Residue Astigmatism after Toric IOL Implanted

[uxuh]

I had an Alcon Toric IOL model T5 implanted in my left eye about 9 month ago. It targeted at Plano. However, my current eye glass prescription for my left eye is +0.75 and cyl 1.5. I am kind of disappointed for the astigmatism correction. It should be within cyl 0.5. I went to 2nd ophthalmologist and he used IOL master to measure the Cornea Astigmatism of my left eye and the result is cyl -1.88 D at 163 degree. If plot the data from IOL master into the acrysoft toric calculator, program would suggest IOL model T4 which has less power of correction than T5. I wonder if my left eye got over corrected. Can I do the Limbal Relaxing Incision for my left eye to reduce the astigmatism  Is the procedure safe?

[uxuh]

Hi Dr. Oyakawa:

Thank you for your video on You Tube. I used LRI Caculator to estimate the LRI arc need to correct my right eye to Plano. It was awful large .My right eye has cataract and astigmatism too and it has not been operated yet. The IOL master data is as follow:

AL: 24.95mm (SD=0.03mm SNR=2.7)
K1:44.23D/7.63mm@5°
K2:47.20D/7.15mm@95°
SE: 45.72D
Cyl: -2.97D@5°
R: 7.39mm (SD=0.00mm)
IOL(D):13.5

I used Acrysof IQToric IOL Calculator Online with Spherical equivalent 14 D, SIA 0.4D and the Toric calculator recommended SN6AT5 lens for me. What I am interested in is the anticipated residual Astigmatism left after surgery. I found the incision location makes difference. The data is as follow:

Incision location       residual Astigmatism after implant
180°                                       1.3D
225°                                       1.06D
250°                                       0.67D
270°                                       0.52D

I think I can live with 0.52D residue astigmatism after implant.  Is Incision location at 270° difficult for surgeon to operate on?  If Incision location is at 180°, how to calculate the arc for LRI, if I want implant and LRI to be done at the same time? What is the health rick if the LRI arc is too large?

[Ray T Oyakawa, MD]

The spherical equivalent of your prescription is Zero.  There your IOL is on target.  This can easily be fixed with a LRI.  You should have good uncorrected vision.

The astigmatism calculation after your surgery is not the same as before surgery due to the surgically Induced Astigmatism (SIA).  At this point the LRI calculation will be done on refracted astigmatism (NOT THE CORNEAL).  You should also look at LRIcalculator by AMO.  Just put in you astigmatism and no SIA.  You can use 42,00 for the flat axis and 43.5 for the steep axis (1.5 is the astigmatism). Also, use the refraction axis.

I also have a video on YouTube.  Google "Is an LRI needed......", Oyakawa, and Youtube.


Dr. O.