Correlation of preoperative keratometry K1/K2 readings with one week postoperative residual astigmatism obtained in manifest refraction in 310 eyes implanted with ReSTOR +3 IOL correlated by automated keratometry

Session Details

Session Title: Pseudophakic IOLs/ Multifocals I

Session Date/Time: Monday 15/09/2014 | 16:30-18:30

Paper Time: 17:22

Venue: Boulevard A

First Author: : N.Ray INDIA

Co Author(s): :                  

Abstract Details

Purpose:

Assessment of pre existing astigmatism prior to planning phaco with multifocal IOL surgery is mandatory as any residual astigmatism postoperatively reduces quality of vision.K1/K2 readings by manual and automated keratometry is a basic preop test. The author wishes to assess the reliability of depending ONLY on preop keratometry, on - axis clear corneal incision,and effect of SIA (surgically induced astigmatism) to reduce pre existing astigmatism to enhance post operative visual outcome in multi focal IOL surgery in a centre with no advanced diagnostic facilities.

Setting:

Single centre ,retrospective study by single surgeon in a stand alone practice in Kolkata India.

Methods:

155 patients (310 eyes) included in the study had pre op manual and automated keratometry .No access was available to advanced diagnostics like IOL Master, Pentacam ,contrast sensitivity charts etc .Meticulous biometry was done with Ocuscan by two separate technicians and correlated with preexisting spectacles if any. 310 eyes were included in the study with strict exclusion criteria like no pre existing corneal pathology ,K1/K2 difference more than1.5D,previous LASIK / RK surgery,Dry eye disease etc. Depending on degree of astigmatism patients were divided into 4 groups. 58 patients were astigmatically neutral with 0 to 0.5 D to 1 D and ONLY 20 patients had a difference of >1 to1.5D.All patients with astigmatism more than 1.5 D were not motivated for Restor Multifocal IOL. 155 patients underwent routine 2.2 mm micro coaxial phaco. Clear corneal incision was placed meticulously on the steep axis with a metal keratome , aiming to partly neutralize the pre existing astigmatism with the SIA.No other per operative procedure like LRI was done . One week post operative the astigmatism was assessed both with retinoscopy auto refraction and subjective refraction.

Results:

The author analyses the reliability of the preop measurements ,SIA ,on axis incision to manage astigmatism in Restor patients in a clinic without advanced instrumentation.Subjective refraction was done at 1 week post op and patients were divided into 4 groups depending on residual astigmatism.(175patients had no cylinder error )49 patients had 0.25-0.5D, 68 patients had a cylinder of >0.5 to 1D and 18 patients had a residual cylinder of >1 to 1.5 D.The spherical equivalent SE when calculated showed 175 patients strictly Plano,82 patients had 0.25D,45 patients had a SE of >0.25- 0.5D and 18 patients had. SE > 1D. Although pre op astigmatism in 188 patients varied from 0-0.5 D ,post operatively at 1 week 224 patients accepted of 0-0.5 D Cyl on manifest refraction ( 175 patients strictly Plano )

Conclusions:

7 out of 20 patients with K1/K2 difference of 1-1.5 were left with more than 1D of astigmatism post op. By maintaining strict exclusion criteria,meticulous on steep axis incision and predictable SIA , reduction of preop astigmatism was reliable and consistent In 224 out of 310 eyes in 155 patients (72.26%)the post operative astigmatism was within 0.5 D and compatible with good vision of Log Mar 0.1 or 6/6 p when results were correlated with spherical equivalent.Better acceptance of a larger degree of astigmatism 1-1.5D in a single eye was better tolerated when the fellow eye was strictly Plano.

Financial Interest:

NONE