Oliver Niels Klefter

Dr. Oliver Niels Klefter


Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 March 2023 in Acta Ophthalmologica
Verified
Journal Article
Closed access
IPIvan Potapenko
Ivan Potapenko
LBLars Christian Boberg‐Ans
Lars Christian Boberg‐Ans
MHMichael Stormly Hansen
Michael Stormly Hansen
OKOliver Niels Klefter
Oliver Niels Klefter
EDElon H.C. van Dijk
Elon H.C. van Dijk
Yousif SubhiYousif Subhi
Yousif Subhi

28 February 2024 in Graefe's Archive for Clinical and Experimental Ophthalmology
Verified
Journal Article
Open access
PDF file
MSMiklos Schneider
Miklos Schneider
JBJakob Bjerager
Jakob Bjerager
DHDelila Hodzic-Hadzibegovic
Delila Hodzic-Hadzibegovic
OKOliver Niels Klefter
Oliver Niels Klefter
Yousif SubhiYousif Subhi
Yousif Subhi
JHJavad Nouri Hajari
Javad Nouri Hajari
Purpose: To report short-term outcomes of treatment switch to faricimab in real-world patients with aflibercept-resistant neovascular age-related macular degeneration (AMD). Methods: Single-center, retrospective cohort study with chart-review using electronic injection database, electronic medical records, and optical coherence tomography (OCT) data from May to September 2023. Results: A total of 50 eyes of 46 patients were analyzed. Faricimab treatment led to absence of fluid in 32% of the eyes and a reduction of fluid in 84% of the eyes. There was a statistically significant decrease in central retinal thickness (CRT) and pigment epithelial detachment (PED) height in those that responded to the switch (median difference: − 31 μm, IQR: 55, p < 0.0001 and median difference: − 21 μm, IQR: 36, p < 0.0001, respectively) and a statistically significant increase in CRT (median difference: + 19 μm, IQR: 20, p = 0.0143) and no change in PED height (median difference: + 22 μm, IQR: 64, p = 0.1508) in those that did not. Best-corrected visual acuity (BCVA) showed marginal decrease with low statistical significance. No ocular or systemic safety events were observed. Conclusions: Our findings suggest that switching to faricimab is generally safe and effective in patients with neovascular AMD who are otherwise difficult to treat and have residual fluid despite frequent injections with aflibercept. We observed a high rate of morphological response to the treatment switch, improvement of anatomical parameters with about one-third of patients having dry macula following a single injection, and a marginal change in BCVA. Sustainability of these results requires further investigation. Study registration: ClinicalTrials.gov registration number: NCT06124677. Date of registration: 09/11/2023, retrospectively registered.

1 September 2013 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Closed access
MKM. Klose
M. Klose
DMD. Marina
D. Marina
MHM.-L. Hartoft-Nielsen
M.-L. Hartoft-Nielsen
OKOliver Niels Klefter
Oliver Niels Klefter
VGV. Gavan
V. Gavan
UFU. Feldt-Rasmussen
U. Feldt-Rasmussen
Context: Thyroid dysfunction may have detrimental effects on patient outcomes. Few studies have assessed this issue in patients with secondary hypothyroidism.Objective: Our objective was to test the hypothesis that thyroid hormone status has an impact on cardiovascular risk factors in adult patients with hypopituitarism.Design and Setting: This was a retrospective observational study (1993–2012) at a tertiary referral university hospital.Patients: All GH-deficient patients starting GH replacement (1993–2009) with measured free T4 (fT4) (n = 208). Baseline fT4 defined patients as TSH-sufficient and TSH-deficient (further divided into tertiles according to baseline fT4; first tertile had lowest fT4).Main Outcome Measures: Anthropometric (body mass index [BMI], waist circumference, total fat (fat mass) and lean body mass [LBM]) and biochemical (lipids and fasting plasma glucose) data were collected at baseline and a median 4.1 years after commencement of GH.Results: At baseline, fT4 was negatively associated with BMI and waist circumference, but positively with high-density lipoprotein, independent of age, gender, and IGF-I (SD score). Only first-tertile TSH-deficient patients had higher BMI (P = .02), fat mass (P = .03), total cholesterol (P = .05), triglycerides (P < .01), and waist circumference (P = .01), and lower high-density lipoprotein cholesterol (P = .03) as compared with TSH-sufficient patients. At follow-up, IGF-I, LBM, and plasma glucose had increased in all subgroups (P < .01). The change in fT4 (ΔfT4) (follow-up − baseline) was negatively correlated to ΔBMI, ΔLBM, Δtotal cholesterol, and Δlow-density lipoprotein cholesterol (all P < .05, adjusted for ΔIGF-I and ΔGH and hydrocortisone dose). The negative correlation to Δtotal cholesterol and Δlow-density lipoprotein cholesterol persisted only in first-tertile TSH-deficient patients.Conclusion: This single-center study over a 20-year period has strengthened the importance of improved awareness of thyroid status and optimal thyroid replacement of hypopituitary patients to reduce cardiovascular risks in hypopituitary patients.

21 December 2024 in Journal of Personalized Medicine
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Journal Article
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Mehmet Cem SabanerMehmet Cem Sabaner
Mehmet Cem Sabaner
RARodrigo Anguita
Rodrigo Anguita
FAFares Antaki
Fares Antaki
Michael BalasMichael Balas
Michael Balas
LBlars Christian Boberg-Ans
lars Christian Boberg-Ans
Yousif SubhiYousif Subhi
Yousif Subhi
Artificial intelligence (AI) is becoming increasingly influential in ophthalmology, particularly through advancements in machine learning, deep learning, robotics, neural networks, and natural language processing (NLP). Among these, NLP-based chatbots are the most readily accessible and are driven by AI-based large language models (LLMs). These chatbots have facilitated new research avenues and have gained traction in both clinical and surgical applications in ophthalmology. They are also increasingly being utilized in studies on ophthalmology-related exams, particularly those containing multiple-choice questions (MCQs). This narrative review evaluates both the opportunities and the challenges of integrating chatbots into ophthalmology research, with separate assessments of studies involving open- and close-ended questions. While chatbots have demonstrated sufficient accuracy in handling MCQ-based studies, supporting their use in education, additional exam security measures are necessary. The research on open-ended question responses suggests that AI-based LLM chatbots could be applied across nearly all areas of ophthalmology. They have shown promise for addressing patient inquiries, offering medical advice, patient education, supporting triage, facilitating diagnosis and differential diagnosis, and aiding in surgical planning. However, the ethical implications, confidentiality concerns, physician liability, and issues surrounding patient privacy remain pressing challenges. Although AI has demonstrated significant promise in clinical patient care, it is currently most effective as a supportive tool rather than as a replacement for human physicians.

29 January 2022 in Eye
Verified
Journal Article
Closed access
PDF file
MHMichael Stormly Hansen
Michael Stormly Hansen
LTLene Terslev
Lene Terslev
MJMads Radmer Jensen
Mads Radmer Jensen
JBJane Maestri Brittain
Jane Maestri Brittain
UDUffe Møller Døhn
Uffe Møller Døhn
Steffen HamannSteffen Hamann
Steffen Hamann

29 September 2016 in Acta Ophthalmologica
Verified
Journal Article
Open access
PDF file
AWAnne Willerslev
Anne Willerslev
MHMathias M. Hansen
Mathias M. Hansen
OKOliver Niels Klefter
Oliver Niels Klefter
OBOle Weis Bjerrum
Ole Weis Bjerrum
Hans HasselbalchHans Hasselbalch
Hans Hasselbalch
IMInger Christine Munch
Inger Christine Munch
Purpose: To study the circulation in the retinal vessels in patients with blood dyscrasia due to myeloproliferative neoplasms using non‐invasive retinal imaging.Methods: Prospective consecutive case series of seven treatment‐naïve patients with chronic myeloid leukaemia (n = 2), polycythemia vera (n = 4), essential thrombocytosis (n = 1) examined before and after cytoreductive treatment. We investigated retinal circulation with motion‐contrast imaging, retinal oximetry and spectral‐domain optical coherence tomography.Results: Retinal venous blood velocity increased by 8.14% (CI95 3.67% to 12.6%, p = 0.004) and retinal arterial oxygen saturation increased by 7.23% (CI95 2.9% to 11.6%, p = 0.010) at follow‐up (mean 12 weeks, range 5–14 weeks) where complete haematological remission had been achieved by cytoreductive treatment. Abnormal optical coherence tomography reflectivity patterns were present at baseline in patients with chronic myeloid leukaemia and were replaced by normal patterns at follow‐up. Retinopathy, in the form of cotton‐wool spots and retinal haemorrhages, was found at presentation in the two patients with chronic myeloid leukaemia and in one patient with polycythemia vera. The retinopathy had resolved at follow‐up in all patients.Conclusion: With non‐invasive retinal imaging, we were able to demonstrate increased retinal venous blood velocity, increased retinal arterial blood oxygenation and normalization of intravascular reflectivity patterns after successful treatment of myeloproliferative neoplasms. Larger prospective studies are needed to assess the prognostic value of these non‐invasive imaging methods in predicting circulatory complications in myeloproliferative neoplasms.