جستجوی مقالات مرتبط با کلیدواژه « orbscan » در نشریات گروه « پزشکی »
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Purpose
To determine the repeatability of curvature measurements in 5 corneal rings (1–5 mm from the corneal center) in keratoconus (KCN) patients using the Orbscan and Pentacam and to compare the values of these devices.
MethodsForty-eight patients with a definite diagnosis of KCN were included in the study. Patients with any corneal scar or active disease or a history of ocular surgery were excluded from the study. The right eye of the patients was studied three times with the Orbscan and Pentacam. The repeatability of the curvatures of 5 corneal rings (1–5 mm from the corneal center) was evaluated using the Orbscan and Pentacam, and the agreement of their values was analyzed.
ResultsThe intraclass correlation coefficient (ICC) of three measurements was at least 0.94 (P < 0.0001) for the Orbscan and at least 0.88 (P < 0.0001) for the Pentacam in all corneal rings. According to the grade of KCN, the Orbscan had a low ICC in the 2 mm ring in grades 2 and 3 (ICC = 0.750 and 0.298, respectively). Repeated measures ANOVA showed no significant difference between the repeated measurements of the Orbscan and Pentacam in all corneal rings. The paired t-test showed a significant difference in curvature measurements in all rings except for the 5-mm ring between the two devices (P < 0.0001). The Bland-Altman plot showed a week agreement between these two devices in 1–4 mm corneal rings in curvatures more than 45 D.
ConclusionsAccording to the results of this study, keratometry readings are highly repeatable in Pentacam and Orbscan devices in all corneal rings. Despite the high correlation between curvature measurements of the Orbscan and Pentacam, there was a significant statistical and clinical difference between the results of two devices in all corneal rings (except the 5-mm ring), and the curvature measurements of the Pentacam were steeper than Orbscan measurements.
Keywords: Repeatability, Keratoconus, Keratometric values, Orbscan, Pentacam} -
هدفانحنای قدامی قرنیه نقش مهمی در تشخیص و درمان کراتوکونوس دارد. هدف مطالعه ی حاضر تعیین تکرارپذیری انحنای قدامی 5 حلقه قرنیه (5-1 میلی متری از مرکز قرنیه) در بیماران کراتوکونوس با هریک از دستگاه های ارب اسکن و Eyesys و تعیین میزان توافق مقادیر انحنایی بین دو دستگاه می باشد.روش بررسیدر این مطالعه ، انحناهای قدامی 5 حلقه ی قرنیه با ارب اسکن و Eyesys در 48 چشم راست از 48 بیمار مبتلا به کراتوکونوس اندازه گیری شد. درجه ی شدت کراتوکونوس بیماران بر اساس مقدار کراتومتری ماکزیمم شامل خفیف (دیوپتر50≥)، متوسط (دیوپتر 55-50) و شدید (دیوپتر 55≤) تقسیم بندی شد. برای نشان دادن توافق بین دستگاه ها و تکرار پذیری هر دستگاه از (Intraclass Correlation Coefficient; ICC) و آنالیز واریانس داده های تکراری و نمودار Bland-Altman استفاده شد.یافته هادر این مطالعه، تکرارپذیری بالایی برای مقادیر هر دستگاه در همه ی حلقه های قرنیه نشان داده شد (برای ارب اسکن حداقل 95/0 و برای Eyesys حداقل 0/99 ،p<0/0001). براساس آنالیز واریانس داده های تکراری، اختلاف معناداری بین مقادیر تکرار شده ی هر دستگاه در همه ی حلقه های قرنیه وجود نداشت. همبستگی بالایی بین مقادیر ارب اسکن با مقادیر Eyesys در همه ی حلقه های قرنیه نشان داد (0/84r≥، 0/0001p<). براساس آزمون تی زوجی بین مقادیر انحنایی Eyesys و ارب اسکن اختلاف معناداری وجود داشت (0/001p<).نتیجه گیریمطالعه ی حاضر نشان داد که مقادیر انحنایی قدامی بدست آمده با هر یک از دستگاه های ارب اسکن و Eyesys در همه ی حلقه های قرنیه تکرار پذیر بودند. مقادیر انحنای قدامی بدست آمده با Eyesys در 5 حلقه ی قرنیه استیپ تر از مقادیر بدست آمده با ارب اسکن بودند و دو دستگاه در اندازه گیری انحنای قدامی قرنیه در چشم های مبتلا به کراتوکونوس قابلیت جایگزینی با یکدیگر را نداشتند.کلید واژگان: انحنا قدامی قرنیه, ارب اسکن, Eyesys, کراتوکونوس}PurposeThe anterior corneal curvature has important role in diagnosis and management of keratoconus. The purpose of the present study is to determine the repeatability of anterior curvature of 5 corneal rings (1-5 mm from the corneal center) in keratoconus patients obtained by the Orbscan and Eyesys instruments and to determine the level of agreement of curvature measurements between two instruments.MethodsIn this prospective study, anterior curvatures of 5 corneal rings were measured using Orbscan and Eyesys in 48 right eyes of 48 keratoconic patients. The mean age of patients was 31.6±4.7 and the grades of keratoconus of patients according to the maximum keratometry were mild (≤50 D), moderate (50-55D) and severe (≥55D). Statistical analysis was performed using Intraclass Correlation Coefficient and Repeated measures ANOVA for repeatability of each device. Pearson’s correlation coefficient, paired t test and Bland-Altman plot were also used for comparison of two techniques.ResultsIn this study, the ICC showed high repeatability for measurements of each devices (ICC Eyesys=0.99, ICC Orbscan≥0.95, p<0.0001) in all corneal rings. According to repeated measures ANOVA, there was no significant difference between the repeated measurements of each device in all corneal rings. The Pearson’s correlation analysis showed high correlation between the measurements of Orbscan and those of Eyesys (r≥0.84, p<0.0001) in all rings. According to the paired t test, there was a significant difference in curvature measurements of Eyesys and those of Orbscan in all corneal rings (p<0.001). Also, the Bland-Altman plots showed low agreement between curvature measurements of two devices in all corneal rings.ConclusionThe present study showed that the anterior curvature measurements obtained by each of Orbscan and Eyesys instruments were repeatable in all corneal rings. Anterior curvature measurements of 5corneal rings obtained by Eyesys were steeper than those obtained by Orbscan and the two devices could not be replaced for anterior corneal curvature measurement in keratoconic eyes.Keywords: Anterior corneal curvature, Orbscan, Eyesys, Keratoconus}
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PurposeThe aim of this study was to determine the agreement between Pentacam HR (Scheimpflug imaging, Oculus) and Orbscan II (scanning slit topography, Bausch and Lomb) in measuring corneal parameters after photorefractive keratectomy (PRK) for hyperopia.MethodsIn this prospective cross‑sectional study, 38 hyperopic eyes undergoing PRK were examined before refractive surgery and 8 to 10 months postoperatively using Pentacam HR and Orbscan II. Ultrasound (US) pachymetry was also used to measure central corneal thickness (CCT). The radius of anterior (A‑) and posterior (P‑) best‑fit sphere size (BFS), central elevation (CE), and anterior maximum tangential power in 3 mm (TG3) and 3‑5 mm (TG5) zones, anterior chamber depth (ACD), and central corneal thickness (CCT) were collected and used in the analyses. To study the agreement between the measurements made by the two devices, the method described by Bland and Altman was used and the 95% limits of agreement were calculated.ResultsThe 95% limits of agreement show reasonable agreement between the measurements by Pentacam HR and Orbscan II for A‑BFS, P‑BFS, A‑TG3, and CCT, but not for A‑CE, P‑CE, A‑TG5, or ACD. CCT values obtained by both Pentacam HR and Orbscan II correlated well with the values determined by US pachymetry.ConclusionPentacam HR and Orbscan II after PRK for hyperopia show reasonable agreement for determining A‑BFS, P‑BFS, A‑TG3, and CCT, but not for A‑CE, P‑CE, A‑TG5, or ACD. CCT measurements with Pentacam HR have reasonable agreement with US pachymetry.Keywords: Hyperopia, Orbscan, Pentacam, Photorefractive Keratectomy}
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PurposeTo determine the repeatability of corneal thickness measurements with Scheimpflug (Pentacam) and slit scanning (Orbscan) imaging techniques in different grades of keratoconus.MethodsThis study was conducted as a cross-sectional research. Imaging with Orbscan and Pentacam was performed on patients with different grades of keratoconus. With each device, 3 measurements were taken at 10 min intervals. Repeatability indices in different grades of keratoconus were calculated for each device.ResultsSeventy-four eyes of 42 keratoconus patients were enrolled. Repeatability index (RI) of central corneal thickness (CCT) measurements in keratoconus grade 1, 2, and 3, were 12.8, 9.9, and 24.2 with Pentacam, and 23.6, 26.3, and 59.3 with Orbscan, respectively. For the thinnest point, these figures were 9.6, 8.0, and 35.7 with Pentacam and 19.5, 16.6, and 26.8 with Orbscan, respectively. The 95% limit of agreement (LOA) between Pentacam and Orbscan in measuring CCT and thinnest point in grade 1 were 25.5e47.7 mic and 33.3e32.8 mic, respectively. These results for grade 2 were 9.8e50.6 mic and 26.2 43.7 mic, respectively. In grade 3, 95% LoA were 20e64.6 mic and 31.4e60.5 mic, respectively.ConclusionsThe results of this study showed that although repeated measurements of the CCT with Orbscan and Pentacam are strongly correlated, repeatability values of CCT measurements significantly decrease at more advanced grades of keratoconus. In all keratoconus grades, repeatability of CCT measurements was better with Pentacam than Orbscan. These findings indicate that corneal thickness readings have less validity in patients with advanced keratoconus.Keywords: Corneal thickness, Orbscan, Pentacam, Keratoconus, Repeatability, Agreement}
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PurposeTo determine the distribution of anterior eye biometry indices, such as keratometry pachymetry, anterior chamber depth (ACD), pupil diameter, and corneal diameter, as measured by Orbscan instrument in a young Iranian population.MethodsA cross-sectional study was conducted, and subjects were selected through multistage cluster sampling from the students of Mashhad University of Medical Sciences. Objective and subjective refraction were performed followed by Orbscan imaging.ResultsA total of 1330 subjects were selected, 1121 of which participated in the study. After applying the exclusion criteria, the final analysis was performed on the data of 1051 subjects. The mean age of the participants was 26.1 ± 3.2 years (19e34 years old). The mean ± SD and 95% confidence interval (CI) of maximum keratometry, minimum keratometry, pupil diameter, corneal diameter, ACD, and central corneal thickness was 44.5 ± 1.7 (44.4e44.6), 43.1 ± 1.6 (43.0e43.2), 4.3 ± 0.9 (4.3e4.4), 11.7 ± 0.4 (11.7e11.7), 3.7 ± 0.3 (3.6e3.7), and 550.5 ± 35 (548.4e552.6), respectively. After adjusting for age and the mean spherical equivalent (MSE), maximum keratometry, minimum keratometry, central corneal thickness, and the thinnest pachymetry were statistically significantly higher in female subjects (PConclusionIn this study, the distribution of Orbscan measurements for the anterior segment parameters was reported in a large sample of the young Iranian population. Age, gender, and refractive error may affect the orbscan measurements.Keywords: Orbscan, Gender, Age, Anterior segment, Iran}
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Medical Hypothesis, Discovery and Innovation Ophthalmology Journal, Volume:5 Issue: 4, Winter 2016, P 125The porcine eye is often used as an ex vivo animal model in ophthalmological research. It is well-suited for investigations concerning refractive surgery; however, corneal topography data are scarce. This study investigated the corneal topography and pachymetry of the porcine eye to provide further reproducible data.
We evaluated freshly enucleated porcine eyes (n = 16) by performing computerized corneal topographies (Orbscan® IIz, Bausch and Lomb, USA). We assessed the steepest and flattest keratometric powers (K1 and K2 in diopters (D)), astigmatism (D), white-to-white (WTW) diameter (mm), thinnest point pachymetry (µm), anterior and posterior best-fit sphere (BFS) (D), refractive power of the anterior and posterior curvatures, and total refractive power of the cornea (D).
The mean keratometric powers were 39.6 ± 0.89 D (K1) and 38.5 ± 0.92 D (K2), and the mean astigmatism was 1.1 ± 0.78 D. The WTW diameter had a mean of 13.81 ± 0.83 mm, and the mean corneal thickness was 832.6 ± 40.18 µm. The BFSs were 38.14 ± 0.73 D (anterior) and 42.56 ± 1.15 D (posterior), and the mean refractive powers were 43.27 ± 1.08 D (anterior) and -5.15 ± 0.20 D (posterior); therefore, the mean of the total refractive power was 38.16 ± 1.00 D.
The topography and pachymetry of the porcine cornea showed a specific configuration differing from the human cornea. When using animal ex vivo models like porcine corneas for experimental corneal surgery, those findings have to be considered.Keywords: Topography, Porcine, Cornea, Orbscan, Corneal Thickness, Refractive Power} -
PurposeTo determine the sensitivity and specificity of anterior and posterior corneal elevation parameters as determined by Orbscan II (Bausch and Lomb, Rochester, NY, USA) in discriminating between (sub) clinical keratoconus (KCN) and normal corneas.MethodsThis prospective case‑control study included 28 eyes with subclinical KCN, 65 with clinical KCN and 141 normal corneas. Anterior and posterior corneal elevation was measured and compared in the central 5‑mm corneal zone using Orbscan II.ResultsReceiver operating curves (ROC) curve analyses for posterior corneal elevation showed predictive accuracy in both KCN and subclinical KCN with an area under the curve (AUC) of 0.97 and 0.69, respectively while optimal cutoff points were 51 μm for KCN and 35 μm for subclinical KCN. These values were associated with sensitivity and specificity of 89.23% and 98.58%, respectively, for KCN; and 50.00% and 88.65% for subclinical KCN. ROC curve analyses for anterior corneal elevation showed predictive accuracy in both KCN and subclinical KCN with AUC of 0.97 and 0.69, respectively while optimal cutoff points were 19 μm for KCN and 16 μm for subclinical KCN. These values were associated with sensitivity and specificity of 93.85% and 97.16%, respectively, for KCN; and 60.71% and 87.94% for subclinical KCN.ConclusionAnterior and posterior corneal elevation data obtained by Orbscan II can well discriminate between KCN and normal corneas, however the reliability of their indices is lower in differentiating subclinical KCN from normal cases.Keywords: Corneal Elevation, Keratoconus, Orbscan, Receiver Operating Curve, Sensitivity, Specificity}
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مقدمه و اهدافاین مطالعه جهت تعیین اعتبار دستگاه های ارب اسکن II و پنتاکمHR با تست استاندارد پاکی متری التراسونیک در افراد دوربین بعد از عمل جراحی لازک انجام گرفت.مواد و روش هااین مطالعه بروش توصیفی- تحلیلی انجام گردید.جامعه مورد بررسی، بیماران مراجعه کننده به بخش لیزیک بیمارستان فارابی بودند.جمع آوری نمونه ها از شهریور ماه سال 90 آغاز شد و بمدت 9 ماه بطول انجامید. در این مطالعه 28 چشم مبتلا به دوربینی که جراحی LASEK انجام داده بودند انتخاب شده و توسط سه دستگاه ارب اسکنII، پنتاکم HR و اولتراسوند پاکی متر مورد بررسی قرار گرفت. نتایج بدست آمده از 28 چشم پس از جمع آوری در نرم افزار آماری SPSS-18 با استفاده از روش آماری T-2test آنالیز شدند و مورد بررسی قرار گرفت.یافته هاارب اسکن II در اندازه گیری ضخامت مرکز قرنیه بعد از عمل همبستگی مناسبی با دستگاه اولتراسوند پاکی متر (083/0 r= و 05/0< p) و همینطور ارب اسکن II در اندازه گیری ضخامت مرکز قرنیه بعد از عمل همبستگی مناسبی نیز با دستگاه پنتاکم (072/0 r= و 05/0< p) داشت. در اندازه گیری منطقه محیطی قرنیه، پنتاکم همبستگی مناسبی با اولتراسوند داشته و در هیچکدام از مناطق محیطی اختلاف معنی داری مشاهده نشد. ارب اسکن نیز در 3 منطقه همبستگی مناسبی با التراسوند پاکی متر داشت و فقط در منطقه نازال اختلاف معنی داری مشاهده شد (37/0r=، 05/0< p و 74/2- =t، 01/0 = sig).نتیجه گیریپنتاکم HR و ارب اسکنII در منطقه 3 میلیمتر از مرکز قرنیه همبستگی مناسبی با اولتراسوند پاکی متر دارند اما در مناطق محیطی قرنیه دستگاه پنتاکم همبستگی مناسبی با دستگاه اولتراسوند پاکی متر داشت.
کلید واژگان: پنتاکم HR, ارب اسکن II, التراسوند, دوربینی, لازک}Background And AimTo determine the validity in central corneal thickness (CCT) peripheral corneal thickness (PCT) measured by Scheimpflug imaging (Pentacam, Oculus) and scanning-slit topography (ORBSCAN II, Bausch & Lomb) with that by gold standard method of ultrasound (US) in Hyperopic eyes after LASEK surgery.Materials And Methodsthe present study which was based on descriptive and analytic census that carried out in hyperopic patients who undergone LASEK eye surgery in Farabi eye hospital in 2012 and collection of samples lasted for 9 months. The subjects were inspect by ultrasound (US), Scheimpflug imaging (Pentacam, Oculus) and scanning-slit topography (ORBSCAN II, Bausch & Lomb). statistical analysis of collected data was performed using SPSS software version 18 and T-2test method.ResultsCT and PCT were evaluated in 28 eyes. CCT measured by Orbscan II had good correlation with those measured by ultrasound pachymetry(r=0.083 and p<0.05) also Orbscan II had good correlation in CCT measurement with Pentacam HR (p<0.05 and r=0.072).PCT measured by Pentacam HR had good correlation with those ultrasound pachymetry readings and there is no considerable discrepancy between two method. Orbscan II had good correlation in superior, inferior and temporal corneal thickness but there was considerable discrepancy in nasal corneal thickness measured by Orbscan II with those of ultrasound pachymetry (sig=0.01, t=-2.74, p<0.05).ConclusionPentacam HR and ORBSCAN II showed good correlation with US in CCT measurement but in PCT measurement Pentacam HR had better correlation comparing with ORBSCAN II for hyperopic patient after LASEK refractive surgeryKeywords: hyperopia, Pentacam HR, ORBSCAN, LASEK, Ultrasound} -
هدفتعیین حساسیت و ویژگی دو دستگاه گالیله و ارب اسکن در تشخیص قوز قرنیه تحت بالینی بر مبنای توپوگرافی.
روش پژوهش: بیماران براساس توپوگرافی به سه گروه قوز قرنیه، قوز قرنیه تحت بالینی و طبیعی تقسیم شده و با دستگاه های ارب اسکن و گالیله مورد ارزیابی قرار گرفتند. برجستگی خلفی قرنیه در سه میلی متری در گروه قوز قرنیه و قوز قرنیه تحت بالینی در تحلیل های جدا با قرنیه طبیعی مقایسه شدند. از منحنی های ROC برای ارزیابی دقت پیش گویی کننده و هم چنین تعیین نقاط برش (Cut off) استفاده شد تا حساسیت و ویژگی تشخیص قوز قرنیه و قوز قرنیه تحت بالینی از قرنیه طبیعی محاسبه گردد. تحلیل مشابه نیز در پنج میلی متری مرکزی ارب اسکن صورت گرفت.یافته هابا دستگاه گالیله متوسط برجستگی در سه میلی متری سطح خلفی قوز قرنیه 34.5±50.6 و قوز قرنیه تحت بالینی 4.3±12.8 و در مقایسه با قرنیه طبیعی 4.5±9.9 بالاتر بود. تحلیل منحنی ROC نشان داد که دقت پیشگویی کننده برجستگی خلفی برای قوز قرنیه و قوز قرنیه تحت بالینی بالا می باشد (سطح زیر نمودار به ترتیب 98 درصد و 71 درصد). حد مطلوب برای نقطه تغییر برش (Optimal cut off point) برای قوز قرنیه 18.5 میکرون و برای قوز قرنیه تحت بالینی 11.5 میکرون بود. این مقادیر با حساسیت و ویژگی 92 درصد و 95 درصد برای قوز قرنیه و 64.3 درصد و 75.7 درصد برای قوز قرنیه تحت بالینی بود. در ارب اسکن متوسط برجستگی در پنج میلی متری 43.7±106.8 در گروه قوز قرنیه و 22.8±36.6 در گروه قوز قرنیه تحت بالینی و 9.2±25 در قرنیه طبیعی بود. حد مطلوب برای نقطه برش (Optimal cut off point) برای قوز قرنیه 50 میکرون و برای قوز قرنیه تحت بالینی 33.5 میکرون بود، این مقادیر با حساسیت و ویژگی 89.1 درصد و 98.6 درصد برای قوز قرنیه و 50 درصد و 85 درصد برای قوز قرنیه تحت بالینی بود.نتیجه گیریبرجستگی خلفی قرنیه به طور موثری قوز قرنیه را از قرنیه طبیعی افتراق می دهد اما تاثیر آن برای تفکیک قوز قرنیه تحت بالینی کم تر است، بنابراین در این گروه از بیماران نباید فقط به برجستگی خلفی توجه نمود و باید به عنوان یک آزمون تکمیلی در موارد مشکوک مورد استفاده قرار گیرد.
PurposeTo determine the sensitivity and specificity of posterior corneal elevation in discriminating keratoconus and subclinical keratoconus from normal corneas by Galilei and Orbscan II diagnosed on the basis of topography.MethodsThree groups (keratoconus, subclinical keratoconus and normal) were evaluated with Galilei and Orbscan II and results were compared to those obtained by gold standard placido disc-based topography.In one eye of each patient, posterior corneal elevation was measured in the central 3 mm zones using the Galilei rotating double Scheimpflug camera. Posterior corneal elevation in keratoconus and subclinical keratoconus was compared to that in normal corneas. Receiver operating characteristic (ROC) curves were used to determine the test’s overall predictive accuracy (area under the curve) and to identify optimal posterior corneal elevation cut off points to maximize sensitivity and specificity in discriminating keratoconus and subclinical keratoconus from normal corneas. Similar analysis was done using Orbscan II,in the central 5mm zone.ResultsIn Galilei mean posterior corneal elevation in the 3 mm zone was statistically higher in keratoconus (50.6 ± 34.5 microns), and subclinical keratoconus (12.8 ± 4.3 microns) versus normal corneas (9.9 ± 4.5 microns). ROC curve analyses showed high overall predictive accuracy of posterior elevation for both keratoconus and subclinical keratoconus (area under the curve 98% and 71%, respectively). Optimal cutoff points were 18.5 microns for keratoconus and 11.5 microns for subclinical keratoconus. These values were associated with sensitivity and specificity of 92% and 95% respectively for keratoconus, and 64.3% and 75.7% for subclinical keratoconus. In Orbscan II mean posterior corneal elevation in the 5 mm zone was 106.8 ± 43.7 microns in keratoconus, 36.6 ±22.8 microns in subclinical keratoconus and 25 ± 9.2 microns in normal corneas. Optimal cutoff points were 50 microns for keratoconus and 33.5 microns for subclinical keratoconus.These values were associated with sensitivity and specificity of 89.1% and 98.6% respectively for keratoconus,and 50% and 85% for subclinical keratoconus.ConclusionPosterior corneal elevation very effectively discriminates keratoconus from normal corneas. Its accuracy is lower in subclinical keratoconus and thus data concerning posterior elevation hould not be used alone to stratify patients with this condition.Keywords: Galilei, Orbscan, Posterior Corneal Elevation, Anterior Corneal Elevation} -
Purpose
To compare thickness of central cornea measured using Pentacam, Orbscan II, and ultrasound pachymeter
MethodsPatients with no history of corneal diseases or systemic diseases affecting eyes, who did not wear contact lens or use eye medications, and who with no previous history of corneal surgery were selected for this study. Central corneal thickness (CCT) was measured by three methods using Pentacam, Orbscan II, and ultrasound pachymeter.
ResultsComparison of ultrasound and Orbscan CCT measurements showed a relatively high correlation between these two devices (P<0.001; r=0.891). The 95% limits of agreement (LoA) between these two devices were -42.44 to 20.18 µm. There was also a high correlation between the results obtained through ultrasound and Pentacam (P<0.001; r=0.932). The 95% LoA of CCT with ultrasound and Pentacam were -13.35 to 24.16 µm. There was also a high correlation between CCT measurements carried out by Orbscan and Pentacam (P<0.001) and the 95% LoA were -12.14 to 45.19 µm.
ConclusionThe findings of the present study demonstrated high agreements between the CCT readings measured with Orbscan, Pentacam, and ultrasound. The agreement between the Pentacam and ultrasound measurements was higher than that of between Orbscan and ultrasound, making Pentacam a better substitute for ultrasound.
Keywords: Central Corneal Thickness, Orbscan, Pentacam, Ultrasound, Agreement} -
زمینه و هدفبا افزایش جراحی های لیزری در اصلاح عیوب انکساری و اهمیت اندازه گیری ضخامت قرنیه قبل از انجام اعمال جراحی اصلاح عیوب انکساری چشم، تعیین دقیق ضخامت قرنیه در انجام این روش ها دارای اهمیت می باشد. اندازه گیری ضخامت قرنیه (Pachymetry) به دو روش Optical با استفاده از دستگاه ارب اسکن (Orbscan) و اولتراسوند (Ultrasound) انجام می شود. لذا این مطالعه برای مقایسه نتایج تعیین ضخامت قرنیه با استفاده از دو روش فوق انجام شد.روش بررسیدر یک مطالعه توصیفی - تحلیلی 324 چشم از 324 بیمار مراجعه کننده به کلینیک چشم پزشکی آبان اصفهان مورد بررسی قرار گرفت. ضخامت قرنیه با استفاده از دستگاه ارب اسکن و دستگاه اولتراسوند در هر چشم اندازه گیری شد و با استفاده از تست های آماری t-test، t زوجی، آنالیز واریانس و آزمون همبستگی مورد تجزیه و تحلیل آماری قرار گرفت.یافته هامیانگین و انحرف معیار ضخامت قرنیه بیماران با استفاده از دستگاه اولتراسوند 26.23±504.28 میکرون و دستگاه ارب اسکن 35.94±484.4 میکرون بدست آمد که اختلاف دو گروه از نظر آماری معنی دار می باشد (0.001>p).نتیجه گیریاندازه گیری ضخامت قرنیه با استفاده از دستگاه های ارب اسکن و اولتراسوند نتایج متفاوتی دارد و باید دقت کرد که در اعمال جراحی که بر اساس جدول مربوط به پاکیمتری اولتراسوند تنظیم شده است نباید بر اساس اعداد پاکیمتری ارب اسکن اقدام به انجام جراحی نمود.
کلید واژگان: اولتراسوند, ارب اسکن, پاکیمتری, ضخامت قرنیه}Background And AimWith increased popularity of laser surgeries as a treatment for refractory errors and importance of pre-operative pachymetry for decreasing the complications of refractive surgery, correct measurement of corneal thickness is an important refractive procedure. There are two methods of corneal thickness measurement (phachymetry), optical method with orbscan system and ultrasonic method. This study was performed to compare the efficacy of these two methods in phachymetry.MethodsCorneal thicknesses of 324 eyes were measured with both orbscan and ultrasound phachymetry. Statistical analysis was performed using t-, ANOVA and correlation tests.ResultsCorneal thickness was 504.28±26.23µ using ultrasound pachymetry and 484.4±35.94µ using orbscan system. The difference between the two methods was statistically significant (p<0.001).ConclusionCorneal thickness measurement with orbscan and ultrasound systems might reveal different results and refractive surgeons should pay attention to this point.Keywords: Phachymetry, Ultrasound, Orbscan, Corneal thickness}
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