| PurposeTo evaluate clinical outcomes of femtosecond laser-assisted lenticule intrastromal keratoplasty(LIKE)for the treatment of moderate to high hyperopia,and to analyze the related factors of refractive effect corrected by LIKE.MethodThis prospective study enrolled patients with moderate to high hyperopia who underwent LIKE to correct hyperopia.Inclusion criteria were attempted spherical equivalent between+3.00 and+10.00 diopters(D).Femtosecond laser created the corneal flap,under which an allogeneic refractive lenticule was implanted.Lenticule diameter was 6.0 to 6.5 mm,the treatment was centered on the corneal vertex.In addition,we retrospect the consecutive case series that underwent laser-assisted in situ keratomileusis(LASIK)to correct hyperopia at our institution during the same period.1.Standard refractive outcomes were performed by comparing the LIKE group for evaluating clinical effects in correcting moderate to high hyperopia.The treatment effects were analyzed by the corrective efficacy,safety,accuracy,and stability.2.A tangential curvature preoperative to last visiting postoperative difference map was generated for each eye in LIKE group and LASIK group in analyzing achieved optical zone and optical zone centration offset.And the introduction of postoperative corneal higher-order aberrations was analyzed by Pentacam "Zernike analysis".3.Anterior segment optical coherence tomography(AS-OCT)was used to obtain a corneal epithelial thickness topography with a diameter of 9 mm,and compared the characteristics of corneal epithelial thickness remodeling after two surgical procedures to correct hyperopia.4.Pentacam "corneal densitometry analysis" pattern was used to analyze the changes of corneal densitometry in the two groups at 3 months after the operation.Result1.This study enrolled 10 eyes in LIKE group and 12 eyes in LAS IK group.No serious complications occurred in LIKE.In LIKE,the uncorrected distance visual acuity(UDVA)in the early postoperative period(1 week to 2 weeks)after the correction of moderate to high hyperopia(SEQ=+6.25±0.91 D)was equal to or better than the preoperative best-corrected visual acuity(CDVA)in 3 eyes(30%),postoperative CDVA reached or better than preoperative CDVA in 7 eyes(70%).In the postoperative early period,there may be obvious dry eye and poor corneal transparency.Until the mid-and long-term postoperation,the visual acuity of the patients was improved rather than previously.7 eyes(70%)of postoperative UDVA reached or better than preoperative CDVA,and 9 eyes(90%)of postoperative CDVA reached or better than preoperative CDVA.There were 7 eyes(70%)and 10 eyes(100%),respectively,in LIKE of corrective accuracy within ±0.50 D and ±1.00 D.Compared to postoperatively 3 months,the refractive outcome was increased 0.02±0.20 D after 6-month surgery.The corrective accuracy of astigmatism was poor in LIKE,postoperatively,2 eyes(20%)of the cylinder were beyond 1.00 D,and 6 eyes(60%)of astigmatic axial deviation ≥±15°.2.This study enrolled 10 eyes in LIKE group and 12 eyes in LAS IK group.The optical zone diameter(6.48±0.06 mm)in LIKE group was similar to LASIK group(6.58±0.15 mm).But the achieved optical diameter/area(5.30±0.34 mm,20.92±2.99 mm2)even after LIKE corrected higher SEQ(SEQ=+6.25±0.91 D)were significantly larger than those outcomes(4.83±0.19 mm,17.09±1.40 mm2;P=0.003,P=0.02)of LASIK group(SEQ=+3.50±1.04 D).The centration offset(0.39±0.14 mm)of LIKE was slightly higher than that in LASIK(0.33±0.19 mm,P=0.248).Corneal Q-value was induced for each diopter in LIKE corrected(-0.15±0.06),which was significantly lower than that in the control group.The induction of corneal Q-value per corrected diopter in LIKE was significantly lower than that in control group(-0.29±0.07,P<0.001).Besides,the induction of corneal spherical aberration in LIKE(-0.044±0.056μm/D)was slightly lower than that in LASIK group(0.053±0.045μm/D,P=0.468).3.This study enrolled 10 eyes in LIKE group and 6 eyes in LASIK group.The corneal epithelial thickness remodeled after LIKE correcting moderate-to high-hyperopia(SEQ=+6.30±0.93 D)was characterized as follows:central zone(within 2 mm)and paracentral area(2～5 mm)corneal epithelium thickness were significantly thinner(the difference between preoperative and postoperative were 4.53±3.23 μm and 5.89±2.42 μm,respectively),but the mid-peripheral(5-7 mm)and peripheral areas(7～9 mm)were unchanged significantly.There were parts in the mid-peripheral and peripheral annular zone of epithelial thickness that was thicker than before.In LIKE,the central epithelial thickness thinning was unrelated to the magnitude of refraction that corrected.4.This study enrolled 9 eyes in LIKE group and 11 eyes in LASIK group.In LIKE,the corneal densitometry of the anterior corneal layer in the midperiphery(6-10 mm)annular area(22.32±2.41)was increased rather than before(20.27±3.05)after correcting moderate to high hyperopia(SEQ=+6.21±1.19 D),(P=0.015),other zones were unchanged between preoperation and postoperation.After LIKE,the change corneal densitometry in all zones were similar to those in the LASIK group with correction.After LIKE surgery,the change in corneal densitometry in all zones was similar to those outcomes after LASIK that corrected SEQ+3.66±0.92 D(P>0.05).In LIKE,there was no significant relation among corneal densitometry in the anterior or total corneal layer,corrected refraction,efficacy index,or safety index.(P>0.05).Conclusion1.The poor corrective safety and efficacy in the early stage after LIKE correcting moderate and high hyperopia,until to the mid-to long-term postoperative,the visual acuity was gradually improved.The predictability and accuracy of correcting astigmatism by LIKE was poorer than that by LASIK procedure,but it can be improved by enhancement procedure following LIKE.2.The mean achieved optical zone of LIKE was found to be larger than the mean achieved optical zone of hyperopic LASIK,which may be the reason of refractive stability after LIKE,which also may reduce the risk of refractive regression postoperatively.The larger optical zone was achieved by LIKE,that may relate to the less corneal irregular astigmatism was induced,and it may tolerant more optical centration offset.3.The degree of remodelling in the corneal epithelial thickness was lower after LIKE correcting hyperopia,which may explain why achieved more refractive stability after LIKE.Additionally,the small degree of central corneal epithelial thickness thinning that may be tolerant the higher refraction after LIKE procedure.4.The change of corneal densitometry in the early stage after LIKE may relate to the healing reaction of the corneal flap,but it has not been related to the degree of hyperopia that LIKE surgery corrected.It also has no evidence showing that the more densitometry of cornea postoperatively,which would detriment the corrective effect and safety. |
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