Uveitis-associated flap edema and lamellar interface fluid collection after LASIK

PURPOSE

To report two cases of corneal pathology associated with anterior uveitis after laser in situ keratomileusis (LASIK).

DESIGN

Observational case report.

METHODS

A 47-year-old man and a 50-year-old woman who experienced vision loss and corneal changes associated with acute anterior uveitis after LASIK were examined.

RESULTS

The 47-year-old man, who had undergone LASIK for low myopia developed an interlamellar fluid pocket at the level of the flap interface, whereas the 50-year-old woman, who underwent LASIK for hyperopia, developed marked flap edema without interface fluid collection.

CONCLUSIONS

These two cases demonstrated acute corneal fluid accumulation associated with episodes of acute anterior uveitis in eyes that had undergone LASIK. Uveitis should be considered a risk factor for vision threatening corneal complications after LASIK.

Laser in situ keratomileusis in a patient with presumed central cloudy corneal dystrophy of Francois

PURPOSE

To report a case of laser in situ keratomileusis (LASIK) surgery performed in a patient with likely central cloudy corneal dystrophy of Francois (CCDF).

DESIGN

Observational case report.

METHODS

A 48-year-old woman with likely CCDF had myopic LASIK to establish monovision. Outcome measures included visual acuity, manifest refraction, and slit-lamp examination.

RESULTS

At 5-year follow-up, the patient had uncorrected visual acuity of 20/100, J1, in the right eye (OD) and 20/20 in the left eye (OS), consistent with monovision correction. Manifest refraction was -1.50 OD and -0.25 OS postoperatively; after retreatment at 1 year for regression, the left eye remained stable over the subsequent 4-year period. Slit-lamp examination revealed no progression of corneal opacities in either eye.

CONCLUSIONS

LASIK may be safe and effective in patients with CCDF. Further observations of a greater number of patients are required to confirm these findings.

The effect of hinge position and depth plate on the rate of recovery of corneal sensation following LASIK

PURPOSE

To evaluate and compare the effect of hinge position and flap thickness on recovery rate of corneal sensation after (LASIK).

DESIGN

Prospective, randomized clinical study.

METHODS

Forty eyes of 40 patients underwent LASIK to correct myopia ranging from -1.00 to -2.50 diopters. Corneal sensitivity was measured preoperatively and each month after surgery until recovery to preoperative level. The nasal-hinged ACS microkeratome (NH) with depth plates of 130 and 160 microm and the superior-hinged Hansatome microkeratome (SH) with depth plates of 160 and 180 microm were used for corneal flap creation. The eyes were divided into four groups according to the hinge position and depth plate (DP): group 1, NH and 130 microm DP; group 2, NH and 160 microm DP; group 3, SH and 160 microm DP; group 4, SH and 180 microm DP.

RESULTS

Corneal sensitivity returned to preoperative level after 3.7 (+/- 0.4), 4.4 (+/- 0.6), 5.4 (+/- 0.8), and 5.8 (+/- 0.9) months, respectively, in groups 1, 2, 3, and 4. Statistically significant differences were found between groups 1 and 2, but not between groups 3 and 4. Corneal sensitivity gradually returned to preoperative levels in all groups. Sensitivity of the hinge area was higher than other areas at every time point.

CONCLUSIONS

The results suggest that after LASIK, hinge position and flap thickness seem to be important factors in the rate of return of corneal sensitivity. A thin flap with a nasally placed hinge is associated with the most rapid recovery of corneal sensitivity.

Predicting time to refractive stability after discontinuation of rigid contact lens wear before refractive surgery

PURPOSE

To determine whether discontinuing rigid contact lenses for 3 weeks is sufficient to achieve refractive stability and if not, to identify factors, including indicators of corneal warpage, that are associated with prolonged corneal instability.

SETTING

University-based refractive surgery practice.

METHODS

Charts of patients seen for refractive surgery consultation from January 1999 to March 2001 were reviewed. Patients with a history of rigid gas-permeable (RGP) contact lens use were identified and instructed to discontinue wearing lenses 3 weeks before the initial examination. Patients were examined at 3-week intervals until a stable refraction was achieved (within +/-0.25 diopter [D] sphere and 0.25 D cylinder with less than 25 degrees of axis orientation). Visual acuity, subjective refraction, and corneal topography were obtained at each visit.

RESULTS

Of 55 eyes of 28 patients, 31 eyes achieved refractive stability by the second visit (early-stability group) and 24 eyes required more than 2 visits to achieve stability (late-stability group). No statistically significant between-group difference was observed in age, sex, refractive cylinder, topographic cylinder, difference between refractive and topographic cylinders, surface regularity index, surface asymmetry index, or spherical equivalent at the initial examination. The number of years of contact lens wear was significantly different between the groups (P = .05).

CONCLUSIONS

The time for contact lens-induced corneal changes to reach a steady state after cessation of lens wear is highly variable. Among the variables examined, including those indicating corneal warpage, the factor that correlated with the required time to refractive stability after discontinuation of RGP wear was the length of time of contact lens use. Patients who are long-term RGP wearers should be counseled that multiple visits will likely be required before a stable refraction is obtained.

The effect of cataract surgery on ocular levels of topical moxifloxacin

PURPOSE

To investigate the effect of cataract surgery on the concentration of moxifloxacin in aqueous and vitreous humor after topical application.

DESIGN

Prospective laboratory intervention using a rabbit model.

METHODS

Following topical administration of 0.5% moxifloxacin, 60 minutes before surgery and immediately post cataract surgery, aqueous and vitreous humor were sampled at 30, 60, and 120 minutes postsurgery. Moxifloxacin concentrations were determined by high-pressure liquid chromatography (HPLC). Mean tissue concentrations obtained in surgical eyes were compared with concentrations obtained in nonsurgical eyes. The potential effectiveness of moxifloxacin in providing prophylaxis against intracameral bacterial inoculation was investigated by comparing antibiotic concentrations to minimum inhibitory concentration (median MIC90) values for Staphylococcus aureus and Staphylococcus epidermidis.

RESULTS

In surgical eyes, mean moxifloxacin concentrations in aqueous were 13.9, 16.2, and 12.2 microg/ml versus 25.3, 32.6, and 15.7 microg/ml in nonoperated eyes at 30, 60, and 120 minutes, respectively. No statistically significant differences were found between surgical and nonsurgical eyes. In surgical eyes, mean moxifloxacin concentrations in vitreous were 66.8, 66.6, and 400.2 ng/ml versus 43.1, 199.8, and 54.4 ng/ml in nonoperated eyes at 30, 60, and 120 minutes, respectively. These differences were not statistically significant.

CONCLUSIONS

There were no statistically significant differences in the penetration of topical moxifloxacin in eyes undergoing cataract surgery compared with unoperated eyes. A multiple-drop schedule of moxifloxacin produced aqueous concentrations that were well above the MICs of even resistant strains of the most common organisms implicated in postcataract surgery endophthalmitis.

Completion rate of continuous curvilinear capsulorhexis in pediatric cataract surgery using different viscoelastic materials

PURPOSE

To determine whether viscoelastic materials with a higher viscosity allow better control of the lens capsule, reducing the rate of incomplete continuous curvilinear capsulorhexis (CCC) during pediatric cataract surgery.

SETTING

Department of Ophthalmology, University of California, San Francisco Medical Center, San Francisco, California, USA.

METHODS

This retrospective study comprised 25 eyes of 18 children who had cataract surgery by 1 surgeon. The type of viscoelastic agent used for the CCC portion of the surgery was obtained from surgical dictations and nursing charts and information on complications during the CCC, from surgical dictations. The patient's age, type of cataract, and intraocular lens placement were also obtained.

RESULTS

A CCC was successfully performed in 7 of 15 eyes (46.7%, mean age 7.6 years) using cohesive Healon (sodium hyaluronate 1%) or dispersive Viscoat (sodium hyaluronate 3%-chondroitin sulfate 4%) viscoelastic material and in 9 of 10 eyes (90%, mean age 6.4 years) using the high-viscosity viscoadaptive agent Healon 5 (sodium hyaluronate 2.3%) (chi square = 4.8900; P<.05). The unsuccessful CCCs in the Healon/Viscoat group were in 2 eyes with mature cataract, 1 eye with posterior polar cataract, 1 eye with posterior subcapsular cataract, and 4 eyes with lamellar cataract. The unsuccessful CCC in the Healon5 group was in 1 eye with mature cataract.

CONCLUSION

The superviscous properties of Healon5 under low turbulence conditions appear to lead to a higher CCC completion rate in children.

A phase III, multicenter, randomized, placebo-controlled clinical trial of topical aminocaproic acid (Caprogel) in the management of traumatic hyphema

OBJECTIVE

To determine the safety and efficacy of topical aminocaproic acid (Caprogel) in the management of traumatic hyphema.

DESIGN

Multicenter, randomized, double-masked, placebo-controlled clinical trial.

PARTICIPANTS

A total of 51 patients participated in this trial (power = 36%, 2-tailed test).

INTERVENTION

Patients presenting with traumatic hyphema were randomly assigned to 5-day treatment with topical aminocaproic acid or a placebo gel. Patients were monitored daily with ocular examination and vital sign testing for the 5 days of treatment and at 24 and 48 hours after treatment. General physical examination and laboratory testing were performed at baseline and day 5.

MAIN OUTCOME MEASURES

The main efficacy variable was the rate of rebleeding. Secondary efficacy variables included time to hyphema clearance, intraocular pressure, time to secondary hemorrhage, and visual acuity. Safety variables included adverse events, vital signs, and laboratory measurements.

RESULTS

Rebleeding occurred in 30% of the placebo group (8 of 27; 95% confidence interval [CI] = 14-50%), versus 8% of the treatment group (2 of 24; 95% CI = 1-27%), for an estimated continuity-corrected difference in percentage of patients with bleeding of 17% (95% CI = -3-38%). Secondary efficacy variables were similar in the groups, except that there was a trend towards more visual improvement in the topical aminocaproic acid group (54%) than in the placebo group (30%) at the last measurement (P = 0.08). Adverse events were similar.

CONCLUSIONS

This study provides evidence that topical aminocaproic acid is safe and demonstrates trends towards reducing the rebleeding rate in the management of traumatic hyphema. However, because the study was terminated before complete enrollment, more definitive recommendations will require a larger trial.

A dual optic accommodating foldable intraocular lens

AIM

To design an accommodating intraocular lens with extended accommodative range that can be adapted to current standard phacoemulsification and endocapsular implantation technique.

METHOD

Ray tracing analysis and lens design; cadaver eye implantation.

RESULTS

Ray tracing analysis indicated that axial movement of an exaggerated converging anterior optic linked by spring loaded haptics to a compensatory static diverging posterior optic produced greater change in conjugation power of the eye compared to axial movement of a single optic lens. A dual optic one piece foldable silicone lens was constructed and implanted via a 4 mm corneal incision into the capsular bag of two cadaver eyes.

CONCLUSION

A dual optic intraocular lens design can increase the optical effect of a given displacement and suggests improvements for accommodating intraocular lenses.

Bilateral diffuse lamellar keratitis following bilateral simultaneous versus sequential laser in situ keratomileusis

AIM

To determine the difference in the incidence of bilateral diffuse lamellar keratitis (DLK) in patients undergoing simultaneous versus sequential laser in situ keratomileusis (LASIK) as an indication of intrinsic risk for inflammation.

METHODS

A retrospective non-comparative case series of 1632 eyes that had undergone bilateral, simultaneous or sequential LASIK between April 1998 and February 2001 at a university based refractive centre by three surgeons. All cases that developed clinically evident DLK were identified and reviewed. In order to identify isolated cases and exclude those caused by environmental factors, when more than one patient in a given session developed DLK, the session was excluded. The main outcome measure was the incidence of unilateral and bilateral isolated, non-epidemic DLK.

RESULTS

Of 1632 eyes, 126 eyes (7.7%) of 107 patients developed at least grade 1 DLK. In six operating sessions, DLK was observed in more than one patient per session, and on this basis 13 patients were excluded. 16 of the 94 remaining patients developed DLK in both eyes (17.0%). Six of 41 patients (14.6%) in the simultaneous group, versus 10 of 53 patients (18.9%) in the sequential group developed bilateral DLK (p >0.5).

CONCLUSION

In isolated, non-epidemic bilateral DLK, a similar incidence was observed regardless of whether the surgery was simultaneous or sequential, suggesting an underlying intrinsic cause for DLK.

Efficacy of transport media use versus direct inoculation of blood agar plates in the microbiologic evaluation of experimental Streptococcus pneumoniae keratitis

PURPOSE

To compare the microbiologic yield of cultures obtained by direct inoculation of blood agar plates (BAP) from corneal ulcer swabbings versus indirect inoculation via transport media in a rabbit model of Streptococcus pneumoniae bacterial keratitis.

METHODS

The corneas of 12 rabbits were inoculated with S. pneumoniae. Keratitis was confirmed 18 hours later. Sampling was performed at four 2.5-hour intervals. At each interval, corneal swabs were directly applied to BAP and placed into transport medium: thioglycollate and Amies medium without charcoal. Swabbings were then subcultured onto BAP at two time points: 2 and 24 hours after collection in transport medium. Plates were evaluated 48 hours later. Organism recovery rates were measured in terms of the number of positive culture plates observed and the bacterial colony counts on each plate.

RESULTS

The rate of positive cultures overall was 69%. The recovery rates were similar for direct inoculation, inoculation via Amies held for 2 hours, and inoculation via Amies held for 24 hours. Direct inoculation yielded fewer colonies than indirect inoculation via Amies held for 24 hours (p = 0.008). Direct inoculation yielded a higher rate of positive cultures than did thioglycollate held for 2 hours (p = 0.004) or 24 hours (p < 0.001). The rate of nonpneumococcal contaminants ranged from 6% of BAP subcultured from thioglycollate held for 24 hours to 28% of directly inoculated BAP.

CONCLUSIONS

Amies medium without charcoal may be used as a transport medium for up to 24 hours in the recovery of S. pneumoniae from corneal ulcers in this rabbit model. Thioglycollate appears to be less effective as a transport medium. Results of this study may justify studies of other transport media and/or other corneal pathogens. Altogether, such studies may provide justification for human clinical trials.

Effect of myopic LASIK on human corneal sensitivity

OBJECTIVE

To evaluate the changes in corneal sensitivity after LASIK for the correction of different degrees of myopia.

DESIGN

Prospective, nonrandomized, comparative self-controlled trial.

PARTICIPANTS

One hundred two myopic eyes of 58 patients were included in this study.

METHODS

The eyes were divided into four groups: group 1, from -0.75 to -3.75 diopters (D); group 2, from -4.00 to -7.75 D; group 3, from -8.00 to -11.75 D; group 4, from -12.00 to -16.00 D. Corneal sensitivity was measured before and 1, 7, 30, 90, 180, 270, and 365 days after surgery or until full recovery.

MAIN OUTCOME MEASURES

The recovery of corneal sensation after LASIK.

RESULTS

Immediately after surgery, the lenticule was found to be completely anesthetic, and the full recovery varied according to the depth of the ablation. Normal levels of corneal sensitivity, but not full recovery, were found after 90 days in groups 1 and 2 and after 180 days in groups 3 and 4. Full recovery of corneal sensitivity was found after 180 days in groups 1 and 2 and after 270 days in groups 3 and 4.

CONCLUSIONS

After LASIK, corneal sensitivity is decreased at the central and paracentral areas for as long as 9 months. The depth of the ablation seems to be an important factor in the temporary decrease of corneal sensitivity and its recovery.

Spontaneous corneal hydrops and perforation in keratoconus and pellucid marginal degeneration

PURPOSE

To report two cases of pellucid marginal degeneration and one case of keratoconus associated with spontaneous corneal hydrops leading either to perforation or imminent perforation, requiring urgent keratoplasty.

METHOD

Retrospective interventional case series of three patients with noninflammatory peripheral corneal degenerations. A retrospective review was done of the clinical courses, surgical interventions, and pathologic specimens, development of spontaneous hydrops, perforation, need for surgical intervention, and final visual outcome.

RESULTS

Two patients with pellucid marginal degeneration and one with keratoconus developed spontaneous hydrops followed by aqueous leakage through markedly thinned anterior stroma. In one case, the leak site was successfully sealed after three separate applications of tissue adhesive, although the remaining two cases required penetrating keratoplasty.

CONCLUSIONS

These cases document the very unusual occurrence of corneal hydrops leading to spontaneous corneal perforation in patients with keratoconus and pellucid marginal degeneration.

Peripheral keratitis associated with erythema elevatum diutinum

PURPOSE

To describe a case of peripheral keratitis associated with erythema elevatum diutinum (EED), an unusual immune-complex-mediated cutaneous vasculitis.

DESIGN

Observational case report.

METHODS

A 25-year-old man who was diagnosed 15 months previously with erythema elevatum diutinum presented with an inflammatory peripheral keratitis of the left eye.

RESULTS

Serologic investigations for systemic disorders associated with vasculitic peripheral ulcerative keratitis were unremarkable. As the sclerokeratitis was thought to represent an ocular extension of the patient's cutaneous vasculitis, dapsone therapy was initiated and resulted in a rapid response of both the cutaneous and the ocular inflammation.

CONCLUSIONS

Erythema elevatum diutinum should be included in the differential diagnosis of vasculitic peripheral keratitis.

Evaluating the human optical system: corneal topography and wavefront analysis

In this article we review three different systems for evaluating the human optical system: placido-disc based corneal topography, scanning slit topography, and wavefront sensors. We briefly describe the principles of each system, and discuss the strengths and weakness. We suspect all three will be used by ophthalmologists in the coming decade.

Phakic intraocular lenses

Because of the potential risks associated with phakic IOL implantation, the current use of these devices is mainly in the treatment of high and extreme myopia which are expected to respond poorly to keratorefractive procedures. Overall, in this setting, the outcomes of phakic IOL implantation have been rather favorable, with significant improvement in uncorrected visual acuity, and tolerable visual symptoms in terms of glare and halo.