Internal spherical aberration by ray tracing-type aberrometry in multifocal pseudophakic eyes

Spherical aberrations and their role in modern ophthalmology

Spherical aberration is an imperfection of the optical system of the human eye. The role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation is reviewed. Spherical aberration is an imperfection of the optical system of the human eye. In most cases, due to well-developed neuroadaptation, it is insignificant for the perception of the image. Nevertheless, its role in modern ophthalmology is far from straightforward. On the one hand, there are clinical scenarios in which an excess of spherical aberration degrades the retinal image and leads to a high dissatisfaction rate among patients.©Recently, there is a growing interest in the modulation of spherical aberration in the clinical setting. Modern intraocular lenses as well as laser refractive procedures are aimed at interfering with spherical aberrations of the optical system in order to increase range of pseudoaccommodation. Here, we review the role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation.

How Reliable Is Pyramidal Wavefront-Based Sensor Aberrometry in Measuring the In Vivo Optical Behaviour of Multifocal IOLs?

Cataract or refractive lens surgery, along with the implantation of multifocal intraocular lenses (MF-IOL), enables a complete range of functional far, near and intermediate vision. Refractive, diffractive and extended depth of focus (EDoF) or combination of these principles represent the technology used to obtain this multifocality. Aberrometry makes it possible to study the aberrations induced by MF-IOLs. Among the different optical principles available to measure ocular aberrations, pyramidal wavefront-based sensor (PWS) aberrometry shows the highest resolution with MF-IOLs. Retinal image quality measured by a PWS aberrometer differed significantly according to the technology of the implanted lens. Monofocal and diffractive lenses showed the highest values of far-distance retinal image quality, followed by refractive and EDoF lenses; however, retinal image quality analysed in diffractive lenses appears to be more dependent on residual refractive error. Considering this limitation, PWS-aberrometry could be used to compare diffractive lenses. Nevertheless, further studies are needed to provide additional information about the clinical retinal image quality of MF-IOLs and to help surgeons in the important preoperative selection of IOLs.

Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification Surgery: Clinical Outcomes with EDOF IOLs

In this study, we evaluate and compare the outcomes of conventional phacoemulsification cataract surgery (CPS) and femtosecond laser-assisted cataract surgery (FLACS) with the implantation of an extended depth of field (EDOF) intraocular lens (IOL). A prospective, consecutive cohort study was conducted. Patients were given the option to choose FLACS or CPS and were implanted with an EDOF IOL. Refractive data, visual acuity data, ocular aberration measured with a wavefront aberrometer, and optical quality measured with an optical quality analysis system II were collected at one month postoperatively. A total of 92 eyes of 64 patients were enrolled in this study; 35 eyes of 26 patients were treated with FLACS, whereas 57 eyes of 38 patients were treated with CPS. Uncorrected visual acuity at far, intermediate, and near distance and best-spectacle-corrected visual acuity were not statistically significantly different between the groups (all p > 0.05), nor were the mean cylinder and mean spherical equivalent refraction (both p > 0.05). The FLACS group had a lower ocular trefoil than the CPS group (p = 0.033), and there was no significant difference between the two groups considering other aberration parameters, whether ocular or internal (all p > 0.05). Optical-quality-related parameters showed also no significant difference between the two groups (all p > 0.05). In conclusion, there was no significant difference between FLACS and CPS with implantation of EDOF IOLs in postoperative ocular parameters, refractive outcomes, ocular aberration, optical quality, and aberration parameters, except a lower ocular trefoil in the FLACS group. In terms of these indicators, FLACS does not provide an additional clinical benefit for patients over CPS.

Comparison of visual performance between two aspheric monofocal intraocular lens models

CLINICAL RELEVANCE

It is important to distinguish between visual acuity, optical quality and quality of vision when outcomes obtained with intraocular lenses are evaluated. These parameters, that includeobjective and subjective tests, should be assessed to obtain results that are not biased.

BACKGROUND

To assess the difference in visual and optical quality between two monofocal intraocular lens models.

METHODS

: This was a prospective, parallel and randomised clinical study conducted at Miranza IOA, a private clinic in Madrid, Spain. Sixty patients were implanted bilaterally, 30 per group, with two aspheric IOLs with induced spherical aberration of -0.27 μm for Group A and -0.20 μm for Group B. Visual outcomes obtained at 1 and 3 months after surgery included both uncorrected (UCVA) and corrected monocular distance visual acuity (DCVA), objective scattering index (OSI), modulation transfer function (MTF) cut-off, Strehl Ratio (SR), contrast sensitivity defocus curve (CSDC), intraocular lens spherical aberration (SA), and longitudinal chromatic aberration of the eye. Activity limitations in daily life were assessed using CatQuest-9SF questionnaire.

RESULTS

There were statistically significant differences for DCVA (0.04 LogMAR; p = .008) and SR (0.03; p = .003) between groups. Outcomes related to CSDC showed statistically significant differences for vergences between -0.50 D and +1.00 D (3 mm pupil) and for vergences of 0.00 D and +0.50 D (4.5 mm pupil) between groups. Overall, Group A showed better results regarding visual and optical quality, including a lower longitudinal chromatic aberration result in comparison to Group B. Patient satisfaction evaluated with CatQuest-9SF showed that Group A achieved better outcomes, although the differences were statistically significant only for the 'Reading text on television' item (p = 0.027).

CONCLUSIONS

Both intraocular lens models showed excellent quantity of vision, optical and visual quality as well as high patient satisfaction. Despite this, the the Group A model provided slightly better outcomes than the Group B model.

The relationship between patient satisfaction and visual and optical outcome after bilateral implantation of an extended depth of focus multifocal intraocular lens

Purpose

To evaluate patient satisfaction after implantation of the Tecnis Symfony multifocal intraocular lens (MIOL).

Methods

120 eyes of 60 subjects with senile cataract were bilaterally implanted with the Tecnis Symfony IOL. Follow-up examination was performed 6 months postoperatively. Main outcome measures included uncorrected and corrected distance and near visual acuity, manifest refraction, and visual quality metrics. According to their subjective symptoms patient were divided in two groups: satisfied and unsatisfied.

Results

Uncorrected intermediate (0.15 ​± ​0.11 vs 0.18 ​± ​0.01, P ​= ​0.04) and near (0.26 ​± ​0.12 vs 0.31 ​± ​0.11, P ​= ​0.04) (UIVA, UNVA) log MAR visual acuity was significantly better, cylindrical error less (0.31 ​± ​0.36 vs 0.67 ​± ​0.29, P ​= ​0.05), axial length (AL) smaller (23.68 ​± ​1.3 vs 24.22 ​± ​1.6, P ​= ​0.05), Strehl ratio higher (0.08 ​± ​0.08 vs 0.05 ​± ​0.04, P ​= ​0.03) and mesopic pupil larger (4.3 ​± ​1.1 vs 3.7 ​± ​1.05, P ​= ​0.01) among satisfied patients.Residual cylinder, Strehl ratio, halos, mesopic pupil diameter and UNVA were significant predictors of patient satisfaction. Uncorrected distance visual acuity, higher order Strehl ratio and pupil diameter were significant predictors of halos. Near visual acuity significantly correlated (P ​= ​0.018, R ​= ​0.22) with axial length.

Conclusions

Uncorrected cylindrical error, poor reading quality, larger pupil and halos seem to be the most disturbing factors for patients implanted with the Tecnis Symfony IOL.

The impact of visual axis position on the optical quality after implantation of multifocal intraocular lenses with different asphericity values

PURPOSE

To evaluate the effect of visual axis positioning on the optical performance of the Tecnis MIOL and the Diff-aA MIOL.

METHODS

In this prospective, randomized comparative study, 70 eyes of 35 subjects with senile cataract were implanted with the spherical aberration-correcting diffractive, bifocal Tecnis ZLB00 IOL and 60 eyes of 30 age-matched subjects with the spherical aberration neutral, diffractive, bifocal Diffractiva IOL. Observation procedure was performed 1, 3, and 6 months postoperatively. Main outcome measures included uncorrected and corrected distance and near visual acuity, manifest refraction, ocular aberrations, and visual quality metrics with 2 mm and 4 mm pupil and the position of visual axis.

RESULTS

At the 6-month visit, no significant difference was found in monocular and binocular uncorrected (UDVA) and corrected (CDVA) distance and near (UNVA, CNVA) visual acuity between the groups. Spherical and coma-like aberrations were similar measured with a 2-mm pupil, but with a 4-mm pupil, the SA was significantly larger (in negative direction) in the Diffractiva group. The higher-order Strehl ratio and MTF was significantly larger in the Diffractiva group measured at 2 mm entrance pupil; however, this difference disappeared by the 4-mm pupil measurements. Postoperative angle alpha distance had a significant influence on HO Strehl value.

CONCLUSIONS

The size of angle alpha is a predictive factor of image quality by multifocal IOL patients.

TRIAL REGISTRATION

Trial registration number and date of registration: NCT04274088, 14.02.2020.

Effects of Preservative-free 3% Diquafosol in Patients with Pre-existing Dry Eye Disease after Cataract Surgery: A Randomized Clinical Trial

Dry eye disease (DED) after cataract surgery has become a critical concern, and various therapeutic options have been developed. Recently, preservative-free diquafosol ophthalmic solution has been introduced; however, its therapeutic effect on DED after cataract surgery has not been reported. We investigated the efficacy of preservative-free diquafosol in patients with pre-existing DED after cataract surgery. We divided subjects who were diagnosed with DED and scheduled to undergo cataract surgery, into 3 groups (preservative-free diquafosol, group 1; preservative-containing diquafosol, group 2; preservative-free hyaluronate, group 3), and each eye drops was administered 6 times daily after surgery. Tear break up time (TBUT), Ocular Surface Disease Index (OSDI), corneal staining score, lid margin abnormality, and meibum quality improved over time in group 1. Groups 1 and 2 had significantly superior TBUT, meibomian gland dysfunction grade, and meibomian gland expressibility throughout the study period than group 3. Meibum quality of group 1 was significantly better than group 2 at 1 and 3 months after surgery. Preservative-free diquafosol showed better efficacy in treating DED after cataract surgery than preservative-containing diquafosol or preservative-free hyaluronate. Preservative-free diquafosol may serve as a reliable option for the management of patients with pre-existing DED after phacoemulsification.

Effects of Preservative-free 3% Diquafosol in Patients with Pre-existing Dry Eye Disease after Cataract Surgery: A Randomized Clinical Trial

Dry eye disease (DED) after cataract surgery has become a critical concern, and various therapeutic options have been developed. Recently, preservative-free diquafosol ophthalmic solution has been introduced; however, its therapeutic effect on DED after cataract surgery has not been reported. We investigated the efficacy of preservative-free diquafosol in patients with pre-existing DED after cataract surgery. We divided subjects who were diagnosed with DED and scheduled to undergo cataract surgery, into 3 groups (preservative-free diquafosol, group 1; preservative-containing diquafosol, group 2; preservative-free hyaluronate, group 3), and each eye drops was administered 6 times daily after surgery. Tear break up time (TBUT), Ocular Surface Disease Index (OSDI), corneal staining score, lid margin abnormality, and meibum quality improved over time in group 1. Groups 1 and 2 had significantly superior TBUT, meibomian gland dysfunction grade, and meibomian gland expressibility throughout the study period than group 3. Meibum quality of group 1 was significantly better than group 2 at 1 and 3 months after surgery. Preservative-free diquafosol showed better efficacy in treating DED after cataract surgery than preservative-containing diquafosol or preservative-free hyaluronate. Preservative-free diquafosol may serve as a reliable option for the management of patients with pre-existing DED after phacoemulsification.

Effects of Lipid- Versus Sodium Hyaluronate-Containing Eye Drops on Optical Quality and Ocular Surface Parameters as a Function of the Meibomian Gland Dropout Rate

PURPOSE

To evaluate the effect of lipid- versus sodium hyaluronate-based eye drops on optical quality and ocular surface parameters.

METHODS

Sixty eyes of 30 patients with mild-to-moderate dry eye disease were included in a prospective randomized study. Each patient received either lipid- or sodium hyaluronate-based eye drops. Ocular symptom scores, breakup time, Schirmer test, fluorescein staining, noncontact meibography, and aberrometry were evaluated before and after 3 months of therapy.

RESULTS

At the 3-month visit, a statistically significant improvement (P ≤ 0.05) was noted in both groups on the Schirmer test, breakup time, ocular surface staining, and symptom score. In the lipid group, patients with progressive meibomian gland (MG) loss (>50%) showed a significantly greater increase in their corneal higher-order (HO) Strehl ratio (0.25 ± 0.26 vs. -0.01 ± 0.25, P = 0.02) and modulation transfer function (MTF) (0.12 ± 0.17 vs. -0.02 ± 0.06, P = 0.03) than patients with less advanced MG disease. In the lipid group, a significant positive correlation was noted between the MG dropout rate and improvement in Schirmer values [Spearman correlation coefficient (CC): 0.79], corneal HO Strehl (CC: 0.75), and HO modulation transfer function (CC: 0.6), but a significant negative correlation was noted between the MG dropout rate and the HO root mean square (CC: -0.73).

CONCLUSIONS

Lipid-containing artificial tears seem to be superior to sodium hyaluronate-containing drops in terms of improving HO aberrations and optical quality in patients with significant MG dysfunction.

Comparison of the Visual Performance After Implantation of Bifocal and Trifocal Intraocular Lenses Having an Identical Platform

PURPOSE

To compare the visual performance after bilateral implantation of a diffractive bifocal or trifocal intraocular lens (IOL) from the same manufacturer using the same IOL platform.

METHODS

This prospective, non-randomized, controlled study involved patients who had cataract surgery with bilateral implantation of bifocal or trifocal IOLs. The near, intermediate, and distance visual acuities, defocus curve, optical quality including modulation transfer functions and higher-order aberrations, National Eye Institute Visual Functioning Questionnaire-14, patient satisfaction, spectacle independence, and perception of visual disturbances were assessed in all patients.

RESULTS

Fifty eyes (25 patients) were implanted with a diffractive trifocal IOL (AT LISA tri 839MP; Carl Zeiss Meditec, Jena, Germany) and 60 eyes (30 patients) with a diffractive bifocal IOL (AT LISA 809M; Carl Zeiss Meditec). The follow-up was 3 months. No statistically significant difference was found in distance or near visual acuity between the two groups (P ≥ .05). Uncorrected, corrected, and distance-corrected intermediate visual acuities were significantly better in the trifocal IOL group (P < .01). In the binocular defocus curve, the visual acuity was also significantly better for defocus of -1.00 to -2.00 diopters in eyes with trifocal IOL implantation (P < .01). Similar halos and glare were present in the two groups. The levels of overall satisfaction were similarly high between groups.

CONCLUSIONS

Diffractive trifocal IOLs can provide significantly better intermediate vision and equivalent distance and near visual performance compared to bifocal IOLs and do not induce extra qualitative vision disturbances. [J Refract Surg. 2018;34(4):273-280.].

Evaluation of Optical Quality: Ocular Scattering and Aberrations in Eyes Implanted with Diffractive Multifocal or Monofocal Intraocular Lenses

PURPOSE

To compare objective optical quality, ocular scattering and aberrations of eyes implanted with an aspheric monofocal intraocular lens (IOL) or an aspheric apodized diffractive multifocal IOL three months after surgery.

METHODS

Prospective consecutive nonrandomized comparative cohort study. A total of 80 eyes from 57 cataract patients were bilaterally or unilaterally implanted with monofocal (AcrySof IQ SN60WF) or multifocal (AcrySof IQ ReSTOR SN6AD1) IOLs. Respectively, 40 eyes of 27 patients were implanted with monofocal IOLs, and 40 eyes of 30 patients were implanted with multifocal IOLs. Ocular high-order aberration (HOA) values were obtained using Hartmann-Shack aberrometer; objective scatter index (OSI), modulation transfer function (MTF) cutoff, Strehl ratio (SR), and contrast visual acuity OV at 100%, 20%, and 9% were measured using Objective Quality Analysis System II (OQAS II).

RESULTS

Ocular aberrations performed similar in both groups (p > 0.05). However, significantly higher values of OSI and lower values of MTF cutoff, SR and OV were found in the SN6AD1 group (p < 0.05).

CONCLUSIONS

Both ocular scattering and wave-front aberrations play essential role in retinal image quality, which may be overestimated when only aberrations were taken into account. Combining the effect of ocular scattering with HOA will result in a more accurate assessment of the visual and optical quality.

Comparison of Two Toric IOLs with Different Haptic Design: Optical Quality after 1 Year

Background

The purpose of this prospective, randomised study was to interocularly compare the visual performance after implantation of two different toric IOLs with different haptic design.

Methods

59 subjects with corneal astigmatism greater than 1.25 diopter (D) were implanted with an AT TORBI 709M IOL (Carl Zeiss Meditec AG) in one eye and with a Tecnis toric aspheric IOL (Abbot Medical Optics) in the other eye. Observation procedure was performed 12 months postoperatively. Main outcome measures included uncorrected distance visual acuity (UDVA), manifest refraction, IOL rotation, and IOL position.

Results

Mean UCDVA was 0.04 ± 0.14 logMAR for AT TORBI eyes and 0.06 ± 0.15 logMAR for Tecnis eyes (p = 0.3). The postoperative spherical equivalent values were significantly lower in the AT TORBI group. Mean toric IOL axis rotation was 3.0 ± 2.26 degrees for AT TORBI eyes and 3.27 ± 2.37 for Tecnis eyes (p = 0.5). The mean vertical IOL tilt and vertical decentration values measured with the Visante OCT were significantly larger in the AT TORBI group (p < 0.05).

Conclusions

Both the Tecnis and the AT TORBI toric IOLs successfully reduced ocular astigmatism. Emmetropia could be better achieved with the AT TORBI IOL, whereas the Tecnis showed better positional stability. This trial is registered with ICMJE NCT03371576.

The efficiency of aspheric intraocular lens according to biometric measurements

Purpose

To analyze internal spherical aberration in pseudophakic eyes that underwent aspheric intraocular lens (IOL) implantation, and to investigate the relationships between biometric data and the effectiveness of aspheric IOL implantation.

Methods

This retrospective study included 40 eyes of 40 patients who underwent implantation of an IOL having a negative spherical aberration of -0.20 μm (CT ASPHINA 509M; Carl Zeiss Meditec Inc., Germany). The IOLMaster (version 5.0; Carl Zeiss AG, Germany) was used for preoperative biometric measurements (axial length, anterior chamber depth, central corneal power) and the measurement of postoperative anterior chamber depth. The spherical aberrations were measured preoperatively and 3 months postoperatively using the iTrace (Tracey Technologies, Houston, TX, USA) at a pupil diameter of 5.0 mm. We investigated the relationships between preoperative biometric data and postoperative internal spherical aberration, and compared biometric measurements between 2 subgroups stratified according to internal spherical aberration (spherical aberration ≤ -0.06 μm vs. spherical aberration > -0.06 μm).

Results

The mean postoperative internal spherical aberration was -0.087 ± 0.063 μm. Preoperative axial length and residual total spherical aberration showed statistically significant correlations with internal spherical aberration (p = 0.041, 0.002). Preoperative axial length, postoperative anterior chamber depth, IOL power, and residual spherical aberration showed significant differences between the 2 subgroups stratified according to internal spherical aberration (p = 0.020, 0.029, 0.048, 0.041 respectively).

Conclusion

The corrective effect of an aspheric IOL is influenced by preoperative axial length and postoperative anterior chamber depth. Not only the amount of negative spherical aberration on the IOL surface but also the preoperative axial length should be considered to optimize spherical aberration after aspheric IOL implantation.

A comparative study of the visual outcomes between a new trifocal and an extended depth of focus intraocular lens

PURPOSE

To evaluate and compare the visual outcomes and ocular optical performance of the PanOptix trifocal intraocular lens (IOL) and Symfony extended range of vision IOL.

METHODS

Sixty-eight eyes of 34 patients were divided into 2 groups: 20 patients with the PanOptix IOL and 14 patients with the Symfony IOL. Binocular uncorrected distance visual acuity, best-corrected distance visual acuity (BCDVA), distance-corrected intermediate visual acuity (DCIVA) at 80 and 60 cm, and distance-corrected near visual acuity (DCNVA) at 40 cm were evaluated. Additionally, preferred reading distance with best-corrected distance and visual acuity at that distance, binocular defocus curves, mesopic and photopic contrast sensitivity, photic phenomena, and monocular total higher order aberrations (HOAs) were also measured.

RESULTS

The visual outcomes for PanOptix and Symfony IOL groups, respectively, were as follows: BCDVA: -0.03 ± 0.03 and -0.02 ± 0.03 logMAR; DCIVA at 80 cm: 0.06 ± 0.06 and 0.06 ± 0.04 logMAR; DCIVA at 60 cm: 0.06 ± 0.10 and 0.05 ± 0.04 logMAR; DCNVA: 0.04 ± 0.06 and 0.20 ± 0.07 logMAR (p<0.001). Similar preferred reading distances were found for both groups (37.0 ± 4.6 and 38.9 ± 5.7 cm, respectively). The visual acuities at those distances were 0.09 ± 0.08 and 0.19 ± 0.08 logMAR (p<0.001), respectively. The defocus curves showed significantly better outcomes for the PanOptix IOL from -2.0 to -4.0 D (p<0.001). No significant differences were found for contrast sensitivity, halometry, or HOAs between the groups.

CONCLUSIONS

The PanOptix and Symfony IOLs showed comparable visual performance at distance and intermediate. However, the PanOptix IOL provided better near and preferred reading distance VAs and showed a more continuous range of vision than the Symfony IOL.

Comparison of the Orbscan II topographer and the iTrace aberrometer for the measurements of keratometry and corneal diameter in myopic patients

Background

The purpose of this study was to compare corneal power and horizontal corneal diameter (white-to-white [WTW] distance) readings obtained by the Orbscan II topographer and the iTrace aberrometer.

Methods

Keratometry readings in the flat (Kf) and steep (Ks) meridians and WTW distance were measured with the Orbscan II and iTrace systems in 100 myopic patients. Statistical evaluation was performed using the paired t test, Pearson correlation, and Bland-Altman analysis for comparison of measurement techniques.

Results

The mean keratometry values with the Orbscan II and iTrace were 43.16 ± 1.44 and 42.64 ± 1.43 diopter (D), respectively (P < 0.0001). The mean WTW distance measurements with the Orbscan II and iTrace were 11.57 ± 0.34 and 11.33 ± 0.36 mm, respectively (P < 0.0001). For the measurement of corneal power, the 95 % limits of agreement (LoA) between the Orbscan II and iTrace were − 0.21 to 1.21 D for the flat meridian and − 0.15 to 1.25 D for the steep meridian. For the measurement of WTW distance, the range of the 95 % LoA between the two devices was 0.47 mm.

Conclusions

For some clinical applications, the keratometry and WTW distance measurements obtained by the Orbscan II topographer and the iTrace aberrometer differed greatly and therefore were not interchangeable.

Trial registration

Clinical trials number: ChiCTR-OCS-14005077 (August 2nd, 2014).

Clinical Outcomes Following Implantation of Diffractive Multifocal Intraocular Lenses With Varying Add Powers

PURPOSE

To compare clinical outcomes after implantation of TECNIS diffractive multifocal intraocular lenses (IOLs) with different add powers.

DESIGN

Prospective, comparative, interventional case series.

METHODS

Subjects underwent cataract extraction and diffractive multifocal IOL implant. Subjects had an additional add power of +2.75 diopters (D) (Group 1, 23 eyes), +3.25 D (Group 2, 21 eyes), or +4.00 D (Group 3, 21 eyes). Evaluations were performed 1 and 3 months following cataract surgery, including measurement of monocular uncorrected distance visual acuity (UDVA), refractive error (manifest refraction [MR]), and monocular uncorrected near visual acuity (UNVA) at 33, 40, and 50 cm. At 3 months, internal aberrations and contrast sensitivity were evaluated and subjects completed a questionnaire on outcomes satisfaction, visual symptoms, and spectacle use.

RESULTS

Sixty-five eyes (43 subjects) were included. After surgery, no significant differences between groups were observed in UDVA and MR values. UNVA at 33 cm was best in Group 3 (1 month: P = .032; 3 months: P = .031). Three months after surgery, UNVA was best in Group 1 at 50 cm (P = .017). No significant differences in internal aberration and contrast sensitivity were observed between groups and surgical satisfaction was worst in Group 3 (P = .001). A total of 87.0%, 85.7%, and 76.9% had spectacle independence in Groups 1, 2, and 3, respectively (P = .080).

CONCLUSIONS

TECNIS diffractive multifocal IOLs with lower add powers provide good vision over longer working distances and excellent distant vision. Subjects with lower add power had greater satisfaction, more spectacle independence, and fewer visual symptoms than those with +4.00 D add.

OCULAR WAVEFRONT ABERRATIONS AND OPTICAL QUALITY IN DIABETIC MACULAR EDEMA

PURPOSE

To evaluate optical quality and internal aberrations in patients with diabetic macular edema.

METHODS

In this prospective study, 33 eyes of patients with diabetic macular edema were scanned with a ray-tracing wavefront device. As a control group, wavefront aberrometry was performed in 31 patients. Ocular and internal aberrations and visual quality metrics were evaluated separately to determine whether the source of aberrations was ocular or internal. Main outcome measures included corrected visual acuities, ocular and internal aberrations, Strehl ratio, and modulation transfer function.

RESULTS

There was a statistically significant difference between the groups in internal higher order (HO) root mean square (0.34 ± 0.24 vs. 0.16 ± 0.05), HO Strehl ratio (0.08 ± 0.05 vs. 0.18 ± 0.09), and modulation transfer function (0.29 ± 0.1 vs. 0.4 ± 0.1). There was no statistically significant difference in Strehl ratio and HO root mean square between phakic and pseudophakic patients. Height of cystoid spaces was a significant predictor (P < 0.001) of Strehl ratio. Besides inner and outer segment integrity, HO Strehl ratio significantly determined best-corrected visual acuity.

CONCLUSION

In eyes with macular edema, internal HO wavefront aberrations were greater than in control eyes. This increase in HO wavefront error seems visually relevant. This study results suggest increased intraretinal edema as the source of HO aberrations.

Evaluation of optical quality parameters and ocular aberrations in multifocal intraocular lens implanted eyes

PURPOSE

We investigated the correlations between optical quality parameters obtained from the double-pass system and ocular aberrations obtained from the ray-tracing aberrometer in multifocal intraocular lens (IOL) implanted eyes.

MATERIALS AND METHODS

Twenty eyes from 20 patients were enrolled in this study. Modulation transfer function cutoff frequency, The Strehl ratio, objective scatter index, and objective pseudo-accommodation obtained from the double-pass system were compared with root mean square (RMS) total aberration, RMS higher-order aberration, and spherical aberration obtained from the ray-tracing aberrometer. Additionally, parameters of the double-pass system and ray-tracing aberrometer were compared with manifested refraction values and subjective visual acuity, respectively.

RESULTS

There was no statistically significant correlation between optical quality parameters obtained from the double-pass system and ocular aberrations, except between the Strehl ratio and RMS total aberration (r=-0.566, p=0.018). No significant correlations were found between the parameters of both devices, and manifested refraction values or subjective visual acuity.

CONCLUSION

Optical quality parameters, especially the Strehl ratio, in multifocal IOL implanted eyes were affected by RMS total aberration. Further studies based on accurate measurements of ocular aberrations and additional optical quality parameters are needed to delineate relationships between optical quality parameters and ocular aberrations in multifocal IOL implanted eyes.