Refractive outcomes and quality of vision related to an outbreak of diffuse lamellar keratitis

PURPOSE

To report the impact on visual function and corneal aberrations during an epidemic of diffuse lamellar keratitis (DLK).

METHODS

A retrospective, comparative, and consecutive case-control study was performed, involving 418 eyes operated between March and October 2007 in the refractive surgery unit of one center. Eyes were separated into groups: group 1 (DLK group) included 209 eyes that presented with DLK after LASIK and group 2 (control group) included 209 unaffected, consecutive eyes operated from the beginning of the outbreak. Refractive variables and corneal aberrations were compared between the two groups.

RESULTS

Visual outcomes were significantly different when comparing control eyes and eyes with DLK grades 3 and 4, but not for eyes with DLK grades 1 and 2. Uncorrected distance visual acuity (UDVA) significantly improved from the third month after DLK was diagnosed (Kruskal-Wallis, P=.02). Corrected distance visual acuity (CDVA) did not decrease significantly with DLK grades 1 and 2 (preoperative CDVA vs 1, 3, and 6 months after diagnosis; Mann-Whitney, P>.05, respectively). At the end of follow-up, UDVA and CDVA were not significantly different between the two groups. Eyes suffering from DLK had significantly increased corneal aberrations, except for spherical and astigmatism aberrations, 3 months after being diagnosed (Kruskal-Wallis, P<.05); however, corneal aberrations were not significantly different between the DLK and control groups (Mann-Whitney, P>.05).

CONCLUSIONS

The outbreak of DLK did not induce a significant decrease in global visual outcomes, except in severe cases, and postoperative corneal aberrations were not affected.

Visual and optical performance with two different diffractive multifocal intraocular lenses compared to a monofocal lens

PURPOSE

To compare the visual acuity outcomes as well as the ocular optical performance of eyes implanted with either a monofocal or one of two diffractive multifocal intraocular lenses (IOLs).

METHODS

One hundred two consecutive eyes of 51 bilateral cataract patients (age 49 to 80 years) were divided into three groups: 22 eyes were implanted with a monofocal IOL (monofocal group), 40 eyes with the Acrysof ReSTOR SN6AD3 IOL (ReSTOR group), and 40 eyes with the Acri.Lisa 366D IOL (Acri.Lisa group). Visual acuity and contrast sensitivity were evaluated pre- and postoperatively. Additionally, ocular optical quality and intraocular aberrations were evaluated postoperatively.

RESULTS

Significant improvement after surgery in uncorrected and corrected distance and near visual acuity was observed in all three groups (P≤.05). Uncorrected near visual acuity was significantly better in eyes from the ReSTOR and Acri.Lisa groups compared to the monofocal group (P≤.01). Photopic contrast sensitivity was significantly better for the spatial frequency of 3 cycles/degree in the monofocal group (P<.01). Significantly higher values of the ocular Strehl ratio and cutoff modulation transfer function spatial frequency were also found in the Acri.Lisa group (P=.01). An acceptable range of vision between near and distance peaks was observed in the defocus curves of the ReSTOR and Acri.Lisa groups.

CONCLUSIONS

The AcrySof ReSTOR and Acri.Lisa 366D IOLs are able to successfully restore near and intermediate visual function after cataract surgery; however, the Acri.Lisa design seems to provide better optical performance. These results need to be confirmed in a randomized, prospective trial.

Inhibition of corneal neovascularization by topical bevacizumab (Anti-VEGF) and Sunitinib (Anti-VEGF and Anti-PDGF) in an animal model

PURPOSE

To evaluate the effects of topically applied bevacizumab and sunitinib on experimentally induced corneal neovascularization.

DESIGN

Experimental animal study.

METHODS

Thirty-six New Zealand rabbits were involved. One eye per rabbit was used. Corneal neovascularization was induced by placing 5 silk sutures in the upper cornea. Rabbits were randomized to 1 of 3 groups (12 rabbits each): Group 1 received saline 0.9%, Group 2 bevacizumab 5 mg/mL, and Group 3 sunitinib 0.5 mg/mL. All treatments were administered 3 times daily for 14 days. Photographs were taken on a slit lamp on days 7 and 14, and angiographic photographs were taken on day 14. The area of neovascularization was measured in mm(2), percentage of the total corneal area, and percentage of the corneal surface covered by sutures.

RESULTS

On day 14, corneal neovascularization area in Group 1 (25.92 ± 5.08 mm(2), 18.78% ± 3.5% of corneal surface, 105.59% ± 18.9% of corneal surface with sutures) was larger than in Groups 2 (18.52 ± 7.94 mm(2), 13.67% ± 5.8%, 76.35% ± 33.2%) (1-way analysis of variance, P = .041) and 3 (4.57 ± 2.32 mm(2), 3.40% ± 1.7%, 18.94% ± 9.2%)(P < .001). Neovascularization in Group 2 was larger than in Group 3 (P < .001). Compared to saline, corneal neovascularization was inhibited 28.5% by bevacizumab and 82.3% by sunitinib. Sunitinib settled on the iris.

CONCLUSIONS

Topical administration of both bevacizumab and sunitinib inhibits corneal neovascularization in rabbits. But vascular endothelial growth factor (VEGF) pathway blockade by bevacizumab was not sufficient for a profound inhibition. Blocking both VEGF and platelet-derived growth factor pathways using sunitinib was 3-fold more effective.

Increased risk for flap dislocation with perioperative brimonidine use in femtosecond laser in situ keratomileusis

PURPOSE

To determine whether brimonidine 0.2% minimizes the occurrence of subconjunctival hemorrhages without inducing postoperative flap complications in femtosecond laser in situ keratomileusis (LASIK).

SETTING

Centro Oftalmológico Marqués de Sotelo and Hospital NISA Virgen del Consuelo, Valencia, Spain.

METHODS

This prospective contralateral-eye interventional study evaluated consecutive patients who had bilateral simultaneous femtosecond LASIK for myopia (spherical equivalent [SE] range -1.00 to -8.00 diopters) performed with an IntraLase femtosecond laser and a Visx Star 2 excimer laser. One eye of each patient received a single drop of brimonidine tartrate 0.2% (brimonidine group) and the other eye, a single drop of a balanced salt solution (control group).

RESULTS

The study evaluated 136 eyes (68 patients). The difference in the incidence of subconjunctival hemorrhages was statistically significantly lower in the brimonidine group (mean score 2.24 +/- 1.96 [SD]) than in the control group (mean score 7.61 +/- 2.72) (P<.001). However, no eye in the control group and 7 eyes (10.4%) in the brimonidine group had a dislocated flap with folds on the first postoperative day (P = .016). All eyes with dislocated flaps required surgical intervention. At 6 months, there was no significant difference between groups in the percentage of eyes achieving 20/20 or better uncorrected distance visual acuity, in the mean SE, or in the enhancement rate.

CONCLUSIONS

Brimonidine prevented the formation of subconjunctival hemorrhages after femtosecond LASIK but increased the risk for flap dislocation. Thus, surgeons are cautioned against the use of perioperative brimonidine to decrease hemorrhagic complications in femtosecond LASIK.

Femtosecond laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE

To assess the use of the femtosecond laser for laser in situ keratomileusis (LASIK) in eyes with consecutive hyperopia after radial keratotomy (RK).

SETTING

Private ambulatory surgical center, Valencia, Spain.

METHODS

This prospective noncomparative interventional case series study included 13 eyes of 9 patients with secondary hyperopia after previous RK. The patients were operated on with the IntraLase femtosecond laser (IntraLase Corp.) and the Star S2 excimer laser (Visx, Inc.). Postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, flap thickness, flap diameter, and complications were evaluated at 6 months.

RESULTS

The mean spherical equivalent (SE) decreased from 2.00 diopters (D)+/-0.40 (SD) to -0.41+/-0.61 D, with 8 eyes (61.5%) within+/-0.50 D of the targeted refraction. Twelve eyes (92.3%) had a UCVA of 20/40 or better, and 3 eyes (23.1%) lost 1 line of BSCVA. A mean change in SE of 0.10 D was observed at the 6-month follow-up. The mean flap thickness and diameter were 117+/-14 microm and 9.18+/-0.12 mm, respectively. Most complications were in eyes with more than 8 RK incisions than in eyes with 8 RK incisions. These complications were multiple intraoperative incision openings (100% versus 28.6%, respectively), interface inflammation (66.6% versus 0%, respectively), haze (83.3% versus 14.3%, respectively), and loss of BSCVA (50% versus 0%, respectively).

CONCLUSIONS

The femtosecond laser provided large, thin corneal flaps for hyperopic LASIK. However, the procedure should be avoided in eyes with more than 8 RK incisions because of the increased risk for multiple intraoperative incision openings, interface inflammation, haze, and loss of BSCVA.

Confocal Microscopy and Histopathological Examination of Diffuse Lamellar Keratitis in an Experimental Animal Model

PURPOSE

To investigate the cell populations and structural alterations of the cornea in an experimental model of diffuse lamellar keratitis (DLK) using confocal microscopy and histopathology.

METHODS

A corneal flap was cut in 22 eyes of 11 New Zealand rabbits and the stromal interface was exposed to balanced salt solution (BSS, BSS group) and Pseudomonas aeruginosa lipopolysaccharide (LPS) endotoxin (5 mg/mL) (LPS 5 mg/mL group) and (3.5 mg/mL) (LPS 3.5 mg/mL group). Postoperatively, eyes were examined with a slit-lamp microscope (DLK grading) and confocal microscopy. Animals were sacrificed on day 3 (BSS group and LPS 5 mg/mL group) and day 4 (LPS 3.5 mg/mL group). Corneoscleral buttons were excised and processed for histopathologic examination.

RESULTS

Seven eyes were excluded. Slit-lamp microscopy revealed no cellular infiltration in the BSS group (five eyes). In the LPS groups, all eyes developed DLK, with iritis only observed in grade III eyes. In the LPS 5 mg/mL group, four eyes had DLK grade III, with iritis in three eyes. In the LPS 3.5 mg/mL group, three eyes had grade II and three eyes had grade III with iritis. On confocal microscopy, the BSS group had no cellular infiltration. Dense accumulation of inflammatory cells at the interface was noted in both LPS groups. Histopathology in the BSS group had a normal appearance. In the LPS groups, an inflammatory infiltrate was present at the interface that consisted of three cell populations--eosinophils, neutrophils, and lymphocytes.

CONCLUSIONS

Lipopolysaccharide endotoxin induced DLK in all exposed eyes, with iritis in a considerable proportion of eyes. The infiltrate consisted of three cell populations. Confocal microscopy showed the infiltrate in all affected eyes. Histopathological and confocal microscopic findings correlated well with the clinical appearance.

Outcomes of ZB5M Angle-supported Anterior Chamber Phakic Intraocular Lenses at 12 Years

PURPOSE

To evaluate the visual and refractive stability and the potential long-term risks associated with ZB5M phakic intraocular lens (PIOL) implantation.

METHODS

A retrospective, non-randomized, cumulative clinical study was performed over 12 years in a consecutive group of 225 eyes implanted with the ZB5M PIOL. The main analyzed variables were visual and refractive outcomes (best spectacle-corrected visual acuity [BSCVA], uncorrected visual acuity [UCVA], and spherical equivalent), endothelial cell density, and postoperative complications.

RESULTS

Mean preoperative spherical equivalent refraction was -17.23 +/- 7.69 diopters (D) and 12 years postoperatively it was -1.80 +/- 0.80 D. Mean BSCVA at 1- and 12-year follow-up was 0.38 +/- 0.19 and 0.57 +/- 0.18, respectively (Wilcoxon test, P < .001). At 12 years postoperatively, 3.5% of eyes lost > or = 2 lines of BSCVA. An initial 10.6% reduction in endothelial cell density was noted in the first year, followed by a mean annual rate of decrease of 1.78%. The cumulative incidence of pupil ovalization was 34.7% (78 eyes), and there was no statistical correlation with endothelial cell impairment. Bilateral hypertensive uveitis was diagnosed in 3 (1.33%) eyes.

CONCLUSIONS

The ZB5M PIOL offers good refractive outcomes and stability in the long-term; however, endothelial cell loss increases over 12 years, requiring annual endothelial cell counts.

Confocal Microscopy Comparison of IntraLase Femtosecond Laser and Moria M2 Microkeratome in LASIK

PURPOSE

To analyze the quality of LASIK flaps created using a femtosecond laser or a mechanical microkeratome.

METHODS

A prospective study of consecutive bilateral LASIK flaps (100 patients) created with a 15 kHz femtosecond laser (IntraLase) or with a mechanical microkeratome (Moria M2) was performed. Outcome measures included visual and refractive outcomes, flap dimensions, and intraoperative complications. The first consecutive ten patients (20 eyes) were examined using confocal microscopy 1 and 3 months following surgery.

RESULTS

No significant differences were noted in the visual outcomes between groups (t test, P > .05 for all comparisons). Analysis of superficial measurements revealed more round flaps and greater predictability in surface dimensions for the femtosecond laser group (t test, P = .016). Mean deviation of flap thickness from target was the same for both instruments, 10 microm, with greater variability for the mechanical microkeratome. The incidence of diffuse lamellar keratitis was significantly greater in the femtosecond laser group (17%) than in the mechanical group (0%) (chi-square test, P < .001). Confocal microscopy revealed a higher wound healing opacity index in the femtosecond laser group.

CONCLUSIONS

Although the clinical results are similar, the femtosecond laser produces LASIK flaps with more accurate dimensions compared to the mechanical microkeratome.

Transient light-sensitivity syndrome after laser in situ keratomileusis with the femtosecond laser

PURPOSE

To describe the incidence of transient light-sensitivity syndrome (TLSS) after laser in situ keratomileusis (LASIK) with the femtosecond laser and to identify preventive strategies.

SETTING

Hospital NISA Virgen del Consuelo, Valencia, Spain.

METHODS

The first 765 eyes operated on with the 15 KHz femtosecond laser were prospectively analyzed for subjective complaints and clinical findings compatible with TLSS. Intraoperative settings, postoperative treatment, and development of complications were analyzed.

RESULTS

Overall, TLSS developed in 10 eyes (incidence 1.3%). However, the incidence decreased from 2.8% to 0.4% when aggressive topical steroids were used during the first 3 postoperative days. Postoperative interface inflammation and postoperative use of a low-dose topical steroid regimen were associated with a higher incidence of TLSS.

CONCLUSIONS

Transient light-sensitivity syndrome is a relatively uncommon complication related to the use of the femtosecond laser. Postoperative interface inflammation may increase the probability of developing TLSS, whereas an aggressive postoperative steroid regimen seemed to provide protection against it.

Angle-Supported Anterior Chamber Phakic Intraocular Lens ExplantationCauses and Outcome

PURPOSE

To investigate the reasons for explantation of angle-supported phakic intraocular lenses (IOLs) as well as the outcome and safety of the explantation procedure.

DESIGN

Consecutive retrospective series.

PARTICIPANTS

One hundred eyes of 66 patients who underwent phakic angle-supported IOL explantation.

INTERVENTION

Surgical explantation of anterior chamber angle-supported phakic IOLs.

MAIN OUTCOME MEASURES

Visual acuity, refraction, and endothelial cell density.

RESULTS

The main causes of explantation were cataract development (64 cases [64%]), progressive endothelial cell loss (24 cases [24%]), and pupil ovalization (10 cases [10%]). According to the reason for phakic IOL explantation and the condition of the eye at time of explantation, 92 cases underwent bilensectomy (phakic IOL explantation followed by phacoemulsification of the crystalline lens), 2 cases underwent phakic IOL exchange, 4 cases underwent concomitant phakic IOL explantation and penetrating keratoplasty, and 2 cases underwent simple explantation of a phakic IOL. The mean time between phakic anterior chamber IOL implantation and explantation due to cataract was 10.04+/-3.66 years (range, 2-14). The mean time between implantation and secondary intervention due to progressive endothelial cell loss was 8.97+/-2.21 years (range, 2-14), and most of these cases were related to a specific model of angle-supported phakic IOL.

CONCLUSION

Nuclear cataract was the most frequent reason for angle-supported phakic IOL explantation. Bilensectomy was effective and maintained the refractive benefits obtained with phakic IOL implantation. Few cases developed severe endothelial cell loss, most of them related to certain types of phakic IOLs.

Prophylactic Perioperative Antiviral Therapy for LASIK in Patients With Inactive Herpetic Keratitis

PURPOSE

To report the outcome of LASIK in patients with inactive herpetic keratitis in which perioperative antiviral prophylaxis was used to prevent the recurrence of ocular herpes.

METHODS

We report an uncontrolled series of five patients with inactive herpetic keratitis for at least 1 year before surgery in whom LASIK was successfully performed. All patients showed normal topography, pachymetry, and corneal sensitivity with no central corneal scarring. Perioperative prophylaxis was used in each case with oral valacyclovir and topical acyclovir ointment.

RESULTS

None of the eyes developed reactivation of herpetic keratitis during follow-up.

CONCLUSIONS

This study suggests that perioperative antiviral prophylaxis may protect the cornea from herpes simplex virus reactivation after LASIK.

Confocal Microscopy of Disposable and Nondisposable Heads for the Moria M2 Microkeratome

PURPOSE

To study the quality of the flap obtained with two different heads, disposable and nondisposable, and two different speeds, low and high, using the same Moria M2 microkeratome (Moria, Antony, France).

METHODS

In a prospective randomized study, 51 consecutive eyes (28 patients) underwent myopic LASIK (-4.39 +/- 2.15 diopters). The eyes were randomly assigned to four groups related to cutting head model (disposable and nondisposable) and cut speed (low and high). In all cases, the intended cut was 160 microm and the same M2 unit was used. During surgery, superficial measurements of the flap and the surgeon's opinion about the quality of the cut were recorded. One month after LASIK, the cut depth, interface particle density, and transparency of the cornea (confocal wound healing opacity index) were measured with a confocal microscope.

RESULTS

Flaps performed with a disposable cutting head and high speed were statistically significantly larger than the flaps created in the other groups (Kruskal-Wallis test; P = .041). No statistical differences were noted in cut depth, number of particles, and wound healing opacity index. The surgeon's opinion parameters were similar in all groups.

CONCLUSIONS

The Moria M2 microkeratome is safe and provided reproducible results, regardless of cutting head and speed. Disposable and nondisposable head models were similar in their outcome in the quality control model used in this study.

LASIK in Patients with Rheumatic Diseases

PURPOSE

To investigate the safety of LASIK in patients with a known history of controlled rheumatic diseases.

DESIGN

Retrospective consecutive observational clinical study.

PARTICIPANTS

Forty-two eyes (22 patients) known to have had a history of rheumatic diseases underwent LASIK. All patients had a history of controlled rheumatic diseases, including rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, scleroderma, ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease, arthritis, or Behçet's disease.

METHODS

Assessments were made preoperatively and at 1, 3, and 6 months postoperatively and included visual acuity (VA), refraction, keratometric readings, slit-lamp biomicroscopy, and corneal topography. All the patients underwent LASIK. Postoperative treatment included a topical steroid-antibiotic combination.

MAIN OUTCOME MEASURES

Visual acuity, refraction, keratometric readings, and slit-lamp biomicroscopy findings at 1, 3, and 6 months postoperatively.

RESULTS

LASIK was performed uneventfully on all patients. The mean pre-LASIK spherical equivalent (SE) was -5.39+/-2.25, and the sixth month postoperative SE was -0.15+/-0.38 diopters (D) (P<0.001). Uncorrected VA 6 months after the LASIK procedure was 20/25. Enhancement procedures were performed in 6 of 42 eyes (14.3%) at variable times after the primary procedure. Postoperative follow-up showed development of a moderate degree of dry eye syndrome in 4 eyes (9.5%). Corneal haze, melting, flap, or interface complications were not observed in any of the study eyes.

CONCLUSIONS

In this small series, we found good outcomes when correcting refractive errors using LASIK in selected patients with controlled rheumatic diseases. In this series, a favorable postoperative visual outcome was obtained with no operative or postoperative vision-threatening complications.

[Confocal microscopy of the cornea in photorefractive surgery]

OBJECTIVE

Corneal refractive surgery involves a range of techniques which have assumed a growing importance during the last few years. The advances of very different surgical methods and the early age of the majority of the patients subjected to surgery, limits our knowledge of the histopathologic changes in the operated corneas. For this reason, the development of any diagnostic tool which can permit us to improve our knowledge of the wound healing process would be of significant value. As we describe in our paper, confocal microscopy enables the assessment of the more important advantages for the study of corneal wound healing after refractive surgery: high magnification, harmless, and "in vivo", providing pathogenic information and lateral and axial definition not achievable with other exploration techniques.

CONCLUSION

Confocal microscopy appears to be an essential tool for creating a global concept of quality in corneal refractive surgery.

Severe anaphylactic reaction after intracameral antibiotic administration during cataract surgery

We report a severe anaphylactic reaction that occurred about 5 minutes after 1.0 mg of cefuroxime was injected into the anterior chamber after routine phacoemulsification and intraocular lens implantation. The patient was known to be allergic to penicillin. Immediate action was taken, and the patient recovered well. The presence of staff trained in resuscitation was essential in this case and raises questions about the trend to perform routine topical anesthesia cataract surgery without an anesthesiologist in the operating room.

Laser in situ keratomileusis to correct post-keratoplasty astigmatism; 1-step versus 2-step procedure

PURPOSE

To investigate the correction of post-penetrating keratoplasty (PKP) astigmatism using laser in situ keratomileusis (LASIK). Visual and refractive outcomes were evaluated after LASIK was performed in 1 step (lamellar cut and ablation in 1 procedure) or 2 steps (lamellar cut then ablation in 2 successive procedures).

SETTING

Department of Cornea and Refractive Surgery, Vissum-Instituto Oftalmológico de Alicante, University of Miguel Hernández, Alicante, Spain.

METHODS

In this prospective observational study, 22 consecutive eyes were divided into 2 groups depending on the LASIK procedure performed to correct post-PKP astigmatism. Group 1 (1-step LASIK) included 11 eyes and Group 2 (2-step LASIK), 11 eyes. The patients were followed for 6 months.

RESULTS

A statistically significant improvement was obtained in Group 2 with a mean vector analysis result of the cylinder of -4.37 diopters (D) +/- 1.79 (SD) (P = .018). In Group 1, the mean astigmatism correction was 2.38 +/- 1.71 D. The number of reoperations and residual refractive defects were significantly better in Group 2.

CONCLUSION

The 2-step technique improved the accuracy of excimer laser correction of post-PKP astigmatism.

Automated superficial lamellar keratectomy augmented by excimer laser masked PTK in the management of severe superficial corneal opacities

AIM

To assess superficial lamellar keratectomy augmented by excimer laser smoothening with sodium hyaluronate 0.25%, for the management of superficial corneal opacities.

METHODS

Consecutive procedure performed in 14 eyes (13 patients) with an automated microkeratome and excimer laser phototherapeutic keratectomy (PTK) smoothening using sodium hyaluronate 0.25%.

MAIN OUTCOME MEASURES

UCVA, BCVA, pachymetry, degree of haze, ray tracing analysis, and complications. Mean follow up was 12 (SD 1.6) months.

RESULTS

Mean preoperative haze from previous corneal refractive surgeries was 3.5 (SD 0.5) (11/14 cases). In one case, opacity was caused by ocular trauma and in two by infectious keratitis. The mean preoperative UCVA was 0.7 logMAR (0.2 (SD 0.13) decimal value). BCVA was 0.4 logMAR (0.4 (SD 0.17) decimal value). Mean preoperative corneal pachymetry was 508 (SD 62.5) micro m and mean opacity depth measured by corneal confocal microscopy was 115.2 (SD 49.4) micro m. At 6 months, 71.4% of the eyes with previous corneal refractive surgery showed grade I haze or less. Mean postoperative corneal pachymetry at 6 months was 352.36 (SD 49.05) micro m.

CONCLUSIONS

Automated superficial lamellar keratectomy combined with excimer laser PTK smoothening assisted by sodium hyaluronate 0.25% induces a significant improvement of corneal transparency and visual acuity in cases of corneal opacity caused by previous refractive surgery, ocular trauma, and keratitis.

Comparison of Four Corneal Pachymetry Techniques in Corneal Refractive Surgery

PURPOSE

To assess the effectiveness of optical and ultrasonic pachymetry when examining corneas of patients before and after laser in situ keratomileusis (LASIK).

METHODS

We conducted a prospective study of 25 patients (50 eyes) who had LASIK for myopia or myopic astigmatism (mean spherical equivalent refraction -4.80 +/- 3.60 D; range -1.75 to -12.00 D). Corneal thickness was measured using 1) conventional ultrasonic pachymetry (20 MHz probe) in the central cornea, 2) ASL confocal microscopy (CMTF analysis), 3) Orbscan II Analyzer, and 4) ultrasound biomicroscopy (UBM) (50 MHz probe) preoperatively and 3 months postoperatively.

RESULTS

Preoperative pachymetry values measured with the Orbscan II Analyzer (551.3 +/- 27.3 microm) were almost identical to those measured with the 20 MHz ultrasonic probe (553.7 +/- 25.7 microm; t-test P = .652). The mean preoperative pachymetry for UBM was 566.7 +/- 38.8 microm and for CMTF was 553.2 +/- 15.5 microm. The optic and ultrasonic system measurements differed in operated eyes; 20 MHz ultrasonic pachymetry yielded an average 478.7 +/- 23.5 microm and the UBM, 482.4 +/- 40.3 microm. These measurements differed from the Orbscan II (Tukey test; P = .023) measurement of 461.1 +/- 37.5 microm but not from the confocal microscopy measurement of 475.2 +/- 41.8 microm. UBM registered greater values that were more variable than those obtained with ultrasonic pachymetry.

CONCLUSIONS

In non-operated eyes, corneal thickness was similar using conventional ultrasound, Orbscan II, or confocal techniques, with ultrasound biomicroscopy giving thicker readings.

Follicular conjunctivitis caused by Chlamydia trachomatis in an infant Saharan population: molecular and clinical diagnosis

AIMS

To ascertain the prevalence of acute trachoma as a supposed endemic disease among infants in the Saharan refugee camps of Tindouf (Algeria) and to evaluate the efficacy of treatment with a single dose of azithromycin.

METHODS

527 children aged between 3 and 17 were evaluated in the camp schools in October 2001. All the children were clinically and microbiologically examined, including slit lamp checks of anterior segment and two conjunctival swabs, one for the detection of membrane lipopolysaccharide by quick immunoassay test Clearview Chlamydia MF and the other for the detection of specific DNA by chlamydia plasmid specific polymerase chain reaction (PCR) assay. After examination, a single dose of azithromycin was administered to each child. One month later samples from positive children and 12 random negative children by the first PCR were taken to perform a new PCR assay.

RESULTS

Chlamydia trachomatis was suspected in 2.47% of the children, papillary hypertrophy being the most frequently seen clinical sign. Scarring changes secondary to trachoma were detected in 11.7% of the children. Only four cases (0.8%) were positive to the immunoassay test and 12 cases (2.27%) were positive by PCR. After treatment a second PCR was performed on positive children and they were negative of chlamydia DNA amplification. However, one child who was negative and received the treatment was positive in the second PCR assay.

CONCLUSION

Acute trachoma prevalence is much lower than expected among infants in this Saharan population. The possible reasons could be the recent improvements in hygiene and health care. Cicatricial trachoma is more frequent. The Clearview immunoassay test has very low sensitivity in the detection of this disease. A single dose of azithromycin is sufficient to treat chlamydial conjunctivitis. However, a programme of improvement in hygiene and health care is necessary to prevent re-infection.