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@#AIM: To compare the consistency of IOL Master 700 with IOL Master 500 and A-mode ultrasound for biological measurements, and evaluate the measurements of IOL Master 700 in preoperative examinations of cataract patients. <p>METHODS:In this prospective study, a total of 52 patients(100 eyes)diagnosed as age-related cataract were selected at the Nanjing Medical University Eye Hospital. All the patients were examined in turn by IOL Master 700, IOL Master 500 and A-mode ultrasound. Measurements by these three instruments were compared for axial length(AL), corneal curvature(Km), central anterior chamber depth(ACD), white-to-white(W-W)and pupil diameter(P). The results were analyzed by one-way ANOVA, Pearson correlation and Bland-Altman. <p>RESULTS: The detection rates of AL and ACD with IOL Master 700, IOL Master 500 and A-mode ultrasound were 98%, 87%, 99% and 100%, 99%, 99%; respectively. The detection of Km with IOL Master 700 and IOL Master 500 were 100%, 99%. The detection of W-W and P were both 99%. Among them, 24 eyes had high myopia, posterior scleral grape swelling and axial length ≥26mm. The detection of AL with IOL Master 700, IOL Master 500 and A-mode ultrasound were 96%, 79%, 96%. There was a significant difference in AL and ACD between three instruments(<i>F</i>=11.58, <i>P</i>=0.03; <i>F</i>=12.46, <i>P</i>=0.02). There were no significant differences in Km, W-W and P parameters among three instruments(all <i>P</i>>0.05). The average difference between three instruments for AL measurement: IOL Master 700 and IOL Master 500 was 0.05±0.12mm, IOL Master 700 and A-mode ultrasound was 0.16±0.14mm; The average difference between three instruments for AL measurement in axial length≥26mm: IOL Master 700 and IOL Master 500 was 0.17±0.16mm, IOL Master 700 and A-mode ultrasound was 0.55±0.22mm. The Pearson's correlation analysis showed that there was a high correlation between the measured results of each equipment. The consistency of AL results using Bland-Altman analysis showed there was good consistency in the range of 95% consistency.<p>CONCLUSION: There was high consistency in ocular biological measurements between three instruments in cataract eyes. However, the detection rate of IOL Master 700 in AL was higher than that of IOL Master 500, and the accuracy of the IOL Master 700 measurement was higher in the AL measurement in high myopia with posterior staphyloma. Compared with traditional examination equipment, IOL Master 700 has better penetration and accuracy to provide more accurate measurement parameters.
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@#AIM: To study the effects of phacoemulsification(Phaco)combined with different types of intraocular lens implantation(IOL)on age-related cataract. <p>METHODS: A retrospective study was performed on 105 elderly patients with age-related cataract who were treated with surgery in our hospital, and they were divided into group A(35 cases, 51 affected eyes), group B(35 cases, 49 affected eyes)and group C(35 cases, 52 affected eyes). All subjects were treated by IOL+Phaco, and types of IOL in the three groups were three-piece and single-piece Natural and Rayner. The preoperative and postoperative biological measurement indexes and postoperative complications were compared among the three groups. <p>RESULTS: At 3mo after surgery, the intraocular pressure(IOP)in three groups was significantly decreased(<i>P</i><0.05)while the angle opening distance(AOD500), trabecular iris angle(TIA500), central anterior chamber depth(ACD), trabecular-ciliary processes distance(TCPD), each quadrant angle, uncorrected visual acuity and best corrected visual acuity(BCVA)were significantly increased(<i>P</i><0.05). The ACD and TIA500 in group A were significantly higher than those in groups B and C(<i>P</i><0.05),and there were no significant differences in the uncorrected visual acuity, BCVA and other biological measurement indexes among the three groups(<i>P</i>>0.05). There were significant differences in vertical shift and horizontal shift of intraocular lens among the three groups at 1mo and 3mo after surgery(<i>P</i><0.05), and the vertical shift and horizontal shift of intraocular lens at 1mo and 3mo after surgery in group A were lower than those in groups B and C(<i>P</i><0.05), and there were no significant differences in vertical shift and horizontal shift between group B and group C(<i>P</i>>0.05).The incidence rate of posterior capsule wrinkle in group A after surgery was obviously higher than that in group B and group C(<i>P</i><0.05). <p>CONCLUSION: The intraocular stability and safety of Phaco+single-piece IOL are better than those of Phaco+ three-piece IOL, but Phaco+ three-piece IOL has deeper ACD after surgery and can prevent the forward shift of IOL, and they have their own advantages and disadvantages.
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@#Risk factors including short axial length, shallow anterior chamber, narrow angles, spherical lens and other characters such as gender, age and family history are well known to be related to the attack of primary angle-closure glaucoma(PACG). In recent years, with the development of advanced techniques such as the anterior segment optical coherence tomography(AS-OCT)and ultrasound biomicroscope(UBM), the technical supports for the measurement of anterior segment parameters were largely provided, which made it possible to quantify risk factors of PACG precisely. In this paper, the relevant research progresses of commonly used anatomic parameters and their significances in pathogenesis of PACG were reviewed.
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AIM: To compare the accuracy of intraocular lens(IOL)power calculations by using five formulas(Haigis, SRK-T, Hoffer Q, Holladay-1, SRK-Ⅱ)in eyes with long axial lengths in order to improve the accuracy of predicating IOL powers.METHODS: Fifty-one eyes of 51 cases of age-related cataract and with mild long axial(24.5mm27mm) were collected who`s optical biometry were performed by the Zeiss IOL Master500 before operation.They underwent regular phacoemulsification and posterior chamber IOL implantation.The actual postoperative refraction was measured with the methods of phoropter and subjective optometry 3mo after surgery.Then we compared the differences of the predicted and actual postoperative refraction of the five formulas in each group.RESULTS: In the mild axial lengths cases, the differences between SRK Ⅱ formula and the other four formulas were statistically significant (P0.05).In the moderate and severe long axial lengths cases, the differences between SRK Ⅱ formula and the other four formulas were statistically significant (P0.05).The differences of all the five formulas between the two groups were statistically significant (P<0.05).CONCLUSION: In the mild axial lengths cases, Haigis, SRK-T, Hoffer Q, Holladay-1 performed well.In the moderate and severe long axial lengths cases, Haigis, SRK-T and Holladay-1 performed better than other formulas.The accuracy of all the five formulas decreases as the axial length getting longer.
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AlM:To investigate biological measurement parameters of anterior segment in acute angle- closure glaucoma ( AACG) .METHODS:Forty-six eyes of 46 patients with AACG and 52 eyes of 52 patients with shallow anterior chamber and 50 eyes of 50 normal individuals were examined. The parameters of anterior segment including chamber crowd rate (CCR), lens thickness (LT), lens position (LP) and anterior chamber depth ( ACD ) were measured by A-ultrasound according to different ages in each group. The data were performed statistical analysis in three groups.RESULTS: ln each age range group (≥50 ~ 59 years old, ≥60 ~ 69 years old, ≥70 years old ) , statistically significant differences in three groups ( AACG, shallow anterior chamber group and the controls ) were found in CCR, LT, LP, ACD (P 0. 05 ) between AACG and shallow anterior chamber group in each age range group.CONCLUSlON: CCR can be used as the index of evaluating crowding state of anterior segment in AACG patients and the sensitivity is better than LT and LP.
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Background Central corneal thickness (CCT)is an important parameter to evaluate corneal healthy status and is crucial for surgical planning.However,clinical study found that the center of cornea does not correspond to the thinnest point of cornea.Thus,it is essential to characterize the minimum corneal thickness(MCT) and its location.Objective Present study was to determine the thickness and location of MCT and its relationship to the fellow eye using Pentacam High Resolution technique.Methods The 564 eyes from 282 Chinese myopic patients were reviewed in this study.The CCT,MCT,pupillary central corneal thickness(PCT) and x-y coordinate of thinnest point were bilaterally measured.Written informed consent was obtained prior to the ocular biomedical measurement.Results CCT was (540.07±31.78) μm in the right eyes and (539.24±31.06) μm in the lefi eyes; PCT was (540.25±30.75)μm in the right eyes and (539.48±31.00)μm in the left eyes.MCT was (537.87± 31.91)μm in the right eyes and (536.35±31.24)μm in the left eyes,showing significant differences in all the parameters between the right eyes and left eyes expect for PCT(CCT:P=0.046;PCT:P=0.065 ;MCT:P=0.000).The C CT,PCT and M CT were significantly correlated between the right eyes and left eyes (r =0.97,0.97,0.98,P＜ 0.01).Bland-Altman plot showed a good consistence between the both eyes.The mean distance from the center was (0.50±0.21) mm in the right eyes and (0.56±0.22)mm in the left eyes,showing a significant difference (P =0.000).The difference between CCT and MCT was approximately (2.20±1.74)μm in the right eyes and (2.88±1.75) μm in the left eyes.The location of MCT in both the right eyes and left eyes tended to symmetry along the vertical midline.The distance between the R (x,y) to transformed L (x,y) was (0.29 ± 0.17)mm and the angular distance was (28.28±28.21)degree.Conclusions This study offers a range of MCT and its location in Chinese myopic patients.The difference exists between the CCT and MCT in bilateral eyes.The location of the thinnest point tends to be symmetrical along the vertical midline between the both eyes.The changes of these parameters may be helpful for the diagnosis of some corneal diseases.
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Background The neovascular form of the disease usually causes severe vision loss in a number of eye diseases.Special-domain optical coherence tomography (SD-OCT) provides high-quality in retinal imaging and the possibility of the measurement in vivo.Objective This study aimed to investigate the feasibility of SD-OCT dynamically measuring choroidal neovascularization (CNV).Methods CNV was induced in 30 left eyes of 30 clean Brown Norway(BN)rats by retinal photocoagulation with the laser parameter as follows: wavelength 532 nm,exciting power 200 mW,spot diameter 100 μm and irradiating time 50 ms.Bubble or less retinal bleeding was thought as Brunch membrane breakage and CNV model establishment.Fundus fluorescein angiography(FFA) was performed to determine the establishment of CNV model and scored based on the fluorescein leakage on 3,7,14,21 days after photocoagulation.Meanwhile,CNV memberane thickness (CMT) was dynamically measured in vivo as the maxiume value from retinal inner limiting membrane through choroidal vessel layer in various time points.Histopathologic examination was used in the 14th day to evaluate and verify the result of SD-OCT.The right eyes were as controls.Results FFA examination showed that disc-like leakage of fluorescein appeared in 7 days and extended in 14 days after photocoagulation with the scores of 1.6±0.4,2.5±0.6 and 2.4±0.5 in 7,14 and 21 days,showing a significant difference among them(F=13.11,P＜0.01).The fluorescein leakage score was significantly higher in 14 and 21 days than that of 7 days(both P＜0.05).CMT measured by SD-OCT was(76.33±10.09),(102.03±14.21)and(98.03±13.76) μm in 7,14 and 21 days after photocoagulation respectively,with a significant difference among 3 time points (F=23.25,P＜0.01),and that in 14 and 21 days was significantly declined in comparison with 7 days(both P＜0.05).The results of SD-OCT showed a consistent tendency with that of FFA.Histopathological examination showed CNV formation in 14 days after photocoagulation.Conclusions Experimental CNV model was successfully induced by laser photography.SD-OCT technology allows excellent visualization of CNV in vivo.
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Cataract surgery is now often referred to as refractive surgery.It has come into the focus in recent years to choose the intraocular lens of appropriate power so as to achieve the expected postoperative refraction.Two main factors influence the measurement of intraocular lens power(IOL),the IOL power calculation formula and biological measurement of the ocular.The achievement of expected surgical outcome depends on the selection of the IOL power calculation formula and biological measurement instrument that suit the intraocular lens the specific patient.The article presents an overview of IOL power calculation with a focus on the above two aspects.