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Year : 2020  |  Volume : 32  |  Issue : 1  |  Page : 102

Dilemmas in preoperative ocular biometry calculations

Consultant Ophthalmologist, Ahalia Eye Hospital, Pattambi, Kerala, India

Date of Submission14-Feb-2020
Date of Acceptance15-Feb-2020
Date of Web Publication17-Apr-2020

Correspondence Address:
Dr. Rose Mary Tomy
Consultant Ophthalmologist, Ahalia Eye Hospital, Pattambi, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/kjo.kjo_16_20

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How to cite this article:
Tomy RM. Dilemmas in preoperative ocular biometry calculations. Kerala J Ophthalmol 2020;32:102

How to cite this URL:
Tomy RM. Dilemmas in preoperative ocular biometry calculations. Kerala J Ophthalmol [serial online] 2020 [cited 2020 Aug 12];32:102. Available from: http://www.kjophthal.com/text.asp?2020/32/1/102/282649

Dear Sir,

I heartily congratulate the KJO Editorial Board for the comprehensive coverage of ocular biometry in the past issue. The exhaustive “Intraocular lens power calculation in 2019: The cutting edge” by Mohan et al. and the excellent panel discussion on ocular biometry compiled by Sanitha Sathyan have certainly made the September–December 2019 KJO issue, a collectors' item for every cataract surgeon.

I would like to request your distinguished opinion on a few dilemma situations. As already described in your articles, the intraocular lens (IOL) power calculation is based on the measurements of the axial length of the eye, the refracting power of the cornea, and an estimate of anterior-chamber depth with the implant in place.[1]

  • In case of corneas with scarring or peripheral opacities, will you prefer the keratometry of the fellow eye or average the manual keratometry reading of the same eye?
  • Is any extra caution to be exercised in IOL power calculation in eyes that have undergone previous pars plana vitrectomy? Which IOL formula is preferable?

The recent development of optical biometric devices has improved the accuracy of biometric measurements. However, because estimated lens position (ELP) is affected by many parameters, including the preoperative capsule size, severity of the cataract, and postsurgical capsule contraction, accurate prediction is a challenging issue.[2]

  • With regard to the ELP, should 0.5 D be added to the IOL power for all mature, brown, intumescent cataracts?
  • When performing optic capture in the capsulorhexis for a sulcus-placed IOL, is a subtraction of 0.5-1 D preferred as for true sulcus placement?

Modern optical biometry with its low inter observer variability means that two surgeons measuring the same eye with the same device are likely to acquire almost identical measurements. Small-incision phacoemulsification techniques, with continuous curvilinear capsulorhexis and in-the-bag IOL placement, may reduce inter surgeon variability and its effects on refractive outcome.[3]

  • For surgeons who have access to only immersion ultrasound biometry, how would you recommend to go about determining the surgeon factor/surgically induced astigmatism and its application?
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Conflicts of interest

There are no conflicts of interest.

  References Top

Fyodorov SN, Galin MA, Linksz A. Calculation of the optical power of intraocular lenses. Invest Ophthalmol 1975;14:625-8.  Back to cited text no. 1
Tamaoki A, Kojima T, Tanaka Y, Hasegawa A, Kaga T, Ichikawa K, et al. Prediction of effective lens position using multiobjective evolutionary algorithm. Transl Vis Sci Technol 2019;8:64.  Back to cited text no. 2
Sahin A, Hamrah P. Clinically relevant biometry. Curr Opin Ophthalmol 2012;23:47-53.  Back to cited text no. 3


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