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Editors Selection IGR 10-3
Perimetry: Multifocal IOLs and VF indices
Comment by Murray Fingeret on:
52993 Influence of multifocal intraocular lenses on standard automated perimetry test results, Aychoua N; Junoy Montolio FG; Jansonius NM, JAMA ophthalmology, 2013; 131: 481-485
The analysis of a single visual field printout is based upon the comparison of the scores at each test location to a normative database. The range of so-called normal scores varies based upon the person's age, test location (superior versus inferior) and eccentricity (central versus periphery). When a score falls outside of the expected range, it is flagged with a probability symbol based upon how significant the difference from expected is. The number of points flagged and how they are arranged are analyzed, determining the extent of loss and if the flagged points are localized or diffuse in their pattern. There are certain instances in which the field may show widespread depression that is not due to optic nerve or retinal damage. These include the presence of cataracts, small pupils, or if the wrong trial lens correction is used. The clinician must understand why the field is not clean and recognize when it is not due to an optic nerve/retinal problem. The authors describe another situation in which diffuse loss occurs; when diffractive multifocal intraocular lenses have been implanted. They found a -2 dB overall visual field depression with the use of multifocal IOLs. The authors included in their study a phakic control group and a monofocal IOL group, with the groups age matched. Diffuse loss was not seen when standard IOLs were used.
The clinician must recognize when multifocal IOLs have been implanted, and understand that mild diffuse loss may be caused by the use of a multifocal IOL and not some other condition
The loss for the multifocal IOL group was widespread, affecting all points in the field equally. The significance of this paper is that the clinician must recognize when multifocal IOLs have been implanted, and understand that mild diffuse loss may be caused by the use of a multifocal IOL and not some other condition.
As these IOLs are more commonly implanted, clinicians will be faced with mild diffuse loss more often. While the situation could be corrected by the development of a normative database for individuals with multifocal IOLs, due to the cost and difficulty in developing such a database it is doubtful this will happen anytime soon. Also,
Individuals with glaucoma will require perimetry to be performed soon after cataract surgery with multifocal IOLs to create a new baseline
individuals with glaucoma will require perimetry to be performed soon after cataract surgery with multifocal IOLs to create a new baseline. This set becomes the comparison for all fields going forward.
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