Comparison of Reading Speed after Bilateral Bifocal and Trifocal Intraocular Lens Implantation.

PURPOSE: To evaluate and compare visual acuity and reading speed for Korean language between a diffractive bifocal and trifocal intraocular lens (IOL) of the same material and haptic design. METHODS: We reviewed the medical records of the patients who had undergone bilateral cataract surgery with bifocal IOLs (AT LISA 801) on the both eyes (bifocal group) and trifocal IOLs (AT LISA tri 839 MP, trifocal group). The main outcome measures were the uncorrected distance, intermediate, and near visual acuity (uncorrected distance visual acuity [UCDVA], uncorrected intermediate visual acuity [UCIVA], and uncorrected near visual acuity [UCNVA]) and corrected distance, near, and distance-corrected intermediate visual acuity (corrected distance visual acuity [CDVA], corrected near visual acuity [CNVA], and distance-corrected intermediate visual acuity [DCIVA]) at last postoperative follow-up month. Reading speeds for Korean language were measured to check near visual function. RESULTS: Fourteen eyes (7 patients) were included in the bifocal group and 32 eyes of 16 patients in the trifocal group. There were no statistical differences between the two groups with respect to UCDVA, UCNVA, CDVA, and CNVA. However, UCIVA (0.35 vs. 0.22 logarithm of the minimum angle of resolution [logMAR], p < 0.01) and DCIVA (0.34 vs. 0.20 logMAR, p < 0.01) were significantly better in the trifocal group than in the bifocal group. The mean reading speed for logMAR 0.5 optotype (point 10) was 86.50 words per minute (wpm) in the bifocal group and 81.48 wpm in the trifocal group without a significant difference (p = 0.70). CONCLUSIONS: Trifocal IOLs provided the same level of distance and near visual acuity and reading speed as that of bifocal IOLs with better intermediate visual acuity.

Comparison of Ocular Biometry Using New Swept-source Optical Coherence Tomography-based Optical Biometer with Other Devices.

PURPOSE: To evaluate the agreement between optical biometry with swept-source optical coherence tomography-based optical biometry (IOLMaster 700) and other devices. METHODS: A total of 137 eyes (78 patients) with cataracts were included in this retrospective study. Axial length (AL), anterior chamber depth (ACD), keratometry, and white-to-white (WTW) distance measured using IOLMaster 700 were compared with results for the following five different biometers: IOLMaster 500, A-scan, automated refractor, manual keratometry, and Galilei G4. Differences and correlations among the devices were assessed using the Bland-Altman plot and intraclass correlation coefficient (ICC). RESULTS: For AL values, the IOLMaster 700, IOLMaster 500, and A-scan measurements showed excellent agreement (all ICC >0.99). For ACD values, ICC of IOLMaster 700 and Galilei G4 was 0.965 but A-scan was poorly correlated with either IOLMaster 700 or Galilei G4. The ICCs of IOLMaster 700 and other devices were all greater than 0.9 for average keratometry, but those of the mean cylinder keratometry were all between 0.7 and 0.8. The mean difference in the WTW distance between the IOLMaster 700 and Galilei G4 was 0.029 mm, but the ICC was 0.525. AL measurements were not possible for 10 eyes with the IOLMaster 500 but were obtained in all eyes with the IOLMaster 700. CONCLUSIONS: In clinical practice, AL, ACD, and average keratometry values of IOLMaster 700 can be used interchangeably with those of the other devices tested. However, the ACD value between IOLMaster 700 and A-scan or the WTW distance between IOLMaster 700 and Galilei G4 are not interchangeable because of clinical and statistical differences in measurements between the devices.

Korean Version Self-testing Application for Reading Speed.

PURPOSE: This study introduces a reading chart application for the iPad tablet in the Korean language and investigates the reading speed in a normal-sighted population according to age group. METHODS: Sixty-three Korean sentences were selected from textbooks for second grade elementary school students. A commonly used typeface in everyday printed material, "BatangChe," was used. Letter size was presented in logarithm of the minimum angle of resolution (logMAR) 0.0 to 1.0 at 0.1 logMAR steps at a reading distance of 40 cm. A third generation retina display iPad was used to present the chart, and the sentences were presented randomly for each size of letter. The subjects repeated the test silently (reading only) and out loud (reading and speaking) to prevent them from skipping reading words. Pilot testing followed in 65 normal vision adults under 60 years of age. RESULTS: The mean reading only speed for logMAR 0.5 optotype (point 10) was 121.1 ± 47.2 words per minute (wpm) for people in their 20s (n=21), 116.5 ± 38.3 in their 30s (n=27), 93.8 ± 12.6 in their 40s (n=9), and 56.5 ± 42.7 (n=8) in their 50s. There was a significant correlation between age and reading and speaking speed (r=-0.48, p<0.001). The mean reading only speed for logMAR 0.5 optotype (point 10) was 202.3 ± 88.4 wpm and the mean reading and speaking speed was 129.7 ± 25.9 wpm, with significantly different (p<0.001). CONCLUSIONS: This Korean reading chart application could present a new standard when checking reading speed according to age groups.

Possible Risk Factors and Clinical Effects of Opaque Bubble Layer in Small Incision Lenticule Extraction (SMILE).

PURPOSE: To report the development of an opaque bubble layer (OBL) during small incision lenticule extraction (SMILE) and analyze its potential risk factors and the clinical outcome. METHODS: A retrospective review of medical records was performed. The patients were divided into two groups in terms of OBL area following a posterior lenticule cut: OBL less than 5% of cornea and OBL greater than 5% of cornea. Preoperative parameters and clinical outcomes were compared. The association between amount of OBL and the various parameters was determined using a correlation analysis. RESULTS: The study included 208 myopic eyes (106 patients). The incidence of OBL was 51.82% (108 eyes) and mean OBL area was 3.06% ± 4.62%. The OBL greater than 5% group (48 eyes, 23.08%) had a thicker cornea, a thinner lenticule, and a longer operation time than the OBL less than 5% group (160 eyes, 72.92%). Visual acuity, efficacy, and safety were similar between groups except for a slightly lower predictability value for the OBL greater than 5% group. The amount of OBL area presented a quantitative association with corneal thickness, lenticule thickness, and the relative vertical position of the posterior lenticular surface. Flap tear was observed in 8 eyes (3.84%), at which an extensive amount of OBL (9.76% ± 7.02%) developed. CONCLUSIONS: Eyes with a thicker cornea or a thinner lenticule are more likely to develop OBL during SMILE. The OBL does not affect the overall clinical outcome. In eyes with extensive OBL, there is a higher incidence of flap tear and a lower predictability value. [J Refract Surg. 2017;33(1):24-29.].

Possible risk factors and clinical effects of an opaque bubble layer created with femtosecond laser-assisted laser in situ keratomileusis.

PURPOSE: To report the risk factors and clinical effects of an opaque bubble layer (OBL) during creation of a laser in situ keratomileusis (LASIK) flap with the Visumax 500 kHz femtosecond laser. SETTING: HanGil Eye Hospital, Incheon, South Korea. DESIGN: Retrospective comparative study. METHODS: Visual acuity, manifest refraction, intraocular pressure, corneal curvature, corneal thickness, and optical quality were evaluated. To prove a previous hypothesis that the harder a surgeon applanates during flap creation (hard-docking technique), the higher the incidence of OBL, the area of the meniscus on the cornea to which pressure was applied by the patient interface was calculated. Eyes were separated into 2 groups; that is, OBL-occurrence group and OBL-free group. Clinical outcomes in the 2 groups were compared to measure the risk factors and clinical effects of an OBL. RESULTS: The study included 827 myopic eyes. The incidence of OBL was 5.0% (41 eyes). The mean flat keratometry was steeper and the preoperative cornea thicker in the OBL-occurrence group. The OBL-occurrence group had harder applanation (ie, a larger area of meniscus) than the OBL-free group. The incidence of OBL was higher in the hard-docking technique. Clinical outcomes, including refractive error, visual acuity, and optical quality, in the 2 groups were not statistically significantly different 1 month after LASIK. CONCLUSIONS: The incidence of OBL was 5.0%. A steep, thick cornea and a hard-docking technique could be risk factors for an OBL. The OBL did not appear to affect optical quality or visual outcomes. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

The recovery of optical quality after laser vision correction.

PURPOSE: To evaluate the optical quality after laser in situ keratomileusis (LASIK) or serial photorefractive keratectomy (PRK) using a double-pass system and to follow the recovery of optical quality after laser vision correction. METHODS: This study measured the visual acuity, manifest refraction and optical quality before and one day, one week, one month, and three months after laser vision correction. Optical quality parameters including the modulation transfer function, Strehl ratio and intraocular scattering were evaluated with a double-pass system. RESULTS: This study included 51 eyes that underwent LASIK and 57 that underwent PRK. The optical quality three months post-surgery did not differ significantly between these laser vision correction techniques. Furthermore, the preoperative and postoperative optical quality did not differ significantly in either group. Optical quality recovered within one week after LASIK but took between one and three months to recover after PRK. The optical quality of patients in the PRK group seemed to recover slightly more slowly than their uncorrected distance visual acuity. CONCLUSIONS: Optical quality recovers to the preoperative level after laser vision correction, so laser vision correction is efficacious for correcting myopia. The double-pass system is a useful tool for clinical assessment of optical quality.