Changes of Corneal Higher-Order Aberrations after Cataract Surgery

The impact of corneal higher-order aberrations on dynamic visual acuity post cataract surgery

Purpose

To explore the influence of corneal higher-order aberrations (HOAs) on dynamic visual acuity (DVA) post cataract surgery.

Methods

A total of 27 patients with 45 eyes following cataract surgery were included in this study. The postoperative monocular object-moving DVA at the velocity of 20, 40, and 80 degrees per second (dps) were examined at 1 month. The total corneal HOAs were measured with Scheimpflug-based corneal topography. The correlation between postoperative DVA and HOAs was analyzed.

Results

Significant difference was shown among DVA at different velocities (P < 0.001). The 20 dps DVA was significantly better than 40 (P < 0.001) and 80 (P < 0.001) dps DVA. No significant difference was observed between 40 and 80 dps DVA (P = 0.420). The vertical coma and the root mean square (RMS) of coma (RMScoma) were statistically correlated with 80 dps DVA (P < 0.05). The vertical trefoil, RMStrefoil and total RMSHOA were statistically correlated with 40 and 80 dps DVA (P < 0.05). The spherical aberration was not significantly associated with postoperative DVA (P > 0.05 for all velocites). The multivariate linear regression model revealed that age was a significant influential factor for 20 dps DVA (P = 0.002), and RMStrefoil (4 mm) and age were significantly associated with 40 and 80 dps DVA (P ≤ 0.01).

Conclusion

The research demonstrated that larger corneal HOAs, especially coma and trefoil aberrations were significantly associated with worse high-speed DVA, but not spherical aberration post cataract surgery.

Risk Factors for Corneal Monochromatic Aberrations and Implications for Multifocal and Extended Depth-of-Focus Intraocular Lens Implantation

PURPOSE

To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation.

METHODS

PubMed and Scopus were the main resources used to search the medical literature. An extensive search was performed to identify relevant articles concerning factors influencing the level of corneal aberrations as of August 27, 2023. The following keywords were used in various combinations: corneal, aberrations, defocus, astigmatism, spherical aberration, coma, trefoil, quadrafoil, intraocular lens, and IOL.

RESULTS

Conclusive evidence is lacking regarding the correlation between age and changes in corneal aberrations. Patients with astigmatism have greater corneal higher-order aberrations than those with minimal astigmatism, particularly concerning trefoil and coma. Increased levels of corneal higher-order aberrations are noted following contact lens wear, in patients with dry eye disease, and with pterygium. Increased higher-order aberrations have been reported following corneal refractive surgery and for 3 months following trabeculectomy; regarding intraocular lens surgery, the results remain controversial.

CONCLUSIONS

Several factors influence the level of corneal higher-order aberrations. Multifocal and extended depth-of-focus IOLs can share similarities in their optical properties, and the main difference arises in their design and performance with respect to spherical aberration. Preoperative evaluation is critical for proper IOL choice, particularly in corneas with risk of high levels of aberrations. [J Refract Surg. 2024;40(6):e420-e434.].

Changes in Corneal Higher-Order Aberrations and Ocular Biometric Measurements after Phacoemulsification Combined with Goniosynechialysis in Primary Angle Closure/Glaucoma Patients

Purpose

To compare corneal higher-order aberrations (HOAs), refractive error, and ocular biological parameters before and after phacoemulsification combined with goniosynechialysis (Phaco-GSL) in primary angle closure/glaucoma (PAC/PACG) patients with different axial lengths (ALs).

Methods

In this prospective study, cataract patients diagnosed with PAC/PACG were categorized into two groups based on their ALs: the short AL group (AL ≤ 22.5 mm) and the normal AL group (22.5 < AL ≤ 24.5 mm). The pre- and postsurgery measurements of intraocular pressure (IOP) and best-corrected visual acuity (BCVA) were conducted at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months. Additionally, the assessments included corneal HOAs, the number of antiglaucoma medications, visual field parameters, manifest refraction, and other ocular biological parameters before surgery and at the final follow-up.

Results

Prior to surgery, the two groups exhibited no significant differences, except for AL, curvature value, and Z (4, 0) of the posterior corneal surface (all P < 0.01). Following surgery, BCVA improved, and IOP decreased significantly in both groups (P < 0.01). Both anterior and total corneal HOAs, along with Z (3, -3), increased in the two groups (all P < 0.05), with the normal AL group exhibiting a significantly greater increase in total cornea Z (3, -3) than the short AL group (P=0.047). The normal AL group also exhibited a slight tendency towards hyperopia (P < 0.01). Significant changes were observed in the visual field index and mean deviation in both groups (P < 0.05).

Conclusions

Phaco-GSL resulted in an increased corneal HOAs, particularly trefoil, with variations based on the patient's AL. Patients with normal ALs tended to shift towards hyperopia after surgery.

Changes in Corneal High Order Aberrations and Anterior Chamber Parameters Following Scleral Fixated Intraocular Lens Implantation

BACKGROUND

To evaluate the change in corneal high order aberrations (HOAs) and anterior chamber parameters following scleral fixation in aphakic patients using the Scheimpflug camera system.

METHODS

This retrospective study included patients who were aphakic after phacoemulsification surgery and underwent scleral-fixed intraocular lens (SF-IOL) implantation with Z suture technique between 2010 and 2022. Preoperative and postoperative best corrected visual acuity (BCVA), anterior segment parameters and corneal aberrations were evaluated with a combined Scheimpflug-Placido disc corneal topography device (Sirius Costruzione Strumenti Oftalmici, Florence, Italy). The following values were recorded: Simulated keratometry (SimK), flat meridian (K1), steep meridian (K2), iridocorneal angle (ICA), temporal anterior chamber angle (T-ACA), nasal anterior chamber angle (N-ACA), horizontal anterior chamber diameter (HACD), anterior chamber volume (ACV), corneal volume (CV), total Root Mean Square (RMS), high order aberrations (HOAs), spherical aberration, coma, trefoil, quadrifoil, and secondary astigmatism.

RESULTS

The study included 31 eyes of 31 patients (mean age: 63.00±19.41 years, 17 males/14 females). Postoperative BCVA was better than preoperative BCVA (p=0.012). Postoperatively, there was a statistically significant increase in ACV and CV values and a statistically significant decrease in K2 (p=0.009, p=0.032, p=0.015). Preoperative T-ACA and preoperative and postoperative ACV were negatively correlated with postoperative intraocular pressure (r=-0.427 p=0.033, r=-0.406 p=0.032 and r=-0.561 p=0.001). There were statistically significant postoperative increases in corneal RMS, trefoil and HOAs for 3 mm pupil diameter (p=0.0177, p=0.001, p=0.031) and in corneal RMS, trefoil and quadrifoil aberrations for 6 mm pupil diameter (p=0.033, p=0.001, p=0.001).

CONCLUSIONS

In conclusion, SF-IOL implantation with Z-suture technique used for visual rehabilitation of aphakic patients may affect visual quality by increasing corneal HOAs while improving visual acuity.

Change Patterns in Corneal Intrinsic Aberrations and Nerve Density after Cataract Surgery in Patients with Dry Eye Disease

This study aimed to evaluate the change patterns in corneal intrinsic aberrations and nerve density after cataract surgery in dry eye disease. The preoperative, 1- and 3-month postoperative dry eye-related parameters were obtained by the Oculus keratograph and the ocular surface disease index questionnaire. The corneal intrinsic aberrations were measured using the Pentacam HR system. In vivo confocal microscopy was performed to observe the vortical and peripheral corneal nerves. An artificial intelligence technique run by the deep learning model generated the corneal nerve parameters. Corneal aberrations on the anterior and total corneal surfaces were significantly increased at 1 month compared with the baseline (p < 0.05) but gradually returned to the baseline by 3 months (p > 0.05). However, the change in posterior corneal aberration lasted up to 3 months (p < 0.05). There was a significant decrease in the corneal vortical nerve maximum length and average density after the operation (p < 0.05), and this damage lasted approximately 3 months. The corneal vortical nerve maximum length and average density were negatively correlated with the anterior corneal surface aberrations before and 1 month after the operation (correlation coefficients, CC = −0.26, −0.25, −0.28; all p < 0.05). Corneal vortex provided a unique site to observe long-term corneal nerve injury related to eye dryness. The continuous damage to the corneal vortical nerve may be due to the continuous dry eye state.

Corneal irregularity and visual function using anterior segment optical coherence tomography in TGFBI corneal dystrophy

The purpose of this study was to evaluate corneal irregular astigmatism of patients with granular and lattice corneal dystrophy (GCD and LCD). 70 GCD, 35 LCD, and 81 control eyes were included. Anterior and posterior corneal topographic data obtained from anterior segment optical coherence tomography were expanded into four components via Fourier harmonic analysis. These components were compared with healthy eyes and the association between each component and best-corrected visual acuity (BCVA) was investigated. Anterior and posterior components increased in both GCD and LCD eyes. Anterior and posterior components of GCD2, anterior of LCD type 1 (LCD1), posterior of LCD type IIIA (LCD 3A), and type IV (LCD4) significantly increased. BCVA was significantly associated with anterior and posterior components in LCD eyes but not in GCD. The anterior components of LCD1, anterior and posterior of LCD3A, and posterior of LCD4 , were positively correlated with BCVA. As conclusions, in GCD eyes, anterior and posterior components differed from those of the control but BCVA was not significantly associated with them. In LCD eyes, the anterior and posterior components increased, and BCVA was significantly associated with the anterior and posterior components.

Influence of Overhanging Bleb on Corneal Higher-Order Aberrations after Trabeculectomy

Recent advances in ocular aberrometry have revealed that ocular surgery increases ocular and corneal higher-order aberrations. This retrospective single-center study aimed to examine the effects of the overhanging bleb on corneal higher-order aberrations using a wavefront analyzer. We included 61 eyes from 50 patients with overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C (overhanging bleb group) and 65 eyes from 54 glaucoma patients with no history of glaucoma surgery (control group). Corneal higher-order aberrations (total higher-order aberrations, coma aberrations, coma-like aberrations, spherical aberrations, and spherical-like aberrations) on a 4 mm pupil diameter were measured using the TOPCON KR-1W wavefront analyzer. Corneal coma aberrations were higher in the overhanging bleb group than in the control group (0.16 ± 0.13 μm and 0.10 ± 0.05 μm, respectively; p = 0.042). Corneal coma-like aberrations were also higher in the overhanging bleb group than in the control group (0.31 ± 0.32 μm and 0.16 ± 0.09 μm, respectively; p = 0.022). With an increasing ratio of cornea covered by the bleb to the entire cornea, all corneal higher-order aberrations increased except for corneal coma-like aberrations. Overhanging bleb after trabeculectomy with a fornix-based conjunctival flap using mitomycin C and its size influenced corneal higher-order aberrations.

Effect of Central Corneal Thickness on Corneal Higher Order Aberrations After Cataract Surgery

PURPOSE

To investigate the changes of corneal higher order aberrations (HOAs) before and after phacoemulsification in patients with different central corneal thickness (CCT).

METHODS

In this retrospective non-randomized, non- comparative cases series, 51 eyes of 51 patients who underwent phacoemulsification were enrolled. The corneal total HOAs and Zernike coefficients (3rd and 4th order) over the 3- and 4-mm zones were measured by the iTrace aberrometer (Tracey Technologies). Participants were divided into three groups (528 µm or less, 529 to 550 µm, and greater than 550 µm) depending on the CCT tested by the LenStar LS900 (Haag Streit AG). The corneal aberrations between groups were compared with analysis of variance, the variation of corneal aberrations before and after phacoemulsification was analyzed by the paired-samples t test, and generalized linear models were used to compare postoperative aberrations between groups.

RESULTS

Significant differences were found in oblique trefoil at 3 mm and vertical trefoil, oblique trefoil, and HOAs at 4 mm in the 528 µm or less group; vertical trefoil, oblique trefoil, oblique quadrafoil, and oblique secondary astigmatism at 3 mm and oblique trefoil and oblique secondary astigmatism at 4 mm in the 529 to 550 µm group; and vertical quadrafoil at 3 mm in the greater than 550 µm group. After corrected deviation of preoperative aberrations, there were significant differences in postoperative vertical coma and oblique secondary astigmatism at 4 mm when compared to the 528 µm or less and greater than 550 µm groups.

CONCLUSIONS

The lower the CCT, the greater the change in corneal aberrations in patients with cataract after phacoemulsification. Surgeons should be aware of the potential for worse visual quality related to surgically induced aberrations in patients with thin corneas. [J Refract Surg. 2021;37(12):842-847.].

Higher Order Aberrations following Scleral Buckling Surgery in Patients with Rhegmatogenous Retinal Detachment

We aim to evaluate magnitudes of higher order aberrations (HOAs) from 3rd–6th order after scleral buckling (SB) for rhegmatogenous retinal detachment (RRD). A retrospective cross-sectional study of 19 patients with RRD who received SB (six receiving encircling SB, thirteen receiving segmental SB) was conducted. A wavefront analysis for surveying HOAs and other ophthalmic parameters were collected. Data between operated and fellow eyes, and a subgroup analysis of operated eyes, were analyzed by the Mann–Whitney U test, while a generalized linear model was applied to evaluate the correlation of HOAs to best-corrected visual acuity (BCVA) and optical symptoms. BCVA in the operated eyes was significantly worse (LogMAR: 0.18 ± 0.23 versus 0.05 ± 0.07, p = 0.001). Tilt (0.32 ± 0.14 versus 0.13 ± 0.08, p = 0.004), defocus (1.78 ± 0.47 versus 1.05 ± 0.17, p = 0.019) and coma (0.43 ± 0.11 versus 0.27 ± 0.09, p = 0.016) were significantly increased after SB. All root mean square (RMS), including RMS-3, RMS-4 and total RMS, were higher in operated eyes (all p < 0.05). Regarding Zernike terms, a significant elevation of vertical coma in the operated eyes was found (p = 0.038). In addition, tilt (0.41 ± 0.10 versus 0.17 ± 0.12, p = 0.007), defocus (2.27 ± 0.58 versus 0.82 ± 0.39, p = 0.001) and coma (0.59 ± 0.17 versus 0.11 ± 0.10, p = 0.015) were higher in the segmental subgroup, whereas spherical aberration (SA) was higher in the encircling subgroup (0.22 ± 0.04 versus 0.40 ± 0.15, p = 0.024) and RMS-4 and total RMS were increased in the segmental subgroup (both p < 0.05). Besides, tilt was correlated to worse BCVA (p = 0.036), whereas all four HOAs were correlated to the presence of optical symptoms (all p < 0.05). In conclusion, SB may increase HOAs, which could be associated with unfavorable postoperative visual outcomes and subject symptoms.

Effect of corneal incision features on anterior and posterior corneal astigmatism and higher-order aberrations after cataract surgery

PURPOSE

To evaluate the influence of 2.2 mm clear corneal incision (CCI) features in surgically induced astigmatism (SIA) and higher-order aberrations (HOAs) after cataract surgery.

METHODS

Right eyes of 92 subjects receiving 2.2 mm incision cataract surgery were involved. A total of 38 eyes were categorized as the intact incision group, and 54 eyes were the defective incision group. Pre- and postoperative (1 month and 6 months) corneal astigmatism and HOAs on anterior and posterior corneal surfaces, corneal volume, and corneal thickness (CT) were measured using Pentacam. The CCI features including incision length (IL), incision angles, distance from incision to central cornea (Dis-En/Ex), and CT at incision site were quantified using AS-OCT.

RESULTS

The defective incision group showed shorter IL and larger incision angles [false discovery rate (FDR) - p < 0.05]. Changes in CT at incision site were more pronounced for the defective incision group (FDR - p < 0.05). Some SIA parameters were related to the certain specific CCI features, especially IL (FDR - p < 0.05). Both groups exhibited significant increased 6 mm posterior corneal tHOAs at 1 month (Bonferroni corrected - p < 0.01) and the defective incision group showed increased 6 mm posterior tHOAs at 6 months (Bonferroni corrected - p = 0.023). There were characteristic correlations between Zernike terms and CCI features including IL, CT, Dis-En/Ex, and incision angles at 1 month, especially over 6 mm zone.

CONCLUSION

The CCI deformities can affect corneal recovery and induce more HOAs at 1 month postoperatively. Such effects became minor, but could persist until 6 months. The IL combined with Angle-En/Ex was important factor influencing CCI integrity and corneal optical quality.

Astigmatism correction with toric implantable collamer lens in low and high astigmatism groups

PURPOSE

To analyze the target induced astigmatism (TIA), surgically induced astigmatism (SIA), difference vector (DV), and correction index (CI) in the correction of astigmatism with phakic lenses, and its influence on visual acuity, and to analyze the safety and efficacy indexes of the correction of high and low power astigmatism with toric phakic lenses.

DESIGN

Retrospective comparative study.

METHODS

The medical records of patients that were operated on at the research center during the period were analyzed. Results were divided into Low Astigmatism Group - LAG (33 eyes) and High Astigmatism Group - HAG (93 eyes) according to the implanted toric ICL lens power. Preoperative refraction and resultant postoperative refraction were analyzed by vector analysis. Visual acuity pre and postop, with and without optical correction, were compared.

RESULTS

A total of 126 eyes were studied. The average preop refraction was -5.02 D sphere with -2.61 D cylinder. The average ICL lens power implanted was -8.31 D sphere +2.77 D cylinder. Refractive remaining was -0.01 ± 0.11 D sphere -0.15 ± 0.28 D cylinder. The arithmetic average angle of error in the astigmatism correction was 1.08°. The resultant cylinder was -0.03 ± 0.12 D and -0.19 ± 0.30 D in the low and high astigmatism groups, respectively, with a mean UDVA -0.01 ± 0.10 and 0.01 ± 0.16 and CDVA -0.03 ± 0.08 and -0.01 ± 0.17 for each group. The safety and efficacy indexes for the low astigmatism group were 1.09 ± 0.16 and 1.05 ± 0.17, respectively, with 1.11 ± 0.17 and 1.06 ± 0.16 for the high astigmatism group.

CONCLUSIONS

The correction of astigmatism by the implantation of toric phakic lenses of the posterior chamber is safe and effective, independently of the amount of cylinder corrected.

Effect of diquafosol three per cent ophthalmic solution on tear film and corneal aberrations after cataract surgery

BACKGROUND

The aim was to evaluate the effect of diquafosol on tear film parameters and corneal aberrations after cataract surgery.

METHODS

This retrospective, comparative, observational case series included patients who underwent cataract surgery with or without peri-operative use of diquafosol three per cent ophthalmic solution. Patients in group I (31 eyes) were treated with diquafosol three per cent ophthalmic solution six times a day from one week before surgery to three months after surgery. Patients in group II (33 eyes) underwent cataract surgery without being administered diquafosol. Tear film break-up time (BUT), the ocular surface disease index (OSDI), the Oxford Scheme score, Schirmer's test I and corneal aberrations were determined before and at one and three months post-surgery.

RESULTS

In group I, the BUT, OSDI and Oxford Scheme score showed significant improvement at one and three months post-surgery (p = 0.002 for BUT at one month and three months, p = 0.023 and p = 0.049 for OSDI at one month and three months and p = 0.001 and p = 0.026 for Oxford Scheme at one month and three months), compared to baseline. In group II, the BUT, OSDI and Oxford Scheme score did not show any significant improvement during the follow-up period. In both groups, Schirmer's test I significantly decreased at three months post-surgery (p = 0.011 for group I and p = 0.034 for group II), compared to baseline. There were significant differences in the BUT and OSDI between the groups at three months post-surgery (p = 0.037 for BUT and p = 0.011 for OSDI). Regarding the corneal aberration, there were no significant differences between the groups at three months post-surgery.

CONCLUSION

Peri-operative application of diquafosol three per cent ophthalmic solution may prevent dry eye-related ocular surface changes accompanied by improvement of ocular symptom. No definite changes in corneal aberrations were noted.

Pseudo-accommodation in non-amblyopic children after bilateral cataract surgery and implantation with a monofocal intraocular lens: prevalence and possible mechanisms

BACKGROUND

Some pseudophakic patients implanted with a monofocal intraocular lens (IOL) have good near visual acuity (VA) with their distance correction. The objective was to evaluate the prevalence of pseudo-accommodation in children after bilateral cataract surgery, without amblyopia, and to define its mechanisms.

METHODS

Observational study that took place in a pediatric ophthalmology department, Paris, France. A total of 68 eyes were included, 40 from 23 children and 28 from 14 adults, with a corrected distance VA above 20/25 and a normal near VA (20/25) with +3 addition. Pseudo-accommodation was defined as a near VA better than 20/50 with the distance correction and without addition. Prevalence of pseudo-accommodation was calculated in each group. In order to determine the possible mechanisms of pseudo-accommodation in children, we compared children with pseudo-accommodation and adults without pseudo-accommodation regarding several parameters: refraction, axial length, corneal topography, aberrometry, pupillary diameter and IOL shift after cyclopentolate instillation.

RESULTS

Among the children group, 36 (90 %) had pseudo-accommodation versus 2 (7 %) in the adult group. We found that spherical equivalent, implant power, corneal multifocality and corneal higher-order aberrations (mainly coma and trefoil) were significantly higher in the pseudo-accommodation group, while pupil diameter and implant shift were not significantly different.

CONCLUSIONS

Pseudo-accommodation has a high prevalence among non-amblyopic pseudophakic children. Several possible mechanisms have been found to explain pseudo-accommodation in children: a high power of the IOL and a small axial length, maximizing the effect of the IOL shift, corneal multifocality and corneal higher-order aberrations.