Overnight Orthokeratology Research Articles

Bilateral Acanthamoeba Keratitis After Orthokeratology

To report bilateral Acanthamoeba keratitis after wearing an overnight reverse geometric contact lens for 5 days. Case report and review of the medical literature A 22-year-old woman developed bilateral corneal ulcers during orthokeratology. A slit-lamp examination showed round epithelial abrasion, radial infiltration, and disciform keratitis in both corneas. Visual acuity OD was hand motion and OS was counting fingers. Bilateral Acanthamoeba keratitis was diagnosed by culture by using non-nutrient agar overlaid with viable Escherichia coli. Small, round, and double-walled cysts were observed in non-nutrient agar under an inverted phase contrast microscope. Topical 0.02% polyhexamethylene biguanide, Cravit (0.5% levofloxacin), and Tobra (0.5% tobramycin) were administered. After 1 month of treatment, the corneal ulcer had healed, and the patient's best-corrected visual acuity was 20/100 OD and 20/25 OS. Acanthamoeba keratitis can simultaneously affect both eyes during overnight orthokeratology.

Orthokeratology Associated Microbial Keratitis

To report the clinical course, microbiologic findings, treatment, and outcomes of overnight orthokeratology associated microbial keratitis. Four cases of overnight orthokeratology associated microbial keratitis are reported. Four patients aged 14-23 years (mean 18 years) who had central or paracentral corneal ulcers were included. Visual acuity at presentation ranged from 20/30 to hand motion. In all cases Pseudomonas aeruginosa was cultured from corneal scrapings or storage solution. In all patients the infection resolved with intensive topical antimicrobial treatment. Final best-corrected visual acuity ranged from 20/25 to 20/200 according to the location, size, and density of the corneal scar, which complicated all cases. Infectious keratitis is a significant, visual threatening complication of overnight orthokeratology. Eye care practitioners should be aware of this complication and educate their patients of the importance of lens hygiene and prompt medical care when symptoms or signs of keratitis appear.

Recovery of corneal irregular astigmatism, ocular higher-order aberrations, and contrast sensitivity after discontinuation of overnight orthokeratology

Aims:To examine prospectively the recovery of various parameters after discontinuation of overnight orthokeratology.Methods:Seventeen subjects undergoing orthokeratology for 12 months were examined. Refraction, corneal topography, wavefront aberrometry, a visual acuity test...

Safety of Overnight Orthokeratology for Myopia: A Report by the American Academy of Ophthalmology

To review the published literature to evaluate the safety of overnight orthokeratology (OOK) for the treatment of myopia. Repeated searches of peer-reviewed literature were conducted in PubMed (limited to the English language) and the Cochrane Central Register of Controlled Trials (no language limitations) for 2005, 2006, and 2007. The searches yielded 495 citations. The panel reviewed the abstracts of these articles and selected 79 articles of possible clinical relevance for review. Of these 79 full-text articles, 75 were determined to be relevant to the assessment objective. No studies were rated as having level I evidence. Two premarket applications to the Food and Drug Administration were rated as having level II evidence. There were 2 studies rated as having level II evidence. The main source of reports of adverse events associated with OOK was 38 case reports or noncomparative case series (level III evidence). The prevalence and incidence of complications associated with OOK have not been determined. Complications, including more than 100 cases of infectious keratitis resulting from gram-positive and gram-negative bacteria and Acanthamoeba, have been described in case reports and case series representing observations in undefined populations of OOK users. Data collection was nonstandard. Risk factors for various complications cannot be determined. Because OOK puts patients at risk for vision-threatening complications they may not encounter otherwise, sufficiently large well-designed cohort or randomized controlled studies are needed to provide a more reliable measure of the risks of treatment and to identify risk factors for complications. Overnight orthokeratology for slowing the progression of myopia in children also needs well-designed and properly conducted controlled trials to investigate efficacy. Because of variations in orthokeratology practice, a wide margin of safety should be built into OOK regimens. Proprietary or commercial disclosure may be found after the references.

Reversibility of Effects of Orthokeratology on Visual Acuity, Refractive Error, Corneal Topography, and Contrast Sensitivity

To investigate the changes in corneal shape and optical performance during and after discontinuation of overnight orthokeratology for correction of myopia. Both eyes of 15 subjects were fitted with overnight reverse-geometry orthokeratology lenses, which were then worn for >4 hr overnight for 52 weeks. Subjects were free of ocular disease and had a corrected visual acuity of > or =1.0. Refractive correction, uncorrected visual acuity, corneal topography, and contrast sensitivity (at 4 spatial frequencies) were measured under photopic conditions. Refractive error (spherical equivalent) and contrast sensitivity were decreased, whereas uncorrected visual acuity, the surface asymmetry index, and the surface regularity index were increased, 1 week after the onset of overnight orthokeratology and remained so during the 52 weeks of treatment. These parameters had largely returned to baseline values by 8 weeks after treatment discontinuation. Overnight orthokeratology improved uncorrected visual acuity and reduced refractive error but increased corneal irregularity and impaired contrast sensitivity. However, these changes in visual function and corneal shape were reversed after discontinuation of orthokeratology lens wear.

Time Course of Changes in Ocular Higher-Order Aberrations and Contrast Sensitivity after Overnight Orthokeratology

To investigate prospectively the time course of changes in ocular higher-order aberration and contrast sensitivity after overnight orthokeratology. Data from 34 eyes of 17 patients who completed 1-year follow-up examinations were analyzed. The manifest refraction was -2.17 +/- 0.86 D at baseline. Ocular higher-order aberrations for a 4-mm pupil were measured, and the root-mean-square (RMS) of the third-, fourth-, and total higher-order aberrations were determined. Contrast sensitivity was assessed at four spatial frequencies, and the area under the log contrast sensitivity function (AULCSF) was calculated. These examinations were performed before and 1, 2, 3, 6, and 12 months after commencement of the procedure. The treatment significantly increased third-, fourth-, and total higher-order RMS (all P < 0.0001, paired t-test). Log contrast sensitivity significantly decreased at all four spatial frequencies, and AULCSF was also significantly reduced after the treatment (P < 0.0001). To assess the time course of changes in these parameters, posttreatment data were analyzed by using repeated-measures analysis of variance. There were no significant fluctuations in manifest refraction; uncorrected visual acuity; third-, fourth-, and total higher-order RMS; and AULCSF (all P > 0.05). In addition, there was no significant variance in log contrast sensitivity at each spatial frequency during the 1-year follow-up period (all P > 0.05). The initial reduction in optical quality of the eye and quality of vision after the procedure is stable during the treatment period of at least 1 year, and the reduction does not worsen further after 1 month. Orthokeratology candidates should be fully informed of these changes.

Histomorphometric Profile of the Corneal Response to Short-term Reverse-geometry Orthokeratology Lens Wear in Primate Corneas

To investigate the histological changes in primate cornea induced by short-term overnight orthokeratology (OK). Nine young adult primates were used. One animal served as negative control. The remaining 8 animals wore reverse-geometry OK lenses for periods of 4, 8, 16, and 24 hours on 1 eye with the other eye as control. Central and midperipheral corneal thickness, as well as ultrastructural changes in corneal epithelium, stroma and endothelium in response to OK lenses, were evaluated. OK significantly reduced the thickness of the central cornea in all treatment groups. The central corneal thinning was both stromal and epithelial in origin. Substantial midperipheral corneal thickening was seen in 16-hour and 24-hour lens-wear groups and this effect was both stromal and epithelial in origin as well. Histology evidence indicated the primary epithelial response in the central cornea was compression of cells that resulted in wing cells becoming shorter and basal cells being squatted rather than lost or migration of cell layers. These pronounced cell shape changes occurred without compromising the structural integrity of the desmosomes. The thickened corneal epithelium has normal cell layers. The squamous cells have larger surface sizes and are composed of oval instead of flattened nuclei. This implied delayed surface cell exfoliation at the thickened midperipheral epithelium. Physical presence of OK lens over the cornea did not influence the microstructures of microvilli and microplicae, endothelium, and collagen distribution. The primate cornea, particularly the corneal epithelium, responds rapidly to the application of reverse-geometry OK lenses with significant epithelial cell shape alterations with short-term OK lens wear. This finding suggests that the corneal epithelium is moldable in response to the physical forces generated by the OK lenses.

The validity of the Jessen formula in overnight orthokeratology: a retrospective study

To investigate the validity of the Jessen formula, with a compression factor of 0.75, in determining the back optic zone radius (BOZR) of an orthokeratology (ortho-k) lens for myopic reduction [i.e. BOZR = flattest K- (target reduction + 0.75)]. One hundred and twenty-three consecutive ortho-k patient files from the Optometry Clinic of The Hong Kong Polytechnic University were reviewed. Pertinent data at the preliminary visit and at the morning visit after 2 weeks of lens wear for 63 patients who fulfilled the inclusion criteria were retrieved for analysis. All patients were either fitted with DreimLens (DreimLens Taiwan, Taiwan Macro Vision Group, Taiwan, China) or eLens (E&E Optics Ltd., Hong Kong SAR, China) designs. Only data from the right eye were analysed. The validity of the Jessen formula was evaluated by comparing the equation of the plot of myopic reduction attempted (based on the Jessen formula) and myopic reduction achieved (based on subjective refraction). The Jessen formula was found to underestimate the intended target of myopic reduction following ortho-k. The results suggested that the formula should be revised to BOZR = flattest K- (1.23 target reduction + 1.27). If the intention is to overcorrect the ortho-k patient by 0.75 D to allow for regression during the daytime, the Jessen formula with a compression factor of 0.75 is not valid to determine the BOZR of the ortho-k lens designs.

Corneal foreign body injury during overnight orthokeratology lens wear: A case report

Purpose A case of asymptomatic corneal foreign body injury during orthokeratology lens wear is reported. Case report An 8-year-old Chinese female myopic child with 21 months of overnight orthokeratology lens wear experienced a corneal foreign body injury without symptoms. The foreign body was removed and the eye treated with prophylactic antibiotic and ocular lubricant. Orthokeratology treatment was resumed 4 weeks after initial detection and management and a small residual corneal scar remained. Discussion The mechanisms, differential diagnoses, management and role of neural sensitivity in corneal foreign body injury during orthokeratology lens wear are discussed. Clinicians should be aware that subtle corneal insult may be without symptoms during prolonged overnight orthokeratology lens wear.

Mesopic Contrast Sensitivity and Ocular Higher-Order Aberrations after Overnight Orthokeratology

To investigate mesopic contrast sensitivity and night driving ability in eyes undergoing overnight orthokeratology, and to analyze the relationship among mesopic contrast sensitivity, ocular higher-order aberrations, and myopic correction. Prospective, noncomparative, consecutive case series. In 44 eyes of 22 subjects (mean age +/- standard deviation [SD], 24.0 +/- 3.2 years) with orthokeratology, ocular aberrations and mesopic contrast sensitivity were determined before and three months after commencement of the procedure. Mean spherical equivalent refraction +/- SD was -2.34 +/- 0.99 diopters at baseline. Mesopic contrast sensitivity with and without glare was assessed using the Mesotest II (Oculus, Wetzlar, Germany). Orthokeratology significantly reduced the log mesopic contrast sensitivity from 0.25 +/- 0.08 to 0.08 +/- 0.10 without glare (P < .0001, Wilcoxon) and from 0.21 +/- 0.11 to 0.07 +/- 0.10 with glare (P < .0001). The proportion of eyes that fulfilled the German standard recommendation level for night driving was 36%. The induced changes in log mesopic contrast sensitivity showed significant negative correlation with the changes in third-order (r = -0.490, P = .0013 without glare; r = -0.362, P = .0177 with glare; Spearman rank correlation coefficient) and fourth-order root mean square (r = -0.586, P = .0001 and r = -0.306, P = .0450, respectively). Furthermore, significant correlation was found between the amount of myopic correction and the induced changes in log mesopic contrast sensitivity (r = -0.442, P = .0038 without glare; r = -0.464, P = .0024 with glare). The induced changes in higher-order aberrations significantly correlated with the amount of myopic correction (P < .0001, Pearson correlation coefficient). Mesopic contrast sensitivity after overnight orthokeratology is deteriorated significantly as ocular higher-order aberrations increase, and these changes depend on the amount of myopic correction.

Changes in the Anterior and Posterior Radii of the Corneal Curvature and Anterior Chamber Depth by Orthokeratology

To investigate the mechanism of the refractive effect of orthokeratology by using measurements of the anterior and posterior radii of the corneal curvature and anterior chamber depth with a Pentacam analysis system. Nine women (18 eyes) with a mean age of 29.6+/-3.8 years and low to moderate myopia (<or=-4.00 diopters [D]) were recruited for a 53-week trial of overnight orthokeratology using RD171K lenses (hexafocon A). After wearing the orthokeratology lenses overnight, subjects were examined during the day. With a Pentacam analysis system, subjects were examined at 2, 4, 8, 12, 24, 36, and 53 weeks for the assessment of the anterior and posterior radii of the corneal curvature and anterior chamber depth. Myopic refractive error significantly reduced during the trial (P<0.001, analysis of variance). The mean refractive error was -2.85+/-0.46 D at baseline and significantly reduced to -0.28+/-0.65 D at 2 weeks (P<0.01, Bonferroni-Dunn post hoc test). At any week, no significant differences were seen in the central posterior radius of the corneal curvature (P=0.55, analysis of variance) or the anterior chamber depth (P=0.69, analysis of variance). The amount of change in the central anterior radius of the corneal curvature significantly correlated with the change in refractive error at 24 weeks (r=0.57, P<0.05, Pearson correlation coefficient). Overnight orthokeratology lens wear alters the anterior corneal shape rather than the posterior radius of the corneal curvature and the anterior chamber depth. This finding suggests that the primary factor in the refractive effect of orthokeratology is change in the anterior corneal shape rather than overall corneal bending.

Stability of Wavefront Aberrations During the Daytime After 6 Months of Overnight Orthokeratology Corneal Reshaping

To evaluate the stability of wavefront aberrations during the daytime after 6 months of overnight orthokeratology corneal reshaping. A prospective study of 26 eyes using the Ultravision BE lens design during 6 months of overnight wear. Uncorrected visual acuity (UCVA), cycloplegic refraction, and wavefront aberrometry were measured at 8 AM (within 1 hour after awakening and removing lenses), 1 PM (5 to 6 hours after lens removal), and 6 PM (10 to 12 hours after lens removal). There was no significant difference in UCVA between 8 AM, 1 PM, and 6 PM (P=.383). Spherical power from wavefront aberrometry showed significant regression from 8 AM to 1 PM (P<.001) and stabilized near zero diopters. Total root-mean-square (RMS) increased and higher order aberration RMS and defocus (Z4) decreased between 8 AM and 1 PM (P<.001) but did not change for the rest of the day (P>.001). There was no statistically significant change in astigmatism (Z3 and Z5) (P=.449) and coma (Z7 and Z8) (P=.145) between 8 AM, 1 PM, and 6 PM. Spherical aberration (Z12) showed regression throughout the day (P<.001). After 6 months of overnight orthokeratology wear, some optical aberrations showed regression during the day. Despite no significant change in UCVA during 10 to 12 hours, there was a significant increase in defocus (Z4) within the first 5 hours after removing the orthokeratology lens and a decrease in spherical aberration (Z12) throughout the day.

Good Visual Outcome After Prompt Treatment of Acanthamoeba Keratitis Associated With Overnight Orthokeratology Lens Wear

To describe a patient with a good visual outcome after prompt treatment of Acanthamoeba keratitis as a complication of overnight orthokeratology lens wear. Interventional case report. A 9-year-old boy experienced pain, photophobia, and redness in his right eye 3 days after visiting a swimming pool. He had been wearing overnight orthokeratology lenses for 5 months for the correction of moderate myopia in both eyes. On examination, best-corrected visual acuity in the right eye was 20/40. A diagnosis of Acanthamoeba keratitis with the presence of the classic feature of perineural infiltrates was made. The patient responded well to treatment with polyhexamethylene biguanide and propamidine isethionate (Brolene). Culture of corneal scrapings and contact lens solution showed heavy growth of Acanthamoeba. Treatment was tapered gradually during the next 4 months, and the final best-corrected visual acuity was 20/25. Acanthamoeba keratitis may be a vision-threatening complication associated with overnight orthokeratology lens wear. It is essential for eye care professionals to fully explain and warn parents of the potential downsides that may be associated with orthokeratology. Ophthalmologists should have a high level of suspicion of this complication because prompt diagnosis and treatment can result in good visual outcome.

Orthokeratology-Related Infectious Keratitis: A Case Series

To describe five patients who developed infectious keratitis after the use of overnight orthokeratology contact lenses. Retrospective case report of five patients with infectious keratitis seen in Singapore National Eye Centre between 2001 and 2006. Five children between the ages of 9 and 14 years, who wore their lenses for an average of 1.5 months before developing orthokeratology-related infectious keratitis, were seen and treated at the Singapore National Eye Centre. All five patients had cultures that were positive for Pseudomonas aeruginosa. They were treated with fortified cefazolin (50 mg/mL) and gentamicin (14 mg/mL) and responded well, with resolution of the infectious keratitis. Although most patients had a best-corrected visual acuity of 20/40 or better after the resolution of the acute infection, they all showed a central or paracentral residual scar. Because of the safety issues involved, orthokeratology should be used with caution in children.

Stromal response to orthokeratology: an X‐ray diffraction study

Abstract Purpose: To examine the impact of overnight orthokeratology lens wear on stromal collagen fibril diameter and spacing using synchrotron X‐ray diffraction. Methods: Seven New Zealand White rabbits (10 eyes) wore orthokeratology lenses (Capricornia, Brisbane, Australia) overnight during a 2‐week period to determine the effect of corneal refractive therapy on stromal collagen fibrils. To verify the effectivity of treatment, corneal topography (Medmont, Brisbane, Australia), corneal thickness (Allergan Humphrey pachymetry) and refractive error (retinoscopy) were measured prior to and every 3‐4 days during the treatment period. Following completion of treatment, rabbits were euthanased and corneas immediately dissected and snap frozen for subsequent X‐ray diffraction analysis every 1mm over the central c.10mm horizontal corneal band. Results: Orthokeratology treatment induced an average change in refraction of 2.0 +/‐ 1.3DS, and a topography‐measured treatment zone diameter of 4.2 +/‐ 0.7mm. The results from X‐ray diffraction revealed no significant difference in collagen fibril diameter between treated and untreated eyes (p&gt;0.05). Interfibrillar spacing (IFS) was positively correlated with tissue hydration but no significant association between the change in IFS and refraction was apparent. Conclusions: The magnitude and time course of refractive change induced by orthokeratology in the rabbit eye is similar to that reported in humans, producing significant rapid and characteristic changes in corneal topography. Such specific changes in topography seem limited to the epithelial layers, with no parallel topographic modification evident in the underlying stromal architecture.

Good clinical practice in orthokeratology

Overnight orthokeratology is becoming more and more popular especially in the Asia-Pacific region where the treatment is primarily used for myopic control in young children. Risk of complications in contact lens wear increases during overnight wear and may further increase when the treatment is used on children. The aim of this paper is to provide a comprehensive guideline for practitioners to improve their orthokeratology practice and minimize unnecessary or preventable complications. The fundamental requirement for starting an orthokeratology practice is to have proper education in the area and to equip the practice appropriately. Overnight trial fitting is recommended to confirm the physiological response prior to commencement of the treatment. Practitioners should provide adequate information, both oral and written, to patients before and after the commencement of treatment to avoid any legal dilemmas and to improve patients' compliance. Costs for the treatment should be transparent and provision of an emergency contact number is a must. Patients should be regularly recalled for aftercare visits and all communication with patients should be properly documented. In this paper, patient selection and the clinical procedures were discussed and a standard of practice in orthokeratology proposed. We believe that the key to providing a safe orthokeratology practice is to continually update knowledge in the field, and to practice to the highest professional standards.

Fibrillary lines in overnight orthokeratology

This case report describes the appearance of fibrillary lines in the anterior stroma of a 39‐year‐old Asian woman wearing overnight orthokeratology (OK) lenses. The fibrillary lines were fine, slightly curved and sub‐epithelial, arranged in a band‐like annulus in the corneal mid‐periphery. The lines were not associated with epithelial staining, although a marked Fischer‐Schweitzer corneal mosaic was noted after blinking. Fibrillary lines are a relatively common finding in normal and keratoconic corneas and have been reported previously accompanying OK lens wear. Their origin is unknown and epithelial neural remodelling, corneal biomechanical stress and abrupt corneal curvature changes have been suggested as contributing factors. The appearance of fibrillary lines in our OK patient had no adverse consequences on vision or ocular health, at least in the medium term.

Safety and efficacy of overnight orthokeratology in myopic children

Background This prospective case series was conducted to describe the safety and efficacy of orthokeratology with the Emerald™ Contact Lens for Overnight Orthokeratology (Oprifocon A; Euclid Systems Corporation, Herndon, Virginia) among young myopes. Methods Twenty subjects (ages 10 to 16) were enrolled in the 6-month pilot study. Subjects were fit empirically with overnight orthokeratology lenses and evaluated at 1 day, 1 week, 1 month, 2 months, 3 months, and 6 months. Results Sixteen subjects completed the study. The mean baseline spherical equivalent refraction (SER) was −2.06 diopters (D) (±0.75). The mean SER at 6 months was −0.16 D (±0.38). The mean baseline uncorrected acuity was 0.78 (±0.28) logarithmic minimum angle of resolution (logMAR) equivalent (20/100 Snellen). The mean logMAR equivalent at 6 months was −0.03 ± 0.12 (<20/20 Snellen). On average, 40% of eyes showed some type of corneal staining between the 1-week and 6-month visits. No serious adverse events occurred during the study. Conclusions In contrast to previously published studies that reported maximum results at 2 weeks, subjects reached maximum reduction in myopia at the 1-week visit and, on average, obtained a 92.2% reduction in spherical equivalent refractive error at 6 months. This pilot study lends to a growing body of evidence that short-term correction of mild to moderate myopia with overnight orthokeratology is safe and efficacious in children and adolescents.

Gas Permeable (GP) Versus Non-GP Lens Wearers: Accuracy of Orthokeratology in Myopia Reduction

The primary objective of this study is to determine whether there are significant differences in visual and refractive outcomes between gas permeable (GP) and non-GP wearers following a 1-month period of overnight orthokeratology (OK). The study included 14 subjects between the ages of 18 and 42 years. Group 1 consisted of six subjects wearing GP lenses for the correction of myopia for, at minimum, 1 year. Group 2 consisted of eight subjects wearing soft contact lenses or spectacles for the correction of myopia. All subjects were fit into the BE design in Boston XO material and lenses were worn for a period of 1 month. Unaided visual acuity using high (90%) and low (10%) contrast log MAR Bailey-Lovie vision charts, subjective refraction, corneal topography, and slit lamp evaluation were performed. Subjects were evaluated at day 1, 7, 14, 21, and 30. One eye of each subject was considered for analysis; the eye with the better response was chosen based on post-OK measures. The mean post-OK spherical equivalent was 0.29 +/- 0.55 D in the GP group and 0.37 +/- 0.46 D in the non-GP group; the difference was statistically significant (p = 0.03). Baseline astigmatism decreased in the non-GP group after OK while there was no significant change in the GP group. The mean high contrast acuities were 0.06 +/- 0.12 in the GP group and 0.17 +/- 0.07 in the non-GP group (p = 0.05), whereas the low contrast acuities were 0.18 +/- 0.17 in the GP and 0.02 +/- 0.09 in the non-GP group (p = 0.01). Although the non-GP group has higher post-OK visual acuity and spherical equivalent statistically, the GP group has attained an average unaided acuity of >20/20 and residual myopia <0.5 D. Clinically, this shows that OK can be a promising technique in GP wearers.

Pediatric Microbial Keratitis in Taiwanese Children

To study the clinical and microbiological characteristics of pediatric microbial keratitis in Taiwan. The medical records of 81 eyes with microbial keratitis in 78 children aged 16 years or younger who were diagnosed and treated at Chang Gung Memorial Hospital, Taipei, Taiwan, from July 1, 1998, through December 31, 2002, were retrospectively reviewed. Predisposing factors, microbial culture results, clinical course, and visual outcomes were analyzed. Predisposing factors were contact lens wear (33 cases [40.7%]), trauma (17 cases [21.0%]), ocular disease (12 cases [14.8%]), and systemic disease (9 cases [11.1%]). Eight of the 33 contact lenses were rigid gas-permeable lenses that were worn overnight for orthokeratology. Forty-seven (58.0%) of the 81 eyes were culture positive. The most common isolates were Pseudomonas aeruginosa (21 eyes [44.7%]) and Staphylococcus aureus (9 eyes [19.1%]). Twelve (14.8%) of the 81 eyes required surgical intervention. Of the 68 eyes that had a best-corrected visual acuity available at the last follow-up, 33 eyes achieved best-corrected visual acuity of 20/25 or better. Predisposing factors for pediatric infectious keratitis vary with age. In the teenage years, the most predominant risk factor is contact lens wear. Infectious keratitis resultant from overnight orthokeratology lenses should receive particular attention. Parents of children who consider overnight orthokeratology should evaluate the benefit of temporary myopia reduction and the risk of infection. Identification of predisposing factors and microorganisms may be helpful for early recognition and treatment of pediatric microbial keratitis.