Autologous Serum Eye Drops Accelerate Epithelial Healing After LASEK

Effect of Autologous Serum Eye Drops on Corneal Haze after Corneal Cross-linking

SIGNIFICANCE

Corneal haze remains a frequent post-operative finding in patients undergoing corneal cross-linking. It has been shown that autologous serum tears promote epithelial healing and reduce post-operative pain; however, the role in the prevention of corneal haze has not been reported.

PURPOSE

This study aimed to compare the effect of autologous serum tears versus preservative-free artificial tears on the prevention and resolution of post-cross-linking corneal haze.

METHODS

A retrospective cohort study was conducted in a sample population from one surgeon at a tertiary eye center from 2016 to 2019. Seventy-six eyes of consecutive patients who underwent cross-linking were included. Records were reviewed for corneal Scheimpflug densitometry values and maximum keratometry, epithelial healing time, and the use of either autologous serum tears or preservative-free artificial tears. Corneal densitometry values, expressed in standardized grayscale units (GSU), were recorded for the anterior 150-μm corneal stroma and in the 0.0 to 2.0 mm and 2.0 to 6.0 mm zones.

RESULTS

Forty-four eyes received autologous serum tears, whereas 32 eyes received preservative-free artificial tears. The baseline GSU of the anterior stromal 0 to 2 mm annulus and the 2 to 6 mm annulus did not significantly differ between groups (P = .50 and P = .40, respectively). There was a statistically significant increase in mean GSU for both anterior 0 to 2 mm and 2 to 6 mm zones between baseline and 1 month (P < .001) and 3 months (P < .001). When comparing the two groups, no statistically significant difference was found post-operatively between the mean GSU at 1 month for the anterior 0 to 2 mm (P = .38) nor the 2 to 6 mm zone (P = .12), or for the third month (P = .60 and P = .44, respectively).

CONCLUSIONS

Using Scheimpflug densitometry, we did not find a significant difference in the post-cross-linking corneal haze at 1 and 3 post-operative months between patients who use autologous serum tears and those who use preservative-free artificial tears.

Effects of the LASIK flap thickness on corneal biomechanical behavior: a finite element analysis

Background

It is well known that the biomechanical properties change after LASIK refractive surgery. One reason is the impact of flap creation on the residual stroma. The results have revealed that the change is closely related with the flap thickness in several studies. However, the quantitative relationships between the distributions of displacement and stress on the corneal surface and flap thickness have not been studied. The aim of the study was to quantify evaluate the biomechanical change caused by the LASIK flap.

Methods

By building a finite element model of the cornea, the displacement, the stress and the strain on the corneal surface were analyzed.

Results

The results showed that the corneal flap could obviously cause the deformation of the anterior corneal surface. For example, the displacement of the corneal vertex achieved 15 μm more than that without corneal flap, when the thickness of corneal flap was 120 μm thick. This displacement was enough to cause the change of aberrations in the human eyes. In the central part of the cornea, the stress on the anterior corneal surface increased with flap thickness. But the change in the stress on the posterior corneal surface was significantly less than that on the anterior surface. In addition, the stress in the central part of the anterior corneal surface increased significantly as the intra-ocular pressure (IOP) increase. Furthermore the increase of IOP had a clearly less effect on stress distribution at the edge of the cornea. Distributions of strain on the corneal surface were similar to those of stress.

Conclusions

The changes in the biomechanical properties of cornea after refractive surgery should not be ignored.

Application of autologous serum eye drops after pterygium surgery: a prospective study

PURPOSE

The study aims to determine the effect of 50% autologous serum drops (ASD) on corneal healing and patient comfort following pterygium surgery.

METHODS

Fifty eyes of 50 patients who underwent pterygium excision combined with autologous conjunctival graft were included in this prospective randomized study: in 25 eyes, 50% ASD. In the remaining 25 eyes, conventional artificial tears (CAT) were applied postoperatively until corneal epithelium had completely epithelialized. Corneal epithelium healing speed, visual analog scale (VAS) for postoperative pain assessment, conjunctival inflammation, and recurrences were evaluated. Patients were followed up for 6 months.

RESULTS

Mean corneal epithelium closure time was 3.16 ± 0.37 days (range 3 and 4 days) in ASD group and 4.96 ± 0.84 days in CAT group (range 4 and 6 days), and the difference was statistically significant (p < 0.001). VAS scores were significantly lower in ASD group than CAT group in the first 5 days after surgery. In 9 of 50 eyes, moderate conjunctival inflammation continued 1 month: 4 (16%) in ASD group and 5 (20%) in CAT group (p = 0.713). In total, pterygium recurrence was seen in 5 (10%) eyes: 2 eyes (8%) in ASD group and 3 eyes (12%) in CAT group (p = 0.637).

CONCLUSION

ASD accelerated corneal epithelial healing following pterygium surgery. ASD group had lesser pain that was seem to be related with accelerated corneal epithelial healing.

Autologous serum eye-drops and enhanced epithelial healing time after photorefractive keratectomy

BACKGROUND

The aim of the study is to test whether use of autologous serum eye-drops can provide earlier epithelial healing following the application of photorefractive keratectomy.

METHOD

Sixty patients (60 eyes) underwent photorefractive keratectomy for myopia. Thirty eyes received autologous serum drops (Study group) while 30 eyes received conventional artificial tears (Control group) after photorefractive keratectomy. An 8 mm epithelial opening was prepared with the application of 18 per cent alcohol for 20 seconds. Photorefractive keratectomy was performed using ESIRIS excimer laser (SCHWIND, Kleinostheim, Germany) with an optic zone of 6.5 mm. Total duration of epithelial healing was monitored as the main outcome measure. The comparisons were done with chi-square test and independent samples t-test. Statistical significance was considered at p < 0.05.

RESULTS

Preoperative myopic spherical refraction and ablation depths were similar in the study and control groups. The mean duration for epithelial healing was about one day shorter in the eyes receiving autologous serum compared to the eyes receiving conventional treatment (2.2 ± 0.25 days versus 3 ± 0 days, p = 0.001). All eyes achieved 6/7.5 or better uncorrected visual acuity in six months. In both groups, more than 90 per cent of eyes were within ±0.50 D of emmetropia in 12 months. No significant difference was noted for the incidence of +1 haze.

CONCLUSION

Use of autologous serum drops reduces epithelial healing duration following surface ablation for two days.