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Biomedical subjects

Y Lachkar

Publications and source records attributed to Y Lachkar.

At least 19 recordsLinked to original sources
PubMed2006

[Argon laser iridoplasty in the treatment of angle closure glaucoma with plateau iris syndrome].

INTRODUCTION: Plateau iris predisposes to the onset of an angle-closure glaucoma attack without pupillary block. This is a morphological anomaly of the iris characterized by anterior insertion, root thickness greater than the norm, and anterior rotation of the ciliary processes into the posterior chamber, pushing the base of the iris into the angle. Argon laser iridoplasty is useful to retract the peripheral iris using the thermal effect of the laser to widen the iridocorneal angle. MATERIALS AND METHODS: The study investigated nine eyes of five patients who had had iridoplasty for iris plateau angle-closure glaucoma, diagnosed by dynamic gonioscopy (or indentation gonioscopy) and confirmed by ultrasound biomicroscopy (UBM). There were four females and one male, with a mean age of 42.2 years (range, 30-53 years). The mean intraocular pressure (IOP) before iridoplasty was 21.1 mmHg. The number of antiglaucoma treatments was 1 or 2, with all patients receiving miotic treatment. All patients had undergone argon laser iridotomy beforehand to remove the pupillary block frequently associated with iris plateau. Iridoplasty was done in two sessions with postoperative IOP-lowering treatment. The laser parameters used were: duration, 0.3 s; power, 500 mW; diameter, 300 microm. RESULTS: The postoperative IOP evaluated at 1 month was 14.4 mmHg with a reduction in the hypotensive treatment. No treatment was prescribed for four eyes, a single hypotensive treatment for four eyes, and two hypotensive medications for one eye. DISCUSSION: Pure iris plateau syndrome, leading to closure of the angle, is very rare compared to pupillary block, but these two mechanisms often co-exist. The physiopathology explains that the mechanism of isolated iris plateau is not modified by iridectomy. However, the advantage of argon laser iridoplasty, which retracts the periphery of the iris so as to widen the iridocorneal angle, must be emphasized. This technique can alleviate the need for high-risk filtering surgery, but longer follow-up is necessary to evaluate its duration and efficacy.

Adult↗
PubMed2006

[I have tested for you. The contour tonometer. IOP analysis using "Dynamic Contour Tonometry"].

The Pascal tonometer, or the Dynamic Contour Tonometer (DCT) (Swiss Microtechnology, Zurich) is a device that differs from the Goldmann applanation tonometer (GAT) in its IOP sensor at the center of the cone that measures pressure by a means less dependent on corneal structure. The efficacy of this device in measuring IOP after LASIK surgery has been demonstrated. It can be used to obtain more precise IOP measurements in glaucoma patients or ocular hypertension in cases where the measurement is debatable because of a very thin or very thick cornea. We studied the relations between the measurements with the two devices on thin, normal, and thick corneas. The Pascal tonometer generally showed a good correlation with the Goldmann applanation tonometer, but the limits of agreement are wide. For thin corneas, this device seems more reliable than the GAT, but for thick corneas, no difference was found between the two methods.

Cornea↗
PubMed2005

[Surgical controversy. Limiting postoperative scarring].

Postoperative follow-up of glaucoma surgery must be rigorous and carried out over the long term. Data acquired on the make-up of the filtering bleb justifies using postoperative anti-inflammatory drugs, even if the eye is clinically quiet. When using antimetabolites, the risk factors for failure must be well known and either 5-fluorouracile or mitomycin should be chosen depending on the level of risk of scarring. Their use in needle revision must be adapted case by case. anti-TGF-beta-2 antibody, currently being investigated, may prove advantageous in the very near future.

Cicatrix↗
PubMed2004

[Automated imaging of the optic nerve and optic nerve fibers is essential to daily clinical practice].

Chronic open-angle glaucoma is a progressive optical neuropathy. Automated imaging of the optic disc and optic nerve fibers provides reliable analysis of the optic nerve as well as long-term follow-up of neuropathy patients. HRT, GDX-VCC, and OCT, which analyze the optic disc and optical fibers, provide indisputable assistance in improving screening techniques and the follow-up of progressive glaucoma.

Chronic Disease↗
PubMed2003

[Scoring system for chronic open glaucoma].

PURPOSE: The aim of this study was to evaluate a scoring system for chronic open-angle glaucoma. We devised an empirical scoring system grading severity of the disease and correlated this with treatment. MATERIAL: and methods: Ninety patients were evaluated on 11 parameters: 1) Family history of glaucoma: blindness (2), yes (1) no (1); 2) Age: infantile (4), juvenile (4); 3) Race: Caucasian (0), Asian (1), Afro-Caribbean (2); 4) Myopia: 0-6 diopters (1), 6-12 diopters (2),>12 diopters (3); 5) Pigment dispersion or pseudoexfoliation (1); 6) Intraocular pressure without treatment:>30 mmHg (4); 25-30 mmHg (3), 20-25 mmHg (2); 7) Corneal central thickness:<500 micro m (3),>500 micro m (0); 8) Optic disc appearance: suspect (1), pathological (4); 9) Visual field defect: early (1), moderate (3), advanced (5); 10) Vascular risk factors: yes (1), no (0); 11) Loss of eyesight in one eye due to glaucoma (4). Scoring values were 2-34. We correlated this score with patient treatment: medical or surgical, number of glaucoma medications. RESULTS: Patients were divided into three groups: group 1 (36 patients), score 0-8; group 2 (24 patients), score 9-13; group 3 (30 patients), score above 13. Distribution between patients treated with medicine (mean number of medications) and patients with filtering surgery was: group 1, medical treatment with 1.63+/-0.73 medications, surgery 4/36; group 2, medical treatment with 2.00+/-0.7 medications, surgery 17/24 and group 3, medical treatment with 2.12+/-0.67 medications, surgery 27/30. In group 1, 88% of the patients did not have filtering surgery, but 90% of the patients in group 3 had filtering surgery. CONCLUSION: This scoring system seems to be an easy and practical tool to evaluate chronic open-angle glaucoma, which could also be used to evaluate target pressure. Other studies are necessary to validate this scoring system.

Adolescent↗
PubMed2003

[Optic disk drusen: what are the advantages of the new imaging techniques?].

This study reports four clinical cases of papillary drusen associated with OHT. The authors show the advantages of HRT, OCT2, and GDx for exploring the optic nerve and/or the retinal nerve fiber layer (RNFL). The repercussions of drusen on the optic nerve head may precede visual field failure. Better knowledge of the interpretation of these new imaging techniques may help define the respective roles of drusen and OHT, in case of visual field attack, and treatment modalities. These new procedures may help us to monitor drusen and their progression potential.

Adult↗
PubMed2003

[Angle-closure chronic glaucoma].

The incidence of chronic angle closure glaucoma is considerably greater than the incidence of the acute type. This type of glaucoma may mimic primary open angle glaucoma with visual field deterioration, optic nerve alteration and intraocular pressure elevation with a quiet painless eye. Its diagnosis is based on indentation gonioscopy showing peripheral anterior synechiae. The mechanisms of angle closure are the pupillary block, the plateau iris configuration and the creeping form. The treatment of chronic angle closure glaucoma is based on laser peripheral iridotomy.

Chronic Disease↗
PubMed2002

[Non penetrating filtering surgery, evolution and results].

Trabeculectomy is currently the standard filtration procedure for glaucoma surgical treatment. Despite several advantages over full-thickness procedures, trabeculectomy can be responsible for early postoperative complications related to sudden ocular decompression that can lead to hypotony with its sight-threatening complications. Nonpenetrating glaucoma surgeries, namely viscocanalostomy and deep sclerectomy with external trabeculectomy, have been developed in recent years in order to improve the safety of conventional filtering procedures. The goal of these procedures is to reduce intraocular pressure (IOP) by enhancing the natural aqueous outflow channels, while reducing outflow resistance, attributed for 75% to the trabecular meshwork and for 25% to the outer wall of Schlemm's canal (SC) or tissue surrounding it. In these procedures, the anterior chamber is not opened so that complications related to full thickness procedures are mainly avoided. In the last few years, viscocanalostomy and deep sclerectomy with external trabeculectomy have become the most popular nonpenetrating filtering procedures. Both involve the removal of a deep scleral flap, the external wall of SC, and corneal stroma behind the anterior trabecula and Descemet membrane, thus creating a scleral lake. The aqueous humor leaves the anterior chamber through the intact trabeculodescemetic membrane and reaches the scleral lake, from where it will egress into different pathways. In viscocanalostomy, a high-molecular viscoelastic substance is injected into the ostia of the SC in order to enlarge the SC and its collector channels. In deep sclerectomy with external trabeculectomy, the main goal is to remove the inner wall of the SC and the adjacent trabecular layers involved in aqueous outflow resistance, while leaving the innermost trabecular layers intact so that the anterior chamber does not open during operation. Different surgical adjuvants designed to maintain the scleral lake open are commercially available. Retrospective and prospective published studies have reported similar midterm results with trabeculectomy and nonpenetrating filtering procedures in terms of IOP control, with fewer postoperative complications and better visual acuity recovery with the nonpenetrating procedures. This article reviews the current nonpenetrating surgical procedure techniques, their mechanism of action, and their outcome.

Filtering Surgery↗
PubMed1998

Effect of brimonidine tartrate on ocular hemodynamic measurements.

OBJECTIVE: To study the effect of a selective alpha 2-adrenoreceptor agonist, brimonidine tartrate, on ocular hemodynamics. SUBJECTS AND METHODS: Eighteen patients with ocular hypertension were enrolled in a prospective, randomized, double-masked study in which 0.2% brimonidine tartrate, administered twice daily, was compared with its vehicle in a crossover fashion. The effect on the ocular circulation was assessed by color Doppler ultrasound, which measured blood flow velocities (peak systolic and end diastolic velocities) in the central retinal, ophthalmic, nasal, and temporal ciliary arteries. The following tests were performed at 2 weekly intervals on both treatments, 0.2% brimonidine tartrate and the placebo: intraocular pressure, heart rate, blood pressure, and color Doppler ultrasound. RESULTS: Velocities and resistivity indices measured by color Doppler ultrasound in the ophthalmic artery, central retinal artery, nasal artery, and temporal ciliary arteries showed no statistically significant differences between the placebo and 0.2% brimonidine tartrate when compared with baseline values and between the groups. Intraocular pressure was decreased by 17.7% +/- 9.5% with 0.2% brimonidine tartrate (vs 9% +/- 8% with placebo). CONCLUSION: The hemodynamics of the posterior segment of the eye as measured by color Doppler ultrasound do not appear to be altered by 2% brimonidine tartrate.

Adrenergic alpha-Agonists↗
PubMed1998

[Rapid Tendency Oriented Perimeter (TOP) with the Octopus visual field analyzer].

PURPOSE: To study the capabilities of a new perimetric strategy with the Octopus visual field analyzer: the Tendency Oriented Perimetry. METHODS: Tendency oriented perimetry (TOP) attempts to assess the visual field by using answers to questions to establish thresholds in the neighboring area. We evaluated 79 visual fields with the Octopus strategy using the program 32 and the TOP strategy split into the following groups: normal visual field or glaucoma suspects (52), moderately advanced glaucoma (16), advanced glaucoma (11). The following parameters were analyzed for the two strategies studied: examination time, MS (means sensitivity), MD (mean defect), LV (Loss Variance), short term fluctuation (RF) and the number of points with a deficit with different p values: p < 0.5; p < 1; p < 2; p < 5. RESULTS: TOP perimetry showed a significant reduction of exploration time: 11.87 minutes with the Octopus 32 vs 2.49 minutes with the TOP strategy (p < 0.001). There is no significant modification for the other parameters (MD, MS, RF) except for the LV (Loss Variance) for the global analysis and for each separate group. CONCLUSION: The TOP strategy reduces examination time significantly but seems to be less accurate especially for the calculation of the depth of each scotoma in comparison with the standard Octopus 32 perimetry.

Adult↗
PubMed1997

Reproducibility of optic nerve head topographic measurements with the glaucoma-scope.

PURPOSE: Glaucoma is an optic neuropathy in which optic nerve changes are important in diagnosis and progression, because the visual field may remain normal even while the optic nerve is undergoing significant damage. Accurate methods to objectively document the appearance of the optic nerve are necessary. In order for an optic disc imaging system to be clinically useful for detecting change, its reproducibility must be established. METHODS: We measured the reproducibility of duplicate measurements in 59 eyes of 31 consecutive patients, grouped into glaucoma subjects (n = 29) and eyes with glaucoma (n = 30), with the 3.10 OIS Glaucoma-Scope. In order to simulate two visits on one day, sets of three optic disc images were obtained first, followed by a repeat set, and the best disc images of each (chosen by the computer) were compared. RESULTS: The coefficients of variation of duplicate measurements for glaucoma suspects and patients with glaucoma were respectively: vertical cup/disc (c/d) ratio, 6.3% and 3.47%; horizontal c/d ratio, 4.61% and 2.97%; c/d area, 3.29% and 1.37%; cup area, 1.82% and 1.72%; mean position (MP) disc, 13.3% and 10.42%; MP total, 10.1% and 13.2%. For three eyes the examination was not possible (opacification of posterior capsule, miosis). CONCLUSION: These results suggest that the 3.10 version of the OIS Glaucoma-Scope allows reproducible measurements in living eyes.

Adult↗
PubMed1997

Sensitivity and specificity of optic disc variables and analysis of a new variable (MP/D) for glaucoma diagnosis with the Glaucoma-Scope.

AIM: In an attempt to use the quantitative optic disc measurements of the Glaucoma-Scope (OIS Sacramento, CA, USA) to distinguish glaucomatous from normal optic discs, a new variable was investigated, the mean disc corrected for the disc size by dividing by the disc area: MP/D. METHODS: Glaucoma-Scope disc evaluation was performed on 81 eyes of 51 patients split into the following groups based on Humphrey 24-2 visual field and clinical criteria of glaucoma: chronic glaucoma n = 27 (including only early, n = 17, and low tension glaucoma, n = 10), ocular hypertension n = 24, pseudoglaucomatous large discs, n = 12, and normal eyes, n = 18. Classic optic disc variables (the vertical and horizontal c/d ratios, and the c/d area) were compared with the new MP/D index calculating receiver operating characteristic curves. RESULTS: The MP/D ratio was able to identify the glaucomatous eyes more easily than other ratios. Areas under the curves were: 0.91 (MP/D); 0.87 (c/d area); 0.85 (c/d vertical); and 0.80 (c/d horizontal). The MP/D index was also correlated with the mean deviation (r = 0.466; p = 0.001). CONCLUSION: MP/D may prove useful in detecting glaucomatous optic nerve damage and could be an interesting screening tool for primary open angle glaucoma.

Adult↗
PubMed1997

Trabeculectomy with intraoperative sponge 5-fluorouracil in Afro-Caribbeans.

AIM: To study the efficacy and safety of intraoperative 5-fluorouracil (5-FU) in Afro-Caribbean patients. METHODS: The results of trabeculectomy in 18 eyes of 18 Afro-Caribbean patients in whom a sponge soaked in 25 mg/ml solution of 5-FU was applied between Tenon's capsule and sclera for 5 minutes before excision of the trabecula were compared with 16 eyes of 16 Afro-Caribbean patients matched for age, quantity, and duration of preoperative medications, who underwent trabeculectomy without 5-FU. RESULTS: The mean postoperative intraocular pressure (IOP) at 1 month was 15.6 (SD 6.1) mm Hg in the 5-FU group and 18.0 (5.2) mm Hg in the control group (p = 0.15). There was no significant difference in the IOP at 6, 12, 15, 18, and 24 months in the two groups. Success rate at 18 months defined as an IOP less than or equal to 21 mm Hg with no adjunctive medication was 56% in the 5-FU group and 55% in the control group. No major complications were noted in either group. CONCLUSION: Intraoperative sponge 5-FU alone is safe but does not appear to decrease the risk of failure of trabeculectomy in Afro-Caribbeans.

Administration, Topical↗
PubMed1996

[Multifocal implants of 3 optic zones: optical performance and clinical functional results].

PURPOSE: Evaluation of multifocal IOL (three optical zones). METHODS: Twenty patients were implanted. Main outcome measures were: uncorrected and best corrected distance and near acuity, brigthness acuity test, contrast acuity with differents methods: Pelli-Robson Chart, Gradual System, and spatial visual integration (SVI). RESULTS: Uncorrected visual acuity was restored in 94% of cases. Contrast sensitivity was preserved with the Pelli-Robson chart test but a loss of contrast sensitivity was found with the multifocal IOL with the Gradual system and the SVI in comparison with monofocal IOL. CONCLUSION: Multifocal IOL (three optical zones) allows a good restoration of both near and far visual acuity but a decrease in contrast sensitivity was detected.

Adult↗
PubMedDate not supplied

Nerve fiber analysis and optic disc parameters with the glaucoma-scope.

PURPOSE: We evaluated the ability of optic disc parameters and nerve fiber analysis with the Glaucoma-scope to distinguish glaucoma from normal or hypertensive eyes. METHODS: Glaucoma-scope examination was performed on 68 eyes of 44 patients split into following groups based on Humphrey 24-2 visual field and clinical criteria of glaucoma: normal eyes (n = 17), ocular hypertension (n = 19), early glaucoma (n = 17), moderately advanced glaucoma (n = 15). The contour of the juxta papillary nerve fiber layers was measured in the four groups. We also evaluated a global index as the mean disc depth corrected for the disc size by dividing by the disc area (MP/D). RESULTS: We found a statistical difference (p < 0.001) between the four groups with the global index MP/D: normal eyes MP/D = -17.42, hypertensive eyes MP/D = -26.34, early glaucoma MP/D = -82.33, moderately advanced glaucoma MP/D = -99.69. We also found a statistical difference between the first two groups (normal visual field) compared to the two glaucoma groups for the mean fiber layer height in the superior and the inferior quadrant. CONCLUSION: Nerve fiber analysis and optic nerve head index calculated with the Glaucoma-scope could prove to be an interesting tool for glaucoma diagnosis and follow-up.

Adult↗
PubMedDate not supplied

Multicenter evaluation of tendency-oriented perimetry (TOP) using the G1 grid.

PURPOSE: The G1-TOP program is a short automated perimetric strategy which sub-divides the G1 grid of 59 points into four sub-grids. Each point is tested only once, but each patient's response is used to modify that particular point and the surrounding ones from the remaining sub-grids. This study compared the results of the G1-TOP program with the Standard Bracketing strategy. METHODS: Eleven participating institutions provided data from 213 patients (406 eyes). The main group consisted of 284 glaucomas and 55 glaucoma suspects. Other groups included 31 eyes with neurological disorders, 20 with chorioretinal lesions and 16 normal eyes. Mean age was 62.7 +/- 15.4 (range 14-88) years. All subjects had previous perimetric experience and visual acuity better than 0.5. Examination included G1-Standard Bracketing and G1-TOP testing, in interchangeable order, with the Octopus 1-2-3 perimeter. RESULTS: The correlation coefficient for mean defect (MD) was 0.95. Standard error (YX) for MD, square root of loss variance (LV) and individual thresholds were 1.86 dB, 1.29 dB, and 4.72 dB, respectively. Mean sensitivity values were similar (difference 0.04 +/- 1.87 dB) (p>0.05). Mean duration for G1-TOP was 2.19 +/- 0.26 min, while G1-Standard Bracketing took 11.51 +/- 1.52 min (ratio 1/5.1, or a net reduction of 80.4%). The sensitivity of G1-TOP versus G1-Standard Bracketing was: glaucoma 77.1/78.5, glaucoma suspects 38.2/47.3, neurological disorders 87.1/87.1 and chorioretinal lesions 80.0/85.0. CONCLUSIONS: The G1-TOP program gave very similar results to G1-Standard Bracketing in only 20% of the time required by the standard strategy.

Adolescent↗