Effects of short-term exposure to red or near-infrared light on axial length in young human subjects.

PURPOSE: To determine whether visible light is needed to elicit axial eye shortening by exposure to long wavelength light. METHODS: Incoherent narrow-band red (620 ± 10 nm) or near-infrared (NIR, 875 ± 30 nm) light was generated by an array of light-emitting diodes (LEDs) and projected monocularly in 17 myopic and 13 non-myopic subjects for 10 min. The fellow eye was occluded. Light sources were positioned 50 cm from the eye in a dark room. Axial length (AL) was measured before and after the exposure using low-coherence interferometry. RESULTS: Non-myopic subjects responded to red light with significant eye shortening, while NIR light induced minor axial elongation (-13.3 ± 17.3 µm vs. +6.5 ± 11.6 µm, respectively, p = 0.005). Only 41% of the myopic subjects responded to red light exposure with a decrease in AL and changes were therefore, on average, not significantly different from those observed with NIR light (+0.2 ± 12.1 µm vs. +1.1 ± 11.2 µm, respectively, p = 0.83). Interestingly, there was a significant correlation between refractive error and induced changes in AL after exposure to NIR light in myopic eyes (r(15) = -0.52, p = 0.03) and induced changes in AL after exposure to red light in non-myopic eyes (r(11) = 0.62, p = 0.02), with more induced axial elongation with increasing refractive error. CONCLUSIONS: Incoherent narrow-band red light at 620 nm induced axial shortening in 77% of non-myopic and 41% of myopic eyes. NIR light did not induce any significant changes in AL in either refractive group, suggesting that the beneficial effect of red laser light therapy on myopia progression requires visible stimulation and not simply thermal energy.

A retrospective study of cumulative absolute reduction in axial length after photobiomodulation therapy.

BACKGROUND: To assess the age and timeline distribution of ocular axial length shortening among myopic children treated with photobiomodulation therapy in the real world situations. METHODS: Retrospective study of photobiomodulation therapy in Chinese children aged 4 to 13 years old where axial length measurements were recorded and assessed to determine effectiveness at two age groups (4 ∼ 8 years old group and 9 ∼ 13 years old group). Data was collected from myopic children who received photobiomodulation therapy for 6 ∼ 12 months. Effectiveness of myopia control was defined as any follow-up axial length ≤ baseline axial length, confirming a reduction in axial length. Independent t-test was used to compare the effectiveness of the younger group and the older group with SPSS 22.0. RESULTS: 342 myopic children were included with mean age 8.64 ± 2.20 years and baseline mean axial length of 24.41 ± 1.17 mm. There were 85.40%, 46.30%, 71.20% and 58.30% children with axial length shortening recorded at follow-up for 1 month, 3 months, 6 months and 12 months, respectively. With respect to the axial length shortened eyes, the mean axial length difference (standard deviation) was - 0.039 (0.11) mm, -0.032 (0.11) mm, -0.037 (0.12) mm, -0.028 (0.57) mm at 1, 3, 6, and 12-month follow-up, respectively. Greater AL shortening was observed among the older group who had longer baseline axial lengths than the younger group (P < 0.001). CONCLUSIONS: Overall myopia control effectiveness using photobiomodulation therapy was shown to be age and time related, with the maximum absolute reduction in axial elongation being cumulative.

Efficacy of Repeated Low-Level Red Light (RLRL) therapy on myopia outcomes in children: a systematic review and meta-analysis.

BACKGROUND: Myopia is the most prevalent form of refractive error that has a major negative impact on visual function and causes blurring of vision. We aimed to determine if Repeated Low-Level Red Light (RLRL) treatment is beneficial in treating childhood myopia in terms of axial length (AL), spherical equivalent refraction (SER), and sub foveal choroidal thickness (SFCT). METHODS: This systematic review was performed on RLRL for treatment of myopia in children compared to single vision spectacles (SVS). We employed the search strategy with key terms myopia and low-level light therapy then we searched PubMed, Scopus, Cochrane, and Web of Science databases. The mean differences (MD) were used to evaluate the treatment effects. Heterogeneity was quantified using I2 statistics and explored by sensitivity analysis. RESULTS: Five randomized controlled trials (RCTs) were included in our meta-analysis with a total of 833 patients, 407 in treatment group and 426 in control group. At a 3 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.16; 95% CI [-0.19, -0.12], SER (MD = 0.33; 95% CI [0.27, 0.38]), and SFCT (MD = 43.65; 95% CI [23.72, 45.58]). At a 6 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.21; 95% CI [-0.28, -0.15]), SER (MD = 0.46; 95% CI [0.26, 0.65]), and SFCT (MD = 25.07; 95% CI [18.18, 31.95]). At a 12 month follow up period, pooled studies show a statistical difference in AL between RLRL and SVS group (MD = -0.31; 95% CI [-0.42, -0.19]) and SER (MD = 0.63; 95% CI [0.52, 0.73]). CONCLUSION: This is the first systematic review and meta-analysis investigating only RCTs evidence supporting the efficacy of 650 nm RLRL for myopia control in the short term of 3, 6, and 12 months follow up. The present review revealed the clinical significance of RLRL as a new alternative treatment for myopia control with good user acceptability and no documented functional or structural damage. However, the effect of long-term RLRL treatment and the rebound effect after cessation require further investigations.

Assessing the rebound phenomenon in different myopia control treatments: A systematic review.

PURPOSE: To review the rebound effect after cessation of different myopia control treatments. METHODS: A systematic review that included full-length randomised controlled studies (RCTs), as well as post-hoc analyses of RCTs reporting new findings on myopia control treatments rebound effect in two databases, PubMed and Web of Science, was performed according to the PRISMA statement. The search period was between 15 June 2023 and 30 June 2023. The Cochrane risk of bias tool was used to analyse the quality of the selected studies. RESULTS: A total of 11 studies were included in this systematic review. Unifying the rebound effects of all myopia control treatments, the mean rebound effect for axial length (AL) and spherical equivalent refraction (SER) were 0.10 ± 0.07 mm [-0.02 to 0.22] and -0.27 ± 0.2 D [-0.71 to -0.03] after 10.2 ± 7.4 months of washout, respectively. In addition, spectacles with highly aspherical lenslets or defocus incorporated multiple segments technology, soft multifocal contact lenses and orthokeratology showed lower rebound effects compared with atropine and low-level light therapy, with a mean rebound effect for AL and SER of 0.04 ± 0.04 mm [0 to 0.08] and -0.13 ± 0.07 D [-0.05 to -0.2], respectively. CONCLUSIONS: It appears that the different treatments for myopia control produce a rebound effect after their cessation. Specifically, optical treatments seem to produce less rebound effect than pharmacological or light therapies. However, more studies are required to confirm these results.

Short Wavelength (Blue) Light Is Protective for Lens-Induced Myopia in Guinea Pigs Potentially Through a Retinoic Acid-Related Mechanism.

Purpose: To investigate the effect of short-wavelength light (SL) on guinea pigs with lens-induced myopia (LIM) and the possible retinoic acid (RA)-related mechanisms. Methods: Two-week-old guinea pigs (n = 60) with monocular -5D lenses were reared under white light (WL, 580 lux) or SL (440 nm, 500 lux). The left eyes were uncovered as control. Refractive error (RE) and axial length (AL) were measured at baseline, one week, two weeks, and four weeks after intervention. Retinal RA was measured from four guinea pigs after two and four weeks of treatment with HPLC. Two-week-old guinea pigs (n = 52) with monocular -5D lens were fed with either RA or its synthesis inhibitor citral every third day in the morning, and half from each group were reared under WL or SL conditions. RE and AL were recorded at baseline and two and four weeks after intervention. Retinal RA was measured after four weeks of intervention. Results: At the end of treatment, guinea pigs exposed to SL were less myopic than to WL (2.06 ± 1.69D vs. -1.00 ± 1.88D), accompanied with shorter AL (P = 0.01) and less retinal RA (P = 0.02). SL reduced retinal RA even after exogenous RA supplementation (P = 0.02) and decelerated LIM compared to WL (1.66 ± 1.03D vs. -3.53 ± 0.90D). Citral slowed ocular growth, leading to similar RE in W+CI and S+CI groups (3.39 ± 1.65D vs. 5.25 ± 0.80D). Conclusions: Overall, SL reduced LIM in guinea pigs, even in those supplemented with oral RA, accompanied by reduced retinal RA levels. Oral RA accelerated eye elongation, but citral equally decelerated eye elongation under SL and WL with no significant retinal RA reduction.

Eye Rubbing and Transient Corneal Ectasia Detected by Topography in a Pediatric Patient.

ABSTRACT: We report on a 13-year-old girl undergoing changes in the refraction of her OS associated with eye rubbing. Corneal topography showed a corneal deformation in OS, classified as stage 1 keratoconus according to the Krumeich classification. A significant reduction in eye rubbing led to a normal corneal shape at the 1-year follow-up. Transient and fully reversible corneal ectasia can be caused by eye rubbing in pediatric age. This may have implications when counseling very young patients with eye rubbing.

Highlights from the 2019 International Myopia Summit on 'controversies in myopia'.

Myopia is an emerging public health issue with potentially significant economic and social impact, especially in East Asia. However, many uncertainties about myopia and its clinical management remain. The International Myopia Summit workgroup was convened by the Singapore Eye Research Institute, the WHO Regional Office for the Western Pacific and the International Agency for the Prevention of Blindness in 2019. The aim of this workgroup was to summarise available evidence, identify gaps or unmet needs and provide consensus on future directions for clinical research in myopia. In this review, among the many 'controversies in myopia' discussed, we highlight three main areas of consensus. First, development of interventions for the prevention of axial elongation and pathologic myopia is needed, which may require a multifaceted approach targeting the Bruch's membrane, choroid and/or sclera. Second, clinical myopia management requires co-operation between optometrists and ophthalmologists to provide patients with holistic care and a tailored approach that balances risks and benefits of treatment by using optical and pharmacological interventions. Third, current diagnostic technologies to detect myopic complications may be improved through collaboration between clinicians, researchers and industry. There is an unmet need to develop new imaging modalities for both structural and functional analyses and to establish normative databases for myopic eyes. In conclusion, the workgroup's call to action advocated for a paradigm shift towards a collaborative approach in the holistic clinical management of myopia.

Short-Wavelength (Violet) Light Protects Mice From Myopia Through Cone Signaling.

Purpose: Exposure to short-wavelength light influences refractive development and inhibits myopic development in many animal models. Retinal mechanisms underlying this response remain unknown. This study used a mouse model of lens-induced myopia to evaluate the effect of different wavelength light on refractive development and dopamine levels in the retina. A possible retinal pathway is tested using a mutant mouse with dysfunctional cones. Methods: Wild-type C57BL/6J (WT) and ALS/LtJ/Gnat2cpfl3 (Gnat2-/-) mice were exposed to one of three different light conditions beginning at postnatal day 28: broad-spectrum "white" (420-680 nm), medium wavelength "green" (525 ± 40 nm), and short wavelength "violet" (400 ± 20 nm). One-half of the mice received hyperopic lens defocus. All mice were exposed to the light for 4 weeks; animals were measured weekly for refractive error and axial parameters. Retinal dopamine and the dopamine metabolite 3,4-dihydroxyphenylacetic acid were measured by HPLC. Results: In WT mice, short-wavelength violet light induced hyperopia and violet light inhibited lens-induced myopia when compared with mice exposed to white light. Hyperopia could be attributed to shallower vitreous chambers in WT animals. There were no changes in the levels of dopamine or its metabolite. In Gnat2-/- mice, violet light did not induce hyperopia or inhibit lens-induced myopia. Conclusions: These findings show that short-wavelength light slows refractive eye growth, producing hyperopic responses in mice and inhibiting lens-induced myopia. The lack of inhibition in mice with dysfunctional cones suggests that cone signaling plays a role in the hyperopic response to short-wavelength (violet) light.

Photorefractive intrastromal corneal crosslinking for treatment of low myopia: clinical outcomes using the transepithelial approach with supplemental oxygen.

PURPOSE: To evaluate the safety and efficacy of photorefractive intrastromal corneal crosslinking (PiXL) for the treatment of low myopia using the epithelium-on approach with supplemental oxygen. SETTING: The Eye Foundation, Coimbatore, India. DESIGN: Prospective interventional case series. METHODS: Myopic nonectatic eyes underwent PiXL using the Mosaic system. Ultraviolet-A (UV-A) irradiation of 365 nm wavelength was delivered in an accelerated (30 mW/cm) pulsed approach to provide a total fluence of 15 J/cm. Supplemental oxygen (concentration greater than 95%) was provided to increase the efficacy of the epithelium-on approach during the UV-A irradiation. Efficacy was determined by improvement in mean refractive spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), and keratometric flattening. Safety was determined by loss of lines of corrected distance visual acuity, endothelial cell loss, and adverse events. RESULTS: Fifty eyes of 26 patients with a mean age of 22.73 ± 3.74 years were included. A significant improvement in UDVA from baseline (logarithm of the minimum angle of resolution [logMAR] 0.63 ± 0.25) was noted at the 3-month (logMAR 0.08 ± 0.15) and 6-month (logMAR 0.13 ± 0.18) follow-up visits (P < .001). Significant keratometric flattening from baseline was noted at all follow-up visits (P < .001). No significant endothelial cell loss or adverse effects were noted. A significant correlation was noted between the change in MRSE and preoperative corneal biomechanics (deformation amplitude ratio, P = .029). CONCLUSIONS: Transepithelial PiXL with supplemental oxygen might be a safe and effective approach for reduction of myopia. The change in MRSE and keratometric flattening was greater in comparison with earlier protocols, including the epithelium-off approach.

Femtosecond Laser-Assisted Penetrating Keratoplasty for Treating Infective Keratitis.

PURPOSE: To report the results of penetrating keratoplasty (PKP) assisted by femtosecond laser in the treatment of persistent infective keratitis. METHODS: Seven eyes of 7 patients with diagnosed infective keratitis were recruited. They showed no improvement on maximal medical therapy for a week. The causative organisms were Pseudomonas aeruginosa in 3 cases and Fusarium in 4 cases. All cases underwent femtosecond laser-assisted PKP with a mushroom-shaped cut. Postoperative antimicrobial medications were continued for 8-12 weeks. Sutures were removed after 6 months. Therapeutic success was defined as eradication of primary infection. Functional success was considered when visual function improves to 20/200 or better. RESULTS: All 7 eyes underwent femtosecond laser-assisted PKP. There were no intraoperative complications, and all patients had uneventful recipient cornea separation. Anatomic, therapeutic, and functional success was achieved in all patients. During the 6-month follow-up period, no recurrence of infection was reported. The average preoperative corrected distance visual acuity (CDVA) was 2.07 log of the minimal angle of resolution (LogMAR) ± 0.21, whereas at 6 months postoperatively, the average CDVA was 0.17 LogMAR ± 0.13, with a P value of 0.00025. CONCLUSIONS: Femtosecond laser-assisted PKP was found to be an effective method for treating infective keratitis (particularly that caused by Pseudomonas aeruginosa and Fusarium) that did not respond to medical treatment. Early surgical intervention before the disease becomes advanced is recommended.

Transepithelial photorefractive intrastromal corneal crosslinking versus photorefractive keratectomy in low myopia.

PURPOSE: To compare the outcomes of transepithelial photorefractive intrastromal corneal crosslinking (CXL) and photorefractive keratectomy (PRK) in eyes with low myopia. SETTING: Purpan Hospital, Toulouse, France. DESIGN: Prospective case series. METHODS: Myopic patients with a manifest refraction spherical equivalent (MRSE) of -1.00 to -2.50 diopters (D) and a cylindrical component of plano to -0.75 D were included. The dominant eye had PRK (PRK eyes). The nondominant eye had transepithelial photorefractive intrastromal CXL with riboflavin (ParaCel Part 1 and 2), 30 mW/cm2 pulsed ultraviolet-A irradiation centered on the pupil (Mosaic System) for 16 minutes and 40 seconds, and a supplemental oxygen delivery mask (CXL eyes). The primary outcome measure was the change in the MRSE. Other outcome measures were the uncorrected (UDVA) and corrected (CDVA) distance visual acuities, mean keratometry, and endothelial cell count (ECC) over a 6-month follow-up. Adverse events were assessed. RESULTS: Nineteen patients were included. By 6 months, the mean MRSE had decreased by 0.72 D ± 0.42 (SD) in CXL eyes and by 1.35 ± 0.46 D in PRK eyes (P < .001). The mean change in UDVA was -0.35 ± 0.21 logarithm of the minimum angle of resolution (logMAR) in CXL eyes and -0.66 ± 0.19 logMAR in PRK eyes (P < .001). No complications were reported. The change in the ECC and CDVA was not statistically significant. CONCLUSIONS: Photorefractive keratectomy provided better visual and refractive outcomes than transepithelial photorefractive intrastromal CXL. Transepithelial photorefractive intrastromal CXL, however, showed the potential refractive effect of CXL but with a limited magnitude of myopic correction.

Myopic shift and lens turbidity following hyperbaric oxygen therapy - a prospective, longitudinal, observational cohort study.

PURPOSE: To examine visual acuity, refraction and ocular status before, during and after hyperbaric oxygen therapy (HBOT). METHODS: Twenty-nine patients underwent 40 standard protocol HBOT treatments. In all subjects, refraction and best corrected visual acuity were measured at baseline and after ten, 20, 30 and 40 treatments, and at a 12-week follow-up. A subgroup (n = 19) were given additional examinations at baseline, after 40 treatments and at follow-up including measuring central corneal thickness (CCT), corneal curvature, anterior chamber depth, lens thickness, axial length, fundus morphology, blood pressure and intraocular pressure (IOP). Lens colour and opalescence were graded using the Lens Opacities Classification System III (LOCS III). RESULTS: Myopic shifts [≥0.5 dioptre (D) spherical equivalent (SE)] occurred in 45 (77.6%) eyes. Median refractive changes of -0.75 D SE (right eye; p < 0.001) and -0.66 D SE (left eye; p < 0.001) were observed between pretreatment and treatment end (Wilcoxon signed rank test). Refraction returned to baseline at follow-up, except for a small persisting change towards myopia, median -0.25 D SE (left eye; p = 0.01). Using the LOCS III, median increases in lens nuclear colour, of 0.6 (right eye; p < 0.001) and 0.7 (left eye; p < 0.001), and opalescence of 0.7 (both eyes; p = 0.01) were found at the last examination. Small reductions were noted in CCT of -6.00 µm (right eye; p = 0.03) and -4.00 µm (left eye; p = 0.03), and IOP of -1.50 mmHg (left eye; p = 0.01). CONCLUSIONS: The transient myopic shift may have been due to lenticular refractive index changes. Reduced lens transparency is a potential consequence of HBOT.

Outcomes for Hyperopic LASIK With the MEL 90® Excimer Laser.

PURPOSE: To report the outcomes of laser in situ keratomileusis (LASIK) for hyperopia using the Triple-A ablation profile with the MEL 90 excimer laser (Carl Zeiss Meditec, Jena, Germany). METHODS: This retrospective analysis included 1,383 eyes treated by LASIK for hyperopia using the Triple-A ablation profile with the MEL 90 at London Vision Clinic, London, United Kingdom, between September 2013 and December 2016. Inclusion criteria were attempted hyperopic correction of +0.25 diopters (D) or higher and corrected distance visual acuity (CDVA) of 20/40 or better. Patients were observed for 1 year after surgery. Standard outcomes analysis was performed. RESULTS: One-year data were available for 1,350 (97%) eyes. Mean attempted spherical equivalent refraction (SEQ) was +2.77 ± 1.34 D (range: +0.13 to +6.50 D) and mean cylinder was -0.67 ± 0.66 D (range: 0.00 to -5.00 D). Mean age was 54 ± 11 years (range: 21 to 75 years), and 57% were female. Postoperative spherical equivalent was ±0.50 D in 73% and ±1.00 D in 93% of eyes. Uncorrected distance visual acuity was 20/20 or better in 75% of eyes, relative to 93% with preoperative CDVA of 20/20 or better. One line of CDVA was lost in 17% of eyes and two lines were lost in 0.6% of eyes. There was a clinically insignificant but statistically significant increase (P < .01) in contrast sensitivity at 3 and 6 cycles per degree (cpd) and no change for 12 and 18 cpd. CONCLUSIONS: LASIK for hyperopia with the MEL 90 excimer laser was found to satisfy accepted criteria for safety, efficacy, and stability. [J Refract Surg. 2018;34(12):799-808.].

Outcomes for Mixed Cylinder LASIK With the MEL 90® Excimer Laser.

PURPOSE: To report the outcomes of LASIK for mixed cylinder using the Triple-A ablation profile with the MEL 90 excimer laser (Carl Zeiss Meditec, Jena, Germany). METHODS: This was a retrospective analysis of all eyes treated by LASIK for mixed cylinder using the Triple-A ablation profile with the MEL 90 laser between July 2013 and October 2016. Patients were observed for 1 year after surgery. Standard outcomes analysis and vector analysis by the Alpins method were performed. RESULTS: The database review identified 105 eyes (82 patients) treated by LASIK for mixed cylinder using the MEL 90 laser. Mean age was 40 ± 11 years (range: 18 to 65 years). Mean attempted spherical equivalent was +0.30 ± 0.90 diopters (D) (range: -2.30 to +1.75 D). Mean cylinder was -2.93 ± 1.47 D (range: -0.75 to -7.00 D). Preoperative corrected distance visual acuity (CDVA) was 20/20 or better in 81% of eyes. Postoperative uncorrected distance visual acuity was 20/20 or better in 69% and 20/25 or better in 86% of eyes. Mean postoperative spherical equivalent relative to the intended target was -0.21 ± 0.38 D (range: -1.25 to +1.13 D), with 83% within ±0.50 D. Mean postoperative cylinder was -0.57 ± 0.41 D (range: 0.00 to -1.75 D). Geometric mean was 1.12 for the correction index and 0.25 for the index of success. For angle of error, the arithmetic mean was -0.6° ± 4.2° (range: -13.5° to 9.5°) and the absolute mean was 2.9° ± 3.0° (range: 0.0° to 13.5°). There was loss of one line of CDVA in 3% of eyes and no eyes lost two or more lines CDVA. There was a small increase in contrast sensitivity after surgery at 3, 6, 12, and 18 cycles per degree (P < .05). CONCLUSIONS: One-year outcomes of LASIK using the MEL 90 laser for mixed cylinder up to -7.00 D demonstrated excellent efficacy, safety, and predictability. Vector analysis found a 12% overcorrection in magnitude of refractive cylinder. Given the high accuracy for angle of error, a nomogram could be applied to reduce the over-correction and further improve the uncorrected distance visual acuity outcomes. [J Refract Surg. 2018;34(10):672-680.].

Face-to-face upright seated positioning for cataract surgery in patients unable to lie flat: Case series of 240 consecutive phacoemulsifications.

PURPOSE: To present a case series of patients who were unable to lie flat for cataract surgery. SETTING: University teaching hospital, district hospital, and private practice, Norwich, United Kingdom. DESIGN: Prospective case series. METHODS: All patients had phacoemulsification using face-to-face upright seated positioning. The patient sits upright or semi-recumbent, and the surgeon sits or stands, facing the patient. The microscope is rotated forward, and surgery is done via an incision in the lower half of the cornea, using topical intracameral anesthesia. All 240 face-to-face cases, performed by the same surgeon, were prospectively recorded. The database included reasons for positioning difficulty, position adopted, and per-operative complications. Data on full systemic monitoring of 34 patients and satisfaction data on 90 patients were also recorded. RESULTS: In 13 years, 240 eyes (179 patients) had face-to-face surgery. Common diagnoses were severe kyphosis, orthopnea, or both. No patient was refused face-to-face surgery since the service was started. The rate of vitreous loss was 12 (5%) of 240 cases. However, all patients (100%) received a posterior chamber intraocular lens. No patient had any systemic adverse event, and vital signs remained stable during surgery. All respondents stated that they would be happy to have face-to-face positioning again. CONCLUSIONS: Face-to-face positioning, in the hands of an experienced surgeon, was an acceptably safe approach for patients unable to lie flat for cataract surgery. It might be the only option for some patients. However, all patients should be counseled regarding the increased risk for operative complications.

Femtosecond laser-assisted cataract surgery in pediatric patients.

Pediatric cataract surgery poses a significant challenge for the cataract surgeon, in part because an elastic anterior capsule can make capsulorhexis difficult. With the use of femtosecond laser-assisted cataract surgery (FLACS), however, the continuous curvilinear capsulorhexis can be made with predictable size, circular shape, centration, and accuracy. In addition, topical anesthesia can be used for the FLACS docking procedure in cooperative children above 6 years of age, using transparent adhesive polyurethane film segments.

Ciliary Muscle Electrostimulation to Restore Accommodation in Patients With Early Presbyopia: Preliminary Results.

PURPOSE: To report short-term results of pulsed ciliary muscle electrostimulation to improve near vision, likely through restoring accommodation in patients with emmetropic presbyopia. METHODS: In a prospective non-randomized trial, 27 patients from 40 to 51 years old were treated and 13 age- and refraction-matched individuals served as untreated controls. All patients had emmetropia and needed near sphere add between +0.75 and +1.50 diopters. The protocol included four sessions (one every 2 weeks within a 2-month period) of bilateral pulsed (2 sec on; 6 sec off) micro-electrostimulation with 26 mA for 8 minutes, using a commercially available medical device. The uncorrected distance visual acuity (UDVA) (logMAR) for each eye, uncorrected near (40 cm) visual acuity in each eye (UNVA) and with both eyes (UNVA OU) (logMAR), and reading speed (number of words read per minute at 40 cm) were measured preoperatively and 2 weeks after each session. Overall satisfaction (0 to 4 scale) was assessed 2 weeks after the last session. RESULTS: UDVA did not change and no adverse events were noted in either group. Bilateral and monocular UNVA and reading speed were stable in the control group, whereas they continuously improved in the treated group (Friedman, P < .00001). Post-hoc significant differences were found for monocular and binocular UNVA after the second treatment and after the first treatment considering words read per minute (P < .001). One patient (3.7%) was not satisfied and 18 patients (66.7%) were very satisfied (score of 4). Average satisfaction score was 3 (satisfied). CONCLUSIONS: Ciliary muscle contraction to restore accommodation was safe and improved the short-term accommodative ability of patients with early emmetropic presbyopia. [J Refract Surg. 2017;33(9):578-583.].

Effectiveness of an Eyelid Thermal Pulsation Procedure to Treat Recalcitrant Dry Eye Symptoms After Laser Vision Correction.

PURPOSE: To provide an initial retrospective evaluation of the effectiveness of a thermal pulsation system to treat intractable patient-reported dye eye symptoms following laser vision correction. METHODS: A total of 109 eyes of 57 patients underwent thermal pulsation therapy (LipiFlow; TearScience, Morrisville, NC) for the treatment of dry eye symptoms following laser vision correction. A standardized dry eye questionnaire, the Standard Patient Evaluation of Eye Dryness (SPEED II), was administered to all patients before and after thermal pulsation therapy. The primary outcome was patient-reported dry eye symptoms as measured by this questionnaire. RESULTS: The mean patient age was 49 years (interquartile range [IQR]: 38 to 60), 70% were female, and the primary refractive procedure was LASIK (n = 91, 83%) or photorefractive keratectomy (PRK) (n = 18, 17%). Patients underwent thermal pulsation therapy at a mean of 40.5 months (IQR: 27.6 to 55.0) after the primary procedure. The mean pre-therapy SPEED II questionnaire score was 17.5 (IQR: 14 to 21), with a reduced mean post-therapy score of 10.2 (IQR: 6 to 14; 95% confidence interval [CI]: 8.8 to 11.5, P < .001). Patients with PRK tended to report more improvement. At the follow-up clinical evaluation, objective improvements were noted in tear break-up time (+1.9 sec; 95% CI: 1.3 to 2.5), reduction in grade of meibomian gland dysfunction (-0.69; 95% CI: -0.54 to -0.84), and corneal staining (-0.74; 95% CI: -0.57 to -0.91). CONCLUSIONS: In this initial retrospective evaluation, a significant improvement in patient-reported dry eye symptoms was observed following thermal pulsation therapy. This treatment modality may have utility in the management of dry eye symptoms following laser vision correction, but further study is needed to define its role. [J Refract Surg. 2017;33(1):30-36.].

Protein Disulfide Levels and Lens Elasticity Modulation: Applications for Presbyopia.

PURPOSE: The purpose of the experiments described here was to determine the effects of lipoic acid (LA)-dependent disulfide reduction on mouse lens elasticity, to synthesize the choline ester of LA (LACE), and to characterize the effects of topical ocular doses of LACE on mouse lens elasticity. METHODS: Eight-month-old mouse lenses (C57BL/6J) were incubated for 12 hours in medium supplemented with selected levels (0-500 µM) of LA. Lens elasticity was measured using the coverslip method. After the elasticity measurements, P-SH and PSSP levels were determined in homogenates by differential alkylation before and after alkylation. Choline ester of LA was synthesized and characterized by mass spectrometry and HPLC. Eight-month-old C57BL/6J mice were treated with 2.5 µL of a formulation of 5% LACE three times per day at 8-hour intervals in the right eye (OD) for 5 weeks. After the final treatment, lenses were removed and placed in a cuvette containing buffer. Elasticity was determined with a computer-controlled instrument that provided Z-stage upward movements in 1-µm increments with concomitant force measurements with a Harvard Apparatus F10 isometric force transducer. The elasticity of lenses from 8-week-old C57BL/6J mice was determined for comparison. RESULTS: Lipoic acid treatment led to a concentration-dependent decrease in lens protein disulfides concurrent with an increase in lens elasticity. The structure and purity of newly synthesized LACE was confirmed. Aqueous humor concentrations of LA were higher in eyes of mice following topical ocular treatment with LACE than in mice following topical ocular treatment with LA. The lenses of the treated eyes of the old mice were more elastic than the lenses of untreated eyes (i.e., the relative force required for similar Z displacements was higher in the lenses of untreated eyes). In most instances, the lenses of the treated eyes were even more elastic than the lenses of the 8-week-old mice. CONCLUSIONS: As the elasticity of the human lens decreases with age, humans lose the ability to accommodate. The results, briefly described in this abstract, suggest a topical ocular treatment to increase lens elasticity through reduction of disulfides to restore accommodative amplitude.