Feasibility of bimanual microincision phacoemulsification in hard cataracts

Astigmatic neutrality in biaxial microincision cataract surgery

PURPOSE

To assess the astigmatic effect of biaxial microincision cataract surgery (MICS) with insertion of an UltraChoice 1.0 Rollable Thinlens intraocular lens (IOL) in a sufficiently powered controlled study.

SETTING

Queen Elizabeth Hospital, South Australian Institute of Ophthalmology, University of Adelaide, Adelaide, Australia.

METHODS

Consecutive patients having biaxial MICS were evaluated prospectively. Keratometry was performed preoperatively and postoperatively. Vector analysis of the alteration in the keratometric cylinder was compared with that in control eyes not having surgery but having keratometry over a similar time frame.

RESULTS

There were 76 eyes in the surgical group and 74 in the control group. The right-hand incision used for IOL insertion had a mean external opening width of 2.00 mm and a mean internal width of 1.89 mm. The left-hand incision measured a mean of 1.49 mm and 1.46 mm, respectively. There was no statistically significant difference between the surgical group and the routine variability in keratometry in the untreated control group in surgically induced astigmatism (surgical group, 0.57 diopter [D] +/- 0.05 [SEM]; control group, 0.54 +/- 0.06 D; P =.660) or the degree of mean calculated flattening effect at the right-hand incision (0.01 +/- 0.06 D and -0.05 +/- 0.05 D, respectively; P = .405) or at the left-hand incision (-0.06 +/- 0.05 D and 0.03 +/- 0.06 D, respectively; P = .283).

CONCLUSION

Biaxial MICS with insertion of IOL through a temporal incision of 2.0 mm offers prospects of astigmatic neutrality in cataract surgery.

Bimanual microincisional cataract surgery technique and clinical outcome

Bimanual microincisional cataract surgery has been introduced recently as a technique for cataract surgery and it is gaining interest of many cataract surgeons in the world. Over the last few years many changes were made in the phacoemulsification machines and the intraocular lenses design which allowed bimanual microincisional cataract surgery to be safer and more efficient. The purpose of this review is to introduce the technique of bimanual microincisional cataract surgery and to review all the prospective randomized studies comparing bimanual microincisional cataract surgery and standard phacoemulsification in term of safety and efficacy parameters.

Changes in Corneal Astigmatism and High Order Aberrations After Clear Corneal Tunnel Phacoemulsification Guided by Corneal Topography

PURPOSE

To study changes in corneal astigmatism and high order aberrations after clear corneal tunnel phacoemulsification guided by corneal topography.

METHODS

All patients were randomly assigned to the test group or the control group. Corneal topography-guided clear corneal tunnel phacoemulsification followed by intraocular lens (IOL) implantation was performed on 22 eyes of 16 patients in the test group and conventional temporal corneal tunnel phacoemulsification and IOL implantation were performed on 22 eyes of 21 patients in the control group. The corneal astigmatism and high order aberrations were measured using the NIDEK OPD-Scan aberrometer and topographer preoperatively and up to 3 months after surgery. The corneal astigmatism and sixth order root-mean-square (RMS) for corneal coma, trefoil, spherical, secondary coma, and secondary spherical aberrations at 4-mm pupil diameters were compared.

RESULTS

Fifteen (69%) eyes in the test group and 8 (36%) eyes in the control group achieved > or =20/25 uncorrected visual acuity 3 months after surgery, which was statistically significant (P<.05). The best spectacle-corrected visual acuity was > or =20/20 in 14 (63%) eyes in the test group and 10 (45%) eyes in the control group. The mean surgically induced astigmatism in the test group was 0.58+/-0.39 diopters (D) compared with 0.73+/-0.41 D in the control group. The change in corneal astigmatism from preoperative to 3 months after surgery was -0.17+/-0.32 D for the test group and 0.10+/-0.41 D for the control group, which was statistically significant (P<.05). The RMS value of trefoil aberrations increased, and all other aberrations decreased at 3 months after surgery in the test group. The RMS values of all corneal high order aberrations increased in the control group, with the increase in trefoil being statistically significant. The comparison of surgically induced high order aberrations between the two groups showed that corneal coma, trefoil, and secondary coma were significantly different.

CONCLUSIONS

Clear corneal tunnel phacoemulsification and IOL implantation guided by corneal topography can yield better visual acuity by reducing the pre-existing astigmatism and inducing less corneal aberrations than conventional temporal corneal tunnel phacoemulsification.