Keratomileusis Procedure Research Articles

Thin-flap laser-assisted in situ keratomileusis

Concerns regarding the increasing incidence of corneal ectasia following laser in situ keratomileusis procedures, together with increased understanding of the biomechanics of the cornea, has resulted in many refractive surgeons returning to surface ablation techniques such as photorefractive keratectomy. Even if surface ablation techniques offer a higher degree of safety than LASIK, they are associated with more pain and a slower visual recovery in the immediate postoperative period. This highlights the need for alternative procedures that offer the combined advantages of laser in situ keratomileusis and photorefractive keratectomy. Sub-Bowman's keratomileusis is a new procedure that provides the biomechanical stability and associated safety of photorefractive keratectomy with the visual results and reduced pain experience of laser in situ keratomileusis. This technique involves the use of the femtosecond laser to create a customized corneal flap of between 90 and 110 mum with a diameter based on the requirements of the individual patient and the type of excimer laser being used. This review outlines the rationale for sub-Bowman's keratomileusis and describes the efficacy, tolerability and safety of the procedure compared with photorefractive keratectomy.

Microbial cultures of the microkeratome blade immediately after flap construction in laser in situ keratomileusis

To assess the incidence of positive cultures from samples of the microkeratome blade after routine laser in situ keratomileusis (LASIK) procedures as a measure of the risk for postoperative infectious keratitis. Hinsdale Surgical Center, Hinsdale, Illinois, USA. In this prospective study, 99 microkeratome blades (Hansatome) were cultured after routine LASIK procedures by multiple surgeons at an ambulatory surgery center. Cultures were sent for routine aerobic and anaerobic growth. Positive cultures were then sent for routine sensitivities. Five of 99 swabs of microkeratome blades were culture positive. Four cultures grew Staphylococcus epidermidis and 1, Staphylococcus warneri. Two of the staphylococcal cultures were resistant to ciprofloxacin and levofloxacin but sensitive to moxifloxacin and gatifloxacin. The study demonstrated a 5% positive culture rate from the microkeratome blade after routine LASIK surgery by multiple surgeons in an ambulatory surgery center. No patient with positive cultures developed postoperative infectious keratitis. Factors other than the presence of bacteria contribute to the development of clinical infection.

Possible retina damage potential of the femtosecond laser in situ keratomileusis (fs-LASIK) refractive surgery

Abstract Since the early 1990s, the laser in situ keratomileusis (LASIK) procedure has been successfully implemented in refractive eye surgery to correct ametropia. Rapid development in new laser technology enables the application of ultrashort laser pulses in the femtosecond (fs) regime that marks advancement in conventional standard procedures of refractive surgery by eliminating the use of mechanical knives. With the fs-LASIK procedure, ultrashort laser pulses focus in the near-infrared spectral range and create a laser-induced breakdown (LIB) that disrupts the corneal tissue. During the cutting process not all of the pulse energy is deposited in the cornea. Approximately half the remaining energy is propagated through the eye and reaches the retina, as well as the strongly absorbing layers behind. In the current standard refractive surgery procedures, such as photorefractive keratomileusis (PRK) and LASIK, retina damage is reduced because of the complete absorption of ultraviolet irradiation by corneal tissue during ablation. The aim of this project was to investigate possible retina damage under fs-LASIK conditions and to optimize external parameters during surgery, such as pulse energy and numerical aperture, to reduce risk potential. The process was simulated with a conventional fs-laser system integrated into an experimental set-up. To investigate the retina damage thresholds, in vivo investigations were carried out systematically on enucleated porcine eyes. Damage thresholds were determined in terms of macroscopic and histopathological observations. The results of these studies indicate possible retina damage.

Analysis of ectasia after laser in situ keratomileusis: Risk factors

To examine a database of laser in situ keratomileusis (LASIK) procedures for preoperative and operative factors assumed to increase the risk for developing post-LASIK ectasia. Private clinical practice. A computer database was queried for eyes that had LASIK for myopic refractive errors with the following characteristics: preoperative corneal thickness 500 microm or less, mean keratometry greater than 47.0 diopters (D), patient age 25 years or younger, attempted correction greater than -8.0 D, refractive astigmatism not with-the-rule and greater than 2.0 D, and residual stromal bed thickness (RST) 250 microm or less. Flap thickness and RST were measured using ultrasound pachymetry. All recorded information was exported to MS Excel and analyzed for eyes that had ectasia. Of the 9700 eyes in the database, none with the above characteristics developed ectasia over mean follow-up periods exceeding 2 years. Seven eyes had multiple risk factors without ectasia. Three eyes with abnormal preoperative topography developed ectasia. Individual preoperative and operative factors did not in and of themselves increase the risk for ectasia. Unmeasured and unknown factors that affect the individual cornea's biomechanical stability, in combination with some suspected risk factors as well as the current inability to identify corneas at risk for developing ectatic disorders, probably account for most eyes that develop ectasia today.

Oestrogen-induced changes in biomechanics in the cornea as a possible reason for keratectasia

Aim:The risk of regression after photorefractive keratectomy (PRK) and the tendency to develop keratectasia after laser-assisted in situ keratomileusis (LASIK) procedure is higher in women than men. Currently, interest is...

Comparative Study of Stromal Bed Quality by Using Mechanical, IntraLase Femtosecond Laser 15- and 30-kHz Microkeratomes

To evaluate corneal stromal bed quality of lamellar keratectomy in laser in situ keratomileusis (LASIK) procedures by using mechanical and femtosecond laser microkeratomes. LASIK corneal flaps were created in 9 fresh human globes not suitable for transplantation. We grouped the samples into 3 different groups of 3 globes each. Group 1 was the control group, in which the flaps were created using a Hansatome microkeratome with a 160-microm head. Groups 2 and 3 consisted of flaps created at the 110-microm flap thickness setting using the IntraLase 15- and 30-kHz femtosecond laser, respectively. All the flaps were removed, and the corneal stromal beds were prepared for scanning electron microscopy (SEM). Qualitative surface roughness (QlSR) of the SEM images was graded using a roughness grading scale from 1 to 5 by 3 masked observers. Quantitative surface roughness (QnSR) of the SEM images was also assessed using software designed for roughness analysis. Mann-Whitney nonparametric statistical analysis was performed to compare groups. There was no statistically significant difference in QlSR and QnSR scores between group 2 and group 1 (brand-new blade only). Group 3 30-kHz IntraLase samples showed a smoother stromal bed compared with group 1 and 2 samples. This was a statistically significant difference for QlSR (QlSR = 1.1 +/- 0.17, P < 0.001) and showed borderline significance for QnSR (QnSR = 24.4 +/- 0.96, P = 0.05). The IntraLase 15-kHz femtosecond laser 110-microm flaps and the Hansatome 160-microm head using a new blade both produced smooth, good-quality, compact stromal beds as assessed qualitatively by masked observers and quantitatively by image analysis software. The 30-kHz femotsecond laser permits a tighter spot/line separation and lower energy per pulse, which creates smoother corneal stromal beds.

Laser in situ keratomileusis for astigmatism following laser thermal keratoplasty

We describe 2 cases in which a staged laser in situ keratomileusis procedure was used to treat residual hyperopia and astigmatism after laser thermal keratoplasty. The procedure successfully reduced the spherical equivalent refractive error and residual astigmatism. All eyes maintained their best spectacle-corrected visual acuity and had an uncorrected visual acuity of at least 20/25 at the end of follow-up.

Two-step laser in situ keratomileusis to correct high astigmatism after corneal autograft

We report a case in which significant anisometropia and astigmatism after an autograft by rotation was treated by a 2-step laser in situ keratomileusis (LASIK) procedure. Six weeks after the lamellar keratotomy, photoablation was performed using the LADARVision 4000 excimer laser. The ablation depth was 87.2 mum on a 6.0 mm optical zone. One day postoperatively, the uncorrected visual acuity (UCVA) was 7/10 and the refractive error was -0.25 -0.25 x 67. Two months later, the UCVA was 5/10 and the best corrected visual acuity, 8/10 Parinaud 2 with a refractive error of +1.75 -1.25 x 16. The case demonstrates the effectiveness of 2-step LASIK for the correction of astigmatism induced by a corneal autograft. The significant reduction in autograft-induced astigmatism, together with stabilization of the higher-order aberrations, resulted in restoration of satisfactory functional vision.

Corneal Ectasia After Laser In Situ Keratomileusis in Patients Without Apparent Preoperative Risk Factors

To evaluate patients who developed ectasia with no apparent preoperative risk factors. Potential cases of patients who developed ectasia without apparent risk factors were identified by contacting participants in the Kera-Net (n = 580), ASCRS-Net (n = 450), and ISRS/AAO ISRS-Net (n = 525) internet bulletin boards from April to October 2003. Cases were included if ectasia developed after laser in situ keratomileusis in the absence of apparent preoperative risk factors. Reported cases were excluded for the following reasons: (1) calculated residual stromal bed less than 250 microm, (2) preoperative central pachymetry less than 500 microm, (3) any keratometry reading greater than 47.2 diopters (D), (4) a calculated inferior-superior value greater than 1.4, (5) more than 2 retreatments, (6) attempted initial correction greater than -12.00 D, (7) an Orbscan II "posterior float" (if obtained) greater than 50 microm, and (8) surgical/flap complications. A total of 27 eyes of 25 patients were submitted for consideration. Eight eyes (8 patients) met our inclusion criteria. Mean age was 27.7 years (range, 18-41 years). Preoperative manifest refraction spherical equivalent was -4.61 D (range, -2.00 to -8.00 D); steepest keratometric reading was 43.86 D (range, 42.50-46.40 D); keratometric astigmatism was 0.93 D (range, 0.25-1.90 D); and preoperative central pachymetry was 537 microm (range, 505-560 microm). The mean calculated ablation depth was 82.8 microm (range, 21-125.4 microm), and mean calculated residual stromal bed was 299.5 microm (range, 254-373 microm). Mean time to recognition of ectasia onset was 14.2 months (range, 3-27 months) postoperatively. At the time of ectasia diagnosis, the mean manifest refraction spherical equivalent was -1.23 D (range, +0.125 to -3.00) with a mean of 2.72 D (range, 0.75-4.00 D) of astigmatism. Ectasia can occur after an otherwise uncomplicated laser in situ keratomileusis procedure, even in the absence of apparent preoperative risk factors.

Improved contrast sensitivity and visual acuity after wavefront-guided laser in situ keratomileusis: In-depth statistical analysis

To evaluate changes in contrast sensitivity and visual acuity following wavefront-guided laser in situ keratomileusis (LASIK) procedures with the Visx CustomVue system. Six clinical sites that participated in an Investigational Device Exemption clinical study. Two hundred seventy-four myopic astigmatic eyes (spherical equivalent range -0.63 to -6.00 diopters) completed 6 months of follow-up examinations. Wavefront-guided procedures using the WaveScan aberrometer and Star S4 excimer laser system with variable spot scanning were performed at 6 clinical locations. Visual acuity and contrast sensitivity under photopic, mesopic, and mesopic-with-glare lighting conditions were tested preoperatively and over a 6-month follow-up period. This study was a retrospective analysis of contrast sensitivity data with controls for the effects of retinal magnification, mesopic pupil size, and the influence of prior soft contact lens wear on visual outcome. Patients experienced statistically significant improvements in contrast sensitivity at all spatial frequencies and under all lighting conditions (P<.05, Student t test). Contrast sensitivity under mesopic conditions with glare improved in 40% of patients. There was more improvement at higher (12 cycles per degree [cpd], 18 cpd) than lower (3 cpd) spatial frequencies. No correlation was found between mesopic pupil size and contrast sensitivity. Results stratified by spectacle or soft contact lens wear were similar. Soft contact lens wearers had slightly higher disability glare scores than spectacle wearers. A significant number of patients experienced improved corneal optical quality after wavefront-guided LASIK. The contrast sensitivity in most patients was unchanged. Contrast sensitivity improved in a significant number of patients. There was no correlation between mesopic pupil size and mesopic or mesopic-with-glare contrast performance. Spectacle wearers improved more than soft contact lens wearers.

Contact lens overrefraction variability in corneal power estimation after refractive surgery

To evaluate the accuracy and precision of the contact lens overrefraction (CLO) method in determining corneal refractive power in post-refractive-surgery eyes. Refractive Surgery Service and Contact Lens Service, University of Illinois, Chicago, Illinois, USA. Fourteen eyes of 7 subjects who had a single myopic laser in situ keratomileusis procedure within 12 months with refractive stability were included in this prospective case series. The CLO method was compared with the historical method of predicting the corneal power using 4 different lens fitting strategies and 3 refractive pupil scan sizes (3 mm, 5 mm, and total pupil). Rigid lenses included 3 9.0 mm overall diameter lenses fit flat, steep, and an average of the 2, and a 15.0 mm diameter lens steep fit. Cycloplegic CLO was performed using the autorefractor function of the Nidek OPD-Scan ARK-10000. Results with each strategy were compared with the corneal power estimated with the historical method. The bias (mean of the difference), 95% limits of agreement, and difference versus mean plots for each strategy are presented. In each subject, the CLO-estimated corneal power varied based on lens fit. On average, the bias between CLO and historical methods ranged from -0.38 to +2.42 diopters (D) and was significantly different from 0 in all but 3 strategies. Substantial variability in precision existed between fitting strategies, with the range of the 95% limits of agreement approximating 0.50 D in 2 strategies and 2.59 D in the worst-case scenario. The least precise fitting strategy was use of flat-fitting 9.0 mm diameter lenses. The accuracy and precision of the CLO method of estimating corneal power in post-refractive-surgery eyes was highly variable on the basis of how rigid lense were fit. One of the most commonly used fitting strategies in clinical practice--flat-fitting a 9.0 diameter lens-resulted in the poorest accuracy and precision. Results also suggest use of large-diameter lenses may improve outcomes.

Surgeon offsets and dynamic eye movements in laser refractive surgery

To determine the amount of static and dynamic pupil decentrations that occur during laser refractive surgery. The Center of Visual Science and the Department of Ophthalmology, University of Rochester, Rochester, New York, USA. The surgeon's accuracy in aligning the pupil center with the laser center axis was measured when engaging the eye-tracker in 17 eyes receiving conventional laser in situ keratomileusis (LASIK) procedures (Technolas 217z; Bausch & Lomb). Eye movements were measured subsequently during the treatment in 10 eyes using a pupil camera operating at 50 Hz. Temporal power spectra were calculated from the eye movement measurements. The mean pupil misalignment by the surgeon at the beginning of the procedure was 206.1 microm +/- 80.99 (SD) (with respect to the laser center). The laser center was typically misaligned below (inferiorly) and to the left (nasally and temporally in left and right eyes, respectively) of the pupil [corrected] center. Small amounts of cyclotorsion were observed during the ablation (<2 degrees). The mean magnitude of dynamic pupil decentration from the laser center during treatment was 227.0 +/- 44.07 microm. The mean standard deviation of eye movements was 65.7 +/- 25.64 microm. Temporal power spectra calculated from the horizontal and vertical changes in eye position during the ablation were similar. Ninety-five percent of the total power of the eye movements was contained in temporal frequencies up to 1 Hz, on average, in both directions. Most eye movements during LASIK are slow drifts in fixation. An eye-tracker with a 1.4 Hz closed-loop bandwidth could compensate for most eye movements in conventional or customized ablations.

Amadeus microkeratome: experience with the first 2000 cases and lessons learned

To assess the safety and efficacy of the Amadeus microkeratome and to report on lessons learnt in optimizing results from its use. A retrospective review of the flap-related complications of 2000 laser in situ keratomileusis (LASIK) procedures performed by one surgeon using the Amadeus microkeratome (AMO, Irvine, CA, USA) was conducted. One hundred consecutive cases had preoperative and intraoperative pachymetry to evaluate the relationship between flap thickness, corneal thickness and reuse of the blade. There were 35 cases of minor epithelial defects (1.8%) and four eyes with major epithelial defects (0.2%). There were no cases of suction loss, buttonholes, or incomplete or damaged flaps. There were four free caps (0.2%). Twenty-five cases had minor wrinkles and two cases had significant folds requiring relifts. Thinner corneas resulted in thinner flaps (P < 0.0001). Reuse of the blade resulted in thinner flaps (P = 0.0001). The Amadeus is a safe and reliable microkeratome. Although short, there is a learning curve with use of the instrument. Corneal thickness and reuse of the blade affect flap thickness.

Pachymetric evaluation prior to laser in situ keratomileusis

To determine whether deviations in the localization of the cornea's thinnest point or the magnitude and localization of posterior corneal ectasia is associated with deviations in the spherical equivalent, the astigmatism, or the magnitude of an anterior corneal ectasia and whether corneas at risk for iatrogenic keratectasia can be identified without a pachymetry map of the cornea. University hospital eye clinic. Three hundred eight eyes of 156 healthy volunteers with various refractive errors were examined with Orbscan II and autorefractometer-keratometer. The corneal thickness was registered at the fixation point, at the geometrical center, and at the thinnest point of the cornea. Keratometry and refraction were determined for all subjects. The thinnest point of the cornea was predominantly located in the inferotemporal quadrant, and was significantly thinner than the fixation point (539.6 +/- 35.8 microm and 548.0 +/- 35.4 microm, respectively, P<.001). Interestingly, the larger this difference was, the longer the distance between these points. No relationship was found between the refractive or external surface measurements and the internal surface measurements. The absence of a clear relationship between the shape of the anterior corneal surface or the refractive error, and the shape of the posterior corneal surface, necessitates a thorough pachymetric evaluation of the cornea before a laser in situ keratomileusis procedure, with special attention to the inferotemporal area.

Flap and stromal bed thickness in laser in situ keratomileusis enhancement

Purpose: To evaluate whether flap thickness changes after the primary laser in situ keratomileusis (LASIK) procedure and to assess the accuracy of intraoperative pachymetry and ablation depth measurements in predicting stromal bed thickness before enhancement in eyes that have had primary myopic LASIK. Setting: Bascom Palmer Eye Institute, Miami, Florida, USA. Methods: This retrospective noncomparative interventional case series comprised 57 eyes of 42 patients who had LASIK enhancement between June 2001 and September 2002. Exclusion criteria included previous ocular surgery or complications during the first LASIK procedure. Only patients who had had LASIK and enhancement by the same surgeon at our institution and had intraoperative pachymetry readings for both procedures were included. The original flap was relifted in all enhancement procedures. Corneal thickness was routinely measured intraoperatively by ultrasound pachymetry. The age, eye, refraction, date of primary LASIK, central corneal thickness (CCT) and central stromal bed thickness at primary LASIK, depth of ablation, flap thickness (subtraction pachymetry), date of enhancement, CCT and central stromal bed thickness at enhancement, and flap thickness at enhancement were recorded. Results: Thirty-one eyes of 26 patients were myopic and 26 eyes of 16 patients were hyperopic before primary LASIK. The mean time between LASIK and enhancement was 218 days ± 115 (SD) (193 ± 88 days in myopic eyes and 248 ± 136 days in hyperopic eyes [ P = .068]). The flap tended to be thicker at enhancement than in the primary LASIK procedure by 9.3 ± 25.7 μm in myopic eyes ( P = .054) and 10.5 ± 16.6 μm in hyperopic eyes ( P = .004). A strong correlation was found between flap thickness in the first and second procedures in myopic and hyperopic eyes ( r = 0.6). In myopic eyes, the mean difference between the estimated stromal bed thickness after the first procedure (central bed thickness– ablation depth) and the stromal bed thickness measured directly at enhancement was not statistically significant (3 ± 29 μm; P = .54, paired t test). A strong correlation was found between the 2 measurements ( r = 0.8, P<.001). Another strong correlation was found in myopic eyes between the estimated corneal thickness after the primary LASIK and the corneal thickness measured at enhancement ( r = 0.81, P<.001). No correlation was found between the difference in flap thickness and the time to enhancement ( r = 0.09 in myopic eyes and r = 0.01 in hyperopic eyes). Conclusions: Flap thickness tended to be thicker at enhancement than at primary LASIK. Intraoperative pachymetry and ablation depth measurements proved to be precise tools to predict stromal bed thickness before enhancement in eyes that had had primary myopic LASIK. This information may help in planning LASIK enhancements.

Flap dimensions created with the IntraLase FS laser

Purpose: To assess the safety and predictability of the IntraLase femtosecond laser to create accurate flap thickness and diameter. Setting: Clinical office-based practice. Methods: In the first 103 eyes in which flaps were created with the IntraLase laser, the flap thickness was measured by the ultrasonic difference between the preoperative and post-flap-creation central corneal thickness and the flap diameter was measured with calipers. Results: As the attempted flap thickness decreased from 140.0 μm to 110.0 μm in 10.0 μm increments, the mean flap thickness decreased from 132.5 μm to 125.0 μm, with standard deviations decreasing from ±18.5 to ±12.0 μm. The mean flap diameter differed from the attempted diameter by less than 0.03 μm in all but the 130.0 μm group. Two slipped flaps and 20 cases of interface inflammation occurred early in the series. Conclusions: The IntraLase laser, while adding technical complexity to the laser in situ keratomileusis procedure, is able to predictably create flap diameters, hinge location, and flap thickness while eliminating the risk for cap perforations. The technique of flap elevation affects rapidity of visual recovery.

Surgeon factor on laser in situ keratomileusis in low and moderate myopia

The purpose of this study was to evaluate the effectiveness and predictability of laser in situ keratomileusis (LASIK) procedure performed by three surgeons in low and moderate myopia. One hundred twenty nine eyes from 68 patients underwent LASIK procedure, performed by three different surgeons (X, Y, Z) using the same procedure and same instruments were reviewed. These patients are divided into two groups, group A (below – 6.00 diopters) and group B (between – 6.00 and –10.00 diopters). Patients were observed on day 1, day 7, 1st month and 3rd month. Results: The evaluation of effectiveness and predictability is based upon uncorrected visual acuity (UCVA) and spherical equivalent refraction, respectively. The variation dispersion between attempted correction and achieved correction is measured using coefficient of determination (R2). The statistical analysis shows indifferent results for the three surgeons. The conclusion was that the effectiveness and predictability of LASIK procedure performed by the three surgeons in both groups are indifferent. Hence, this study suggests that the surgeon factor does not affect the result of LASIK procedure. (Med J Indones 2003; 12: 148-54) Keywords: LASIK, spherical equivalent, visual aquity

Corneal bed perforation by laser ablation during laser in situ keratomileusis

A 34-year-old man was referred to our department with corneal perforation after multiple laser in situ keratomileusis procedures for myopia. Corneal perforation occurred at the time of laser application during the fourth surgery, and the anterior chamber became completely flat. The perforation was sealed shortly thereafter and the corneal edema disappeared in 3 weeks, but there was an 86 μm forward shift of the cornea associated with an 8.0 diopter myopic shift during the subsequent 6 months. No further forward bulging of the cornea was observed. The refraction had stabilized up to 2 years postoperatively, but corneal irregular astigmatism limited the patient's best spectacle-corrected visual acuity.

Two-stage laser in situ keratomileusis to correct refractive errors after penetrating keratoplasty.

To evaluate the effect of a two-stage laser in situ keratomileusis (LASIK) procedure on eyes with high astigmatism and/or anisometropia after penetrating keratoplasty. Eleven postoperative penetrating keratoplasty eyes were included in a prospective, non-controlled study. All patients had at least 4.00 D of astigmatism and/or at least 3.00 D of anisometropia and were spectacle and contact lens intolerant. Two-stage LASIK was performed; in the first stage a hinged corneal flap 160 microm in thickness and 9 mm in diameter was created. After stabilization of corneal shape (1 to 3 months after keratotomy), the corneal flap was lifted and laser refractive treatment (second stage) was performed. After the first stage, a statistically significant reduction in refractive astigmatism (P<.01) was recorded. In all eyes but one, best spectacle-corrected visual acuity was maintained or improved after the procedure. Three months after the second stage, refractive astigmatism in 8 of 11 eyes (73%) was within +/- 1.00 D, and spherical equivalent refraction in 9 of 11 eyes (82%) was within +/- 1.00 D of intended correction. Preoperative irregular astigmatism persisted in three patients (3 eyes) who could not be corrected within +/- 1.00 D of refractive astigmatism and/or +/- 1.00 D of intended spherical equivalent refraction. In one eye, an interface infiltrate developed shortly after creation of the flap, and resulted in limited melting. A two-stage LASIK procedure improved visual acuity and refraction in postoperative penetrating keratoplasty eyes with high astigmatism and/or anisometropia. Complications were uncommon but can lead to loss of vision.

Inadvertent conjunctival trauma related to contact with drug container tips: A masquerade syndrome

Purpose To report the diagnosis, clinical course, and management of acute painful red eye syndrome associated with unintentional tube- or bottle-tip-induced conjunctival trauma. Design A small, noncomparative, interventional case series. Participants Twelve eyes of 12 patients (8 female and 4 male, aged 21–84 years) who were urgently reported or referred with a variety of diagnoses resulting from acute onset of red, painful eye. Four eyes had corneal transplants, two were recovering from herpetic keratitis, two had undergone cataract surgery or a laser in situ keratomileusis procedure, one had a corneal neurotrophic ulcer, and one used a contact lens. All the patients had received new medications (ophthalmic ointments in nine patients, topical drops in three patients) within 1 week before onset of symptoms. Intervention Assessment of method of self-administration of topical medication, evaluation of the ocular surface lesion, and patient education. Main outcome measures Association of patient behavior with ocular surface lesions. Results All 12 patients presented red, painful eyes, congested lower palpebral conjunctiva, epithelial conjunctival erosions, and episcleritis. In all patients, direct contact of the tube or bottle-tip with the affected area of the conjunctiva was ascertained by inspection. Instructions on proper method of drug administration and eye patching with lubrication were followed, within 2 weeks, by healing of conjunctival lesions. Conclusions Drug containers may cause nonintentional conjunctival trauma and simulate severe ocular disorders. Physicians should be aware of this diagnosis in any case of prolonged and unexplained ocular irritation and should instruct patients as to the proper instillation of topical ophthalmic medications.