• Users Online: 260
  • Home
  • Print this page
  • Email this page
Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 


 
   Table of Contents      
ORIGINAL ARTICLE
Year : 2018  |  Volume : 5  |  Issue : 1  |  Page : 6-11

The central corneal thickness and anterior chamber depth of adults in a Nigerian population


Department of Optometry, Faculty of Life Sciences, University of Benin, Benin City, Edo State, Nigeria

Date of Submission11-Apr-2018
Date of Acceptance09-Apr-2020
Date of Web Publication11-Jul-2020

Correspondence Address:
Dr. Juno Ohiremere Okukpon
Department of Optometry, Faculty of Life Sciences, University of Benin, Benin City, Edo State
Nigeria
Login to access the Email id


DOI: 10.4103/bijo.bijo_3_18

Rights and Permissions
  Abstract 


Introduction: The central corneal thickness (CCT) and anterior chamber depth (ACD) are important ocular parameters used in the assessment of risk factors relating to ocular morbidities. Determining the relationship between these parameters is fundamental to understanding and developing strategies to help the early diagnoses and management of some ocular conditions. The aim of this study was to determine the CCT and ACD of adults in a Nigerian population and also investigate the correlations between them in the study population.
Materials and Methods: Sixty-six individuals consisting of 31 males and 35 females between 18 and 68 years participated in this study. The CCT and ACD were measured with ultrasound pachymetry and ultrasonography (PacScan 300, Sonomed International Corp., USA). Data were analyzed with Statgraphics Plus (Statistical Graphics Corp., USA) and SPSS version 22.0 (SPSS Inc., Chicago, IL, USA) software.
Results: The mean age, CCT, and ACD were 37.2 ± 11.6 years, 536.71 ± 23.89 μm, and 3.30 ± 0.32 mm, respectively. The CCT and age showed a negative trend, not statistically significant (P = 0.12). Regression analysis performed on ACD and age showed an inverse correlation (P < 0.0001). There was no difference (P > 0.05) in mean CCT between males (536.7 ± 28.38 μm) and females (536.71 ± 19.50 μm). Similarly, there was no difference in mean ACD between males (3.36 ± 0.34 mm) and females (3.24 ± 0.3 mm) although not statistically significant (P = 1.48).
Conclusion: There was no statistically significant correlation between CCT and ACD, and a prediction of approximately 0.10-mm decrease in ACD and approximately 4.0-μm decrease in CCT per decade was made.

Keywords: Anterior chamber depth, central corneal thickness, pachymetry, ultrasonography


How to cite this article:
Iyamu E, Okukpon JO, Uduoise I. The central corneal thickness and anterior chamber depth of adults in a Nigerian population. Albasar Int J Ophthalmol 2018;5:6-11

How to cite this URL:
Iyamu E, Okukpon JO, Uduoise I. The central corneal thickness and anterior chamber depth of adults in a Nigerian population. Albasar Int J Ophthalmol [serial online] 2018 [cited 2021 Jul 29];5:6-11. Available from: https://www.bijojournal.org/text.asp?2018/5/1/6/289594




  Introduction Top


The cornea is the most anterior refractive surface of the optical system of the eye,[1] and together with the anterior chamber and the lens, it refracts light, accounting for approximately two-thirds of the eye's total optical power.[2] The cornea is also the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The measurement of the central part of the cornea is an important indicator of cornea health,[3] known as central corneal thickness (CCT), and it is a highly heritable trait proposed to influence disorders of the anterior segment of the eye.[4] CCT plays an important role in both the diagnostic/therapeutic assessment of glaucoma and corneal diseases, contact lens use, and in refractive surgery.[5],[6]

The anterior chamber depth (ACD) lies between the posterior surface of the cornea that is the corneal endothelium and the iris.[7] The average of the ACD gives information on the anterior/equatorial growth of the eye. The ACD measurement is useful in ophthalmic practice, for instance, in cataract and refractive surgery, intraocular lens power and diameter, and screening for glaucoma risk factors.[8]

For several years, ultrasound pachymeters and ultrasound biometers have been used to study CCT and ocular ACD, which were used in this study to assess the CCT and ACD.[9],[10],[11],[12] The measurement and fundamental understanding of CCT and ACD is important because these parameters play an important role in the early diagnosis of glaucoma by ensuring proper intraocular pressure (IOP) correction. The aim of this study was to determine the CCT and ACD of adults in a Nigerian population and also investigate the correlations between the two parameters. The result of this study will further aid research in early diagnoses of some ocular morbidity by identifying risk factors associated with these parameters in this population.


  Materials and Methods Top


This was an observational, prospective, cross-sectional study to determine the relationship between CCT, axial length, and vitreous chamber depth. The participants were recruited after detailed optometric examination that included best-corrected visual acuity, refraction, slit-lamp examination, applanation tonometry, and fundus examination. Only Nigerians who had no ocular disease, no previous ocular surgery, normal IOP, normal blood pressure, and refractive error ≤±0.50 D and participants without comorbidities affecting CCT such as diabetes mellitus were included in the study. Exclusion criteria included previous ocular surgery (any type of eye surgery), glaucoma, trauma history, external eye disease, extensive pterygium, corneal edema or dystrophy, aphakia, amblyopia, and lack of cooperation.

The study was approved by the ethics and research committee in accordance with the tenets of the Helsinki Declaration involving human participants, and informed consent was obtained from all patients.

Procedure

Measurements were taken on the right and left eye of each participant throughout this research after sterilization of the probe. The participant was comfortably seated with the head upright and ayes in the primary position of gaze. The probe was sterilized with 70% alcohol and allowed to air-dry before each use and between measurements. A drop of topical anesthetic (Tetracaine HCl 0.1%) was instilled in the participant's eye. The probe was carefully aligned perpendicularly to and lightly applanating the cornea.

Central corneal thickness

Sterilized ultrasound pachymeter probe (speed: 1640 m/s and frequency: 20 MHz) was used to determine the CCT. The probe will be carefully aligned perpendicularly to and lightly applanating the anesthetized cornea.[12] Five readings were continually taken, and the average was calculated by the instrument as measured CCT.

Anterior chamber depth

Sterilized A-scan ultrasound biometer probe (speed: 1548/ms and frequency: 10 MHz) was used to determine the ACD. The probe will be carefully aligned perpendicularly to and lightly applanating the anesthetized cornea.[11] Five readings were continually taken, and the average was calculated by the instrument as measured ACD.

Statistical package

All data obtained were analyzed with Statgraphics Plus (Statistical Graphics Corp., USA) and SPSS version 22.0 (SPSS Inc., Chicago, IL, USA). Measures of spread including standardized kurtosis and standardized skewness were derived. The measured variables (CCT, spherical equivalent refractive error, and ACD) were tested for normality with the Kolmogorov–Smirnov Z-test (normal distribution when the lower P > 0.05). Analysis of variance was used to compare the variables across the age groups and post hoc test for pair-wise comparison within the groups. Gender-related differences in measured variables were tested with Student's t-test (unpaired). The correlation or association between variables was tested using regression analysis. P < 0.05 was considered statistically significant.


  Results Top


A total of 66 (n = 66) participants (132 eyes) aged between 18 and 68 years with a mean age of 37.2 ± 11.6 years, consisting of 31 males and 35 females, had participated in this study [Table 1].
Table 1: Descriptive statistics of the measured variable

Click here to view


Mean anterior chamber depth, central corneal thickness, and the effect of age

Regression analysis performed on ACD and age showed a statistically significant inverse correlation (r = −0.45, r2 = 19.9%, P < 0.0001). The linear regression model is represented by: ACD = 3.761–0.013 age. The model as fitted explains 19.9% of the variability in ACD. From the regression model, a prediction of approximately 0.10-mm decrease in ACD can be made. [Figure 1] shows the correlation of ACD on age and the linear regression line. The linear regression model is represented by: CCT = 551.7–0.404 age [Figure 2]. The model as fitted explains 3.8% of the variability in CCT. From the regression model, a prediction of approximately 4.0-μm decreases in CCT per decade can be made.
Figure 1: Correlation of anterior chamber depth and age with the linear regression line with 95% confidence interval of the regression line

Click here to view
Figure 2: Correlation of central corneal thickness and age with the linear regression line with 95% confidence interval of the regression line

Click here to view


Association between mean central corneal thickness and anterior chamber depth

Regression analysis performed on CCT and ACD showed no statistically significant correlation (P = 0.47). The linear regression model was represented by: CCT = 558.92 − 6.738ACD [Table 2].
Table 2: Pearson's correlation coefficient between measured variables

Click here to view


Effect of gender on central corneal thickness and anterior chamber depth

The difference in the mean age between males and females was not statistically significant (unpaired t-test: t = 1.09, Degree of freedom = 64, P = 0.28). There was no difference in the mean CCT between males and females (P > 0.05). Similarly, there was also no difference in the mean ACD between males and females (P = 1.48) [Table 3].
Table 3: Descriptive statistics of measured variables by gender

Click here to view



  Discussion Top


CCT and ACD have become a very important parameter of study due to their importance in the diagnosis of a number of ocular diseases and as an indicator in glaucoma risk factor.[3] CCT measurement is important for ensuring proper IOP correction in individuals with increased glaucoma risk, whereas ACD measurement is important for its correlation with axial length and its association with increased risk for angle closure if the anterior angle is shallow.[4] In this present study, CCT and ACD were measured to establish their distribution and their correlations in the Nigerian population.

The mean CCT from our study represented in [Table 1] was higher than the mean CCT reported by some other researchers,[5],[13],[14],[15],[16],[17],[18] but was closely in line with that of Osuobeni et al.,[7] Doughty and Zaman,[19] Mercieca et al.,[20] and Iyamu and Okukpon.[21] They reported a mean CCT of 535 ± 35.1, 536.0 ± 31, 535.0 ± 38, and 536.71 ± 23.89, respectively. These results also showed a lower CCT in some studies [Table 4].[9],[22],[23],[24],[25]
Table 4: Comparing findings with other studies

Click here to view


The correlation between CCT and age showed a negative trend, though not statistically significant was also comparable with the findings of Iyamu et al.[26] and Wong et al.[27] They also observed a negative but significant correlation between CCT and age (r = −0.25, P = 0.021; r = −0.237, P < 0.05, respectively); similar findings were recorded in other researchers work,[5],[15],[17],[21] who reported that there was no significant association between CCT and age in healthy participants.

The mean ACD [Table 4] in this study was higher than the mean ACD reported by some other studies,[22],[28],[29] but lower than that of the results of some researchers[24],[30] of ACD, although similar to reports of some studies.[5],[7],[10],[21],[31] Regression analysis performed on ACD and age showed a statistically significant inverse correlation (r = −0.45, P < 0.0001). An increase in age correlated with a mean 0.011 mm/year decrease in ACD was found in this study, ACD also decreased by 0.013 mm/year according to Hashemi et al.[29] Atchison et al.[32] also found that ACD decreased significantly with age at a rate of 0.011 mm/year, similar to the study of Dubbelman et al.,[33] with a rate of −0.010 mm/year and Koretz et al.[34] at −0.011 mm/year. The result in this study on ACD correlation with age was similar to that of Hosny et al. (−0.391, −0.623, P < 0.01),[11] Mashige and Oduntan (r = −0. 72, P < 0. 001),[5] Mohamed et al. (r = −0.391),[17] Fahmy (r = −0.307, P < 0.001),[25] Hashemi et al. (r = −0.014, P < 0.001),[29] and Eysteinsson et al. (r = −0.013, P < 0.001).[35] All these authors have concluded that ACD correlated inversely with patient's age.

Regression analysis performed on CCT and ACD showed that CCT did not correlate with ACD. This was in line with a number of studies.[5],[17],[23] They concluded that CCT was an independent factor unrelated to other ocular parameters. Yebra-Pimentel et al.[36] did not agree with this result, and they reported that ACD showed a significant statistical correlation with CCT.

There was no difference in mean CCT between males and females (P > 0.05) in this study. There was no statistical proof of influences on the CCT values on gender and age in this study. This is similar to the reports of numerous studies,[5],[15],[16],[17],[18],[19],[21],[23],[26],[34],[37],[38] and they found no significant difference in CCT between men and women. The finding of this study was not in agreement with some other studies,[9],[23],[39],[40],[41] and they suggested a gender difference in ocular biometrics with women having a significantly thinner cornea and in some other studies,[25],[31] males having thicker corneas than females, but differences were not statistically significant. The gender-related differences in ACD were statistically significant after adjusting for height (P < 0.0001). A number of studies[5],[12],[23],[29],[34],[38],[42],[43],[44],[45] have found significantly deeper ACD for males of up to 0.18 mm similar to the results in this study. On the other hand, Sanhermelando et al.,[9] Chen et al.,[23] and Atchison et al.[32] did not find a significant effect of gender on ACD. Previous researchers[5],[29],[38] have suggested that the gender differences in these parameters could be due to the fact that men are generally taller than women.


  Conclusion Top


The measurement of CCT and ACD has been shown to be a critical procedure in many clinical situations. This study showed that there was no statistically significant correlation between CCT and ACD. From the regression model, a prediction of approximately 0.10-mm decrease in ACD and a prediction of approximately 4.0-μm decrease in CCT per decade can be made. ACD measurement should be encouraged routinely, especially in older patients, as regression analysis performed on ACD and age showed a statistically significant inverse correlation. The measurement of CCT which cannot be overemphasized should be inculcated into routine examination, especially on a regular basis, as this is an important determinant in many ocular disorders such as glaucoma. The findings of this study can be used as a reference for diagnostic and clinical purposes.

Acknowledgment

The authors wish to thank Rachel Eye Centre, Area 11, Garki, Abuja, for granting the permission to use their facility for this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Saw SM, Chua WH, Hong CY, Wu HM, Chia KS, Stone RA, et al. Height and its relationship to refraction and biometry parameters in Singapore Chinese children. Invest Ophthalmol Vis Sci 2002;43:1408-13.  Back to cited text no. 1
    
2.
Goldstein BE. Sensation and Perception. 8th ed. Wadsworth: Cengage Learning; 2010.  Back to cited text no. 2
    
3.
Li A, Chen M. Central corneal thickness and its association with ocular parameters. MRA 2017;5:1-3.  Back to cited text no. 3
    
4.
Kanellopoulos AJ, Asimellis G. Correlation between central corneal thickness, anterior chamber depth, and corneal keratometry as measured by oculyzer II and wave light OB820 in preoperative cataract surgery patients. J Refract Surg 2012;28:895-900.  Back to cited text no. 4
    
5.
Mashige KP, Oduntan OA. Corneal parameters and their correlations with refractive error, axial length, anterior chamber depth and lens thickness in black South Africans. Guoji Yanke Zazhi (Int Eye Sci) 2017;17:597-603.  Back to cited text no. 5
    
6.
Ventura AC, Wälti R, Böhnke M. Corneal thickness and endothelial density before and after cataract surgery. Br J Ophthalmol 2001;85:18-20.  Back to cited text no. 6
    
7.
Osuobeni EP, Hegarty C, Gunvant P. The effect of central corneal thickness on estimates of the anterior chamber depth. Clin Exp Optom 2003;86:371-5.  Back to cited text no. 7
    
8.
Domínguez-Vicent A, Monsálvez-Romín D, Sanchis V, García-Lázaro S, Montés-Micó R. Comparison of anterior chamber depth measurement devices. J Emmetropia 2012;3:215-20.  Back to cited text no. 8
    
9.
Sanhermelando MV, Lleó A, Alonso L, Rahhal MS, de Tejada TH, Soriano FM, et al. Repeatability of central corneal thickness and ocular anterior chamber depth measurements with the orbscan topography system. Euro J Anat 2002;6:59-64.  Back to cited text no. 9
    
10.
Sanchis-Gimeno JA, Casanova J, Alonso L, Lleó-Pérez A, Ruiz-Torner A, Martínez-Soriano F. Morphometric study of the hyperopic central cornea. Eur J Anat 2001;5:77-81.  Back to cited text no. 10
    
11.
Hosny M, Alio JL, Claramonte P, Attia WH, Perez-Santonja JJ. Relationship between anterior chamber depth, refractive state, corneal diameter, and axial length. J Refract Surg 2000;16:336-40.  Back to cited text no. 11
    
12.
Wong TY, Foster PJ, Johnson GJ, Klein BE, Seah SK. The relationship between ocular dimensions and refraction with adult stature: The Tanjong paper survey. Invest Ophthalmol Vis Sci 2001;42:1237-42.  Back to cited text no. 12
    
13.
Eballe AO, Koki G, Ellong A, Owono D, Epée E, Bella LA, et al. Central corneal thickness and intraocular pressure in the Cameroonian nonglaucomatous population. Clin Ophthalmol 2010;4:717-24.  Back to cited text no. 13
    
14.
Gelaw Y, Kollmann M, Irungu NM, Ilako DR. The influence of central corneal thickness on intraocular pressure measured by goldmann applanation tonometry among selected Ethiopian communities. J Glaucoma 2010;19:514-8.  Back to cited text no. 14
    
15.
Iyamu E, Ituah I. The relationship between central corneal thickness and intraocular pressure: A comparative study of normals and glaucoma subjects. Afr J Med Med Sci 2008;37:345-53.  Back to cited text no. 15
    
16.
Lekskul M, Aimpun P, Nawanopparatskul B, Bumrungsawat S, Trakulmungkijkarn T, Charoenvanichvisit J, et al. The correlations between central corneal thickness and age, gender, intraocular pressure and refractive error of aged 12-60 years old in rural Thai community. J Med Assoc Thai 2005;88 Suppl 3:S175-9.  Back to cited text no. 16
    
17.
Mohamed H, Jorge LA, Pascual C, Walid HA, Juan JP. Relationship between anterior chamber depth, refractive state, corneal diameter, and axial length. J Ref Surg 2009;16:336-40.  Back to cited text no. 17
    
18.
Ntim-Amponsah CT, Seidu AY, Essuman VA, Forjour G, Tagoe NN, Coker A, et al. A study of central corneal thickness in glaucoma and nonglaucoma patients in a West African population. Cornea. 2012; 31:1093-1096.  Back to cited text no. 18
    
19.
Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: A review and meta-analysis approach. Surv Ophthalmol 2000;44:367-408.  Back to cited text no. 19
    
20.
Mercieca K, Odogu V, Fiebai B, Arowolo O, Chukwuka F. Comparing central corneal thickness in a sub-Saharan cohort to African Americans and Afro-Caribbeans. Cornea 2007;26:557-60.  Back to cited text no. 20
    
21.
Iyamu E, Okukpon JO. Relationship between central corneal thickness, vitreous chamber depth and axial length. JNOA2018;20:77-85.  Back to cited text no. 21
    
22.
Ahmad MI, Qureshi MA, Aldebasi YH. To study the effects of central corneal thickness, axial length, and anterior chamber depth on intraocular pressure. Sudanese J Ophthalmol 2017;9:10-5.  Back to cited text no. 22
  [Full text]  
23.
Chen MJ, Liu YT, Tsai CC, Chen YC, Chou CK, Lee SM. Relationship between central corneal thickness, refractive error, corneal curvature, anterior chamber depth and axial length. J Chin Med Assoc 2009;72:133-7.  Back to cited text no. 23
    
24.
Sanchis-Gimeno JA, Herrera M, Alonso L, Rahhal MS, Soriano FM. Morphometric differences between normal and dry eyes. Euro J Anat 2005;9:143-8.  Back to cited text no. 24
    
25.
Fahmy RM. Correlation between anthropomorphic measurements and ocular parameters among adult Saudi females. Austin J Clin Ophthalmol 2016;3:1070.  Back to cited text no. 25
    
26.
Iyamu E, Kio F, Idu FK, Osedeme B. The relationship between central corneal thickness and intraocular pressure in adult Nigerians without glaucoma. Sierra Leone. J Biomed Res 2010;2:95-102.  Back to cited text no. 26
    
27.
Wong AC, Wong CC, Yuen NS, Hui SP. Correlational study of central corneal thickness measurements on Hong Kong Chinese using optical coherence tomography, Orbscan and ultrasound pachymetry. Eye (Lond) 2002;16:715-21.  Back to cited text no. 27
    
28.
Ali NH, Abdelkhalek MO, Elghoneimy H. The comparison of anterior chamber parameters between normal and keratoconus eyes using scheimpflug photography. Int J Keratoconus Ectatic Corneal Dis 2016;5:105-8.  Back to cited text no. 28
    
29.
Hashemi H, Khabazkhoob M, Miraftab M, Emamian MH, Shariati M, Abdolahinia T, et al. The distribution of axial length, anterior chamber depth, lens thickness, and vitreous chamber depth in an adult population of Shahroud, Iran. BMC Ophthalmol 2012;12:50.  Back to cited text no. 29
    
30.
Doors M, Cruysberg LP, Berendschot TT, de Brabander J, Verbakel F, Webers CA, et al. Comparison of central corneal thickness and anterior chamber depth measurements using three imaging technologies in normal eyes and after phakic intraocular lens implantation. Graefes Arch Clin Exp Ophthalmol 2009;247:1139-46.  Back to cited text no. 30
    
31.
Jorge J, Rosado JL, Díaz-Rey JA, González-Méijome JM. Measuring CCT and ACD by Sirius and ultrasound. Clin Ophthalmol 2013;7:417-22.  Back to cited text no. 31
    
32.
Atchison DA, Jones CE, Schmid KL, Pritchard N, Pope JM, Strugnell WE, et al. Eye shape in emmetropia and myopia. Invest Ophthalmol Vis Sci 2004;45:3380-6.  Back to cited text no. 32
    
33.
Dubbelman M, van der Heijde GL, Weeber HA. The thickness of the aging human lens obtained from corrected Scheimpflug images. Optom Vis Sci 2001;78:411-6.  Back to cited text no. 33
    
34.
Koretz JF, Kaufman PL, Neider MW, Goeckner PA. Accommodation and presbyopia in the human eye – Aging of the anterior segment. Vision Res 1989;29:1685-92.  Back to cited text no. 34
    
35.
Eysteinsson T, Jonasson F, Sasaki H, Arnarsson A, Sverrisson T, Sasaki K, et al. Central corneal thickness, radius of the corneal curvature and intraocular pressure in normal subjects using non-contact techniques: Reykjavik eye study. Acta Ophthalmol Scand 2002;80:11-5.  Back to cited text no. 35
    
36.
Yebra-Pimentel E, González-Méijome JM, García-Resúa C, Giráldez-Fernández MJ. The relationships between ocular optical components and implications in the process of emmetropization. Arch Soc Esp Oftalmol 2008;83:307-16.  Back to cited text no. 36
    
37.
Hawker MJ, Naoakira N, Fujiko A, Hiroshi S, Yozo M. Relationship between age and central corneal thickness in a Japanese population. Japan J Clin Ophthalmol 2009;55:300-2.  Back to cited text no. 37
    
38.
Cosar CB, Sener AB. Orbscan corneal topography system in evaluating the anterior structures of the human eye. Cornea 2003;22:118-21.  Back to cited text no. 38
    
39.
Suzuki S, Suzuki Y, Iwase A, Araie M. Corneal thickness in an ophthalmologically normal Japanese population. Ophthalmol 2005;112:1327-36.  Back to cited text no. 39
    
40.
Shimmyo M, Ross AJ, Moy A, Mostafavi R. Intraocular pressure, goldmann applanation tension, corneal thickness, and corneal curvature in Caucasians, Asians, Hispanics, and African Americans. Am J Ophthalmol 2003;136:603-13.  Back to cited text no. 40
    
41.
Hahn S, Azen S, Mei YL, Varma R. Los Angelos Latino eye study group. Central corneal thickness in Latinos. Invest Ophthalmol 2003;44:1508-12.  Back to cited text no. 41
    
42.
Foster PJ, Alsbirk PH, Baasanhu J, Munkhbayar D, Uranchimeg D, Johnson GJ. Anterior chamber depth in Mongolians: Variation with age, sex, and method of measurement. Am J Ophthalmol 1997;124:53-60.  Back to cited text no. 42
    
43.
Shufelt C, Fraser-Bell S, Ying-Lai M, Torres M, Varma R; Los Angeles Latino Eye Study Group. Refractive error, ocular biometry, and lens opalescence in an adult population: The Los Angeles Latino eye study. Invest Ophthalmol Vis Sci 2005;46:4450-60.  Back to cited text no. 43
    
44.
Klein AP, Suktitipat B, Duggal P, Lee KE, Klein R, Bailey-Wilson JE, et al. Heritability analysis of spherical equivalent, axial length, corneal curvature, and anterior chamber depth in the beaver dam eye study. Arch Ophthalmol 2009;127:649-55.  Back to cited text no. 44
    
45.
Wickremasinghe S, Foster PJ, Uranchimeg D, Lee PS, Devereux JG, Alsbirk PH, et al. Ocular biometry and refraction in Mongolian adults. Invest Ophthalmol Vis Sci 2004;45:776-83.  Back to cited text no. 45
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed764    
    Printed36    
    Emailed0    
    PDF Downloaded22    
    Comments [Add]    

Recommend this journal