Changes in Accommodative and Binocular Function following Phakic Intraocular Lens for High and Low-to-Moderate Myopia.

The aim was to evaluate accommodative and binocular function of phakic intraocular lens implantable collamer lens (ICL) in high and low-to-moderate myopia. Prospective comparative cohort study with 38 myopic patients who underwent ICL implantation were divided into two groups of 19 patients, each one based on the spherical equivalent (SE): high-power (SE ≤ −6 D) and low-to-moderate (SE > −6 D). The push-up amplitude of accommodation (AA), monocular accommodative facility (MAF), distance and near ocular deviation, near convergence amplitude, near point convergence (NPC), stereopsis, and accommodative convergence/accommodation (AC/A) ratio were assessed before surgery and 1 week and 1 month postoperatively. The mean residual refractive error at 1 month after surgery improved in both groups, 0.18 ± 0.34 D and 0.09 ± 0.26 D, respectively (p < 0.001). There was a significant decrease in AA in both groups between preoperatively and at 1-week (p = 0.001; p = 0.008, respectively) and 1-month follow-up (p = 0.001; p = 0.008). For the rest of the binocular measurements, no statistically significant postoperative changes were found in any group. This finding suggests follow-up studies on amplitude of accommodation in phakic intraocular lens ICL implantation.

Interocular biometric parameters comparison measured with swept-source technology.

PURPOSE: In the event that any ocular parameter involved in the calculation of intraocular lens power could not be properly measured in one eye, it is important to know whether clinically relevant differences between both eyes can be expected. The aim of this work is to evaluate the symmetry of interocular biometric parameters. METHODS: This was a prospective, cross-sectional study involving 4090 subjects. Patients underwent consecutive swept-source optical biometry performed with an IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany). The biometric parameters that were evaluated were: axial length (AL), mean anterior curvature (Rm), anterior chamber depth (ACD), crystalline lens thickness (LT), central corneal thickness (CCT) and white-to-white (WTW). The Chang-Waring chord distance (CWC-D) and the Chang-Waring chord angle (CWC-A) were also evaluated. RESULTS: There is an excellent correlation between both eyes for almost all the biometric parameters under study, with the exception of the CWC. Agreement for AL was better for eyes shorter than 24 mm. The linearity of the OD-vs-OS relationship can be correctly assumed for all parameters (Cusum test: p > 0.05 in all cases). CONCLUSION: There are no clinically significant interocular differences for the biometric parameters under study, although for all of them, except the LT, statistically significant differences did arise. In the case of AL, moderate differences can be expected in eyes larger than 24 mm.

Feasibility of optical quality analysis system for the objective assessment of accommodation insufficiency: a phase 1 study.

PURPOSE: To assess differences in a new objective metric obtained with a double-pass technique between a group with accommodation insufficiency (AI) and a control group and to explore the diagnostic capabilities of this new tool in comparison to conventional procedures. METHODS: Retrospective cross-sectional case-control phase 1 study. Two groups with ages ranging from 8 to 18 years were recruited: AI and control group. The diagnostic criterion of AI was based on monocular accommodative amplitude (AA), 2 D below Hofstetter's calculation for minimum AA, and monocular accommodative facility (MAF), failing with minus lens and cut-off at ≤ 6 cycles per minute. Accommodative response with a double pass device (HD Analyzer, Visiometrics) was measured, performing an evaluation from +1.00 D to -3.50D (-0.5D steps), offering the width of the profile at 50% (WP) in minutes of arc. RESULTS: Differences were found between groups for the AA, MAF and MEM retinoscopy (p < 0.0001, p < 0.001, p = 0.037). The discriminative capacity of MEM retinoscopy for AI diagnosis was significant and the cut-off that maximized the sensitivity and specificity was > 0.5 D. Considering WP 50% in different points, the discriminative AI diagnosis capacities for the points of 2.0 D and 2.50 D were significant (ROC-AUC 0.78; p = 0.03 and p = 0.02). CONCLUSIONS: Double-pass system metric differed between patients with AI and control group, therefore the aim of a Phase I study was achieved. Further steps with higher sample sizes are required to evidence if the system really provides any advantage versus conventional methods in the diagnosis of AI.

Influence of angle κ on visual and refractive outcomes after implantation of a diffractive trifocal intraocular lens.

PURPOSE: To evaluate changes in angle κ after the implantation of a trifocal intraocular lens (IOL) and to assess the postoperative outcomes of patients with different angle κ values. SETTING: IOA Madrid Innova Ocular, Madrid, Spain. DESIGN: Prospective trial. METHODS: Sixty-three eyes from 63 patients who had bilateral implantation of a diffractive trifocal IOL (POD F, PhysIOL) were included. Pupil offset was used as the best estimate of angle κ and was measured using Pentacam (Oculus) preoperatively and at 3 months postoperatively. Postoperative refractive outcomes (sphere, cylinder, and manifest refraction spherical equivalent) and visual outcomes at far, intermediate, and near distance were assessed and compared between eyes with small pupil offset and eyes with large pupil offset. Quality of vision was assessed using a subjective questionnaire. RESULTS: There was a significant decrease in pupil offset values postoperatively (mean: 0.197 ± 0.12 mm) compared with those preoperatively (mean: 0.239 ± 0.12 mm), with a mean decrease of -0.042 mm (P = .0002). The same significant decrease was found for both right and left eyes, when analyzed separately. No statistically significant difference was found in any of the refractive and visual acuity outcomes between eyes with small pupil offset and eyes with large pupil offset. The majority of patients (14 of 16) complaining of significant halos had eyes with small pupil offset. CONCLUSIONS: Large pupil offset did not negatively affect visual and refractive outcomes. The tolerance to larger pupil offset might be due to the IOL optical design, with the first diffractive ring being larger than other commonly used multifocal IOLs. More studies comparing various diffractive IOL models would be useful to confirm such hypothesis.

The influence of surgeons and technicians on the learning curve of femtosecond-laser cataract surgery.

PURPOSE: To demonstrate the influence of the surgeon's and the operating room (OR) technicians' experience upon the outcome of femtosecond laser-assisted cataract surgery (FLACS). MATERIALS AND METHODS: Our study included 250 eyes from 156 patients who had undergone either cataract surgery or clear-crystalline-lens extraction and where capsulorhexis and lens fragmentation had been performed using the CATALYS® Precision System femtosecond platform (Abbott Medical Optics Inc., Santa Ana, CA, USA).The patients were operated either by an experienced surgeon in the use of femtosecond laser or by an inexperienced surgeon in that field and two technicians. The quantitative outcome measures were: Suction loss rate, vacuum time, number of consumables used by the patient and intraoperative complication rate. RESULTS: Both for the experienced and the inexperienced surgeons, suction loss rates as well as vacuum time decreased progressively as time went by and more surgical procedures had been completed by that surgeon. For a given surgeon suction time decreased significantly, going from 137 to 99s, as the assisting technician gradually gained experience. The number of consumables used in each procedure by the experienced surgeon ranged from 1.10 (for the first 50 cases) to 1.02 from those initial cases onwards. Regarding intraoperative complications, they also decreased progressively as the number of procedures completed by the surgeon increased. CONCLUSIONS: The experience of each team member involved in such procedures-be it surgeons or technicians-have an impact, to a greater or lesser extent, upon the surgery's outcome, as quantified by the outcome variables of choice.

Influence of trifocal intraocular lenses on standard autorefraction and aberrometer-based autorefraction.

PURPOSE: To study the agreement between manifest refraction and objective refraction measured with two autorefractor models and an aberrometer in eyes implanted with a trifocal diffractive intraocular lens (IOL). SETTING: IOA Madrid Innova Ocular, Madrid, Spain. DESIGN: Prospective comparative cohort study. METHODS: An autorefractor keratometer (KR-8800), based on a Scheiner double pinhole, and a 3-dimension wavefront topography aberrometer system (OPD-Scan III), based on the scanning-slit retinoscopy principle, were used to obtain objective refraction readings. In addition, lower-order Zernike coefficients (Z) were used to calculate objective refraction. A set of 7 different results was obtained in power vector notation (spherical equivalent [SE], Jackson cross-cylinder, axes at 180 degrees and 90 degrees [J0] and Jackson cross-cylinder, axes at 45 degrees and 135 degrees [J45]) for 7 different methods: manifest refraction, autorefraction obtained with the autorefractor keratometer, WF-P (Z-based objective refraction for the photopic pupil), WF-M (Z-based objective refraction for the mesopic pupil), WF-4 (Z-based objective refraction for a 4.0 mm pupil), OPD-C (autorefraction measured with the 3-dimension wavefront topography aberrometer system under photopic conditions), and OPD-M (autorefraction measured with the 3-dimension wavefront topography aberrometer system under mesopic conditions). RESULTS: The study comprised 102 eyes from 51 cataract patients who underwent binocular implantation of a diffractive trifocal IOL (FineVision POD F). All 6 objective methods yielded more negative SE values than manifest refraction (P < .001). As for the astigmatism components (J0 and J45), only autorefraction (P = .003) and OPD-M (P < .001) differed significantly from manifest refraction. The best and worst correlation for the SE component were intraclass correlation coefficient (ICC) = 0.70 (for WF-M) and ICC = 0.48 (for WF-4). CONCLUSION: Objective methods tend to yield more negative sphere values than manifest refraction.

Binocular vision alterations after refractive and cataract surgery: a review.

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.