Efficacy of Biometry Using Swept-source Optical Coherence Tomography for Posterior Chamber Phakic Intraocular Lens Implantation

Purpose@#The proper implantable collamer lens (ICL) size affects ICL stability. This study compared device efficacy using white-to-white diameter (WTW) measurements with Orbscan II and IOL Master 700. @*Methods@#We retrospectively studied 90 eyes (45 patients) who underwent toric ICL implantation from January 2019 to February 2020 and were followed for 1 year. The correlation between WTW and anterior chamber depth (ACD) for each measuring device was analyzed. @*Results@#The mean WTW measured by IOL Master 700 and Orbscan II was 12.2 ± 0.3 and 11.6 ± 0.3 mm, respectively, while the mean ACD was 3.28 ± 0.16 and 3.20 ± 0.15 mm. The WTW and ACD measured with IOL Master 700 averaged 0.57 ± 0.12 and 0.08 ± 0.04 mm larger than with Orbscan II. The differences were significant and the regression analysis had high correlations (R2 = 0.875 and R2 = 0.913, respectively; both p < 0.001). @*Conclusions@#WTW measured by the IOL Master 700 can be used as a reference either alone or together with the Orbscan II value to determine ICL size.

Visual Function after Multifocal Intraocular Lens Insertion in a Heterozygous Granular Corneal Dystrophy Type 2 Patient: Case Report

Purpose@#A patient with heterozygous granular corneal dystrophy type 2 (GCD2) underwent phacoemulsification with multifocal intraocular lens insertion, and complained of visual discomfort. We investigated the cause of the discomfort and visual function in this case.Case summary: A 59-year-old woman with granular opacity had slit lamp photographs taken 5 years earlier. Two years later, she underwent phacoemulsification with multifocal intraocular lens (Trifocal AT Lisa tri toric 839MP®, Carl Zeiss Meditec AG, Inc., Jena, Germany) insertion in both eyes at a local clinic. She felt very uncomfortable after the surgery, but the granular and lattice opacities due to GCD2 of her corneas remained stationary for 5 years. Her visual acuity decreased from preoperatively (preoperative: right 0.5, left 0.6; last visit: right 0.3, left 0.4). Her contrast sensitivity was also decreased and the total higher order aberration was increased (right 1.590 μm, left 1.194 μm), compared to normal range. @*Conclusions@#Multifocal intraocular lens insertion in cataract surgery can lead to severe declines in contrast sensitivity and visual acuity and increased higher-order aberration in a GCD2 patient. It may not be advisable to use multifocal intraocular lenses in a GCD2 patient.

Contrast Sensitivity Changes after Phototherapeutic Keratectomy in Heterozygote Granular Corneal Dystrophy Type 2

Purpose@#Contrast sensitivity, the ability to distinguish the relative difference in luminance of an object from its surrounding or adjacent objects, is a useful measure of visual function. In granular corneal dystrophy type 2 (GCD2), opacity of the corneal stroma causes deterioration in visual function. We compared the contrast sensitivity of GCD2 patients before and after phototherapeutic keratectomy (PTK) to evaluate the perioperative visual function in these patients. @*Methods@#This study included 22 eyes of heterozygote GCD2 patients. The visual acuity and contrast sensitivity were measured before and after PTK. The contrast sensitivity was measured in mesopic and photopic background luminances, with glare (G) levels of 0-2 (G0, G1, and G2, respectively) and spatial frequencies at 1.5, 3, 6, 12, and 18 cycles per degree (cpd). @*Results@#The contrast sensitivity increased after PTK at 1.5 and 3 cpd in mesopic and photopic conditions with G0-2 glare (p < 0.05). At 6 cpd, the contrast sensitivity increased in the mesopic condition with G1 glare, and in the photopic condition with G0-2 glare (p < 0.05). However, there was no change in contrast sensitivity at any glare level at 12 and 18 cpd after PTK. @*Conclusions@#In GCD2 patients, the contrast sensitivity increased significantly after PTK. The vision of GCD2 patients, which is decreased due to corneal opacity, is improved after PTK.

Intraocular Lens Power Calculation Using Shammas-PL Formula after Laser In-situ Keratomileusis

Purpose@#To calculate the intraocular lens (IOL) power using the Shammas-PL formula after laser in-situ keratomileusis (LASIK). @*Methods@#Forty-one eyes of 29 patients that had undergone cataract surgery from September 2018 to September 2019 after LASIK were enrolled in this study. A preoperative AL-Scan® (Nidek Co., Gamagori, Japan) was used to measure the axial length, anterior chamber depth, and corneal curvature. An IOL power calculation was performed using the Shammas-PL (post LASIK) formula. Mean absolute error (MAE) and mean arithmetic error (MARE) were calculated using preoperative manifest refraction and postoperative manifest refraction. @*Results@#Of the 41 eyes, 15 eyes (36.6%) were relatively hyperopic-shifted after surgery compared to the predicted refractive error before surgery, 25 eyes (61%) showed a relative myopic shift, and one eye (2.4%) showed no change with respect to the previous refractive predicted error. Refractive errors before cataract surgery were not related to myopic, emmetropic, or hyperopic shifting after surgery (p > 0.05). @*Conclusions@#When cataract surgery using the Shammas-PL formula was performed after LASIK, myopic shifting was more common than hyperopic shifting. The MAE was greater in myopic-shifted cases than that of hyperopic-shifted cases. Thus, it is better to determine IOL power toward the hyperopic side than the target refractive prediction.

Short-term Comparison of Refractive Errors between Two Different Age Groups after LASEK for Moderate Myopia

Purpose@#To investigate the safety of laser epithelial keratomileusis (LASEK) by drawing a comparison between two groups divided according to age (18-19 vs. 20-21 years old). @*Methods@#The study was conducted as a retrospective analysis including 339 patients (678 eyes) who underwent LASEK between January 2017 and April 2020. Patients were divided by age group, group I (18-19 years old) and group II (20-21 years old). The objectives of the study included determination of visual acuity and refractive errors before and at 1, 3, and 6 months after the procedure. @*Results@#The preoperative mean spherical equivalents (SEs) were -4.73 ± 0.88 diopters (D) in group I and -4.58 ± 0.87 D in group II (p = 0.34). At 1 month postoperatively, mean SEs were 0.32 ± 0.46 D in group I and 0.26 ± 0.59 D in group II (p = 0.18). At 3 months postoperatively, the mean SEs were 0.30 ± 0.47 D in group I and 0.28 ± 0.50 D in group II (p = 0.67). At 6 months postoperatively, the mean SEs were 0.15 ± 0.47 D in group I and 0.14 ± 0.50 D in group II (p = 0.89). There were no significant differences in postoperative best corrected visual acuity between group I and group II at 1, 3, or 6 months (p = 0.20, p = 0.13, and p = 0.11, respectively). @*Conclusions@#There were no significant differences in postoperative mean SE or safety of LASEK between moderate myopia patients 18-19 years old and those 20-21 years old.

Clinical Significance of Tear Film Osmolarity in Patients with Mild Dry Eye Syndrome

Purpose@#To seek Pearson correlations of tear film osmolarity measured by the I-PEN® (I-MED Pharma Inc., Dollard-des-Ormeaux, Canada) with Schirmer test result, tear break-up time, and Ocular Surface Disease Index score in patients with mild dry eye syndrome. @*Methods@#Patients with mild dry eye syndrome were divided into two groups according to Ocular Staining Score: group 1 (50 patients; 67 eyes) and group 2 (59 patients; 91 eyes), 90 patients and 158 eyes in total. The above mentioned correlations were derived. @*Results@#No significant correlations were observed between tear film osmolarity and Schirmer test result (r < -0.01, p = 0.97), tear break-up time (r = 0.05, p = 0.54), or Ocular Surface Disease Index score (r = 0.03, p = 0.76). When the two groups were compared, the Ocular Surface Disease Index score significantly differed between groups (p < 0.01), whereas the Schirmer test result (p = 0.31), tear break-up time (p = 0.11), and tear film osmolarity (p = 0.12) did not. @*Conclusions@#No significant correlations were found between tear film osmolarity and other dry eye indicators in patients with mild dry eye syndrome. The diagnostic utility of tear film osmolarity in patients with moderate dry eye syndrome is should be evaluated.

Clinical Significance of Tear Film Osmolarity in Patients with Mild Dry Eye Syndrome

Purpose@#To seek Pearson correlations of tear film osmolarity measured by the I-PEN® (I-MED Pharma Inc., Dollard-des-Ormeaux, Canada) with Schirmer test result, tear break-up time, and Ocular Surface Disease Index score in patients with mild dry eye syndrome. @*Methods@#Patients with mild dry eye syndrome were divided into two groups according to Ocular Staining Score: group 1 (50 patients; 67 eyes) and group 2 (59 patients; 91 eyes), 90 patients and 158 eyes in total. The above mentioned correlations were derived. @*Results@#No significant correlations were observed between tear film osmolarity and Schirmer test result (r < -0.01, p = 0.97), tear break-up time (r = 0.05, p = 0.54), or Ocular Surface Disease Index score (r = 0.03, p = 0.76). When the two groups were compared, the Ocular Surface Disease Index score significantly differed between groups (p < 0.01), whereas the Schirmer test result (p = 0.31), tear break-up time (p = 0.11), and tear film osmolarity (p = 0.12) did not. @*Conclusions@#No significant correlations were found between tear film osmolarity and other dry eye indicators in patients with mild dry eye syndrome. The diagnostic utility of tear film osmolarity in patients with moderate dry eye syndrome is should be evaluated.

Central Toxic Keratopathy after Femtosecond Laser in-situ Keratomileusis

Purpose@#To report a case of central toxic keratopathy after femtosecond laser in-situ keratomileusis (LASIK).Case summary: A 26-year-old male developed diffuse lamellar keratitis bilaterally on day 2 after femtosecond LASIK. He was applying topical steroid frequently, while also using topical antibiotics. On day 6 after LASIK, slit-lamp biomicroscopy showed a thick central corneal opacity on the right eye so a flap irrigation was performed. He was then treated with systemic methylprednisolone. A corneal epithelial crack and stromal striae were noted by slit-lamp biomicroscopy on postoperative day 10. Four weeks after LASIK, the refractive error was +4.25 Dsph = -1.25 Dcyl Axis 80°. He was treated with topical steroid, topical antibiotics, and oral doxycycline until eight weeks after LASIK. Eight weeks after LASIK, the patient was observed without treatment. The central corneal thickness recovered from 488 μm at eight weeks to 540 μm, and the refractive error was +1.25 Dsph = -0.75 Dcyl Axis 85° at postoperative 72 weeks. The central corneal opacity also recovered. @*Conclusions@#Because femtosecond LASIK may result in a combination of diffuse lamellar keratitis and central toxic keratopathy, the clinical characteristics and natural course of both diseases should be understood and timely treatment should be available.

Comparison of Perioperative Contrast Sensitivity between Laser in situ Keratomileusis and Small-incision Lenticule Extraction

Purpose@#To compare contrast sensitivity before and after surgery in patients who underwent laser in situ keratomileusis (LASIK)and small-incision lenticule extraction (SMILE). @*Methods@#From February 2019 to April 2019, 20 patients who underwent LASIK, and 21 who underwent SMILE, were comparedbefore, one day, one week, and one month after surgery. @*Results@#On postoperative day (POD) 1, contrast sensitivity was better in the LASIK group than in the SMILE group under all conditionsfor 1.6, 1, and 0.64 cycles per degree (cpd). One week after surgery, the contrast sensitivity of the LASIK group was betterthan that of the SMILE group under photopic conditions with glare for 1.6, 1, and 0.64 cpd, under photopic conditions withoutglare for 1 and 0.64 cpd, and under all scotopic conditions for 2.5, 1.6, and 0.64 cpd (p< 0.05). There was no significant differencebetween the two groups, except under the scotopic conditions without glare for 0.64 cpd at one month after surgery. In theLASIK group, the contrast sensitivity was best at one week after surgery. The SMILE group showed the poorest contrast sensitivityon POD 1, but this gradually improved. @*Conclusions@#The LASIK group had better contrast sensitivity on one day and one week after surgery than the SMILE group, butthere was no significant difference at one month after surgery. In the LASIK group, the contrast sensitivity was best at one weekafter surgery. In the SMILE group, the contrast sensitivity was worst on POD 1.

Refractive Power Outcomes with an Intraocular Lens with 0.25-diopter Intervals

Purpose@#The Eyelike K-flex Aspheric® (Koryoeyetech, Seoul, Korea) is manufactured in 0.25-diopter (D) intervals, which allows the target refractive error after surgery to be achieved. We here evaluate the refractive power outcomes. @*Methods@#We retrospectively studied 95 eyes of 72 patients who underwent cataract surgery with implantation of the Eyelike K-flex Aspheric®. Refractive error was measured at 1 and 2 months postoperatively (33 eyes of 27 patients) and compared to that of patients fitted with 0.50-D-interval lenses (62 eyes of 49 patients). @*Results@#At 1 month postoperatively, the mean absolute error between the spherical equivalent and planned value was 0.33 ± 0.28 and 0.41 ± 0.39 D in the 0.25- and 0.50 D-interval lens groups, respectively (p = 0.318). At 2 months postoperatively, the respective values were 0.21 ± 0.15 and 0.34 ± 0.29 D (p = 0.009). @*Conclusions@#The Eyelike K-flex Aspheric® shows excellent refractive predictability; use of 0.25-D-interval intraocular lenses close to the target refractive power allows the desired spherical equivalent to be achieved.

Accuracy of Intraocular Lens Power Calculations Based on Total and Standard Keratometry

Purpose@#To compare the accuracy of standard and total keratometry data obtained using the Barrett Universal II and Barrett Toric Calculator. @*Methods@#In total, 111 eyes of 111 patients who visited our hospital for cataract surgery from February 2019 to September 2019 were included in this study. Total keratometry and standard keratometry data were obtained using the Barrett Universal II and the Barrett Toric Calculator; mean absolute errors were derived by using preoperative IOL Master 700® (Carl Zeiss Meditech AG, Jena, Germany) data and 2-month postoperative manifest refraction data. The mean absolute errors of the two methods were compared in terms of a posterior corneal astigmatism greater than 0.3 diopter (D) in patients fitted with Toric intraocular lenses. @*Results@#Using the Barrett Universal II formula, the mean absolute error spherical equivalent difference between total keratometry and standard keratometry was 0.021 ± 0.102 D (p = 0.65) when the Barrett Toric Calculator was used. The mean absolute error differences between the two methods were 0.015 ± 0.121 D for the spherical equivalent (p = 0.80) and 0.005 ± 0.870 D for the cylinder measurement (p = 0.94). In terms of a posterior corneal astigmatism greater than 0.3 D, the mean absolute error spherical equivalent and cylinder measurement differences were -0.020 ± 0.107 D (p = 0.70) and -0.023 ± 0.055 D (p = 0.50) in patients fitted with Toric intraocular lenses. @*Conclusions@#The total keratometry method, which directly measures posterior corneal curvature, yields data comparable to those of the standard keratometry method. When the posterior corneal astigmatism was greater than 0.3 D, we found no significant difference between the total keratometry and standard keratometry data of patients fitted with Toric intraocular lenses.

Refractive Power Outcomes with an Intraocular Lens with 0.25-diopter Intervals

Purpose@#The Eyelike K-flex Aspheric® (Koryoeyetech, Seoul, Korea) is manufactured in 0.25-diopter (D) intervals, which allows the target refractive error after surgery to be achieved. We here evaluate the refractive power outcomes. @*Methods@#We retrospectively studied 95 eyes of 72 patients who underwent cataract surgery with implantation of the Eyelike K-flex Aspheric®. Refractive error was measured at 1 and 2 months postoperatively (33 eyes of 27 patients) and compared to that of patients fitted with 0.50-D-interval lenses (62 eyes of 49 patients). @*Results@#At 1 month postoperatively, the mean absolute error between the spherical equivalent and planned value was 0.33 ± 0.28 and 0.41 ± 0.39 D in the 0.25- and 0.50 D-interval lens groups, respectively (p = 0.318). At 2 months postoperatively, the respective values were 0.21 ± 0.15 and 0.34 ± 0.29 D (p = 0.009). @*Conclusions@#The Eyelike K-flex Aspheric® shows excellent refractive predictability; use of 0.25-D-interval intraocular lenses close to the target refractive power allows the desired spherical equivalent to be achieved.

Accuracy of Intraocular Lens Power Calculations Based on Total and Standard Keratometry

Purpose@#To compare the accuracy of standard and total keratometry data obtained using the Barrett Universal II and Barrett Toric Calculator. @*Methods@#In total, 111 eyes of 111 patients who visited our hospital for cataract surgery from February 2019 to September 2019 were included in this study. Total keratometry and standard keratometry data were obtained using the Barrett Universal II and the Barrett Toric Calculator; mean absolute errors were derived by using preoperative IOL Master 700® (Carl Zeiss Meditech AG, Jena, Germany) data and 2-month postoperative manifest refraction data. The mean absolute errors of the two methods were compared in terms of a posterior corneal astigmatism greater than 0.3 diopter (D) in patients fitted with Toric intraocular lenses. @*Results@#Using the Barrett Universal II formula, the mean absolute error spherical equivalent difference between total keratometry and standard keratometry was 0.021 ± 0.102 D (p = 0.65) when the Barrett Toric Calculator was used. The mean absolute error differences between the two methods were 0.015 ± 0.121 D for the spherical equivalent (p = 0.80) and 0.005 ± 0.870 D for the cylinder measurement (p = 0.94). In terms of a posterior corneal astigmatism greater than 0.3 D, the mean absolute error spherical equivalent and cylinder measurement differences were -0.020 ± 0.107 D (p = 0.70) and -0.023 ± 0.055 D (p = 0.50) in patients fitted with Toric intraocular lenses. @*Conclusions@#The total keratometry method, which directly measures posterior corneal curvature, yields data comparable to those of the standard keratometry method. When the posterior corneal astigmatism was greater than 0.3 D, we found no significant difference between the total keratometry and standard keratometry data of patients fitted with Toric intraocular lenses.

A Case of Clozapine-induced Corneal and Lenticular Pigmentation

PURPOSE: To report a case of corneal and lenticular pigmentation after prolonged clozapine therapy. CASE SUMMARY: A 56-year-old male visited our hospital with a progressive decline in vision that affected both eyes. He had a history of schizophrenia. He was being treated with 200 mg clozapine and 1 mg lorazepam daily, and had been treated with clozapine for 5 years. At the first visit, his best-corrected-visual acuity was 20/32 in both eyes. Slit lamp examination of the corneas showed bright, fine, grayish-brown deposits on the endothelium, and on dilation, bilateral central stellate opacity of the anterior portion of the lens capsule was revealed. CONCLUSIONS: Clozapine may induce corneal and lenticular pigmentation and thus may lead to a decline in vision. Patients on long-term clozapine therapy should be considered for regular ophthalmic review.

Role of kaempferol to increase bioavailability and pharmacokinetics of nifedipine in rats / 中国天然药物

Herein, the purpose of this study is to evaluate the effects of kaempferol on bioavailability and pharmacokinetics of nifedipine and its metabolite dehydronifedipine in rats. The experimental design is based on with or without kaempferol in the oral and intravenous administration of nifedipine in rats. Moreover, the pharmacokinetic parameters including nifedipine and dehydronifedipine were evaluated in rats.The in vitro studies ofkaempferol were investigated on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity. Kaempferol reduced a 50% inhibitory concentration (IC) of 8.6 μmol·L on CYP3A4 enzyme activity. Moreover, kaempferol clearly improved the cell internalization of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. Depending on increased concentrations of kaempferol, the areas under the plasma concentration-time curve (AUC) and the peak concentration (C) of nifedipine were increased after oral and intravenous administration. Moreover, the absolute bioavailability (AB) and relative bioavailability (RB) of nifedipine in the presence of kaempferol was significantly higher than those of the control group after oral and intravenous administration. Improvement of bioavailability of nifedipine by kaempferol may be mainly because of the inhibition of the P-gp-mediated efflux transporter in the small intestine and CYP3A4-mediated metabolism in the small intestine or liver, or both.

Repositioning of a Free Cap after Laser-assisted in situ Keratomileusis

PURPOSE: To report a case of irregular astigmatism caused by a free flap during laser-assisted in situ keratomileusis (LASIK) surgery that was treated with a flap rotation based on postoperative topography. CASE SUMMARY: A 21-year-old female underwent LASIK, which was complicated by a free cap on her right eye. Because the gentian violet markings were no longer present, the exact orientation of the cap was unknown. At 3 months after surgery, the astigmatism of the right eye was −3.00 diopters (D) with an uncorrected visual acuity (UCVA) of 0.4, and the astigmatism of the left eye was −0.75 D with an UCVA of 1.0. The corneal topography was analyzed in order to return to the existing position. Free cap repositioning was performed and irregular astigmatism was corrected to improve the UCVA to 1.0. CONCLUSIONS: If the preoperative markings cannot be identified on a free flap during LASIK, secondary postoperative corneal topographic analysis can be performed to restore the corneal free flap to its original position to minimize astigmatism with good visual outcomes.

Clinical Results and Optical Quality of Diffractive Multifocal Intraocular Lens

PURPOSE: To compare postoperative clinical outcomes, optical quality, and patient satisfaction between two types of diffractive multifocal intraocular lens (IOL, Acri Lisa 366D and Acrysof ReSTOR +3.00 D). METHODS: In a total of 68 eyes, one of two diffractive multifocal IOL (Acri Lisa 366D and Acrysof ReSTOR +3.00 D) was implanted after cataract extraction. Visual acuity was measured postoperatively at one week, 1 month, and 6 months. Contrast sensitivity, wavefront aberration, and visual function were determined via questionnaire at postoperative 1 month. RESULTS: Intermediate visual acuity of Acri Lisa 366D and Acrysof ReSTOR at 6 months were 0.31 +/- 0.14, and 0.24 +/- 0.11 (log MAR), respectively. At 6 months, near and distant visual acuity results showed no significant differences between the two groups. The photopic contrast sensitivity of Acri Lisa 366D at 6 cycles/degree was 55.36 +/- 7.40 and showed significant differences with Acrysof ReSTOR (47.25 +/- 9.67). The mesopic contrast sensitivity values of Acri Lisa 366D and Acrysof ReSTOR were 40.26 +/- 11.38 and 28.97 +/- 10.45, respectively, and the spherical aberration values were 0.037 +/- 0.039 microm and 0.105 +/- 0.066 microm. The spherical aberration of Acri Lisa 366D was significantly lower than that of Acrysof ReSTOR. Total and high order aberration, coma, and trefoil show no significant differences between the two groups. CONCLUSIONS: The Acri Lisa 366D multifocal IOL showed better contrast sensitivity and spherical aberration compared to Acrysof ReSTOR multifocal IOL, which had an effective intermediate visual acuity.

Higher-Order Aberrations and Visual Acuity with Wavefront-Guided and Wavefront-Optimized Ablation in Laser Keratorefractive Surgery

PURPOSE: To compare higher-order aberrations (HOAs) and visual acuity after wavefront-guided and wavefront-optimized laser keratorefractive surgery. METHODS: This retrospective study consisted of consecutive cases of eyes that underwent wavefront-guided (VISX S4 CustomVue(R)) or wavefront-optimized (WaveLight(R) EX500) laser assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction spherical equivalent (MRSE), and preoperative and 3 month postoperative HOAs were compared. RESULTS: There were no statistical differences in UCVA, BCVA, MRSE, or total HOAs in either the LASIK and PRK groups (all p > 0.05). Induced amount of spherical aberration (SA) was significantly lower in the wavefront-optimized LASIK and PRK than wavefront-guided LASIK and PRK. CONCLUSIONS: In laser keratorefractive surgery, wavefront-guided and wavefront-optimized platforms produced equivalent visual outcomes and no differences in total HOAs. However, the wavefront-optimized platform caused less spherical aberration 3 months after operation.

Accuracy of Intraocular Lens Power Calculations According to Corneal Curvature in Short Eyes

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculations between Hoffer Q and other formulas according to corneal curvature by comparing the results of cataract surgery and calculation of chosen formulas in short axial lengths. METHODS: We performed a retrospective analysis of patients who underwent cataract surgery from January 1st, 2012 to June 12th, 2012. The patients were selected if their axial length was below 23.00 mm and 77 patients (90 eyes) were included in the present study. The patients were divided into 2 groups according to mean corneal curvature below 44.0 D and over 45.0 D. IOL power was calculated using the Hoffer Q and SRK II, SRK-T and Holladay I formulas and the error between the calculations and refractive outcome of cataract surgery were measured. The accuracy of each formula was evaluated by comparing the error between the 2 groups. RESULTS: Hoffer Q formula showed a higher predictive accuracy than other formulas regardless of corneal curvature in eyes with short axial lengths (p < 0.001, p = 0.023). Particularly, SRK II, SRK-T and Holladay I showed a lower predictive accuracy in eyes with flat corneal curvature than Hoffer Q (p < 0.001, p = 0.215). CONCLUSIONS: In eyes with short axial lengths, preoperative predicted IOL power calculations showed better accuracy with Hoffer Q formula than SRK II, SRK-T and Holladay I formulas. SRK II, SRK-T and Holladay I formulas showed a lower predictive accuracy in flat corneal curvature eyes than steep corneal curvature eyes with short axial lengths. We hypothesize that SRK II, SRK-T and Holladay I tend to underestimate effective lens position in eyes with short axial lengths indicating Hoffer Q formula is more accurate.

Accuracy of Ocular Biometry and Postoperative Refraction in Cataract Patients with AL-Scan(R)

PURPOSE: To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict postoperative refractions of AL-Scan(R), IOL master(R), and ultrasound. METHODS: A total of 40 eyes in 30 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured by 2 types of partial coherence interferometry (AL-Scan(R) and IOL master(R)) and ultrasound. The SRK/T formula was used to calculate IOL power, and the predictive error which subtracts predictive refraction from postoperative refraction was compared among the ocular biometry devices. RESULTS: Axial lengths were 23.08 +/- 0.62 mm, 23.09 +/- 0.62 mm, and 22.99 +/- 0.62 mm measured by AL scan(R), IOL master(R), and ultrasound, respectively. Axial length measured by ultrasound was statistically significantly shorter than AL scan(R) and IOL master(R) (p < 0.001, p < 0.001, respectively). The anterior chamber depth and keratometry were 3.11 +/- 0.06 mm and 44.82 +/- 1.34 D measured by AL scan(R), and 3.13 +/- 0.06 mm and 44.85 +/- 1.26 D measured by IOL master(R), respectively. The differences of anterior chamber depth and keratometry between the 2 devices were not statistically significant (p = 0.226, p = 0.331, respectively). The mean absolute prediction errors were 0.44 +/- 0.35 D, 0.40 +/- 0.34 D, and 0.39 +/- 0.30 D in AL-Scan(R), IOL master(R) and ultrasound, respectively, and were not statistically significantly different (p = 0.843, p = 0.847, p = 1.000, respectively). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using AL-Scan(R) were as accurate as IOL master(R) and ultrasound.