Intraindividual Comparison of an Enhanced Monofocal and an Aspheric Monofocal Intraocular Lens of the Same Platform

PURPOSE

To compare intraindividual differences in visual performance of a monofocal and enhanced monofocal intraocular lens (IOL) of the same platform.

DESIGN

Prospective, interventional, fellow-eye comparison clinical study.

METHODS

In total, 55 patients (110 eyes) with bilateral age-related cataract were enrolled. All patients received a monofocal ZCB00 IOL in the dominant and an enhanced monofocal Eyhance ICB00 IOL in the nondominant eye. After 2 to 4 months, monocular best-corrected distant visual acuity (BCDVA), distance-corrected intermediate visual acuity (DCIVA), distance-corrected near visual acuity (DCNVA), contrast visual acuity, monocular defocus curves, internal higher-order aberrations (HOAs) and spherical aberrations (SA), decentration, and tilt were compared.

RESULTS

The monocular mean BCDVA, DCIVA at 80 cm and 66 cm, and DCNVA were -0.03 ± 0.07, 0.24 ± 0.12, 0.32 ± 0.13, and 0.50 ± 0.13 logarithm of the minimum angle of resolution for the enhanced ICB00 and -0.06 ± 0.06 (P = .014), 0.30 ± 0.11 (P = .005), 0.38 ± 0.12 (P = .004), and 0.55 ± 0.14 (P = .034) logarithm of the minimum angle of resolution for the ZCB00, respectively. Internal HOAs (P = .001) and negative SA (P < .001) were increased with the ICB00 at 3 mm and comparable at 5 mm (P > .05). Contrast acuity, tilt, and decentration were similar (P > .05).

CONCLUSIONS

Significantly increased monocular DCIVA at 80 cm and 66 cm and DCNVA at 40 cm were observed with the enhanced ICB00 IOL, and the ZCB00 IOL demonstrated better BCDVA. This would result in a mean gain of 2 to 3 Early Treatment of Diabetic Retinopathy Study letters at near and intermediate distance. Monocular defocus curves displayed highest differences of 5 Early Treatment of Diabetic Retinopathy Study letters at -1.25 diopters (D) and -1.50 D levels of defocus and a depth of focus of 1.23 D for the ICB00 IOL and 0.94 D for the ZCB00 IOL. Decentration, tilt, and HOAs were generally low.

Influence of a Capsular Tension Ring on Capsular Bag Behavior of a Plate Haptic Intraocular Lens: An Intraindividual Randomized Trial

PURPOSE

To evaluate the influence of a capsular tension ring (CTR) on rotational stability, decentration, tilt, and axial stability of an 11.0-mm plate haptic intraocular lens (IOL).

DESIGN

Intraindividual, randomized, double-masked, controlled clinical trial.

PARTICIPANTS

Patients scheduled for sequential same-day bilateral cataract surgery.

METHODS

All patients were randomized to receive a CTR and a plate haptic IOL in one eye and a plate haptic IOL in the fellow eye only. Intraocular lens axis assessment was performed at the end of surgery, 1 hour, 1 week, 1 month, and 6 months using a high-precision evaluation method. Decentration and tilt of the crystalline and pseudophakic lenses were assessed before surgery and at 1 week and 6 months using an anterior segment OCT.

MAIN OUTCOME MEASURES

Rotational stability from the end of surgery to 6 months and at all follow-up visits, decentration and tilt at 6 months, and differences in axial shift between 1 week and 6 months.

RESULTS

One hundred thirty eyes of 65 patients were included in the study. Absolute rotation from the end of surgery to 6 months was 2.8 ± 3.9° and 3.2 ± 5.3° for the CTR and control groups, respectively (P = 0.613). Intraocular lens decentration and IOL tilt at 6 months were 0.29 ± 0.1 mm and 0.24 ± 0.1 mm and 6.7 ± 2.8° and 5.6 ± 1.6° for the CTR and control groups, respectively (P = 0.058; P < 0.01). A posterior IOL shift of 0.31 ± 0.31 mm and 0.19 ± 0.14 mm was observed in the CTR and control groups, respectively.

CONCLUSIONS

Concomitant implantation of a CTR and a plate haptic IOL did not improve the overall rotational stability of the IOL compared with the control group. Against expectations, higher values of decentration, tilt, and axial shift were observed in the CTR group. The simultaneous use of a CTR and a plate haptic IOL in the absence of zonular weakness at the time of cataract surgery should be considered with caution.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Long-term impact of low-energy femtosecond laser and manual cataract surgery on macular layer thickness: A prospective randomized study

PURPOSE

To evaluate change in retinal layers 18 months after femtosecond laser-assisted cataract surgery (LCS) and manual cataract surgery (MCS) in a representative age-related cataract population using artificial intelligence (AI)-based automated retinal layer segmentation.

METHODS

This was a prospective, randomized and intraindividual-controlled study including 60 patients at the Medical University of Vienna, Austria. Bilateral same-day LCS and MCS were performed in a randomized sequence. To provide insight into the development of cystoid macular oedema (CME), retinal layer thickness was measured pre-operatively and up to 18 months post-operatively in the central 1 mm, 3 mm and 6 mm.

RESULTS

Fifty-six patients completed all follow-up visits. LCS compared to MCS did not impact any of the investigated retinal layers at any follow-up visit (p > 0.05). For the central 1 mm, a significant increase in total retinal thickness (TRT) was seen after 1 week followed by an elevated plateau thereafter. For the 3 mm and 6 mm, TRT increased only after 3 weeks and 6 weeks and decreased again until 18 months. TRT remained significantly increased compared to pre-operative thickness (p < 0.001). Visual acuity remained unaffected by the macular thickening and no case of CME was observed. Inner nuclear layer (INL) and outer nuclear layer (ONL) were the main causative layers for the total TRT increase. Photoreceptors (PR) declined 1 week after surgery but regained pre-operative values 18 months after surgery.

CONCLUSION

Low-energy femtosecond laser pre-treatment did not influence thickness of the retinal layers in any topographic zone compared to manual high fluidic phacoemulsification. TRT did not return to pre-operative values 18 months after surgery. The causative layers for subclinical development of CME were successfully identified.

Systematic and objective wet-lab testing of instruments for phacoemulsification: new Formalin Quadrant Model

PURPOSE

To validate an improved wet-lab model for systematic and objective efficiency testing of instruments for phacoemulsification.

SETTING

Institute of Medical Engineering, Lucerne University of Applied Sciences and Arts, Lucerne, Switzerland.

DESIGN

Experimental study.

METHODS

Porcine lenses were incubated for different time spans in formalin to simulate different cataract densities. Lenses were cut in quadrants and emulsified in a silicone test chamber. The use of ultrasound was restricted to full occlusion and the minimal power needed to promote emulsification. Equivalence to the surgical situation and cataract consistency were judged by an experienced surgeon. Efficiency was rated by effective phacoemulsification time, liquid consumption, and total surgery time.

RESULTS

Formalin incubation times of 2 hours, 1.25 hours, and 0.5 hours were validated for hard, middle-hard, and soft cataracts, respectively. Systematic testing of different fluidics settings revealed the unique opportunities of the improved model: Experiments could be performed by laboratory staff without any surgical experience after a short training, and the model provided results in a fast and reproducible manner. Reduced effective phacoemulsification time, shorter total surgery time, and less liquid consumption were observed with higher fluidics settings, confirming and complementing earlier clinical findings.

CONCLUSIONS

The Formalin Quadrant Model can be used to test new designs of instrumentation on different cataract densities or various instrument settings for efficiency. Using a validated cataract substitute, it closely represents the clinical situation and thus renders valid results in a short time. Instruments can be tested and improved profoundly before costly and elaborate clinical trials have to be applied.

Clinical prospective intra-individual comparison after mix-and-match implantation of a monofocal EDOF and a diffractive trifocal IOL

OBJECTIVES

To assess intra-individually visual acuity (VA) and subjective outcome after mix-and-match implantation of a monofocal EDOF IOL and a diffractive trifocal IOL.

METHODS

The monofocal EDOF Isopure IOL was implanted in the dominant eye and the trifocal FineVision HP IOL in the non-dominant eye. Postoperative evaluation included VA at various distances, contrast acuity, monocular defocus curves, decentration and tilt, wavefront aberrometry, VF-7 questionnaire and a halo and glare simulator.

RESULTS

50 eyes of 25 subjects were enroled. The trifocal IOL performed better at monocular DCNVA (p < 0.01) and at defocus levels of -1.5D to -4.0D (p < 0.01), the monofocal EDOF IOL was better at -0.5D (p = 0.013). No differences in monocular BCDVA, DCIVA, contrast acuity, decentration or tilt were observed (p > 0.05). Wavefront analysis revealed lower HOAs in the trifocal group at 5 mm (p < 0.01) and no difference (p = 0.107) at 3 mm pupil aperture. The monofocal EDOF IOL displayed increased negative SA at 5 mm (p < 0.01) and 3 mm (p < 0.01) pupil diameter. Low values of optical phenomena and satisfying results of the VF-7 questionnaire were obtained.

CONCLUSION

Excellent visual performance and low rates of optical phenomena were achieved after mix-and-match implantation of the monofocal EDOF Isopure IOL and the trifocal FineVision HP IOL. Trifocal IOL implantation in the non-dominant eye may decrease optical disturbing phenomena. Similar results were observed for monocular distance, intermediate and contrast VA. The trifocal IOL provided better monocular near VA. Decentration and tilt and HOAs were low.

Best fit formula approach in delayed sequential bilateral cataract surgery

BACKGROUND

We evaluated whether the best-fit intraocular lens (IOL) power formula for the first operated eye (BF1) was also the most accurate formula for the second eye.

METHODS

This was a retrospective study of 152 patients who underwent uncomplicated delayed bilateral cataract surgery with a minimum delay of 3 weeks using only one 1-piece IOL (HOYA, Vivinex) at the Medical University of Vienna, Austria. Seven different formulae (Barrett Universal II, Castrop, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T) were investigated to test the formula selection approach with regard to the calculated mean and median absolute prediction errors (MAE/MedAE).

RESULTS

The mean intraindividual difference in axial length was 0.2 mm (±0.3 mm). BF1 coincided with the best-fit formula for the second eye (BF2) in 56% of patients (p < 0.05). Using BF1 for the second eye led to a lower MedAE (0.22 dioptre, D) than using a formula at random (0.33 D) and was less accurate than using the best-fit formula for each eye separately (0.1 D). The MedAEs of all formulae were generally low, ranging from 0.28 to 0.35 D.

CONCLUSION

Using BF1 for the second eye led to a lower MedAE than the random selection of a formula. Therefore, BF1 can be used for the second eye if the surgeon is unsure of the choice of formula.

Rotational Stability, Decentration, and Tilt of a New Hydrophobic Acrylic Intraocular Lens Platform

PURPOSE

To evaluate rotational stability, decentration and tilt of the monofocal intraocular lens (IOL) Nanex (NC1-SP; HOYA Surgical Optics).

DESIGN

Prospective interventional case series.

METHODS

The study was performed at the Department of Ophthalmology, Medical University of Vienna. The study population comprised 130 eyes of 68 patients with age-related cataract who underwent cataract surgery with implantation of a Nanex IOL. Baseline image for rotational stability evaluation was obtained at the end of surgery (EoS) and compared to retroillumination images taken at 1 hour, 1 week, 1 month, and 6 months after surgery. Axis alignment was assessed using nonmovable landmarks on the sclera and the optic-haptic junctions of the IOL. Anterior segment OCT images were performed to evaluate decentration and tilt. The main outcome measure was absolute rotation from EoS to 6 months postoperatively.

RESULTS

Median IOL rotation of all eyes from EoS to 6 months was 1.9° (interquartile range 0.1°-37.5°). Ten eyes (9.71%) rotated more than 5° and 2 eyes (1.94%), more than 10°. IOL rotation did not correlate with axial eye length (Spearman r = -0.042, P = .46), crystalline lens thickness (Spearman r = 0.134, P = .19), and crystalline lens equatorial diameter (Spearman r = 0.101, P = .325). IOL rotation positively correlated with anterior fibrosis severity (Spearman r = 0.321, P = .002). Preoperative decentration (0.2 ± 0.12 mm) and tilt (5.7 ± 1.6°) did not change significantly after surgery (0.22 ± 0.12 mm and 5.62 ± 1.49°, respectively).

CONCLUSION

The investigated IOL presented good rotational stability and low decentration and tilt values. Nevertheless, anterior capsule fibrosis development led to a higher tendency of IOL rotation after 1 week.

Prostaglandin Release After Low-Energy Femtosecond Laser-Assisted Cataract Surgery Without Anti-Inflammatory Drug Premedication

PURPOSE

To compare prostaglandin E2 (PGE-2) levels in the aqueous and pupil diameter in patients undergoing low-pulse energy femtosecond laser-assisted cataract surgery (LCS) without non-steroidal anti-inflammatory (NSAID) pretreatment with either fragmentation or capsulotomy performed first.

DESIGN

Prospective, randomized, fellow-eye controlled comparison.

METHODS

This study was undertaken at the Department of Ophthalmology, Medical University of Vienna. The population consisted of 140 eyes of 70 patients with bilateral age-related cataract. Bilateral same-day LCS with either anterior capsulotomy before lens fragmentation (Caps-First) in one eye or vice versa (Frag-First) in a random sequence were performed. Aqueous was tapped 5 minutes after LCS and PGE-2 concentration was analyzed. Pupil diameters were recorded immediately before and after femtosecond laser pretreatment. The main outcome measure was PGE-2 concentrations in picograms/milliliter and pupil diameter in millimeters.

RESULTS

Mean PGE-2 concentrations were 42.0 ± 63.7 pg/mL in the Caps-First group versus 71.8 ± 160.7 pg/mL with the Frag-First group (P = .186). Mean pupil diameters before and after pretreatment were 7.6 ± 0.8 mm and 7.6 ± 0.8 mm, respectively (P = .871). Mean PGE-2 concentrations and pupil diameters did not show any significant difference between time points or groups.

CONCLUSIONS

Low-energy femtosecond laser pretreatment did not increase PGE-2 levels in the absence of NSAID pretreatment. This was independent of whether capsulotomy or fragmentation was performed first. Moreover, no pupillary miosis was observed.

Automatic segmentation of intraocular lens, the retrolental space and Berger's space using deep learning

PURPOSE

To develop and validate a deep learning model to automatically segment three structures using an anterior segment optical coherence tomography (AS-OCT): The intraocular lens (IOL), the retrolental space (IOL to the posterior lens capsule) and Berger's space (BS; posterior capsule to the anterior hyaloid membrane).

METHODS

An artificial intelligence (AI) approach based on a deep learning model to automatically segment the IOL, the retrolental space, and BS in AS-OCT, was trained using annotations from an experienced clinician. The training, validation and test set consisted of 92 cross-sectional OCT slices, acquired in 47 visits from 41 eyes. Annotations from a second experienced clinician in the test set were additionally evaluated to conduct an inter-reader variability analysis.

RESULTS

The AI model achieved a Precision/Recall/Dice score of 0.97/0.90/0.93 for IOL, 0.54/0.65/0.55 for retrolental space, and 0.72/0.58/0.59 for BS. For inter-reader variability, Precision/Recall/Dice values were 0.98/0.98/0.98 for IOL, 0.74/0.59/0.62 for retrolental space, and 0.58/0.57/0.57 for BS. No statistical differences were observed between the automated algorithm and the inter-reader variability for BS segmentation.

CONCLUSION

The deep learning model allows for fully automatic segmentation of all investigated structures, achieving human-level performance in BS segmentation. We, therefore, expect promising applications of the algorithm with particular interest in BS in automated big data analysis and real-time intra-operative support in ophthalmology, particularly in conjunction with primary posterior capsulotomy in femtosecond laser-assisted cataract surgery.

Ultrasound energy consumption and macular changes with manual and femtolaser-assisted high-fluidics cataract surgery: a prospective randomized comparison

PURPOSE

The purpose of the study was to compare ultrasound (US) consumption and central macular thickness (CMT) and volume changes with manual and femtosecond laser (FSL)-assisted cataract nucleus workup.

METHODS

Sixty patients scheduled for immediate sequential bilateral surgery underwent a prospective randomized intraindividual comparison of nucleus sector fragmentation performed manually in one eye and with low-energy FSL assistance in the partner eye, followed by high-fluidics phacoaspiration with a maximum US power of 30%. Ultrasound (US) energy consumption and macular thickness and volume were compared as measured by intraoperative effective phacoemulsification time (EPT) and high-resolution spectral domain optical coherence tomography pre- and 1 week, 3 weeks and 6 weeks postoperatively. Results are presented as means ± SD or medians [min; max].

RESULTS

Fifty-two patients completed the full follow-up. For the manual and FSL-assisted groups, nuclear hardness was almost identical with a mean LOCS III grade of 2.44 ± 1.08 and 2.50 ± 1.00 (p = 0.371). Median EPT was 1.40 [0.2; 8.3] and 1.25 [0.2; 9.4] seconds. Median preoperative CMT was 276.50 [263.25; 289.75] µm and 276.00 [262.00; 290.00] µm. Median postoperative CMT was 278.00 [260.50; 288.00] versus 275.50 [264.00; 290.50] µm at 1 week, 279.50 [266.75; 292.25] versus 280.00 [266.50; 294.50] µm at 3 weeks and 280.50 [268.00, 293.75] versus 279.50 [264.75; 295.25] µm at 6 weeks. Differences in CMT and total macular volume between the groups were not statistically significant at any point in time.

CONCLUSION

Femtosecond laser (FSL) prefragmentation of the nucleus into six sectors did not reduce US energy consumption compared with manual splitting of the nucleus into four quadrants in this particular surgical setting. Sectorial FSL-prechopping with the low-energy FSL used had no additional impact on postoperative macular thickness and volume.

Back-calculation of keratometer index based on OCT data and raytracing - a Monte Carlo simulation

PURPOSE

This study aims to develop a raytracing-based strategy for calculating corneal power from anterior segment optical coherence tomography data and extracting the individual keratometer index, which converts the corneal front surface radius to corneal power.

METHODS

A large OCT dataset (10,218 eyes of 8,430 patients) from the Casia 2 (Tomey, Japan) was post-processed in MATLAB (MathWorks, USA). Radius of curvature, asphericity of the corneal front and back surface, central corneal thickness and pupil size (aperture) were used to trace a bundle of rays through the cornea and derive the best focus plane. Corneal power was calculated with respect to the corneal front vertex plane, and the keratometer index was back-calculated using corneal power and front surface radius. Keratometer index was analysed in a multivariate linear model.

RESULTS

The averaged resulting keratometer index was 1.3317 ± 0.0017 with a median of 1.3317 and range from 1.3233 to 1.3390. In a univariate model, only the front surface asphericity affected the keratometer index. The multivariate model for modelling the keratometer index using all 6 input parameters performed very well (RMS error: 5.54e-4, R² : 0.90, significance vs. constant model: <0.0001).

CONCLUSIONS

In the classical calculation, the keratometer index used for converting corneal radius to dioptric power uses several model assumptions. As these assumptions are not generally satisfied, corneal power cannot be calculated from corneal front surface radius alone. Considering all 6 input variables, the linear prediction model performs well and can be used if all input parameters are measured with a tomographer.

Rotational Stability of Intraocular Lenses: A Standardized Method for More Accurate Measurements in Future Studies

PURPOSE

To assess the reliability and reproducibility of a new semiautomated evaluation method, "Rotix," for intraocular lens (IOL) rotation and to define a standardized evaluation method for future toric IOL studies.

DESIGN

Reliability and reproducibility study.

METHODS

Setting: Department of Ophthalmology, Medical University of Vienna.

PATIENT POPULATION

A dataset of 25 patients with 2 consecutive follow-up visits was created to test the intra- and interrater reliability. A data test set of 10 patients including 30 pictures taken 5 minutes apart was created to test the short-term reproducibility.

INTERVENTION

Evaluation of IOL rotational stability using nontoric implants in 25 × 2 consecutive follow-up visits. Two experienced graders performed axis evaluation 3 times in a randomized order. One experienced grader performed axis evaluation for the short-term reproducibility study. Reference landmarks at the end of operation were used to assess the IOL axis.

MAIN OUTCOME MEASURES

Intra- and interrater reliability and short-term reproducibility of axis measurements.

RESULTS

Mean standard deviation for intrarater reliability was 0.16 degrees. The intraclass correlation coefficients were 0.97 for grader 1 and 0.96 for grader 2. A very high interrater correlation of 0.95 was found. The mean individual difference between grader 1 and grader 2 was 0.061 ± 0.28 degrees. Short-term reproducibility showed a mean standard deviation of 0.22 ± 0.14 degrees.

CONCLUSION

The novel semiautomated evaluation method showed an accurate inter- and intrarater reliability. Short-term reproducibility was below 0.25 degrees. The method of using nonmovable reference landmarks showed reliable results and should be used as a standard in future toric IOL studies.

Comparison of Axis Determination With Different Toric Intraocular Lens Power Calculation Methods

PURPOSE

To compare the axis position of the measured total corneal astigmatism (TCA) with the axis of the anterior keratometry and the calculated axis position of different toric intraocular lens (IOL) calculators.

METHODS

A total of 163 astigmatic eyes of 163 patients were retrospectively analyzed. The axis of the actual TCA, measured with anterior segment optical coherence tomography, was compared to the anterior keratometric value (Group I) and three different methods of TCA calculation for toric IOL power determination: Abulafia-Koch regression formula (Group II), Barrett Toric Calculator V2.0 (Group III), and Barrett Toric Calculator V2.0 including measured posterior keratometric value (Group IV). Eyes were assigned to three subgroups: with-the-rule, against-the-rule, and oblique astigmatism.

RESULTS

The mean deviation calculated from measured TCA was +0.56° (Group I), -0.32° (Group II), -0.37° (Group III), and -1.00° (Group IV). For with-the-rule astigmatism, the TCA axis agreed most with Group I (6.5% outliers > 5° deviation). For against-the-rule astigmatism, Group IV and Group II were closest to the measured TCA axis (1.5% and 3% outliers with > 5° deviation).

CONCLUSIONS

The means of the calculated axis were similar to the measured TCA, but the proportion of outliers with an axis deviation of greater than 5° showed remarkable differences. Isolated anterior keratometric value measurements showed the fewest outliers in with-the-rule astigmatism. In against-the-rule astigmatism, Abulafia-Koch calculation should be used for axis determination. [J Refract Surg. 2021;37(9):642-647.].

Lasting Effects: Seven Year Results of the Castrop Nomogram for Femtosecond Laser-Assisted Paired Corneal Arcuate Incisions

PURPOSE

Long-term results of arcuate incisions are rarely reported. This is unfortunate as long-term stability of astigmatic correction is of great interest to surgeons performing astigmatic correction. This study investigates the 7 year stability of results after application of femtosecond laser-assisted arcuate incisions with the Castrop nomogram.

METHODS

Prospective interventional case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Single site, single surgeon study. Seven year results of cataract patients with low to moderate corneal astigmatism receiving femtosecond laser-assisted arcuate incisions using a TechnolasVictus SW 2.7 (Bausch & Lomb Inc, Dornach, Germany) were assessed and compared to 1 year results. Outcome evaluation was based on astigmatic vector analysis, manifest refraction, and visual acuity.

RESULTS

The study analyzed 19 eyes of 19 patients 7 years after surgery. Ocular residual astigmatism changed from -0.26 to -0.39 D. Preoperative corneal astigmatism was -1.51 D. Correction Index changed from 1.0 to 1.16. The magnitude of difference vector changed from 0.26 to 0.39 D. The index of success changed from 0.20 to 0.29. Spherical equivalent remained stable. A slight tendency to change toward astigmatic overcorrection was mainly observed for patients with preoperative with the rule astigmatism, but not with patients with against the rule astigmatism.

CONCLUSIONS

The Castrop nomogram showed stable results 7 years after surgery. Similar to toric IOL surgery, it is advisable to be less aggressive when correcting with the rule astigmatism, to avoid overcorrection over a long period.

Rotational Stability of a New Hydrophobic Acrylic IOL With Modified C-loop Haptics

PURPOSE

To assess rotational stability, axial stability, decentration, and tilt of the Rayner RAO800C single-piece hydrophobic acrylic intraocular lens (IOL) (Rayner Intraocular Lenses Ltd) from end of surgery to 4 to 7 months postoperatively.

METHODS

Surgeries were performed at the Department of Ophthalmology at the Medical University of Vienna. A total of 130 eyes of 68 patients received an aspheric hydrophobic Rayner RAO0800C IOL. IOLs were randomly implanted to the 0 ± 10, 45 ± 10, 90 ± 10, or 135 ± 10 degree axis. Baseline measurement was performed with the patient still supine on the operating table. Axis alignment after 1 hour, 1 week, 1 month, and 4 months was evaluated by retroillumination pictures. Postoperative IOL decentration, tilt, and aqueous depth at 4 months were assessed using an anterior segment swept-source optical coherence tomography.

RESULTS

Absolute median IOL rotation from end of surgery to 4 months was 2.4 degrees (range: 0.0 to 85.0 degrees). Median IOL rotation from end of surgery to 1 hour, 1 hour to 1 week, 1 week to 1 month, and 1 month to 4 months was 1.6 (range: 0.0 to 86.2), 1.1 (range: 0.0 to 28.8), 0.6 (range: 0.0 to 5.2), and 0.7 (range: 0.0 to 2.6) degrees. Respective proportions of IOLs rotating more than 5, 10, and 20 degrees from end of surgery to 4 months were 23.9%, 11.0%, and 6.4%. Horizontal and vertical decentration at 4 months was -0.09 ± 0.14 and 0.09 ± 0.14 mm, respectively. Horizontal and vertical tilt at 4 months was -4.78 ± 1.36 and -1.58 ± 1.10 degrees, respectively. A posterior axial shift of 0.052 ± 0.055 mm was observed from 1 week to 4 months.

CONCLUSIONS

Although median IOL rotation appeared to be low, a significant proportion of IOLs rotated postoperatively. Decentration and tilt values were generally low. A minimal posterior optic shift was observed after 1 week. [J Refract Surg. 2021;37(2):112-118.].

Calculation of ocular magnification in phakic and pseudophakic eyes based on anterior segment OCT data

PURPOSE

The purpose of this study is to develop a straightforward mathematical concept for determination of object to image magnification in both phakic and pseudophakic eyes, based on biometric measures, refractometry and data from an anterior segment optical coherence tomography (OCT).

METHODS

We have developed a strategy for calculating ocular magnification based on axial length measurement, phakic anterior chamber and lens thickness, keratometry and crystalline lens front and back surface curvatures for the phakic eye, and axial length measurement, anterior chamber and lens thickness, keratometry and intraocular lens power, refractive index and shape factor for the pseudophakic eye. Comparing the magnification of both eyes of one individual yields aniseikonia, while comparing the preoperative and postoperative situation of one eye provides the gain or loss in ocular magnification. The applicability of this strategy is shown using a clinical example and a small case series in 78 eyes of 39 patients before and after cataract surgery.

RESULTS

For the phakic eye, the refractive index of the crystalline lens was adjusted to balance the optical system. The pseudophakic eye is fully determined and we proposed three strategies for considering a potential mismatch of the data: (A) with spherical equivalent refraction, (B) with intraocular lens power and (C) with the shape factor of the lens. Magnification in the phakic eye was -0.00319 ± 0.00014 and with (A) was -0.00327 ± 0.00013, with (B) was -0.00323 ± 0.00014 and with (C) was -0.00326 ± 0.00013. With A/B/C, the magnification of the pseudophakic eye was on average 2.52 ± 2.83%/1.31 ± 2.84%/2.14 ± 2.80% larger compared with the phakic eye. Magnification changes were within a range of ±10%.

CONCLUSIONS

On average, ocular magnification does not change greatly after cataract surgery with implantation of an artificial lens, but in some cases, the change could be up to ±10%. If the changes are not consistent between the left and right eyes, then this could lead to post-cataract aniseikonia.

One-Year Results of Arcuate Keratotomy in Patients With Low to Moderate Corneal Astigmatism Using a Low-Pulse-Energy Femtosecond Laser

PURPOSE

To investigate corneal astigmatism (CA) reduction and corneal optical quality after surface-penetrating femtosecond laser arcuate keratotomies (Femto AK) considering anterior (CA_ant) and posterior corneal curvature (CA_post), total corneal refractive power astigmatism (CA_tot), and corneal higher-order aberrations (HOAs) through 1 year.

DESIGN

Prospective interventional case series.

METHODS

Setting: Department of Ophthalmology, Medical University of Vienna. PatientPopulation: Forty-three eyes of 43 patients with age-related cataract and CA_tot between 1 and 3 diopters (D).

INTERVENTION

Paired keratotomies were created with a low-energy femtosecond laser (LDV Z8; Ziemer Ophthalmic Systems, Port, Switzerland) and combined with an astigmatic neutral manual posterior-limbal cataract incision. CA and HOAs measurements were obtained preoperatively and after 1 month, 3 months, and 1 year. MainOutcomeMeasure: Change of CA and HOAs after low-energy Femto AK through 1 year.

RESULTS

Mean preoperative CA_ant and CA_tot (1.62 ± 0.49 D and 1.58 ± 0.44 D) were significantly reduced, to 0.66 ± 0.38 and 0.50 ± 0.30 D (P < .001) 1 year after surgery, respectively. CA_post showed no significant change, from 0.31 ± 0.19 D preoperatively to 0.31 ± 0.13 D (P = .732) at the 1-year follow-up period. Astigmatism as calculated by vector astigmatism analysis stayed stable at 1 month, 3 months, and 1 year. Corneal wavefront HOAs significantly improved at 1 month, 3 months, and 1 year.

CONCLUSIONS

Paired surface-penetrating keratotomies created by a low-energy femtosecond laser showed efficient and stable CA reduction within 1 year after surgery. The optical quality of the cornea was preserved with lower HOAs than preoperatively.

Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data

Purpose

To analyse corneal power based on a large optical coherence tomography dataset using raytracing, and to evaluate corneal power with respect to the corneal front apex plane for different definitions of best focus.

Methods

A large OCT dataset (10,218 eyes of 8,430 patients) from the Casia 2 (Tomey, Japan) was post-processed in MATLAB (MathWorks, USA). Using radius of curvature, corneal front and back surface asphericity, central corneal thickness, and pupil size (aperture) a bundle of rays was traced through the cornea. Various best focus definitions were tested: a) minimum wavefront error, b) root mean squared ray scatter, c) mean absolute ray scatter, and d) total spot diameter. All 4 target optimisation criteria were tested with each best focus plane. With the best-fit keratometer index the difference of corneal power and keratometric power was evaluated using a multivariate linear model.

Results

The mean corneal powers for a/b/c/d were 43.02±1.61/42.92±1.58/42.91±1.58/42.94±1.59 dpt respectively. The root mean squared deviations of corneal power from keratometric power (n_K = 1.3317/1.3309/1.3308/1.3311 for a/b/c/d) were 0.308/0.185/0.171/0.209 dpt. With the multivariate linear model the respective RMS error was reduced to 0.110/0.052/0.043/0.065 dpt (R² = 0.872/0.921/0.935/0.904).

Conclusions

Raytracing improves on linear Gaussian optics by considering the asphericity of both refracting surfaces and using Snell’s law of refraction in preference to paraxial simplifications. However, there is no unique definition of best focus, and therefore the calculated corneal power varies depending on the definition of best focus. The multivariate linear model enabled more precise estimation of corneal power compared to the simple keratometer equation.

Influence of Artificial Tears on Keratometric Measurements in Cataract Patients

PURPOSE

To assess the influence of artificial tears of different viscosity on K-readings prior to cataract surgery.

DESIGN

Prospective randomized crossover, before-and-after clinical study.

METHODS

Setting: Department of Ophthalmology, Medical University of Vienna.

PATIENT POPULATION

A total of 123 eyes of 80 patients prior to cataract surgery were assigned to 2 groups based on normal and dry eyes.

INTERVENTION

Two native baseline keratometries were followed by instillation of either high- or low-viscosity eye drops. Keratometry was repeated 30 seconds, 2 minutes, and 5 minutes after instillation.

MAIN OUTCOME MEASURES

Influence of eye drops of different viscosity in normal and dry eyes on short time K-readings.

RESULTS

Repeatability between native baseline measurements was high (standard deviation = 0.02 mm in normal and in dry eyes). In normal and dry eyes, a statistically significant increase in measurement variability after instillation of both low-viscosity and high-viscosity eye drops was observed (P < .01). Measurement variability was most pronounced between baseline measurement and 30 seconds and diminished over time. Variability of K-readings appeared higher in dry eyes compared with normal eyes. Astigmatism changed more than 0.5 diopters in 13.2% of normal eyes and 34.4% in dry eyes using eye drops of high viscosity.

CONCLUSION

Tear film-stabilizing eye drops prior to keratometry measurements influenced K-readings significantly, especially in dry eyes. A time period of more than 5 minutes should be allowed to pass after instillation of eye drops. The higher the viscosity of the eye drops, the stronger the influence and the longer its persistence.

Accuracy of common IOL power formulas in 611 eyes based on axial length and corneal power ranges

AIMS

To provide clinical guidance on the use of intraocular lens (IOL) power calculation formulas according to the biometric parameters.

METHODS

611 eyes that underwent cataract surgery were retrospectively analysed in subgroups according to the axial length (AL) and corneal power (K). The predicted residual refractive error was calculated and compared to evaluate the accuracy of the following formulas: Haigis, Hoffer Q, Holladay 1 and SRK/T. Furthermore, the percentages of eyes with ≤±0.25, ≤±0.5 and 1 dioptres (D) of the prediction error were recorded.

RESULTS

The Haigis formula showed the highest percentage of cases with ≤0.5 D in eyes with a short AL and steep K (90%), average AL and steep cornea (73.2%) but also in long eyes with a flat and average K (65% and 72.7%, respectively). The Hoffer Q formula delivered the lowest median absolute error (MedAE) in short eyes with an average K (0.30 D) and Holladay 1 in short eyes with a steep K (Holladay 1 0.24 D). SRK/T presented the highest percentage of cases with ≤0.5 D in average long eyes with a flat and average K (80.5% and 68.1%, respectively) and the lowest MedAE in long eyes with an average K (0.29 D).

CONCLUSION

Overall, the Haigis formula shows accurate results in most subgroups. However, attention must be paid to the axial eye length as well as the corneal power when choosing the appropriate formula to calculate an IOL power, especially in eyes with an unusual biometry.

[Combination of lens decentration and tilt in phakic and pseudophakic eyes-Optical simulation of defocus, astigmatism and coma]

BACKGROUND AND PURPOSE

The effect of lens decentration and tilt on retinal image quality has been extensively studied in the past in simulations and clinical studies. The purpose of this study was to analyze the effect of combined lens decentration and tilt on the induction of defocus, astigmatism and coma in phakic and pseudophakic eyes.

METHODS

Simulations were performed with Zemax on the Liou-Brennan schematic model eye. Based on the position of the gradient lens the image plane was determined (best focus). The lens was decentered horizontally from -1.0 mm to 1.0 mm in steps of 0.2 mm and tilted with respect to the vertical axis from -10° to 10° in steps of 2° (in total 121 combinations of decentration and tilt). For each combination of decentration and tilt defocus, astigmatism (in 0/180°) and horizontal coma was extracted from wave front error and recorded for a pupil size of 4 mm. After replacement of the gradient lens with an aberration correcting artificial lens implant model with the equatorial plane of the artificial lens aligned to the equatorial plane of the gradient lens, the simulations were repeated for the pseudophakic eye model.

RESULTS

For the lens positioned according to the Liou-Brennan schematic model eye the simulation yielded a defocus of 0.026 dpt/-0.001 dpt, astigmatism of -0.045 dpt/-0.018 dpt, and a coma of -0.015 µm/0.047 µm for phakic/pseudophakic eyes. Maximum values were observed for a horizontal decentration of 1.0 mm and a tilt with respect to the vertical axis of 10° with 1.547 dpt/2.982 dpt for defocus, 0.971 dpt/1.871 dpt for astigmatism, and 0.441 µm/1.209 µm for coma. Maximum negative values occurred in phakic/pseudophakic eyes with -0.293 dpt/-1.224 dpt for defocus, for astigmatism -0.625 dpt/-0.663 dpt and for coma -0.491 µm /-0.559 µm, respectively.

CONCLUSION

In this simulation study the effect of a combination of lens decentration in horizontal direction and tilt with respect to the vertical axis on defocus, astigmatism and horizontal coma was analyzed. The results may help to describe in clinical routine if with a decentered or tilted artificial lens implant the postoperative refraction does not match the target refraction or the resulting astigmatism after cataract surgery is not fully explained by measurement of corneal astigmatism.

Posterior Capsule Opacification With Two Hydrophobic Acrylic Intraocular Lenses: 3-Year Results of a Randomized Trial

PURPOSE

To compare the incidence and intensity of posterior capsule opacification (PCO) and neodymium-yttrium-aluminum-garnet (Nd:YAG) capsulotomy rates between 2 similar open-loop single-piece hydrophobic acrylic intraocular lenses (IOLs) that differ in the proprietary material characteristics and design features, over a period of 3 years.

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

METHODS

Setting: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

PATIENT POPULATION

Eighty patients (160 eyes) had bilateral cataract surgery and received a Vivinex XY1 IOL in 1 eye and an AcrySof SN60WF IOL in the other eye.

OBSERVATION PROCEDURES

Follow-up examinations were performed 3 years after surgery. Digital retroillumination images were taken of each eye. The amount of PCO (score: 0-10) was assessed subjectively at the slit lamp and objectively using automated image analysis software (AQUA).

MAIN OUTCOME MEASURE

PCO score (scale, 0-10).

RESULTS

The mean objective PCO score of the Vivinex XY1 IOLs was 0.9 ± 0.8 compared to the PCO score of 1.4 ± 1.1 for the AcrySof SN60WF IOLs (P < .001). Three years postoperatively, 11.4% of patients had an Nd:YAG capsulotomy in the Vivinex XY1 eye and 18.6% had a capsulotomy in the AcrySof SN60WF eye (P = .23).

CONCLUSION

The new hydrophobic acrylic Vivinex XY1 IOL showed significantly lower PCO rates and lower YAG rates compared to the AcrySof SN60WF IOL. The interaction of various factors such as hydrophobic material, smooth optic surface, and sharp posterior optic edge plays a key role in PCO development.

Posterior capsule opacification and Nd:YAG laser rates with two hydrophobic acrylic single-piece IOLs

OBJECTIVES

To evaluate the development of posterior capsule opacification (PCO) and Nd:YAG capsulotomy rates following implantation of two hydrophobic acrylic IOLs.

METHODS

In a randomized, controlled trial, 80 patients with bilateral senile cataract were implanted with the hydrophobic acrylic single-piece intraocular Lenses (IOLs) EyeCee One in one eye and iMics1 in the other. Outcomes of 39 patients (78 eyes) were evaluated after 3 years. Automated Quantification of After-Cataract (AQUA; for PCO occurrence), visual acuity, anterior fibrosis, capsule-optic edge interaction and distance between anterior and posterior capsule IOL surface were analysed.

RESULTS

After a mean follow-up of 38 ± 1.95 months, Nd:YAG capsulotomy occurred at a rate of 15.4% and 46.2% in the EyeCee One and iMics1 groups, respectively (p < 0.01). Respective mean PCO scores measured by AQUA were 1.57 ± 1.63 and 2.45 ± 1.44 (p = 0.019). A distinct gap between the anterior capsule and the IOL optic was present in 89% of eyes implanted with EyeCee One and 13% of iMics1 eyes. A gap between the posterior capsule and the posterior surface of the lens was observed in 76% of EyeCee One eyes and 35% of iMics1 eyes.

CONCLUSIONS

Study findings suggest that PCO and Nd:YAG capsulotomy rates are significantly lower in eyes implanted with the EyeCee One IOL compared to the iMics1 IOL. Optic sharpness and lens material seem to be the decisive factors, while the stepped edge beneath the haptic junction appeared to be ineffective.

Comparison of posterior capsule opacification development with 2 single-piece intraocular lens types

PURPOSE

To evaluate the differences in the incidence of posterior capsule opacification (PCO) and visual and optical performance between 2 hydrophobic acrylic single-piece sharp-edged intraocular lenses (IOLs) over 3 years.

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

DESIGN

Prospective randomized case series.

METHODS

Patients with bilateral cataract were prospectively randomized to receive an Eyecee One IOL (IOL A) or an Acrysof SN60WF IOL (IOL B) and were followed for 36 months. The corrected distance visual acuity (CDVA) and IOL decentration and tilt were measured. The PCO was quantified by analysis of standardized retroillumination images.

RESULTS

The study comprised 160 eyes of 80 patients. The PCO incidence was low for both IOLs at all follow-up visits. Three years postoperatively, the median objective PCO score was 1.4 (range 0 to 5.6) for IOL A and 1.5 (range 0 to 5.0) for IOL B (P = .67). The neodymium:YAG (Nd:YAG) capsulotomy rate 3 years after surgery was 16.4% and 6.0% (P = .06), respectively. Visual acuity and contrast sensitivity outcomes were also comparable at all follow-up visits.

CONCLUSIONS

Both IOLs showed good capsular bag performance and low PCO rates 3 years after surgery. Both IOLs also showed comparable results for visual acuity, contrast sensitivity, decentration and tilt, PCO score, slitlamp examination, and Nd:YAG capsulotomy rates.

Impact of primary posterior capsulorhexis on regeneratory after-cataract and YAG laser rates with an acrylic micro-incision intraocular lens with plate haptics: 1-year and 3-year results

Purpose

To evaluate the posterior capsule opacification (PCO) and YAG laser capsulotomy (YAG‐LCT) rates with a plate‐haptic acrylic micro‐incision intraocular lens (IOL) and the impact of primary posterior capsulorhexis.

Methods

A total of 97 patients scheduled for immediate sequential bilateral cataract surgery underwent a randomized, prospective intraindividual comparison with the ZEISS Asphina 409MV plate‐haptic acrylic IOL with the eyes receiving an additional primary posterior capsulorhexis (PPCR) or not. YAG‐LCT and PCO rates were evaluated at 1 and 3 years. Three‐year PCO rates were calculated with a 3‐scenario method for eyes that underwent YAG‐LCT between 1 and 3 years.

Results

A total of 56 patients were seen at 1 year, and 57 at 3 years. For the eyes without and with PPCR, YAG‐LCT rates were 14.3% and 0% at 1 year, and 59.7% and 3.5% at 3 years, respectively. Opacification rates at 1 year were 0.55 ± 0.99 and 0.05 ± 0.21 for the central 2‐mm optic zone. A total of 42 patients completed both the 1‐ and 3‐year follow‐up. Three‐year opacification rates for the group without PPCR were 1.99 ± 2.20, 2.26 ± 2.66 and 3.66 ± 3.61 for the central 2‐mm zone and 2.57 ± 2.07, 3.13 ± 3.03 and 4.09 ± 3.34 for the 4.5‐mm zone for the best, extrapolated and worst‐case scenarios, respectively.

Conclusion

The ZEISS Asphina 409MV plate‐haptic acrylic IOL exhibited unusually high YAG‐LCT and PCO rates with standard in‐the‐bag implantation. PPCR was safe and effective in preventing central opacification and the need for YAG laser treatment.

Transzonular capsulo-hyaloidal hydroseparation with optional triamcinolone enhancement: A technique to detect or induce anterior hyaloid membrane detachment for primary posterior laser capsulotomy

Primary posterior laser capsulotomy (PPLC) requires adequate visualization and spacing of the posterior lens capsule (PLC) and anterior hyaloid membrane (AHM). After intraocular lens implantation and watertight incision hydration, the laser is redocked for optical coherence tomography reimaging. If the PLC and AHM are not imaged or interspaced adequately, transzonular capsulo-hyaloidal hydroseparation is attempted by rinsing the zonular fibers with fluid. If the PLC or AHM are still not detected or discernable, an attempt follows to mark the Berger space using diluted triamcinolone acetate. Before hydroseparation, the AHM or PLC are often invisible or variably attached. If structures cannot be defined, triamcinolone-added hydroseparation is often effective in defining the AHM and Berger space. Transzonular capsulo-hyaloidal hydroseparation with an optional triamcinolone acetate addition can initiate or complete AHM detachment and improve visibility and patency of Berger space for augmenting control and feasibility of PPLC.

True rotational stability of a single-piece hydrophobic intraocular lens

BACKGROUND

To evaluate rotation and its influencing factors of an aspheric one-piece hydrophobic acrylic intraocular lens (IOL) Vivinex XY1 during 6 months after operation.

METHODS

In this institutional trial, 122 eyes of 66 patients were implanted with a non-toric aspheric IOL Vivinex XY1 (Hoya Corporation, Tokyo, Japan). IOL alignment was assessed at the end of surgery, 1 hour, 1 week, 1 month and 6 months after implantation. Confounding factors such as axial length, presence of anterior fibrosis and randomised implantation in four different intended axes (0°, 45°, 90°, 135°) were evaluated. Decentration and tilt were measured using a Purkinje metre.

RESULTS

Assessment of rotational stability was possible for 103 of 122 implanted IOLs 6 months after eye surgery. The median absolute rotation was 1.1° (range: 0°-5°). Rotation was significantly increased within the first hour after operation compared with later time-points (p<0.001). No correlation was found with axial length and rotation (Spearman's r=0.048, p=0.63). No significant difference was observed regarding different implantation axes (p=0.75). Rotation was not influenced by the presence of anterior fibrosis (p=0.98).

CONCLUSION

Assessing the true IOL position at the end of surgery is crucial for the evaluation of rotational stability of IOLs. No IOL rotation exceeding 5° could be detected 6 months after surgery.

Interpretation der Intraokularlinsenkonstanten für die Haigis-Formel

Hintergrund Die Haigis-Formel nutzt eine lineare Regression mit 3 IOL-Konstanten für die Vorhersage der effektiven postoperativen Linsenposition (ELP) der Intraokularlinse (IOL), ELP ≈ a0 + a1 ACD + a2 L, auf Basis der präoperativen Vorderkammertiefe (ACD) und Achslänge (L).

Material und Methoden Unterschiede zwischen den IOL-Konstanten-Tripletts können anhand ihrer statistischen Messunsicherheit eingeordnet werden. Um zu untersuchen, ob die Abschätzung der mittleren ELP mithilfe der mittleren ACD und mittleren L gemäß 〈ELP〉 ≈ a0 + a1 〈ACD〉 + a2 〈L〉 eine mögliche Alternative darstellt, haben wir beide Methoden verglichen. Dazu wurden die Ergebnisse aus 2 unterschiedlichen Optimierungsstrategien für die IOL-Konstanten a0, a1, a2 für 2 unterschiedliche IOL genutzt.

Ergebnisse Die Abschätzung der mittleren ELP ist zur groben Einordnung der IOL-Konstanten geeignet. Die Konfidenzvolumina in Form von Ellipsoiden basierend auf den statistischen Messunsicherheiten der IOL-Konstanten-Optimierungen erlauben eine genauere Beurteilung der Unterschiede zwischen verschiedenen IOL-Konstanten-Tripletts a0, a1, a2.

Determination of Personalized IOL-Constants for the Haigis Formula under Consideration of Measurement Precision

The capabilities of a weighted least squares approach for the optimization of the intraocular lens (IOL) constants for the Haigis formula are studied in comparison to an ordinary least squares approach. The weights are set to the inverse variances of the effective optical anterior chamber depth. The effect of random measurement noise is simulated 100000 times using data from N = 69 cataract patients and the measurement uncertainty of two different biometers. A second, independent data set (N = 33) is used to show the differences that can be expected between both methods. The weighted least squares formalism reduces the effect of measurement error on the final constants. In more than 64% it will result in a better approximation, if the measurement errors are estimated correctly. The IOL constants can be calculated with higher precision using the weighted least squares method.

[Developments in modern cataract surgery – a critical overview]

Cataract surgery has tremendously evolved in recent years. Innovations include micro-incision cataract surgery through incisions smaller than 2mm, high-fluidics phacoaspiration and laser phacoemulsification to minimize or replace the use of ultrasound, the advent of femtolasers for high-precision incisions in the cornea, the lens capsule and the cataractous lens, aspheric intraocular lenses (IOLs) to enhance the quality and contrast of the image, multifocal and enhanced-depth-of-focus IOLs to correct presbyopia, advancements in biometry and IOL power calculation, prevention of secondary capsule opacification by improvements in the design and material of the IOLs and surgical techniques like capsule polishing and posterior capsulorhexis, and pharmacological prophylaxis and possible future treatment of the cataract itself. Finally, cost-effectiveness and future potential of same-session bilateral cataract surgery are discussed.

Posterior capsular opacification and Nd:YAG capsulotomy rates with the iMics Y-60H and Micro AY intra-ocular lenses: 3-year results of a randomized clinical trial

PURPOSE

To compare the incidence and intensity of posterior capsular opacification (PCO) and neodymium:yttrium-aluminium-garnet (Nd:YAG) capsulotomy rates between two microincision intra-ocular lenses (IOLs) 3 years after surgery.

METHODS

Sixty-five patients randomly received a Y-60H IOL (HOYA Surgical Optics, Singapore) in one eye and a Micro AY IOL (PhysIOL, Liège, Belgium) in the contralateral eye during same-day bilateral cataract surgery. Eyes were examined 1 week, 20 months and 3 years after surgery. The amount of PCO (score: 0-10) was assessed subjectively at the slit lamp and objectively using automated image analysis software (aqua). Additionally, the Nd:YAG capsulotomy rate was noted.

RESULTS

Three years postoperatively, the objective PCO score of Y-60H IOLs was 1.9 ± 1.7 compared to PCO score of 1.7 ± 2.2 for the Micro AY IOLs (p = 0.66). Thirty-four percentage of the Y-60H eyes had undergone Nd:YAG capsulotomy, compared to 49% of the Micro AY eyes (p = 0.04). Significantly, more capsular folds were observed in the Y-60H IOL group (p = 0.001). There was no significant difference in best-corrected visual acuity, rhexis/IOL overlap and anterior capsule opacification 3 years after surgery.

CONCLUSION

Both microincision IOLs showed high YAG rates and comparable PCO scores 3 years after surgery. In the light of this unsatisfying PCO performance, the advantage of the present microincision IOLs over conventional IOLs must be questioned.

Impact of low versus high fluidic settings on the efficacy and safety of phacoemulsification

PURPOSE

  To compare intraoperative efficiency and postoperative outcomes of cataract surgery with low and high fluidic settings.

METHODS

  In this prospective, randomized, single-blinded study, 114 eyes of 57 patients were operated with low fluidic settings for one eye (group I) and high fluidic settings for the other eye (group II). Efficiency was judged as metred surgery time, effective phacoemulsification time (EPT) and the amount of balanced salt solution used. Visual outcome and endothelial cell count were determined 1 week and 18 months postoperatively.

RESULTS

  The overall effective phacoemulsification energy was statistically significantly lower (p = 0.003) in group II than in group I. Conquest of the nuclei was achieved with about two-thirds of the energy needed in group I, with 6.59 ± 4.79 effective ultrasound energy compared with 3.99 ± 3.18 (p = 0.001). Overall, about 12% more solution was used in group II than in group I. Median visual acuity was 1.0 for both groups 18 months after surgery. The mean endothelial cell loss was 5.0% in eyes in group I compared with 6.3% in eyes in group II (p > 0.5).

CONCLUSION

  Switching from low fluidic settings with a conventional coaxial 20G phacoemulsification tip to higher fluidic settings with a microcoaxial phaco tip statistically significantly decreases EPT. As only marginally more solution was used with the higher aspiration flow, occlusion must be accomplished more often with high than with low fluidics. Aspiration of the quadrants was therefore more efficient with high fluidic settings. The enhanced pump speed did not result in more tissue damage.

Posterior capsule opacification with the iMics1 NY-60 and AcrySof SN60WF 1-piece hydrophobic acrylic intraocular lenses: 3-year results of a randomized trial

PURPOSE

To compare the intensity of posterior capsule opacification (PCO) 3 years after implantation of 2 different 1-piece foldable hydrophobic acrylic intraocular lenses (IOLs).

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

METHODS

One hundred patients with bilateral age-related cataract (200 eyes) had standard cataract surgery with implantation of an iMics1 NY-60 IOL (Hoya Corp) in one eye and an AcrySof SN60WF IOL (Alcon Laboratories) in the other eye. Follow-up examinations were performed at 1 week and 3 years. Digital retroillumination images were obtained of each eye. The main outcome measure was PCO score (scale, 0 to 10) assessed subjectively at the slit lamp and objectively using automated image analysis software (Automated Quantification of After-Cataract) 3 years after surgery.

RESULTS

The objective PCO score (mean ± standard deviation) was 3.0 ± 2.0 for the iMics1 NY-60 IOL and 1.9 ± 1.4 for the AcrySof SN60WF IOL (P < .001). Three years after surgery, 35.6% of patients underwent a neodymium:yttrium-aluminum-garnet capsulotomy in the iMics1 NY-60 eye and 13.7% underwent a capsulotomy in the AcrySof SN60WF eye (P = .001). There was no statistically significant difference in best-corrected visual acuity, rhexis-IOL overlap, capsular folds, or anterior capsule opacification. Glistening formations were found in no iMics1 NY-60 IOLs, but in 97% of the AcrySof SN60WF IOLs.

CONCLUSIONS

Comparison of 2 sharp-edged single-piece IOLs of similar design and hydrophobic acrylic material indicated a statistically significant difference in PCO and neodymium:yttrium-aluminum-garnet capsulotomy rate 3 years after surgery.

[Pseudoexfoliation syndrome and cataract surgery. Avoidance and treatment of complications]

Eyes with pseudoexfoliation syndrome often exhibit insufficient mydriasis, zonular weakness and pronounced fibrotic capsular shrinkage. This may make cataract surgery as such difficult but also leads to postoperative complications, such as rhexis ovalization or phimosis (capsule contraction syndrome) or progressive zonular weakening with final spontaneous dislocation of the capsule-implant complex (CIC). To avoid or correct for this special techniques and implants may be used: as prophylaxis, intracameral adrenalin and retroiridal capsulorhexis, iris retractors or dilators, various models of capsular tension and bending rings, bimanual capsule ring implantation, capsular bag stabilization with iris retractors or segments and secondary capsulorhexis may be used. Rhexis phimosis may be excised by a special diathermic probe, a subluxated CIC may be sutured to the sclera either in toto or the lens only after removal from the capsule bag, the latter also to the posterior iris surface. When luxated into the vitreous cavity, the CIC may be lifted to the iris plane and refixed as described or exchanged for a new lens sutured into the sulcus or an angle or iris-supported anterior chamber lens.