Rudolf Guthoff - Academia.edu (original) (raw)

Papers by Rudolf Guthoff

Cornea, 2007

Purpose: To examine and compare the density and distribution of Langerhans cells (LCs) in the cor... more Purpose: To examine and compare the density and distribution of Langerhans cells (LCs) in the corneal epithelium of healthy volunteers and contact lens wearers. Methods: A total of 225 eyes of 130 healthy volunteers (age, 17-81 years) without history of ocular inflammation, trauma, or surgery and 98 eyes of 55 contact lens wearers (age, 13-76 years) were examined in vivo with the combination of the Heidelberg Retina Tomograph II and in-house-invented Rostock Cornea Module. Results: In healthy volunteers, in vivo confocal microscopy revealed LCs in 31% of all volunteers, with 37 of these 43 volunteers presenting LCs both in the center and the periphery of the cornea with densities of 34 6 3 and 98 6 8 cells/mm 2 , respectively. In the group of contact lens wearers, 55% of all corneas presented with LCs, and 11 of these 33 corneas revealed LCs at central and peripheral locations. Although LC densities were markedly higher in both the central (78 6 25 cells/mm 2) and the peripheral cornea (210 6 24 cells/mm 2) of contact lens wearers, the gradient of LC density from peripheral to central cornea was found almost identical in both groups. In the central cornea, LC density decreased with duration of contact lens wear. LCs were located at the depth of 35 to 60 mm (ie, the level of lower intermediate cells, basal cells, and subepithelial nervous plexus). LCs presented as either large cells bearing long processes or smaller cells lacking cell dendrites, most supposedly indicating mature and immature phenotype, respectively. Conclusions: In vivo confocal microscopy enables evaluation of LC density and distribution in corneal epithelium. LCs were found present both in the center and the periphery of the cornea without difference in distribution between healthy volunteers and contact lens wearers. However, contact lens wearers revealed almost twofold higher LC densities in both locations, implying chronic mechanical irritation of the cornea in response to the contact lens as foreign body. Taken together, analysis of LC using in vivo confocal microscopy provides helpful information for a better understanding of contact lensdisturbed ocular homeostasis.

Ophthalmologica, 2011

Purpose: Keratoconus is a predominantly bilateral form of corneal degeneration that is associated... more Purpose: Keratoconus is a predominantly bilateral form of corneal degeneration that is associated with central thinning and cone-shaped bulging of the cornea usually accompanied by a progressive reduction in visual acuity. A recent therapeutic option is cross-linking, a procedure designed to prevent the progression of keratoconus by the photochemical cross-linkage of collagen fibers. Patients and Methods: Eight eyes in 8

Optometry and Vision Science, 2013

Disability glare induced by headlights of oncoming cars has been associated with reduced quality ... more Disability glare induced by headlights of oncoming cars has been associated with reduced quality of vision. This study aimed at developing the Rostock Glare Perimeter to quantify dysphotopsia effects under simulated realistic conditions. Sixty phakic subjects of different ages were dazzled by a bright light source centered at a projection screen 3.30 m away from the subject's eye. Using a projected marker moving outward from the screen center with angular steps of 0.25° in 12 directions, the area where the subject cannot distinguish the white spot from the glare effects of the light source was determined. A corresponding mean radius in a field angle relative to the subject's eye was defined as a measure for disability glare. Monocular and binocular measurements were performed, and a separate repeatability and reproducibility study was executed to determine the precision of the Rostock Glare Perimeter. A significant mean positive correlation of disability glare with age (r = 0.534, p < 0.001) was found. The disability glare ranged from 0.33° to 1.8°, and a strong (r = 0.93, p < 0.0002) binocular summation effect was found. The repeatability and reproducibility limit of the Rostock Glare Perimeter method is 0.14° for 95% confidence interval. The Rostock Glare Perimeter method is sensitive to detect age-related disability glare differences and to find binocular summation for disability glare in a healthy population for small field angles with high angular resolution. These findings suggest that the Rostock Glare Perimeter method is a helpful device to quantify symptoms of glare.

Klinische Monatsblätter für Augenheilkunde, 2013

Pseudophakic dysphotopsia as unwanted side effect after cataract surgery are becoming increasingl... more Pseudophakic dysphotopsia as unwanted side effect after cataract surgery are becoming increasingly important. The so-called glare perimetry allows a realistic quantification of these phenomena. The article presents the method on the example of healthy subjects and pseudophakic patients. Using glare perimetry phakic and pseudophakic subjects were examined for differences in disability glare. For this, data from 60 phakic persons of different ages (45 ± 17.1 years) were used. As pseudophakic subjects 31 carriers of monofocal lenses (70 ± 6.7 years) and 25 carriers of multifocal lenses (71 ± 8.5 years) were tested. Disability glare was significantly smaller in the phakic group (1.00 ± 0.336°) than in the pseudophakic group (1.56 ± 0.622°). Among the pseudophakic eyes those with a multifocal lens (1.69 ± 0.367°) were significantly more sensitive to glare than those with a monofocal lens (1.43 ± 0.492°). Glare perimetry allows an objective quantification of effects of dysphotopsia under realistic conditions. Pseudophakic eyes show a higher sensitivity to glare than eyes with the natural clear lens. Here, eyes with multifocal lenses prove to be particularly sensitive to glare.

Cornea, 2007

Purpose: To examine and compare the density and distribution of Langerhans cells (LCs) in the cor... more Purpose: To examine and compare the density and distribution of Langerhans cells (LCs) in the corneal epithelium of healthy volunteers and contact lens wearers. Methods: A total of 225 eyes of 130 healthy volunteers (age, 17-81 years) without history of ocular inflammation, trauma, or surgery and 98 eyes of 55 contact lens wearers (age, 13-76 years) were examined in vivo with the combination of the Heidelberg Retina Tomograph II and in-house-invented Rostock Cornea Module. Results: In healthy volunteers, in vivo confocal microscopy revealed LCs in 31% of all volunteers, with 37 of these 43 volunteers presenting LCs both in the center and the periphery of the cornea with densities of 34 6 3 and 98 6 8 cells/mm 2 , respectively. In the group of contact lens wearers, 55% of all corneas presented with LCs, and 11 of these 33 corneas revealed LCs at central and peripheral locations. Although LC densities were markedly higher in both the central (78 6 25 cells/mm 2) and the peripheral cornea (210 6 24 cells/mm 2) of contact lens wearers, the gradient of LC density from peripheral to central cornea was found almost identical in both groups. In the central cornea, LC density decreased with duration of contact lens wear. LCs were located at the depth of 35 to 60 mm (ie, the level of lower intermediate cells, basal cells, and subepithelial nervous plexus). LCs presented as either large cells bearing long processes or smaller cells lacking cell dendrites, most supposedly indicating mature and immature phenotype, respectively. Conclusions: In vivo confocal microscopy enables evaluation of LC density and distribution in corneal epithelium. LCs were found present both in the center and the periphery of the cornea without difference in distribution between healthy volunteers and contact lens wearers. However, contact lens wearers revealed almost twofold higher LC densities in both locations, implying chronic mechanical irritation of the cornea in response to the contact lens as foreign body. Taken together, analysis of LC using in vivo confocal microscopy provides helpful information for a better understanding of contact lensdisturbed ocular homeostasis.

Ophthalmologica, 2011

Purpose: Keratoconus is a predominantly bilateral form of corneal degeneration that is associated... more Purpose: Keratoconus is a predominantly bilateral form of corneal degeneration that is associated with central thinning and cone-shaped bulging of the cornea usually accompanied by a progressive reduction in visual acuity. A recent therapeutic option is cross-linking, a procedure designed to prevent the progression of keratoconus by the photochemical cross-linkage of collagen fibers. Patients and Methods: Eight eyes in 8

Optometry and Vision Science, 2013

Disability glare induced by headlights of oncoming cars has been associated with reduced quality ... more Disability glare induced by headlights of oncoming cars has been associated with reduced quality of vision. This study aimed at developing the Rostock Glare Perimeter to quantify dysphotopsia effects under simulated realistic conditions. Sixty phakic subjects of different ages were dazzled by a bright light source centered at a projection screen 3.30 m away from the subject's eye. Using a projected marker moving outward from the screen center with angular steps of 0.25° in 12 directions, the area where the subject cannot distinguish the white spot from the glare effects of the light source was determined. A corresponding mean radius in a field angle relative to the subject's eye was defined as a measure for disability glare. Monocular and binocular measurements were performed, and a separate repeatability and reproducibility study was executed to determine the precision of the Rostock Glare Perimeter. A significant mean positive correlation of disability glare with age (r = 0.534, p < 0.001) was found. The disability glare ranged from 0.33° to 1.8°, and a strong (r = 0.93, p < 0.0002) binocular summation effect was found. The repeatability and reproducibility limit of the Rostock Glare Perimeter method is 0.14° for 95% confidence interval. The Rostock Glare Perimeter method is sensitive to detect age-related disability glare differences and to find binocular summation for disability glare in a healthy population for small field angles with high angular resolution. These findings suggest that the Rostock Glare Perimeter method is a helpful device to quantify symptoms of glare.

Klinische Monatsblätter für Augenheilkunde, 2013

Pseudophakic dysphotopsia as unwanted side effect after cataract surgery are becoming increasingl... more Pseudophakic dysphotopsia as unwanted side effect after cataract surgery are becoming increasingly important. The so-called glare perimetry allows a realistic quantification of these phenomena. The article presents the method on the example of healthy subjects and pseudophakic patients. Using glare perimetry phakic and pseudophakic subjects were examined for differences in disability glare. For this, data from 60 phakic persons of different ages (45 ± 17.1 years) were used. As pseudophakic subjects 31 carriers of monofocal lenses (70 ± 6.7 years) and 25 carriers of multifocal lenses (71 ± 8.5 years) were tested. Disability glare was significantly smaller in the phakic group (1.00 ± 0.336°) than in the pseudophakic group (1.56 ± 0.622°). Among the pseudophakic eyes those with a multifocal lens (1.69 ± 0.367°) were significantly more sensitive to glare than those with a monofocal lens (1.43 ± 0.492°). Glare perimetry allows an objective quantification of effects of dysphotopsia under realistic conditions. Pseudophakic eyes show a higher sensitivity to glare than eyes with the natural clear lens. Here, eyes with multifocal lenses prove to be particularly sensitive to glare.