P. Juhani Airaksinen

Diffuse and Localized Nerve Fiber Loss in Glaucoma

To estimate the usefulness of photographs of the retinal nerve fiber layer in demonstrating glaucomatous neural tissue changes, we examined such photographs of 51 patients with glaucoma, 52 patients with ocular hypertension, and 29 normal individuals. The photographs were assessed in a masked fashion. A semiquantitative damage score was given in subsectors of the arcuate, papillomacular, and nasal nerve fiber bundle areas, separately for localized and diffuse loss of nerve fibers. The coefficients of variation of the reproducibility of retinal nerve fiber layer assessment were 0.22 for diffuse damage and 0.11 for localized damage. We detected abnormal retinal nerve fiber layer changes in 48 of the patients with glaucoma, in 27 of those with ocular hypertension, and in five of the normal control subjects. Generalized reduction of nerve fibers with or without localized defects was more common in patients with glaucoma than in those with ocular hypertension whose abnormal findings were primarily localized defects.

Neuroretinal Rim Area in Early Glaucoma

The neuroretinal rim area of the optic nerve head was measured in 33 normal individuals, 50 subjects suspected of having glaucoma, and 51 patients with glaucoma. The measurements were corrected for magnification produced by the optical system of the eye. The rim areas were statistically highly significantly different in these clinical groups. Mean neuroretinal rim area in the normal controls was 1.40 +/- 0.186 mm2. Therefore, 95% of the normal subjects had rim areas greater than 1.09 mm2; 30% of the subjects with ocular hypertension and 73% of the patients with glaucoma had rim areas less than 1.09 mm2.

Neuroretinal Rim Areas and Visual Field Indices in Glaucoma

Magnification-corrected measurements of neuroretinal rim area of the optic disk were correlated to visual field indices calculated from 49 thresholds of Octopus program JO. The indices express overall reduction and localized disturbances of retinal sensitivity. The study was composed of 123 subjects, including 23 normal subjects, 49 patients suspected of having glaucoma, and 51 patients with glaucoma. The neuroretinal rim area was highly significantly correlated with both visual field indices; the index for overall loss of retinal sensitivity had a somewhat higher correlation coefficient than the index expressing localized visual field changes. Adequate fit of visual field data on rim area was achieved by quadratic regression.

Color Vision and Retinal Nerve Fiber Layer in Early Glaucoma

We tested 47 eyes in 47 patients (ten normal subjects, 15 with suspected glaucoma, and 22 with glaucoma) with the Pickford-Nicholson anomaloscope to assess the retinal nerve fiber layer and measure color vision. The 47 subjects were randomly selected from a group of 132 for whom Farnsworth-Munsell 100-hue color error scores were known. The yellow-blue and green-blue anomaloscopic matching ranges correlated significantly with diffuse retinal nerve fiber loss. There was no correlation with localized retinal nerve fiber loss.

The Correlation Between Cup-Disk Ratio, Neuroretinal Rim Area, and Optic Disk Area Measured by the Video-Ophthalmograph (Rodenstock Analyzer) and Clinical Measurement

The video-ophthalmograph (Rodenstock analyzer) records the topography of the optic disk via simultaneous stereoscopic video images which are stored and analyzed with the help of a microcomputer. We performed a prospective study of 49 eyes of 49 patients to compare the vertical cup-disk ratio, the horizontal cup-disk ratio, the neuroretinal rim area, and the optic disk area obtained with the video-ophthalmograph with those obtained with manual analysis of black-and-white stereoscopic photographs. The correlation coefficients were 0.67, for vertical cup-disk ratio (P = .0000), 0.63 for horizontal cup-disk ratio (P = .0000), 0.72 for neuroretinal rim area (P = .0000), and 0.89 for optic disk area (P = .0000).

Correlation of retinal nerve-fiber-layer loss, changes at the optic nerve head and various psychophysical criteria in glaucoma

In 61 eyes of 61 patients with glaucoma, semiquantitative assessment of retinal nerve-fiber-layer (RNFL) loss and neuroretinal rim measurement of the optic nerve head by means of the Optic Nerve Head Analyzer were correlated to the outcomes of automated light-sense, flicker and resolution perimetry and the Farnsworth-Munsell (FM) 100-Hue test. A significant influence of age on total RNFL and total diffuse RNFL scores was found, but there was no measurable effect of age on neuroretinal rim area. Total RNFL and total diffuse RNFL scores showed a good correlation to the various visual field indices: total RNFL score vs mean flicker frequency as determined by flicker perimetry, r = − 0.606, P < 0.0001; total RNFL score vs mean sensitivity as determined by light-sense perimetry, r = −0.385, P=0.002; and total RNFL score vs mean ring score as determined by resolution perimetry, r = 0.341, P = 0.007. There was no significant correlation between RNFL scores and the FM 100-Hue score. Correlation between the neuroretinal rim area and the various psychophysical indices was poor and mostly not statistically significant. The high correlation of flicker scores with RNFL loss provides interest for future applications of this perimetric technique.

Capsule excision after failed Molteno surgery.

BACKGROUND AND OBJECTIVES To determine the frequency of scar tissue formation requiring surgical intervention after single-plate Molteno implantation and the outcome of excision of the encapsulated bleb. PATIENTS AND METHODS A retrospective study was performed on 95 eyes of 79 consecutive patients who underwent a single-stage Molteno implantation for refractory glaucoma. Fourteen eyes of 12 patients developed an encapsulated bleb. A successful outcome after bleb excision was defined as final intraocular pressure (IOP) between 6 and 22 mm Hg with the same amount of medication as preoperatively or less. RESULTS At the end of the mean follow-up of 30 months (range 8 to 75), the mean IOP (19.7 +/- 3.8 mm Hg) after bleb excision was significantly lower than the preoperative IOP (35.2 +/- 10.1 mm Hg; P < .001). The overall conventional success rate was 75%. CONCLUSION Excision of the encapsulated Molteno bleb offers an alternative in severely damaged eyes that have undergone several surgical procedures.

Diffuse Nerve Fiber Loss and Central Visual Function in Glaucoma

Retinal nerve fiber layer (RNFL) loss was assessed with a semi-quantitative scoring technique in 50 eyes of 50 patients. Twenty-three of 50 eyes (46%) had no diffuse nerve fiber loss, 27 of 50 (54%) had diffuse nerve fiber loss. Various foveal threshold criteria including temporal transfer, light-difference sensitivity and color vision were tested in all eyes. All of those functions were depressed in the presence of diffuse nerve fiber loss. These depressions were statistically significant for the high frequency end of the foveal temporal contrast sensitivity function (p = 0.0097), for foveal flicker fusion frequency (p = 0.0048), for foveal light-difference sensitivity (p = 0.0323) and for the blue on yellow sensitivity of the fovea (p = 0.0009), the average blue on yellow sensitivity of four parafoveal points (p = 0.0002) and the average blue on yellow sensitivity of 16 points in the central 10° (p = 0.0001). No statistically significant losses occurred for the low and intermediate frequencies of the foveal temporal contrast sensitivity function, for foveal light-difference sensitivity and the FM 100-Hue score. All temporal threshold criteria showed a very high specificity (87–100%) and positive predictive value (77–100%) for loss of RNFL, but the sensitivity was low (22–37%) as was the negative predictive value (52–54%). The best separation between eyes with and without diffuse nerve fiber loss was obtained by the high frequency end of the foveal DeLange-curve and foveal flicker fusion frequency. Whenever these parameters are abnormal the presence of diffuse nerve fiber loss is very likely.