| BackgroundKeratoconus is a kind of degenerative disease with progressive corneal protrusion and thinning,which can affect the patients' visual acuity and daily lives.As a new method to halt the progress of keratoconus,corneal collagen crosslinking can create new chemical bonds through the interaction between roboflavin and UVA to increase the corneal biomechanical properties.And its effect of adult patients has been proven by a large number of documents in recent years.However,there is little research on the treatment in teenage keratoconus.Lives of teenage patients,a special group,can be affected seriously.This study is conducted to follow up the treated patients to evaluate the effectiveness and safety of riboflavin/UVA mediated epithelium-off corneal collagen crosslinking in treating teenage keratoconus.ObjectiveTo evaluate the safety and efficacy of epithelium-off corneal collagen crosslinking induced by riboflavin and ultraviolet A(UVA)light for keratoconus in teenagers.MethodsA total of 33 eyes of 22 teenage patients aged from 14 to 18 with primary keratoconus were enrolled in this retrospective self-control study.Pre-and postoperative examinations were collected:uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),Kmax value,thinnest corneal thickness(TCT),and endothelial cell counts(ECD).And complications were observed during the whole process.Antibiotic eye drops were used for 3 days before treatment in prevention of infection.Central corneal epithelium was removed by microkeratome after topical anesthesia under sterile condition and isotonic riboflavin solution was applied to cornea every 3 minutes for 30 minutes.After the corneal thickness reached 400?m measured with OCT(optical coherenece tomography)and saturation of the corneal stroma with the presence of riboflavin in the anterior chamber by slit lamp,UVA with 370nm wavelength(irradiation energy density-3mW/cm2,irradiation diameter-9mm,irradiation distance-5cm)was used for 30 minutes.During irradiaton,we instilled isotonic riboflavin solution to the cornea frequently.Then a corneal contact lens was given and eye drops were used.Contact lens was removed after reepithlialization and steroid eye drops were added.Statistical analysis was performed using SPSS20.0.One way repeated ANOVA test was used to compare pre-and postoperative parameters.P<0.05 was considered statistically significant.Results1.Visual acuity:Mean UCVA(uncorrected visual acuity)and BCVA(best-corrected visual acuity)measured as LogMAR were 0.82±0.35 and 0.43±0.33 preoperatively,which improved to 0.71±0.33 and 0.25±0.23 after treatment respectively.The difference between pre-and postoperation of UCVA and BCVA were statistically significant.Furthermore,UCVA of 24 eyes were improved by at least 1 lines and BCVA of 23 eyes were improved by at least 1 lines.2.Kmax value:The Kmax value was 62.45±11.24D preoperatively and decreased to 60.37±9.74D postoperatively by significant difference.And Kmax of 20 eyes were decreased by more than 1 D postoperatively compared to preoperatively.3.Thinnest corneal thickness:Mean thinnest corneal thickness decreased from 442.69±43.47?m at baseline to 427.44±41.75?m after treatment by statistically significant difference.4.Endothelial cell counts:Mean endothelial counts were 3038±361/mm2 before treatment and 2998±345/mm2 after treatment.No statistically significant differences were found,and there was no obvious morphological change.All corneal epithelium were recovered in 5 days and no complications occurred during the process such as corneal infection,decompensation of corneal endothelium,damage of lens and retina.ConclusionsThe riboflavin/UVA mediated epithelium-off corneal collagen crosslinking is safe and effective in treating teenagers with keratoconus by improving the visual acuity and keratometry values at 1 year postoperatively. |
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