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To assess choroidal structural changes in diabetic patients in association with disease duration, HbA1c level, and presence of retinopathy.This retrospective cross-sectional study included treatment-naive patients with non-proliferative DR (NPDR) (group 1), diabetic patients without DR (group 2), and healthy subjects (group 3). Patients were also grouped according to the duration of diabetes: long-term group ( 15 years, n = 32) and short-term group (˂ 15 years, n = 28). The choroidal thickness was measured at three points; subfoveal, 1500 μm nasal, and 1500 μm temporal to the fovea. The choroidal area, stromal area, luminal area (LA), and choroidal vascularity index (CVI) were quantified using ImageJ. Partial correlation analysis and one-way analysis of covariance test were performed for statistical analysis.The study included 30 eyes of 30 treatment-naive patients with NPDR (group 1), 30 eyes of 30 diabetic patients without DR (group 2), and 30 eyes of 30 healthy persons (group 3). The mean subfoveal, nasal, and temporal choroidal thicknesses were decreased in group 1 in comparison with controls (p 0.001, p = 0.035, and p = 0.005, respectively). The mean LA in group 1 and group 2 were both significantly lower compared to group 3 (group 1 vs. group 3, p = 0.004; group 2 vs. group 3, p = 0.020). CVI was significantly lower in group 1 and group 2 than in controls (group 1 vs. group 3, p = 0.019; group 2 vs. group 3, p = 0.025). CVI was significantly lower in the long-duration group than in the short-duration group (p 0.001). A moderate negative correlation was found between the duration of diabetes and CVI (r = - 0.467, p 0.001). A moderate negative correlation was found between HbA1c level and luminal area and CVI (r = - 0.466, p 0.001, and r = - 0.425, p 0.001, respectively).Choroidal structure and CVI are altered even in the absence of clinically confirmed retinopathy and these alterations are related to the duration of diabetes.

BACKGROUND There is growing evidence supporting an association between obstructive sleep apnea syndrome (OSAS) and systemic vascular disorders. However, the data on choroidal microvasculature are limited. In recent years, choroidal thickness (CT) and choroidal vascularity index (CVI) have been of considerable interest as objective markers of choroidal vascularity. We hypothesized that the imbalance of vascular regulation in OSAS may adversely affect the CT and CVI and may help to assess the vascular risk in these patients. PURPOSE This study aimed to evaluate the choroidal morphology in patients with OSAS. MATERIALS AND METHODS Patients with moderate OSAS were included to this study. The subfoveal, nasal, and temporal CT were calculated. The choroidal area (CA) was binarized to the luminal area (LA) and stromal area (SA) using ImageJ software. The CVI was calculated as the proportion of the LA to the total CA. RESULTS Of 40 eyes of 40 patients, the mean subfoveal CT was significantly decreased in the OSAS group in comparison to the controls (p = 0.032). The mean CA, LA, and SA were decreased in the OSAS group compared with the controls, but the differences did not reach a statistical significance (p = 0.132, p = 0.104, and p = 0.184, respectively). The CVI was not significantly changed in patients with OSAS (p = 1.000). CONCLUSION Unlike CT, there were no significant differences in choroidal structural parameters and CVI in patients with OSAS.

Objectives To identify microbiological growth on bicanalicular silicone tubes (BST) placed during dacryocystorhinostomy (DCR) surgery and to analyze the association between culture results and surgical outcomes and BST removal time. Materials and methods A total of 80 lacrimal drainage systems of 68 patients who had external DCR with bicanalicular silicone intubation were included the study. Twenty-five tubes (31.3%) were removed up to 8 weeks, 28 tubes (35.0%) were removed between 9 and 11 weeks, and the remaining 27 tubes (33.7%) were removed 12 weeks or more after surgery. The tubes were transferred to Stuart medium and sent for microbiologic examination. The disc diffusion method was used to determine antibiotic resistance. Results Culture positivity was observed for 96.2% of the tubes. Among a total of 109 isolates, 63 were gram-positive bacteria (57.8%), 37 were gram-negative bacteria (34%), and 9 were fungi (8.2%). The most commonly isolated gram-positive and gram-negative bacteria were Staphylococcus aureus (66.6%) and Enterobacter spp. (29.7%), respectively. Penicillin, clindamycin, erythromycin, and tetracycline resistances were higher among gram-positive pathogens. Cephalothin, amoxicillin-clavulanic acid, and ampicillin resistances were higher among gram-negative pathogens. There was no significant difference in terms of the microbiological profile between the three groups of removed tubes. Haemophilus influenzae was isolated at a significantly higher rate in patients with surgical failure (p=0.04). Conclusion Although a variety of agents were isolated from removed BST, gram-positive organisms were more frequent than gram-negatives and fungi. S. aureus and Enterobacter were the most common gram-positive and gram-negative isolates. Later BST removal was associated with the isolation of significantly more bacterial strains per tube. There was no correlation between multiple infections and surgical failure. H. influenzae was more common in failed DCR cases.

Purpose To define the choroidal morphological characteristics of non-exudative age-related macular degeneration (AMD) cases associated with acquired vitelliform lesions (AVLs). Methods This retrospective study included intermediate AMD patients with AVLs (Group1, 21eyes) and without AVLs (Group2, 21eyes). A healthy control group was (Group3, 23eyes) also included. Subfoveal choroidal thickness (SFCT), greatest basal diameter (GBD), and maximum height (MH) of the largest PED were measured on spectral domain optical coherence tomography. Internal reflectivity of PEDs and total choroidal area (TCA) were measured using ImageJ software. The TCA was binarized to the luminal area (LA) and stromal area. The choroidal vascularity index (CVI) was assessed. Results The mean SFCT, TCA, and LA were higher in Group 1 (290.3 ± 86.8 μm, 0.840 ± 0.302 mm2, 0.602 ± 0.227 mm2) than in Group 2 (215.6 ± 85.0 μm, 0.594 ± 0.183 mm2, 0.429 ± 0.139 mm2) ( p = 0.014, p = 0.017, p = 0.020, respectively). There was no significant difference in the CVI measurements between Group 1 and Group 2 (p = 1.000). The mean GBD and MH of the PED was higher in Group 1 (1443 ± 595 µm, 188 ± 86 µm) than in Group 2 (851 ± 368 µm, 119 ± 38 µm) ( p = Conclusion Non-exudative AMD patients with AVLs are more prone to have a thick choroid and large hyporeflective PEDs as compared to the those without AVLs.

A 63-year-old Caucasian man with metastatic lung adenocarcinoma undergoing chemotherapy and external radiotherapy was referred for routine eye examination. Although he was asymptomatic, ocular examination revealed a relatively well-circumscribed whitish retinal lesion measuring0.5×0.5×0.5 mm located along the inferotemporal vascular arcade in the right eye. Optical coherence tomography (OCT) showed a hyperreflective dome-shaped lesion occupying the inner retinal layers with few hyperreflective dots overlying the retina in the posterior vitreous consistent with tumor cells. Fluorescein angiography revealed early hyperfluorescence and late staining without leakage at the lesion site. A diagnosis of presumed retinal metastasis from lung adenocarcinoma was made. At 2 months follow-up after completion of chemotherapy, the retinal lesion was found to have regressed completely leaving minor irregularities in the inner retinal layers on OCT. To date, there have been only 41 cases of carcinoma metastasis to the retina reported in the literature including the current case. Despite its rarity, retinal metastasis should be considered in the differential diagnosis of a white-yellow retinal mass with/without overlying vitreous cells especially in patients with a history of systemic cancer.

Purpose To evaluate morphological and functional state of the meibomian glands (MG) in keratoconus patients. Methods One hundred eyes of 100 keratoconus patients and 100 eyes of 100 age-matched control subjects were included into this study. Ocular Surface Disease Index (OSDI) scores, non-invasive break up time (NIBUT), findings of meibography, staining with fluorescein of the ocular surface, tear film break-up time (TBUT), and Schirmer I test were documented in all patients’ eyes and control eyes and were compared between the groups . Results The mean TBUT and NIBUT were significantly lower, corneal staining and OSDI scores were statistically greater in the keratoconus group (p Conclusion Our data suggests that corneal ectasia in keratoconus is related with alterations in ocular surface, tear film function and MG morphology. Early screening and treatment of MG dysfunction may improve ocular surface quality and allow better disease management in keratoconus patients.

To determine the cut-off levels for choroidal thickness and choroidal vascularity index (CVI) to differentiate among pachychoroid spectrum diseases.A retrospective comparative study METHODS: A total of 143 eyes were included. Of these 29 had uncomplicated pachychoroid (UCP), 29 had pachychoroid pigment epitheliopathy (PPE), 25 had pachychoroid neovasculopathy (PNV), 30 had central serous chorioretinopathy (CSC), and 30 had polypoidal choroidal vasculopathy (PCV). The choroidal areas were measured with ImageJ software. The CVI, the proportion of the luminal area to the total choroidal area, was assessed.The cut-off points of central choroidal thickness were determined as 360 µm for the PPE and PCV group pair (p 0.001), 422 µm for the PNV and CSC group pair (p = 0.026), 271 µm for the PNV and PCV group pair (p 0.001), and 341 µm for the CSC and PCV group pair (p 0.001). The cut-off points of CVI were 72.7 for the PPE and PCV group pair (p 0.001), 74.7 for the PNV and CSC group pair (p = 0.005), 72.6 for the PNV and PCV group pair (p = 0.001), and 73.6 for the CSC and PCV group pair (p 0.001).Pachychoroid spectrum may be composed of a combination of distinct choroidal diseases with different vascular and structural characteristics.

Purpose: To evaluate choroidal vascularity index (CVI) after a single dose of intravitreal dexamethasone implant in refractory diabetic macular oedema (DME). Methods: Total choroidal area, luminal area, and CVI were measured at baseline, 1st month, and at 3rd month after dexamethasone implant using binarization of enhanced depth imaging optical coherence tomography (EDI-OCT) images. Results: A total of 25 eyes of 25 patients (mean age: 61.4 ± 8.3 years; 12 males, 13 females), were enroled in the study. All eyes had been previously treated with intravitreal aflibercept injections (mean number of injections 4.6 ± 2.5). Mean CVI was 70.3 ± 8.1 prior to intravitreal dexamethasone treatment. It was decreased to 66.1 ± 9.3 at 1 month and 63.5 ± 10.1 at 3 months after treatment. The mean CVI was significantly decreased at 3 months compared with pre-treatment measures (p = 0.033). Conclusion: CVI was found to be decreased in patients who responded to intravitreal dexamethasone implant. © 2022 Elsevier B.V.

Objectives: To report treatment results and complications of stereotactic radiosurgery in uveal malignant melanoma and to identify risk factors for development of radiation retinopathy. Materials and Methods: This was a retrospective study of 36 patients diagnosed with uveal melanoma between 2014 and 2019. Best corrected visual acuity, funduscopic findings, basal tumor diameter and tumor thickness were recorded at baseline and at follow-up visits at 3-month intervals. The response of tumors to stereotactic radiosurgery and complications were determined. Results: The mean basal diameter of tumor was 10.2 (range: 4.0-19.4, standard deviation [SD]: ±3.3) mm x 9.7 (range: 4.5-18.0, SD: ±3.3), tumor thickness was 5.1 (range: 2.0-11.0, ±2.4) mm at baseline. The mean follow-up period was 17.2 (range: 6-48, SD: ±10.43) months. The mean visual acuity was 0.5 (SD: ±0.3) logMAR before treatment and 0.6 (SD: ±0.3) logMAR after the mean follow-up period. The most common complications after stereotactic radiosurgery were cataract (38.9%) and radiation retinopathy (27.7%). There was a statistically significant relation between radiation retinopathy development and tumor distance from the optic disc (p=0.04). The rate of eye salvage was 83.3% in this study. Conclusion: Our short-term results show stereotactic radiosurgery was an effective and sustained treatment modality among the other eye conservation therapies.

To evaluate the choroidal vascularity index (CVI) in the fellow eyes of patients with pachychoroid neovasculopathy (PCN) and central serous chorioretinopathy (CSC). Fifty-eight asymptomatic fellow eyes from 58 patients diagnosed with PCN or CSC and 26 eyes from 26 healthy participants were included. The total choroidal area (CA), luminal area (LA), and stromal area (SA) were measured with ImageJ software and Niblack threshold method. The CVI, which was the proportion of the LA to the CA, was assessed. The CA, LA, and SA were widest in the fellow eyes of the CSC group. The differences between the fellow eyes of the CSC group and the control group and the differences between the fellow eyes of the PCN group and the CSC group were significant (p < 0.001). The CVI of the fellow eyes of the CSC group was significantly higher than the control group (74.93 ± 3.58 vs. 73.38 ± 3.09, p = 0.023). The differences in the CA, LA, and SA in particular pachychoroid diseases were evident in the asymptomatic fellow eyes. Pachychoroid diseases are characterized by thick choroid or vessels as a common feature, but they may have different structural choroidal features, which might result in different consequences.

Background: Myopia is not only refractive error, but also an eyesight-threatening disease. To search for a relationship between the central corneal thickness (CCT) and ganglion cell complex (GCC) thickness in patient with myopia.Methods: The prospective cross-sectional study comprised 122 eyes of 122 subjects with mild to moderate myopia. The participants were divided into two groups according to the CCT; thicker than 555 micrometer (Group 1) or thinner than 555 micrometer (Group 2). CCT was measured using the optical biometer machine. All subjects received a slit-lamp examination and optical coherence tomography. The retinal nerve fiber layer (RNFL) thickness and GCC thickness were automatically quantified.Results: The retinal GCC and GC-IPL thickness were decreased in Group 1 compared with Group 2 (p=0.002 and p=0.007, respectively). The RNFL thickness was statistically significantly decreased only in the superior-temporal quadrant (p=0.041). There was a significantly positive correlation between CCT and GCC and GC-IPL thickness (r=0.222, p=0.014, and r=0.203, p=0.025, respectively). There was no correlation among CCT and RNFL thickness (p˃0.05).Conclusion: There was a relationship between the CCT and GCC thickness in eyes with mild to moderate myopia.

Dear Editor, We thank Marino et al. for their kind interest in our study [1]. In their letter to the editor, the authors pointed out that measurement of choroidal vascularity index (CVI) did not reveal any signifcant change and proposed that it can be due to the so-called blooming efect in the OCT imaging.

Purpose: To evaluate the choroidal structural parameters, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic density index (ODI) and their correlations in patients with migraine. Methods: Twenty-eight newly diagnosed migraine patients and 28 age-matched healthy controls were included in this prospective cross-sectional study. The enhanced depth-optical coherence tomography images were evaluated. The choroidal area (CA) was binarized to the luminal area (LA) and stromal area (SA) using Image J. The choroidal vascularity index (CVI), the mean peripapillary RNFL thickness, superior-inferior-nasal-temporal quadrant RNFL thicknesses, and the ODI were compared statistically. Results: The difference in the mean CVI between the patient group and controls reached a statistical significance (p=0.035). The mean RNFL thickness was significantly decreased in patients with migraine compared with the controls (p=0.040). The mean RNFL thickness in the superior, temporal, and inferior quadrants was significantly decreased in the patient group in comparison to the control subjects (p=0.030, p=0.001, and p=0.022, respectively). There were no significant differences between the migraine group and the controls for the mean ODI of RNFL (p=0.399). Conclusion: The CVI and the RNFL thickness except for the nasal quadrant were significantly decreased in newly diagnosed migraine patients. © 2021 Elsevier B.V.

Background: To assess the vascularity of choriocapillaris and structural choroidal differences in eyes with reticular pseudodrusen (RPD) and soft drusen. Methods: 21 eyes with RPD (group 1), 17 eyes with soft drusen (group 2), and 19 eyes as a control group (group 3) were included in this study. Choriocapillaris vascular density and flow area were measured by optical coherence tomography angiography. Total choroidal area, luminal area, stromal area, and lumen/stroma ratios were measured on optical coherence tomography B-scans converted to binary images. Results: Mean choriocapillaris vascular density was higher in group 3 than other groups (group 1 vs 3, p = 0.001; group 2 vs 3, p = 0.003). Mean flow area in choriocapillaris was higher in group 3 than other groups (group 1 vs 3, p = 0.001; group 2 vs 3, p = 0.001). Mean luminal, stromal, and total choroidal areas decreased in group 1 and group 2 compared to controls (p < 0.001, p < 0.001, and p < 0.001, respectively). The stroma ratio decreased in group 1 compared to group 3 (p = 0.013). The lumen ratio and lumen/stroma ratio increased in group 1 compared to group 3 (p = 0.012 and p = 0.008, respectively). Conclusions: The choroid of eyes with RPD and soft drusen was affected in both choriocapillaris and whole choroid layer. © 2021 Elsevier B.V.

Background: To evaluate the choroidal structural changes in multiple sclerosis (MS) patients without previous optic neuritis (ON) attacks. Methods: Forty eyes of 20 MS patients without a history of ON and 40 eyes of 20 age-matched healthy volunteers were included in this study. The choroidal thickness (CT) was measured at three points; subfoveal, 1500 µm nasal to the fovea, and 1500 µm temporal to the fovea. Choroidal area (CA), luminal area (LA), and choroidal vascularity index (CVI) were calculated using ImageJ. Results: The mean subfoveal, nasal and temporal CT were decreased in MS patients compared to controls (for all, p < 0.001). The mean LA was 0.572 ± 0.113 mm2 in MS group, and 0.729 ± 0.188 mm2 in controls (p = 0.002). The mean CVI was decreased in the MS group (69.38% ± 4.87) in comparison to the controls (73.41% ± 5.18) (p = 0.034). Conclusion: The current study demonstrated significant anatomical alterations of the choroid in the eyes of patients with MS. © 2022

We report a case of unilateral varicella-zoster virus (VZV) related keratouveitis and papillitis. A 54-year-old male presented with headache, left forehead rash, and decreased vision in the left eye. Examination of the left eye showed visual acuity (VA) of 0.15, relative afferent pupillary defect, anterior stromal corneal edema, nongranulomatous keratic precipitates, a swollen and hyperemic optic disc. The patient could read 6/12 of the Ishihara plates in the left eye. Optical coherence tomography (OCT) showed optic disc edema and OCT angiography (OCTA) revealed increased peripapillary vascularity. Computerized visual field testing demonstrated an enlarged blind spot and lower altitudinal defect. Serum anti-VZV IgM antibody level was elevated. The patient was put on oral acyclovir and prednisone treatment. At 1-month follow-up visit, VA increased to 0.9 and color vision was 11/12 Ishihara plates. OCT showed resolution of optic disc edema and OCTA demonstrated normalization of the increased peripapillary vascularity. Computerized visual field test demonstrated improvement in the lower altitudinal visual field defect and normalization of the enlarged blind spot. Optic nerve involvement in VZV infection occurs rarely, especially in immunocompetent patients as in our case.

Purpose: To evaluate the morphology and function of the meibomian glands (MG) in keratoconus patients.Methods: One hundred eyes of 100 keratoconus patients and 100 eyes of 100 age-matched healthy subjects were included into this study. Ocular Surface Disease Index (OSDI) scores, non-invasive break up time (NIBUT), meibography findings, fluorescein staining of the ocular surface, tear film break-up time (TBUT), and Schirmer I test were recorded in all patient eyes and were compared with controls.Results: The mean TBUT and NIBUT were significantly lower, corneal staining and OSDI scores were statistically higher in the keratoconus group (pConclusion: Our data suggest that corneal ectasia in keratoconus is associated with alterations in ocular surface, tear film function and MG morphology. Early screening and treatment of MG dysfunction may improve ocular surface quality and allow better disease management in keratoconus patients.

Purpose: To report a case of Candida albicans endogenous endophthalmitis in an immunocompetent patient with onychomycosis.Methods: Retrospective case report.Results: A 40-year-old man with onychomycosis presented with C. albicans subretinal abscess in the left eye. Systemic and intravitreal injections did not prevent further progression of the infection. The patient underwent pars plana vitrectomy. One month after surgery, the intraocular inflammation gradually subsided. However, his visual acuity stayed at counting fingers as a result of macular scarring.Conclusion: The aim of this case presentation is to emphasize that endogenous fungal endophthalmitis can be seen in an immunocompetent patient. The use of systemic steroids in the past was the main reason for the progression of the disease in this case. In these situations, when the clinical findings suggest a fungal etiology, it should keep in mind that endogenous candida endophthalmitis can be a result of fungal infections from distant sites such as the toenails and systemic steroids should not be started before definite diagnosis.

Purpose: To assess risk factors for progression following corneal collagen crosslinking (CXL) in eyes with keratoconus. Methods: Charts of patients who developed progression following conventional CXL treatment (Dresden protocol) were retrospectively evaluated in two centers (Center 1, and Center 2). 871 eyes of a total of 676 patients were analyzed. Progression was defined as >1 diopter (D) increase in maximum keratometry (Kmax) readings compared to baseline. Results: Progression was noted in 20 eyes of 20 patients (progression rate 3%). The mean age of the patients was 17.65 ± 5.76 (11–34) years and the mean follow-up following CXL was 36.70 ± 25.72 (12–84) months. The gender distribution was 13 (65%) females, and seven (35%) males. Four eyes (20%) had mild, 13 eyes (65%) had moderate, and three eyes (15%) had severe keratoconus at baseline. Fifteen eyes (75%) had allergic conjunctivitis and 20 eyes (100%) reported eye-rubbing. Cone location was central in 17 (85%) eyes and peripheral in 3 (15%) eyes. A mean of 2.21 ± 1.30 D (1.00 – 5.30 D) steepening was determined at Kmax 6 to 82 months following CXL treatment. Conclusions: Progression rate was found to be higher in the patients under the age of 17 years, female gender, allergic conjunctivitis, high preoperative Kmax (>57 D), thin corneas (

Dear Editor, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly pathogenic human coronavirus that can cause serious life-threatening respiratory disease and multiorgan failure(1). Despite the swift global spread of coronavirus disease 19 (COVID-19), no reliable clinical data are available to endorse any specific medical therapy. Organ-supportive therapy, including respiratory therapy, in acute pulmonary failure is recommended by physicians worldwide...

Migraine is thought to be a neurovascular disorder and increases the likelyhood to develop ischemic complications. Studies have shown that vascular disorders such as ischemic optic neuropathy, retinal artery and vein obstructions are more common in patients with migraine. This study aimed to evaluate the differences between retinal and optic disc microvasculature between migraine patients with and without aura and healthy controls using optical coherence tomography angiography (OCTA) imaging. Thirty-three patients with migraine and 28 healthy subjects were included in this prospective cross sectional study. Optical coherence tomography angiography imaging was performed for the macula and optic disc. Vessel densities (VD) and choriocapillaris flow values were compared between three groups: control group, migraine with aura (MWA), and migraine without aura (MWOA). There was no difference between the three groups for the VDs of the foveal, perifoveal, parafoveal, and the whole area. The choriocapillaris flow of patients with MWA was significantly less than that of the MWOA and control groups. The VDs of the optic disc revealed no significant difference between the three groups. A lack of choriocapillaris autoregulatory mechanisms may be a possible cause of the decrease in choriocapillaris flow in patients with MWA.

PubMed: 30617579 Purpose: To concurrently evaluate the effect of half-fluence photodynamic therapy (hf PDT) on choriocapillaris (CC) perfusion and choroidal structure in chronic central serous chorioretinopathy (CSC). Methods: This prospective study included 48 eyes of 41 patients with chronic CSC. Enhanced depth imaging optical coherence tomography and optical coherence tomography angiography (OCTA) images were analyzed. Choroidal area (CA), luminal area (LA), and stromal area (SA) were computed using Image J software. Results: One month after hf-PDT, total CA decreased to 1.312 mm 2 from 1.490 mm 2 (p < 0.001), LA decreased to 0.981 mm 2 from 1.097 mm 2 (p < 0.001), and SA decreased to 0.331 mm 2 from 0.393 mm 2 (p < 0.001). In OCTA, the CC flow in the eyes with CSC (17.75 mm 2 ) was statistically significantly lower than the fellow eyes (18.93 mm 2 ) at the baseline visit (p < 0.001). After hf-PDT, the flow in the choriocapillaris statistically significantly increased to 18.81 mm 2 at the first month (p = 0.02). Conclusions: OCTA proves that after hf-PDT a significant increase in CC perfusion occurred at first month. The decrease of the luminal areas in enhanced depth imaging optical coherence tomography is mainly due to a decrease in large-caliber vessels, which indicates that hf-PDT has an effect on larger choroidal vessels and spares CC flow. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

ÖZET Bu tez, tedarik süresi ve/veya talebin belirsiz ol duğu durumlarda emniyet stokunun belirlenmesi problemi ni incelemektedir, Genel olarak literatürde stok kontro- lu başlığı altında incelenen bu konu, belirli maliyet unsurlarıyla ye olasılıklı yaklaşımlarla ele alınmakta dır. Bu tezde olasılıklı yaklaşım kullanılarak verile rin oluşturulması sağlanmış ve emniyet stoku miktarını belirleyebilmek için Oyunlar Kuramı 'ndan yararlanılmış- tır.Bu teknik bizi akılcı bir sonuca ulaştırmıştır, öte yandan tezde, belirsizlik altında emniyet stok larının belirlenmesinde yeni bir yöntem kullanıldığı söylenebilir. ABSTRAIT Dans cette these, on examine le probleme de deter miner le stock de protection dans le cas ou. le delai d'approvisionnement et/ou la demande sont incertains. Ce sujet qui est examine en general dans la litera ture sous le titre de contröle du stock de protection, est traite` par les elements de cout determine` et par les approches probabilistes. Dans ce travail, on a procure la formation des donnees en utilisant l^pproche probabiliste et on a profite des Theories des Jeux pour pouvoir determiner la quantity du stock de protection. On a obtenu un re- sultat rationnel par cette technique. D' autre part, dans cette these, on peut dire qu'on a utilise une nouvelle me`thode pour determiner les stock de protection quand il s'agit d' une incertitude. II 78