside the 4 to 6 mm wide sclero-corneal
tunnel with the help of the Lewis lens loop. The surgical
induced astigmatism (SIA) depends on incision size, shape
and site of the cataract surgery incisions. The SIA of 4 mm
to 8 mm sclerocorneal tunnel incision varies from 0.50 D to
3.00.The cataract surgery incisions are planned such a way
that can neutralize pre existing corneal astigmatism by SIA
without the costly toric IOLs. So manual cataract surgery is
also manual cataract refractive surgery.The Intratunnel
phacofracture technique was innovated by Dr Sudhir
Singh1,2.
Principles of
the Manual Cataract Refractive Surgery
Manual Cataract Refractive Surgery is
based on following principles:
1.Neutralizing pre existing corneal astigmatism (Toricity)
by planning cataract surgery incisions without toric IOLs.
2.Surgical induced astigmatism (SIA)
Induced multifocal vision by monofocal IOL
Surgical Induced
Astigmatism (SIA)
Post surgery
astigmatism is produced by incisions called as surgical induced astigmatism (SIA). SIA is related to incision
size, shape, location. The amplitude of the SIA produced
by intratunnel phacofracture is given table 1.
Pre operatively most of
the corneas have pre existed astigmatism (PEA) of various
amplitude.This PEA is effectively neutralized simply
choosing incision size and site (Table 2).On the contrary in
phacoemulsification we require costly toric intra ocular
lenses
Table 2:Pre pre existed
astigmatism neutralizing incision normogram
Surgically Induced
Astigmatism (SIA) Induced Multifocal Vision By Monofocal IOL
If surgical
induced astigmatism is planned such a way that there is a
simple myopic astigmatism of -0.75D to -1.25D vertical axis
or compound myopic astigmatism of -0.25 D Sph -1.00 Cyl at
vertical axis or compound myopic astigmatism of -0.50 D Sph
-0.75 Cyl at vertical axis or mixed astigmatism of +0.50 Sph
-1.25 Cyl vertical axis gives multifocal vision by a
monofocal IOL(Image1}.This SIA induce multi focal
vision free from side effects of the multifocal IOL like
halos, ghost images. So it eliminate the side effects and
heavy cost of the multifocal.
Image 1:SIA induce
multifocal vision illustration
Video Cases
References
1.Singh S.
First postoperative day visual outcome following 6 mm manual
small incision cataract surgery using intratunnel
phacofracture technique.
US Ophthalmic Review. 2014;7(1):26-30.
