Characterization, passive and active treatment in strabismic amblyopia: a narrative review

Strabismic amblyopia is characterized by a distorted spatial perception.In this condition,the neurofunctional disorder occurring during first years of life provoke several monocular and binocular anomalies such as crowding,deficits in the accommodative response,contrast sensitivity,and ocular motility abilities.The inhibition of the binocular function of the brain by the misaligned amblyopic eye induces a binocular imbalance leading to interocular suppression and the reduction or lack of stereoacuity.Passive treatments such as occlusion,optical and/or pharmacological penalization,and Bangerter foils has been demonstrated to be potentially useful treatments for strabismic amblyopia.Recent researches have proved new pharmacological options to improve and maintain visual acuity af ter occlusion treatment in strabismic amblyopia.Likewise,the active vision therapy,in the last years,is becoming a very relevant therapeutic option in combination with passive treatments,especially during and after monocular therapy,in the attempt of recovering the imbalanced binocular vision.

Trifocal toric intraocular lenses in eyes with low amount of corneal astigmatism

AIM:To evaluate the refractive and visual outcomes following cataract surgery and implantation of a trifocal toric intraocular lens(IOL)in eyes with low degrees of corneal astigmatism.METHODS:Twenty-six eyes of 22 patients who underwent implantation a trifocal toric IOL(FineVision PODFT,PhysIOL s.a.,Liege,Belgium)were enrolled.Phacoemulsification with femtosecond laser,capsular tension ring insertion and intraoperative aberrometry were performed in all cases.All IOLs used showed a cylinder power of 1.00 D.Main outcome measures were refractive error and corrected-distance visual acuity(CDVA)and uncorrected-distance visual acuity(UDVA)values.Eyes were evaluated at 4 mo post-surgery.RESULTS:Totally 50%of eyes showed a spherical equivalent(SE)within±0.13 D and all of them within±0.50 D.The mean SE and refractive cylinder were-0.02±0.23 and-0.16±0.22 D,respectively.Vector analysis revealed that 100%of eyes were within±0.50 D for the SE and cylindrical components(J0 and J45).Refractive changes were not correlated with keratometric changes(P>0.05)showing that the reduction in astigmatism comes from the trifocal toric IOL.Of 81%and 96%of eyes showed UDVA and CDVA of 20/20,respectively.The postoperative mean values of monocular distance Snellen decimal UDVA and CDVA were 0.97±0.05 and 0.99±0.02(about 20/20),respectively.CONCLUSION:Our study suggests that the use of this trifocal toric IOL in patients with low amount of astigmatism provides accurate refractive outcomes and enables them to achieve excellent visual acuity.

Angle-to-angle and spur-to-spur distance analysis with high-resolution optical coherence tomography

Background:To measure angle-to-angle(ATA)and spur-to-spur(STS)distances along six meridians using highresolution swept-source optical coherence tomography(SS-OCT)and to compare those values with horizontal white-to-white(WTW)distance.Methods:Sixty-eight eyes from 68 patients were quantitatively assessed with the Anterion SS-OCT(Heidelberg Engineering,Heidelberg,Germany).ATA and STS distances were measured with the SS-OCT B-scan in six cross-sectional images corresponding to the vertical(6-12 o'clock),1-7 o'clock,2-8 o'clock,horizontal(3-9 o'clock),4-10 o'clock and 5-11 o'clock meridians.WTW was measured horizontally with the device's infrared camera.A Pearson correlation analysis was carried out to compare ATA and STS distances with WTW.Results:The largest values were found for the vertical meridian and the shortest for the 2-8 o'clock meridian,both for ATA and STS distances.No statistically significant differences were found between WTW,ATA and STS along the horizontal meridian(P>0.1).However,ATA and STS showed statistically significant differences elsewhere,except for the horizontal and the 2-8 o'clock meridians(P>0.05).Moreover,we found that ATA and STS varied significantly depending on the meridian being assessed,except for ATA at 4-10 versus 3-9 o'clock and for STS at 4-10 versus 3-9 o'clock and at 3-9 versus 2-8 o'clock(P>0.1).R2 values ranged from 0.49 to 0.75 for ATA and STS at the different meridians,showing the best correlation at 3-9 o'clock meridian(0.64 and 0.75,respectively)and the worst at 6-12 o'clock meridian(R2=0.49 for both ATA and STS).Conclusions:ATA and STS distances vary radially,thus showing that the anterior chamber is vertically oval.Therefore,it is advisable to measure these two distances along the meridian to be used.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

Background: The aim of this review is to summarize the optical quality results in patients following theimplantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc.).Main text: A literature search in several databases was carried out to identify those publications, both prospective,retrospective and/or comparative with other refractive surgery procedures, reporting optical outcomes of patientswho were implanted with the V4c ICL model. A total of 17 clinical studies published between 2012 and 2021 wereincluded in this review. A detailed analysis of the available data was performed including number of eyes, follow-upand preoperative spherical equivalent. Specifically, the review focused on several optical parameters includinghigher-order aberrations (HOAs), modulation transfer function (MTF) cut-off frequency and Strehl ratio. This reviewencompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack, retinal imagequality measurement and ray-tracing technologies at different follow-ups.Conclusions: The outcomes found in this review lead us to conclude that the ICL V4c model provides good opticalquality, by means of different metrics, when implanted.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

Background:The aim of this review is to summarize the optical quality results in patients following the implantation of the V4c implantable collamer lens with a central port(ICL,STAAR Surgical Inc.).Main text:A literature search in several databases was carried out to identify those publications,both prospective,retrospective and/or comparative with other refractive surgery procedures,reporting optical outcomes of patients who were implanted with the V4c ICL model.A total of 17 clinical studies published between 2012 and 2021 were included in this review.A detailed analysis of the available data was performed including number of eyes,follow-up and preoperative spherical equivalent.Specifically,the review focused on several optical parameters including higher-order aberrations(HOAs),modulation transfer function(MTF)cut-off frequency and Strehl ratio.This review encompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack,retinal image quality measurement and ray-tracing technologies at different follow-ups.Conclusions:The outcomes found in this review lead us to conclude that the ICL V4c model provides good optical quality,by means of different metrics,when implanted.

Angle-to-angle and spur-to-spur distance analysis with high-resolution optical coherence tomography

Background:To measure angle-to-angle(ATA)and spur-to-spur(STS)distances along six meridians using highresolution swept-source optical coherence tomography(SS-OCT)and to compare those values with horizontal white-to-white(WTW)distance.Methods:68 eyes from 68 patients were quantitatively assessed with the Anterion SS-OCT(Heidelberg Engineering,Heidelberg,Germany).ATA and STS distances were measured with the SS-OCT’s B-Scan in six cross-sectional images corresponding to the vertical(6-12 o’clock),1-7 o’clock,2-8 o’clock,horizontal(3-9 o’clock),4-10 o’clock and 5-11 o’clock meridians.WTW was measured horizontally with the device’s infrared camera.A Pearson correlation analysis was carried out to compare ATA and STS distances with WTW.Results:The largest values were found for the vertical meridian and the shortest for the 2-8 o’clock meridian,both for ATA and STS distances.No statistically significant differences were found between WTW,ATA and STS along the horizontal meridian(p>0.1).However,ATA and STS showed statistically significant differences elsewhere,except for the horizontal and the 2-8 o’clock meridians(p>0.05).Moreover,we found that ATA and STS varied significantly depending on the meridian being assessed,except for ATA at 4-10 versus 3-9 o’clock and for STS at 4-10 versus 3-9 o’clock and at 3-9 versus 2-8 o’clock(p>0.1).R^(2) values ranged from 0.49 to 0.75 for ATA and STS at the different meridians,showing the best correlation at 3-9 o’clock meridian(0.64 and 0.75,respectively)and the worst at 6-12 o’clock meridian(R^(2)=0.49 for both ATA and STS).Conclusions:ATA and STS distances vary radially,thus showing that the anterior chamber is vertically oval.Therefore,it is advisable to measure these two distances along the meridian to be used.