Visual field screening with a laptop computer system

The aim of this study was to develop a visual field screening system and investigate the importance of using 2 different programs for visual field screening to be used in places in which other perimeters are yet not available. The system consists of a laptop computer with instructions for the patient displayed on the screen and additional equipment to ensure central eye position, eye distance to the screen, optimal optical correction, and light intensity. This visual field screening system combines a screening program consisting of 68 test points with the highest density in areas of high prevalence of visual defects, followed by a supplementary program comprising 82 other test points in a quadratic lattice pattern.

The system was compared with Octopus 1-2-3 threshold perimetry, and the applicability of the system when operated by optometrists was evaluated.

In the glaucoma clinic at the University Hospital, Rigshospitalet, Denmark, the screening program was used to investigate 98 patients (173 eyes) and to compare the results with those of the Octopus Perimetry Program dG2. The sensitivity of the system was 100% and the specificity was 78%. Subsequently, 18 optometrists in different locations in Denmark tested 1,022 patients (2,036 eyes). Patients contacted these optometrists because of the presence of refractive error, subjective vision problems, or eye symptoms. The screening was used as a part of a routine examination. In 432 eyes (21%), visual defects were detected using the screening program. By re-examining 349 eyes, with the addition of the supplementary program consisting of 82 other test points in a quadratic lattice pattern, the visual field defects were not reproduced in 263 eyes, a reduction of primary positive visual field defects by 75%. The additional supplementary program was not conducted with 38 eyes (2%) because of large visual field defects, high intraocular pressures, cataract, positive family history of glaucoma, lack of time, or poor patient cooperation. In 56 eyes (3%) examined with the additional supplementary program, the defects found in the screening program were reproduced. In total, 59 (5.8%) patients (38 + 56 eyes) were recommended to pursue an ophthalmologic eye examination by a local ophthalmologist.

Confrontation visual field testing in many places is the only method used for examining the visual field. A laptop computer system for visual field screening could be a better method for visual field screening in the primary eye care setting. For clinical relevance, it is necessary to perform the method with 2 different screening programs. The method can be useful as an important part of a routine examination and for directing further examinations.