Evaluation of efficacy of new lens nucleus fragmenting forceps in cataract surgery / Avaliação da eficácia de uma nova pinça fragmentadora de núcleo do cristalino para cirurgia de catarata

ABSTRACT Objective: To evaluate the efficacy of low-cost nucleus fragmenting forceps designed to reduce the use of ultrasound during phacoemulsification. Methods: A total of 60 pig eyes enucleated 10 hours before were placed in the microwave oven, at maximum power for 10 seconds, to form cataracts with hardness comparable to a grade IV nucleus in the Lens Opacities Classification System III. Cataract extraction was performed using the Centurion® phacoemulsifier (Alcon Laboratories, Geneve, Switzerland) and Leica M620 microscope. All eyes were submitted to the pre-chop technique dividing the nucleus into four parts. After the pre-chop, the quadrants in 30 eyes were phacoemulsified with the torsional mode and were fragmented in the remaining 30 eyes after the pre-chop was with the fragmentation forceps before torsional mode phacoemulsification. The device was calibrated for all eyes by applying the following parameters: 40% linear torsional phacoemulsification; intraocular pressure of 65 mmHg; the linear vacuum of 600 mmHg; aspiration flow of 40 ccs/minute. After each procedure, the following was recorded: cumulative dissipated energy; equivalent average torsional amplitude; equivalent average ultrasonic power; estimated aspirated fluid; ultrasound total time; and total aspiration time. Statistical analysis was performed using the Kruskal-Wallis test and the IBM Statistical Package for Social Sciences. The p-value <0.05 was considered statistically significant. Results: There was a statistically significant reduction favoring the use of the nucleus fragmenting forceps in all parameters, except for the average torsional amplitude. Conclusion: The use of the nucleus fragmenting forceps contributed to improving the efficacy of torsional phacoemulsification in enucleated pig eyes.

RESUMO Objetivo: Avaliar a eficácia de uma pinça fragmentadora de núcleo, de baixo custo, desenvolvida para reduzir o uso de ultrassom durante a emulsificação do núcleo. Métodos: Sessenta olhos de porco com 10 horas de enucleação foram colocados no forno de microondas, em potência máxima por 10 segundos, para a formação de catarata com dureza comparável à de um núcleo grau IV na Lens Opacities Classification System III. A extração da catarata foi realizada com o facoemulsificador Centurion® (Alcon Laboratories, Genebra, Suíça) e microscópio Leica M620. Todos os olhos foram submetidos a técnica de pre-chop, dividindo o núcleo em quatro partes. Em 30 olhos, após o pre-chop, foi feita a facoemulsificação dos quadrantes com o modo torsional e, nos outros 30 olhos, após o pre-chop, cada quadrante foi fragmentado com a pinça antes da facoemulsificação com o modo torsional. O aparelho foi calibrado para todos os olhos com os seguintes parâmetros: faco torsional linear 40%; pressão intraocular 65 mmHg; vácuo linear 600mmHg e fluxo de aspiração 40cc/minuto. Após cada procedimento, verificaram-se energia dissipada acumulada; média da amplitude do faco torsional; média equivalente do poder ultrassônico; líquido aspirado estimado; tempo total de ultrassom e tempo total de aspiração. A análise estatística foi realizada utilizando o teste de Kruskal-Wallis com o IBM Statistical Package for Social Sciences. Valor de p<0,05 foi considerado estatisticamente significante. Resultados: Houve redução estatisticamente significante em favor do uso da pinça fragmentadora de núcleo em todos os parâmetros, menos na média de amplitude do faco torsional. Conclusão: O uso da pinça fragmentadora de núcleo contribuiu para melhorar a eficácia do faco torsional em olhos de porco enucleados.

Paying attentions to advantages and disadvantages of intraocular femtosecond laser in cataract surgery / 中华实验眼科杂志

Requirements for cataract surgery have gradually increased from the original rehabilitation procedure to personalized refraction surgery.Femtosecond laser-assisted cataract surgery is being widely used because of its precision of incision,accuracy of capsule cutting and high efficiency of nuclear fracturing in recent year.Currently some operating systems of femtosecond laser-assisted cataract surgery include LenSx,Catalys,LenSAR and Victus,and they are different in the design of contact interfaces,video and operating bed and therefore present different working methods.Ophthalmologists should be aware of the differences of these operating systems and accurate assess the clinical findings of patients in order to consider the preciseness,accuracy,efficiency of incision,capsulorhexis and nucleus fragmentation to avoid the intraoperative and postoperative complications.

A randomized controlled clinical study on reverse-chopper prechop technique with phaco-and-chop technique for high myopia associated with hard nucleus cataract / 中华实验眼科杂志

Background The innovation of pre-chop technique lies in shortening surgery duration,reducing ultrasound power,and deseasing the loss of corneal endothelial cells (CECs).Objective This study was to compare the efficacy and safety of pre-chop technique using a reverse-chopper and phaco-and-chop phaco technique to super high myopia associated with hard nucleus cataract.Methods A prospective randomized-controlled-clinical interventional study was performed.Fourty eyes of 40 high myopia associated with cataract patients with Ⅲ-ⅣV degree of nucleus were enrolled in Beijing Tongren Hospital from March to September 2016.The patients were randomized into the pre-chop group and matched phaco-and-chop group according to random number table,and the self-made reverse chopper-assisted pre-chop phacoemulsification (phaco) surgery and phaco-and-chop phaco surgery were performed on the eyes of different groups,respectively.The phaco power,effective phaco duration and best corrected visual acuity (BCVA) were recorded and compared between the two groups to evaluate the efficacy,and the loss rate of corneal endothelial cells and eyes in different grades of cornea edema after operation were compared between the two groups to assess the safety of surgery procedure.Written informed consent from each patient was obtained prior to relevant examination and surgery.Results The surgery was finished smoothly in the eyes.The mean effective phaco duration was (47.30±11.29) seconds and (57.70± 14.51) seconds in the pre-chop group and phaco-andchop group,respectively,with a significant difference between them (t =-2.530,P =0.016).The BCVA was better at the seventh day after surgery in the pre-ehop group than that in the phaco-and-chop group (4.75t0.11 vs.4.67± 0.14),showing a significant difference between the two groups (t=2.147,P=0.038).In 1 month after surgery,the CECs loss rate was (10.82±3.77)％ in the pre-chop group,which was lower than (16.11±6.47)％ in the phacoand-chop group (t=-3.758,P=0.001).The number of the eyes with grade 2-3 of corneal edema in the pre-chop group was significantly decreased in comparison with the phaco-and-chop group 7 days after surgery (Z =11.822,P=0.008).Conclusions Compared with the conventional phaco-and-chop technique,reverse-chopper prechop technique appears to have a better efficacy and safety in phaco surgery for high-myopia associated with hard nuclear cataractous eyes.

Phacoemulsification in posterior polar cataract / Facoemulsificação na catarata polar posterior

ABSTRACT Purpose: To evaluate the results and complications of phacoemulsification surgery in eyes with posterior polar cataracts and compare the techniques of viscodissection and hydrodissection. Methods: The medical records of 29 consecutive patients (16 males, 13 females) with posterior polar cataracts (44 eyes) who had undergone cataract surgery were retrospectively reviewed. Patients were divided into two groups according to the technique used; viscodissection was applied to the experimental group (group 1) and hydrodissection to the control group (group 2). Results: The postoperative best corrected visual acuity (BCVA) was 0.19 ± 0.22 logMAR (mean ± standard deviation) (range 0.00-0.70) in group 1 and 0.25 ± 0.18 logMAR (range 0.00-0.70) in group 2. Although the mean postoperative BCVA in group 1 was greater than that in group 2, the difference was not statistically significant (p=0.165). The mean postoperative BCVA was significantly greater than the mean preoperative BCVA in both groups (p=0.00). Intraoperatively, posterior capsular rupture occurred during the removal of the cortex in three eyes (13%) of group 1 patients, with vitreous loss and anterior vitrectomy in one eye only. In group 2, six eyes (28.5%) presented posterior capsular rupture, and anterior vitrectomy was performed because of vitreous loss in three eyes. Although the percentage of posterior capsular rupture was greater in group 2, the difference was not statistically significant (p=0.207). Conclusions: Complications in posterior polar cataract surgeries can be overcome by being careful throughout the surgery and using proper techniques. Viscodissection may be better for avoiding posterior capsular rupture than hydrodissection.

RESUMO Objetivo: Avaliar os resultados e complicações da cirurgia de facoemulsificação em olhos com catarata polar posterior e comparar as técnicas de viscodissecção e hidrodissecção. Métodos: Os prontuários de 29 pacientes consecutivos (16 homens, 13 mulheres) com posterior cataratas polares (44 olhos), que haviam sido submetidos a cirurgia de catarata foram analisados retrospectivamente. Os pacientes foram divididos em dois grupos de acordo com a técnica utilizada; viscodissecção foi aplicada ao grupo experimental (grupo 1) e hidrodissecção para o grupo de controle (grupo 2). Resultados: No pós-operatório, a melhor acuidade visual corrigida (BCVA) foi 0,19 ± 0,22 logMAR (média ± desvio padrão) (variação 0,00-0,70) no grupo 1 e 0,25 ± 0,18 (0,00-0,70) logMAR no grupo 2. Embora a média da BCVA pós-operatória do grupo 1 tenha sido maior do que a do grupo 2, a diferença não foi estatisticamente significativa (p=0,165). A melhor acuidade visual corrigida pós-operatória foi significativamente melhor do que no pré-operatório, em ambos os grupos (p=0,00). No grupo 1, houve ruptura capsular posterior durante a remoção do córtex em três olhos (13%); houve perda vítrea e necessidade de vitrectomia anterior mas apenas em destes olhos. No grupo 2, a ruptura da cápsula posterior ocorreu em seis olhos (28,5%); vitrectomia anterior foi necessária após a perda vítrea em três destes olhos. Embora a porcentagem de ruptura da cápsula posterior tenha sido maior no grupo 2, a diferença não foi estatisticamente significativa (p=0,207). Conclusões: As complicações em cirurgias de catarata polar posterior podem ser superadas com cautela durante toda a cirurgia e usando técnicas adequadas. Viscodissecção é melhor para evitar a posterior ruptura capsular do que hidrodissecção.

A comparative study between reverse chopper-assisted prechop phacoemulsification and stop-and-chop phacoemulsification for cataract with Ⅳ degree hard nucleus / 中华实验眼科杂志

Background The pre-chop technique can decrease the use of ultrasound power,and thus reducing the loss of corneal endothelial cells (CECs) and injuries of other intraocular structures.Many currently developed manual pre-chop techniques restrict the wide application of the pre-chop technique because of their intrinsic disadvantages.The present study describes a manual pre-chop technique for pre-slicing the lens nucleus by using a novel reverse chopper,which has not been reported yet.Objective This study was to compare the efficacy and safety of pre-chop technique using a reverse chopper and stop-and-chop phacoemulsification technique on Ⅳ degree hard nucleus cataract.Methods A prospective clinical-controlled interventional study was performed.Thirty-two eyes of 32 cataract patients with Ⅳ degree of nucles were enrolled in People's Hospital of Hetian District from March 2015 to January 2016.The patients were randomized into the prechop group and matched stop-and-chop group according to random number table.The self-made reverse chopper-assisted pre-chop phacoemulsification surgery and stop-and-chop phaco surgery were performed on the eyes of corresponding groups,respectively.The ultrasound power,effective phaco duration,corneal endothelium loss rate,the eye number of different grade of cornea edema after operation and vision outcome were compared between the two groups.Written informed consent was obtained prior to relevant examination and surgery.Results The mean effective Phaco durations were 42.56 (39.31,45.81) seconds and 78.63 (73.85,83.40) seconds in the prechop group and stop-and-chop group,with a significant difference between them (Z =-4.937,P =0.000).The eye number with different degree of best corrected visual acuity (BCVA) was significantly different between the two groups,at postoperative day 1 and day 3 (P =0.013,0.033).The number of corneal endothelial cells (CECs) 1 month after surgery was (2 026.05 ± 154.03)/mm2 in the prechop group,and the number was (1 866.50-± 117.16)/mm2 in the stop-and-chop group,with a significant difference between them (t =3.298,P=0.003).The CECs loss rate was (13.36±2.85) ％ in the prechop group,which was lower than (25.77±3.81) ％ in the stop-and-chop group (t=-6.996,P=0.000).The eye number with different degree of corneal edema was significantly decreased in the prechop group compared with the stop-and-chop group at postoperative day 1 and day 3 (P =0.001,0.002).Conclusions Compared with the stop-and-chop phaco technique,a reverse chopper-assisted pre-chopping technique can decrease the intraoperative complication,lighten the postoperative damage of CECs and accelerate visual rehabilitation in hard nucleus cataract eyes.

A comparative study of cystotome-assisted prechop technique with stop-and-chop technique for pseudoexfoliation syndrome with cataract / 中华实验眼科杂志

Background Pseudoexfoliation syndrome (PEX) has a high incidence in Uygur population and usually leads to secondary glaucoma and complicated cataract.The abnormal change of lens tissue and degeneration of zonular fibers bring a lot of difficulties for phacoemulsification (phaco) with intraocular lens implantation,especially stop-and-chop phaco technique.Prechop technique is a new choping technology,but its application in PEX with cataract is less.Objective This study was to compare the efficacy and safety of pre chop phaco technique and stop-and-chop phaco technique for PEX combined cataract.Methods A randomized controlled Clinical trial was designed.Forty-one eyes of 41 patients with PEX combined cataract of Ⅲ degree of nucleus were enrolled in People's Hospital of Hetian District from March 2015 to January 2016.The patients were randomized into the prechop group and stop-and-chop group according to random nubmer table,and cystotome-assisted prechop phaco surgery and stop-and-chop phaco surgery were performed in different groups,respectively.The effective phaco duration,corneal endothelium loss rate,cornea edema eye number after operation,vision outcomes and complications were compared between the two groups.Results The mean effective phaco duration was 14.0 (13.0,16.5) minutes and 18.5 (16.5,24.0) minutes in the prechop group and stop-and-chop group,with a significant difference between them (Z =17.354,P ＜ 0.01).The corneal endothelial cells were (2 101.90 ± 209.08)/mm in the prechop group,and the number was similar to (2 002.30 ± 207.04)/mm of the stop-and-chop group (t =-1.530,P =0.134).Corneal endothelial cell lossing rate was (8.27±2.23)％ in the prechop group,which was lower than (13.09±4.26)％ in the stop-and-chop group (t =3.810,P =0.001).The BCVA was better in the prechop group than that in the stop-and-chop group in postoperative day 3 (P =0.044),and the corneal edema degree was not signigicantly different in postoperative day 1 and day 3 between the two groups (P=0.221,0.446).Intraoperative complication was rapture of zonule and occurred in 1 eye and 2 eyes in the prechop group and stop-and-chop group,respectively.Conclusions Compared with the stop-and-chop phaco technique,the prechop phaco tequnique can decrease intraoperative complication,lighten the postoperative damage of corneal endothelial cells and accelerate visual rehabilitation in PEX combined with cataract patients.

Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study / Faco torsional utilizando as ponteiras Kelman mini-flared, reversa e sidewinder: um estudo prospectivo comparativo randomizado

Purpose: To compare the efficiency of surgical procedures using three phaco tip designs in torsional phacoemulsification using the bevel-down technique. Methods: In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini-flared 30-degree Kelman tip, or Sidewinder 30-degree Kelman tip. Clinical measurements included preoperative and 3-month postoperative corrected distance visual acuity (CDVA), endothelial cell counts (ECC), and preoperative and 1-day postoperative central corneal thickness (CCT). Intraoperative measurements included phaco time, torsional time, aspiration time, case time, cumulative dissipated energy (CDE), and balanced salt solution volume (BSS). Results: The study evaluated 150 eyes of 150 patients. Intraoperatively, there was no statistically significant difference in cumulative dissipated energy, case time, torsional time, and aspiration time between the three tip configurations. However, less phaco time was used with the mini-flared 45-degree Kelman tip (p=0.02) than that with the Sidewinder 30-degree Kelman tip or reversed mini-flared 30-degree Kelman tip. The mini-flared 45-degree Kelman tip and the reversed mini-flared 30-degree Kelman tip required significantly less balanced salt solution volume than that required by the Sidewinder 30-degree Kelman tip (p=0.009). There was no statistically significant difference in corrected distance visual acuity and endothelial cell counts between tips 3 months postoperatively (p>0.05). Conclusion: All three tips were effective with no intraoperative complications. When using torsional phacoemulsification through microincisions and the prefracture technique with the bevel-down technique, the mini-flared 45-degree Kelman tip required a lower mean phaco time than the reversed mini-flared 30-degree Kelman tip and the Sidewinder 30-degree Kelman tip. .

Objetivo: Comparar a eficácia cirúrgica da facoemulsificação com tecnologia torcional utilizando 3 modelos diferentes de ponteiras. Métodos: Neste estudo prospectivo, randomizado, mascarado, os pacientes foram aleatoriamente distribuídos para serem submetidos a cirurgia de facoemulsificação coaxial torcional utilizando a ponteira Kelman mini-flared de 45 graus, ou Kelman reversed mini-flared de 30 graus ou Kelman Sidewinder de 30 graus. Os parâmetros avaliados incluíram: acuidade visual com correção (AVCC) para longe; contagem de células endoteliais (CCE) pré-operatória e pós-operatória, ao final de 3 meses; espessura corneana central (ECC) pré-operatória e no primeiro dia pós-operatório. Medidas intraoperatórias incluíram tempo de facoemulsificação, tempo de energia torcional, tempo da aspiração, tempo cirúrgico, energia dissipada acumulada (CDE) e volume de solução salina balanceada (BSS). Resultados: Este estudo avaliou 150 olhos de 150 pacientes. No intraoperatório, não foram observadas diferenças significativas na energia dissipada acumulada, tempo de facoemulsificação, tempo de energia torcional, e tempo de aspiração entre os 3 modelos de ponteira. No entanto, foi utilizando menos tempo de faco com a ponteira Kelman mini-flared de 45 graus (p=0,02) quando comparado às ponteiras Kelman Sidewinder de 30 graus e reversa mini-flared de 30 graus. A ponteira Kelman mini-flared de 45 graus e a reversa mini-flared de 30 graus utilizaram menos solução salina balanceada quando comparado à ponteira Sidewinder de 30 graus (p=0,009). Não foram observadas diferenças significativas na acuidade visual com correção, contagem de células endoteliais e espessura corneana central entre as diferentes ponteiras ao final do estudo (p=0,05). Conclusão: As 3 ponteiras foram eficazes e não apresentaram complicacões intraoperatórias. Quando foi utilizando o faco torcional através de microincisão com a técnica da pré-fratura, a ponteira Kelman mini-flared ...

Treatment of astigmatism during phacoemulsification / Tratamento do astigmatismo durante a facoemulsificação

Purpose: To compare the effectiveness of limbal relaxing incisions (LRI) with that of toric intraocular lens (IOL) implantation for the treatment of astigmatism during phacoemulsification using nonvectorial (predictability, safety, and efficacy) and vectorial analyses. Methods: This longitudinal observational case series assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism of 0.75-2.50 diopters (D) in both eyes. Patients were randomly assigned to 2 groups: a toric IOL group, which received toric IOLs in both eyes, and an LRI group, which received spherical IOLs associated with LRI placement in both eyes. All patients were evaluated at 1, 3, and 6 months after surgery, when refractive astigmatism analysis was performed using both nonvectorial and Alpins vectorial methods. Outcomes were assessed within each group and compared between groups. Results: The proportion of eyes within ±0.50 D of the intended correction at 3 and 6 months after surgery was 75% and 71.88%, respectively, in the LRI group and 40% and 66.67%, respectively, in the toric IOL group. In the remaining period, the proportion was greater in the toric IOL group. The safety index showed no difference at any time point. The efficacy index at 1 and 3 months after surgery was significantly higher in the toric IOL group (0.43 and 0.44, respectively) than in the LRI group (0.31 and 0.36, respectively). At 6 months after surgery, the status of eyes in the LRI group was as follows: 53.13% were undercorrected, 43.74% achieved the intended correction, and 3.13% were overcorrected. In the toric IOL group, 16.76% eyes were undercorrected, 76.67% achieved the intended correction, and 6.67% were overcorrected. The success rates for astigmatic surgery, astigmatism reduction at the intended axis, and astigmatism corrected were 43%, 62%, and 64%, respectively, in the LRI group and 57%, 81%, and 94%, respectively, in the toric IOL group. Conclusions: ...

Objetivo: Comparar incisões relaxantes limbares (IRL) e lentes intraoculares (LIO) tóricas tanto em termos não-vetoriais (efetividade, segurança e eficácia), quanto vetoriais no tratamento do astigmatismo por ocasião da facoemulsificação. Métodos: Estudo observacional longitudinal (série de casos) no qual foram avaliados 62 olhos de 31 pacientes consecutivos de catarata com astigmatismo corneano pré-operatório entre 0,75 e 2,50 dioptrias (D) para ambos os olhos. Os pacientes foram aleatoriamente distribuídos entre 2 grupos: "1" submetido a implante de lentes intraoculares AcrySof ToricTM em ambos os olhos e "2" com implante bilateral de lentes intraoculares tóricas AcrySof NaturalTM complementada por incisões relaxantes limbares. Todos os pacientes foram reavaliados com 1, 3 e 6 meses de pós-operatório, sendo feitas análises do astigmatismo refracional por métodos não-vetoriais, como pela análise vetorial de Alpins, interessando os resultados dentro de cada grupo e entre os grupos. Resultados: O porcentual de olhos entre ±0,50 D da correção pretendida no grupo incisões relaxantes limbares foi de 75 e 71,88%, respectivamente, em comparação aos 40 e 66,67% do grupo lentes intraoculares tóricas aos 3 e 6 meses de pós-operatório. Nos outros períodos avaliados, os porcentuais foram favoráveis ao grupo lentes intraoculares tóricas. O índice de segurança não demonstrou diferença em nenhum dos períodos. O índice de eficácia foi estatisticamente maior para o grupo lentes intraoculares tórica com 1 e 3 meses de pós-operatório (0,43 e 0,44), em comparação ao grupo incisões relaxantes limbares (0,31 e 0,36). Aos 6 meses, o porcentual de olhos, para o grupo incisões relaxantes limbares, foi: hipocorreção ...

The comparative study of IOL Master and A ultrasound combined with corneal topography measurement for IOL power / 中国医师杂志

Objective To investigate the difference of IOL Master and A-ultrasound combined with corneal topography meas-urement in intraocular lens ( IOL) power calculation .Methods A total of 84 eyes of 60 cataract patients received phacoemulsification and intraocular lens implantation surgery were selected in Xiangya Hospital from March 2010 to September 2011.There were 57 eyes of 42 age-related cataract patients and 27 eyes of 18 complicated cataract patients .The patients were divided into IOL Master group and A ultrasound combined with corneal topography measurement group .Before surgery , in IOL Master group , axial length ( AL) and corneal curvature were measured with IOL Master , IOL power was calculated according to the Haigis , SRK/T formula and so on.At the same time the axial length ( AL) and corneal curvature were measured with A ultrasound combined with corneal topography respectively and IOL power was calculated by SRK/Ⅱ formula.In A ultrasound combined with corneal topography measurement group , axial length ( AL) and corneal curvature were measured with A ultrasound combined with corneal topography respectively , IOL power was calculat-ed according to the SRK/Ⅱformula.3 months postoperatively , all the patients were conducted refractive outcome and calculating mean absolute refractive error(MAE).Finally the data were analysed.Results ⑴In IOL Master group, before operation there was no sig-nificant difference in mean axial length between IOL Master and A-ultrasound measurement ( P >0.05 ) , while in the patients with AL>26 mm the axial length was (28.53 ±0.57)mm and (29.42 ±0.64)mm using IOL Master and A-ultrasound measurement respec-tively ( P <0.05).The mean corneal curvature was (42.12 ±0.31)D and (43.09 ±0.27)D using IOL Master and corneal topogra-phy measurement respectively ( P <0.01).The mean IOL power were (17.06 ±0.48)D and (16.37 ±0.56)D in IOL Master group and A ultrasound combined with corneal topography measurement group respectively ( P <0.05 ) .⑵3 months postoperatively , the MAE was (0.07 ±1.05)D and (0.16 ±0.81)D in IOL Master group and A-ultrasound combined with corneal topography measure-ment group( P <0.05) respectively.Conclusions In cataract patients with normal axial length , IOL Master and A-ultrasound com-bined with corneal topography have high consistency for axial length measurement and IOL power calculation .But in cataract patients with high myopia , IOL Master is more accurate for axial length measurement and IOL power calculation compared to A -ultrasound com-bined with corneal topography .