Semra Akkaya Turhan

Dr. Semra Akkaya Turhan

Marmara University School of Medicine
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

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1 April 2020 in Journal of Refractive Surgery
Verified
Journal Article
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STSemra Akkaya Turhan
Semra Akkaya Turhan
BYBerru Yargi
Berru Yargi
ETEbru Toker
Ebru Toker
PURPOSE: To compare the efficacy and safety of accelerated corneal cross-linking (CXL) with conventional CXL in pediatric patients with keratoconus. METHODS: Consecutive patients with keratoconus received either accelerated CXL (9 mW/cm 2 irradiance for 10 minutes) or conventional CXL (3 mW/cm 2 irradiance) for 30 minutes. Visual acuities (uncorrected [UDVA] and corrected [CDVA] distance visual acuity, logMAR), spherical error, cylindrical error, spherical equivalent, and keratometric values were recorded. Follow-up measurements were compared with baseline values. RESULTS: The study enrolled 48 eyes: 22 eyes had accelerated CXL (mean age: 16.0 ± 1.7 years) and 26 eyes had conventional CXL (mean age: 15.7 ± 1.6 years). Compared with preoperative values, all mean keratometric values significantly improved in the accelerated CXL group (flat [K1]: Δ = −0.64 D, P < .0001, steep [K2]: Δ = −0.63 D, P = .009 and Kmax: Δ = −0.55 D, P = .028), but no significant changes were observed in the mean UDVA and CDVA. In the conventional CXL group, all mean keratometric values and CDVA significantly improved (K1: Δ = −0.65 D, P = .017, K2: Δ = −0.87 D, P = .006, Kmax: Δ = −1.47 D, P = .011). No significant changes were observed in refractive error in either CXL group. There were no significant differences in the keratometric readings, visual acuities, or refractive error between the two groups at the 2-year follow-up. CONCLUSIONS: Both conventional and accelerated CXL protocols appear to be effective in stabilizing keratoconus progression in pediatric patients. Improved CDVA was also observed in the conventional CXL group. Accelerated CXL, with its advantage of shorter treatment duration, may be an alternative in pediatric patients. [ J Refract Surg . 2020;36(4):265–269.]

28 November 2022 in Eye
Verified
Journal Article
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SGSamet Gulkas
Samet Gulkas
FAFahri Onur Aydin
Fahri Onur Aydin
STSemra Akkaya Turhan
Semra Akkaya Turhan
ATAyse Ebru Toker
Ayse Ebru Toker
Purpose To investigate small nerve fibre damage and inflammation at the level of the sub-basal nerve plexus (SNP) of severe obese patients and compare the results with those of healthy subjects. Methods This cross-sectional, observational study investigated the data of 28 patients (14 out of 28 prediabetic or diabetic) with severe obesity (Body Mass Index; BMI ≥ 40) and 20 healthy subjects. Corneal nerve fibre density (CNFD), branch density (CNBD), fibre length (CNFL), nerve fibre area (CNFA), nerve fibre width (CNFW), and nerve fractal dimension (CNFrD) and dendritic cell (DC) density were evaluated using in vivo confocal microscopy (IVCM, Heidelberg Retinal Tomograph III Rostock Cornea Module). Automatic CCMetrics software (University of Manchester, UK) was used for quantitative analysis of SNP. Results Mean age was 48.4±7.4 and 45.1 ± 5.8 in the control and obese group, respectively (p = 0.09). Mean BMI were 49.1 ± 7.8 vs. 23.3 ± 1.4 in obese vs. control group, respectively (p < 0.001). Mean CNFD, CNBD, CNFL, CNFA, CNFW were significantly reduced in obese group compared with those in the control group (always p < 0.05, respectively). There were no significant differences in any ACCMetrics parameters between prediabetic/diabetic and non-diabetic obese patients. Increased DC densities were detected in obese group compared with those in control group (p < 0.0001). There were significant correlations between BMI scores and SNP parameters. Conclusion Imaging with IVCM is a feasible, non-invasive method to detect and quantify occult corneal nerve damage and increased inflammation in patients with obesity. This study suggests that obesity may be a separate risk factor for peripheral neuropathy regardless of DM.



29 December 2020 in Turkish Journal of Ophthalmology
Verified
Journal Article
Open access
STSemra Akkaya Turhan
Semra Akkaya Turhan
DÖDeniz Özarslan Özcan
Deniz Özarslan Özcan
ETEbru Toker
Ebru Toker
To assess the visual performance of a mini-scleral lens in patients with keratoconus and to evaluate its fit by optical coherence tomography (OCT). Twenty-nine eyes of 24 patients with keratoconus were fitted with a mini-scleral lens (Esclera; Mediphacos Inc., Belo Horizonte, Brazil). Diagnostic lenses were used in the initial fitting process. The lens fit was evaluated by the fluorescein pattern and also by anterior segment OCT (RTVue, Optovue Inc., Fremont, CA). Within 30-45 minutes after insertion, the lens fit parameters including central corneal and limbal clearance, and peripheral landing zone alignment were evaluated by OCT. High- and low-contrast visual acuity (VA), subjective performance for comfort and vision (5-point Likert scale), and overall satisfaction with the lens (100 mm visual analog scale [VAS]) were measured before and after lens wear. The mean decimal high-contrast VA (best spectacle-corrected VA: 0.40±0.14 vs VA with the scleral lens: 0.93±0.12, p<0.0001) and low-contrast VA (best spectacle-corrected VA: 0.60±0.24 vs VA with the scleral lens: 1.15±0.18, p<0.0001) significantly improved with lens wear. The mean central corneal clearance was 120.7±24.5 μm. There were no correlations between the keratometric values and the sagittal depth of the scleral lens. The mean number of trial lenses required for ideal fit was 2.2 lenses (range: 1-8). Patients reported high scores for comfort (mean score: 4.69; range: 4-5), vision (mean score: 4.62; range: 3-5) and overall satisfaction with the lens (mean VAS score: 88.1; range: 70-100). The mini-scleral lens provided good high- and low-contrast visual acuity and high patient satisfaction in patients with keratoconus. Anterior segment OCT imaging facilitated the evaluation of the fit.

24 November 2020 in Journal of Clinical Medicine
Verified
Journal Article
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Gysbert van SettenGysbert van Setten
Gysbert van Setten
OSOliver Stachs
Oliver Stachs
BDbenedicte dupas
benedicte dupas
STSemra Akkaya Turhan
Semra Akkaya Turhan
Berthold SeitzBerthold Seitz
Berthold Seitz
Wolfgang Müller-LierheimWolfgang Müller-Lierheim
Wolfgang Müller-Lierheim
The purpose of this study was to investigate the effect of high molecular weight hyaluronan (HMWHA) eye drops on subbasal corneal nerves in patients suffering from severe dry eye disease (DED) and to evaluate the damage of subbasal corneal nerves associated with severe DED. Designed as an international, multicenter study, 16 patients with symptoms of at least an Ocular Surface Disease Index (OSDI) score of 33, and corneal fluorescein staining (CFS) of at least Oxford grade 3, were included and randomized into two study arms. The control group continued to use their individual optimum artificial tears over the study period of eight weeks; in the verum group, the artificial tears were substituted by eye drops containing 0.15% HMWHA. At the baseline visit, and after eight weeks, the subbasal nerve plexus of 16 patients were assessed by confocal laser scanning microscopy (CSLM). The images were submitted to a masked reading center for evaluation. Results showed a significant increase of total nerve fiber lengths (CNFL) in the HMWHA group (p = 0.030) when compared to the control group, where the total subbasal CNFL did not significantly change from baseline to week 8. We concluded that in severe DED patients, HMWHA from topically applied eye drops could cross the epithelial barrier and reach the subbasal nerve plexus, where it exercised a trophic effect.