Calculating the surgically induced refractive change following ocular surgery

Calculating the surgically induced refractive change following ocular surgery is important for evaluating the results of keratore-fractive procedures, smaller incisions and various wound closures for cataract surgery, and the effect of suturing techniques and suture removal following corneal transplant surgery. We present a ten-step method of calculating the spherical- and cylindrical-induced refractive change in a manner suitable for a programmable calculator or personal computer. Several applications are given including (1) adding the overrefraction to the spectacle correction, (2) determining the surgically induced refractive change from the preoperative and postoperative refractions, (3) determining the surgically induced refractive change from the K-readings, (4) rotating axes, (5) determining the power at meridians oblique to the principal meridians of a spherocylinder, (6) determining the coupling ratio, and (7) averaging axes. Standard methods for calculating and reporting aggregate results are also given.

Inflammatory reaction and capillary leak syndrome related to cardiopulmonary bypass in neonates undergoing cardiac operations

We studied the inflammatory reaction related to cardiopulmonary bypass in 24 neonates (median age 6 days) undergoing the arterial switch operation for simple transposition of the great arteries, with respect to the development of postoperative capillary leak syndrome. Complement proteins, leukocyte count, tumor necrosis factor-alpha, and histamine levels were determined before, during, and after cardiopulmonary bypass. Additionally, protein movement from the intravascular into the extravascular space during cardiopulmonary bypass was assessed by the measurement of plasma concentrations of proteins with molecular weights ranging from 21,200 to 718,000. Capillary leak syndrome developed in 13 of the 24 neonates. Patients with capillary leak syndrome, as compared with those without, had preoperatively higher C5a levels (C5a, 3.0 +/- 0.6 microgram/L vs 0.9 +/- 0.2 microgram/L) (mean +/- standard error of the mean) (p < 0.05) and higher leukocyte counts (leukocytes, 17.9 +/- 2.1 X 10(3) cells/ml versus 11.7 +/- 0.8 X 10(3) cells/ml) (p < 0.05), suggesting in these neonates a preoperative inflammatory state. Preoperative clinical and operative data were identical in both patient groups. Before cardiopulmonary bypass, serum protein concentrations were similar in all patients. Ten minutes after institution of cardiopulmonary bypass, protein concentrations fell to significantly lower values in patients with capillary leak syndrome than in those without: albumin (19% +/- 1.5% vs 30% +/- 6% of the prebypass value, p < 0.05), immunoglobulin G (17% +/- 1.5% vs 29% +/- 5.5%, p < 0.001), and alpha 2-macroglobulin (15% +/- 1.2% vs 25% +/- 4%, p < 0.02). During cardiopulmonary bypass, albumin concentrations remained significantly lower in patients with capillary leak syndrome than in those without, whereas hematocrit values were similar in both groups. During cardiopulmonary bypass, patients with capillary leak syndrome also had lower concentrations of complement proteins C3 and C4 but not C1 inhibitor. C3d/C3 ratio and C5a levels were similar in both patient groups. In contrast, histamine liberation during cardiopulmonary bypass was significantly more pronounced in patients with capillary leak syndrome than in those without (725.2 +/- 396.7 pg/ml vs -54.1 +/- 58.4 pg/ml, p < 0.05). Tumor necrosis factor-alpha levels after protamine administration were also significantly higher in patients with capillary leak syndrome (38.1 +/- 10.0 pg/ml vs 15.3 +/- 3.4 pg/ml, p < 0.05). Leukocyte count during and after cardiopulmonary bypass was similar in both patient groups. This study demonstrates increased protein leakage as early as 10 minutes after initiation of.

Olefin metathesis in supercritical carbon dioxide

Liquid or supercritical carbon dioxide (scCO(2)) is a versatile reaction medium for ring-opening metathesis polymerization (ROMP) and ring-closing olefin metathesis (RCM) reactions using well-defined metal catalysts. The molybdenum alkylidene complex 1 and ruthenium carbenes 2 and 3 bearing PCy(3) or N-heterocyclic carbene ligands, respectively, can be used and are found to exhibit efficiency similar to that in chlorinated organic solvents. While compound 1 is readily soluble in scCO(2), complexes 2 and 3 behave like heterogeneous catalysts in this reaction medium. Importantly, however, the unique properties of scCO(2) provide significant advantages beyond simple solvent replacement. This pertains to highly convenient workup procedures both for polymeric and low molecular weight products, to catalyst immobilization, to reaction tuning by density control (RCM versus acyclic diene metathesis polymerization), and to applications of scCO(2) as a protective medium for basic amine functions. The latter phenomenon is explained by the reversible formation of the corresponding carbamic acid as evidenced by (1)H NMR data obtained in compressed CO(2). Together with its environmentally and toxicologically benign character, these unique physicochemical features sum up to a very attractive solvent profile of carbon dioxide for sustainable synthesis and production.

Evaluating and reporting astigmatism for individual and aggregate data

PURPOSE

To demonstrate the proper method for evaluating and reporting astigmatism for individual and aggregate data.

SETTING

University of Texas Medical School and Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.

METHODS

The surgically induced refractive change (SIRC) was determined for three data sets of patients who have had keratorefractive (photorefractive keratectomy) or cataract surgery. To make changes in refraction comparable, vertex distances for the refractions and keratometric index of refraction were considered. Doubledangle plots and single-angle plots were then used to display the data. Polar values (cylinder and axis) were converted to a Cartesian (x and y) coordinate system to determine the mean value of the induced astigmatism for each data set.

RESULTS

Doubled-angle plots clearly demonstrated the trends of induced astigmatism for each data set, and the mean value for induced astigmatism agreed exactly with the intuitive appearance of the plot.

CONCLUSIONS

Converting astigmatism data to a Cartesian coordinate system allowed the correct computation of descriptive statistics such as mean values, standard deviations, and correlation coefficients. Using doubled-angle plots to display the data provides the investigator with the best method of recognizing trends in the data.

Diffuse lamellar keratitis associated with epithelial defects after laser in situ keratomileusis

PURPOSE

To describe the association between the presence of epithelial defects and the development of diffuse lamellar keratitis (DLK), "Sands of the Sahara" syndrome, following laser in situ keratomileusis (LASIK).

SETTING

Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.

METHODS

In this retrospective study, the postoperative clinical course and surgical outcomes in 735 eyes of 358 consecutive patients who had myopic LASIK between December 1998 and August 1999 were reviewed. Of the 735 procedures, 680 were primary LASIK procedures and 55 were retreatments performed by lifting the existing flaps. The incidence and severity of DLK and the relationship of DLK to epithelial defects were tabulated.

RESULTS

Diffuse lamellar keratitis developed in 9 of the 16 eyes that had postoperative epithelial defects. Seventeen eyes without epithelial defects also developed DLK. The presence of an epithelial defect increased an individual's risk of developing DLK 24 times (95% confidence interval, 13 to 45). In 8 eyes, the inflammation resolved following treatment with intense topical corticosteroids. One eye had irrigation under the flap because of dense central inflammation; the final outcome was mild inferior corneal steepening. All eyes recovered preoperative best spectacle-corrected visual acuities.

CONCLUSION

Patients who have epithelial defects of any size following LASIK are at significantly increased risk of developing DLK.

Guiding neuronal growth with light

Control over neuronal growth is a fundamental objective in neuroscience, cell biology, developmental biology, biophysics, and biomedicine and is particularly important for the formation of neural circuits in vitro, as well as nerve regeneration in vivo [Zeck, G. & Fromherz, P. (2001) Proc. Natl. Acad. Sci. USA 98, 10457-10462]. We have shown experimentally that we can use weak optical forces to guide the direction taken by the leading edge, or growth cone, of a nerve cell. In actively extending growth cones, a laser spot is placed in front of a specific area of the nerve's leading edge, enhancing growth into the beam focus and resulting in guided neuronal turns as well as enhanced growth. The power of our laser is chosen so that the resulting gradient forces are sufficiently powerful to bias the actin polymerization-driven lamellipodia extension, but too weak to hold and move the growth cone. We are therefore using light to control a natural biological process, in sharp contrast to the established technique of optical tweezers [Ashkin, A. (1970) Phys. Rev. Lett. 24, 156-159; Ashkin, A. & Dziedzic, J. M. (1987) Science 235, 1517-1520], which uses large optical forces to manipulate entire structures. Our results therefore open an avenue to controlling neuronal growth in vitro and in vivo with a simple, noncontact technique.

Refractive complications of cataract surgery after radial keratotomy

Four patients underwent cataract extraction with posterior chamber lens implantation several years after radial keratotomy. All four patients experienced an initial hyperopic shift caused by an early postoperative corneal flattening of greater than or equal to 1 diopter. This flattening partially regressed, leaving the patients with a mean of 0.42 diopter of persistent corneal flattening. We found the Binkhorst and the Holladay intraocular lens calculation formulas to be more accurate than the SRK II for these patients. Corneal curvature measured with the keratometer was less accurate for intraocular lens calculations than was a value derived by subtracting the refractive change induced by the radial keratotomy from the patients' keratometric measurements obtained before radial keratotomy.

Posterior polar cataracts: a predisposition to intraoperative posterior capsular rupture

We performed phacoemulsification or planned extracapsular cataract extraction on posterior polar cataracts in 31 eyes of 22 patients and experienced eight cases of posterior capsular rupture (26%). Capsular rupture occurred during removal of the posterior polar opacity or during cleaning of the posterior capsule after the opacity had been removed. We believe that excessive adherence of the opacity to the posterior capsule and unusual thinness of the capsule predisposed these eyes to posterior capsular rupture.

Cell motility and local viscoelasticity of fibroblasts

Viscoelastic changes of the lamellipodial actin cytoskeleton are a fundamental element of cell motility. Thus, the correlation between the local viscoelastic properties of the lamellipodium (including the transitional region to the cell body) and the speed of lamellipodial extension is studied for normal and malignantly transformed fibroblasts. Using our atomic force microscopy-based microrheology technique, we found different mechanical properties between the lamellipodia of malignantly transformed fibroblasts (H-ras transformed and SV-T2 fibroblasts) and normal fibroblasts (BALB 3T3 fibroblasts). The average elastic constants, K, in the leading edge of SV-T2 fibroblasts (0.48 +/- 0.51 kPa) and of H-ras transformed fibroblasts (0.42 +/- 0.35 kPa) are significantly lower than that of BALB 3T3 fibroblasts (1.01 +/- 0.40 kPa). The analysis of time-lapse phase contrast images shows that the decrease in the elastic constant, K, for malignantly transformed fibroblasts is correlated with the enhanced motility of the lamellipodium. The measured mean speeds are 6.1 +/- 4.5 microm/h for BALB 3T3 fibroblasts, 13.1 +/- 5.2 microm/h for SV-T2 fibroblasts, and 26.2 +/- 11.5 microm/h for H-ras fibroblasts. Furthermore, the elastic constant, K, increases toward the cell body in many instances which coincide with an increase in actin filament density toward the cell body. The correlation between the enhanced motility and the decrease in viscoelastic moduli supports the Elastic Brownian Ratchet model for driving lamellipodia extension.

Limbal relaxing incisions with cataract surgery

PURPOSE

To evaluate the effectiveness of limbal relaxing incisions (LRIs) for correcting corneal astigmatism during cataract surgery.

SETTING

Cullen Eye Institute, Houston, Texas, USA.

METHODS

In 12 eyes of 11 patients, cataract surgery was combined with LRIs. The LRIs were made according to a modified Gills nomogram and were based on preoperative corneal astigmatism determined with standard keratometry and computerized videokeratography (EyeSys Corneal Analysis System Version 3.2).

RESULTS

The mean preoperative keratometric cylinder was 2.46 +/- 0.81 diopters (D). At 1 month postoperatively, mean arithmetic reduction in keratometric cylinder was 1.12 +/- 0.74 D, and the with-the-wound (WTW) change (calculated by Holladay, Cravy, Koch vector analysis formula) was -0.70 +/- 0.44. From 1 day to 1 month postoperatively, there was 0.55 D of WTW regression with minimal change in the mean cylindrical axis. There were no overcorrections.

CONCLUSION

Limbal relaxing incisions are a practical, simple, and forgiving approach to the correction of astigmatism during cataract surgery.

Visual results and complications of phacoemulsification with intraocular lens implantation performed by ophthalmology residents

The authors retrospectively analyzed the visual outcome and incidence of complications of 181 consecutive cases of phacoemulsification performed by eight third-year ophthalmology residents. A posterior chamber intraocular lens was implanted in 179 of these eyes. Vitreous loss occurred in 5.5% of cases. The overall incidence of posterior capsule rupture was 9.9%; of the 18 posterior capsular ruptures, 72% were detected during cortical removal and 22% during nuclear emulsification. Postoperative follow-up for 177 eyes was at least 2 months, and 70% were followed for 6 months or longer. Final best corrected visual acuity of 20/40 or better was obtained in 92.6% of eyes. These results are comparable with previous reports of residents' experience in performing planned extracapsular cataract extraction. With appropriate training and faculty supervision, residents learning to perform phacoemulsification and intraocular lens implantation can achieve acceptable results.

Optic neuropathy associated with laser in situ keratomileusis

PURPOSE

To report 4 cases of optic neuropathy following laser in situ keratomileusis (LASIK).

SETTING

Tertiary Care ophthalmic practices.

METHODS

In this retrospective observational case series, 4 patients who developed acute visual loss following LASIK are reported. All had clinical evidence of optic neuropathy. Two had optic disc edema and 2 had normal appearing optic discs initially. None of the patients experienced significant visual recovery, and all developed optic atrophy in the affected eye.

RESULTS

All patients had evaluations for alternative etiologies of their optic neuropathy, with negative results. All patients were therefore presumed to have experienced an ischemic optic neuropathy following LASIK.

CONCLUSIONS

Patients who have LASIK may experience an acute anterior or retrobulbar optic neuropathy. The etiology is unknown but may be related to the marked increase in intraocular pressure that occurs during a portion of the procedure.

Axial myopia increases the risk of retinal complications after neodymium-YAG laser posterior capsulotomy

We conducted a retrospective analysis of Q-switched neodymium-YAG laser capsulotomies performed in 122 eyes between April 1984 and June 1987. Retinal complications occurred in 3 (2.5%) of 121 eyes followed up for 1 year and in 2 (3.6%) of 55 eyes followed up for 2 years. Four eyes developed rhegmatogenous retinal detachments and 1 developed an acute symptomatic retinal tear. No patients developed clinical cystoid macular edema (visual acuity 20/30 or worse). These retinal complications were significantly correlated with axial myopia, preexisting vitreoretinal disease, male gender, younger age, vitreous prolapse into the anterior chamber, and spontaneous extension of the capsulotomy.

A chimeric receptor that selectively targets membrane-bound carcinoembryonic antigen (mCEA) in the presence of soluble CEA

Chimeric T cell receptors with specificity for tumor-associated antigens are successfully used to target T cells to tumor cells. The efficacy of this approach, however, is reduced by soluble antigen that is frequently present in high serum concentrations. To overcome this situation, we constructed an anti-CEA chimeric receptor whose extracellular moiety is composed of a humanized single chain antibody fragment (scFv) derived from the anti-CEA mAb BW431/26 and the CH2/CH3 constant domains of human IgG. The intracellular moiety consists of the gamma-signaling chain of the human Fc epsilon RI receptor constituting a completely humanized chimeric receptor. After transfection, the humBW431/26 scFv-CH2CH3-gamma receptor is expressed as a homodimer on the surface of MD45 T cells. Co-incubation with CEA+ tumor cells specifically activates grafted MD45 T cells indicated by IL-2 secretion and cytolytic activity against CEA+ tumor cells. Notably, the efficacy of receptor-mediated activation is not affected by soluble CEA up to 25 micrograms/ml demonstrating the usefulness of this chimeric receptor for specific cellular activation by membrane-bound CEA even in the presence of high concentrations of CEA, as found in patients during progression of the disease.

A comparison of corneal endothelial changes after use of Healon or Viscoat during phacoemulsification

We conducted a prospective, randomized trial comparing the endothelial protective effects of Healon (Kabi Pharmacia Ophthalmics, Inc., Monrovia, California) and Viscoat (Alcon Surgical, Inc., Ft. Worth, Texas) in 59 eyes of 59 patients undergoing iris-plane or posterior-chamber phacoemulsification with posterior-chamber lens implantation. We evaluated postoperative central and superior changes in corneal thickness and corneal endothelial cell density, coefficient of variation in cell size, and percentage of hexagons. In the overall series, at one day postoperatively, corneal thickness increased 17% centrally and superiorly in eyes receiving Healon compared to 12% centrally and 11% superiorly in eyes receiving Viscoat (P < .05). Sixteen weeks postoperatively, superior endothelial cell loss was 11.6% in eyes receiving Healon compared to 2.1% in eyes receiving Viscoat (P < .01). In the iris-plane phacoemulsification group, superior cell loss at week 16 was 13.8% in eyes receiving Healon and 0.5% in eyes receiving Viscoat (P < .04). In the posterior-chamber phacoemulsification group, there were no significant differences between the Healon and Viscoat subgroups. Comparing the surgical techniques, in the Healon group, central cell loss at week 16 was 13.8% in the iris-plane phacoemulsification subgroup and 0.6% in the posterior-chamber phacoemulsification subgroup (P < .03), and coefficient of variation in cell size increased 3.7% in the iris-plane subgroup and decreased 6.8% in the posterior-chamber subgroup (P < .04). In the Viscoat group, there were no significant differences between surgical techniques at week 16. Viscoat provided greater corneal endothelial protection than Healon during iris-plane phacoemulsification. In eyes receiving Healon, posterior-chamber phacoemulsification resulted in less corneal endothelial trauma than the iris-plane technique.

Safety and feasibility of long-term temozolomide treatment in patients with high-grade glioma

We surveyed neuro-oncologists regarding patients treated with temozolomide for at least 12 cycles or 12 months. Patients receiving first-line temozolomide for a median 13 cycles had a median progression-free survival (PFS) of 14 months. Patients with recurrent disease receiving a median 14 cycles had a median PFS of 15.5 months. A small percentage of patients experienced grade III to IV toxicity. These results suggest that long-term treatment with temozolomide is feasible and well tolerated.

Hyperopia correction by noncontact holmium:YAG laser thermal keratoplasty. Clinical study with two-year follow-up

BACKGROUND

Thermal keratoplasty to correct hyperopia has been attempted with nonlaser and laser devices. Problems have included long-term regression and irregular induced astigmatism. The present clinical study was performed to investigate the safety, efficacy, and stability of a noncontact mode of holmium: YAG laser energy delivery and a modified laser thermal keratoplasty treatment procedure for correction of low hyperopia.

METHODS

Seventeen patients underwent noncontact holmium: YAG laser thermal keratoplasty in their nondominant eyes for correction of hyperopia of up to 3.00 diopters. Treatment parameters included simultaneous delivery of eight holmium: YAG laser spots in a symmetrical octagonal array with a centerline diameter of 6mm, 10 pulses of laser light at 5-Hz pulse repetition frequency, and pulse energies of 159 to 199mJ. Follow-up was 2 years in 15 of 17 patients.

RESULTS

In the 15 eyes examined at 2 years after surgery, mean uncorrected distance Snellen visual acuity improved from 20/125-1 to 20/50-2. The mean change in spherical equivalent of subjective manifest refraction was -0.79 diopter. Eleven of these 15 eyes (73%) had a mean refractive correction of -1.1 diopters (range, -0.38 to -2.63 diopters); regression between 14 days and 2 years was 0.2 diopter. Four eyes (27%) had no persistent refractive correction (within +/- 0.25 diopter). Mean induced refractive astigmatism was 0.18 diopter. None of the eyes lost two or more lines of spectacle-corrected distance vision. The amount of refractive correction at 2 years after surgery was correlated to the treatment pulse energy and the volume of the opacified corneal tissue observed immediately after treatment.

CONCLUSIONS

This technique of noncontact laser thermal keratoplasty produced safe, effective, and persistent corrections of low hyperopia in the majority of treated eyes.

Atypical teratoid/rhabdoid tumors in adult patients: case report and review of the literature

Atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system are rare and extremely aggressive malignancies of early childhood. We report a case of AT/RT in an adult patient. A 30-year-old woman presented with headache, vomiting and ataxia during the second trimester of pregnancy. Magnetic resonance imaging revealed a posterior fossa mass. A gross total resection was performed. Pathological examination revealed an AT/RT. Despite the dismal prognosis the patient decided not to undergo an abortion. For this reason postoperative accelerated hyperfractionated radiotherapy was limited to the tumor region. Six months later the woman delivered a healthy baby. One week postpartum, a central nervous system recurrence localized apart from the primary lesion was treated with radiosurgery. Two months later a diffuse progression was noted. Despite a 6 week course of oral temozolomide, the tumor progressed and the patient died 11 months after diagnosis. Although survival was short, surgery and involved field radiotherapy yielded a progression-free interval of 9 months. This allowed the patient to carry pregnancy to term. Radiosurgery resulted in a complete remission of the first recurrence. Oral chemotherapy was not effective in controlling diffuse tumor spread.

Evaluation of intraocular pressure with Healon and Healon GV in sutureless cataract surgery with foldable lens implantation

PURPOSE

To evaluate transient increases in intraocular pressure (IOP) after use of high-viscosity viscoelastic agents in cataract surgery.

SETTING

Military Hospital, Ulm, Germany.

METHODS

In a prospective, randomized study, we evaluated IOP following cataract surgery using two different viscoelastic substances (Healon, Healon GV). The viscosity of Healon GV is 10 times higher than that of Healon because of higher concentration and molecular weight. Patients having identical phacoemulsification procedures (sutureless clear corneal tunnel incision with foldable silicone lens implantation) (N = 60) and identical viscoelastic removal were assigned to groups of 15 based on viscoelastic used and removal time (20 or 40 seconds). Intraocular pressure was measured preoperatively and at 6, 24, 36, and 48 hours and 1 month postoperatively.

RESULTS

The highest mean IOP elevations in both viscoelastic groups were obtained at 24 hours postoperatively (2.9 mm Hg +/- 4.3 [SD] with Healon and 3.3 +/- 6.3 mm Hg with Healon GV). There were no statistically significant differences between the two viscoelastics and the two removal times during the entire follow-up period (unpaired t-test), but standard deviations were higher in the Healon GV groups at 6 and 24 hours. Two patients in the Healon groups and three in the Healon GV groups required medical treatment for IOP within the first 24 postoperative hours; however, all five patients had an IOP lower than 22 mm Hg on the second postoperative day.

CONCLUSIONS

Based on postoperative IOP, both viscoelastics can be equally well removed from the anterior chamber. Incidence of high IOP using high-viscosity hyaluronic acid is minimized by the described removal technique.

Comparison of changes in manifest refraction and corneal power after photorefractive keratectomy

PURPOSE

To determine which corneal curvature values most closely correlate to change in manifest refraction after excimer laser photorefractive keratectomy.

METHODS

In a prospective study at the Cullen Eye Institute, excimer laser photorefractive keratectomy was performed on 27 eyes of 27 patients (mean age, 38.07+/-6.65 years). Preoperative refractive errors ranged from -2.25 diopters to -8.75 diopters (mean, -5.74+/-2.09 diopters). Preoperatively and 1 month postoperatively, we determined the spherical equivalent of the subjective manifest refraction (corrected for a 12-mm vertex distance) and measured corneal power using standard keratometry (Bausch & Lomb Keratometer; Rochester, New York) and computerized videokeratography (EyeSys Corneal Analysis System; Premier Laser Systems Inc, Houston, Texas). We collected 15 corneal values: standard keratometry and 14 computerized videokeratography values calculated using the axial, instantaneous, and refractive formulas. All calculations were performed with 1.3375 and 1.376 for the refractive index of the cornea. For each of the corneal values, we subtracted the change in corneal power from the change in manifest refraction and calculated for this difference the means, SDs, correlations, and regressions.

RESULTS

Mean differences between change in refraction and change in corneal power were lower when for a refractive index of 1.376 than for 1.3375, were lowest for the most central measurement points, and displayed a high SD. A value of 1.408 for the refractive index would be required to optimize the correlation between change in manifest refraction and effective refractive power of the central 3 mm of the cornea.

CONCLUSIONS

For individual patients who have undergone photorefractive keratectomy, changes in corneal values determined by computerized videokeratography or by standard keratometry do not reliably predict change in manifest refraction.

Acute and chronic conjunctivitis due to over-the-counter ophthalmic decongestants

OBJECTIVE

To describe patterns of conjunctivitis caused by ophthalmic decongestants.

DESIGN

Case series.

SETTING

Outpatient eye clinic.

PATIENTS

We selected patients with conjunctival inflammation who were using nonprescription decongestant eyedrops, who had no other cause for conjunctivitis, and whose conditions improved after discontinuing the incriminated preparations.

MAIN OUTCOME MEASURES

Clinical characteristics of conjunctival inflammation and time to resolution of symptoms and signs after discontinuing the use of eyedrops.

RESULTS

Seventy patients (137 eyes) were identified. Preparations containing the vasoconstrictors naphazoline, tetrahydrozoline, or phenylephrine were associated with 3 clinical patterns of conjunctivitis: conjunctival hyperemia (50 cases), follicular conjunctivitis (17 cases), and eczematoid blepharoconjunctivitis (3 cases). Decongestants were used daily for a median of 3 years (range, 8 hours to 20 years) prior to presentation. The median time to resolution of symptoms and signs was 4 weeks (range, 1-24 weeks), and patients remained asymptomatic for a median follow-up of 6 months (range, 0-12 years).

CONCLUSION

Nonprescription decongestant eyedrops can produce acute and chronic forms of conjunctivitis by pharmacological, toxic, and allergic mechanisms. Once recognized, conjunctival inflammation often takes several weeks to resolve.

Epidemiology and antifungal resistance in invasive candidiasis

The epidemiology of Candida infections has changed over the last two decades: The number of patients suffering from such infections has increased dramatically and the Candida species involved have become more numerous as Candida albicans is replaced as an infecting agent by various non-C. albicans species (NAC). At the same time, additional antifungal agents have become available. The different Candida species may vary in their susceptibility for these various antifungals. This draws more attention to in vitro susceptibility testing. Unfortunately, several different test methods exist that may deliver different results. Moreover, clinical breakpoints (CBP) that classify test results into susceptible, intermediate and resistant are controver- sial between CLSI and EUCAST. Therefore, clinicians should be aware that interpretations may vary with the test system being followed by the microbiological laboratory. Thus, knowledge of actual MIC values and pharmacokinetic properties of individual antifungal agents is important in delivering appropriate therapy to patients

Comparison of the accuracy and reproducibility of the keratometer and the EyeSys Corneal Analysis System Model I

The EyeSys Corneal Analysis System Model I measures corneal topography using digital image analysis of placido rings reflected off the cornea. With three observers, we compared the accuracy and reproducibility (precision) of the Marco Keratometer Model 1 and EyeSys Corneal Analysis System Model I using four poly(methyl methacrylate) spheres (37.50, 42.51, 47.54, and 55.06 diopters [D]), three steel spheres (40.50, 42.50, and 44.75 D), and 20 normal human eyes (41.50 to 46.00 D). For the spheres, the standard deviations of intra-observer and overall reproducibility for both devices were less than 0.12 D; the absolute mean differences between the measurements of the seven spheres and the known values were 0.25 D or more for two spheres as measured by the keratometer and none as measured by the EyeSys. For the normal corneas, the standard deviations of intra-observer and overall reproducibility for dioptric measurements were 0.07 D and 0.14 D for the keratometer and 0.13 D and 0.19 D for the EyeSys. The EyeSys Corneal Analysis System Model I exceeds keratometer accuracy in reading calibrated spheres and approaches keratometer reproducibility in measuring the 3-mm zone of normal human corneas.