ABSTRACT
INTRODUCTION: The "Twinfield Perimeter" can be used for white-on-white and blue-on-yellow perimetry. Since the normative database which is used fort the calculation of the visual field indices for both strategies is based on data from white-on-white perimetric evaluations of normal persons using the "Tübinger Automatikperimeter", the validity of this approach may be questioned. In the study presented here we compared the correlation of white-on-white (W/W) and blue-on-yellow (B/Y) visual fields in glaucoma patients with a hemifield scotoma. PATIENTS AND METHODS: One eye each from 40 normal persons and from 40 glaucoma patients was included in the study. Both W/W-perimetry and B/Y-perimetry was performed using the "Twinfield Perimeter" (Oculus, Modell 56 900, Wetzlar, Germany). From the sensitivity values determined with the 30/2 strategy, we calculated the mean sensitivity (MS), mean deviation (MD) of the total field and of both hemifields (HMS bzw. HMD) separately. Normal values derived from the normal persons of the present study were compared with the normal values used by the Twinfield Perimeter. To determine the strength of the association of B/Y- and W/W-hemifield scotoma, we calculated the linear correlation coefficient (Pearson's R) between the HMD of B/Y und W/W-hemifields. RESULTS: MS of both glaucoma patients and normal persons were determined to be significantly higher for B/Y visual fields (14.17 +/- 4.15 and 20.97 +/- 3.56) when compared with W/W-visual fields (10.70 +/- 3.19 or 15.98 +/- 3.3). When normal values from the Twinfield Perimeter were applied, the MD for normal persons was calculated to be - 4.69 +/- 3.22 compared with 0 +/- 3.6 when the MD was calculated with the normal values from the study. For both normal values we confirm a strong correlation between HMD-values of W/W- and B/Y-visual fields. CONCLUSIONS: Since the mean sensitivity of B/Y visual fields is higher than the mean sensitivity of W/W visual fields, calculations of the MD of B/Y visual fields of glaucoma patients should be based on normative databases which are derived from B/Y visual fields of normal persons.
Subject(s)
Diagnosis, Computer-Assisted/instrumentation , Glaucoma, Open-Angle/diagnosis , Scotoma/diagnosis , Visual Field Tests/instrumentation , Aged , Aged, 80 and over , Equipment Design , Female , Humans , Male , Mathematical Computing , Middle Aged , Optic Atrophy/diagnosis , Optic Disk/physiopathology , Reference Values , Sensitivity and Specificity , Visual Fields/physiologyABSTRACT
OBJECTIVE: To compare detection rates of glaucomatous visual field defects (VFDs) between the conventional 6 degrees x 6 degrees stimulus grid and locally condensed target arrangements in morphologically suspicious regions. METHODS: A total of 66 eyes of 66 patients with glaucoma or patients suspected of having glaucoma (34 females and 32 males; age range, 14-85 years) were enrolled in this study. Individual, local target condensation was realized by fundus-oriented perimetry (FOP) using a campimeter and compared with the results of conventional automated perimetry (CAP), obtained with the Humphrey Field Analyzer (30-2 grid). RESULTS: Twenty-three of the 66 patients showed normal findings with both methods; 27 had concordantly pathological results. In 15 patients we obtained normal findings with CAP, whereas FOP revealed early glaucomatous VFDs. Only one patient showed VFDs with CAP, whereas FOP results were normal. Scotoma detection rates significantly differed between the 2 methods (P<.001, sign test). Test duration with FOP was more than doubled compared with CAP. When considering only FOP points coinciding with the 6 degrees spacing of the 30-2 grid, there was no longer a significant difference between FOP and CAP (P>.25, sign test). This indicated that the target pattern, rather than the perimetric device, was most relevant for detecting glaucomatous VFDs. Follow-up throughout a series of 3 subsequent sessions at 6-month intervals revealed repeatable results in more than two thirds of all eyes for both FOP and CAP. CONCLUSIONS: Fundus-oriented perimetry that uses individually condensed test grids significantly increases the detection rate of glaucomatous VFDs in morphologically conspicuous areas compared with CAP using equidistant (6 degrees x 6 degrees) target arrangements. Repeatability is comparable between both methods.
