Standardized classification of mechanical ocular injuries: Efficacy and shortfalls

Objectives: The aim of this study was to examine the efficacy and the shortfalls of the Birmingham Eye Trauma Terminology classification system for ocular trauma in predicting the visual outcome. Methods: The records of 256 eyes of 246 patients with a diagnosis of mechanical ocular trauma admitted to the Osman Gazi University Hospital ophthalmology department between 1995 and 2000 were retrospectively reviewed. The zone, type, grade, and pupil status of the injuries were determined according to the Birmingham classification system. Injuries with a good prognosis were defined as injuries that resulted in vision of equal to or better than counting fingers at 1 meter. Fischer’s exact test was used to determine the statistical significance of relationships between the final visual acuity and the initial clinical findings. Results: Open eye injuries restricted to zone I, those with no afferent pupillary defect, and those graded as 3 or better or classed as type B were significantly associated with a better visual outcome (p<0.05). Open eye injuries that extended to zone III, had an afferent pupillary defect, or were graded as 4 or worse were significantly associated with a poorer visual outcome (p<0.05). Closed eye injuries classified as type B or grade 4 were significantly associated with a poor visual outcome (p<0.05). Conclusion: The Birmingham classification system for mechanical ocular trauma offers a standardized method for both open and closed eye injuries, however, adding subclasses to type C (injuries with foreign body involvement) could enhance the classification method and help to understand the influence of foreign body properties and sizes on the outcome

Experimental laboratory modeling of choroidal vasculature: A study of the dynamics of intraoperative choroidal hemorrhage during pars plana vitrectomy

Amaç: Koroid kanamaları (KK), koroid damarlarının rüptürü ve kanın supra koroid boşluğuna ekstravazasyonu ile meydana gelir. Koroid damar sistemini daha iyi şekilde anlamak için, bu çalışmada amaca yönelik olarak ölçeklendirilmiş bir model kullanıldı. Bu model aracılığıyla, koroid damar sistemindeki stres düzeyleri farklı koşullar altında ölçüldü. Gereç ve Yöntem: Koroid damar yapısı modelinde, 1 cm genişliğinde ve 10 cm uzunluğunda lastik bir tüp kullanıldı. Modeldeki stres seviye ölçümü için ise özel iletken iplik kullanıldı. Modeldeki stres seviyeleri, farklı sistemik intravasküler kan basıncı seviyeleri (İVB), farklı göz içi basınç seviyeleri (GİB) ve farklı distorsiyon seviyeleri altında ölçüldü. Bulgular: Koroid damar modelindeki stres değerleri GİB ile negatif, İVB ve distorsiyon ile pozitif korelasyon gösterdi. Tüm korelasyonlar istatistiksel olarak anlamlı idi (p<0,05). Ancak, modelde ekspansil tamponad kullanıldığında bu korelasyon ekspansil olmayan tamponadlara göre daha kuvvetliydi. Distorsiyonun stres ile korelasyonu, İVB’nin korelasonuna göre daha güçlü idi. İVB’nin stres ile korelasyonu ise, GİB’nin korelasonuna göre daha güçlü idi. Distorsiyondan kaynaklanan damar yapısındaki stres, yüksek GİB etkisi ile karşılaştırıldığında gerileme gösterirken, yüksek İVB’den kaynaklanan damar yapısındaki stres tam tersine hafif bir artış sergiledi. Sonuç: Cerrahi işlemler sırasında göz küresinin aşırı distorsiyonu, nadiren görülen intraoperatif KK’lerin başlıca nedeni olabilir. Ekspansil olmayan oküler tamponat kullanımı, koroid kanamasına karşı vasküler yatak için daha iyi destek sağlar ve koroid kanaması saptanan hastalarda önerilen tampon çeşidi olmalıdır. GİB’nin aşırı artırılması, distorsiyondan kaynaklanan koroid damarlarındaki kanama riskinin önlenmesinde sınırlı etkiye sahiptir.Objectives: Choroidal hemorrhages (CH) result from rupture of choroidal vessels leading to extravasation of blood into the suprachoroidal space. In this study, we aimed to understand the hemodynamics of CH by developing a purpose-built scale model of the choroidal vasculature and calculating stress levels in the model under different conditions. Materials and Methods: We modeled the choroidal vasculature using a rubber tube 10 cm in length and 1 cm in diameter that was wrapped with conductive thread to enable the measurement of stress at the walls of the tube. Stress levels across the tube were continuously measured under different systemic intravascular blood pressure levels (IVP), intraocular pressure (IOP) levels, and distortion. Results: Stress values across the choroidal vessel model correlated negatively with IOP and positively with IVP and distortion. All correlations were statistically significant (p<0.05) and were stronger when the model was filled with expansile tamponade compared to non-expansile tamponades. Distortion showed the strongest correlation in terms of increasing stress across the model, while IVP showed stronger correlation compared to IOP. Raising IOP to counteract the stress in the model was effective when the stress in the model was secondary to increased IVP, but this approach was not effective when the stress in the model was caused by distortion. Conclusion: Excessive distortion of the globe during surgical maneuvers could be the primary reason for the rarely observed intraoperative CH. Non-expansile ocular tamponade provides better support for the vascular bed against CH and should be the recommended choice of tamponade in patients with existing CH. Increasing IOP excessively is of limited effect in preventing CH in vessels that are under stress as a result of distorting surgical maneuvers

Experimental laboratory modeling of choroidal vasculature: A study of the dynamics of intraoperative choroidal hemorrhage during pars plana vitrectomy

Objectives: Choroidal hemorrhages (CH) result from rupture of choroidal vessels leading to extravasation of blood into the suprachoroidal space. In this study, we aimed to understand the hemodynamics of CH by developing a purpose-built scale model of the choroidal vasculature and calculating stress levels in the model under different conditions. Materials and Methods: We modeled the choroidal vasculature using a rubber tube 10 cm in length and 1 cm in diameter that was wrapped with conductive thread to enable the measurement of stress at the walls of the tube. Stress levels across the tube were continuously measured under different systemic intravascular blood pressure levels (IVP), intraocular pressure (IOP) levels, and distortion. Results: Stress values across the choroidal vessel model correlated negatively with IOP and positively with IVP and distortion. All correlations were statistically significant (p<0.05) and were stronger when the model was filled with expansile tamponade compared to non-expansile tamponades. Distortion showed the strongest correlation in terms of increasing stress across the model, while IVP showed stronger correlation compared to IOP. Raising IOP to counteract the stress in the model was effective when the stress in the model was secondary to increased IVP, but this approach was not effective when the stress in the model was caused by distortion. Conclusion: Excessive distortion of the globe during surgical maneuvers could be the primary reason for the rarely observed intraoperative CH. Non-expansile ocular tamponade provides better support for the vascular bed against CH and should be the recommended choice of tamponade in patients with existing CH. Increasing IOP excessively is of limited effect in preventing CH in vessels that are under stress as a result of distorting surgical maneuvers

Retinal detachment associated with viral retinitis

Viral retinitler 0.63/1000000/yıl oranında sıklığı olan, viral etkenlerin neden olduğu nekrotizan, vazo-okluzif inflamasyondur. Klinik pratikte olguların % 90 ını akut retinal nekroz ve sitomegalovirus retiniti oluşturur. Viral retinit olgularının % 65 inde retina dekolmanı gelişir. Viral retinit ilişkili retina dekolmanları hemen her zaman regmatojen ve traksiyonel faktör içerir. Olguların çoğunda vitreus opaktır ve proliferatif vitreoretinopati eşlik eder. Viral retinitlerde tedavi pars plana vitrektomi, silikon yağı injeksiyonudur. Silikon yağı sadece tamponad amaçlı değil silikon yağının antiviral etkisinden yaralanmak amacıyla da kullanılır. Anatomik başarının sınırlı olduğu bu tip retina dekolmanlarında ameliyat sonrası görülen optik atrofi, kistoid makula ödemi, epiretinal membran, proliferatif vitreoretinopati ve hipotoni fonksiyonel ve morfolojik başarıyı sınırlayan başlıca durumlardır.Viral retinitis of which incidence is 0.63/1000000 per year, is a necrotizing, vaso-occlusive retinopathy. In practice, 90 % of cases are acute retinal necrosis in which etiological agents are Varicella Zoster Virus and Herpes Simplex Virus and Cytomegalovirus retinitis. 65 % of patients with viral retinitis develop retinal detachment. Retinal detachment due to viral retinitis are almost-always rhegmatogenous and tractional and associated with proliferative vitreoretinopathy. Pars plana vitrectomy combined with silicone oil injection is the most commonly used techniques for the treatment of retinal detachment associated with viral retinitis. Optic atrophy, chronic cystoid macular edema, epiretinal membrane, proliferative vitreoretinopathy and hypotony are most commonly seen complications which are limiting functional improvement

Retinitis pigmentosa; epidemiology, pathophysiology and classification

Retinitis pigmentosa (RP) en sık görülen kalıtsal retina dejenerasyonudur. Öncelikle rod ve daha sonra kon fotoreseptörlerini etkiler. RP, rod fotoreseptör işlev bozukluğunu yansıtan gece körlüğü ve periferik görme alanı kaybı ile kendini gösterir. Kistoid maküla ödemi dışında merkezi görme keskinliği kaybı kon fonksiyon kaybının olduğu son dönemde görülür. RP’nin klasik olarak tarif edilen fundus görünümü retina pigment epitelinin atrofisine bağlı granüler görünüm, kemik spekülü pigmentasyon, retina damarlarında incelme ve optik disk solukluğunu içerir. RP Mendelian otozomal dominant, otozomal resesif, veya X’e bağlı geçiş formlarında görülebilir. Mitokondriyal digenik formlarda nadiren görülmektedir. Ancak sporadik veya simpleks en sık görülen formdur. Son zamanlarda gen belirleme çalışmalarında büyük ilerleme kaydedilmiştir. Bu derlemede RP’nin klinik, genetik, fundus fotoğrafı, optik koherens tomografi, fundus otoflöresans, mikroperimetri, karanlık adaptometre ve oküler elektrofizyolojik özellikleri hakkında kapsamlı bir genel bakış sunulmaktadır.Retinitis pigmentosa (RP) is the most common hereditary retinal degeneration. It primarily affects rods and then after cone photoreceptors. RP manifests with night blindness and concentric visual field loss, reflecting the dysfunction of rod photoreceptors. Central visual acuity loss occurs last period of disease due to cone dysfunction; otherwise, macula involvements like cystoid macular edema. Classically described fundus appearance of RP includes mottling and granularity of the retina pigment epithelium, bone spicule intraretinal pigmentation, attenuated retinal vessels, and optic disc head pallor. RP can be transmitted as Mendelian’s an autosomal dominant, autosomal recessive, or X-linked trait. Mitochondrial or digenic forms also rarely have been described. However, the sporadic or simplex form is the most commonly seen in the clinic. Recently great progress has been made in the identification of the causative genes. This review presents a comprehensive overview of the clinical, genetic and fundus photography, optical coherence tomography, fundus autofluorescence, microperimetry dark adaptometer, and ocular electrophysiology characteristics of RP

Humerus proksimal uç iki parçalı kırıklarının tek yönlü ve çok yönlü Kirschner teli ile tespitinin biyomekanik olarak karşılaştırılması

Objectives: The stability and effectiveness of uni-planar Kirschner wire (K-wires) was compared to multi-planar K-wires osteosynthesis combined with tension band wiring for fixation of two-part osteoporotic surgical neck fracture of the proximal humerus. Materials and methods: Two groups each with eight cadaveric elderly (mean age 72.6; range 70 to 80 year) frozen human humeri were used in the study. Transverse osteotomy of the proximal humerus was performed using a thin oscillating saw. The first group (group A) was fixed using two anterograde smooth K-wires, sent from lateral cortex, combined with tension band wiring. The second group (group B) was fixed using multi-planar (anterograde and retrograde) four smooth K-wires combined with tension band wiring on the lateral cortex. Biomechanical tensile properties for 3 mm displacement (gap load) and maximum load were assessed. Results: The mean value for the gap load was 1045.0&plusmn;45.4 N (Newton) for group A and 1238.1&plusmn;115.8 N for group B. Gap load values of groups were similar (p=0.01). The maximum load was 1261.8&plusmn;52.4 N in group A and 1471.1&plusmn;107.3 N in group B. The maximum load values were statistically higher in the multiplanar fixation technique (group B) when compared to that of the uniplanar fixation technique (group A), (p=0.004). Conclusion: Fixation in osteoporotic two-part surgical neck fractures of the proximal humerus using multiplanar K-wires combined with tension band wire provides substantially more effective stability compared to that of uniplanar fixation.Amaç: Humerus proksimal uç cerrahi boyun iki parçalı kırıklarında tek yönlü Kirschner teli (K-teli) ile tespit yönteminin stabilite ve etkinliği, çok yönlü K-teli ve gergi bandı yöntemi ile biyomekanik olarak karşılaştırıldı.Gereç ve yöntemler: Çalışma iki grup halinde düzenlendi. Her bir grupta sekizer adet dondurulmuş insan (ort. yaş 72.6; dağılım 70-80 yıl) kadavra humerus kemiği kullanıldı. Humerus proksimalinde ince el testeresi yardımı ile transvers osteotomi yapıldı. Birinci grupta (grup A) gergi bandı yöntemi ile güçlendirilen ve lateral korteksten antegrad olarak gönderilen iki adet düz K-teli ile tek yönlü tespit uygulandı. İkinci grupta ise lateral kortekste gergi bandı yöntemi ile güçlendirilmiş dört adet K-teli ile çok yönlü (antegrad ve retrograd) tespit uygulandı. Üç milimetre aralık oluşma sırasındaki yüklenme (ayrışma gücü) ve maksimum yüklenme miktarları biyomekanik olarak değerlendirildi. Bulgular: Ortalama ayrışma gücü, grup A’da 1045.0±45.4 N (Newton) ve grup B’de 1238.1±115.8 N olarak tespit edildi. Ayrışma gücü açısından, iki grup benzerdi (p=0.01). Maksimum yüklenme miktarı grup A’da 1261.8±52.4 N, grup B’de ise 1471.1±107.3 N olarak bulundu. Maksimum yükleme değerleri, çok yönlü tespit tekniğinde (grup B), tek yönlü tespit tekniğinden (grup A) istatiksel olarak yüksek bulundu (p=0.004). Sonuç: Humerus proksimal uç iki parçalı cerrahi boyun kırıklarının sabitlenmesinde, gergi bandı ve K-telleri ile güçlendirilmiş çok yönlü tespit yöntemi, tek yönlü tespit yöntemine göre daha etkilidir

Humerus distal kırıklarında çift plak osteosentezi, çift gergi bandı tekniğinden daha iyi biyomekanik stabilizasyon sağlar

Objectives: In this study we evaluated the stability and effectiveness of the double tension band osteosynthesis technique compared to the double plate osteosynthesis technique used for fixation of distal humerus fractures. Materials and methods: The study was performed on two groups, and in each group eight cadaveric, elderly (mean age 70-80) human humeri was used. An osteotomy was performed in the supracondylar region using a manual saw. The first group (group 1) was fixed with double 3.5 mm reconstruction plates, while the second group (group 2) was fixed with the double tension band technique, using crossing Kirschner wires. The osteotomy was designed so that the distal fragment would allow only a single screw per plate. The constructs were evaluated using a material testing machine. A linear non-cyclic load was applied until the failure of the constructs. The force which produced a 3 mm gap (3 mm gap strength), as detected visually with the aid of operating loupes, and the maximum load prior to failure of the fixation (maximum force) were measured from all tests. Results: The mean value for the 3 mm gap strength was 1356.29&plusmn;226.97 N for group 1 and 882.63&plusmn;305.21 N for group 2. The mean value of the maximum load strength was 1487.13&plusmn;298 N for group 1 and 1232&plusmn;107.62 N for group 2. There were significant differences in 3 mm gap strengths of the two groups (p=0.005). There was also a significant difference in the maximum load between the two groups (p=0.016). Conclusion: Double plate osteosynthesis technique is superior to double tension band osteosynthesis for the fixation of distal humerus fractures.Bu çalışmada Doğu Karadeniz bölgesi hamsilerinin avlama mevsimi süresince besin bileşenleri ve yağ asitleri komposizyonundaki aylık değişim incelenmesi amaçlanmıştır. Hamsilerin nem oranı ekim ayında en düşük (%64,93) iken nisan ayında ise en yüksek seviyeyede (%74,32) olduğu hesaplanmıştır (P<0,05). Buna bağlı olarak tüm aylardaki yağ seviyeleri ve aralık ve nisan aylarındaki kül miktarlarındaki değişim istatistiksel açıdan önemli bulunmuştur. İlaveten, avlanma mevsimi süresince doymuş yağ asitlerinden (SFA) C16:0, C14:0 ve C18:0, tekli doymamış yağ asitlerinden (MUFA) C18:1n9 ve çoklu doymamış yağ asitlerinden (PUFA) C22:6n-3 (DHA, dekosahekzanoik asit) ve C20:5n-3 (EPA, eikosapentanoik asit) en yüksek oranlarda bulunmuşlardır. Avlama mevsimi boyunca, ortalama omega–3 ve omega–6 değerleri sırası ile %30,33 ve %4,43 olarak hesaplanmıştır. EPA seviyesinde tedrici olarak bir azalma meydana gelirken, DHA seviyesinde ise ekim ayından nisan ayına kadar bir artış gözlenmiştir. Yağ asitlerinde av mevsimi boyunca yağ assitlerinde özellikle de DHA oranında belirgin bir şekilde bir değişimin olduğu gözlemlenmiştir

In vivo generated autologous plasmin assisted vitrectomy in young patients

Background Autologous plasmin enzyme facilitates the induction of posterior vitreous detachment(PVD) during vitrectomy in young patients. We proposed the concept of in-vivo generated plasmin which is based on the injection of tissue plasminogen activator(t-PA) and autologous whole blood(AWB) into the vitreous cavity. The purpose of this pilot study is to report the efficacy of preoperative simultaneous intravitreal injection of(t-PA) and autologous whole blood in facilitating the intraoperative induction of PVD in young patients with various vitreoretinal pathologies. Methods Seventeen eyes of 16 young patients with various vitreoretinal pathologies requiring vitrectomy, who received simultaneous intravitreal injection of 0.1 ml of AWB and 25 mu g of t-PA, 3 days prior to surgery were retrospectively reviewed. Outcome measures were the number of attempts required to achieve successful intraoperative separation of the posterior hyaloid; the postoperative visual acuity; and intraoperative and postoperative complications. Results The mean age of the patients was 23.87 +/- 10.09 years, ranging from 10 to 39 years. Eight of 16 patients were men. The mean follow-up time was 19.35 +/- 5.04 months, ranging from 12 to 26 months. Surgical indications for vitrectomy were chronic retinal detachment (n = 7), traumatic retinal detachment without proliferative vitreoretinopathy(n = 3), traumatic macular hole(n = 1), secondary vasoproliferative tumor(n = 4) and optic pit maculopathy(n = 2). Patients with retinal detachment complicated with PVR and those who were older than 40 years of age were excluded from the study. Separation of the Weiss ring from the optic nerve head was achieved intraoperatively in all cases, with a mean number of 2.86 +/- 1.4 attempts. While the mean preoperative LogMAR visual acuity was 1.38 +/- 0.59, ranging from 2.40 to 0.50, it was a mean of 0.51 +/- 0.29, ranging from 1.00 to 0.10 at final postoperative exam(p < 0.001; paired samples t-test). No preoperative or intraoperative complications were noted. Conclusion Preoperative simultaneous intravitreal injection of 25 mu g t-PA with 0.1 ml of AWB facilitates the intraoperative induction of posterior vitreous detachment in young patients