Navigating the high-speed impact of corneal higher-order aberrations after cataract surgery
A new study sheds light on the intricate relationship between corneal higher-order aberrations and dynamic visual acuity post-cataract surgery. With findings suggesting that specific aberrations can significantly affect vision at higher speeds, this study offers valuable insights for refractive surgeons and their patients.
While lower-order aberrations (LOA) are correctable, higherorder aberrations (HOA) are more challenging to address. LOAs, such as myopia, hyperopia and regular astigmatism, account for nearly 90% of the total aberrations in human eyes and can be corrected with spectacles or contact lenses. 1 On the other hand, HOAs, such as coma and spherical aberrations, cannot be corrected with conventional methods. 2
As patient expectations rise, so does the need to correct HOAs to achieve better outcomes and quality of vision after cataract surgery, especially given increasingly demanding lifestyles and needs.
Correlation between HOAs and DVA velocities
A study titled The impact of Corneal Higher-Order Aberrations on Dynamic Visual Acuity (DVA) on Post-Cataract Surgery explores the influence of corneal HOAs on DVA after cataract surgery.3
A total of 27 patients with 45 eyes following cataract surgery were included in the 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.3
Results showed that there was a significant difference 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 velocities). 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).3
In 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.
“This study resonates deeply with my practice as a refractive surgeon,” commented Dr. Noor Aniah Azmi, medical director and consultant refractive surgeon at the Ikonik Eye Specialist and General Health Centre, Malaysia.
Optimizing patient outcomes post-cataract surgery
In today’s world, patient expectations have evolved beyond merely achieving a 20/20 vision. They seek a level of ‘perfection’ that enhances their comfort and performance in daily activities, added Dr. Noor Aniah
“This research opens the door to more sophisticated post-operative evaluations, allowing us to better understand and address our patient’s ocular issues. It helps me comprehend how these factors impact their daily activities, such as driving at night,” she explained.
The results of the study highlighted the potential challenges that patients with higher levels of these aberrations may face in dynamic situations—such as driving at night— which could profoundly impact their quality of life.
That said, there are limitations. “Ideally, we all want to give our patients the best possible care by addressing HOAs to improve their visual outcomes. However, some practical challenges make this difficult, such as measuring HOAs, which can be complex and often require advanced technology that isn’t available in every practice. Even with the necessary tools, interpreting the results can be tricky,” explained Dr. Noor Aniah.
She added that treatment options for HOAs remain limited and may not be suitable for every patient.
“Hence, while we aim for excellence in patient care, we must also balance the ideal with the realities of clinical practice. It would be interesting to correlate these findings with patientreported outcomes,” she said.
Insights into HOA-related postoperative visual challenges
Assoc. Prof. Dato’ Dr. Khairidzan Mohd Kamal, director of Cornea, External Disease, and Refractive Surgery at the International Islamic University Malaysia (IIUM) Eye Specialist Clinic, said the study may provide insights into postoperative visual challenges—such as those for specific corneal HOAs (coma and trefoil) and reductions of DVA at fast motion speeds (40°/s and 80°/s). It may help in improving patients’ visual quality.
He pointed out that one notable finding of the study was that bigger corneal HOAs, particularly coma and trefoil aberrations, significantly worsen DVA at faster rates following cataract surgery. Age was also a significant factor in DVA, indicating that older patients may have more severe HOA-related visual abnormalities.
According to the study, some aberrations contribute more than others to visual function at high speeds, suggesting that specific therapies may be necessary.
“Collectively, these results highlight how important corneal HOAs and patient age are to visual outcomes following cataract surgery, particularly for tasks requiring dynamic vision,” explained Assoc. Prof. Dato’ Dr. Khairidzan.
“The implications for patients undergoing cataract surgery are multifaceted. Surgeons are more equipped to comprehend postoperative visual complaints from patients, especially those pertaining to motion when they are aware of the influence of corneal HOAs on DVA,” he added.
To maintain adequate visual function, older patients may require additional therapies or closer monitoring, as age is a key factor.
Additionally, patients’ expectations can also be set. “By helping patients understand how corneal HOAs may impact their dynamic vision, postoperative expectations are more realistically set, improving the doctorpatient bond,” he continued.
Moreover, Assoc. Prof. Dato’ Dr. Khairidzan added that this study highlights the need for greater investigation into intraocular lenses (IOLs) and surgical methods that better manage corneal HOAs.
“These ramifications emphasize the importance of considering lifestyle needs alongside physical requirements when organizing procedures,” he said.
Patients who have corneal abnormalities may experience visual disturbances that make it difficult for them to engage in dynamic vision-intensive activities, like driving or sports. They may have a higher quality of life if these anomalies are corrected, he emphasized.
Surgeons can improve postoperative visual results and increase patient satisfaction by carefully selecting appropriate IOLs and possibly correcting HOAs during surgery.
A call for further investigation
Additional research is necessary, Assoc. Prof. Dato’ Dr. Khairidzan explained, for the following reasons: Although corneal HOAs are the main subject of the study, intraocular HOAs are also very important for total visual quality. Future studies that take these into account might offer a more complete picture of postoperative vision.
One drawback of DVA testing is the absence of pupil diameter measurements. Although difficult to do, using this data could improve the precision of results pertaining to HOA profiles.
The limited sample size of the study and the lack of previous, comparable studies raise concerns about statistical bias. More extensive and varied sample sizes will be needed in future research to verify these results and guarantee wider use.
“These areas highlight the need for more research to address the limitations of the current study and investigate the variety of factors impacting DVA following cataract surgery,” he concluded.
References
- Lombardo M, Lombardo, G. Wave aberration of human eyes and new descriptors of image optical quality and visual performance. J Cataract Refract Surg. 2010;36(2):313-31.
- Maloney RK, Bogan SJ, Waring GO. Determination of corneal image-forming properties from corneal topography. Am J Ophthalmol. 1993;115(1):31-41.
- Wu T, Wang Y, Li Y, Li Y, Jiang X, Li X. The impact of corneal higher-order aberrations on dynamic visual acuity post cataract surgery. Front Neurosci. 2024;18:1321423.
Editor’s Note: A version of this article was first published in CAKE Magazine Issue 24.
