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Biomedical subjects

N Pfeiffer

Publications and source records attributed to N Pfeiffer.

At least 37 records · Page 2Linked to original sources
PubMed2002

Corneal tattooing: an alternative treatment for disfiguring corneal scars.

BACKGROUND: The performance and results of corneal tattooing are described in a case series of 11 patients suffering from a disfiguring corneal scar using a technique similar to conventional dermatography. METHODS: Drawing ink in different shades was applied into the anterior corneal stroma by punctures performed with a conventional spatula needle. RESULTS: Up to 4 years after surgery all patients still had satisfactory staining of the formerly cosmetically disfiguring corneal scar. CONCLUSION: Tattooing of unsightly corneal scars proved to be an efficient and easy to perform technique, yielding acceptable results during follow up.

Adolescent↗
PubMed2002

Ocular pulse amplitude in patients with open angle glaucoma, normal tension glaucoma, and ocular hypertension.

BACKGROUND/AIM: Intraocular pressure (IOP) is not a fixed constant value but rather has pulsatile components associated with cardiac action. The SmartLens dynamic observing tonometer (odc, Ophthalmic Development Company AG, Zurich, Switzerland) can measure and record simultaneously IOP and ocular pulse amplitude (OPA). It was the aim of this study to evaluate OPA in patients with primary open angle glaucoma (POAG) and high IOP, normal tension glaucoma (NTG), and ocular hypertension (OHT). Furthermore, the authors examined whether there were any correlations with blood pressure. METHODS: 80 subjects were divided into four groups (n=20): 20 patients each with POAG, NTG, and OHT and 20 volunteers without any ocular pathology except for cataract served as a control group. RESULTS: The OPA of the POAG group was not statistically significant different from the control group and from the OHT group. However, OPA was statistically significant lower (p<0.01) in the NTG group compared with all other groups. The OPA of the OHT group was slightly higher compared to the healthy volunteers (p=0.09) and to the POAG patients (p=0.09). No statistically significant correlations with blood pressure could be detected. A logistic regression model was established which identified OPA as an independent risk factor for NTG. CONCLUSIONS: The study demonstrated a decrease in OPA of patients suffering from NTG. Thus, measuring of OPA by the SmartLens dynamic observing tonometer could be helpful in the detection of NTG patients.

Adult↗
PubMed2001

[Innovative glaucoma therapy. Glaucoma therapy with topical carbonic anhydrase inhibitors].

Topical carbonic anhydrase inhibitors have been used since 1995 for medical glaucoma therapy, when dorzolamide was approved. In 2000, a second carbonic anhydrase inhibitor, brinzolamide, has become available in most of Europe. Both substances exhibit a comparable intraocular pressure-lowering activity, however, the side-effects are somewhat different. In the five years since its introduction, dorzolamide has had a positive risk-benefit-profile. In combination with any other topical agent, carbonic anhydrase inhibitors have an additive effect on the reduction of the intraocular pressure. Animal studies suggest that dorzolamide may improve ocular blood flow independent of the intraocular pressure; however, the significance for human glaucoma remains to be established.

Administration, Topical↗
PubMed2001

[Reproducibility of measurement of ocular pulse amplitude and intraocular pressure using Smartlens].

BACKGROUND: SmartLens (ODC Ophthalmic Development Company AG, Zürich) is a contact lens tonometer, which allows continuous registration of intraocular pressure (IOP) and ocular pulse amplitude (OPA) and simultaneous ophthalmoscopy. The purpose of this study was to evaluate the intra- and interobserver variability and reliability of intraocular pressure and ocular pulse amplitude measurements using SmartLens. METHODS: To evaluate the intraobserver variability, intraocular pressure (IOP) and ocular pulse amplitude (OPA) were both measured 5 times in 10 healthy eyes by one observer. To evaluate the interobserver variability, intraocular pressure and ocular pulse amplitude were measured by 3 different observers in 10 healthy eyes. Data description is based on coefficients of variation (SD/mean in %), statistical inference on ANOVA-based reliability estimation. RESULTS: The coefficient of the intraobserver variation was 9.57% for the IOP and 14.5% for the OPA (SD IOP: +/- 1.64 mmHg, SD OPA: +/- 0.39 mmHg). The coefficient of the interobserver variation with 5 replicate measurements was 10.16% for the IOP and 14% for the OPA (SD IOP: +/- 1.83 mmHg, SD OPA: +/- 0.4 mmHg). The interobserver reliability was 87% for the IOP and 86% for the OPA. One of the three observers obtained significantly higher IOP and OPA values. CONCLUSIONS: SmartLens is a reasonably precise and reliable device for IOP as well as OPA measurements but the results were not found to be observer independent.

Analysis of Variance↗
PubMed2001

[Keratopathy as a sign of multifocal congenital sensory polyneuropathy. A case report].

PATIENT: A 63-year-old female with bilateral recurrent corneal ulcerations for 10 years, suffered from vascularisation of the cornea and absence of corneal sensitivity. Other symptoms were multifocal hypoaesthesia with hypalgesia of hands and legs, generalised lack of deep tendon reflexes, absence of somato-sensory evoked potentials (SSEP) and of sensory nerve action potentials (SNAP) in these regions. A sural biopsy demonstrated extreme lack of myelinated fibres. Acquired causes for polyneuropathy were excluded. THERAPY: Subsequent to local ocular treatment we carried out a perforating corneal transplantation of the left eye because of corneal scars. This had to be repeated 2 years later because of vascularisation of the transplant. The visual function of the left eye could be stabilised at values between 0.2 and 1/50. CONCLUSION: Anamnesis and clinical symptoms of the patient are compatible with the diagnosis of hereditary sensory neuropathy type II (HSN II) affecting the trigeminal nerves. In patients with neuropathy and impaired corneal sensitivity, a favourable prognosis may be achieved by a corneal transplant.

Cornea↗
PubMed2001

[Refraction, anterior chamber depth, decentration and tilt after implantation of monofocal and multifocal silicone lenses].

BACKGROUND: We prospectively investigated changes in refraction, anterior chamber depth, decentration and tilt after implantation of multifocal (MIOL) and monofocal (MONO) intraocular lenses (IOL). PATIENTS AND METHODS: We examined 103 cataractous eyes from 103 patients receiving either a three-piece monofocal or multifocal silicone IOL. Anterior chamber depth (ACD), amount of IOL decentration, and degree of IOL tilt were quantified using retroillumination and Scheimpflug photographs. Examinations, including subjective refraction, were performed preoperatively, one week and 6 months postoperatively. RESULTS: All eyes were within 2 dpt (spherical equivalent) from the target refraction, and 93% of eyes with a MIOL were within 1 dpt. No significant refractive shift or ACD change occurred during the postoperative course. Median tilt in the MIOL group at 6 months was 1.1 degrees (0-2.6) and that in the MONO group 1.0 degree (0-2.5). There was no statistically significant change in intraindividual IOL decentration or tilt. CONCLUSION: Three-piece silicone MIOLs and MONOs with polymethylmethacrylate haptics implanted in the capsular bag after circular capsulorhexis provide good centration and very little tilt without statistically significant change up to 6 months after surgery. Postoperative refractive shift is of minor concern for 6 months after surgery.

Adult↗
PubMed2001

Clinical comparison of two intraocular pressure measurement methods: SmartLens dynamic observing tonography versus Goldmann.

PURPOSE: To compare intraocular pressure measurements obtained with SmartLens, a gonioscopic contact lens, to those from Goldmann applanation tonometry. METHODS: Eighty volunteers (20 healthy individuals and 60 glaucoma patients from the university eye hospital's outpatient department) were examined using conventional Goldmann tonometry and the new SmartLens tool. For each device three replicate measurements were performed. A paired t-test and the corresponding mean difference confidence interval approach were used to assess deviations in location of the two tonometric methods; the test procedure of Maloney and Rastogi was used for comparison of precision in paired data. Intraindividual differences were evaluated according to the approach of Altman and Bland. RESULTS: There was a mean difference of 5.6 mmHg (95% CI: 4.3 mmHg; 6.8 mmHg; P<0.01) in intraocular pressure between the two methods with a significant overestimation by SmartLens tonometry compared to Goldmann tonometry (P<0.01). The 95%-limits of agreement ranged from -5.4 mmHg to +16.6 mmHg for individual patients. The measurement method variance of SmartLens was higher (Maloney-Rastogi test; P <0.01). The mean coefficients of variation for intraindividual replicates were 10.1% (SmartLens) and 3.8% (Goldmann; P <0.01). CONCLUSIONS: Accepting Goldmann tonometry as gold standard for intraocular pressure measurement, the SmartLens method shows considerable variation and therefore is not proven to be an adequate substitute for Goldmann tonometry.

Adult↗
PubMed2001

Effects of intraocular cefotaxime on the human corneal endothelium.

PURPOSE: To ascertain whether 0.4 mL of cefotaxime 0.25% applied intracamerally causes toxic alteration of the human corneal endothelium. METHODS: In this prospective randomized masked study, 66 patients had cataract extraction using phacoemulsification, a frown incision, and implantation of a poly(methyl methacrylate) intraocular lens. This was followed by intraocular injection of 0.4 mL of cefotaxime 0.25% or balanced salt solution (BSS(R)). Contact specular microscopy and photography were performed preoperatively and 1 to 4 days and 3 months postoperatively. RESULTS: In the cefotaxime group, the mean endothelial cell count was 2729 cells/mm(2) +/- 474 (SD) preoperatively, 2520 +/- 462 cells/mm(2) 1 to 4 days postoperatively, and 2560 +/- 495 cells/mm(2) 3 months postoperatively. The mean endothelial cell count in the BSS (control) group was 2657 +/- 413 cells/mm(2), 2475 +/- 384 cells/mm(2), and 2486 +/- 427 cells/mm(2), respectively. There was no significant difference in cell count or morphology between groups (P <.05). CONCLUSIONS: Intraocular application of cefotaxime produced no significant changes in endothelial cell count or morphology when compared with application of a control substance. With its broad spectrum of antibiotic activity, cefotaxime might be an appropriate alternative to other intraocularly administered antibiotics in anterior segment surgery for prophylaxis and management of infection.

Adult↗
PubMed2001

Healon5 viscoadaptive formulation: Comparison to Healon and Healon GV.

PURPOSE: To compare the rheological characteristics of a viscoadaptive viscoelastic formulation with those of 2 standard ophthalmic viscosurgical devices (OVDs). SETTING: Department of Ophthalmology, Johannes Gutenberg-University, and Max Planck-Institute for Polymer Research, Mainz, Germany. METHODS: An independent comparative study of 3 OVDs of sodium hyaluronate (Healon(R), Healon GV(R), and Healon(R)5) was performed using the Advanced Rheometric Expansion System to analyze rheologic behavior (eg, dynamic frequency dependence of the complex viscosity) as well as rheological parameters (eg, viscosity at zero shear rate, pseudoplasticity, relaxation time, elastic and viscous modulus). RESULTS: Mean viscosity at zero shear rate was 243 Pas +/- 5 (SD) for Healon, 2451 +/- 12 Pas for Healon GV, and 5525 +/- 14 Pas for Healon5. Mean pseudoplasticity was 173 +/- 7, 754 +/- 10, and 591 +/- 6, respectively. Mean relaxation time was 21 +/- 3 sec, 83 +/- 4 sec, and 88 +/- 6 sec. At low shear rates, viscosity and elasticity (elastic and viscous modulus) increased from Healon through Healon5. Healon5 exhibited a dynamic behavior of the complex viscosity dependent on the duration of the shear rate exposure: At low shear rates, it slowly built up a high viscosity. At higher shear rates, it demonstrated a lower viscosity that decreased further during constant exposure to a specific shear rate. CONCLUSIONS: Healon5 had the highest viscosity and elasticity when exposed to low and high shear rates. These characteristics maintain anterior chamber depth. Also, the high viscosity of Healon5 exhibited a dynamic frequency dependence. In the presence of turbulence and phaco power (continuous high shear rates), it became dispersive by fragmentation and formed a cavity with an outer retentive shell. The cohesive and dispersive properties of Healon5 make it the best of the 3 OVDs evaluated for use at all stages of phacoemulsification.

Chemistry, Pharmaceutical↗
PubMed2001

Intraocular pressure after small incision cataract surgery: temporal sclerocorneal versus clear corneal incision.

PURPOSE: To compare intraocular pressure (IOP) after phacoemulsification and foldable intraocular lens (IOL) implantation using a temporal sclerocorneal or clear corneal incision. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: One hundred patients (100 eyes) with cataract having phacoemulsification with posterior chamber IOL implantation were randomly assigned to receive a temporal sclerocorneal or clear corneal tunnel incision. Intraocular pressure was measured preoperatively and 6 hours, 1, 2, and 3 days, and 5 months postoperatively. Statistical significance was determined by nonparametric group comparisons using 2-sample random Wilcoxon tests. RESULTS: Six hours postoperatively, the median IOP increase was significantly higher in the sclerocorneal tunnel group (57%) than in the clear corneal incision group (18%) (P <.001). No significant between-group difference in IOP was found at 1, 2, or 3 days or 5 months. At 5 months, IOP was 0.6 mm Hg lower than preoperatively in the sclerocorneal tunnel group and 1.5 mm Hg lower in the clear corneal group. CONCLUSIONS: After phacoemulsification and foldable IOL implantation, the immediate postoperative IOP increase was higher in eyes having a sclerocorneal incision than in those having a clear corneal tunnel incision. These results could be important in eyes with decreased outflow facility or preexisting optic nerve damage.

Adult↗
PubMed2001

[Near vision after implantation of monofocal versus multifocal intraocular lenses].

AIM: Object of this study was to compare the near visual acuity between eyes with monofocal intraocular lens (MONO) and myopic target refraction in comparison with eyes after refractive multifocal intraocular lens (MIOL) implantation and emmetropic to slight hyperopic target refraction. PATIENTS AND METHOD: 89 eyes of 83 patients underwent cataract surgery, in 49 eyes a MONO (SI-40NB, Allergan) was implanted, in 40 eyes a refractive MIOL (SA-40N, Allergan). At day 2 after surgery and after 5 months the uncorrected near visual acuity, the near visual aculty with distance correction and with an addition of +3 diopters (D) were determined. The refractive outcome targeted in case of MIOL implantation was emmetropia to slight hyperopia and myopia for the MONO subjects. The eyes with MONO were classified in 4 categories depending on their postoperative refractive error (spherical equivalent, SE): category 1 with SE +1 to > 0 D, category 2 with SE 0 to > -1 D, category 3 with SE -1 to > -2 D and category 4 with a SE -2 to > -3 D. RESULTS: We found a statistically significant better uncorrected near visual acuity in eyes with MIOL than in MONO subjects for category 1-3. In category 4 there was no statistically significant difference between MONO and MIOL. With best distance correction near visual acuity in MIOL was statistically significant better than in all 4 MONO categories. After adding 3 D, there was no statistically significant difference between the groups. CONCLUSION: Even in case of a myopic target refraction near visual acuity in eyes of the MONO group was statistically significant worse than in the eyes of the MIOL group. Only in case of postoperative SE of < or = -2 D eyes of the MONO group had a near visual acuity similar to the eyes of the MIOL group. This advantage is accomplished with a decrease in the uncorrected distance visual acuity.

Aged↗
PubMed2001

Update on topical carbonic anhydrase inhibitors.

Topical carbonic anhydrase inhibitors are a novel addition to the armamentarium of medical glaucoma treatment; dorzolamide has been available since 1995 and brinzolamide since 1998. They lower intraocular pressure by inhibiting carbonic anhydrase, a key enzyme for aqueous humor formation. Intraocular pressure-lowering activity of the substances appears to be the same and is similar to that of most other agents, but it does not reach the activity of the unselective beta-blocker timolol or the prostaglandin latanoprost. On concomitant treatment, additivity is reached with all other topical agents. A possible improvement of blood flow may offer an additional benefit, but its significance for the long-term outcome for human glaucoma remains to be shown. Side effects are mostly local. A more physiologic pH of brinzolamide appears to be advantageous.

Antihypertensive Agents↗
PubMed2001

The iris after prostanoid treatment.

Morphologic studies to date show that prostanoid-induced iris color change is not associated with any major pathologic process in the tissue. There is no evidence of melanocyte proliferation. The most likely mechanism for iris color darkening is increased melanogenesis, but this is not so marked as to cause any extensive release of melanin granules that might cause iris inflammation or even a pigmentary-type of glaucoma. Some patients, but not all, with color darkening have an apparent thickening of the anterior border zone; it remains to be established whether this is true thickening or merely if the anterior border is emphasized because of increased pigmentation.

Animals↗
PubMed2001

Effects of early postfiltration ocular hypotony on visual acuity, long-term intraocular pressure control, and posterior segment morphology.

PURPOSE: To determine whether hypotony after filtration surgery has any influence on visual acuity and intraocular pressure (IOP) lowering. PATIENTS AND METHODS: We prospectively investigated 43 eyes of 43 patients undergoing trabeculectomy without the use of antimetabolites for 12 months. RESULTS: The lowest postoperative IOP valued 4.9 +/- 3.6 mm Hg (range, 0-14 mm Hg). It correlated statistically significant with the IOP 6 weeks (P = 0.016), 6 months (P = 0.009), and 1 year after surgery (P = 0.027). Eyes with a deterioration of visual acuity 6 weeks after surgery had undergone a stronger postoperative hypotony (correlation with lowest postoperative IOP, P = 0.035). The mean period with an IOP less than 5 mm Hg was 3.5 +/- 8.0 days, and the mean period with an IOP less than 10 mm Hg lasted 45.4 +/- 68.8 days (range, 0-276 days). A hypotony score based on IOP and duration of hypotony was introduced. A correlation was detected between morphologic signs of hypotony, such as tiny retinal folds, at the 6-month follow-up and the duration of hypotony (P = 0.029) and hypotony score (P = 0.001). CONCLUSIONS: Hypotony after filtration surgery may decrease visual acuity in the early postoperative period. Conversely, early postoperative hypotony correlated with better long term IOP control. There was no deleterious effect on visual acuity after 6 months.

Adult↗
PubMed2001

Histological effects in the iris after 3 months of latanoprost therapy: the Mainz 1 study.

OBJECTIVE: To determine whether 3 months of topical latanoprost treatment caused proliferative or degenerative effects on the peripheral iris of patients with glaucoma. METHODS: Seventeen patients requiring filtering surgery for primary open-angle glaucoma or pseudoexfoliation glaucoma were randomized to receive topical latanoprost for 3 months (n = 8) or alternative medication (n = 9) before surgery. A trabeculectomy and a peripheral iridectomy specimen was obtained from each patient during surgery. The tissue was subjected to histological and immunohistochemical evaluation using 2 cell cycle markers: proliferating cell nuclear antigen and nuclear-associated protein (Ki-67). RESULTS: No degenerative or pathological changes were seen in the latanoprost-treated irides, including the one specimen in this series in which there was an eye color change. Proliferating cell nuclear antigen and nuclear-associated protein markers were negative for changes in all the test specimens. CONCLUSION: Short-term treatment with latanoprost does not produce morphological changes or cellular proliferation changes in the iris.

Administration, Topical↗