title: Optic disc height measurement with the Zeiss 4-mirror contact lens and 78 dioptre lens compared.
abstract: Measurements of optic disc diameter with the Zeiss 4-mirror contact lens and 78 dioptre (D) lens, made by projecting a slit-beam of known height onto the image of the disc, were compared with planimetric measurements in 30 eyes. The 78 D lens measurements were significantly larger than both the Zeiss lens and planimetric measurements (p < 0.0001 and p = 0.0047 respectively). The measurements using the Zeiss lens and planimetry did not differ significantly. Compared with planimetry, for the 24 eyes within 3 D of emmetropia, the correlation was greater for the Zeiss (r = 0.8591) than for the 78 D lens (r = 0.7148). The Zeiss lens also showed better agreement and less scatter of results compared with the 78 D lens (standard error of the mean +/- 0.0373 mm for the Zeiss and +/- 0.0418 mm for the 78 D lens). The Zeiss contact lens measurements of optic disc diameter show stronger correlation and better agreement with planimetry than measurements using a 78 D lens.
authors.affiliation: Department of Ophthalmology, University Hospital, Queen's Medical Centre, Nottingham, UK.
authors.forename: A F
authors.initials: AF
authors.lastname: Spencer
authors.forename: S A
authors.initials: SA
authors.lastname: Vernon
mesh_terms: D003261:Contact Lenses; D005901:Glaucoma / Q000473:pathology; D006801:Humans; D007909:Lenses; D008853:Microscopy / Q000295:instrumentation*; D015588:Observer Variation; D009798:Ocular Hypertension / Q000473:pathology; D009887:Ophthalmoscopy; D009898:Optic Disk / Q000033:anatomy & histology / Q000473:pathology*