Akeno Tamaoki

Evaluation of Axial Length Measurement of the Eye Using Partial Coherence Interferometry and Ultrasound in Cases of Macular Disease

PURPOSE The present study evaluated the accuracy of using partial coherence interferometry (PCI) and ultrasound (US) to measure axial length in eyes with macular disease, the nature of the double peak (DP) in PCI measurements, and the applicability of intraocular lens (IOL) power calculation. DESIGN Retrospective noncomparative case series. PARTICIPANTS We studied 132 eyes with macular edema, epiretinal membrane, and macular hole in 132 patients who underwent combined cataract and vitrectomy surgery. METHODS Axial length was measured using PCI and US. If a DP was observed in the PCI measurement, the posterior peak was used for the IOL calculation. The central retinal thickness (CRT) was measured using optical coherence tomography. MAIN OUTCOME MEASURES Measurements were made of the frequency of DP observation in PCI measurement and the postoperative refractive errors when either PCI or US measurements were applied. RESULTS A DP was observed in 25 (18.7%) of 132 eyes in the axial length measurement using PCI. There was a significant correlation between the interpeak distance and the CRT (P<0.001, r(2)=0.3869). The 6-month postoperative refractive errors in the DP and single peak (SP) groups were predicted correctly within +/-0.5 diopters in 56.0% (DP) and 61.7% (SP) of the cases and within +/-1.0 diopters in 92.0% (DP) and 92.2% (SP) of the cases. The accuracy of the axial length measurement was similar between PCI and US. CONCLUSIONS Our results suggest that the longer axial length of the DP observed in PCI represents retinal pigment epithelium. If a DP was observed in PCI measurement, application of the longer peak for the IOL calculation resulted in a refractive error similar to that in the SP group.

Intraocular lens power calculation in cases with posterior keratoconus.

Purpose To compare the calculation errors of intraocular lens (IOL) power in patients with posterior keratoconus and to determine which corneal refractive power is suitable for these calculations. Setting Chukyo Hospital, Nagoya, Japan. Design Retrospective case series. Methods This retrospective chart review was performed to identify eyes diagnosed with posterior keratoconus using anterior segment optical coherence tomography (AS‐OCT). The keratometry (K) values were measured using an autokeratometer and partial coherence interferometry (PCI) (IOLMaster). The AS‐OCT measured the total refractive corneal power and the anterior to posterior corneal curvature (A/P) ratio. Predicted refractive errors were calculated from K values based on the postoperative subjective refractive errors. Results The chart review of 4621 eyes found that 4 eyes of 4 patients (mean age 74.8 years ± 13.0 [SD]) were diagnosed with posterior keratoconus. The total refractive corneal power values were the smallest among all of the corneal refractive powers in all 4 eyes. The preoperative A/P ratio was 1.45 (Case 1), 1.26 (Case 2), 1.25 (Case 3), and 1.44 (Case 4). When the PCI measured K values were applied for the IOL power calculations, all of the eyes became hyperopic with postoperative refractive errors of +1.51 diopters (D) (Case 1), +0.34 D (Case 2), +0.97 D (Case 3), and +1.08 D (Case 4). When the total refractive corneal power values were applied, the errors were +0.10 D (Case 1), −0.18 D (Case 2), −0.61 D (Case 3), and −0.65 D (Case 4). Conclusion The real corneal power values that take both the anterior and posterior corneal curvatures into consideration should be applied for IOL power calculations in cases with posterior keratoconus. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Clinical and ex vivo laboratory comparison of the self-sealing properties and dimensional stability between the femtosecond laser and manual clear corneal incisions

To compare the self‐sealing features and dimensional stability between the femtosecond laser (FL) and manual knife corneal incision.

Impact of the anterior-posterior corneal radius ratio on intraocular lens power calculation errors

Purpose To evaluate the distribution of the anterior–posterior corneal radius ratio (AP ratio; anterior corneal radius/posterior corneal radius) in patients before cataract surgery, and investigate which parameters can affect this ratio. We also investigated the impact of the AP ratio on the intraocular lens (IOL) power calculation error in cataract surgery. Method A total of 501 eyes of 501 consecutive patients who had no history of corneal diseases and had undergone cataract surgery were enrolled in this study. The patients’ AP ratio was measured before surgery using anterior segment optical coherence tomography; using these data, we evaluated the correlation between the AP ratio and various parameters that can affect the corneal radius. For subgroup analyses, we investigated the correlation between the AP ratio and IOL power calculation error in 181 eyes of 181 patients. Stepwise multiple regression analysis was performed with the IOL power calculation errors of the SRK/T, Haigis, Holladay 1, and Hoffer Q formulas as the dependent variables and various parameters that can affect the postoperative IOL power calculation error as the independent variables. Results The mean AP ratio was 1.19±0.02, and it weakly correlated with corneal thickness, horizontal corneal diameter, and posterior corneal radius. The correlations between the AP ratio and IOL power calculation errors in the 4 calculation formulas were not statistically significant. Stepwise multiple regression analysis could not detect any significant parameters affecting this ratio. Conclusion The AP ratio has no major influence on IOL power calculation error in patients with any history of corneal disease.

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.

Early result on accommodative IOL implanted eye

調節が可能といわれている眼内レンズC & C Vision社CrystaLens AT-45®を挿入する機会を得た。AT-45®は、支持部への圧力で光学系が前房側に偏位することで調節するとしている。この眼内レンズを白内障以外に眼疾患を認めず、インフォームドコンセントで同意の得られた8例16眼(以下A群)に挿入し、術後3ヶ月までの結果について検討した。コントロールとして、従来型単焦点眼内レンズCanonstaar社AQ-110 NV®を挿入した15例30眼(以下B群)と比較した。遠見視力はA群、B群とも良好であった。片眼および両眼の遠見矯正下近見視力に統計学的な有意差はないが、加入度数において、有意差を認めた。また、A群の遠見矯正下近見視力は、有意差はないものの術後1ヶ月よりも3ヶ月の方が上がる傾向にあった。コントラスト感度をメニコン社CAT-2000®で測定した。A群とB群に有意差はなく、ほぼ同等の結果となった。A群とB群にアンケートをとった結果、B群よりA群の方が近くの見え方が良い結果となったが、A群では夜間の見にくさを訴える症例も多く認められた。RION社UX-03®でAT-45®の前房側への移動を観察したが、確認できなかった。多数のAT-45®挿入例について報告しているCummingらほど、近見視力に良い結果は得られなかった。AT-45®は従来型の単焦点眼内レンズと比較して劣ることはなかったが、調節力に関しては今後さらに他覚的な検討が必要であると思われた。また、Cummingらは、術後5ヶ月以上の近方視のトレーニングを推奨しており、長期の経過観察が必要と思われる。

Evaluation of measurement condition of pupil diameter with COLVERD PUPILLOMETER

Measurement of pupil diameter is now of much importance because of the spread of refractive surgery such as laser surgery and multifocal IOL implantation . We have investigated the measurement of pupil diameter by COLVERD PUPILLOMETER (OASYS, CP), which is useful for easy operation, and that by conventionally used IRISCORDER C-7364 (IC). The pupil diameter was measured under different illuminance and different distance. Further, the measurements were done with or without the rest eye covered. The pupil diameter measured by CP was larger than that by IC especially in the bright condition. Below 5 lux, however, no significant difference was observed between CP and IC. The pupil diameter of near vision was larger than that of far vision regardless of the illuminance. In the case of CP, the measurements were easily done if the rest eye covered using internal fixation light. As a result, it is possible to obtain the same diameter by CP in a semi-darkroom around 1 lux as under absolute dark condition. It is necessary to measure at a constant distance. If the distance is not clear, the measurement shoud be done under the rest eye covered.