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Complex biometry: a new service development

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Session Details

Session Title: Cataract Surgery Outcomes

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 09:02

Venue: Capital Hall A

First Author: : R.Hussain UK

Co Author(s): :    M. Rubenstein   M. Mathew   S. Ghosh   V. Savant   J. Prydal  

Abstract Details


To analyse the outcome of a new local service development, the ‘Complex Biometry Clinic’.


Leicester Royal Infirmary, UK.


Retrospective data analysis of all patients referred to the Complex Biometry Clinic between October 2012 and October 2013. This clinic was set up to provide a one-stop solution for patients requiring non-standard biometry. The aim was to calculate optimal intraocular lens (IOL) power in complex patients using various techniques where conventional calculations with IOL Master or A-scan biometry were inadequate. The source of referral included the corneal team, other local consultants, in house hospital opticians and external referrals from other hospitals. Pre-operative and post-operative data was analysed. Biometric measurements were made using a range of techniques. Keratometry was performed using the Zeiss IOL Master, Javal-Schiotz keratometry, Zeiss Visante Topography, and contact lens over-refraction for determination of corneal power. Axial length was measured using the IOL Master, A-scan contact or immersion ultrasound, or B-scan ultrasound. When inconsistent results were obtained, measurements were repeated using several different techniques. A variety of formulae were considered in determining appropriate lens powers, and where necessary bespoke software was developed. In cases where biometry gave variable results, they were carefully reviewed to select a lens power that would give the safest refractive outcome wherever the true value lay within the measured range.


Over the recruitment period 40 patients were reviewed, although only in 35 were medical records available for analysis. Of these, 11 (31%) had a history of refractive surgery, 5 (14%) had had corneal transplantation, 7 (20%) had anomalous biometry recordings, 3 (9%) had keratoconus, 5 (15%) had corneal scarring with irregular astigmatism and 4 (11%) patients were referred for consideration of a secondary lens implant due to refractive surprise following phacoemulsification. Following review in the clinic, a spherical lens was implanted in 21 patients (60%), 6 (17%) had piggyback spherical or piggyback toric implants, 1 (3%) had a toric in-the-bag lens, 1 (3%) had a secondary sulcus lens implant and 1 (3%) had limbal relaxing incisions. Glasses or contact lens were prescribed as an alternative to surgery in 5 (14%). Of those who underwent surgery, 80% were within +/-1.00 dioptre of their targeted outcome, and 69% within +/-0.50 D. A good visual outcome was achieved in 81% with corrected visual acuity of 6/9 or better.


Patient satisfaction is dependent on a good refractive outcome of surgery, but biometric calculations can be problematic in those with coexisting ocular pathology, a history of refractive surgery, or for other sometimes unknown reasons. While our reported refractive outcomes do not match established values for standard biometry and cataract surgery, they are very acceptable considering the mix of complex patients selected for review in this new service.

Financial Interest:


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