Comparison of long-term results after manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty for keratoconus

AIM: To compare long-term postoperative outcomes of manual and femtosecond assisted corneal trephination in deep anterior lamellar keratoplasty(FS-DALK) for keratoconus.METHODS: In the retrospective study, 17 consecutive eyes that underwent vertical side cut incision FS-DALK and 22 eyes that underwent trephine incision DALK were collected over a 2-year period. Main measurements included postoperative uncorrected-visual acuity(UCVA), corrected distance visual acuity(CDVA), refractive sphere and cylinder, manifest refraction spherical equivalent(MRSE), flat and steep corneal keratometry(K1 and K2), endothelial cell density(ECD), and time of epithelium healing and suture removal.RESULTS: Groups were comparable for diagnosis and preoperative visual acuity. Follow-up averaged 23 mo(range, 12-36 mo). At 12 mo, the mean UCVA was better in the manual-DALK group(P=0.039), and the refractive sphere was lower in the FS-DALK group(P=0.040). MRSE between groups differed at 1, 6, and 12 mo postoperatively(P=0.047, 0.025, 0.042, respectively). Mean CDVA, cylinder, K1, K2,corneal astigmatism, ECD, and time of epithelium healing were similar between groups. Stability of MRSE, ECD, and K1 returned sooner after FS-DALK. Initial loosened suture removal time was earlier in the manual-DALK group(P=0.042) while complete suture removal time was similar(P=0.122).CONCLUSION: Manual and femtosecond assisted corneal trephination in DALK are options for advanced keratoconus. FS-DALK do not result in improved visual acuity but it is more stable during the follow-up period. FSDALK in the present form show limited benefit, so surgical design and parameters still need to be optimized and explored.

Correlation of basic indicators with stages of keratoconus assessed by Pentacam tomography

AIM: To evaluate the diagnostic efficiency of basic indicators and find characteristic indicators for keratoconus (KC) at adjacent stages, and to assess the progression pattern of KC. METHODS: One hundred and eight (41 subclinical, 40 moderate, and 27 severe) keratoconic patients (108 eyes) and 105 myopic patients (105 eyes) as controls were recruited in this prospective, comparative case series study. Pentacam topography was performed. Receiver operating -characteristic curves were used to get the characteristic indicators. RESULTS: The most efficient distinguishing index between the subclinical KC and the controls was posterior elevation value (PEV, AUC =0.882), with the highest specificity being 93.8%. Corneal thickness (AUC=0.852) and posterior inferior-superior value (I-S) ranked second and third (AUC=0.776). When KC became moderate, PEV remained to be of the highest diagnostic efficiency (AUC=0.988), followed by the anterior elevation value (AUC=0.986) and other parameters of anterior surface. The diagnostic value increased significantly in the anterior curvature indices (all AUC >0.900) and appeared in the anterior best fitting sphere radius (AUC= 0.919) when KC developed into the severe stage. CONCLUSION: In the subclinical stage of KC, PEV, thickness, and posterior I-S had important diagnostic values, and elevation values remained most efficient when KC developed to the moderate stage. The anterior curvature indices were most characteristic when KC became severe. KC first appeared in the inferior cornea of posterior surface, but the feature of protrusion formed at the moderate stage.

Outcomes of different lines of keratoconus management in a tertiary eye center in north China

AIM: To evaluate the treatment selections and outcomes of keratoconus and discuss the grading treatment of keratoconus.METHODS: Medical records of 1162 patients(1863 eyes) with keratoconus treated with rigid gas permeable(RGP), corneal collagen crosslinking, and keratoplasty were reviewed. The patients were grouped according to the CLEK Study. The advanced group was further divided into a <60 D group and >60 D group. The best-corrected visual acuity(BCVA) and topographic data before and after treatment were recorded.RESULTS: In the 761 eyes with steep K<52 D, nonsurgical management accounted for 83.4%, while in the 735 eyes with steep K>60 D, surgical management accounted for 90.6%. A total of 618 eyes had improved BCVA at the final fol ow-up point(>18 mo, P<0.001). When steep K was <52 D, the BCVA in the RGP group was better than those with lamellar keratoplasty(LKP;P=0.028). When steep K was >52 D, the BCVA and topographic astigmatism outcomes showed no differences among the treatment groups. When steep K was >60 D, the BCVA in eyes treated with LKP was worse than those with steep K<60 D(P=0.025). The incidence of steep K progression in the RGP group was higher in advanced group(20.0% vs 10.8%, P=0.019). The probability of future keratoplasty in RGP was higher in advanced group(14.8% vs 7.0%, P=0.027). The incidence of steep K progression in the corneal collagen crosslinking(CXL) group was higher in advanced group(32.3% vs 8.5%, P=0.007). Multivariate logistic regression revealed the following related factors for treatment options: steep K [odds ratio(OR)=1.208, 95%CI: 1.052-1.387], TA(OR=1.171, 95%CI: 1.079-1.270), and TCT(OR=0.978, 95%CI: 0.971-0.984). The level of steep K, TA, and TCT all relates to the treatment choices of both keratoplasty and non-keratoplasty, while steep K provided the highest diagnostic accuracy(AUC=0.947, P<0.001).CONCLUSION: Steep K is an important grading treatment indicator. When steep K is <52 D, RGP lenses should be recommended. It is the best time for LKP when the steep K ranges from 52 to 60 D.