Application study of rigid gas permeable contact lens in patients with traumatic corneal irregular astigmatism

Abstract

Objective To evaluate the clinical value of rigid gas permeable contact lens (RGP-CL) in patients with traumatic corneal irregular astigmatism. Methods Eighteen consecutive patients (18 eyes) with traumatic corneal irregular astigmatism were fitted RGPCL.All patients were followed up at least 6 months.Preoperative data included:age,sex,eye,interval between RGPCL fitting and complete sutures removal,status of lens,uncorrected visual acuity (UCVA),spectacle visual acuity (SVA),location and size of the corneal scar,corneal astigmatism.Post-contact lens fitting data included:RGPCL visual acuity (RGPCLVA),duration of contact lens wear,the reason for drop ping out of contact lens wear,contact lens-related complications,whether or not the patient was successful in wearing the contact lcns.RGPCL fitting was considered successful if the patient judged the wearing of RGPCL to be satisfactory enough at least 8 hours of daily wear throughout the follow-up period.Decimal acuity was converted to 5-logMAR value.Data analysis used SPSS 16.0 for the paired samples t-test,two independent sample t-test and analysis of covariance. Results The average age was 20.94±13.35 years (range 5-45 years),five eyes were pseudophakic,one was aphakic and other twelve were phakic.According to the location of the corneal scar,it was found that nine eyes were in zone 1 and other nine in zone 2.The average length of scar was 4.04±2.23 mm (range 1.50-8.33 mm).The difference in the length of scar between zone 1 and zone 2 was found to be not statistically significant (t =-0.967,P =0.348).The interval from complete sutures removal to contact lens fitting was averaged 5.67±5.52 months (range 3-22 months).Mean UCVA was 4.2±0.5 (range 3.0-4.9).Mean SVA was 4.6±0.3 (range 4.0-4.9).Mean RGPCLVA was 4.9±0.1 (range 4.4-5.1).The visual acuities with contact lens were significantly better than with spectacles (t=4.143,P ＜0.000).RGPCLVA was 1 line better in 7 eyes,2-4 lines in 6 eyes,more than 5 lines in 4 eyes.Between zone 1 and zone 2,there was no significant difference in RGPCLVA (F =0.826,P =0.379),and no significant difference in SVA (F =5.128,P=0.040).However,the improvement in visual acuity with RGPCL over spectacles was found to be significant (F =7.286,P =0.017).It was found that the length of corneal scar had no significant effect on RGPCLVA,SVA,UCVA and the improvement in visual acuity.During 6 months of follow-up,there was no habitual dislocation of contact lens.Punctuate epithelial keratitis was observed in 2 eyes; four patients were successfully fit with RGPCL,two of them were less than 10 years of age,two were between 10 to 20 years and none was more than 20 years.The reasons for dropping out of RGPCL wear were initial ocular discomfort,recurrent red eye and lack of motivation. Conclusions Compared with spectacle visual acuity,RGPCLVA is a more ideal judgment index to evaluate the best corrected visual acuity in patients with traumatic corneal irregular astigmatism.However,RGPCL may not be an ideal and long-term choice of vision correction for patients with traumatic corneal irregular astigmatism. Key words: Ocular trauma; Corneal irregular astigmatism; RGPCL