Heidelberg Retina Tomograph II Findings ofAcanthamoebaKeratitis

PURPOSE

Heidelberg retina tomograph II (HRTII) examination was performed with cornea module in one patient with Acanthamoeba keratitis (AK) to provide images detailing characteristic findings of the disease.

METHODS

A 34-year-old woman presented with clinical signs and symptoms of AK. HRTII with cornea module was performed and the patient underwent laboratory investigations.

RESULTS

HRTII examination with cornea module revealed numerous 20-26-micro m diameter high-contrast round particles within the corneal epithelium and anterior stroma, resembling Acanthamoeba cysts. Stellate cells as well as ovoid irregular objects, possibly inflammatory cells, trophozoites, altered cysts, or activated keratocytes, were also present in the area of stromal infiltrates. Laboratory investigations confirmed the diagnosis of AK.

CONCLUSIONS

HRTII cornea module can be helpful in the diagnosis of AK by identifying acanthamoeba cyst-like structures in the cornea. This technique also has potential uses in monitoring the efficiency of anti-infective treatment.

Mechanized astigmatic arcuate keratotomy with the Hanna arcitome for astigmatism after keratoplasty

PURPOSE

To report the results of correction of post-keratoplasty astigmatism by arcuate keratotomy performed with the Hanna arcitome (Moria).

SETTING

Service 5, Hôpital des 15-20, Paris VI University, Paris, France.

METHODS

Forty eyes operated on for post-keratoplasty astigmatism using the Hanna arcitome were retrospectively studied. Paired symmetrical arcuate keratotomies were performed on the graft button. Mean follow-up was 10.8 months +/- 11.2 (SD). Outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and subjective refraction. For statistical analysis, visual acuity data were transformed into logMAR units. The refractive data were analyzed using the Alpins method.

RESULTS

By a mean of 10.8 +/- 11.2 months after surgery, the UCVA had improved a mean of 0.28 +/- 0.46 lines, which was significant (P = .013). The BSCVA remained stable. The mean subjective cylinder was 8.84 +/- 3.00 diopters (D) preoperatively and 4.88 +/- 2.50 D postoperatively (P<.001). The changes in postoperative subjective cylinder values correlated with preoperative cylinder values (r(s) = 0.584; P<.0001). The subjective axis was modified by 20 degrees or less in 27 eyes (67.5%). The mean surgically induced astigmatism was 8.07 +/- 3.83 D and the mean correction index, 0.96 +/- 0.46. One microperforation occurred and required suturing. Incisions were off center in 1 case, and 2 patients had an allograft rejection after the procedure.

CONCLUSIONS

Arcuate keratotomy performed with the Hanna arcitome was effective in reducing post-keratoplasty astigmatism. The device enabled safer, easier arcuate incisions than with manual techniques. However, predictability and efficacy could be improved by a more accurate nomogram.

In vivo confocal microscopy in fungal keratitis

BACKGROUND

Fungal keratitis is a major blinding eye disease found throughout the world, particularly in developing countries. Given the recent increase in Fusarium keratitis infections in contact lens wearers owing to contact lens solutions, a warning was recently issued by the Food and Drug Administration, making it a public health concern in developed countries.

OBJECTIVE

To show the advantages of in vivo confocal microscopy imaging using the Heidelberg Retina Tomograph II-Rostock Cornea Module (HRTII-RCM) in the early diagnosis of fungal keratitis.

METHODS

HRTII-RCM confocal microscopy was performed on five patients presenting with fungal keratitis and on three donor corneas contaminated with Fusarium solani, Aspergillus fumigatus and Candida albicans.

RESULTS

Direct microscopic evaluation of corneal smears and culture revealed the presence of F solani in four cases and C albicans in one case. HRTII-RCM examination of the infected patients and contaminated donor corneas revealed numerous high-contrast elements resembling Fusarium, Aspergillus hyphae or Candida pseudofilaments in the anterior stroma.

CONCLUSION

HRTII-RCM in vivo confocal microscopy is a new, non-invasive and rapid technique for the early diagnosis of fungal keratitis, showing high-resolution images resembling fungal structures in the early phase of the disease.

[I have tested for you. Pachymetry devices]

Different techniques are currently available to measure central corneal thickness: optical pachymetry, ultrasound pachymetry, optical coherence pachymetry, slit-scanning pachymetry, specular microscopy, and confocal microscopy. Ultrasound pachymetry is the gold standard. It is a noncontact and rapid technique with high precision, approximately 1%. The correlation between optical coherence pachymetry and ultrasound pachymetry is high, with a 0.99 correlation coefficient. Nevertheless, optical coherence pachymetry measurements seem underestimated compared to ultrasound pachymetry measurements. Correlation of ultrasound pachymetry with the other techniques is less satisfying. If the ultrasound probe can be decontaminated for each patient, ultrasound pachymetry seems to be the best technique for measuring central corneal thickness. Otherwise, optical coherence pachymetry seems to be the most advantageous technique.

Intérêt de l’auto-réfractomètre et de l’orbscan pour la mesure du diamètre pupillaire

PURPOSE

We compared pupil size measurements obtained with the Orbscan and autorefractometer to the Colvard Infrared pupillometer in order to determine their respective clinical advantages.

MATERIAL AND METHODS

We prospectively measured the pupil diameter in 94 eyes of 47 normal patients using the Colvard device, the Nikon NKR 8000 autorefractometer, and the Orbscan device. For each device, two successive measurements were taken to determine its reproducibility. We also studied the relationship with the contralateral eye (i.e., difference and correlation). The measurements obtained with the different devices in different light intensities were compared and studied using regression analysis.

RESULTS

Pupil diameter measured using the Orbscan had the highest reproducibility (mean difference between the two successive measurements: 3.8% or 0.15mm) and showed the smallest difference between the two eyes (5.0% or 0.19mm) and the strongest correlation with the contralateral eye (r=0.93; p<0.001). Scotopic Colvard measurements and autorefractometer measurements with low light settings were not significantly different (5.86mm versus 5.86mm; p=0.48). Autorefractometer measurements with low light settings showed the strongest correlation with the scotopic Colvard measurements (r=0.84; p<0.001). The Orbscan measurements were less correlated with the scotopic or photopic Colvard measurements (r=0.73; p<0.001 and r=0.51; p=0.003, respectively). For the Colvard pupillometer, the correlation between photopic measurements and scotopic measurements was also poor (r=0.51; p<0.001).

CONCLUSION

Pupil size measurements with the autorefractometer may be advantageous before refractive surgery. Measuring pupil size in photopic conditions, as with the Orbscan, cannot screen people with large pupils in mesopic conditions.

Étude biométrique du cristallin par échographie A et Orbscan

PURPOSE

To analyze the lens biometry obtained by Orbscan and A-scan ultrasound in normal eyes.

MATERIAL

and methods: The lens thickness obtained by A-scan ultrasound and the anterior curvature of the crystalline lens obtained by Orbscan were prospectively recorded in 280 normal eyes (including eyes with ametropia) of 140 patients (10-95 years of age). The correlation of lens biometry with the contralateral measure, patient age and sex, subjective refraction, and other ocular biometric parameters (anterior chamber depth, iridocorneal angle, corneal diameter, central pachymetry, pupil, corneal radii of curvature, and posterior segment length) was assessed.

RESULTS

The lens anterior curvature showed no significant correlation in particular with the subjective spherical equivalent; however, the quality of this measure was poor: the reproducibility of the lens anterior curvature was low (the average difference between two successive Orbscan measurements was 14.4%). The correlation with the contralateral eye was poor (rs=0.55; p<0.001 versus rs=0.97; p<0.001 for lens thickness). Lens thickness showed the strongest correlation with the patient's age (rs=0.82; p<0.001); it increased by 0.26 mm per decade. Lens thickness correlated with anterior chamber depth (rs=-0.72; p<0.001) and iridocorneal angle (rs=-0.65; p<0.001). The last two parameters also correlated with age (rs=-0.68; p<0.001 and rs=-0.62; p<0.001, respectively). Anterior chamber depth and iridocorneal angle decreased by -0.21 mm and -1.7 degrees , respectively, per decade.

CONCLUSION

Lens thickness is mainly influenced by age and correlates with the anterior chamber depth and the iridocorneal angle. The influence of aging on anterior segment biometry essentially consists in an increase in lens volume.

[Ocular biometry using Orbscan]

Orbscan is a recent optical device that combines the Placido disk of the videokeratoscope and a scanning slit. The scanning slit measures the elevation of both the corneal surface (anterior and posterior) and the anterior iris-lens surface. Biometric measures of the anterior segment such as corneal thickness, anterior chamber depth, corneal diameter, and iridocorneal angle are obtained using spatial coordinates of various ocular surfaces. Orbscan is not only a corneal topograph but a versatile device capable of measuring the biometry of the anterior segment of the eye.

Decreased Corneal Sensitivity in Patients with Dry Eye

PURPOSE

To explore changes in corneal sensitivity that develop in patients with dry eye and the relationship between sensibility and severity of the dry eye disease.

METHODS

Experiments were performed in 44 patients with dry eye and 42 healthy individuals. Corneal sensitivity was measured with the Belmonte noncontact gas esthesiometer. Mechanical (air jets at flow rates from 0 to 200 mL/min, reaching the corneal surface at 34 degrees C), thermal (cold or warm air at subthreshold flow rates changing corneal basal temperature +/-1 degrees C), and chemical stimuli (air containing 0% to 50% CO2 at subthreshold flow rate and temperature at the cornea of 34 degrees C) were applied to the center of the cornea to determine the sensitivity threshold for each stimulus modality. The clinical state of the ocular surface was also explored, measuring the fluorescein tear break-up time, the degree of corneal staining with fluorescein and Lissamine green, and tear production with the Schirmer test.

RESULTS

Both in control subjects and patients with dry eye, the corneal thresholds for mechanical, chemical, and thermal stimulation increased with age. Moreover, the thresholds for the three modalities of stimuli were significantly higher in patients with dry eye than in control subjects. In both groups, individual mechanical, chemical, and thermal thresholds correlated significantly. Also, high thresholds in patients with dry eye correlated with the intensity of fluorescein and Lissamine green corneal staining but not with the results of the Schirmer test.

CONCLUSIONS

Patients with dry eye exhibit corneal hypoesthesia after mechanical, thermal, and chemical stimulation that appears to be related to damage to the corneal sensory innervation.

[Clinical aspects of corneal burns]

Clinical aspects and prognosis of corneal burns mainly depend on the agent responsible for the trauma. The most severe burns are caustic burns, which should be classified as burns caused by basic agents, associated with deep and prolonged injuries, and burns caused by acidic agents, associated with more superficial injuries. At the acute stage, caustic burns induce epithelial defects, corneal edema, and ischemic necrosis of the limbus, conjunctiva, iris and ciliary body. At the early stage, reepithelialization occurs and is often associated with corneal vascularization and stromal infiltrates, followed by corneal scar formation. At the chronic stage, the following complications are possible: corneal scars, limbal stem cell insufficiency, lachrymal insufficiency, irregular astigmatism, ocular surface fibrosis, cataract, glaucoma, decreased intraocular pressure, and ocular atrophy. The Ropper-Hall classification is based on the extent of limbal ischemia. Thermal burns induce epithelial defects at the acute stage, with the more severe forms giving the same complications as caustic burns. Radiation-related burns can be caused by ultraviolet radiations (acute epithelial keratitis, pterygium, droplet-like keratitis), microwaves, infrared radiations, ionizing radiations or, laser radiations. Electrical burns are often a result of torture and give corneal stroma opacification.

Étude de la dilatation pupillaire par l’insert ophtalmique Mydriasert®

PURPOSE

To evaluate the tolerance and efficiency of the Mydriasert(R) ophthalmic insert on pupil dilation.

METHOD

Two pharmaceutical forms of a combination of tropicamide and phenylephrine (HCl) were compared on both eyes of 80 patients. For each patient, one Mydriasert insert (Ioltech) was placed in the lower conjunctival sac of the eye. Dilation of the control eye was obtained using 0.5% tropicamide eye drops and 10% phenylephrine eye drops (Novartis Ophthalmics), which were instilled with three frequency regimens (5, 10 or 15 min). The pupil diameter was regularly measured until the maximal mydriasis had occurred.

RESULTS

Both subjective and objective tolerance of the insert was excellent. The size of the maximal mydriasis obtained when using the insert was significantly greater than that obtained when using the eye drops, regardless of the frequency of the instillation (p < 0.04). The difference in maximal pupil diameter ranged from +0.16 mm to +0.38 mm. Mydriasis kinetics was slower with the insert. The time necessary to obtain a maximal mydriasis was 47.3 min when the insert was used, whereas it was in the range of 31.4 to 38.5 minutes with the eye drops (p < 0.001). As far as pupil diameter is concerned, the superiority of the insert compared to the eye drops became observable only about 45 min after the insert had been placed in the eye. The relative efficacy of the insert compared to the eye drops did not correlate with patient features (p > or = 0.06).

CONCLUSION

Despite the small quantity of drug delivered by the insert, Mydriasert allows a much greater mydriasis compared to that usually obtained when the eye drops were used. However, a longer time lapse is necessary for this to occur.

[Amniotic membrane transplantation for the treatment severe acanthamoeba keratitis]

BACKGROUND

It is now possible to treat ocular surface disorders by means of amniotic membrane transplantation. We performed a study to determine the efficacy of this technique in the treatment of severe Acanthamoeba keratitis.

METHODS

We studied six patients with severe, painful, nonhealing Acanthamoeba keratitis who underwent one or two amniotic membrane transplantation procedures between February 2001 and January 2003. Histopathological analysis of the corneal buttons was performed in four cases.

RESULTS

Eight amniotic membrane transplantation procedures were performed. The mean length of follow-up was 14 (range 3-21) months. The mean interval between institution of medical treatment and the procedure was 3.6 months. All patients had progressive stromal lesions caused by an inflammatory reaction. Complete reepithelialization occurred in four cases, and partial healing in two cases. Ocular inflammation and tissue destruction were decreased in all cases, pain was lessened in five cases, and corneal neovascularization was decreased in four cases. No postoperative complications were observed. Amniotic membrane was observed under dysplastic corneal epithelium on histologic examination.

INTERPRETATION

Amniotic membrane transplantation may be a safe and effective treatment of severe Acanthamoeba keratitis, particularly during the inflammation phase. It may permit penetrating keratoplasty to be delayed.

Le segment antérieur de l’œil des diabétiques

OBJECTIVE

To study the damage to the anterior segment of the eye during mellitus diabetes.

METHODS

We prospectively studied the anterior segment of the eye in 200 diabetic patients and 200 patients with no history of diabetes (control group). Parameters included the corneal curvature radius, corneal thickness, central corneal sensitivity (Cochet Bonnet esthesiometer), pupil diameter before and after dilation using tropicamide and phenylephrine eye drops, delay for maximal pupil dilation, lens transparency, and intraocular pressure. The damage to the anterior segment was compared in both groups and was correlated with the parameters of diabetes (type, duration, and equilibration), retinopathy grade, and peripheral neuropathy.

RESULTS

Corneal geometry (i.e., curvature radius and thickness) and intraocular pressure did not correlate with diabetes. Cataract was significantly influenced by diabetes (p<0.001). The duration needed to obtain pharmacological maximal mydriasis significantly correlated with iris color (rs=0.47, p<0.001), patient age (rs=0.28, p<0.001) and diabetes (rs=0.25, p<0.001). Dilation was significantly longer in the diabetic patient than in those of the control group (36.5 min vs 30.7 min, p<0.001). Corneal sensitivity significantly correlated with age (rs=0.48, p<0.001) and diabetes (rs=0.53, p<0.001). Corneal sensitivity was decreased in the diabetic group (5.42 vs 5.94, p<0.001) and it correlated with retinopathy grade (rs=0.47, p<0.001) and with peripheral neuropathy (rs=0.15, p<0.001). Sensitivity and specificity of hypoesthesia in detecting peripheral neuropathy were 67.4% and 49.4%, respectively. Among the parameters of diabetes, duration of progression showed the strongest correlation with damage to anterior segment (rs > or = 0.25, p<0.001).

CONCLUSION

Diabetes influences lens transparency, pharmacological pupil dilatation and corneal sensitivity. In spite of the unspecific character of the damage and the subjectivity of the measurement, corneal sensitivity is an interesting parameter to take into consideration among diabetic patients.

Relation entre le kératocône et la myopie axile

PURPOSE

To study the relationship between keratoconus and axial myopia.

METHODS

We prospectively studied refraction and ocular biometry in 100 consecutive keratoconus eyes, and 100 emmetropic eyes. Biometric data (including posterior segment length) were obtained by A-scan ultrasound, Orbscan, and ultrasonic pachymetry. Biometric measurements were compared in both groups.

RESULTS

Anterior chamber depth, posterior segment length and axial length were significantly different between the two groups (p<0.001). Axial length was significantly greater in the keratoconus group than in the emmetropic group (23.97 mm versus 23.21 mm, p<0.001). Posterior segment length was significantly greater in the keratoconus group than in the emmetropic group (16.54 mm versus 15.99 mm, p<0.001). In the keratoconus group, the posterior segment length and the subjective spherical equivalent were significantly correlated (rs=-0.45, p<0.001).

CONCLUSION

The increase in posterior segment length in the keratoconus group and the correlation between posterior segment length and spherical equivalent in the keratoconus group suggest a statistical relationship between keratoconus and axial myopia.

Corneal keloid

A 70-year-old man was referred to us with a 2-year, progressive, painless decrease in visual acuity in the right eye. Ocular history included extraction of a traumatic cataract with a transclerally fixated posterior chamber intraocular lens. Slitlamp examination showed a raised, white, vascularized mass covering the cornea. The lesion was removed by superficial lamellar keratectomy. Light microscopy examination confirmed the diagnosis of corneal keloid. These uncommon lesions usually develop in adults after corneal traumas, surgery, or inflammatory processes. They have also been described in children with Lowe's syndrome, Rubinstein-Taybi syndrome, and other ocular developmental disorders.

Analyse biométrique par Orbscan et échographie du glaucome aigu par fermeture de l’angle

PURPOSE

To study acute-angle-closure glaucoma (AACG) biometry using Orbscan and echography.

MATERIAL AND METHODS

We prospectively studied 200 normal eyes of 100 patients (including eyes with ametropia), 50 eyes of 25 patients before peripherial YAG laser iridotomy, 25 phakic eyes of 25 patients with a history of acute-angle-closure glaucoma (AACG) in the fellow eye. Both plane and polynomial modes of reconstruction of the iridocorneal angle measurement were analyzed. Biometric measurements of the three groups were compared. Biometric measurements (i.e., iridocorneal angle, anterior chamber depth, axial length, and lens thickness) and subjective spherical equivalent were correlated with the etiological classification.

RESULTS

Age, sex, iridocorneal angle, anterior chamber depth, lens thickness, axial length and subjective spherical equivalent were significantly different in the three groups (p<0.002). The polynomial iridocorneal angle measurement was 43.4 degrees in the normal group, 36.5 degrees in the iridotomy group, and 28.4 degrees in the AACG group (p<0.001). Iridocorneal angle measurement correlated with the other biometric measurements (rs>0.51; p<0.001) and with the etiological classification (rs< or =0.68; p<0.001). The anterior chamber depth measurement obtained by Orbscan or echography was the best parameter for predicting ACCG (rs=0.77; p<0.001).

CONCLUSION

The anterior chamber depth and polynimial iridocorneal angle obtained using the Orbscan device appears to be useful in predicting acute-angle-closure glaucoma.

[Posterior subcapsular cataract in a case of ulcerative colitis treated with corticosteroid enema]

We report the case of a 65-year-old patient suffering from a long-term ulcerative colitis treated with corticosteroid enema and presenting a bilateral posterior subcapsular cataract. As far as we know, this is the first case report of steroid-induced cataract after intrarectal corticosteroid use. Alternative hypotheses concerning the mechanism of cataract formation are suggested. This case report should warn ophthalmologists and gastroenterologists about the cataractogenic effects of corticosteroid enema to ensure that information is provided for patients suffering from ulcerative colitis.

[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.

Bacterial keratitis: predisposing factors, clinical and microbiological review of 300 cases

AIM

To identify predisposing factors and to define clinical and microbiological characteristics of bacterial keratitis in current practice.

METHODS

A retrospective analysis of the hospital records of patients presenting with bacterial keratitis and treated at the Quinze-Vingts National Center of Ophthalmology, Paris, France, was performed during a 20 month period. A bacterial keratitis was defined as a suppurative corneal infiltrate and overlying epithelial defect associated with presence of bacteria on corneal scraping and/or that was cured with antibiotic therapy. Risk factors, clinical and microbiological data were collected.

RESULTS

300 cases (291 patients) of presumed bacterial keratitis were included. Potential predisposing factors, usually multiple, were identified in 90.6% of cases. Contact lens wear was the main risk factor (50.3%). Trauma or a history of keratopathy was found in 15% and 21% of cases, respectively. An organism was identified in 201 eyes (68%). 83% of the infections involved Gram positive bacteria, 17% involved Gram negative bacteria, and 2% were polymicrobial. Gram negative bacteria were associated with severe anterior chamber inflammation (p=0.004), as well as greater surface of infiltrates (p=0.01). 99% of ulcers resolved with treatment, but only 60% of patients had visual acuity better than the level at admission, and 5% had very poor visual outcome.

CONCLUSIONS

Contact lens wear is the most important risk factor. Most community acquired bacterial ulcers resolve with appropriate treatment.

[Immunosuppression in corneal transplantation]

Rejection is the leading cause of corneal graft failure, induced by loss of the so-called eye immune privilege. Prevention of graft rejection with immunosuppressive therapy is then necessary. Topical corticosteroids are currently the gold standard, and steroids are the only treatment for acute rejection episodes. Steroids are nonspecific immunosuppressive agents, and they can induce glaucoma, cataract, infections, and epithelial defects. Cyclosporin has a specific effect, because it inhibits interleukin-2 transcription and, consequently, the specific activation of T lymphocytes. When cyclosporin is given orally, it effectively prevents graft rejection in high-risk recipients, but it may induce severe side effects (i.e., systemic hypertension, kidney deficiency, and malignant tumor induction). When cyclosporin is given topically, it can effectively replace steroids in case of dexamethasone-induced glaucoma and graft infection, but it can also induce serious corneal epithelial defects. Cyclosporin is not a treatment for acute rejection episodes. Mycophenolate mofetil and FK 506 are promising drugs, but currently they cannot be used routinely to prevent corneal graft rejection.

[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.

[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.

Characterization and functionality of CXCR4 chemokine receptor and SDF-1 in human corneal fibroblasts

PURPOSE

The aim of this study was to investigate whether cultured human corneal fibroblasts express functional chemokine CXCR4 receptors on their cell surface and to determine the presence of its specific ligand, SDF-1 (CXCL12), in human corneal fibroblasts.

METHODS

Human corneal fibroblast cultures were obtained using human donor corneas. CXCR4 receptors were characterized using binding studies and autoradiography with [125I]SDF-1. The functionality of CXCR4 receptors was assessed by intracellular calcium measurement using a dynamic imaging microscopy system. CXCR4 and SDF-1 mRNA were detected in human corneal fibroblasts using reverse transcriptase polymerase chain reaction (RT-PCR). The CXCR4 protein was detected by western blot analysis.

RESULTS

[125I]SDF-1 specifically bound to cultured corneal fibroblasts with a KD value of 8.3+/-1.2 nM. The presence of CXCR4 was confirmed by autoradiography of the radioligand on slices of corneal stroma. SDF-1 induced a rapid and transient intracellular calcium increase in cultured corneal fibroblasts that was blocked by the specific antagonist bicyclam. Moreover, a 48 kDa protein was detected by western blot analysis of corneal fibroblast extracts, using a specific CXCR4 polyclonal antibody. RT-PCR showed the expression of both CXCR4 and SDF-1 mRNAs in human corneal fibroblasts.

CONCLUSIONS

These results indicate for the first time that cultured human corneal fibroblasts express the chemokine receptors CXCR4 and its ligand SDF-1. This latter might exert physiological effects on the cornea and could be involved in pathological conditions such as corneal angiogenesis.