Biomedical subjects

C Allouch

Publications and source records attributed to C Allouch.

16 recordsLinked to original sources

PubMed2003

[Long-term refractive and topographic changes after penetrating keratoplasty].

PURPOSE: To analyze long-term refractive and videokeratoscopic changes after penetrating keratoplasty. PATIENTS AND METHODS: Forty eyes of 40 patients (26 keratoconus) with a clear corneal graft and no other ocular disease were examined after all sutures were removed, respectively at 22.0+/-7.3 months and 50.5+/-13.6 months after keratoplasty. All of the eyes were examined using videokeratography (EyeSys 2000) and ultrasonic pachymetry. Changes in subjective refraction, best spectacle-corrected visual acuity (LogMAR units), topography, and central corneal thickness between both exams were recorded. RESULTS: Visual acuity increased by an average of 0.41 lines +/-0.24 (p<0.001) between both exams, whereas no significant change in refractive astigmatism and videokeratoscopy (i.e., power, pattern, and indices) was observed. Central corneal thickness significantly increased from 545+/-36 micro m to 574+/-40 micro m (p<0.001). Change in best spectacle-corrected visual acuity significantly correlated with delay between the exams (r(s)=+0.34, p=0.03), whereas change in refractive astigmatism, topographic indices, and topographic patterns did not significantly correlate with delay. CONCLUSION: After penetrating keratoplasty, visual acuity improves long after surgery, whereas refraction and corneal surface regularity show no significant modification. This improvement in visual acuity, not explained by current techniques, may be due to an increase in graft transparency.

Adolescent↗

PubMed2003

[Correlation between refraction and ocular biometry].

PURPOSE: To study the correlation between subjective refraction and biometry obtained by Orbscan and echography in normal eyes. To compare biometric parameters with the subjective spherical equivalent. MATERIAL AND METHODS: Subjective refraction, biometric parameters using Orbscan, and echography were recorded in 190 normal eyes (including eyes with ametropia) of 95 patients. Biometric parameters (i.e., corneal diameter, anterior chamber depth, central pachymetry, iridocorneal angle, corneal and lens radii of curvature, and axial length of the eye) were compared in different refractive groups and were correlated with the subjective refraction. RESULTS: Corneal biometric parameters did not correlate with the subjective spherical equivalent and showed no differences between the refractive groups except for the central pachymetry. In the high myopic group (<-6D), the central cornea was significantly thinner (531 micro m versus 549 micro m, p=0.016). The correlation between corneal radius and axial length was strong in emmetropic eyes (r(s)=0.63, p<0.001) and poor but significant in ametropic eyes (r(s)=0.28, p=0.002). Axial length, anterior chamber depth, and iridocorneal angle showed significant differences between the refractive groups (p<0.001) and correlated with the subjective spherical equivalent (r(s[[/INF=0.44, p<0.001). Subjective spherical equivalent showed the strongest correlation with the axial length (rs)=0.82, p<0.001). Subjective spherical equivalent, central corneal thickness, axial length, anterior chamber depth, and anterior corneal radius showed a strong correlation between both eyes (rs[[/INF=0.94, p<0.001). CONCLUSION: Biometric characteristics of the eye (excluding cornea characteristics) vary with subjective spherical equivalent. Axial length presents the strongest correlation with the subjective spherical equivalent and correlates with the other ocular biometric parameters. Axial length plays a major role in the ocular biometry and refraction.

Adult↗

PubMed2003

[Incidence and factors influencing glaucoma after penetrating keratoplasty].

PURPOSE: To determine the incidence and factors influencing glaucoma following penetrating keratoplasty. MATERIAL AND METHOD: We prospectively studied 440 consecutive patients undergoing penetrating keratoplasty over a period of 5 years, with an average follow-up of 2 years. High intraocular pressure was defined as IOP over 20 mmHg measured by Goldmann applanation for at least 1 week or if a patient required topical treatment for at least 1 week. Before surgery, 18.7% of the patients presented with glaucoma or high intraocular pressure; 44.9% received a graft for a bullous keratopathy condition, 25.6% had keratoconus, 31.5% received an anterior chamber lens, and 48.5% were phakic. RESULTS: After surgery, 42.2% of the patients had ocular pressure at 20 mmHg or more and required treatment for high ocular pressure. The increase in intraocular pressure appeared after an average delay of 3.3 +/- 4.7 months. The frequency of the increase in intraocular pressure was 54.3% for the bullous keratopathy patients, 26.6% for the keratoconus patients (p<0.001). At the end of the second year, the graft survival was 82.1% in absence of glaucoma, whereas it was 71.5% in cases of glaucoma after keratoplasty. Between all parameters that we studied, high intraocular pressure before surgery, etiology, the status, and receiver age over 60 years were the main factors influencing high intraocular pressure after keratoplasty. Intraocular pressure was correlated with the decrease in endothelial cell density and was at the origin of graft failure. Intraocular pressure correlated with the Best Spectacle Corrected Visual Acuity (BSCVA) by its effect on endothelial cell density and optic nerve destruction. CONCLUSION: The increase in intraocular pressure is a real and serious complication of keratoplasty. Its physiopathology is very complex. Better knowledge of risk factors can be useful in controlling it.

Adolescent↗

PubMed2003

[Treatment of the sequelae of ocular burns using limbal transplantation].

PURPOSE: To report the results of limbal transplantation in patients with severe ocular burns and limbal stem cell deficiency. PATIENTS AND METHODS: This series includes six autografts (unilateral ocular burns) and five allografts (bilateral ocular burns) performed in ten eyes of ten males with an average age of 43 years. The origin of the ocular burn was chemical in eight cases and thermal in the remaining two cases. The average time between the initial trauma and limbal transplantation was 79 months. The average size of limbal grafts was 190 degrees (range: 80-20 degrees for autografts and 120-360 degrees for allografts). Patients with allografts received oral cyclosporine in three cases, topical cyclosporine in one case, and intravenous methylprednisolone in one case. Eight patients underwent penetrating keratoplasty an average of 11 months after limbal transplantation (range: 5-24 months). RESULTS: The average follow-up time was 36 months (range: 7-77 months). The overall success rate of limbal transplantation (ocular surface improvement) was 73% (8/11). The success rate of penetrating keratoplasty was 63% (5/8). The average initial visual acuity was 0.4/10 and the average final visual acuity was 1.6/10. Visual acuity improved by two lines or more in seven cases. DISCUSSION: Limbal transplantation is a useful surgical technique in patients with severe ocular burns. However, results remain insufficient and new techniques such as limbal stem cell culture and transplantation are needed to improve the visual prognosis of these patients.

Adult↗

PubMed2002

Down's syndrome screening with nuchal translucency at 12(+0)-14(+0) weeks and maternal serum markers at 14(+1)-17(+0) weeks: a prospective study.

BACKGROUND: Sonographic and biochemical methods for Down's syndrome screening have developed simultaneously, but independently. As a consequence, the rate of invasive procedures for fetal karyotyping has dramatically increased and become an important public health issue which needs to be controlled. One approach is to combine sonographic and biochemical results into a single risk assessment. METHODS: In a multicentre interventional study, nuchal translucency (NT) was measured between 12(+0) and 14(+0) weeks of gestation. Maternal serum markers (MSM) were measured between 14(+1) and 17(+0) weeks of gestation. Karyotyping was advised when: (i) NT was > or =3 mm; or (ii) the MSM-related risk was > or =1 in 250 at term. Karyotyping was delayed until after a maternal blood sample had been taken. NT and MSM were expressed as multiples of the medians (MoMs), and risks were calculated and tailored to the study population. A combined risk for NT and MSM was estimated retrospectively. Costs per case diagnosed, and the cost per case averted were calculated for the three screening strategies. RESULTS: A total of 9444 women was screened. Twenty-one fetuses (0.22%) had Down's syndrome, whilst 326 women (3.4%) were lost to follow-up. Among 9118 women followed up, 5506 had both NT and MSM, 821 had only NT, and 2791 had only MSM. Median maternal age was 30.5 years. False-positive rates for NT, MSM and NT combined with MSM were 3.0, 5.8 and 0.23% respectively. The false-positive rate generated by a sequential two-stage screening was 8.6%. Detection rates of Down's syndrome were 62 and 55% for NT and MSM respectively. Seven cases with Down's syndrome (35%) had raised NT and MSM, and 17 (81%) had either raised NT, MSM, or both. For a 5% false-positive rate, detection rates were 55 and 80% for NT alone and for combined NT and MSM respectively. Ultrasound alone appears to be more cost-effective ( pound50 per case diagnosed) than both tests ( pound61 per case diagnosed). CONCLUSIONS: The study results suggest a 25% increase in the detection rate of Down's syndrome using a combination of NT measurement at 12(+0)-14(+0) weeks and MSM at 14(+1)-17(+0) weeks for a 5% false-positive rate, with modest increase in cost.

Biomarkers↗

PubMed2002

[Orbscan: a new device for iridocorneal angle measurement].

PURPOSE: To evaluate the accuracy and reproducibility of iridocorneal angle measurement obtained with a slit-lamp method (Orbscan). METHODS: The iridocorneal angle was measured in 100 normal eyes of 50 patients using the Orbscan II device. Angles were measured in eight meridians using both the "plane" and "polynomial" modes. For each eye, two exams were taken successively and the reproducibility was calculated by analyzing the difference between both measurements. Angle value was correlated with subjective spherical equivalent and other biometric measurements obtained by Orbscan (i.e., anterior chamber depth, axial length, corneal diameter). RESULTS: Reproducibility of the angle measurement was significantly better with the plane mode than with the polynomial mode (5.4%+/-4.7 versus 7.2%+/-6.2; p<0.001). Reproducibility significantly varied with localization (p<0.001). Significant differences were found between reconstruction modes (49.3 degrees +/-4.6 degrees for plane mode versus 42.8 degrees +/-6.7 degrees for the polynomial mode; p<0.001) and according to localization (p=0.02). Correlation with the other biometric measurements was higher for the plane mode than for the polynomial mode. Angle measurement with the plane mode showed significant correlation with subjective spherical equivalent (r(s)=-0.59; p<0.001), the anterior chamber depth measurement (r(s)=-0.74; p<0.001), the axial length measurement (r(s)=-0.34; p<0.002), and the corneal diameter measurement (r(s)=-0.34; p<0.002). CONCLUSION: The iridocorneal angle measure obtained with the plane mode showed high reproducibility and it significantly correlated with clinical parameters. It appears to be useful for clinical application.

Adolescent↗

PubMed2002

[Amniotic membrane transplantation in severe corneal epithelial diseases. Preliminary results].

PURPOSE: To evaluate amniotic membrane transplantation (AMT) in severe corneal epithelial diseases. METHODS: Amniotic membrane transplantation was performed in 14 eyes of 14 patients from four groups: A, five severe ocular burns; B, four cases of cicatricial keratoconjunctivitis; C, three persistent epithelial defects after penetrating keratoplasty; D, two cases of pseudophakic bullous keratopathy. Five patients underwent AMT alone; two patients underwent AMT combined with limbal transplantation; the other three patients had limbal transplantation performed before AMT. Eight patients required combined penetrating keratoplasty. Patients with corneal stable reepithelialization, no corneal neovascularization, and no recurrence of the initial pathology were considered successful. RESULTS: The mean follow-up was 7+/-3 months. All but three patients underwent corneal reepithelialization within 6 weeks of AMT, with a mean healing time of 31+/-23 days. The success rate was 75% at 6 months (Kaplan-Meier method). Three of four procedures in group B failed. In eight patients, visual acuity improved, in one it worsened, and in the last five patients it remained unchanged. Visual acuity increased by an average of 7+/-9 lines. CONCLUSION: AMT is a useful technique for ocular surface reconstruction, especially in association with limbal transplantation. It could also improve the prognosis of penetrating keratoplasty in patients with severe corneal conditions.

Adolescent↗

PubMed2001

[Correlation between corneal topography and subjective refraction in idiopathic and surgery-induced astigmatism].

PURPOSE: To study the correlation between subjective refraction and corneal topography. To compare the topographic analysis of surgically induced astigmatism (cataract and penetrating keratoplasty) with that of idiopathic astigmatism. METHODS: Subjective astigmatism, subjective spherical equivalent, best spectacle-corrected visual acuity (LogMAR units), and videokeratoscopy using the EyeSys 2000((R)) device (axial, tangential, and refractive power) were recorded in 100 eyes with idiopathic astigmatism, 100 eyes after cataract surgery, and 100 eyes after penetrating keratoplasty. Topographies were classified according to pattern (Bogan classification) and asphericity (shape factor: prolate or oblate). RESULTS: The asphericity shape distribution was significantly different between the 3 groups (p<0.001). The shape of idiopathic astigmatism was almost always prolate (90%) whereas the oblate shape was more frequent in the penetrating keratoplasty group (75%). There was no significant difference in topographic pattern distribution between the 3 groups (p=0.11). The asymmetric bow tie pattern was the most common topographic pattern. Topography pattern classification was significantly correlated with the subjective astigmatic cylinder. (r(s)=0.60, p<0.001). Unlike the round and oval patterns, the bow tie pattern was associated with the high subjective cylinder. Correlation between the subjective cylinder, the refractive power cylinder, and the axial power cylinder was strong (r(s)=0.92 p<0.001), but it was weak for the tangential power cylinder (r(s)=0.72 p<0.001). The correlation between the subjective spherical equivalent and central cornea power was poor (r(s)<0.37, p<0.001). Subjective astigmatic cylinder showed the strongest correlation with best spectacle-corrected visual acuity (r(s)=0.70, p<0.001), whereas the predicted corneal acuity, corneal uniformity index, asphericity, and refractive power symmetry index were poorly correlated with it (r(s)<0.54, p<0.001). CONCLUSION: Despite the difference in the asphericity shape, the topographic pattern was similar in the 3 groups. The pattern type was significantly correlated with the subjective astigmatic cylinder. Topographic indices failed to predict visual acuity, while the subjective cylinder showed a strong correlation with visual acuity.

Astigmatism↗

PubMed2001

[Change in refraction and topography after penetrating keratoplasty suture removal].

PURPOSE: To study the refractive and topographic modifications induced by penetrating keratoplasty suture removal. METHODS: We prospectively studied 80 corneas from 80 patients who had undergone penetrating keratoplasty. All of the eyes were examined before and after all sutures were removed, respectively at 10.9 5.1 months and 21.5 9.6 months after keratoplasty. Subjective refraction, best spectacle-corrected visual acuity (LogMAR units), keratometry, and corneal topography using the EyeSys 2000((R)) device (axial tangential and refractive power) were recorded. Topographies were classified according to the pattern (Bogan classification) and the asphericity shape (prolate and oblate). RESULTS: Best spectacle-corrected visual acuity (Log MAR units) increased significantly after suture removal (1.1 1.9 lines, plt; 0.001). Suture removal decreased the subjective cylinder (5.01 D 2.06 with suture, 4.11 2.08 without suture; p=0.009). The change in subjective cylinder correlated with the change in topographic pattern(s)=0.67 p<0.001). Conversely to the "bow tie" patterns, the other topographic patterns were more frequent after suture removal. The change in visual acuity was essentially explained by the change in subjective cylinder(s)=0.40 p=0.002). The average central corneal power decreased significantly after suture removal by 0.83 to 1.81 D (p<0.001), whereas the subjective spherical equivalent increased (hyperopization) (-4.07D 3.73 with suture, -3.48 3.40 without suture; p=0.02). The change in central corneal power significantly correlated with the change in subjective spherical equivalent (r(s)()>0.30 plt; 0.001). The corneal power of the mid-periphery did not significantly change after suture removal. Suture removal significantly modified the asphericity shape distribution. (majority of prolate shape with suture, majority of oblate shape without suture, p<0.001). CONCLUSION: Keratoplasty sutures induce a central bulge in the corneal graft. Suture removal induces a decrease in the subjective cylinder and it increases the subjective spherical equivalent (hyperopization) through a decrease in the central corneal power. Suture removal modifies the corneal topographic pattern and shape. Visual acuity improvement after suture removal is mainly explained by the decrease in subjective astigmatism.

Adolescent↗

PubMed2001

[Ocular biometric measurements with a slit-lamp method (Orbscan)].

PURPOSE: To evaluate the accuracy and reproducibility of the biometric measurements obtained with the Orbscan((R)) device in normal eyes. METHODS: Anterior chamber depth, axial length, and corneal diameter were studied in 50 normal eyes of 25 patients using the Orbscan((R)) device and A-Scan ultrasonography. For each eye, two exams were done successively and reproducibility was calculated by analyzing the difference between both measurements. RESULTS: The reproducibility of anterior chamber depth and corneal diameter measurements obtained by Orbscan((R)) was high (respectively 0.721.25% and 0.831.40%). The anterior chamber depth measurements by Orbscan((R)) and A-Scan ultrasonography were strongly correlated (rs=0.92;p<0.001). The axial length measurement obtained with the Orbscan((R)) device was less reproducible (3.554.11%). For the axial length, the Orbscan((R)) measurements and A-Scan ultrasonography measurement was poorly correlated. (rs=0.64; p<0.001). CONCLUSION: The anterior chamber depth measurement obtained with the Orbscan((R)) device showed high reproducibility and it was strongly correlated with the measurement obtained by A-Scan ultrasonography. Axial length measurement obtained with the Orbscan((R)) device was less reproducible and poorly correlated with the A-Scan ultrasonography measurement. It was not relevant for clinical application.

Adult↗

PubMed2001

[Precision and reliability of Orbscan and ultrasonic pachymetry].

PURPOSE: To compare the accuracy and reproducibility of the orbscan pachymetry and ultrasonic pachymetry in the normal eye and in the penetrating keratoplasty eye. METHODS: Pachymetric measurements were assessed in 50 eyes of 25 normal patients and 50 eyes of 48 patients who had undergone penetrating keratoplasty using both Orbscan II and ultrasonic pachymetry (Tomey SP-2000). For each eye, 2 successive measures were recorded with both instruments. For both devices, the default setting was used. Orbscan pachymetry maps were divided into 5 groups using a modification of Liu's classification. RESULTS: Orbscan pachymetry strongly correlated with ultrasonic pachymetry (rs = 0.91; p < 0.001). Ultrasonic pachymetry values and Orbscan pachymetry values showed no significant differences in the normal group (respectively, 557 microns +/- 36 and 555 microns +/- 34; p > 0.05). Ultrasonic pachymetry values and orbscan pachymetry values were significantly different in the penetrating keratoplasty group (respectively, 571 microns +/- 52 and 550 microns +/- 54; p < 0.001). The best value for the acoustic factor for Orbscan pachymetry in the penetrating keratoplasty group was 0.89. Ultrasonic pachymetry reproducibility and Orbscan pachymetry reproducibility were not significantly different (0.86% +/- 0.61 v. 0.67% +/- 0.63; p = 0.13 in the normal group; 1.22% +/- 0.81 v. 1.23% +/- 1.13; p = 0.92, in the penetrating keratoplasty group). Both pachymetry methods showed less reproducibility in the penetrating keratoplasty group than in the normal group (p < 0.02). Thinnest point localization was significantly different in both groups (p < 0.001). In 66% of the normal group, the thinnest point of the cornea was located in inferotemporal quadrant. This point was located at an average of 0.63 +/- 0.25 mm from the visual axis in the normal group and 1.60 +/- 0.81 mm in the penetrating keratoplasty group (p < 0.001). Whereas "Centered round" (40%) and "centered oval" (34%) were the most common patterns in the normal group, "decentered oval" (40%) and "irregular" (30%) were more frequent in the penetrating keratoplasty group (p < 0.001). CONCLUSION: Orbscan pachymetry strongly correlated with ultrasonic pachymetry. Reproducibility of both methods is excellent and not significantly different. Thinnest point localization and pachymetric map classification are significantly different in normal eyes and in penetrating keratoplasty eyes.

Child↗

PubMed2000

Optical coherence tomography of idiopathic macular epiretinal membranes before and after surgery.

PURPOSE: To examine the preoperative and postoperative anatomical features of the macula using optical coherence tomography in patients who underwent surgery for epiretinal membrane and to correlate these features with functional results. METHODS: In a noncomparative interventional series, 62 eyes of 62 consecutive patients operated on for an idiopathic epiretinal membrane were followed up using a standardized protocol. Preoperative and postoperative examination included best-corrected visual acuity using an Early Treatment Diabetic Retinopathy Study chart, biomicroscopy of the fundus with a contact lens, fundus photography with blue and green filters, fluorescein angiography, and optical coherence tomography. RESULTS: Median preoperative visual acuity was 20/60 (range, 20/32 to 20/320). Median postoperative visual acuity was 20/40 (range, 20/20 to 20/160). Fifty-one eyes (82%) obtained visual acuity of 20/50 or better. Preoperatively, all eyes had increased macular thickness (mean, 419 +/- 105 microm; range, 265.5 to 689 microm), with disappearance of the foveal pit. An epiretinal membrane was visible on optical coherence tomography scans in 26 cases (42%). Intraretinal cystic spaces were present in the thickened macular tissue in 15 cases but corresponded to cystoid macular edema on fluorescein angiography in only three. Postoperatively, mean macular thickness decreased to 300 +/- 65 microm (range, 185 to 511 microm) but returned to normal in only three eyes. The foveal pit reappeared in 20 eyes. Preoperatively, visual acuity correlated with macular thickness (r = 0.56, P <.0001), but not postoperatively (r = 0.12, P =.37). CONCLUSION: Macular thickness decreases after epiretinal membrane surgery, but the macular profile rarely returns to normal. However, this does not preclude satisfactory improvement of visual acuity.

Aged↗

PubMed1999

The results of successful penetrating keratoplasty using donor organ-cultured corneal tissue.

BACKGROUND: The aim of this study was identification of predictive factors for postoperative visual acuity in patients with a clear organ-cultured graft and to analyze the change in visual acuity between 12 and 24 months after transplantation. METHODS: The study design was a prospective cohort study. A total of 342 consecutive penetrating keratoplasties using donor organ-cultured grafts, performed in 324 patients, were included. Visual acuity, graft thickness, and graft endothelial cell density were recorded in patients with clear transplants. RESULTS: At 24 months postoperatively, 25 (18.7%) of 134 patients had 20/200 or worse visual acuity and 66 (49.3%) had 20/40 or better visual acuity. Graft thickness took 1 month to decrease to normal values. A temporary graft thinning occurred at 6 months postoperatively, followed by recovery of normal graft thickness by 18 months. The average postoperative endothelial cell density was 1,533+/-598 cells/mm2 during the second year. The 24-month LogMAR (logarithm of minimal angle of resolution) visual acuity correlated with preoperative LogMAR visual acuity (beta=0.26, P=0.005), postoperative lens status (beta=-0.34, P=0.008), preoperative intraocular pressure (beta=0.50, P=0.020), and postoperative astigmatism (beta=0.17, P=0.040). Visual acuity (P=0.022) significantly improved between 12 and 24 months. Preoperative diagnosis (P < 0.0001) and postoperative lens status (P < 0.0001) significantly influenced the change in LogMAR visual acuity between 12 and 24 months. CONCLUSIONS: Donor variables do not influence the visual acuity results of penetrating keratoplasty using organ-cultured donor tissue, whereas they have a strong influence on graft survival and graft endothelial cell density. Visual acuity improves during the first 2 years after transplantation. After keratoplasty, organ-cultured corneal grafts undergo dramatic modifications of their thickness and probably of their transparency.

Cornea↗

PubMed1999

Effects of penetrating keratoplasty suture removal on corneal topography and refraction.

PURPOSE: To study the refractive and topographic modifications induced by penetrating keratoplasty suture removal. METHODS: We retrospectively studied 50 corneas from 50 patients who had undergone penetrating keratoplasty. All of the eyes were examined before and after all sutures were removed at 10.8+/-4.7 months and 20.3+/-7.9 months after keratoplasty. Subjective refraction, best spectacle-corrected visual acuity (LogMAR units), and corneal topography (EyeSys 2000R device) were recorded. RESULTS: Suture removal decreased the subjective cylinder by an average of 0.91+/-2.32 D (p = 0.004) and modified the corneal topographic pattern (p = 0.03) and shape (p < 0.001) distribution. The change in subjective cylinder correlated with the variation of the steepest meridian power (r(s) = 0.46; p < 0.001). It correlated with the change in topographic pattern (r(s) = 0.59; p < 0.001). The subjective spherical equivalent increased (hyperopization) by an average of 0.61+/-2.24 D (p = 0.01). After suture removal, the prolate shape was less frequent, and the oblate shape was more frequent than before suture removal. Best spectacle-corrected visual acuity increased by an average of 0.8+/-2.0 lines (p = 0.004). The change in subjective cylinder correlated with the change in visual acuity (r(s) = 0.36; p = 0.006). CONCLUSION: Suture removal modifies the corneal topographic pattern and shape. It decreases the subjective cylinder and induces an hyperopization. Visual-acuity improvement after suture removal mainly is explained by the decrease in astigmatism. Suture removal seems particularly helpful in corneas with a bow-tie pattern.

Adolescent↗

PubMed1999

[Effect of sodium hyaluronate administered at the end of penetrating keratoplasty on reepithelialization of the graft].

PURPOSE: To investigate the effect of sodium hyaluronate on reepithelialization time after penetrating keratoplaty. METHODS: We prospectly studied 56 consecutive penetrating keratoplasties. One group of patients (n = 22) received dexamethasone ointment at the end of surgery. The second group (n = 34) received sodium hyaluronate and topical dexamethasone. Postoperative reepithelialization time and graft central thickness were recorded. RESULTS: There was no statistical difference between both groups for epithelialization (4.6 + 3.2 days in the hyaluronate group and 4.4 + 2.3 days in the dexamathasone group) and for graft thickness at day one (710 + 85 microns for the former group and 713 + 84 microns for the latter group) and at day of reepithelialization (663 + 80 microns for the former group and 703 + 99 microns for the latter group). The epithelium aspect was different at the first postoperative day between both groups. CONCLUSION: The use of sodium hyaluronate at the end of penetrating keratoplasty improves the graft epithelium aspect at the first postoperative day, but it does not influence reepithelialization time. Further studies are needed to investigate the mechanism of sodium hyaluronate effect on corneal epithelium.

Aged↗

PubMed1999

[Comparison of EyeSys videokeratoscope algorithms in the evaluation of idiopathic and postoperative astigmatism].

PURPOSE: To compare the accuracy and reproducibility of the Eye Sys videokeratoscope algorithms for analyzing idiopathic and surgery-induced astigmatism analysis. METHODS: Refractive astigmatism, videokeratoscopy (axial, tangential and refractive power), autorefractometry, autokeratometry, and keratometry were recorded in 20 patients with idiopathic astigmatism, 40 patients who had undergone cataract surgery and 40 patients who had undergone penetrating keratoplasty. For each eye, 2 successive videokeratoscopy were recorded. RESULTS: Both cylinder and axis provided by the tangential algorithm are significantly less reproducible than the cylinder and axis provided by the axial and refractive algorithms (P < 0.001). Cylinders provided by the axial and refractive algorithms showed a stronger correlation with subjective cylinder (rs > 0.89; p < 0.001) than the cylinder provided by the tangential algorithm (rs = 0.66; p < 0.001). Both keratometric axis and autokeratometric axis showed the strongest correlation with subjective axis (rs > 0.92; p < 0.001). The accuracy and reproducibility were higher for the topographic "bow tie" patterns than for the other topographic patterns. CONCLUSION: The axial and refractive algorithms of the Eye Sys videokeratoscope are more accurate and reproducible than the tangential algorithm for analyzing idiopathic or surgery-induced astigmatism.

Algorithms↗