Stephan Kremmer

Scanning laser polarimetry, retinal nerve fiber layer photography, and perimetry in the diagnosis of glaucomatous nerve fiber defects

Abstractu2002Background: Retinal nerve fiber layer defects are part of early glaucomatous damage. In the present study, we compared the ability of retinal nerve fiber layer photography (NFP) and scanning laser polarimetry (SLP) to detect nerve fiber layer defects in glaucoma patients. Methods: Besides ophthalmological standard examinations, we performed NFP (Zeiss Ikon fundus camera 30°, green filter), SLP (GDx, 1.0.14 and 2.0.09, LDT) and automated perimetry (Oculus, Twinfield, 30°) in 150 glaucoma patients [74 with primary open-angle glaucoma (POAG) and 76 with normal-tension glaucoma (NTG)]. The perimetric results were evaluated according to a modified Aulhorn classification. NFP and SLP were graded according to Quigley. Results: In POAG, 42% of NFP and 5% of SLP were not evaluable. In NTG, 24% of NFP and 4% of SLP were not evaluable. In POAG, NFP and SLP revealed a direct agreement in 54.5%, and in NTG, 55%; there was a small dif-ference of one stage in 39.5% (POAG) and 41% (NTG). In POAG, NFP / SLP showed agreement with perimetric results in 35%/30% of cases and differences of one stage in 56%/58%. In NTG, NFP / SLP agreed with perimetry in 52%/48% of cases and differed by only one stage in 32%/39%. Larger deviations were found in less than 13% of the cases. Conclusions: NFP and SLP mostly showed good agreement or little deviation as to grading of nerve fiber layer damage. In clinical use, SLP has advantages over NFP because a higher rate of good-quality images can be obtained and pupils do not have to be dilated. Additionally, SLP measurements provide quantitative data and a large normative data base exists.

Scanning laser polarimetry in myopic and hyperopic subjects

PurposeTo investigate the effect of refraction error and axial length on retinal nerve fiber layer (RNFL) measurements as obtained by scanning laser polarimetry (SLP).MethodsBesides ophthalmological standard examination (refractive error, keratometry, visual acuity, slit-lamp examination, applanation tonometry, funduscopy), perimetry, axial length measurement by means of ultrasound, and SLP were performed. Seventy-five myopic eyes (between −0.75xa0D and −8.5xa0D), 24 hyperopic eyes (0.75xa0D–6.5xa0D) and 40 emmetropic eyes were investigated. SLP parameters were compared in the different groups.ResultsThe statistical analysis of the absolute thickness values of SLP revealed highly significant (P<0.01) reductions in average thickness, ellipse average, superior average, inferior average, and superior integral in both myopic and hyperopic eyes in comparison with the emmetropic control eyes. The amount of reduction was between 12.9% (inferior average; myopia) and 30.2% (superior integral; hyperopia). There were no significant differences between myopes and hyperopes. A significant linear correlation for many of the SLP parameters with the refractive error (spherical equivalent) but not with axial length was found in both the hyperopic and the myopic group.ConclusionsDespite a wide interindividual range, SLP measurement values decrease with increasing myopia and hyperopia. In clinical practice, such reduced RNFL thickness values should be viewed with the necessary caution and additional polarimetric signs for glaucomatous damage should be taken into consideration.

Influence of Cataract Surgery With Implantation of Different Intraocular Lenses on Scanning Laser Tomography and Polarimetry

PURPOSEnTo describe the influence of cataract surgery with implantation of different intraocular lenses on scanning laser tomography (SLT) and scanning laser polarimetry (SLP) and to measure the birefringent properties of intraocular lenses in a laboratory setting.nnnDESIGNnProspective cohort study.nnnMETHODSnThe influence of phacoemulsification cataract surgery with intraocular lens implantation (56 polymethylmethacrylate [PMMA; 31 Pharmacia/Upjohn 811 B and 25 Domilens Flex 60]; 25 hydroxyethylmethacrylate/methylmethacrylate (HEMA/MMA) [Technomed, Memory Lens]; 32 silicone [Allergan Si40]; 25 acrylic [Storz Hydroview]) on SLP and SLT measurements was evaluated preoperatively and 3 to 4 weeks postoperatively in 138 eyes of otherwise healthy patients. Lens opacities were classified according to the Lens Opacities Classification System III (LOCS III). Imaging was performed with TopSS and GDx (Laser Diagnostic Technologies, San Diego, California, USA) for SLT and SLP, respectively. Additionally, birefringent properties of intraocular lenses were measured in a laboratory setting.nnnRESULTSnOur results show that imaging with SLT and SLP is possible with lens opacity-induced visual acuity reductions down to 0.2 and 0.16, respectively. There were no significant differences in the topographic parameters assessed before and after cataract surgery with SLT. However, standard deviations between three within-session single measurements were smaller postoperatively. Nerve fiber layer patterns were similar before and after cataract surgery with SLP, whereas certain total nerve fiber layer thickness values were significantly higher postoperatively. As a consequence, the number is significantly lower in the Domilens Flex 60 group (P =.01) and in the Storz Hydroview group (P =.02), and with a tendency also in the other groups as well. Measurements with a high-resolution optical bench revealed no birefringent properties of the implanted lenses.nnnCONCLUSIONSnOur results indicate that after cataract surgery with intraocular lens implantation some SLP values are altered significantly, whereas SLT parameters are not influenced. These findings are of clinical interest, especially in the follow-up of glaucoma patients.

Substance P and opioid peptidergic innervation of the anterior eye segment of the rat: an immunohistochemical study

Recently discovered endogenous opioid peptides such as nociceptin are known to modulate neurotransmitter release of primary afferent neurons (especially substance P, SP) and they have also been demonstrated in peripheral nerve fibres. The aim of this study was to investigate the opioid peptidergic innervation of the anterior eye segment and to compare it with the innervation pattern of SP in order to shed light on the functional relationship between these peptides. Anterior eye segments of 20 rat eyes were cut in a tangential plane and the sections stained with antibodies against SP, nociceptin, nocistatin, endomorphin 1 and 2, leu‐enkephalin and met‐enkephalin. Sections of the spinal cord or brain were used as positive controls. Numerous SP‐immunoreactive nerve fibres were found in the conjunctiva, cornea, episclera, trabecular meshwork, iris and ciliary body. A weak staining for met‐enkephalin and leu‐enkephalin could only be found in the iris and anteriormost ciliary body. Nerve fibres immunoreactive for nociceptin, nocistatin, and endomorphin 1 or 2 could not be detected in any part of the anterior eye segment. It is tempting to speculate that the opioid peptidergic innervation of the anterior ciliary body may play a role in the modulation of intraocular inflammation.

Vogelspinnenhaare als Hornhautfremdkörper

A 22 year-old-man and owner of several tarantulas visited his ophthalmologist because of red itchy eyes. Additionally to kerato-conjunctivitis epidemica, uncommon hairs were found especially in his left cornea. Corrected visual acuity was 0.8. According to literature these spider hairs can induce granulomas in the meaning of ophthalmia nodosa, and even migrate inside the eye. Therefore we removed as many hairs as possible, but we left two, not to cause iatrogen perforation. The penetration depth was measured by laser tomography. Local steroids successfully prevented further granuloma formation. Regular ophthalmological controls are important to early detect possible changes, and if necessary to remove these hairs even from deeper corneal layers, in case by keratectomy. Language: de