Regional comparison of preoperative biometry for cataract surgery between two domestic institutions.

PURPOSE: Regional variations of the preoperative biometry can affect the refractive accuracy of cataract surgery. We aimed to compare the preoperative biometric data for cataract surgery between two domestic institutions. METHODS: We retrospectively reviewed the preoperative biometric data of 673 consecutive eyes undergoing standard cataract surgery at Miyata Eye Hospital (Miyazaki; M group) and Kitasato University Hospital (Kanagawa; K group), and compared these data between the two groups. RESULTS: We found significant differences in the mean keratometric readings (44.39 ± 1.56 D vs. 44.09 ± 1.74 D) (unpaired t test, p = 0.034), the anterior chamber depth (3.14 ± 0.43 mm vs. 3.46 ± 0.62 mm) (p < 0.001), the axial length (23.98 ± 1.62 mm vs. 24.59 ± 1.82 mm) (p < 0.001), and the lens thickness (4.64 ± 0.48 mm vs. 4.37 ± 0.62 mm) (p < 0.001), in the M and K groups, respectively. Otherwise, we found no significant differences in corneal astigmatism (p = 0.104), or central corneal thickness (p = 0.480) between the two groups. For subgroup analysis, the prediction error (0.06 ± 0.47 D) in the M group was significantly more hyperopic than that (- 0.09 ± 0.54 D) in the K group (p = 0.006). CONCLUSIONS: There were significant differences in the mean keratometric readings, the anterior chamber depth, the axial length, and the lens thickness, by approximately 0.3 D, 0.3 mm, 0.6 mm, and 0.3 mm, respectively. Regional variations of the preoperative biometry did exist to some extent, and were not clinically negligible, in consideration of the precise IOL power calculation and the subsequent refractive accuracy of cataract surgery. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trial Registry (000037994).

Predictability of Intraocular Lens Power Calculation for Cataract with Keratoconus: A Multicenter Study.

This study was aimed to assess the predictability of intraocular lens (IOL) power calculation after cataract surgery for keratoconus. We retrospectively reviewed the clinical charts of 102 eyes of 71 consecutive keratoconic patients who developed cataract. We determined manifest spherical equivalent, prediction errors, and absolute errors, 1 month postoperatively. The achieved refraction was significantly more hyperopic than the targeted refraction, when keratometric readings were used (p = 0.001). At 1 month, 36% and 63% of the eyes were within ±0.5 and ±1.0 D, respectively, of the targeted correction. We found a significant correlation between the prediction error and the mean keratometry (Pearson correlation coefficient r =-0.545, p < 0.001). No vision-threatening complications occurred in any case. The achieved refraction was significantly more myopic than the targeted refraction, when total corneal refractive power was used (p = 0.013). Phacoemulsification with IOL implantation appeared to be safe and effective, and the accuracy was also good in mild keratoconus, but not in severe keratoconus. It should be noted that that a large amount of hyperopic shift occurred especially in advanced keratoconic patients, when keratometric readings were used for IOL power calculation, and that a slight, but significant, myopic shift occurred, when total corneal refractive power was used.

Effect of motion stimulation without changing binocular disparity on stereopsis in strabismus patients.

PURPOSE: To evaluate the effect of motion stimulation without changing binocular disparity on stereopsis in strabismic patients. METHODS: Static and moving stereopsis were measured in 120 normal children and 30 strabismic patients (9 esotropia, 14 exotropia, 7 intermittent exotropia). Using a portable game device (PSP; SONY, Japan), we created stereoscopic targets and produced stereopsis using a closed tube binocular viewing device. Stereoscopic disparity of targets was adjusted in 20 steps of 100 s each over a range from 2000 s to 100 s. In stereo testing using our apparatus, static test targets were used for static stereograms (SS), and test targets with clockwise planar rotation were used for moving stereograms (MS) without changing binocular disparity. RESULTS: All normal children were able to perceive stereopsis with stereoscopic disparity from 2000 s to 100 s, and were interested in our apparatus, more than the Titmus stereo tests. All esotropic patients failed both SS and MS. In the exotropic patients (14 exotropia and 17 intermittent exotropia patients), 19 (90.4%) passed the MS, and 13 (61.9%) passed the SS. CONCLUSION: The exotropic patient might be able to perceive the binocular stereopsis by moving stereogram that was created by adding clockwise planner rotation without changing the binocular disparity to the static stereopsis target.