A randomized controlled trial comparing femtosecond-enabled deep anterior lamellar keratoplasty and standard deep anterior lamellar keratoplasty (FEDS Study).

OBJECTIVES: To compare outcomes of femtosecond-enabled deep anterior lamellar keratoplasty (FE-DALK) and standard deep anterior lamellar keratoplasty (S-DALK). METHODS: An open label, randomized controlled trial (Kensington Eye Institute, Toronto, ON, Canada) including 100 eyes of 97 participants with either keratoconus or corneal scarring, randomized to either FE-DALK (n = 48) or S-DALK (n = 49). PRIMARY OUTCOMES: postoperative astigmatism and surgically induced corneal astigmatism (SIA) - both at 15 months. SECONDARY OUTCOMES: 6-, 12- and 15-month postoperative uncorrected- and best spectacle-corrected visual acuity, steep and flat keratometry, manifest sphere and astigmatism, rate of conversion to penetrating keratoplasty (PK), big-bubble success, central corneal thickness, endothelial cell count and complications. RESULTS: In intention-to-treat analysis, mean postoperative astigmatism in the FE-DALK (n = 30) and S-DALK (n = 30) groups at 15 months was 7.8 ± 4.4 D and 6.3 ± 5.0 D, respectively (p = 0.282) with an adjusted mean difference of 1.3 D (95% CI -1.08, +3.65). Mean SIA (arithmetic) was 9.2 ± 7.8 and 8.8 ± 5.4 D, respectively (p = 0.838) with a mean difference of 0.4 D (95% CI -3.13, +3.85). In an analysis of successful DALK cases only, mean postoperative astigmatism in the FE-DALK (n = 24) and S-DALK (n = 20) groups at 15 months (after excluding 4 eyes with AEs) was 7.3 ± 4.4 and 6.2 ± 4.9 D, respectively (p = 0.531) with an adjusted mean difference of 0.9 D (95% CI -1.94, +3.71). Mean SIA (arithmetic) was 9.1 ± 7.8 and 7.9 ± 4.6 D, respectively (p = 0.547) with a mean difference of 1.2 D (95% CI -2.70,+5.02). Comparison of secondary outcomes showed only weak statistical evidence. CONCLUSIONS: In this randomized controlled trial, FE-DALK and S-DALK showed comparable functional and anatomical outcomes.

Accelerated Corneal Cross-Linking: Efficacy, Risk of Progression, and Characteristics Affecting Outcomes. A Large, Single-Center Prospective Study.

PURPOSE: We examined the efficacy and preoperative characteristics that affect outcomes of accelerated (9 mW/cm2 for 10 minutes) corneal cross-linking (CXL). DESIGN: Prospective single-center observational cohort study. METHODS: We enrolled 612 eyes of 391 subjects with progressive keratoconus (n = 589), pellucid marginal degeneration (n = 11), and laser in situ keratomileusis-induced ectasia (n = 12). We evaluated best spectacle-corrected visual acuity (BSCVA), topography, refraction, endothelial cell density, corneal thickness, haze, intraocular pressure, and visual function before and 12 months after the CXL procedure. We tabulated the proportion of those with progression of maximum keratometry (Kmax). We included participant's race, age, sex, and the presence of preoperative apical scarring and environmental allergies in a multivariable linear regression model to determine the effect of these characteristics on outcomes. RESULTS: At 1 year there was no significant change in mean Kmax (n = 569). Progression of Kmax was higher in subgroups with a baseline Kmax >58 diopters (n = 191) and those 14-18 years of age (n = 53). Preoperative BSCVA, Kmax, refraction, corneal cylinder, coma, central corneal thickness, and vision function were statistically and clinically significant predictors of outcomes (P < .001). Preoperative apical scarring led to worsening haze (P = .0001), more astigmatism (P = .002), more central corneal thinning (P = .002), and was protective to the endothelium (P = .008). Race, age, and sex affected some outcomes. CONCLUSION: Mean Kmax was stable at 1 year after accelerated CXL. Younger patients and those with a higher preoperative Kmax need to be monitored closely for progression. Preoperative BSCVA, topography, refraction, CCT, and apical scarring were significant predictors of outcomes.

Comparison of accelerated CXL alone, accelerated CXL-ICRS, and accelerated CXL-TG-PRK in progressive keratoconus and other corneal ectasias.

PURPOSE: To compare accelerated corneal crosslinking (CXL) alone, CXL with simultaneous intrastromal corneal ring segments (CXL-ICRS), and CXL with simultaneous topography-guided photorefractive keratectomy (CXL-TG-PRK) in progressive keratoconus, pellucid marginal degeneration (PMD), or laser in situ keratomileusis (LASIK)-induced ectasia. SETTING: The Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada. DESIGN: Prospective nonrandomized interventional study. METHODS: Visual and topographical outcomes using a comparative analysis adjusting for preoperative maximum keratometry (Kmax) were evaluated 1 year postoperatively. RESULTS: Four hundred fifty-two eyes from 375 patients with progressive keratoconus, PMD, or LASIK-induced ectasia that underwent accelerated (9 mW/cm, 10 minutes) CXL alone (n = 204), CXL-ICRS (n = 126), or CXL-TG-PRK (n = 122) were included. Change in logarithm of the minimum angle of resolution uncorrected distance visual acuity was significant with CXL-ICRS (-0.31; 95% CI, -0.38 to -0.24) and CXL-TG-PRK (-0.16; 95% CI, -0.24 to -0.09), but not with CXL alone. No significant differences in change were found between the 3 groups. Change in corrected distance visual acuity (CDVA) was significant in all 3 groups: -0.12 (95% CI, -0.15 to -0.10) with CXL alone, -0.23 (95% CI, -0.27 to -0.20) with CXL-ICRS, and -0.17 (95% CI, -0.21 to -0.13) with CXL-TG-PRK. Improvement in CDVA was greater with CXL-ICRS than with CXL alone (-0.08 ± 0.02; P < .0001) and CXL-TG-PRK (-0.05 ± 0.02; P = .005). Change in Kmax was significant with CXL-ICRS [-3.21 diopters (D); 95% CI, -3.98 to -2.45] and CXL-TG-PRK (-3.69 D; 95% CI, -4.49 to -2.90), but not with CXL alone (-0.05 D; 95% CI, -0.66 to 0.55). CONCLUSIONS: CXL alone might be best for keratoconic patients who meet the inclusion criteria. CXL-ICRS might be more effective for eyes with more irregular astigmatism and worse CDVA and CXL-TG-PRK for eyes requiring improvements in irregular astigmatism but still have good CDVA.

Light flashbacks during retinal laser photocoagulation following fluorescein angiography.

BACKGROUND AND OBJECTIVE: Yellow light flashbacks can often be seen in cases of laser photocoagulation performed shortly after fluorescein angiography. To determine whether unblocked secondary emission from retained aqueous and vitreous fluorescein may be reaching the treating ophthalmologist, the absorption characteristics of serial dilutions of sodium fluorescein were studied at wavelengths similar to the output of the krypton laser. MATERIALS AND METHODS: A Unicam sp500 series II visible spectrophotometer (Pye Unicam Ltd., Cambridge, UK) was used to measure fluorescein absorption at serial dilutions ranging from 100,000,000 to 100 ng/mL at 488, 518, 568, and 647 nm. sive dilution of fluorescein concentration and with increased wavelength. Blue (488 nm) and green (518 nm) light absorbed at all dilutions of fluorescein. Yellow light (568 nm) did not show any significant absorption below a concentration of 100,000 ng/mL and red light (647 nm) absorbed little below a concentration of 3,000,000 ng/mL. CONCLUSIONS: Dilutions of fluorescein absorbed all commonly used laser wavelengths. There is concern that fluorescein absorption results in emission of light at 520 nm (range: 450 to 700 nm), which may not be blocked by the filters currently placed in fixed laser delivery systems.

Design of a Subtarsal Ultrasonic Transducer for Mild Hyperthermia Treatment of Dry Eye Disease.

Dry eye disease is a disorder of the ocular surface that causes pain and low vision in a significant portion of the adult population. A common cause is obstructive Meibomian gland dysfunction, whereby the Meibomian glands secrete abnormal meibum with a melting point elevated by 3°C-4°C; hence, hyperthermia is the typical treatment. A design is proposed for an ultrasound hyperthermia device made of a transducer contained inside a contact lens with an internal air gap. The transducer heats the posterior of the tarsus, and the air gap provides an air backing to the transducer, preventing direct heating of the cornea. A prototype device was built, and hyperthermia experiments were performed on a porcine subject in vivo. A therapeutic temperature rise of 5°C-7°C was achievable in 10-15 min. The temperature of the cornea did not rise more than 2°C during any of the experiments.

Monovision correction for small-angle diplopia.

PURPOSE: To assess quantitatively the efficacy of monovision correction in the treatment of acquired small-angle binocular diplopia in adult patients. DESIGN: Prospective, interventional case series. METHODS: Twenty patients with symptomatic diplopia were enrolled in a prospective treatment trial at a tertiary university neuro-ophthalmology practice. All had stable deviations of 10 prism diopters or less for more than 3 months. Each received monovision spectacles, contact lenses, or both with distance correction in the dominant eye. Half received a +3.00-diopter add and the others received +2.50 diopters. The validated and standardized Diplopia Questionnaire and Amblyopia and Strabismus Questionnaire were used to quantify the efficacy of monovision correction for diplopia by measuring the functional impact on vision-specific quality of life. RESULTS: primary outcome: Based on the results of the Diplopia Questionnaire, 85% of patients experienced significant improvement in diplopia symptoms after monovision correction. There was a statistically significant 58.6% improvement in the Diplopia Questionnaire score in our patients (P < .0001). secondary outcome: The Amblyopia and Strabismus Questionnaire scores demonstrated improved quality of life and daily function after monovision correction (P = .03), especially in the areas of double vision(P = .0003) and social contact and appearance (P = .0002). CONCLUSIONS: Monovision decreased the frequency of diplopia and improved subjects' quality of life. Monovision may be a feasible alternative for presbyopic diplopic patients who are dissatisfied with other conservative treatment options.

Serial measurement of tear meniscus by FD-OCT after instillation of artificial tears in patients with dry eyes.

BACKGROUND AND OBJECTIVE: To use Fourier-domain optical coherence tomography (FD-OCT) to study the effect of artificial tears on the tear meniscus in patients with dry eyes. PATIENTS AND METHODS: The lower tear meniscus of 16 consecutive patients with dry eyes was imaged by an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA). Baseline and five serial pairs of measurements were taken after the instillation of artificial tears (Optive; Allergan, Irvine, CA) at 1, 2, 5, 10, and 15 minutes. The lower meniscus height, depth, and area were measured with a computer caliper. RESULTS: Baseline meniscus measurements were 235.5 ± 150.0 µm, 138.1 ± 78.7 µm, and 0.020 ± 0.022 mm(2) for height, depth, and area, respectively. After instillation of artificial tears, all lower tear meniscus parameters remained significantly elevated for 5 minutes and returned to baseline by 10 minutes. CONCLUSION: FD-OCT is able to quantify a dramatic initial increase in tear meniscus, followed by a decay back to baseline values after approximately 5 minutes. FD-OCT may be useful in objectively quantifying the dynamic efficacy of dry eye treatments.

Between-grader repeatability of tear meniscus measurements using Fourier-domain OCT in patients with dry eye.

BACKGROUND AND OBJECTIVE: To examine the between-grader repeatability of height, depth, and cross-sectional area measurements of the lower tear meniscus, using a Fourier-domain optical coherence tomography (OCT) system. PATIENTS AND METHODS: A total of 16 patients with dry eye had the lower tear meniscus of the right eye imaged twice in rapid succession. The tear meniscus height, depth, and cross-sectional area were measured by two masked graders using computer calipers. The between-grader variability, calculated using the pooled coefficient of variation (CV%), assessed the repeatability of the measurements. RESULTS: The between-grader CV% was 12.1%, 15.7%, and 19.5% for height, depth, and area, respectively. The between-image variability was 17.1%, 13.4%, and 35.4% for height, depth, and area, respectively. The overall intraclass correlation was 99%. There was no systematic bias between the two graders. CONCLUSION: Fourier-domain OCT demonstrates good between-grader and between-image repeatability in measuring the height, depth, and cross-sectional area of the tear meniscus in patients with dry eye. Measurement variability was primarily due to the difference between images rather than graders.