A Short-term Outcome Of Avedro Accelerated Corneal Cross-linking For Keratoconus

Objective:This project analyzes the short-term outcome including the efficacy and safety of Avedro accelerated(30mW/cm2,4 minites)corneal cross-linking for keratoconus.The major parameters consist of keratometry,corneal pachymetry,uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),manifest refraction,demarcation line,corneal densitometry,endothelial cell density(ECD)and intraocular pressure(IOP).Material and Method:This is a retrospective and observational case series.80 eyes of 64 patients with verified primary keratoconus received Avedro accelerated corneal cross-linking in the Ophalthmology Center of Sir Run Run Shaw Hospital from 2016 March to October.Corneal stroma was soaked with 0.1%riboflavin solution(VibeX Rapid),and the irradiance was set as 7.2J/cm2(365nm-UVA,30mW/cm2,4minutes).Reepithelization and complication were carefully observed in the 1st week.IOP,visual acuity,Pentacam HR(scheimflug tomography),AS-OCT,confocal microscopy were measured from preoperatively,to the 1st,3rd,6th month postoperatively.Repeated measures analysis of variance(ANOVA)was used for analyzing the major parameters.p<0.05 is considered as statistical significance.Result:This project analysed 80 eyes and found:(1)Statistical difference by small amplitude in corneal curvature and pachymetry was observed 1 month after the treatment.Kmax was changed from 48.33±4.12 D to 49.41 ±4.47 D,p<0.01.The steep curvature of anterior corneal surface was changed from 49.23±4.69 D to 50.00±5.13 D,p<0.01.The flat curvature of anterior corneal surface was changed from 45.95±3.66 D to 46.35±4.00 D,p<0.01.Thinnest corneal thickness was changed from 469.7±38.3μm to 457.6±38.6μm,p<0.05.However,the parameters montioned above were all restored as before at the later follow-up visits.The average densitometry values of Φ 0 to 2mm increased in every follow-up of early phase after treatment until the 6th month.There were no statistical differences from before and after the treatment in the steep and flat curvature of posterior surface.(2)There were no statistical differences from before and after the treatment in manifest refraction.(3)Endothelial cell density decreased at 1st month after treatment,and restored later similarly.(4)97.5%of the targeted eyes formed visible demarcation line round 1st month through AS-OCT postoperatively,and the average depth was 241 ±78μm.(5)There were 3 cases of infection.Conclusion:Avedro accelerated(30mW/cm2,4 minites)corneal cross-linking is effective and safe during the 6 months postoperatively.(1)The corneal curvature and visial acuity were stable.Although corneal curvature and pachymetry deteriorated in small amplitude in the early phase,they all restored at the 3rd and 6th month follow-up later.In the other hand,we haven’t found statistically significant improvement within 6 months either,though the mean values show a promising tendency.(2)Endothelial cell density,the average densitometry values of Φ 0 to 2mm,and IOP are stable.The process of epithelization is nomal.The cases of infection were diagnosed in time,and appropriate dose of antibiotics were prescribed without delay.The infections were all in control within one week.There is no case ended up with corneal scar.