Topical Solution for Retinal Delivery: Bevacizumab and Ranibizumab Eye Drops in Anti-Aggregation Formula (AAF) in Rabbits.

PURPOSE: Wet age-related macular degeneration (AMD) is a blinding retinal disease. Monthly intravitreal anti-VEGF antibody injections of bevacizumab (off-label) and ranibizumab (FDA approved) are the standard of care. Antibody aggregation may interfere with ocular absorption/distribution. This study assessed topical delivery of dilute antibodies to the posterior segment of rabbit eyes using a novel anti-aggregation formula (AAF). METHODS: Bevacizumab, or biosimilar ranibizumab was diluted to 5 mg/ml in AAF. All rabbits were dosed twice daily. Substudy 1 rabbits (bevacizumab, 100 µl eye drops): Group 1 (bevacizumab/AAF, n = 6); Group 2 (bevacizumab/PBS, n = 7) and Vehicle control (AAF, n = 1). Substudy 2 rabbits (ranibizumab biosimilar/AAF, 50 µl eye drops): (ranibizumab biosimilar/AAF, n = 8). At 14.5 days, serum was drawn from rabbits. Aqueous, vitreous and retina samples were recovered from eyes and placed into AAF aliquots. Tissue analyzed using AAF as diluent. RESULTS: Bevacizumab in AAF permeated/accumulated in rabbit aqueous, vitreous and retina 10 times more, than when diluted in PBS. AAF/0.1% hyaluronic acid eye drops, dosed twice daily, provided mean tissue concentrations (ng/g) in retina (29.50), aqueous (12.34), vitreous (3.46), and serum (0.28 ng/ml). Additionally, the highest concentration (ng/g) of ranibizumab biosimilar was present in the retina (18.0), followed by aqueous (7.82) and vitreous (1.47). Serum concentration was negligible (< 0.04 ng/ml). No irritation was observed throughout the studies. CONCLUSIONS: Bevacizumab and ranibizumab, in an AAF diluent eye drop, can be delivered to the retina, by the twice daily dosing of a low concentration mAb formulation. This may prove to be an adjunct to intravitreal injections.

Bluetooth Noise-Canceling Headphones Improve the Quality of Ophthalmic Exams in Patients With Hearing Loss: A Randomized Controlled Trial.

INTRODUCTION: This study tests the utilization of Bluetooth noise-canceling headphones in improving the quality of eye exams in patients with hearing loss. This prospective study was approved on ethical standards by the University of Texas Medical Branch (UTMB) Institutional Review Board (Approval No. 22-0079) and registered with the National Institutes of Health (NCT05420038). METHODS: UTMB patients above 55 years of age were screened for hearing loss using soundcheck audiometry. Twenty-nine subjects answered pre-recorded ophthalmic exam questions that solicited precise responses. As controls, subjects were randomly administered half of the questions via headphones and half via a smartphone at normal speech volume (60 decibels). Points were awarded for responses demonstrating comprehension, and a post-exam survey was collected. RESULTS: Collectively, the mean score was 1.79 with headphones versus 0.96 with control on the Amsler grid segment and 1.90 with headphones versus 0.97 with control on education questions (p=0.001). Between red zone and yellow zone hearing loss patients, the more severe red zone group answered significantly better in both Amsler (1.78 versus 0.50; p=0.0003) and education questions (1.88 versus 0.44; p<0.0001) with headphones. The yellow zone group answered better with headphones overall but failed to reach significance. Post-exam survey indicated that 28 of 29 patients (97%) preferred the headphones during ophthalmic exams. CONCLUSION: Patients with hearing loss demonstrated better comprehension with Bluetooth headphones. These low-cost devices show great promise at improving effective, compassionate communication between providers and hearing loss patients.

Racial Disparities in Cataract Surgery Timeline and Intraocular Lens Selection: A Retrospective Study.

Purpose: There is a significant amount of literature focusing on racial inequities in utilization rates and intraoperative complications of cataract surgery. Unfortunately, little is known about racial disparities regarding the timeline of cataract surgery and intraocular lens (IOL) selection. This study investigated whether black patients have a different preoperative and postoperative cataract surgery timeline and IOL selection than white patients. Methods: A total of 10,235 patients (83.47% white) were retrospectively identified from a tertiary academic center who underwent cataract surgery between 2015 and 2022. Each patient's best corrected visual acuity (BCVA), slit lamp findings, and surgical timeline were recorded. IOL selection was categorized as standard or premium. Results: Black patients had significantly worse mean ± SD preoperative logMAR BCVA than white patients (0.47 ± 0.55 vs. 0.58 ± 0.70, respectively; P = 0.0117) and were significantly less likely to receive surgery within 120 days of referral (RR, 0.71 [95% confidence interval {CI}, 0.64-0.79]; P < 0.0001). White patients were 25%, 24%, and 29% less likely to follow-up than black patients at postoperative day 1, day 7, and day 30, respectively (P < 0.0001). White patients were 6.09 (95% CI, 3.49, 10.63) times more likely to receive a premium IOL compared to black patients (P < 0.0001). Conclusions: Black patients experienced more delays with receiving cataract surgery but are more adherent with postoperative follow-up. Black patients were far less likely to receive a premium IOL than white patients. Translational Relevance: Increased awareness of racial inequities in cataract surgery may improve the delivery of eye care to minority groups.

CXCR3 deletion aggravates corneal neovascularization in a corneal alkali-burn model.

Corneal neovascularization can cause devastating consequences including vision impairment and even blindness. Corneal inflammation is a crucial factor for the induction of corneal neovascularization. Current anti-inflammatory approaches are of limited value with poor therapeutic effects. Therefore, there is an urgent need to develop new therapies that specifically modulate inflammatory pathways and inhibit neovascularization in the cornea. The interaction of chemokines and their receptors plays a key role in regulating leukocyte migration during inflammatory response. CXCR3 is essential for mediating the recruitment of activated T cells and microglia/macrophages, but the role of CXCR3 in the initiation and promotion of corneal neovascularization remains unclear. Here, we showed that the expression of CXCL10 and CXCR3 was significantly increased in the cornea after alkali burn. Compared with WT mice, CXCR3-/- mice exhibited significantly increased corneal hemangiogenesis and lymphangiogenesis after alkali burn. In addition, exaggerated leukocyte infiltration and leukostasis, and elevated expression of inflammatory cytokines and angiogenic factor were also found in the corneas of CXCR3-/- mice subjected to alkali burn. With bone marrow (BM) transplantation, we further demonstrated that the deletion of CXCR3 in BM-derived leukocytes plays a key role in the acceleration of alkali burn-induced corneal neovascularization. Taken together, our results suggest that upregulation of CXCR3 does not exhibit its conventional action as a proinflammatory cytokine but instead serves as a self-protective mechanism for the modulation of inflammation and maintenance of corneal avascularity after corneal alkali burn.

Blepharoconjunctivitis and Otolaryngological Disease Trends in the Context of Mask Wearing during the COVID-19 Pandemic.

(1) Purpose: In 2020, wearing of face masks was mandated in the United States in an effort to lessen transmission of the novel 2019 coronavirus disease (COVID-19) pandemic; however, long-term mask wearing may present with unintended side-effects in both ophthalmic and otolaryngologic clinical practice. This study aims to examine if mask wearing increased the incidence of primarily chalazion, blepharoconjunctivitis, and rhinitis occurrence during the mask-mandated COVID-19 pandemic period. (2) Methods: Medical records from tertiary academic center clinics were analyzed for incidence of ophthalmic and otolaryngologic diagnoses of interest (blepharoconjunctivitis- and rhinitis-related disorders). Data were collected from a pre-pandemic (March 2019-February 2020) and a mid-pandemic window (March 2020-February 2021) during which widespread mask mandates were implemented in Texas. Comparison was performed using a t-test analysis between incidence of chosen diagnoses during the described time periods. (3) Results: Incidence of ophthalmic disorders (primarily blepharoconjunctivitis and chalazion) in the pre-pandemic versus mid-pandemic windows did show a significant difference (p-value of 0.048). Similarly, comparison of otolaryngologic diagnoses (primarily rhinitis and related conditions) between the two time periods showed a significant difference (p-value of 0.044) as well. (4) Conclusion: Incidence of the chosen ophthalmic and otolaryngologic disorders did increase during periods of mask mandates. While these findings are preliminary, further studies are warranted to understand other factors that may have played a role in eye and nose pathology.

Concentration-associated pathology of alkali burn in a mouse model using anterior segment optical coherence tomography with angiography.

Pathological features of alkali concentration-associated burn were studied using non-invasive anterior segment optical coherence tomography (AS-OCT) and OCT angiography (OCTA). Alkali burn was induced in C57BL/6J mice (n = 20) by placing filter paper soaked in 0.1, 0.25, 0.5, and 1 M NaOH for 30s on the right eye (left eye control). Longitudinal imaging was performed with AS-OCT/OCTA and fluorescein angiography over 14 days, after which eyes were enucleated at 7 and 14 days for histology and immunofluorescence. Concentration-associated corneal swelling was maximal at 0.5M, increasing linearly in a concentration-dependent fashion at 0.1, 0.25, and 0.5 M NaOH, to levels of 50%, 100%, and 175% of control, respectively. At 0.1M, corneal swelling and surface erosions were prominent, while at 0.25M, deep tissue damage, limbal neovascularization, and stromal haze were evident at 7 days. At 0.5M and 1M, severe exacerbation of the corneal swelling, angle closure, Descemet's membrane detachment, hyphema, and profuse central neovascularization were noted as early as day 3, which further progressed to inflammation, fibrosis, and opacity by day 7. We conclude that alkali concentration-dependent burn intensity biomarkers can be assessed by non-invasive AS-OCT/OCTA, distinguishing between mild, moderate, and severe ocular injury, with potential relevance toward clinical utilization in human eyes.

Tauopathy induces degeneration and impairs regeneration of sensory nerves in the cornea.

The cornea is transparent and innervated by a dense collection of sensory nerves originating from the ocular branch of the trigeminal nerve. This study was designed to comprehensively analyze alterations of corneal sub-basal nerve plexus in a mouse model of tauopathy (P301L transgenic mice) to test the possibility of using corneal nerves as a biomarker for tauopathy. Corneal sensitivity, thickness and epithelial wound healing were measured non-invasively by aeshesiometer, optical coherence tomography and fluorescein staining, respectively. Tau, corneal nerves and immune cells were examined by immunohistochemistry or Western blot. At the early stage of tauopathy, although corneal sensitivity, thickness and nerve fiber density were not greatly altered, corneal nerve abnormalities were observed in the peripheral region of young P301L mice. With aging, the density of abnormal nerves increased, while corneal sensitivity, epithelial thickness, nerve fiber density and length decreased in middle-aged P301L mice compared with WT mice. After corneal epithelial injury in young mice, no difference in reepithelialization was observed between two groups of mice, however, the regeneration of corneal nerves in P301L mice lagged behind WT mice, which was reflected by delayed recovery of corneal sensitivity, decreased corneal nerve density and length and density of CD45+ dendriform cells in P301L mice. In conclusion, our data provide compelling evidence that corneal nerves were changed in a mouse model of tauopathy in an age-dependent manner. Moreover, tau overexpression impairs corneal nerve regeneration. These results suggest that cornea may serve as a promising ocular site for the early diagnosis of tauopathy.

Longitudinal Assessment of Alkali Injury on Mouse Cornea Using Anterior Segment Optical Coherence Tomography.

Purpose: Chemical burns due to alkalis cause extensive damage to the ocular surface leading to blindness. Assessment of ocular burn could be challenging due to severe opacity, inflammation, and angiogenesis. Anterior segment optical coherence tomography (AS-OCT) and OCT angiography (OCTA) may provide fast, non-invasive deep tissue visualization of pathology with high sensitivity in conjunction with slit-lamp analysis. Methods: C57-BL/6J mice were anesthetized with ketamine/dexmedetomidine, and corneal alkali burn was induced (n = 6) by placing filter paper soaked in 1-M sodium hydroxide for 30 seconds on the right eye while the left eye was kept as control. Longitudinal imaging was done with AS-OCT/OCTA and fluorescein angiography at various time intervals for 14 days. Results: AS-OCT showed characteristic pathological changes in alkali-burned eyes with high sensitivity. Although OCT/OCTA showed three-dimensional and cross-sectional views of the anterior chamber and angiogenesis, fluorescein angiography showed nascent vessels with active leakage. Corneal swelling progressively increased by 125.26% on day 12 with a high prevalence of epithelial bullae, stromal cysts, stromal splitting, and Descemet's membrane detachment. Neovascularization was noted as early as day 4 in the burned eyes by both methods. Severe corneal opacity and anterior chamber inflammation were also detected by AS-OCT/OCTA. Conclusions: AS-OCT/OCTA is a promising, noninvasive, high-resolution imaging modality that can provide both qualitative and quantitative information regarding deep tissue pathology at a structural level. Translational Relevance: Noninvasive AS-OCT/OCTA and fluorescein methods show promise in clinical pathology evaluation for ocular injury management and prognostic indications, as the early presence of Descemet's membrane detachment and corneal swelling appears to be correlated with the severity and localization of corneal neovascularization.

Fishhook Injury of the Anterior Chamber Angle of the Eye.

A 36-year-old man presented with a corneal penetrating fishhook injury with the tip embedded in the inferior anterior chamber angle of the eye. Complete removal was achieved with extension of the wound at the limbus using the "cut-out" technique. Intraocular fishhook injuries are common in fishing communities and effective surgical removal may involve modified techniques previously described for skin or mucosal tissue.

Use and misuse of cosmetic contact lenses among US adolescents in Southeast Texas.

BACKGROUND: Cosmetic contact lenses (CCL) are popular among adolescents, but incorrect use can harm the eye. METHODS: This study assessed CCL hygiene behaviors among adolescents attending a Texas pediatric clinic. Anonymous surveys about CCL hygiene practices were administered to adolescents 13-18 years old. RESULTS: We found that 14% (53/392) of respondents had worn CCL, of which 83% were females. Over 70% reported first use at <15 years old. Knowledge about CCL was low and two-thirds of users had not been instructed on proper care. More than half stored them in water and did not rinse them with contact solution after removal. Over one-third wore CCL >8 hours/day. Moreover, 15% of CCL users reported borrowing someone else's CCL. Complications resulting from wearing CCL were common. CONCLUSION: This study highlights poor CCL hygiene among adolescents. These data demonstrate the need to develop interventions to educate adolescents on proper care and risks associated with CCLs.

Knowledge and Use of Cosmetic Contact Lenses Among Reproductive-Age Women.

OBJECTIVES: To assess use, knowledge, and complications of cosmetic contact lenses (CCLs) among women of reproductive age. METHODS: A cross-sectional, anonymous self-administered survey assessing cosmetic or decorative contact lens knowledge and experiences was completed by 686 women in Texas in 2017. Main outcome measures were use, knowledge, and associated complications. RESULTS: Almost 1 in 4 women (164/686) reported prior use of CCLs and most had worn the lenses >3 times. Women born in the United States, who knew someone who wore cosmetic lenses, or had visited an eye doctor in the past year were more likely to have used CCLs. Knowledge scores were low and the majority of cosmetic lens users experienced complications (61%). The most frequently reported complications were eye pain and discomfort (35%); itchy, watery eyes (34%); and red, swollen eyes (28%). Borrowing lenses was significantly associated with medical complications (88% of borrowers reported complications). Among 18 respondents who sought medical attention for a CCL-related problem, only 11% obtained care within 24 hours. Few participants had discussed CCL use with an eye doctor in the past year. CONCLUSIONS: Many U.S. women have used CCLs obtained from unauthorized sources. Knowledge of safe practices is very limited and most users develop complications. Interventions are needed to educate the public about the risk of CCL use to reduce adverse outcomes.

Formulation Stabilization and Disaggregation of Bevacizumab, Ranibizumab and Aflibercept in Dilute Solutions.

PURPOSE: Studies were conducted to investigate dilute solutions of the monoclonal antibody (mAb) bevacizumab, mAb fragment ranibizumab and fusion protein aflibercept, develop common procedures for formulation of low concentration mAbs and identify a stabilizing formulation for anti-VEGF mAbs for use in in vitro permeation studies. METHODS: Excipient substitutions were screened. The most stabilizing formulation was chosen. Standard dilutions of bevacizumab, ranibizumab and aflibercept were prepared in PBS, manufacturer's formulation, and the new formulation. Analysis was by SE-HPLC and ELISA. Stability, disaggregation and pre-exposure tests were studied. RESULTS: When Avastin, Lucentis and Eylea are diluted in PBS or manufacturer's formulation, there is a 40-50% loss of monomer concentration and drug activity. A formulation containing 0.3% NaCl, 7.5% trehalose, 10 mM arginine and 0.04% Tween 80 at a pH of 6.78 stabilized the mAbs and minimized the drug loss. The formulation also disaggregates mAb aggregation while preserving the activity. Degassing the formulation increases recovery. CONCLUSIONS: We developed a novel formulation that significantly stabilizes mAbs under unfavorable conditions such as low concentration or body temperature. The formulation allows for tissue permeation experimentation. The formulation also exhibits a disaggregating effect on mAbs, which can be applied to the manufacture/packaging of mAbs and bioassay reagents.

Photokinetic Drug Delivery: Near infrared (NIR) Induced Permeation Enhancement of Bevacizumab, Ranibizumab and Aflibercept through Human Sclera.

PURPOSE: Permeation studies, with near infrared (NIR) light and anti-aggregation antibody formulation, were used to investigate the in vitro permeation of bevacizumab, ranibizumab and aflibercept through human sclera. METHODS: A vertical, spherical Franz cell diffusion apparatus was used for this scleral tissue permeation model. A photokinetic ocular drug delivery (PODD) testing device accommodated the placement of NIR LEDs above the donor chambers. An adjustable LED driver/square wave generator provided electrical energy with a variable pulse rate and pulse width modulation (duty cycle). RESULTS: Exposure to non-thermal NIR light had no effect on mAbs with regard to monomer concentration or antibody binding potential, as determined by SE-HPLC and ELISA. The optimal LED wavelength was found to be 950 nm. Duty cycle power of 5% vs 20% showed no difference in permeation. When compared to controls, the combination of non-aggregating antibody formulation and NIR illumination provided an average transscleral drug flux enhancement factor of 3X. CONCLUSION: Narrow wavelength incoherent (non-laser) light from an NIR LED source is not harmful to mAbs and can be used to enhance drug permeation through scleral tissue. The topical formulation, combined with pulsed NIR light irradiation, significantly improved scleral permeation of three anti-VEGF antibody drugs.

Laser in situ keratomileusis versus lens-based surgery for correcting residual refractive error after cataract surgery.

PURPOSE: To evaluate and compare the efficacy and safety of laser in situ keratomileusis (LASIK) versus lens-based surgery (intraocular lens [IOL] exchange or piggyback IOL) for correcting residual refractive error after cataract surgery. SETTING: Private eye center, Salt Lake City, Utah, USA. METHODS: This retrospective study included 57 eyes of 48 patients who had LASIK (28 eyes) or lens-based correction (29 eyes) for residual refractive error after cataract surgery. The visual and refractive outcomes were evaluated at a mean follow-up of 20 to 24 months. RESULTS: In the LASIK group, the mean spherical equivalent (SE) was reduced from -1.62 +/- 0.80 diopters (D) preoperatively to +0.05 +/- 0.38 D postoperatively in myopic eyes and from +0.51 +/- 1.25 D to +0.19 +/- 0.35 D in hyperopic eyes. Ninety-two percent of eyes were within +/-0.50 D of intended correction. In the lens group, the mean SE was reduced from -3.55 +/- 2.69 D preoperatively to -0.20 +/- 0.50 D postoperatively in myopic eyes and from +2.07 +/- 2.38 D to +0.07 +/- 0.85 D in hyperopic eyes. Eighty-one percent of eyes had postoperative SE within +/-0.50 D of the intended correction. The UCVA improved significantly in both groups. No eye lost more than 1 line of BSCVA. With a similar length of follow-up, no significant difference in postoperative SE was found between the 2 groups (P = .453). CONCLUSIONS: The results showed efficacy, safety, predictability, and merits of LASIK and lens-based approaches for correcting different types of residual refractive error after cataract surgery.

Laceration and partial dislocation of LASIK flaps 7 and 4 years postoperatively with 20/20 visual acuity after repair.

PURPOSE: To report two cases of late ocular trauma resulting in laceration of corneal flaps 7 and 4 years (cases 1 and 2, respectively) after LASIK. METHODS: A 49-year-old man sustained laceration of the flap and interface foreign body debris from construction material in the right eye 7 years after uneventful LASIK (case 1). A 33-year-old man had partial dislocation of the flap 4 years after LASIK in the left eye (case 2) due to a penetrating wood chip accident. Surgical procedures were performed to remove the foreign bodies and reposition the flaps. RESULTS: In case 1, postoperative uncorrected visual acuity (UCVA) was 20/25 with manifest refraction of -0.50 -0.50 x 110 corrected to 20/20. In case 2, UCVA was 20/20 with piano refraction after LASIK retreatment. CONCLUSIONS: Corneal LASIK flaps are susceptible to penetrating trauma, which can occur >7 years after the procedure. Proper everamanage ment of the trauma and LASIK flap can restore excellent visual acuity.

Retreatment after wavefront-guided and standard myopic LASIK.

PURPOSE: To assess and compare the clinical outcomes of conventional LASIK retreatments after primary wavefront-guided and standard myopic LASIK. DESIGN: Retrospective review of interventional case series. PARTICIPANTS: One hundred fifty-four eyes of 114 consecutive patients underwent a conventional LASIK retreatment after previous wavefront-guided and standard myopic LASIK. The eyes were divided into two groups: standard conventional myopic LASIK (SM) (n = 101) and wavefront-guided myopic LASIK (WM) (n = 53). INTERVENTION: Retreatment LASIK was performed by lifting the original flap and using an excimer laser. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and complications were evaluated at a mean follow-up of 7.8+/-5.5 months after retreatment (range, 3-26). RESULTS: At the last visit, mean spherical equivalents (SEs) were -0.17+/-0.42 diopters (D) in the SM group and -0.11+/-0.34 D in the WM group (P = 0.394). An SE of +/-0.50 D was achieved in 87% (88/101) of SM eyes and 91% (49/53) of WM eyes. Seventy-five percent of eyes in both groups had UCVA> or =20/20. All eyes in the WM group and 98% of eyes in the SM group had 20/30 or better UCVA. All eyes in both groups had a postoperative BSCVA of 20/25 or better. No eyes lost 2 lines of BSCVA in either group. No sight-threatening complications were encountered. The number of eyes with pre-retreatment optical symptoms was reduced to half after retreatment. CONCLUSIONS: Our results suggest that retreatment with conventional LASIK is a safe, effective, predictable way of dealing with different types of residual refractive errors after both wavefront-guided and standard myopic LASIK.

Conventional and wavefront-guided myopic LASIK retreatment.

PURPOSE: To assess the clinical outcomes of conventional and wavefront-guided myopic laser in situ keratomileusis (LASIK) retreatment. DESIGN: Retrospective, nonrandomized case series. METHODS: The study comprised a cohort of 97 eyes having LASIK retreatment for residual myopia after primary LASIK. The eyes were divided into two groups: conventional retreatment (CR) group (n = 74) and wavefront-guided retreatment (WR) group (n = 23). The retreatment LASIK was performed using LADARVison 4000 with/without CustomCornea (Alcon Surgical, Orlando, Florida, USA). The mean follow-up was 8.9 +/- 5.8 months after retreatment (range three to thirty-six months). RESULTS: The mean pre-retreatment spherical equivalent (SE) was -0.93 +/- 0.41 diopters in the CR group and -0.84 +/- 0.48 diopters in the WR group (P = .409). At the last visit, the mean SE was -0.19 +/- 0.28 diopters and +0.32 +/- 0.47 diopters, respectively (P < .001). An SE of +/- 0.50 diopters was achieved in 92% (68 of 74) of CR eyes and 65% (15 of 23) of WR eyes. In the CR group, 85% eyes had a uncorrected visual acuity (UCVA) > or = 20/20 and 99% > or = 20/40, and in the WR group, 35% and 100%, respectively. None of the CR eyes and 17% (4 of 23) of WR eyes lost two lines of best spectacle-corrected visual acuity (BSCVA). Nine percent (7 of 74) of CR eyes and 30% of WR eyes (7 of 23) had optical symptoms before retreatment, the number was reduced to 1% (1 of 74) and 4% (1 of 23), respectively. CONCLUSIONS: In the study period with the current equipment, our results showed that conventional LASIK retreatment was superior to wavefront-guided LASIK retreatment in both efficacy and safety.

Laser in situ keratomileusis for primary and secondary mixed astigmatism.

PURPOSE: To evaluate and compare the efficacy, predictability, and safety of LASIK in the correction of primary and secondary mixed astigmatism after previous LASIK surgery. DESIGN: Retrospective, comparative case series. METHODS: The retrospective study included 118 eyes having LASIK with the LADARVison 4000 excimer laser (Alcon Surgical, Orlando, Florida) to correct mixed astigmatism. The eyes were divided into two groups: in group A (n = 64), LASIK was for primary mixed astigmatism and in group B (n = 54), LASIK was for secondary mixed astigmatism. Mean follow-up was 10.6 +/- 5.90 months. RESULTS: Overall, the postoperative UCVA was 20/20 in 51% of eyes and 20/40 or better in 97% of eyes at the last visit. The mean refractive cylinder was -2.18 +/- 0.94 D preoperatively and -0.56 +/- 0.56 D postoperatively. Sixty-one percent of eyes had a refractive cylinder of 0.50 D or less. One eye lost 2 lines of BSCVA (0.8%). None of the eyes had postoperative BSCVA worse than 20/25. The difference of preoperative cylinder was significant between group A and group B (P = .000). However, there was no statistical difference of postoperative refraction and UCVA between these two groups. At 12 months, the mean vector magnitude achieved was 93% of intended cylinder correction with a mean angle of error of -3.0 +/- 16 degrees. CONCLUSIONS: LASIK is a safe, effective, and predictable procedure to treat both primary and secondary mixed astigmatism. Nomogram adjustment with spherical and astigmatism components individually may improve refractive outcomes.