To evaluate visual acuity, refractive outcomes, and anterior corneal higher-order aberrations (HOAs) after myopic laser in situ keratomileusis (LASIK) with uneventful single femtosecond laser pass ...versus double pass performed for intraoperative suction loss.
Private refractive surgery center, Valencia, Spain.
Cohort study.
After the LASIK flap was created with a single pass of an Intralase femtosecond laser in 1 eye and a double pass in the fellow eye, the ablation was performed with a Visx S2 laser. At 12 months, the refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, and anterior corneal HOAs were measured with 4.0 mm and 6.0 mm pupils.
The study enrolled 42 eyes (21 patients). Twelve months postoperatively, there were no statistically significant differences in any parameter studied including residual spherical equivalent (mean -0.05 diopter D ± 0.25 SD single pass; -0.03 ± 0.19 D double pass; P=.75), UDVA (mean 0.008 ± 0.057 logMAR single pass; 0.011 ± 0.046 logMAR double pass; P=.89), CDVA (mean -0.010 ± 0.040 logMAR single pass; -0.007 ± 0.037 logMAR double pass; P=.74), or anterior corneal HOAs. No eye lost 1 line of CDVA.
Visual acuity, refractive outcomes, and anterior corneal HOAs were comparable between eyes after uneventful femtosecond laser single pass or double pass after suction loss affecting the pupillary area. A new femtosecond laser pass performed immediately after incomplete flap due to intraoperative suction loss provided good visual and optical outcomes.
To evaluate the efficacy, predictability, safety, stability, and complications of the Artiflex toric iris-fixated phakic intraocular lens (pIOL) for myopic astigmatism.
Private practice surgery ...centers, Valencia and Terrassa, Spain.
Cohort study.
At 12 months, refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, complications, pIOL misalignment, and endothelial cell count (ECC) were evaluated. Indices of success and misalignment were calculated using vector analysis.
The study enrolled 42 eyes in 25 patients aged 21 to 39 years. The mean spherical equivalent decreased from -8.85 diopters (D) ± 2.71 (SD) to -0.37 ± 0.46 D, with 66.7% of the eyes within ± 0.50 D. The mean cylinder power decreased from -2.90 D (range -1.50 to -5.00 D) to -0.39 D (range 0.00 to -1.50 D); refraction was highly stable. All eyes achieved a decimal UDVA of 0.5 or better and a CDVA of 0.8 or better. A gain of 1 line or more of CDVA was found in 69.1% of eyes. The mean clinical pIOL misalignment was 2.6 ± 1.8 degrees; 1 eye (2.4%) required surgical repositioning of the pIOL. The mean ECC decrease was 9.3% ± 1.8%; iris pigment precipitates were observed in 16.7% of eyes. Vector analysis showed excellent mean indices of success for overall (0.94 ± 0.04), spherical (0.96 ± 0.05), and astigmatic (0.95 ± 0.16) corrections; the mean angle of error was 1.8 ± 2.7 degrees.
Implantation of the toric pIOL was effective, predictable, safe, and stable for the correction of myopic astigmatism.
No author has a financial or proprietary interest in any material or method mentioned.
To review binocular and accommodative disorders documented after corneal or intraocular refractive surgery, in normal healthy prepresbyopic patients. A bibliographic revision was performed; it ...included works published before 1st July 2017 where accommodation and/or binocularity was assessed following any type of refractive surgical procedure. The search in Pubmed yielded 1273 papers, 95 of which fulfilled the inclusion criteria. Few publications reporting binocular vision and/or accommodative changes after refractive surgery in normal subjects were found. The reduction in fusional vergence is the most frequently reported alteration. Anisometropia is an important risk factor for postoperative binocular vision‐related complaints. Most diplopia‐related visual complaints, irrespective of the surgical procedure, were in fact misdiagnosed preoperative disorders. The preoperative evaluation of patients seeking spectacle/contact lens independence should include a complete binocular and accommodation assessment where parameters such as the phoric posture, accommodative amplitude and facility, near point of convergence, fusional reserves and accommodative convergence/accommodation coefficient are measured. This would allow the identification of risk factors that could compromise the success of the refractive surgery and cause clinical symptoms.
To compare visual, refractive, and clinical outcomes of foldable iris-fixated phakic intraocular lens (PIOL) implantation versus femtosecond laser-assisted LASIK for myopia between -6.00 and -9.00 ...diopters (D).
Forty-six myopic patients were randomized to undergo bilateral Artiflex (Ophtec BV) PIOL implantation or bilateral femtosecond laser-assisted conventional LASIK with the VISX S2 (Abbott Medical Optics). Refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity, contrast sensitivity, corneal endothelial cell count, rate of retreatment, and complications were compared.
Twelve months after surgery, no statistically significant differences were noted in spherical equivalent refraction (P=.19) or UDVA (P=.28), whereas CDVA was better in the PIOL group (P<.001). Spherical equivalent refraction was within ±0.50 D in 42 (91.3%) LASIK eyes and 41 (89.1%) PIOL eyes (P>.99). The percentage of eyes gaining lines of CDVA was significantly higher in the PIOL group (50.0% vs 8.7%; P<.001). Contrast sensitivity was better for PIOL eyes at 1.5 cycles per degree (cpd) (P=.03) and 6 cpd (P=.008). The LASIK eyes showed a mean endothelial cell count increase of 3.7%±2.8%, whereas PIOL eyes showed a mean decrease of 9.1%±2.0% (P<.001). The rate of retreatment was similar (P=.37), and no serious complications occurred in either group.
The Artiflex PIOL provided better CDVA and contrast sensitivity at high spatial frequencies than femtosecond laser-assisted conventional LASIK, suggesting that PIOL implantation is a reasonable option for myopia between -6.00 and -9.00 D.
To compare contrast sensitivity and color vision in patients in whom blue-light filtering and non-yellow-tinted intraocular lenses (IOLs) were implanted.
Refractive Surgery Unit, Hospital NISA ...Valencia al Mar, Valencia, Spain.
Forty eyes of 20 patients were enrolled in a blue-light filtering fellow-eye control study; patients were implanted with a yellow-tinted IOL (AcrySof Natural, Alcon) in 1 eye and a non-yellow-tinted IOL (AcrySof SA60AT, Alcon) in the fellow eye after cataract surgery. Three months postoperatively, monocular contrast sensitivity function was measured with the CSV 1000-E contrast sensitivity chart at distance and the color discrimination with the Farnsworth-Munsell 100 Hue test.
Eyes implanted with blue-light filtering IOLs showed similar contrast sensitivity to that in fellow eyes implanted with non-yellow-tinted IOLs (P>.1). Both types of IOLs showed normal contrast sensitivity values (normalized log-contrast sensitivity about 1.0). There were no statistically significant differences in chromatic discrimination between the 2 types of IOLs (P = .56).
The use of blue-light filtering IOLs is more advisable because they are capable of protecting the retina against ultraviolet light without disturbance of contrast sensitivity and chromatic vision, which produces subjective impairment in visual function.
To evaluate the visual performance of an aberration-free intraocular lens (IOL) in patients with different corneal profiles using adaptive optics visual simulation.
A crx1 adaptive optics visual ...simulator was used to simulate the aberration pattern of an aberration-free IOL combined with five corneal profiles: virgin corneas and corneas with low and high myopic ablations and low and high hyperopic ablations. Ten eyes of 10 subjects were evaluated, and monocular distance visual acuity (VA) at 100%, 50% and 10% of contrast was measured.
At 100% of contrast, no differences were found in VA values among virgin corneas, low and high myopic ablations and low hyperopic ablation groups (p=0.06). All these groups achieved better results than the high hyperopic ablation group (p<0.001). At 50% and 10%, the best values of VA were obtained for the virgin corneas and for the low myopic and low hyperopic ablation groups (p>0.1, for both levels of contrast). Significant differences were found between these three corneal profiles and the other two corneal profiles (p<0.002 for high myopic and p<0.001 for high hyperopic, for both levels of contrasts).
The results suggest that the aberration-free IOL design gives an excellent visual performance for a range of corneal spherical aberrations that could correspond to patients with virgin corneas and patients in which the corneal spherical aberration has been slightly modified by a hyperopic or myopic laser ablation.
To assess the effects of LASIK with the 15-kHz IntraLase femtosecond laser on corneal endothelium.
In a prospective, single-center clinical trial, 138 patients (mean age: 32.0 ± 7.1 years range: 21 ...to 42 years) underwent femtosecond LASIK for the correction of myopia -0.75 to -9.00 diopters (D) and cylinder up to 3.25 D. Patients were divided into two groups: contact lens group (n=76) and non-contact lens group (n=62). Pre- and 12-month postoperative specular microscopy of the central corneal endothelium was performed. The integrity of the central endothelium was assessed in terms of endothelial cell density and percentage of hexagonality.
In the contact lens group, mean endothelial cell density improved significantly from 3401 ± 292 cells/mm(2) to 3587 ± 262 cells/mm(2) (P<.001) with a mean increase of 5.5%. The percentage of hexagonal cells was statistically significantly higher after surgery (32.5 ± 4.0%) compared with preoperative data (31.0 ± 5.1%) (P=.035). No statistically significant differences were noted regarding mean endothelial cell density (P=.126) or hexagonality (P=.56) before and 1 year after femtosecond LASIK in the non-contact lens group.
Femtosecond LASIK to correct myopia was safe for the corneal endothelium. Improvement in mean endothelial cell density and percentage of hexagonality was observed in the contact lens group.
To assess the differences in visual performance between orthokeratology (ortho-k) and laser in situ keratomileusis (LASIK) for the treatment of low-to-moderate myopia.
An adaptive optics visual ...simulator (Imagine Eyes) was used to simulate the wavefront aberration patterns induced by ortho-k and LASIK for low and moderate myopia on 10 healthy eyes. Visual acuity (VA) at 100%, 50%, and 10% contrast levels and contrast sensitivity (CS) at 10, 20 and 25 cycles per degree (cpd) were then measured for 3- and 6-mm pupil sizes.
Differences in VA for 3-mm pupil diameter were not found between ortho-k and LASIK. For 6-mm pupil size, LASIK provided significantly better VA values than ortho-k at 50% and 10% contrast levels for low myopia correction (P = 0.002 and P = 0.001, respectively) and at all contrast levels for moderate myopia correction (P = 0.04 at 100%, P < 0.0001 for 50% and 10% contrast levels). For 3-mm pupil size, differences in CS were not significant between both techniques for low myopia correction and were only significant at 25 cpd (P = 0.03) for moderate myopia correction. For 6-mm pupil diameter, LASIK provided better CS than ortho-k for 20 and 25 cpd for low myopia (P = 0.02 and P = 0.01, respectively) and at all spatial frequencies for moderate myopia (P = 0.02 for 10 cpd and P < 0.0001 for 20 and 25 cpd).
The results in this study suggest that LASIK provides better visual quality outcomes than ortho-k for the treatment of low-to-moderate myopia.
The aim was to evaluate the visual performance provided with a contact lens-based pinhole design against a simultaneous vision multifocal contact lens.
In a cross-over study at the University of ...Valencia, 22 presbyopic patients were evaluated using an artificial pupil fitted on the non-dominant eye and the simultaneous vision PureVision Multifocal contact lenses. After one month of contact lens wear, binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance contrast sensitivity, binocular near contrast sensitivity, and stereoacuity were measured, under photopic conditions (85-cd/m
2
). In addition, binocular distance visual acuity and binocular distance contrast sensitivity were examined under mesopic conditions (5-cd/m
2
).
Mean binocular distance visual acuity for pinhole and PureVision Multifocal were 0.02 ± 0.04 and 0.01 ± 0.04 logMAR under photopic conditions and 0.16 ± 0.06 and 0.12 ± 0.04 logMAR for binocular near visual acuity under mesopic conditions, respectively. No statistically significant differences were found between both types of lenses at distance for both lighting levels and intermediate distances (p > 0.05). There was a significant difference at near vision under photopic conditions (p = 0.03). Binocular distance contrast sensitivity revealed statistically significant differences between the pinhole system and PureVision Multifocal for six and 12-cpd (cycles per degree) spatial frequencies at the two luminance levels, while for near vision, differences were also significant for 18-cpd. Stereoacuity was better with PureVision Multifocal (127 ± 49.3 seconds of arc) compared with the pinhole lens (220.2 ± 32.3 seconds of arc, p = 0.004).
Pinhole and PureVision Multifocal contact lenses provide good binocular vision for distance and functional intermediate vision. Although it was better with the PureVision Multifocal, near vision was not satisfactory for either of the two contact lens options.
Purpose
To quantify the optical quality of various daily disposable contact lenses in vivo and to ascertain its variation in terms of wearing time by means of objective non‐invasive determination of ...wavefront patterns.
Methods
The crx1 adaptive‐optics system was used to measure the wavefront aberrations in 15 myopic eyes before and at 2‐h intervals after contact lens fitting, over a 12‐h wearing period. Seven types of contact lenses having different material, water content and lens design were evaluated in this study: Dailies Total1, Dailies AquaComfort Plus, Proclear 1 Day, 1‐Day Acuvue TruEye, 1‐Day Acuvue moist, SofLens daily disposable and Clariti 1‐Day. The aberration data were analysed by fitting Zernike polynomials up to the 5th‐order for 3 and 5‐mm pupils. The optical quality under each condition and at each point in time was described by means of the Root‐Mean‐Square (RMS) value of wavefront aberration, Modulation Transfer Function (MTF), Point Spread Function and cut‐off spatial frequency.
Results
A RMS increase was observed after contact lens fitting as well as over time, both for a 3‐mm and a 5‐mm pupil. Each type of lens induced a different amount of wavefront aberrations, which vary over time also in a different manner. Dailies Total1 showed the lowest RMS values both at baseline and at the end of the day. In addition, Dailies Total1 provided the best MTF out of all the contact lenses that were assessed. These observations were reflected in higher cut‐off spatial frequencies and visual resolution both at baseline and after 12 h of wearing time.
Conclusions
Aberrometry makes it possible to analyse accurately and in vivo the optical quality of contact lenses and to assess how lenses having different characteristics – such as material or water content – behave for different wearing times. These variations across contact lenses may result in differences in visual performance.
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