The photopic negative response of the blue-on-yellow flash-electroretinogram in glaucomas and normal subjects.

The photopic negative response of the flash-electroretinogram driven by the middle- and long-wavelength cones has been shown to be reduced in non-human primates with experimental glaucoma and in human patients with glaucoma. The photopic negative response for the blue-sensitive response has been studied using a blue-green silent-substitution-technique on a red background. The aim of this study was to re-evaluate the value of the photopic negative response of the blue-sensitive pathway in glaucoma using a conventional flash-electroretinogram. In 37 eyes of 37 controls (age: 53 +/- 13.6 years) and 37 eyes of 37 patients with open-angle glaucoma of different perimetric visual field defects (age: 58.3 +/- 10 years; MD: 11.7 +/- 6.7 dB) of the Erlangen glaucoma registry Ganzfeld flash-electroretinograms (LKC, UTAS 3000) were recorded using blue Xenon-flashes of increasing photopic luminance (0.013, 0.018, 0.030, and 0.052 cd s/m(2); 440 nm) on a bright yellow background (238 cd/m(2); 550 nm) after 2 min of light adaptation. Amplitudes and implicit times of the photopic negative response and of L&M-cone- and S-cone-driven b-waves were compared between glaucomas and controls for all flash energies (unpaired t-test). The amplitudes of the photopic negative response were significantly reduced in glaucoma patients for all flash energies (P < 0.001). The implicit times of L&M-cone-driven b-wave (0.013, 0.018, 0.030, and 0.052 cd s/m(2)) and S-cone-driven b-wave (0.030 and 0.052 cd s/m(2)) were significantly prolonged in glaucoma patients (P < 0.05). The changes in these implicit times, however, are very small (1.5 ms or less). The other measures did not differ significantly. The amplitude of the photopic negative response and the implicit times of the L&M-cone and S-cone b-wave in the same responses of the blue-on-yellow flash-electroretinogram are potentially useful in the evaluation of inner-retinal function in glaucoma.

Further investigation of the tolerance and mechanical adjustability of the *Acri.Tec AR-1 PC/IOL in rabbit eyes: an intraocular lens with reversibly adjustable optical power.

PURPOSE: To examine the tolerance and mechanical function of an adjustable intraocular lens (IOL) in rabbit eyes. METHODS: Implantation of the *Acri.Tec AR-1 PC/IOL into 14 rabbit eyes. Manipulation of the lens 8 weeks after implantation in order to change the refractive power. Follow-up for up to 5 months. Histopathologic examination of the eyes. RESULTS: Implantation and mechanical adjustment of the PC/IOL were possible. Eyes healed normally. No difference between eyes containing the *Acri.Tec AR-1 PC/IOL and eyes containing the control PC/IOL could be detected with respect to signs of inflammatory reaction, corneal transparency, intraocular pressure and histopathologic appearance. Histopathologic examination of the eyes showed that the *Acri.Tec AR-1 PC/IOL did not cause any damage in rabbit eyes. CONCLUSION: The *Acri.Tec AR-1 PC/IOL is well tolerated in rabbit eyes for extended periods of time, suggesting that this PC/IOL should be well tolerated in the long run. Surgical adjustment of the adjusting element can be performed with little effort several weeks after implantation.

Comparison between central corneal thickness and IOP in patients with macrodiscs with physiologic macrocup and normal-sized vital discs.

BACKGROUND: Macrodiscs with physiologic macrocups and elevated intraocular pressure (IOP) are frequently suspicious for glaucoma. Patients with an elevated c/d ratio and an IOP of more than 21 mmHg are often treated for glaucoma. We investigated a possible relationship between macrodiscs, IOP and central corneal thickness. METHODS: Using the Erlangen glaucoma registry, 341 out of 1,096 consecutive patients with unremarkable and repeated visual field (Octopus 500, G1-3, MD<2.1) were selected. Most of these patients had been sent as glaucoma suspects. The following data were collected: corneal ultrasound pachymetry (Tomey, AL-2000), IOP profile, visual acuity and central corneal power. The morphometric analysis was performed by planimetry using the Littmann formula. Optic nerve heads with a disc area of more than 3.1 mm(2) were defined as macrodiscs. RESULTS: Patients were subdivided into the following groups: group A: healthy macrodiscs, IOP <22 mmHg (87 patients); group B: healthy macrodiscs, IOP >21 mmHg (66 patients); group C: normal-sized healthy discs, IOP <22 mmHg (93 patients); group D: normal-sized healthy discs, IOP >21 mmHg (95 patients). Mean corneal thickness was: group A: 575+/-36 microm, group B: 596+/-37 microm, group C: 557+/-31 microm and group D: 585+/-38 microm ( P=0.003). Mean central corneal power measured: group A: 41.7+/-1.3 D, group B: 42.4+/-1.3 D, group C: 43.0+/-1.2 D and group D: 42.8+/-1.2 D ( P<0.05). The maximum of IOP was: group A: 17.6+/-3.1, group B: 26.2+/-4.1, group C: 17.2+/-3.4 and group D: 29.7+/-5.5 mmHg. Optic disc size measurements were: group A: 3.91+/-0.66, group B: 3.65+/-0.6, group C: 2.56+/-0.30 mm(2) and group D: 2.39+/-0.39 microm, respectively. CONCLUSIONS: Macrodiscs with elevated IOP have a higher corneal curvature (mean: +0.7 D) and a thicker central cornea (mean: +21 microm) compared to macrodiscs without elevated IOP. An exact evaluation of optic disc morphology in combination with pachymetric and keratometric measurements in relation to IOP could avoid an overtreatment in patients with suspect primary open-angle glaucoma.

Novel mutations in the MYOC/GLC1A gene in a large group of glaucoma patients.

Mutations at the myocilin (MYOC) gene within the GLC1A locus have been revealed in 2-4% of patients suffering primary open angle glaucoma (POAG) worldwide. In our ongoing glaucoma study six hundred eighty two persons have been screened for MYOC mutations. The first group consisted of 453 patients from a long-term clinical study diagnosed either with juvenile OAG (JOAG), POAG, ocular hypertension (OHT) or normal tension glaucoma (NTG) plus 22 cases of secondary glaucoma. This group, and additional 83 healthy controls, is part of a long term study with repeated clinical examinations at the University of Erlangen-Nurnberg. An additional sample of 124 glaucoma patients or at risk persons referred from other sources were included in the mutation screening. Five novel mutations, namely Gly434Ser, Asn450Asp, Val251Ala, Ile345Met and Ser393Asn, could be identified as cause of preperimetric POAG, JOAG, normal tension POAG and POAG. Myocilin mutations were identified similar with previous reports with other ethnic populations at the rate of 11/341 (3.2%) probands.

Testing for glaucoma with frequency-doubling perimetry in normals, ocular hypertensives, and glaucoma patients.

BACKGROUND: The aim of this study was to evaluate the diagnostic usefulness of the FDT perimeter protocol (C-20-5) in combination with a database system for analysis of single test locations. METHODS: One hundred seventy-three ocular hypertensive eyes, 116 "preperimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy, elevated intraocular pressure, no visual field defects in standard white-on-white perimetry), 199 "perimetric" open-angle glaucoma eyes (glaucomatous optic disc atrophy and visual field defects), and 151 control eyes underwent FDT screening and conventional white-on-white perimetry. Four repeated measurements were carried out in 15 glaucoma patients at 2-h intervals to judge reproducibility of all test locations. The present screening strategy begins testing at the normal 5% probability level. If a stimulus is not detected, further targets are presented. FDT-Viewfinder and statistics software were used for case-wise recalculation of all missed localized probability levels and correlation with corresponding test locations using conventional perimetry. RESULTS: Analysis of repeated measurements in patients reveals that variation of single test points can be considerable. However, the numbers of missed test-stimuli calculated globally or in quadrants are significantly correlated with corresponding Octopus visual field defects (Spearman rank correlation P<0.001). Using a predefined specificity of 96% in control eyes, 11% of ocular hypertensive eyes, 28.5% of "preperimetric" glaucoma eyes and 86.9% of "perimetric" glaucoma eyes have been classified glaucomatous using an overall score and with consideration of different cut-off points in right and left eyes. CONCLUSION: Point-wise analysis of FDT screening results can be helpful for classification of patient groups and consideration of the individual learning curve in repeated measurements. The C-20-5 protocol of the FDT perimeter is able to detect a considerable proportion of glaucomatous patients.

[Impact of cataract surgery on intraocular pressure after filtering operation due to primary open angle glaucoma and secondary glaucoma in pseudoexfoliation syndrome]. / Augeninnendruck bei Kataraktoperation nach filtrierender Operation wegen primärer Offenwinkelglaukome und sekundärer Offenwinkelglaukome bei Pseudoexfoliationssyndrom.

PURPOSE: To analyse the impact of cataract surgery after filtering operation on the intraocular pressure (IOP) due to primary open angle glaucoma (pOAG) versus secondary open angle glaucoma in pseudoexfoliation syndrome (PEX). The regulation of IOP was evaluated on the basis of criteria of advanced glaucoma intervention study (AGIS). PATIENTS AND METHODS: Retrospectively 95 eyes of 95 patients (53 x pOAG, 36 x clear cornea approach [group 1] and 17 x corneoscleral tunnel [group 2]; 42 x PEX, 30 x clear cornea approach [group 3] and 12 x corneoscleral tunnel [group 4]) were included. The IOP and antiglaucomatous eye drops were analysed before filtering operation, before cataract surgery and on average 33 months after cataract surgery. RESULTS: In all groups there was a significant reduction of IOP after filtering operation by 8.7 mm Hg on average and no significant difference of IOP before and after cataract surgery. At no time there was a significant difference in IOP between the four subgroups. According to criteria of the AGIS study 34 % of group 1, 29 % of group 2, 36 % of group 3 and 17 % of group 4 had an IOP lower than 14 mm Hg before cataract surgery. After cataract surgery only 31 % of group 1, 18 % of group 2, 13 % of group 3 and 8 % of group 4 met this criterion. CONCLUSION: On first glance sequential cataract surgery after filtering operation seems to have no clinically relevant impact on the IOP, neither with regard to the type of glaucoma nor in respect of the approach for cataract surgery. However, if IOP is evaluated based on the criteria of the AGIS, primary open angle glaucoma with clear cornea approach appears to yield superior results in contrast to secondary open angle glaucoma in pseudoexfoliation syndrome with corneoscleral tunnel concerning the regulation of intraocular pressure.