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Publication
Featured researches published by Markus Knuf.
Graefes Archive for Clinical and Experimental Ophthalmology | 2017
Achim Fieß; Johannes Janz; Alexander K. Schuster; Ruth Kölb-Keerl; Markus Knuf; Bernd Kirchhof; Philipp S. Muether; Jacqueline Bauer
ObjectiveTo analyse macular retinal and choroidal layer thickness in former preterm and full-term infants and to assess associated perinatal influence factors and functional correlation.MethodsThis prospective controlled, cross-sectional, hospital-based study in a tertiary center of maximum care examined former preterm infants with a gestational age (GA) ≤ 32 weeks and full-term neonates currently aged 4 to 10 years. We investigated data from 397 infants, analysing total foveal retinal thickness and six distinct macular retinal layer and choroidal layer measurements via spectral-domain optical coherence tomography. Multivariable linear regression analysis was performed to investigate associations of layer thickness with GA and retinopathy of prematurity (ROP).ResultsTotal retinal thickness in the fovea was thicker in former preterm infants with GA ≤ 28 weeks and in those with GA between 29–32 weeks compared to full-term infants independently of ROP. Occurrence of ROP was also associated with increased foveal thickness. Ganglion cell layer together with inner plexiform layer (GCL+IPL) was thinner in infants with GA ≤ 28 weeks than in full-term infants at 1000 and 2000μm distance from the fovea, but no association with ROP was present. Similar results were found for the photoreceptor layer. Total foveal retinal thickness was associated with low visual function.ConclusionThis study identified low gestational age and ROP occurrence as main determinants for foveal thickening. Furthermore, thinned GCL+IPL measurements were associated with lower gestational age. This study highlights the prognostic value of these maturity parameters influencing retinal morphology, which may affect visual function.
Cornea | 2017
Achim Fieß; Ruth Kölb-Keerl; Markus Knuf; Bernd Kirchhof; Christiane Blecha; Isabel Oberacher-Velten; Philipp S. Muether; Jacqueline Bauer
Purpose: To compare the axial length and anterior segment alterations in preterm infants with and without retinopathy of prematurity with those of full-term infants. Methods: The Wiesbaden Prematurity Study investigated 503 participants of former gestational age ⩽32 weeks and gestational age ≥37 weeks now being aged 4 to 10 years. This study included 485 participants in the prospective controlled cross-sectional, hospital-based study with successful Pentacam Scheimpflug imaging. Anterior segment parameters, axial length measurements, and associated factors were analyzed. Results: Corneal thickness did not differ between former preterm and full-term infants. Significant differences were found between preterm and full-term infants now aged ⩽7 years for spherical equivalent, astigmatism, corneal diameter, and axial length. In preterm infants aged ≥8 years compared with full terms of the same age, we found a significant difference only in the corneal diameter. In multivariable analysis of the corneal diameter, we detected an association with birth weight and perinatal adverse events. Astigmatism correlated with birth weight and laser treatment, anterior chamber depth with birth weight, laser treatment and age at examination, and axial length with birth weight and age at examination. Conclusions: This study demonstrated altered axial length and anterior segment morphology in former preterm infants, especially in the first years of life. In addition, we observed that preterm infants seemed to catch up, so that the differences in ocular growth in terms of spherical equivalent, astigmatism, and axial length decreased within the first 8 years of life.
British Journal of Ophthalmology | 2017
Achim Fieß; Luka Christian; Johannes Janz; Ruth Kölb-Keerl; Markus Knuf; Bernd Kirchhof; Philipp S. Muether; Jacqueline Bauer
Purpose The aim of the study was to investigate peripapillary retinal nerve fibre layer thickness (RNFLT) in former preterm infants and full-term neonates using spectral-domain optical coherence tomography (SD-OCT). Methods The prospective, controlled, cross-sectional, hospital-based study in a tertiary centre with maximum care examined 503 infants with a former gestational age (GA) of ≥37 and ≤32 weeks now aged between 4 and 10 years. In total, we analysed 432 participants with successful circular peripapillary RNFLT OCT measurements. Main outcome measures were RNFLT correlations to GA, birth weight, occurrence of retinopathy of prematurity (ROP), perinatal adverse events as well as functional correlation. Results Global RNFLT was thinner in infants with GA ≤28 weeks compared with infants with GA between 29 and 32 weeks (p=0.024), and to full-term neonates (p=0.007) independent of the occurrence of ROP. Multivariable analysis revealed that RNFLT was positively associated with higher birth weight and GA. Furthermore, a decrease of RNFLT was related to reduced visual function in all peripapillary sectors. Conclusions The main factors for retinal nerve fibre layer thinning are low birth weight and low GA. In addition, decreased RNFLT was associated with reduced visual function. This demonstrates that preterm infants are at high risk for peripapillary RNFL damage associated with reduced visual function.
Investigative Ophthalmology & Visual Science | 2016
Achim Fieß; Luka Christian; Ruth Kölb-Keerl; Markus Knuf; Bernd Kirchhof; Philipp S. Muether; Jacqueline Bauer
Purpose The aim of the study was to investigate peripapillary choroidal thickness in former preterm and full-term infants with spectral-domain optical coherence tomography (SD-OCT). Methods Subanalysis of infants with successful peripapillary choroidal thickness measurements of a prospective, controlled, cross-sectional, hospital-based study in a tertiary center of maximum care. The study examined 503 infants aged 4 to 10 years at the time of examination. Infants were divided into different groups: group 1 born with gestational age (GA) ≥37 weeks, group 2 born with GA between 29 and 32 weeks without ROP (retinopathy of prematurity), group 3 born with GA ≤28 weeks without ROP, and group 4 born with GA ≤32 weeks and presence of ROP. Results Peripapillary choroidal measurements were available for 388 of 503 participants. No significant differences were found among the four groups for global peripapillary choroidal thickness. Multivariable analysis revealed no association with low GA, birth weight, ROP occurrence, perinatal adverse events, and logMAR visual acuity. Only infants born small for GA (SGA) revealed peripapillary choroidal thinning in the superior (P = 0.033) and nasal (P = 0.024) sectors compared with infants born appropriate for GA (AGA). Infants SGA had lower visual acuity than AGA infants (0.03 ± 0.07 logMAR SGA versus 0.01 ± 0.05 logMAR AGA; P = 0.029). Conclusions Our results indicate that prematurity itself does not affect choroidal thickness in the peripapillary region. Only infants born SGA revealed peripapillary choroidal thinning compared with AGA infants. Our data indicate that fetal growth restriction leads to choroidal long-term alterations in the peripapillary region.
Acta Ophthalmologica | 2018
Achim Fieß; Ruth Kölb-Keerl; Alexander K. Schuster; Markus Knuf; Bernd Kirchhof; Philipp S. Muether; Jacqueline Bauer
The objective of this study was to investigate the relationship between visual acuity, peripapillary retinal nerve fibre layer (pRNFL), retinal thickness at the fovea and other factors with the neurologic status of former preterm children.
Investigative Ophthalmology & Visual Science | 2017
Achim Fieß; Alexander K. Schuster; Ruth Kölb-Keerl; Markus Knuf; Bernd Kirchhof; Philipp S. Muether; Jacqueline Bauer
Purpose To compare corneal aberrations in former preterm infants to that of full-term infants. Methods A prospective cross-sectional study was carried out measuring the corneal shape with Scheimpflug imaging in former preterm infants of gestational age (GA) ≤32 weeks and full-term infants with GA ≥37 weeks now being aged between 4 to 10 years. The main outcome measures were corneal aberrations including astigmatism (Zernike: Z2-2; Z22), coma (Z3-1; Z31), trefoil (Z3-3; Z33), spherical aberration (Z40) and root-mean square of higher-order aberrations (RMS HOA). Multivariable analysis was performed to assess independent associations of gestational age groups and of retinopathy of prematurity (ROP) occurrence with corneal aberrations adjusting for sex and age at examination. Results A total of 259 former full-term and 226 preterm infants with a mean age of 7.2 ± 2.0 years were included in this study. Statistical analysis revealed an association of extreme prematurity (GA ≤28 weeks) with higher-order and lower-order aberrations of the total cornea. Vertical coma was higher in extreme prematurity (P < 0.001), due to the shape of the anterior corneal surface, while there was no association with trefoil and spherical aberration. ROP was not associated with higher-order aberrations when adjusted for gestational age group. Conclusions This study demonstrated that specific corneal aberrations were associated with extreme prematurity rather than with ROP occurrence.
Ophthalmologe | 2016
A. Fieß; Stefan Dithmar; R. Kölb-Keerl; A. Kunze; M. Riße; Markus Knuf; Jacqueline Bauer
This report describes the case of a 10-month-old infant, who was delivered to our hospital by the emergency physician intubated and in an unclear unconscious state. The father reported that the child had fallen from the couch to the ground. The consulted ophthalmologist reported venous stasis in both eyes including intraretinal and preretinal bleeding in all four quadrants, a diffuse vitreous hemorrhage in the right eye and temporal retinal wrinkling in both eyes. Based on these particular clinical findings a shaken baby syndrome was suspected. This report demonstrates the importance of recognizing and correctly interpreting the typical ophthalmological signs of physical child abuse in order to detect and prevent further mistreatment of children; moreover, the increasing importance of photographic documentation and histological work-up of the findings for forensic reasons are emphasized.
Ophthalmologe | 2016
A. Fieß; Jacqueline Bauer; C. Schindel; Markus Knuf; Stefan Dithmar
BACKGROUND This case report describes an extremely rare Candida lens abscess in a premature infant (gestational age 24 weeks at birth). CASE REPORT After birth the infant suffered from Candida sepsis which was successfully treated with an antifungal medication. The patient was referred at the age of 6 months because of greyish alterations in the pupils but an absence of other symptoms. The examination with the patient under general anesthesia revealed a grey pupillary membrane and behind it a whitish swollen lens. A lensectomy was performed. The vitreous body was inconspicuous. Candida albicans was identified microbiologically. CONCLUSIONS In preterm infants dissemination of pathogens into the lens through the vascular coat of the lens is possible, which after regression of the coat is no longer accessible to systemic treatment and may thus be manifested as delayed abscess formation.
Ophthalmologe | 2016
A. Fieß; Jacqueline Bauer; C. Schindel; Markus Knuf; Stefan Dithmar
BACKGROUND This case report describes an extremely rare Candida lens abscess in a premature infant (gestational age 24 weeks at birth). CASE REPORT After birth the infant suffered from Candida sepsis which was successfully treated with an antifungal medication. The patient was referred at the age of 6 months because of greyish alterations in the pupils but an absence of other symptoms. The examination with the patient under general anesthesia revealed a grey pupillary membrane and behind it a whitish swollen lens. A lensectomy was performed. The vitreous body was inconspicuous. Candida albicans was identified microbiologically. CONCLUSIONS In preterm infants dissemination of pathogens into the lens through the vascular coat of the lens is possible, which after regression of the coat is no longer accessible to systemic treatment and may thus be manifested as delayed abscess formation.
Ophthalmologe | 2015
A. Fieß; Jacqueline Bauer; C. Schindel; Markus Knuf; Stefan Dithmar
BACKGROUND This case report describes an extremely rare Candida lens abscess in a premature infant (gestational age 24 weeks at birth). CASE REPORT After birth the infant suffered from Candida sepsis which was successfully treated with an antifungal medication. The patient was referred at the age of 6 months because of greyish alterations in the pupils but an absence of other symptoms. The examination with the patient under general anesthesia revealed a grey pupillary membrane and behind it a whitish swollen lens. A lensectomy was performed. The vitreous body was inconspicuous. Candida albicans was identified microbiologically. CONCLUSIONS In preterm infants dissemination of pathogens into the lens through the vascular coat of the lens is possible, which after regression of the coat is no longer accessible to systemic treatment and may thus be manifested as delayed abscess formation.