Biomedical subjects

Mana Tehrani

Publications and source records attributed to Mana Tehrani.

At least 19 recordsLinked to original sources

PubMed2007

Preoperative simulation of postoperative iris-fixated phakic intraocular lens position and simulation of aging using high-resolution Scheimpflug imaging.

To increase postoperative safety after implantation of iris-fixated phakic intraocular lenses (pIOLs), optimal preoperative evaluation and patient selection is mandatory. We present a new software tool in a high-resolution Scheimpflug imaging device that precisely simulates the postoperative position of an iris-fixated pIOL and also simulates the effect of aging on the pIOL's position.

Adult↗

PubMed2006

Changes in higher-order aberrations after implantation of a foldable iris-claw lens in myopic phakic eyes.

PURPOSE: To evaluate the change in higher-order aberrations (HOAs) after implantation of a foldable iris-claw phakic intraocular lens (pIOL) in myopic eyes. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: This prospective nonrandomized comparative self-controlled trial included 41 eyes that had implantation of a foldable iris-claw pIOL between July 2003 and November 2004. All patient data for HOAs (Zernike coefficient) were measured and calculated using the same pupil size preoperatively and postoperatively, and the root-mean-square (RMS) wavefront error was calculated. Examinations were performed preoperatively as well as 1 week and 3, 6, and 12 months after pIOL implantation. RESULTS: The mean preoperative sphere was -8.12 diopters (D) +/- 2.01 (SD) (range -12.25 to -3.75 D) and the mean preoperative cylinder, -0.90 +/- 0.62 D (range -2.50 to 0.00 D). The Z3(1) and Z(3)(-1) coefficients decreased after implantation of the foldable iris-claw pIOL, but the decrease was not statistically significant (P = .078 and P = .45, respectively). There was a statistically significant reduction in Z4(0) in the first postoperative week (P = .038), but the decrease was not significant thereafter. There was a statistically significant reduction in total RMS wavefront error from preoperatively to all values postoperatively (P = .008). CONCLUSION: Over a 12-month follow-up, 3rd-order and 4th-order HOAs did not increase after foldable iris-claw pIOL implantation in myopic eyes.

Anterior Chamber↗

PubMed2006

Surgical management of acute angle-closure glaucoma after toric implantable contact lens implantation.

A case of pupillary block after implantation of an implantable contact lens (ICL) is reported, and surgical management and prevention are discussed. In a myopic patient, the best corrected visual acuity in the right eye was 20/50 with -15.50 -3.00 x 175. After uneventful implantation of an ICL, painful acute glaucoma developed with an intraocular pressure beyond measurable values. Apparent anterior vaulting of the ICL suggested a sizing problem. In a situation of a mid-wide dilated pupil, immediate explantation of the ICL was performed. Then, using a preoperative iris photography as guidance, an anterior chamber iris-claw toric phakic intraocular lens was implanted. On postoperative examination, the anterior chamber was deep, the angle open, the natural lens clear, and uncorrected visual acuity was 20/40.

Acute Disease↗

PubMed2006

Iris-fixated toric phakic intraocular lens: Three-year follow-up.

PURPOSE: To evaluate the 3-year safety, efficacy, predictability, and stability of iris-fixated toric phakic intraocular lens (pIOL) implantation for the correction of myopia or hyperopia with astigmatism. SETTING: Department of Ophthalmology, Johannes Gutenberg University, Mainz, and Department of Ophthalmology, University Clinic, Bochum, Germany. METHODS: A prospective clinical trial of 40 eyes of 23 patients with high ametropia and astigmatism was conducted. Best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity, refraction, astigmatism, intraocular pressure, slitlamp biomicroscopy, and indirect ophthalmoscopy were measured preoperatively and postoperatively. RESULTS: Of the 40 eyes, 28 were myopic and 12 were hyperopic. Three years postoperatively, 70% of eyes were within +/-1.00 diopter (D) of the targeted refraction. In the myopic group, mean preoperative BSCVA was 20/40 and improved postoperatively to 20/25. Sixty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.58 D +/- 1.26 (SD) preoperatively to -1.15 +/- 1.01 D postoperatively. In the hyperopic group, preoperative BSCVA was 20/25 and improved to 20/20 postoperatively. Thirty-six percent of eyes gained 1 or more lines from the preoperative BSCVA. The mean cylinder decreased from -3.37 +/- 0.88 D to -1.53 +/- 0.69 D postoperatively. The correction was stable in all eyes 3 years after surgery. No potentially sight-threatening complications occurred. CONCLUSION: The 3-year follow-up showed the iris-fixated toric pIOL was effective in correcting high ametropia and astigmatism.

Adult↗

PubMed2006

Scheimpflug biometry of the anterior segment after implantation of foldable iris-fixated lenses.

PURPOSE: To evaluate intraocular dimensions of the anterior segment of myopic phakic eyes after implantation of foldable iris-fixated lenses. METHODS: Seventeen myopic eyes that received a foldable iris-fixated phakic intraocular lens (PIOL) were assessed. Distances between the cornea and the IOL-optic edge and between the IOL optic and the crystalline lens were evaluated using Scheimpflug photography 3 months postoperatively. RESULTS: The average postoperative distance between the central corneal endothelium and the anterior surface of the IOL was 2.01 +/- 0.26 mm. The distance between the corneal endothelium and the peripheral edge of the IOL averaged 1.32 +/- 0.18 mm at the 12 o'clock position and 1.34 +/- 0.21 mm at the 6 o'clock position. The distance between the crystalline lens and the posterior surface of the IOL averaged 0.73 +/- 0.09 mm. CONCLUSIONS: The high quality of the three-dimensional Scheimpflug images allowed measurements of intraocular distances in PIOL implanted eyes. Distances between the foldable iris-fixated IOL and crucial surrounding tissues could be determined 3 months postoperatively.

Adult↗

PubMed2005

Short-term follow-up after implantation of a foldable iris-fixated intraocular lens in phakic eyes.

OBJECTIVE: To evaluate efficiency, predictability, stability, complications, and patient satisfaction after implantation of a foldable iris-fixated phakic intraocular lens (PIOL) for the correction of myopia. DESIGN: Prospective, nonrandomized, comparative (self-controlled) trial. PARTICIPANTS: Forty-one eyes of 22 myopic patients aged 18 to 56 years (mean, 36 years) with average sphere of -8.2+/-2.01 diopters (D; range, -12.25 to -3.75 D) and average preoperative cylinder of -0.90+/-0.62 D (range, -2.50 to 0.00 D) were enrolled in this prospective study. METHODS: All eyes underwent implantation of a foldable iris-fixated PIOL with an optical zone of 6.0 mm. The follow-up was 6 months in all cases. Phakic intraocular lenses were available in powers ranging from -2.0 D to -12.0 D. MAIN OUTCOME MEASURES: The main parameters assessed were best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity, refraction, endothelial cell count, intraocular pressure, slit-lamp biomicroscopy, and indirect ophthalmoscopy. RESULTS: At 6 months' follow-up, no eyes experienced a loss in BSCVA and 78% gained 1 or more lines of their preoperative BSCVA. Uncorrected visual acuity was significantly improved, with 82% of eyes reaching 20/25 or better. There was a significant reduction in spherical errors in all patients after surgery. Ninety-one percent of eyes were within +/-0.50 D of target refraction. A slight loss of endothelial cells (2.3 %) was observed 6 months after surgery. There were no intraoperative complications. In the postoperative follow-up, however, pigment precipitates were noted in 5 eyes of 4 patients. CONCLUSIONS: At short-term follow-up, the implantation of the foldable iris-fixated PIOL proved to be effective and predictable for the correction of myopia in phakic eyes. However, longer follow-up with larger numbers of patients is necessary to evaluate long-term complications.

Adolescent↗

PubMed2005

Change in pupil size after implantation of an iris-fixated toric phakic intraocular lens.

PURPOSE: To evaluate the changes in pupil size after implantation of an iris-supported toric phakic intraocular lens (TPIOL) for correction of myopia and hyperopia with astigmatism. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: Twenty-two myopic eyes and 9 hyperopic eyes were included in the study. The mean age of the 2 groups was 34 years and 40 years, respectively. The scotopic pupil size was measured with a handheld infrared pupillometer (Colvard, Oasis Medical) before and 6 months after implantation of the TPIOL. All examinations were performed under scotopic conditions after 2 minutes of dark adaptation with the fellow eye covered. Intraindividual comparisons were made between preoperative and postoperative pupil sizes. The relationship between implanted IOL power and postoperative pupil width in each group was studied to determine whether lens magnification could lead to misinterpretation of the results. The difference between horizontal and vertical postoperative pupil diameters was assessed in eyes with horizontally aligned IOLs to determine the potential mechanical effect of the TPIOL on pupil size. RESULTS: The mean scotopic pupil diameter decreased significantly from 4.7 mm (range 3.0 to 6.0 mm) preoperatively to 3.6 mm (range 2.0 to 5.0 mm) postoperatively in myopic eyes and from 5.0 mm (range 4.0 to 6.0 mm) to 4.0 mm (range 2.0 to 5.0 mm) in hyperopic eyes. No significant correlation between the power of the TPIOL and the postoperative pupil size diameter was found, confirming that the IOL did not distort measurements of pupil size. Comparing horizontal and vertical pupil diameters under medical mydriasis revealed reduced pupil size in the axis of enclavation. CONCLUSIONS: The scotopic pupil diameter decreased by a mean of 1.1 mm in myopic eyes and 1.0 mm in hyperopic eyes after implantation of the iris-supported TPIOL. Postoperative pupil size was not related to IOL power, patients' emotional states, or other factors. The slightly smaller pupil diameter in the axis of enclavation suggests that this fixation method restricts pupil size under scotopic conditions, which could reduce the incidence of postoperative photic phenomena.

Adult↗

PubMed2004

Impact of the line of sight on toric phakic intraocular lenses for hyperopia.

We present a hyperopic patient with a decentered line of sight in whom the residual refractive error after toric phakic intraocular lens (TP IOL) implantation was improved by displacement and individualized treatment. A 35-year-old woman presented with asthenopic complaints 2 months after bilateral TP IOL implantation and IOL rotation 4 weeks later. Examination revealed the line of sight to be nasally and inferiorly decentered in relation to the center of the pupil. A more nasal reenclavation of the TP IOL decreased the coma, and the uncorrected visual acuity was 20/20. We conclude that line of sight should be measured before TP IOL implantation, especially in hyperopic eyes.

Adult↗

PubMed2004

Evaluation of cut quality using the Amadeus microkeratome with different settings.

PURPOSE: To evaluate the quality of keratectomy specimens created with the Amadeus microkeratome (AMO) using scanning electron microscopy (SEM). SETTING: Johannes Gutenberg-University Hospital, Department of Ophthalmology, Mainz, and the Department of Anatomy, Justus Liebig-University, Giessen, Germany. METHODS: Corneal cuts were performed in freshly enucleated pig eyes using the Amadeus microkeratome with 9 combinations of oscillation rate and head-advance speed. For the cutting trials, oscillation rates of 8000, 13,000, and 18,000 rpm and head-advance speeds of 1.0, 2.5, and 4.0 mm/s were chosen. Fifty-four eyes were included, resulting in 9 groups of 6 eyes for each configuration. The surfaces and edges of the flaps were examined using SEM. RESULTS: At fixed oscillation rates, an increase in head-advance speed led to lower quality cuts, higher surface roughness, and irregular cut edges. At fixed head-advance speeds, an increase in oscillation rates improved the cut quality, resulting in smoother surface characteristics. CONCLUSIONS: Smooth and regular surfaces and cut edges can be achieved by choosing high oscillation rates and low head-advance speeds. Microkeratomes that enable the user to adjust the oscillation rate and head-advance speed can be used to maximize surface smoothness and improve customized refractive surgery.

Animals↗

PubMed2004

Contrast sensitivity after implantation of toric iris-claw lenses in phakic eyes.

PURPOSE: To evaluate the change in contrast sensitivity after implantation of the Verisyse toric phakic intraocular lens (IOL) (AMO) for the correction of myopia with astigmatism. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: Eighteen eyes had implantation of an iris-supported toric phakic IOL to correct myopia with astigmatism. The mean preoperative spherical equivalent was -12.65 diopters +/- 3.6 (SD). The contrast sensitivity with best spectacle correction was determined before surgery and 3 months after surgery using the CSV-1000 HGT instrument (Vector Vision Inc.). RESULTS: Three months after IOL implantation, the mean contrast sensitivity had significantly increased from preoperatively at midrange spatial frequencies from 3.2 to 4.4 (6 cycles per degree [cpd]; P = .033) and from 2.4 to 3.7 (12 cpd; P = .032). The differences at spatial frequencies of 3 cpd and 18 cpd were not statistically significant (P = .59 and P = .086, respectively). CONCLUSIONS: Implantation of the Verisyse toric iris-claw lens in phakic eyes to correct high or moderate myopia with astigmatism has the potential to improve contrast vision. The mean contrast sensitivity increased considerably at all spatial frequencies compared with preoperative levels.

Adult↗

PubMed2004

Late postoperative opacification of MemoryLens hydrophilic acrylic intraocular lenses: case series and review.

PURPOSE: To report clinical and spectrographic analyses of 2 explanted hydrophilic acrylic intraocular lenses (IOLs). SETTING: John A. Moran Eye Center, Salt Lake City, Utah, USA, and Johannes Gutenberg-University, Department of Ophthalmology, Mainz, Germany. METHODS: We report 6 cases of opacification of MemoryLens IOLs (Ciba Vision) that occurred approximately 2 years after implantation. The anterior and posterior surfaces of the IOLs had a white, frosted appearance, and the IOLs' interior looked brown, similar to the appearance of a brunescent cataract. Two of the IOLs were explanted because of a significant decrease in visual acuity. The IOLs were sent for further clinicopathologic analysis including scanning electron microscopy and energy dispersive x-ray spectroscopy (EDX). RESULTS: Microscopic analysis revealed multiple, fine, granular deposits of various sizes on the surface of the lens optics. The EDX analysis showed the presence of calcium within the deposits. CONCLUSIONS: Our cases show that hydrophilic acrylic IOLs can opacify even years after implantation. Analysis of the explanted IOLs revealed calcification.

Acrylic Resins↗

PubMed2004

[Laser in situ keratomileusis with a flying-spot excimer laser and a carriazo-barraquer microkeratome - outcomes after 6 months].

PURPOSE: To evaluate safety, efficacy, predictability and refractive stability of LASIK, using a flying-spot excimer laser, 91 eyes were examined during a 6-months follow-up. PATIENTS AND METHODS: Consecutively, 91 eyes were enrolled in the study, each eye previously underwent LASIK with the ESIRIS excimer laser (ESIRIS, supplier: eye-tech-solutions Schwind, Kleinostheim, Germany). 91 myopic eyes (mean preoperative refraction: - 5.4 D, range: - 3 to - 13.3 D, astigmatism: - 1 D, range: 1.3 to 3.5 D) were included. A full ophthalmological examination was performed during the first week, 1, 3 and 6 months postoperatively. RESULTS: 26 % of all eyes achieved an uncorrected visual acuity of 0.8, 35 % of 1.0 and 5 % 1.2 6 months postoperatively. 23 % of the eyes lost 1 line of best spectacle-corrected visual acuity (BSCVA), 25 % gained one or more lines of BSCVA. Refraction of 90 eyes were within +/- 1 D of emmetropia 6 months postoperatively. There was no change in spherical equivalent within the interval of 6 months, all eyes were within +/- 0.5 D. CONCLUSION: LASIK with the ESIRIS excimer laser was an effective and safe option with good stability and predictability within the specified interval.

Adult↗

PubMed2003

Impact of head advance and oscillation rate on the flap parameter: a comparison of two microkeratomes.

PURPOSE: To compare flap quality and thickness in an experimental setting using the Amadeus and Carriazo/Barraquer microkeratomes. METHODS: One hundred and sixty-three fresh porcine cadaver eyes were used to cut corneal flaps. One hundred and thirty-five eyes were cut using the Amadeus microkeratome with various settings of head advance and oscillation rate, 28 eyes using the Carriazo/Barraquer microkeratome (Supratome). Flap diameter and hinge width were measured by planimetry and flap thickness by ultrasound pachymetry. Descriptive statistical analysis was based on medians and quartiles, graphical representation on box plots. The measurement devices were compared by two sample Wilcoxon tests, their deviation from the distributors' reference measurement values by sign tests. RESULTS: Variation of oscillation rate and head advance led to significant differences in flap thickness. Optimal cut quality was achieved with 1 mm/s head advance and 8,000 rpm in the Amadeus microkeratome. With this setting the smallest target deviations in flap thickness were obtained among the results with lowest range (median 170 micro m, interquartile range 18 micro m, target 160 micro m). The Amadeus microkeratome demonstrated a statistically significant lower deviation from the target thickness ( P<0.001) and also a lower range than the Supratome (median 127 micro m, interquartile range 30 micro m, target 140 micro m; P<0.001). CONCLUSIONS: Optimization of microkeratome settings leads to minimized deviation from target thickness and improved parameter. The Amadeus microkeratome achieved a statistically significant lower deviation in flap thickness than the Carriazo/Barraquer microkeratome. Individualization of the microkeratome settings may help to decrease flap complications and improve refractive outcome.

Animals↗

PubMed2003

Comparison of biometric measurements using partial coherence interferometry and applanation ultrasound.

PURPOSE: To compare and contrast axial length (AL) measurements assessed by ultrasound biometry and optical biometry. SETTING: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. METHODS: Optical biometry and ultrasound biometry were performed in 360 eyes to measure AL. RESULTS: In eyes with a clear-appearing crystalline lens, there was a statistically significant median difference in AL measurements between the 2 methods in eyes with a normal or long length. In eyes with cataract, there was a statistically significant median difference in AL measurements in eyes with a normal or short length. In these cases, optical biometry produced larger readings than ultrasound biometry. In eyes with a posterior chamber intraocular lens, there was no statistically significant difference between the 2 methods in eyes of all lengths. In all eyes, the 2 methods produced reliable measurements. CONCLUSIONS: These results show that optical biometry and ultrasound applanation biometry give statistically significant differences in AL measurement in patients with cataract and normal lenses. In these cases, optical biometry provided clinically relevant larger values than ultrasound applanation. Optical biometry provides an alternative to ultrasound biometry. However, ultrasound biometry may be indicated in certain complex cases.

Biometry↗

PubMed2003

Evaluation of the practicality of optical biometry and applanation ultrasound in 253 eyes.

PURPOSE: To evaluate the percentage of eyes that could not be measured using optical biometry and ultrasound applanation and the reasons. SETTING: Department of Ophthalmology, Johannes Gutenberg-University Hospital, Mainz, Germany. METHODS: Optical biometry (IOLMaster, Carl Zeiss Meditec AG) and A-scan ultrasound biometry were performed consecutively in 253 eyes scheduled for cataract surgery the next day. Lens opacities were evaluated with the Opacity Lensmeter (Interzeag), and a slitlamp examination and measurement of visual acuity were performed. The 2 techniques were compared in terms of the rate of and reasons for primary measurement failure. RESULTS: Measurement with the IOLMaster was not possible in 44 eyes (17%). Failed measurements were the result of a combination of low visual acuity and lens opacity in 45% of eyes, posterior subcapsular opacity in 25%, and macular disease in 7%. Measurement with ultrasound biometry was not possible in 10 eyes (4%); 7 eyes were filled with silicone oil and in 3 cases, the patient refused biometry. CONCLUSIONS: Optical biometry allowed comfortable, noncontact, high-precision measurement in the optical axis. Uncorrected visual acuity and lens opacity were predictors of successful measurements. Eyes with dense cataract or poor visual acuity are better evaluated using ultrasound applanation.

Adolescent↗

PubMed2003

Postoperative astigmatism and rotational stability after artisan toric phakic intraocular lens implantation.

PURPOSE: To evaluate deviations in the axis (intended versus achieved) and postoperative astigmatism after implantation of an Artisan toric phakic intraocular lens (IOL). SETTING: University Eye Hospital, Mainz, Germany. METHODS: This prospective study comprised 29 eyes with high ametropia and astigmatism. All eyes had uneventful implantation of a toric phakic IOL through a superior scleral tunnel incision at 12 o'clock. After a minimum of 6 months, the uncorrected visual acuity (UCVA), best correct visual acuity, refraction, and astigmatism were analyzed in all eyes. A multivariate analysis of postoperative astigmatism was performed. RESULTS: After a follow-up of at least 6 months, 95% of eyes were within +/-1.00 diopter (D) of emmetropia and 85% of eyes has a UCVA of 20/30 or better. The difference between the mean intended cylinder axis and achieved cylinder axis was 3.9 degrees (median 3 degrees; range to 13 degrees). The difference between the mean intended axis and the achieved axis between miosis and mydriasis was 1.8 degrees (median 1.5 degrees; range 0 to 5 degrees). The mean postoperative astigmatism after 6 months was 0.56 D with an axis of 31 degrees. Doubled-angle scatterplot analysis showed a tendency toward more flattening in the vertical meridian. CONCLUSIONS: During the 6-month follow-up, no significant rotation was observed after implantation of Artisan toric phakic IOLs to correct high ametropia. A sutureless sclerocorneal superior approach for phakic IOL insertion resulted in moderate to low astigmatism. Induced astigmatism should be taken into consideration during preoperative planning.

Adult↗

PubMed2003

Capsule measuring ring to predict capsular bag diameter and follow its course after foldable intraocular lens implantation.

PURPOSE: To evaluate the extent of capsular bag shrinkage after cataract surgery with intraocular lens (IOL) implantation and develop a regression formula to predict postoperative capsular bag size. SETTING: Eye Hospital, Johannes Gutenberg-University, Mainz, Germany. METHODS: The axial length (AL), anterior chamber depth, and corneal radius in 58 eyes were measured preoperatively. Cataract surgery was by phacoemulsification followed by implantation of a 3-piece, acrylic, posterior chamber IOL. The capsular bag diameter and anterior capsulorhexis were measured intraoperatively and 1 day and 1, 3, and 6 months postoperatively using a Koch capsule measuring ring (HumanOptics). RESULTS: The mean capsular bag size was 10.53 mm intraoperatively, 10.31 mm at 1 day, 9.62 mm at 1 month, 9.07 mm at 3 months, and 9.01 mm at 6 months. The mean capsular bag shrinkage over the entire postoperative period was 14.8% (P<.001). Of the parameters studied, only AL had a positive correlation with capsule shrinkage. The correlation was moderate but statistically significant (P =.001). CONCLUSIONS: A correlation was found between capsular bag shrinkage and AL. Using preoperative biometric data, a regression formula of moderate validity was determined to predict capsular bag shrinkage.

Acrylic Resins↗

PubMed2003

Implantation of a custom intraocular lens with a 30-diopter torus for the correction of high astigmatism after penetrating keratoplasty.

We present a 62-year-old woman who had implantation of an intraocular lens (IOL) with a torus of 30.0 diopters (D) in an eye after penetrating keratoplasty. The patient presented with cataract and a best corrected visual acuity of 20/400. Penetrating keratoplasty was performed in 1975 because of decompensated keratoconus. With a clear but inferiorly decentered corneal graft, visual acuity was limited because of keratoplasty-related high corneal astigmatism of 22.5@156 that could not be successfully treated with spectacles or contact lenses. A custom toric IOL with -30.0 D of cylindrical power was implanted in the capsular bag via a sclerocorneal tunnel incision. Additionally, a spherical IOL of -15.0 D sphere was implanted in the ciliary sulcus. Six months after implantation, the IOLs were still well centered and the uncorrected visual acuity was 20/60.

Astigmatism↗