Immediate effect of a tear enhancer and meibomian gland expression on the corneal surface and whole eye higher order aberrations

Higher order aberrations in keratoconus‏

INTRODUCTION

Keratoconus is a progressive disorder of the cornea that causes thinning (Sedaghat et al. in Sci Rep 11(1):11971, 2021), ectasia, and irregular astigmatism, resulting in poor visual acuity that cannot be corrected with standard sphero-cylindrical spectacle lenses. One feature distinguishing keratoconic corneas is ocular aberrations, manifesting up to five or six times the amount of higher-order aberrations than a normal, healthy eye. These aberrations can cause visual disturbances even at the very early stages of the disease.

METHODS

In the past, a diagnosis was derived from clinical symptoms, but technological advances have revealed multiple pre-clinical features, allowing for the differentiation between keratoconic and normal eyes at a much earlier stage. These include anterior and posterior corneal surface elevations, the corneal pachymetry profile, corneal epithelial patterns, wavefront aberration metrics, and corneal biomechanics (Sedaghat et al. in Sci Rep 11(1):11971, 2021).This review discusses the aberrations associated with keratoconus, how to measure them, and treatment methods to minimize their negative influence.

CONCLUSIONS

Early diagnosis can lead to early treatment and may allow for arresting progression, thereby improving the long-term prognosis. With the acceleration of refractive surgery, it is important to identify patients with keratoconus, as they are usually contraindicated for refractive surgery.

Analysis of the Changes and Possible Reasons in Aberrations before and after Surgery in Patients with Concomitant Exotropia

Objective. The objective is to observe the changes in aberrations before and after surgery in patients with common horizontal strabismus and to analyze the possible reasons for the changes. Methods. Forty eyes of 40 cases with concomitant exotropia who underwent strabismus correction at the Ophthalmology Department of Nantong University Hospital from October 2020 to July 2021 were included in this study, all of whom underwent unilateral lateral rectus recession combined with a medial rectus resection in the same eye. Aberration parameters were measured 1 day before surgery and 1 week, 1 month, 3 months, and 6 months after surgery. Differences in the indicators at each time period were compared by analysis of variance (ANOVA) of repeated measures data for a single factor, and data were analyzed using SPSS 25.0 statistical application software. Results. 5 mm pupil diameter: the preoperative and postoperative RMS of total aberration showed statistically significant difference ( $P<0.01$ ). Postoperation test (Bonferroni method) and preoperative comparison at each period after surgery showed statistically significant differences between 6 months after surgery ( $P=0.002$ ) and preoperative comparison. The preoperative and postoperative comparison of RMS in LOAs was statistically significant ( $P<0.01$ ); postoperative test (Bonferroni method) and preoperative comparison showed that there were statistically significant differences between 1 week ( $P=0.033$ ) and 6 months ( $P=0.002$ ) after operation. The difference of RMS of defocus before and after operation was statistically significant ( $P<0.01$ ); postoperation test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference between 6 months after operation ( $P=0.007$ ) and preoperative comparison. There was statistically significant difference in preoperative and postoperative RMS of HOAs ( $P=0.013$ ). Postoperative test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference 6 months after surgery ( $P=0.03$ ). The RMS of secondary astigmatism showed a statistically significant difference before and after operation ( $P=0.001$ ), and the postoperation test (Bonferroni method) showed a statistically significant difference 6 months after operation ( $P=0.002$ ). In 5 mm pupil diameter, the preoperative and postoperative RMS of total aberration showed statistically significant difference ( $P<0.01$ ), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery ( $P=0.034$ ), 3 months after surgery ( $P=0.033$ ), and 6 months after surgery ( $P=0.003$ ). The preoperative and postoperative comparison of RMS in LOAs was statistically significant ( $P<0.01$ ), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery ( $P=0.04$ ), 3 months after surgery ( $P=0.034$ ), and 6 months after surgery ( $P=0.004$ ). The difference of RMS of defocus before and after surgery was statistically significant ( $P=0.002$ ), and the comparison between postoperation test (Bonferroni method) and preoperation showed that the difference was statistically significant 6 months after surgery ( $P=0.027$ ). The RMS of astigmatism showed statistically significant difference before and after operation ( $P=0.002$ ), and the postoperation test (Bonferroni method) showed statistically significant difference between 6 months after operation ( $P=0.009$ ) and before operation. Conclusion. We found that horizontal rectus surgery had a transient effect on LOAs and almost no effect on HOAs. Long-term follow-up is recommended after strabismus surgery to observe eye position and binocular visual function. Because of the high prevalence of strabismus in adolescents, long-term observation of the eye axis and aberration is recommended.

Changes in visual quality with soft contact lenses after the instillation of hyaluronic acid eye drops

PURPOSE

To evaluate the changes in visual function and anterior surface aberrations during soft contact lens (SCL) wear after the instillation of hyaluronic acid (HA) eye drops with different viscosity.

METHODS

A prospective, randomized, and participant-masked study was performed. Twenty healthy participants (25.4 ± 2.6 years) were evaluated. Hydrogel (Ocufilcon D) and silicone-hydrogel (Somofilcon A) SCL were randomly assigned to both eyes of the same participant. Visual function in terms of high- and low-contrast corrected distance visual acuity (CDVA) and anterior contact lens surface aberrations (RMS HOA) were measured before and after the instillation, at different times, of different eye drops: saline (control) and 0.1%, 0.2%, and 0.3% HA.

RESULTS

Compared with the saline solution, during hydrogel SCL wear, there was an improvement (P < 0.05) in high-contrast CDVA after 3 and 10 min with 0.1% HA, and after 5 and 20 min with 0.2% HA. During silicone-hydrogel SCL wear, there was a deterioration (P < 0.05) in high-contrast CDVA after 1 and 30 min with 0.3% HA. Additionally, during silicone-hydrogel SCL wear, there was also a deterioration (P < 0.05) in low-contrast CDVA after 5 and 20 min with 0.3% HA. In terms of RMS HOA, there were no clinically relevant changes with both SCL.

CONCLUSIONS

The instillation of HA eye drops could have a different effect on visual quality depending on their concentration of HA, the contact lens material, its surface ionicity, or other physicochemical properties that should be studied in future studies.

Effect of Refresh Plus® preservative-free lubricant eyedrops on tear ferning patterns in dry eye and normal eye subjects

Purpose

To evaluate the tear ferning patterns in dry eye and normal eye subjects in the 3 hours following application of Refresh Plus^® preservative-free lubricant eyedrops.

Methods

Thirty men with dry eye (mean age 22.14±2.34 years) and 30 age-matched men with normal eyes (mean age 23.91±3.24 years) were enrolled. Eyes were classified as normal or dry based on their Ocular Surface Disease Index score, tear meniscus height, and noninvasive tear breakup time. The tear ferning test was performed before and 30, 60, 120, and 180 minutes after application of a Refresh Plus eyedrop into the right eye in each subject.

Results

There was a significant change in tear ferning grade after application of Refresh Plus eyedrops (P=0.02, Wilcoxon test) in the group with dry eye, but not in the normal eye group (P=0.19, Wilcoxon test). The correlation of tear ferning grade was moderate (r=0.484, P=0.049) at 60 minutes after application of the eyedrops and strong at 120 minutes (r=0.560, P=0.019) and 180 minutes (r=0.726, P=0.001). There was also a strong correlation (r=0.865, P=0.001) between tear ferning grades obtained 120 and 180 minutes after application. In the normal eye group, there was a moderate (r=0.407, P=0.029) correlation between tear ferning grades obtained before and 60 minutes after application of the eyedrops. There was also a strong correlation (r=0.532, P=0.003) between tear ferning grades obtained 120 and 180 minutes after application.

Conclusion

Tear ferning patterns improved significantly after application of Refresh Plus preservative-free lubricant eyedrops in subjects with dry eye. Artificial tears containing sodium carboxymethylcellulose, such as Refresh Plus, can be used to improve tear ferning patterns in dry eye for at least 3 hours.