UDUmut Dağ

Umut Dağ

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Umut Dağ has a total of 14 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Real-world injection burden, treatment switching, and visual outcomes in diabetic macular edema: a 563-eye cohort study

    by Hasan Öncül, Umut Dağ, Hüseyin Dinç, Mehmet Fuat Alakuş

    To evaluate real-world injection burden, treatment switching patterns, and visual outcomes in patients with diabetic macular edema (DME) receiving intravit

  • Open Access

    Evaluation of primary care physicians’ knowledge, attitudes, and awareness levels regarding age-related macular degeneration

    by Hasan Öncül, Betül Dertsiz Kozan, Umut Dağ, Mehtap Çağlayan, Mehmet Fuat Alakuş, Cengiz Temel, Elif Sedanur Utlu

    Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in individuals over the age of 50. This study aims to evaluate the

  • Open Access

    The effect of strabismus surgery on the quality of life in children and adolescents

    by Betül Dertsiz Kozan, Mehtap Savar Çağlayan, Mesut Sari, Mehmet Fuat Alakuş, Hasan Öncül, Umut Dağ

    We aimed to examine the effect of strabismus surgery on quality of life levels in children and adolescents. The Health-Related Quality of Life Inventory version 4.0 (HRQOL 4.0), consisting of 23 questions and 4 subscales (physical functioning, emotional functioning, social functioning, and school problems), was administered to the children and adolescents who underwent strabismus surgery and their parents between December 2024 and June 2025, at preoperative and postoperative 1st and 3rd months. The postoperative deviation angle of the cases was 10 Prism Diopter (PD) or less. Strabismus surgery was performed by an Ophthalmologist, and the scales were evaluated by a Child and Adolescent Psychiatrist. 27 cases were included in our study. 17 (62.9%) of the cases were girls and 10 (37.1%) were boys. The average age was 9.0 ± 3.9 (7–17) . In child and adolescents, the change in the physical functionality parameters of the cases was not statistically significant (p >0.05), but the change in the parameters of emotional functionality, social functionality and school-related problems between the preoperative, postoperative 1st month and postoperative 3rd month was statistically significant (p < 0.05). In the parents’ proxy opinion of the child, the change in physical functionality, emotional functionality, social functionality parameters between preoperative, postoperative 1st month and postoperative 3rd month was statistically significant (p < 0.05), but in the parameters of school-related problems, preoperative, postoperative 1st month and postoperative 3rd month were statistically significant. The change between was not statistically significant(p >0.05) (Table 2). Successful surgery for strabismus results in measurable improvement in the quality of life in children and adolescents and in the parents proxy opinion of the child’s quality of life.


  • Open Access

    Makula Tutulumu Olmayan Regmatojen Retina Dekolmanlı Hastalarda Silikon Yağı Kullanımının Makula Tabakalarının Kalınlıkları Üzerine Etkisi

    by Umut Dağ, Mehtap Çağlayan

    Amaç: Retina dekolmanı tedavisinde göz içi tamponad olarak kullanılan silikon yağlarının makula tabakalarının kalınlıkları üzerine etkisini araştırmaktır. Yöntemler: Çalışmaya makula tutulumu olmayan Regmatojen retina dekolmanı nedeniyle opere edilen ve göz içi tamponad olarak silikon yağı kullanılan 42 hastanın 42 gözü dahil edildi. Tüm hastaların cerrahi öncesi ve silikon yağı çıkarıldıktan sonraki en iyi görme keskinliği değerleri (EİGK) ile segment analiz sistemi kullanılarak Optik Koharens Tomografi (OKT) cihazı ile otomatik olarak ölçülen merkezi makula kalınlığı (MMK), retina sinir lifi tabakası (RSLT), gangliyon hücre tabakası (GHT), iç pleksiform tabaka (İPT), iç nükleer tabaka (İNT), dış pleksiform tabaka (DPT), dış nükleer tabaka (DNT), retina pigment epitelyum tabakası (RPET), iç retina tabakası (İRT) ve dış retina tabakası (DRT) kalınlık değerleri karşılaştırıldı. Ayrıca kullanılan silikon yağının viskozitesine göre subgrup analizi yapılarak 1000 ve 5000 centistokes (cst)silikon yağı kullanılan olgulara ait veriler ayrı ayrı karşılaştırıldı. Bulgular:Silikonize gözlerde MMK, RSLT, GHT, İPT, İNT, DPT, DNT ve İRT kalınlık değerlerinde cerrahi öncesine göre anlamlı bir incelme mevcuttu (tüm değerler için p>0,05). 1000 cst grubunda İPT, İNT, DPT, DNT ve İRT kalınlık değerleri cerrahi öncesi değerlere göre anlamlı düşükken (sırasıyla; p: 0,013, p: 0,049, p: 0,023, p: 0,008 ve p

  • Open Access

    Evaluation of the Effect of Cryotherapy in Limbal Conjunctival Autograft Technique in Pterygium Surgery

    by Umut Dağ, Mehtap Çağlayan, Süleyman Vardar, Fuat Alakuş, Hasan Öncül, Yusuf Yildirim

    Aim: To compare the complication and recurrence rates in patients undergoing limbal conjunctival autograft with or without adjuvant cryotherapy for primary or recurrent pterygia.Methods: All information about the cases operated between January 2014 and January 2019 was scanned from the electronic database. Fifty-three eyes undergoing limbal conjunctival autograft combined with cryotherapy were classified as Group 1, and 47 eyes undergoing only limbal conjunctival autograft were classified as Group 2. Any development of new fibrovascular tissue from the limbus to the cornea after surgery was considered a recurrence. Any complications occurring during and after surgery were noted.Results: In Group 1, 45 of the 53 patients had primary and eight had recurrent pterygia. In Group 2, 41 of the 47 patients had primary and six had recurrent pterygia. Both groups were similar in terms of age and gender (p=0.880 and p=0.835, respectively). The mean follow-up period was 27.0±8.6 months in Group 1 and 28.7±7.8 months in Group 2 (p=0.287). No recurrences were observed during the follow-up period in Group 1, while the recurrence rate in Group 2 was 10.6% (p=0.02). All relapses occurred within the first year. No complications were observed during surgery in either group. Graft oedema was observed in the early post-operative period in four patients in Group 1 and three patients in Group 2.Conclusion: Limbal conjunctival graft technique combined with cryotherapy is a successful and reliable method in the treatment of primary and recurrent pterygium.

  • Open Access

    The effect of chalazion excision on the aberrometric and densitometric values of the cornea.

    by Hasan Oncul, Yusuf Yildirim, Mehtap Caglayan, Umut Dag, Mehmet Fuat Alakus

    The aim of this study was to investigate the effect of chalazion excision on corneal aberrations and corneal densitometry. Thirty-six patients with a chalazion in 1 eyelid and 40 healthy subjects were included in the study. Corneal aberration parameters of total root mean square (RMS), RMS high-order aberration (HOA), horizontal trefoil, oblique trefoil, horizontal coma, vertical coma, and spherical aberration values were measured using Scheimpflug corneal topography (Pentacam HR; Oculus Optikgeräte GmbH, Wetzler, Germany). Corneal densitometry values measured from 4 regions of the cornea (0-2, 2-6, 6-10, and 10-12 mm) and 4 corneal depths (anterior, central, posterior, and total) were recorded. Preoperative measurements of the patients (Group 1), postoperative first-month measurements (Group 2), and control group (Group 3) measurements were compared. The total RMS measurement was 1.64±0.48 μm in Group 1, 1.35±0.32 μm in Group 2, and 1.17±0.38 μm in Group 3 (Group 1-2: p=0.007, Group 1-3: p<0.001, Group 2-3: p=0.173). The mean spherical aberration value was 0.183±0.057 μm in Group 1, 0.157±0.048 μm in Group 2, and 0.144±0.050 μm in Group 3 (Group 1-2: p=0.104, Group 1-3: p=0.004, Group 2-3: p=0.781). The total corneal densitometric measurement was 15.95±1.80 gray scale units (GSU) in Group 1, 14.76±1.76 GSU in Group 2, and 14.33±1.49 GSU in Group 3 (Group 1-2: p=0.01, Group 1-3: p<0.001, Group 2-3: p=0.804). It was observed that some corneal aberration and corneal densitometry values were higher in patients with a chalazion compared with those of healthy individuals, and there was a decrease in corneal aberration and densitometry values after surgical excision.


  • Ocular findings in patients with coronavirus disease 2019 (COVID‐19) in an outbreak hospital

    by Hasan Öncül, Fatma Yılmaz Öncül, Mehmet Fuat Alakus, Mehtap Çağlayan, Umut Dag

    Purpose: The aim of this study was to investigate the ocular findings observed in patients with coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 and to present the relationship between ocular involvement, systemic findings, and laboratory results.Material and Methods: This cross‐sectional study was carried out between 1 May and 30 June 2020. The study included 359 patients diagnosed with COVID‐19 and assessed by clinical evaluation, nasopharyngeal polymerase chain reaction, and lung computed tomography.Results: One hundred ninety‐seven (54.9%) of the patients were male and 162 (45.1%) were female. The mean age of the patients was 58.5 years (20‐91). Two hundred ninety‐four (81.9%) patients were treated in the inpatient clinic and 65 (18.1%) patients were treated in the intensive care unit. Various ocular diseases were observed in 16 (4.5%) of the patients. Although the rate of ocular disease was 12 out of 294 (4.1%) in patients followed up in the inpatient clinic, this rate was 4 out of 65 (6.2%) in intensive care patients. There was no systemic problem in one patient, in whom conjunctival hyperemia was the first and only reason for admission to the hospital. Four patients followed up in the inpatient clinic had conjunctivitis at the time of admission, and conjunctivitis occurred in three patients during hospitalization. Subconjunctival hemorrhage occurred in five patients and vitreous hemorrhage in one patient.Conclusion: Ocular diseases are uncommon in COVID‐19 patients but may occur during the first period of the disease or during follow‐up. Ocular diseases may be the initial or only sign of COVID‐19 infection.


  • Evaluation of the subfoveal choroidal and outer retinal layer thickness in obese women

    by Hasan Öncül, Mehtap Çağlayan, Mehmet Fuat Alakus, Fatma Yılmaz Öncül, Umut Dag, Esref Arac, Kübra Metin

    Clinical relevance Obesity has become one of the most important health problems of today with its increasing prevalence. With the development of retinal imaging systems, obesity has been observed to be associated with changes in outer retinal layers and choroid in women. Background The aim of this study was to examine retinal layer parameters and their relationship with body mass index in obese women. Methods The study included 197 eyes of 197 women, of whom 44 were normal‐weight, 40 were overweight, 40 were class 1 obese, 38 were class 2 obese, and 35 were morbidly obese. The thickness of the choroid was measured manually using an enhanced‐depth imaging optical coherence tomography scanning program. Results The mean choroidal thickness values in five locations were lower than those of normal‐weight, overweight, class 1, and class 2 obese women, in morbidly obese women (p < 0.05 for all). Subfoveal outer retinal layer thickness and specific sublayer thickness of the photoreceptor layer values were significantly lower in morbidly obese women than in normal‐weight women, but there were no statistically significant differences between the groups in retinal pigment epithelium thickness and Bruch's membrane thickness (p = 0.001, p < 0.001, p = 1.00, and p = 0.101, respectively). Furthermore, there were significant negative relationships between body mass index and subfoveal choroidal thickness, subfoveal outer retinal layer thickness, and specific sublayer thickness of the photoreceptor layer values (r = −0.327, p < 0.001; r = −0.259, p < 0.001; and r = −0.281, p < 0.001, respectively). Conclusions Morbid obesity was associated with a thinner choroid, subfoveal outer retinal layer, and specific sublayer thickness of the photoreceptor layer in women. Furthermore, retinal hypoxia associated with morbid obesity may be related to a decrease in photoreceptor layer thickness. Thinning of the outer retinal layer may also lead to atrophy of the cone sheath.