Determining and Comparing the Effective Lens Position and Refractive Outcome of a Novel Rhexis-Fixated Lens to Established Lens Designs

PURPOSE

WE sought to evaluate differences in effective lens position (ELP) based on the lens design. Intraocular lenses (IOLs) with plate-haptic, c-loop haptic, and a rhexis-fixated lens were compared.

DESIGN

Retrospective, multicenter, comparative case series.

METHODS

The study included patients having age-related cataract surgery with implantation of either a plate-haptic, c-loop haptic, or a novel rhexis-fixated IOL. Biometry and refraction measurements were conducted preoperatively and 3 months postoperatively. Lens constant optimization was performed.

RESULTS

Seventy eyes of 56 subjects were included. ELP for rhexis-fixated IOL was shortest (4.29 ± 0.24 mm), followed by c-loop haptic (4.41 ± 0.42 mm) and plate-haptic (4.51 ± 0.26 mm) IOL. Difference in ELP was significant between rhexis-fixated IOL and both plate-haptic (P = .001) and c-loop haptic IOL (P = .000). Anterior chamber depth adjustment based on lens design showed a significant effect on refraction and IOL power predictions for all formulas and lenses (P < .05). For the rhexis-fixated IOL the differences in refraction ranged from -0.039 diopters (D) for the Hill-Radial Basis Function to -0.096 D for Haigis. The other 2 lenses showed mean differences in refraction between +0.046 D for Hill-Radial Basis Function and +0.097 D for Haigis.

CONCLUSION

The difference in IOL fixation and its resulting position in the capsular bag have a significant effect on the effective lens position and consequently a significant effect on the prediction of postoperative refraction.

[Enhancements after Refractive Corneal Surgery]

This review article focusses on the management of enhancements after corneal refractive laser surgery. Fundamental issues regarding enhancement embrace identification of the underlying reason for postoperative ametropia, assurance of stability of refraction, type of primary refractive laser treatment and thorough evaluation of the given anatomical parameters of the cornea. With respect to specific inclusion and exclusion criteria, different surgical options for enhancement strategies are displayed with their particular advantages and disadvantages including preoperative planning of the according laser parameters and postoperative patient management.

Refraktive Hornhautchirurgie: Nachkorrekturen

In den 30 Jahren seit Beginn der laserassistierten Hornhautchirurgie sind die Techniken zur Korrektur von Fehlsichtigkeiten weiterentwickelt und verbessert worden. Dennoch muss ein Teil der Patienten nachkorrigiert werden, u. a. wegen residualer Refraktionsfehler. Darüber soll im Folgenden berichtet werden.

[Current state of knowledge on special lenses]

Patients undergoing lens surgery nowadays have the option to choose between different intraocular lens (IOL) options depending on the ocular situation and personal preferences. For example, it is possible to implant a toric IOL to compensate for extensive corneal distortion or a multifocal IOL to have good visual acuity at various distances. The high level of competition in the lens market leads to fast development of new lens models giving patients the advantage to choose between a variety of options. This review article presents the most commonly used premium IOL options namely, aspheric, toric and multifocal IOLs and a summary of the current study situation for the different lens types. Compared to standard lenses, these lenses can improve uncorrected distance and near visual acuity; however, in some patients the added benefit can be only marginal and this is then an unnecessary cost factor for the patient. Furthermore, if inclusion and exclusion criteria are not respected the special forms of lenses can even lead to a poorer overall result.

Comparing refractive outcomes of a standard industry toric IOL calculator using anterior corneal astigmatism and total corneal refractive power

PURPOSE

To evaluate refractive outcomes for a standard industry calculator using anterior corneal astigmatism or total corneal refractive power.

METHODS

This prospective interventional study evaluated the refractive outcomes of 56 eyes using a standard industry calculator (Zeiss ZCalc) and a digital IOL alignment software. After A-constant optimisation the ZCalc was recalculated with two different keratometry values using appropriate refractive indices: anterior corneal astigmatism (ACA) by IOLMaster 700 and total corneal refractive power (TCRP) by Pentacam. The Barrett toric calculator was used as a reference.

RESULTS

Undercorrection of 0.04 ± 0.42 D after 1 week and 0.13 ± 0.48 D after 3 months was achieved for the spherical equivalent by using a standard industry calculator. IOL misalignment was 2.8° ± 3.4° using a digital alignment system. For the ZCalc, the mean absolute error could be reduced from 0.19 ± 0.40 D using ACA to 0.04 ± 0.48 D when considering total corneal refractive power (p = 0.06). The Barrett calculator delivered better refractive outcomes than using a standard industry calculator with ACA measurements only (- 0.06 ± 0.43 D; p < 0.01).

CONCLUSION

Reliable and accurate refractive outcomes in toric IOL calculation were achieved by using the ZCalc calculator. The prediction error for a widely used standard industry toric IOL calculator could be reduced by using measured total corneal refractive power.

Comparison of 9 modern intraocular lens power calculation formulas for a quadrifocal intraocular lens

PURPOSE

To evaluate the accuracy of 9 formulas (Barrett Universal II, Haigis, Hill-Radial Basis Function [RBF], Hoffer Q, Holladay 1, Holladay 2, Olsen, Sanders-Retzlaff-Kraff/theoretical [SRK/T], and T2) calculating the power of the quadrifocal Acrysof IQ Panoptix TFNT00 intraocular lens (IOL).

SETTING

Department of Ophthalmology, Goethe University, Frankfurt, Germany.

DESIGN

Retrospective case series.

METHODS

The study included patients having cataract surgery with insertion of a quadrifocal IOL over 15 months. Preoperative biometry measurements were obtained from an IOLMaster 500. Optimized IOL constants were calculated to reduce the mean refractive prediction error. The primary outcomes were differences in mean absolute prediction error between the formulas. Median and maximum absolute prediction errors were evaluated as well as percentages of eyes within prediction errors of ±0.25 diopters (D), ±0.50 D, ±1.00 D, and ±2.00 D.

RESULTS

The study comprised 75 eyes of 38 patients. The formulas were ranked by the mean absolute refractive prediction error as follows: Barrett Universal II (0.294 D), Hill-RBF (0.332 D), Olsen (0.339 D), T2 (0.351 D), Holladay 1 (0.381 D), Haigis (0.382 D), SRK/T (0.393 D), Holladay 2 (0.399 D), and Hoffer Q (0.410 D). The differences in absolute errors between the formulas were significant (P < .001). The lowest maximum absolute prediction error was obtained with the Barrett Universal II.

CONCLUSION

The most accurate predictions of actual postoperative refraction were achieved using the Barrett Universal II, Hill-RBF, Olsen, or T2 formula. Thus, one of these formulas should be used for IOL power calculation of the quadrifocal IOL.

[Lens Surgery: Implantation of Multifocal Intraocular Lenses]

Lens exchange surgery is the most common performed surgical ophthalmological procedure worldwide. The intraocular lens (IOL) is placed into the capsular bag. The power of the IOL decides whether afterwards the patient will be able to see objects in the far or near distance without glasses. Due to constant development of the IOL design in nowadays it is however possible to implant a lens which has multiple foci and consequently allows the patient to see in several distances. In this review article we summarize the most critical points which need to be considered when placement of a multifocal lens is planned in lens exchange surgery. Additionally, we present an overview of the currently available trifocal IOLs and IOLs with an extended depth of focus. We furthermore discuss the advantages and disadvantages of the multifocal IOLs as compared to monofocal IOLs.

OCT angiography in optic disc drusen: comparison with structural and functional parameters

BACKGROUND

Optic disc drusen (ODD) can cause retinal nerve fibre layer (RNFL) defects with progressive visual field (VF) loss. Microvascular changes are discussed as a cause. We measured the vessel density (VD) of the optic disc in ODD using optical coherence tomography angiography and compared it with a normal population. Another intent was to determine the sensitivity and correlations in comparison with functional (VF) and structural parameters (RNFL, minimum rim width (MRW), ganglion cell complex (GCC)).

METHODS

We analysed the VD of 25 patients with ODD and an age-matched control population including 25 healthy participants using AngioVue (Optovue, Fremont, CA, USA). We obtained data about RNFL, GCC, Bruch's membrane opening MRW (Spectralis HRA & OCT; Heidelberg Engineering, Germany) and VF (standard automated perimetry; SITA 24-2). Low image quality and pathologies interfering with the diagnostics were excluded. Parametric data were analysed using the t-test and non-parametric values using the Mann-Whitney U test. Linear regression analysis was used to determine correlations using the Bravais-Pearson test.

RESULTS

The VD was significantly reduced in the ODD group especially the peripapillary capillary VD (n=45 vs 50 eyes; mean 43.15% vs 51.70%). Peripapillary RNFL thickness correlated with the VD significantly (r=0.902 (n=44), 0.901 (n=44), 0.866 (n=45)). The RNFL analysis showed a reduction in ODD, especially the superior hemisphere (mean 107 µm, 129 µm; 49 vs 50 eyes). The GCC was significantly lower in the ODD group (n=38 vs 40; mean 87 µm vs 98 µm). Positive correlation between the VD and the GCC was significant (n=37, r=0.532). There is a significant negative correlation (n=19; r=-0.726) between the VD and the pattern standard deviation (PSD).

CONCLUSION

This study reveals significant peripapillary microvascular changes in patients with ODD correlating with the RNFL and GCC reduction. There is a negative correlation between the PSD and the VD.

Linsenchirurgie: Einsatz von multifokalen Intraokularlinsen

Der Austausch der natürlichen Linse mittels einer künstlichen Intraokularlinse gehört zu den weltweit am häufigsten durchgeführten Operationen. In diesem Artikel werden die gängigsten multifokalen Linsen zusammengefasst und die wichtigsten Aspekte für den klinischen Alltag dargestellt.

Determinants of subjective patient-reported quality of vision after small-incision lenticule extraction

PURPOSE

To characterize patient-reported long-term quality of vision (QoV) after small-incision lenticule extraction (SMILE), and to identify potential clinical parameters that might predispose to experiencing deteriorated visual quality.

SETTING

University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany.

DESIGN

Prospective cross-sectional study.

METHODS

For the assessment and scoring of visual symptoms, the Quality of Vision questionnaire was employed, which constitutes a clinically validated, linear-scaled 30-item instrument providing a QoV score on three scales (symptom frequency, severity, and bothersome). Subgroup analyses were performed for patient subgroups stratified by baseline characteristics (eg, age) and treatment parameters (eg, surgical refractive correction) as well as refractive outcomes (eg, residual refraction) and visual outcomes (eg, uncorrected distance visual acuity [UDVA]).

RESULTS

The study comprised 394 eyes of 197 patients (117 women [59.4%], 80 men [40.6%]) were included with a mean postoperative follow-up of 24.4 months ± 14.1 (SD). The QoV scores for symptom frequency, severity, and bothersome were 34.63 ± 13.69, 29.60 ± 12.38, and 24.56 ± 16.00, respectively. Patients with a preoperative binocular corrected distance visual acuity (CDVA) of 20/12.5 or better, patients who lost 1 or more lines of UDVA as compared with preoperative CDVA, patients older than the age of 40, and patients with inadvertent anisometropia more than 0.375 diopters reported worse QoV scores.

CONCLUSION

The relationship between objective clinical parameters and patient-reported subjective QoV after SMILE seems complex. Defined prognostic factors that convey a higher risk for experiencing visual disturbances were identifiable and should be discussed with patients seeking SMILE treatment during preoperative counseling.

Outcome of Descemet membrane endothelial keratoplasty for graft failure after Descemet stripping automated endothelial keratoplasty

Purpose

To investigate the efficacy and safety of Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following primary Descemet stripping automated endothelial keratoplasty (DSAEK).

Methods

This was a retrospective case series of 15 patients that underwent DMEK surgery for corneal decompensation after failed DSAEK. Main outcome parameter was corrected distance visual acuity (CDVA) after DMEK and DSAEK. Secondary outcome measures included central corneal thickness (CCT), endothelial cell density (ECD), rebubbling rate, and primary graft failure after DMEK. Explanted DSAEK grafts were evaluated by light microscopy.

Results

The mean (±SD) time period between DSAEK and DMEK surgery was 15±8 months (range, 6–31 months). Preoperative CDVA was 1.72±0.62 (logMAR). After DMEK, CDVA improved significantly to 0.78±0.48 at 1 month and to 0.23±0.24 after 12 months (P=0.022). Visual acuity data after DMEK were significantly better compared to preoperative values. The average CCT after DMEK decreased significantly from 869±210 µm (preoperative) to 505±45 µm (1 month postoperative) (P<0.001) and remained stable over 12 months. The ECD decreased from 2,589±209/mm² (preoperative) to 1,691±589/mm² (12 months postoperative). Rebubbling DMEK was required in three patients (=20%).

Conclusion

DMEK represents a feasible and safe procedure in achieving better functional results compared to DSAEK. Visual acuity and optical quality can be effectively reestablished after unsuccessful primary DSAEK surgery even in patients with long-standing corneal decompensation. Further investigations are required to validate the preliminary clinical findings.

Functional outcome of repeat Descemet membrane endothelial keratoplasty (DMEK) for corneal decompensation following graft failure after primary DMEK

Purpose

To evaluate if repeat Descemet membrane endothelial keratoplasty (DMEK) is appropriate to achieve functional improvements in patients with corneal decompensation from secondary graft failure after primary DMEK.

Methods

This is a retrospective monocentric cohort study including 13 eyes of 13 patients with repeat DMEK for corneal decompensation following primary DMEK. Eyes with primary DMEK only and comparable preoperative corrected distance visual acuity (CDVA) served as control. Main outcome parameter was CDVA. Secondary outcome measures were central corneal thickness (CCT), endothelial cell density, and rebubbling rate (RR).

Results

The average time interval (±SD) between primary and secondary DMEK was 12.5±6 months. Preoperative CDVA (logMAR) was 1.97±0.90 in the repeat DMEK group and 1.38±0.92 in the primary DMEK group. At 6 months, both groups showed significant improvement in visual acuity (repeat DMEK group, 0.49±0.35, P<0.01 and primary DMEK group, 0.40±0.36, P<0.01). CDVA did not differ significantly between both groups at all time points examined (1, 3, and 6 months postoperatively). Mean CCT values at 3 and 6 months postoperatively did not differ significantly between the two groups (P>0.05). The RR was 23% (n=3) in both groups.

Conclusion

Repeat DMEK is a useful therapeutic approach in the setting of corneal decompensation following primary DMEK. Functional results of repeat DMEK, visual acuity in particular, are comparable to patients with single DMEK only.

Anterior Chamber Angle, Volume, and Depth in a Normative Cohort-A Retrospective Cross-Sectional Study

Purpose: The purpose of the study was to determine the distribution of the anterior chamber angle (ACA) within a population-based study sample in Germany and to find correlations between age, sphere, and biometric parameters of the anterior chamber. Patients and Methods: A total of 500 eyes, approximately 100 eyes per decade starting with patient age of 20 years, of 463 patients with an average age of 45.2 ± 14.1 (±values subsequent represent standard deviation) years without any known history of ocular diseases, surgery, or optic nerve head excavation or hypoplasia were included. ACAs, volume, and depth were correlated to age and sphere. Scheimpflug images (Pentacam, Oculus) with automatically measured ACAs were compared to manually measured angles (Bland Altman analysis) in this healthy population. Results: The mean manually measured ACA was 26.5° ± 3.9°; the highest average angle was found in the temporal position with 28.1° ± 4.9°, while the lowest average angle was found in nasal superior position with 25.7° ± 4.7°. Statistical analysis showed an average difference of +11.4° nasal and +12.1° temporal between the automatic measurements and the manually measured angles (P < 0.01). The analysis also revealed an independent inverted correlation between age (correlation coefficient between -0.28 and -0.38) and sphere (correlation coefficient between -0.44 and -0.51) of the participants and the anterior chamber volume, angle, and anterior chamber depth (P < 0.01 for all correlations). Conclusion: The ACA width manually measured is considerably less compared to automated imaging and formerly reported values. There is a significant difference in the ACA dependent on the position of measurement (superior, nasal, inferior, and temporal) with the average angle being inversely correlated to age and sphere. Abbreviations: AC: anterior chamber ACA: anterior chamber angle ACV: anterior chamber volume ACD: anterior chamber depth AAC: acute angle closure OAG: open-angle glaucoma OCT: optical coherence tomography ACG: angle-closure glaucoma MIGS: microinvasive glaucoma surgery PACS: primary angle-closure suspects.

Comparison of standard and accelerated corneal cross-linking for the treatment of keratoconus: a meta-analysis

PURPOSE

To compare results between standard and accelerated corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus.

METHODS

We performed literature searches in PubMed, Cochrane Library, Web of Science, ISRCTN registry, ClinicalTrials.gov, and EMBASE for studies comparing conventional Dresden (C-CXL) and accelerated CXL (A-CXL). Outcomes were clinical results and changes in corneal properties. Weighted mean differences were used to evaluate the effects.

RESULTS

Here, 22 studies with 1158 eyes (C-CXL: 577 eyes; A-CXL: 581 eyes) were included. At the last follow-up, C-CXL was superior regarding minimum keratometry (p < 0.00001) and demarcation line depth (p < 0.00001), whereas A-CXL should be favoured when considering minimum corneal thickness (p = 0.0005). No differences in uncorrected and corrected distance visual acuity (p = 0.09 and 0.98), spherical equivalent (p = 0.11), spherical and cylindrical error (p = 0.29 and 0.32), maximal and average keratometry (p = 0.05 and 0.65), central corneal thickness (p = 0.15), corneal biomechanical properties (p ≥ 0.21 respectively), time of reepithelialization (p = 0.76), subbasal nerve density (p = 0.69), endothelial cell density (p = 0.30) and morphology (p ≥ 0.40 respectively) were found among both groups.

CONCLUSION

Consideration of less corneal thinning favours A-CXL, whereas the deeper demarcation line and greater changes in minimum keratometric values in C-CXL may indicate a higher treatment efficacy. Altogether, C-CXL, as well as A-CXL, provides successful results in the strengthening of corneal tissue.

Impact of lens density and lens thickness on cumulative dissipated energy in femtosecond laser-assisted cataract surgery

To evaluate the required cumulative dissipated energy (CDE) to fragment the crystalline lens in femtosecond laser-assisted cataract surgery (FLACS) in relation to lens density and lens thickness. Consecutive eyes that underwent FLACS between September 2014 and March 2017 by a single surgeon using in all cases the same femtosecond laser and phacoemulsification platform were included in our retrospective study. Prior to surgery, corrected distance visual acuity (CDVA), optical biometry corneal, and crystalline lens tomographies were performed to assess anterior chamber depth (ACD), axial length (AL), and crystalline lens parameters (i.e., lens density, thickness, and nucleus staging (NS)). After surgery, CDE was calculated and analyzed in relation to lens density (LD) and lens thickness (LT). Zero ultrasound expenditure cases were recorded and their occurrence analyzed. The chart review identified 236 eyes of 200 patients, 98 males and 102 females aged 65± 15 years which were included in the study. Mean LD was 11.26 ± 2.05 pixel intensity units (range 7.30-18.80), and the mean LT was 3417 ± 405.17 μm (range 2545-4701). LD and LT correlated moderately (r = 0.50, p < 0.001) and weakly (r = 0.23, p < 0.001), with post-laser CDE. Higher LD and LT were also associated with lower rates of zero phaco (eyes in which no phacoemulsification energy was necessary). Furthermore, NS (r = 0.528, p < 0.001) and CDVA (r = - 0.3524, p < 0.001) also correlated with CDE. Higher LD, LT, NS values, and low CDVA are associated with higher ultrasound expenditure (CDE-cumulative dissipated energy) and with lower rates of zero ultrasound expenditure during FLACS.

Dependency of endothelial cell loss on anterior chamber depth within first 4 years after implantation of iris-supported phakic intraocular lenses to treat high myopia

PURPOSE

To evaluate the effect of the anterior chamber depth (ACD) on the central corneal endothelial cell density (ECD) in eyes after implantation of an iris-fixated phakic intraocular lens (pIOL).

SETTING

Department of Ophthalmology, Goethe-University, Frankfurt, Germany.

DESIGN

Retrospective nonrandomized case series.

METHODS

An Artisan pIOL was implanted in eyes of highly myopic patients. Follow-up examinations at 1, 12, 24, 36, and 48 months included evaluation of ECD and adverse events. Three cohorts based on the ACD were established and their ECDs compared. All eyes had 1-year and 4-year postoperative ECD measurements available. Statistical analysis included linear regression analysis to evaluate the influence of ACD on ECD.

RESULTS

The study comprised 95 eyes (52 patients). Four years after surgery the mean spherical equivalent changed from -11.06 diopters (D) ± 4.77 (SD) to -0.42 ± 0.47 D. Severe adverse events were not detected. There was a significantly higher ECD loss after 4 years in patients with an ACD of less than 3.00 mm than in those with an ACD greater than 3.40 mm (-224 cells/mm²) (P < .01). There was no significant difference in ECD between eyes with an ACD of 3.00 to 3.39 mm and eyes with an ACD less than 3.00 mm (P = .23) or more than 3.40 mm (P = .08).

CONCLUSIONS

The iris-claw pIOL precisely and safely corrected high myopia. However, the loss in ECD can be considerable. Establishing stricter exclusion criteria for ACD might reduce this loss.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Short-term complications of femtosecond laser-assisted laser in situ keratomileusis cuts: Review of 1210 consecutive cases

PURPOSE

To evaluate short-term complications after femtosecond laser cuts for laser in situ keratomileusis (LASIK).

SETTING

Department of Ophthalmology, Goethe University, Frankfurt, Germany.

DESIGN

Retrospective consecutive case series.

METHODS

Consecutive femtosecond laser cuts (1210 cuts in 624 patients) from LASIK performed with the Intralase FS60 between 2006 and 2014 were analyzed. The analysis looked at intraoperative and postoperative complications at 1 day, 1 week, and 1 month and factors with potential impact on the complication rate, such as ablation depth.

RESULTS

No irregular, incomplete, or thin flaps, buttonholes, gas breakthrough, or free caps were observed. Intraoperatively, incomplete side cuts were observed in 4 cases (0.3%). Three of the 4 occurred during the first year of femtosecond laser usage and were explained by a software problem. Epithelial defects, limbal bleeding, and decentered flaps without negative impact on outcome were observed in 45 (3.7%), 12 (1.0%), and 5 (0.4%) eyes, respectively, on the treatment date. Diffuse lamellar keratitis (DLK) stage 1 was observed in 69 (5.7%), 36 (3.0%), and 3 (0.2%) eyes at 1 day, 1 week, and 1 month, respectively, and DLK stage 2 in 20 (1.7%), 6 (0.5%), and 2 (0.2%) eyes, respectively. An increase in total ablation depth resulted in a higher incidence of microstriae (P < .01 at 1 day, 1 week, and 1 month). An increase in the optical zone resulted in a significantly higher incidence of epithelial ingrowth at 1 day and 1 week (P < .01).

CONCLUSION

No major cut-related complications were observed. The femtosecond laser is a safe option to create a flap in LASIK.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosures are listed after the references.

Impact of a Displaced Corneal Apex in Small Incision Lenticule Extraction

PURPOSE

To evaluate the possible impact of a displaced corneal apex (point of maximum curvature) on visual results and tomographic parameters after small incision lenticule extraction (SMILE).

METHODS

In this retrospective evaluation, eyes with uncomplicated SMILE for myopia correction were classified in two groups based on their preoperative distance between the corneal apex and corneal vertex (corneal intercept with the patient's line of sight) of 1 mm or greater (large A-V distance) or less than 1 mm (small A-V distance). All surgeries were performed during the early learning curve of two surgeons. Visual outcome parameters included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refractive spherical equivalent (MRSE), and refractive astigmatism 3 months postoperatively. Scheimpflug-derived tomographic outcome parameters included mean keratometry value, root mean square higher order aberrations (RMS HOAs), and optical zone decentration.

RESULTS

The study comprised 94 eyes of 48 patients: 44 eyes in the large A-V distance group and 50 eyes in the small A-V distance group. Preoperative and postoperative RMS HOAs were significantly higher in the large A-V distance group than in the small A-V distance group (P = .002 and .008, respectively). Postoperative CDVA was significantly better in the small A-V distance group (P = .014). There were no statistically significant differences in postoperative UDVA, MRSE, refractive astigmatism, mean keratometry value, and optical zone decentration.

CONCLUSIONS

After SMILE, CDVA was significantly worse in eyes with a preoperatively displaced corneal apex compared to eyes with a more central corneal apex. However, good visual results were achieved in both groups. [J Refract Surg. 2018;34(7):460-465.].

Evaluation of keratoconus progression

AIM

To define variables for the evaluation of keratoconus progression and to determine cut-off values.

METHODS

In this retrospective cohort study (2010-2016), 265 eyes of 165 patients diagnosed with keratoconus underwent two Scheimpflug measurements (Pentacam) that took place 1 year apart ±3 months. Variables used for keratoconus detection were evaluated for progression and a correlation analysis was performed. By logistic regression analysis, a keratoconus progression index (KPI) was defined. Receiver-operating characteristic curve (ROC) analysis was performed and Youden Index calculated to determine cut-off values.

RESULTS

Variables used for keratoconus detection showed a weak correlation with each other (eg, correlation r=0.245 between RPImin and Kmax, p<0.001). Therefore, we used parameters that took several variables into consideration (eg, D-index, index of surface variance, index for height asymmetry, KPI). KPI was defined by logistic regression and consisted of a Pachymin coefficient of -0.78 (p=0.001), a maximum elevation of back surface coefficient of 0.27 and coefficient of corneal curvature at the zone 3 mm away from the thinnest point on the posterior corneal surface of -12.44 (both p<0.001). The two variables with the highest Youden Index in the ROC analysis were D-index and KPI: D-index had a cut-off of 0.4175 (70.6% sensitivity) and Youden Index of 0.606. Cut-off for KPI was -0.78196 (84.7% sensitivity) and a Youden Index of 0.747; both 90% specificity.

CONCLUSIONS

Keratoconus progression should be defined by evaluating parameters that consider several corneal changes; we suggest D-index and KPI to detect progression.

Comparison of fibrotic response in the human lens capsular bag after femtosecond laser-assisted cataract surgery and conventional phacoemulsification

PURPOSE

To compare the effect of different laser pulse energy settings in femtosecond laser-assisted cataract surgery with that of standard phacoemulsification and no energy at all used on posterior capsule opacification (PCO) in vitro.

SETTING

Cell and Molecular Biology Research Laboratory, Department of Ophthalmology, Ludwig-Maximilians-University Munich, Real Eyes, Ophthalmology Center, Munich, and Institute for Clinical Pathology, Goethe University Frankfurt, Frankfurt, Germany.

DESIGN

Experimental study.

METHODS

Fifteen cadaver capsular bags were cultivated from 8 human donors under standard cell culture conditions. For preparation of the capsular bag, 4 groups were established as follows: femtosecond laser-assisted cataract surgery standard energy (n = 3), femtosecond laser-assisted cataract surgery high energy (n = 3), phacoemulsification (n = 6), and hydrodissection without energy (extracapsular cataract extraction) (n = 3). Growth of lens epithelial cells was observed and photodocumented. The days until full cell coverage of the posterior capsule were documented. Capsular bags were stained for fibronectin, α-smooth muscle actin, and collagen type 1.

RESULTS

Cell growth patterns in all treatment groups were comparable, with no statistically significant differences detected at any timepoint measured (P = .81, Kruskal-Wallis). The markers for fibrosis were equally distributed in all groups, indicating an equal fibrotic reaction in all groups.

CONCLUSION

Femtosecond laser-assisted cataract surgery did not increase different cellular responses in PCO formation comparison with phacoemulsification in vitro, even when higher laser pulse energy levels were used.

Refractive Outcomes After Femtosecond Laser-Assisted Cataract Surgery in Eyes With Anterior Chamber Phakic Intraocular Lenses

PURPOSE

To report the efficacy, predictability, and safety of femtosecond laser-assisted cataract surgery (FLACS) in eyes with anterior chamber phakic intraocular lenses (IOLs).

METHODS

This retrospective case series included eyes with previous implantation of an angle-supported and an iris-fixated phakic IOL for the correction of myopia that underwent a combined procedure of phakic IOL ex-plantation and FLACS with in-the-bag implantation of a posterior chamber IOL. Postoperative corrected distance visual acuity (CDVA), predictability of refractive outcome, and occurrence of intraoperative and postoperative complications were analyzed.

RESULTS

Ten eyes of 7 patients with significant cataract were included: 5 eyes with an angle-supported foldable hydrophobic phakic IOL, 4 eyes with an angle-supported polymethylmethacrylate (PMMA) phakic IOL, and 1 eye with an iris-fixated PMMA phakic IOL. Mean follow-up after FLACS was 8.4 ± 5.8 months. Mean interval between phakic IOL implantation and FLACS was 11.9 ± 4.0 years. After the combined procedure of phakic IOL explantation and FLACS, mean manifest refractive spherical equivalent (MRSE) was -0.11 ± 0.49 diopters (D) and MRSE was within ± 0.75 D of target refraction in all eyes. Four eyes received a toric posterior chamber IOL after phacoemulsification. Mean preoperative CDVA of 0.40 ± 0.23 logMAR improved significantly to 0.22 ± 0.11 logMAR postoperatively (P = .027). No intraoperative or postoperative complications occurred.

CONCLUSIONS

The results in this series showed that FLACS in eyes with previous implantation of both rigid and foldable anterior chamber phakic IOLs offers good refractive outcomes with a high level of predictability and safety. [J Refract Surg. 2018;34(5):338-342.].