Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Clinical indications for intraocular lens power calculation: A prospective randomised study


Patients about to undergo cataract extraction were assessed clinically using several criteria to try and judge the necessity for biometry. The patients judged not to need biometry were allocated randomly to two groups, one of which had biometry.

The only significant clinical criterion for biometry was found to be the wearing of glasses since before the age of 30 years. Several unexpectedly high refractive errors occurred in the group of patients who did not have biometry. In the group of patients judged not to need biometry but allocated to the biometry group, refractive results were significantly better (nearer to target refractions) than in the unmeasured group.

Routine pre-operative biometry is probably the only way to avoid unexpected high ametropia, and it also improves the refractive results. There is however much room for improvement in the accuracy of biometry.


  1. 1

    Singh K, Sommer A, Jensen AD, Payne JW . Intraocular lens power calculations. A practical evaluation in normal subjects at the Wilmer Institute. Arch Ophthalmol 1987, 105: 1046–50.

    CAS  Article  Google Scholar 

  2. 2

    Thompson SM and Mohan-Roberts V . A comparison of post-operative results with and without intraocular lens power calculation. Br J Ophthalmol 1986, 70: 22–5.

    CAS  Article  Google Scholar 

  3. 3

    Percival P . Lens power calculation—is it necessary? Trans Ophthalmol Soc UK 1983, 103: 577–9.

    Google Scholar 

  4. 4

    Hillman JS . The selection of intraocular lens power by calculation and by reference to the refraction—a clinical study. Trans Ophthalmol Soc UK 1982, 102: 495–7.

    Google Scholar 

  5. 5

    Gregory PTS, Esbester RM, Boase DL . Accuracy of routine intraocular lens calculation in a district general hospital. Br J Ophthalmol 1989, 73: 57–60.

    CAS  Article  Google Scholar 

  6. 6

    Olsen T . Pre- and post-operative refraction with implantation of standard power IOL. Br J Ophthalmol 1988, 72: 231–5.

    CAS  Article  Google Scholar 

  7. 7

    Halliday BL . Calculation of intraocular lens power—results in practice. Trans Ophthalmol Soc UK 1986, 105: 435–40.

    Google Scholar 

  8. 8

    Wong D and Steele ADMcG . A survey of intraocular lens implantation in the United Kingdom. Trans Ophthalmol Soc UK 1985, 104: 760–5.

    Google Scholar 

  9. 9

    Hoffer KJ . Accuracy of intraocular lens calculation. Arch Ophthalmol 1981, 99: 1819–23.

    CAS  Article  Google Scholar 

  10. 10

    Singh M and Dahalan A . Significance of intraocular lens power calculation. Br J Ophthalmol 1987, 71: 850–3.

    CAS  Article  Google Scholar 

  11. 11

    Holladay JT, Prager TC, Ruiz RS, Lewis JW, Rosenthal H . Improving the predictability of intraocular lens power calculations. Arch Ophthalmol 1986, 104: 539–4l.

    CAS  Article  Google Scholar 

  12. 12

    Menezo JL, Chaques V, Harto M . The SRK regression formula in calculating the dioptric power of intraocular lenses. Br J Ophthalmol 1984, 68: 235–7.

    CAS  Article  Google Scholar 

  13. 13

    Hillman JS . The computer calculation of intraocular lens power. A clinical study. Trans Ophthalmol Soc UK 1980, 100: 222–8.

    CAS  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to S M Thompson.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Thompson, S., Mohan-Roberts, V. Clinical indications for intraocular lens power calculation: A prospective randomised study. Eye 3, 696–703 (1989).

Download citation

Further reading


Quick links