Background: To investigate early change of corneal aberrations after 2.8-mm superior incision phacoemulsification.

Methods: This study comprised 80 eyes of 75 patients. All the patients underwent phacoemulsification with monofocal foldable intraocular lens (IOLs) implanted through a 2.8-mm superior corneal incision. The anterior corneal wavefront aberrations for the 6.0-mm pupillary diameter was measured by iTrace wavefront aberrometer (Tracey Technologies, Inc.) preoperatively and 1 month postoperatively. Changes of root mean square (RMS) values of Z(3, -3), Z(3, 3), Z(3, -1), Z(3, 1), and Z(4, 0) and total high order aberration (HOA) were evaluated.

Results: The uncorrected and corrected visual acuities improve significantly (P<0.001). No significant postoperative changes were observed in spherical aberration (P=0.652). Significant changes in vertical coma and vertical trefoil (0.005±0.214 vs. -0.049±0.242, P=0.037; -0.141±0.222 vs. -0.258±0.359, P=0.001; separately). However, the total HOAs increased after cataract surgery (0.567±0.161 vs. 0.688±0.343, P<0.001).

Conclusions: Corneal vertical coma and vertical trefoil changes significantly in 2.8 mm superior corneal incision phacoemulsification cataract surgery. In addition, those had a trend to negative direction.

Background: To investigate early change of corneal aberrations after 2.8-mm superior incision phacoemulsification.

Methods: This study comprised 80 eyes of 75 patients. All the patients underwent phacoemulsification with monofocal foldable intraocular lens (IOLs) implanted through a 2.8-mm superior corneal incision. The anterior corneal wavefront aberrations for the 6.0-mm pupillary diameter was measured by iTrace wavefront aberrometer (Tracey Technologies, Inc.) preoperatively and 1 month postoperatively. Changes of root mean square (RMS) values of Z(3, -3), Z(3, 3), Z(3, -1), Z(3, 1), and Z(4, 0) and total high order aberration (HOA) were evaluated.

Results: The uncorrected and corrected visual acuities improve significantly (P<0.001). No significant postoperative changes were observed in spherical aberration (P=0.652). Significant changes in vertical coma and vertical trefoil (0.005±0.214 vs. -0.049±0.242, P=0.037; -0.141±0.222 vs. -0.258±0.359, P=0.001; separately). However, the total HOAs increased after cataract surgery (0.567±0.161 vs. 0.688±0.343, P<0.001).

Conclusions: Corneal vertical coma and vertical trefoil changes significantly in 2.8 mm superior corneal incision phacoemulsification cataract surgery. In addition, those had a trend to negative direction.

Background: Few prevalence studies on intermittent exotropia (IXT) based on Chinese populations. Furthermore, longitudinal change in this pattern within a local setting has not been reported in the past. This study aims to determine the pro?le of children with IXT in China.

Methods: A total of 7,537 subjects from nine multi-layer primary and secondary schools participated in this investigation. The position of eyes was examined by using Hirschberg test and alternate cover test. The obtained results were classi?ed according to respective features and analyzed statistically.

Results: The prevalence of IXT among the participants was 7.98%, accounting for 73.04% of all types of strabismus. Junior high school students had a lower prevalence of IXT than elementary and senior high school counterparts. Logistic regression analysis showed that IXT was mainly found in male pupils at high grades in rural areas and in male secondary students at high grade in urban regions.

Conclusions: IXT was shown to be more prevalent than other types of strabismus in Chinese children. Furthermore, the distribution and characteristics of IXT greatly varied among participants.

Background: Few prevalence studies on intermittent exotropia (IXT) based on Chinese populations. Furthermore, longitudinal change in this pattern within a local setting has not been reported in the past. This study aims to determine the pro?le of children with IXT in China.

Methods: A total of 7,537 subjects from nine multi-layer primary and secondary schools participated in this investigation. The position of eyes was examined by using Hirschberg test and alternate cover test. The obtained results were classi?ed according to respective features and analyzed statistically.

Results: The prevalence of IXT among the participants was 7.98%, accounting for 73.04% of all types of strabismus. Junior high school students had a lower prevalence of IXT than elementary and senior high school counterparts. Logistic regression analysis showed that IXT was mainly found in male pupils at high grades in rural areas and in male secondary students at high grade in urban regions.

Conclusions: IXT was shown to be more prevalent than other types of strabismus in Chinese children. Furthermore, the distribution and characteristics of IXT greatly varied among participants.

Background: Corneal ectasia is a serious complication after laser in situ keratomileusis (LASIK). Ideally, patients at risk of ectasia should be identified prior to laser as unsuitable for LASIK, however, at present, there is no absolute test, system, or marker that can unequivocally identify patients at risk of developing ectasia. It has been suggested that changes in the forward protrusion of the posterior cornea or posterior corneal elevation (PCE) may be a key to the early detection of ectasia after LASIK. The purpose of this study was to examine the long term changes of the PCE after myopic LASIK using the ORBSCAN® IIz (Bausch & Lomb, Rochester, USA) and to evaluate the contributory preoperative factors to PCE changes.

Methods: This was a retrospective longitudinal case series. Forty-two eyes of 23 consecutive myopic patients who underwent uneventful LASIK surgery 6 years ago were recalled for a postoperative follow-up examination using the ORBSCAN® IIz to determine the elevation changes to the posterior corneal surface from the preoperative measurements. A forward shift of the posterior surface was given a negative value. Correlation analyses and forward stepwise regression analyses were performed to evaluate the effect of each of the preoperative parameters on the changes in PCE. Statistical and graphical analyses were performed.

Results: There was no statistical difference between the mean best-fit sphere (BFS) pre-LASIK and 6 years postop (P=0.25). Forty-two post-LASIK eyes had a mean posterior displacement of -9.38±9.84 μm (range, 12 to -31 μm) 6 years after LASIK. Forward stepwise multiple linear regression analysis indicated that the ablation spherical equivalent (ASE) was the only indicator of the forward shift of the posterior cornea after LASIK.

Conclusions: The present study identified a significant forward shift of the posterior cornea 6 years after LASIK. The ASE was the most significant prognostic determinant for forward protrusion of the posterior cornea after LASIK. 

Background: Corneal ectasia is a serious complication after laser in situ keratomileusis (LASIK). Ideally, patients at risk of ectasia should be identified prior to laser as unsuitable for LASIK, however, at present, there is no absolute test, system, or marker that can unequivocally identify patients at risk of developing ectasia. It has been suggested that changes in the forward protrusion of the posterior cornea or posterior corneal elevation (PCE) may be a key to the early detection of ectasia after LASIK. The purpose of this study was to examine the long term changes of the PCE after myopic LASIK using the ORBSCAN® IIz (Bausch & Lomb, Rochester, USA) and to evaluate the contributory preoperative factors to PCE changes.

Methods: This was a retrospective longitudinal case series. Forty-two eyes of 23 consecutive myopic patients who underwent uneventful LASIK surgery 6 years ago were recalled for a postoperative follow-up examination using the ORBSCAN® IIz to determine the elevation changes to the posterior corneal surface from the preoperative measurements. A forward shift of the posterior surface was given a negative value. Correlation analyses and forward stepwise regression analyses were performed to evaluate the effect of each of the preoperative parameters on the changes in PCE. Statistical and graphical analyses were performed.

Results: There was no statistical difference between the mean best-fit sphere (BFS) pre-LASIK and 6 years postop (P=0.25). Forty-two post-LASIK eyes had a mean posterior displacement of -9.38±9.84 μm (range, 12 to -31 μm) 6 years after LASIK. Forward stepwise multiple linear regression analysis indicated that the ablation spherical equivalent (ASE) was the only indicator of the forward shift of the posterior cornea after LASIK.

Conclusions: The present study identified a significant forward shift of the posterior cornea 6 years after LASIK. The ASE was the most significant prognostic determinant for forward protrusion of the posterior cornea after LASIK.