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ABSTRACT: The goal of this study was to describe the normal values of corneal endothelial cell density and hexagonality in healthy rabbits' eyes using contact specular microscopy. Both eyes of 18 rabbits, males and females, of different ages were evaluated. The eyes were divided into three groups of 12 each according to the age range of the animals: G1 (6 months old), G2 (12 months old), and G3 (48 months old). Parameters studied included mean endothelial cell density and hexagonality. For Group I, the mean cell density was 2307 cells per mm2. For GII, the mean cell density was 1895 cells per mm2. For G III, the mean cell density was 1818 cells per mm2. Cell density decreased significantly with aging (P<0.001) among the three groups. Pleomorphism in the rabbits of GI was 74.33±10.08. In the rabbits of GII it was 71.83±11.38. In the rabbits of GIII it was 64.02±28.80. Significant differences (P<0.001) were evident between GI and GIII and GII and GIII but not between Groups I and II. The results showed a decrease in number of cells and hexagonality with aging. Corneal endothelium of rabbits suffers changes due to advancing age both in terms of cell density and morphology.
RESUMO: Objetivou-se avaliar a densidade celular e a hexagonalidade do endotélio da córnea de coelhos saudáveis usando um microscópio especular de contato. Os dois olhos de 18 coelhos, machos ou fêmeas, de diferentes idades foram avaliados. Os olhos foram separados em três grupos de 12 olhos cada em função da idade: G1 (6 meses de idade), G2 (12 meses de idade) e G3 (48 meses de idade). Os parâmetros estudados incluíram a densidade celular e a hexagonalidade. Para o Grupo I, a densidade celular média foi de 2307 células por mm2. Para GII, a densidade celular média foi de 1895 células por mm2. Para G III, a densidade celular média foi de 1818 células por mm2. A densidade celular diminuiu significativamente com o envelhecimento (P<0,001) entre os três grupos. O pleomorfismo nos coelhos de GI foi de 74,33±10,08. Nos coelhos do GII foi 71,83±11,38. Nos coelhos de GIII foi de 64,02±28,80. Diferenças significativas (P<0,001) foram evidentes entre GI e GIII e GII e GIII, mas não entre os Grupos I e II. Os resultados revelaram diminuição da densidade celular e da hexagonalidade com o avanço da idade. O endotélio da córnea de coelhos sofre alterações devido ao avanço da idade tanto na densidade celular e quanto na morfologia.
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Background & objectives: Endothelial cells of the donor cornea are known to be affected quantitatively and qualitatively in different pathological conditions after penetrating keratoplasty (PK) and this has direct effect on the clarity of vision obtained after PK. This study was undertaken to analyze the qualitative and quantitative changes in donor endothelial cells before and after PK in different pathological conditions. Methods: A prospective investigational analysis of 100 consecutive donor corneas used for penetrating keratoplasty between June 2006 and June 2008, was conducted. The patients were evaluated on the first day, at the end of first week, first month, third and six months and one year. Results: A decrease was observed in endothelial cell count in all pathological conditions. After one year of follow up the loss was 33.1 per cent in corneal opacity, 45.9 per cent in acute infective keratitis (AIK), 58.5 per cent in regrafts, 28.5 per cent in pseudophakic bullous keratopathy (PBK), 37 per cent in descemetocele, 27 per cent in keratoconus and 35.5 per cent in aphakic bullous keratopathy (ABK) cases. Interpretation & conclusions: The endothelial cell loss was highest in regraft cases which was significant (P<0.05), while the least endothelial cell loss was seen in keratoconus cases. The cell loss was associated with increase in coefficient of variation (CV), i.e. polymegathism and pleomorphism. Inspite of this polymegathism and pleomorphism, the clarity of the graft was maintained.
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Background Accurate measurement of corneal thickness is very important during the pre-and post-operative management of corneal surgical procedures,especially laser-assisted in-situ keratomileusis (LASIK),which is the most popular approach to the correction of refractive errors currently.This may be particularly important for the patients who have undergone previous laser refractive surgery with suboptimal outcomes and are being considered for an enhancement procedure.Objective This study was to compare the measuring outcomes of corneal thickness by slit-scanning pachymetry,non-contact specular microscope,anterior segment optical coherence tomography (AS-OCT)and ultrasound pachymetry,with a focus on central and midperipheral (from the central 3.0 mm) region of cornea in post-LASIK eyes.Methods Sixty-four right eyes of 64 patients who received LASIK were collected in Henan Eye Institute,Henan Eye Hospital from March to June 2011 with the equivalent spherical diopter of (-4.75±2.38)D and horizontal corneal diameter of (11.36±0.32)mm.Central corneal thickness was measured on each eye by using non-contact specular microscope (Topcon SP-3000P),slit-scanning pachymetry (Orbscan Ⅱ),AS-OCT and A-type ultrasound pachymetry,respectively,and the paracentral corneal thickness including 12:00,2:00,6:00 and 10:00 meridian was measured using Orbscan Ⅱ,non-contact specular microscope and AS-OCT.The measuring values and the agreement from different instruments were compared and evaluated.Results The mean central corneal thickness was (467.12±31.10)tμm for AS-OCT,(466.67±30.99)μm for ultrasound pachymetry,(441.84 ± 33.65) μm for specular microscopy and (422.51 ± 44.09) μm for Orbsan Ⅱ,respectively,showing a significant difference among the four methods (F =23.730,P =0.000).The central thickness value of the A-type ultrasound pachymetry was significantly higher than that of Orbsan Ⅱ or non-contact specular microscope (q =6.940,6.720,both at P =0.000).Compared with Orbscan Ⅱ,the measuring values of non-contact specular microscope and AS-OCT were significantly higher (q =-5.54,6.940,both at P =0.000),and the measuring value of AS-OCT was significantly higher that of non-contact specular microscope (q =6.800,P =0.000).The lowest difference value (25.3 μm)and the best agreement was found between the ultrasound pachymetry and AS-OCT.The paracentral corneal thickness values in 12:00,2:00,10:00,6:00 meridians were highest for Orbsan Ⅱ and the next for AS-OCT,and non-contact specular microscope had the lowest values,with significantly differences among them (F =5.020,22.950,67.890,18.850,all at P ＜ 0.01).Conclusions The corneal thickness values vary with the different instruments.Orbsan Ⅱ underestimates the central corneal thickness and overestimates the midperipheral corneal thickness,and non-contact specular microscope underestimates both the central and midperipheral corneal thickness.The measuring outcome from AS-OCT has a good agreement with ultrasound pachymetry and therefore they can be used interchangeably.
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Background Clinical research showed that the corneal endothelial cell density value from different corneal specula microscopies exist diversity.The relevant literature of SP02,Tomey EM-3000 and SP3000P is still seldom up to now. Objective This research was to assess the repeatability of endothelial cell density measurements by SP02,Tomey EM-3000 and SP3000P respectively and the agreement among 3 kinds of endothelial microscopes.MethodsFifty-four healthy volunteers with the age 17-38 years old were included this research.The written informed consent was obtained from each subject before examination.The corneal endothelial cell densities in the right eyes were analyzed with SP02,Tomey EM-3000 and SP3000P respectively for 3 times under the automatic mode,and the analytical procedure of SP3000P measurement were divided into automatic mode SP3000P (A) and manual correction modes SP3000P( M).The repeatability of each specula microscopy was analyzed by calculating the intraclass correlation coefficients (ICC) and coefficient of variation ( CV ),and the 95％ confidence intervals and plotting Bland-Altman graphs were used to analyze the agreement among these methods.ResultsThe mean corneal endothelial cell densities in the population ＜24 years were significantly higher than the ones ≥ 24 years (t =3.692,P＜0.05 ),but no statistical difference was found between different gender ( t =0.335,P =0.739 ).The mean corneal endothelial cell densities were ( 3058 ± 260 ),( 2954 ± 229 ),( 2668 ± 258 ),( 2734 ± 268 ) cell/mm2 ; the ICCs were 0.957,0.940,0.972 and 0.972 and the CV were 0.063,0.061,0.056,0.058 for SP02,Tomey EM-3000,SP3000P (A) and SP3000P ( M ) respectively.The 95％ confidence intervals were ( - 100.8 - 306.8 ),( 162.6 - 617.4 ),( 109.9-494.1 ) and ( -0.6 - 132.6 ) cell/mm2 for between SP02 and Tomey EM-3000,SP3000P ( A ) and SP02,SP3000P(A) and Tomey EM-3000,SP3000P(A) and SP 3000P(M) respectively.ConclusionsSP02,Tomey EM-3000 and SP3000P(A) have good repeatability in the measurement of corneal endothelial cell density,however the outcome is different.Therefore,it is not interchangeable for the detection of corneal endothelial cell density.The differences of corneal endothelial cell density obtained from these instruments shall be paid high attention for their differences.SP3000P(A) and SP3000P(M) can be used interehangeably and SP3000P(A) is a preferable choice due to its convenience and quickness.
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PURPOSE: To evaluate the corneal thickness values before and after refractive keratoplasty with the Topcon SP-2000 noncontact specular microscope(Topcon American Corp.) and the common standard ultrasonic pachymeter. METHODS: Corneal thickness was measured in 40 eyes of 20 patients, 5 times each before and after keratoplasty, with the Topcon SP-2000P and an ultrasonic pachymeter (DGH 1000, DGH Technology Inc.). The main outcome measures were accuracy and reproducibility as assessed with coefficient of variation (CV) of corneal thickness measurements. RESULTS: The reproducibility of corneal thickness measurements was better with the ultrasonic pachymeter (CV 0.36%) than with the Topcon SP-2000 (CV 1.23%). Mean corneal thickness measured by the Topcon SP-2000P before and after keratoplasty was significantly less than the mean values obtained with the ultrasonic pachymeter (14.4 micro meter; P<.0001, 5.6 micro meter; P<.01; respectively). Compared with theoretical ablated corneal thickness, ablated corneal thickness measured with the Topcon SP-2000P was significantly less (P<.01) than values obtained with the ultrasonic pachymeter (P=0.07) CONCLUSIONS: The noncontact Topcon specular microscope provides measurements of corneal thickness that are significantly less than those of the ultrasonic pachymeter, both before and after keratoplasty. These results indicate that these 2 techniques are not clinically comparable, thereby precluding interchangeable use of their data in planning or assessing keratoplasty.
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Humans , Corneal Pachymetry , Corneal Transplantation , Outcome Assessment, Health Care , UltrasonicsABSTRACT
When the corneal endothelium is injured by intraocular surgery, corneal edema occurs above the threshold level. Preoperative examination of corneal endothelium is valuable in prediction the degree of transparency of the cornea. We conducted this study to elucidate what factors affect corneal endothelial cells in performing the cataract extraction and IOL insertion and what is necessary to minimize the corneal endothelial damage. We performed pacoemulsification and IOL insertion in guttata patients, and preoperative and postoperative endothelial examination was done by using specuar microscope and pachymeter. Although the mean of endothelial cell density was diminished from 1498.7cells/mm2 to 1301cells/mm2 after operation. visible edema was not detected by slit lamp examination and visual acuity was improved from 0.15 to 0.48. The older the patient`s age, the longer the time of phaceemulsification; as the ages of the patients are increased, postoperative corneal thicknesses were increased and postoperative endothelial cell densities were decreased. The endothelial cells were relatively well preserved after cataract operation in patients of preoperative diminished endothelial cells. We suggest that when performing the cataract operation in patients of decreased endothelial function, one must use appropriate large amount of viscoelastic substances, and minimize phacoemulsification power and time in as short operation time as possible by accurate surgical technique. We also believe that periodic postoperative endothelial examination is necessary in patients with decreased endothelial function.
Subject(s)
Humans , Cataract Extraction , Cataract , Cornea , Corneal Edema , Edema , Endothelial Cells , Endothelium, Corneal , Phacoemulsification , Viscoelastic Substances , Visual AcuityABSTRACT
The normal corneal endothelial cell count was measured by the non-contact(Nikon, AS-1, Japan) and contact type(Bio-optic, LSM 2000, USA) specular microscopy. The results of two types were compared to investigate the possible differences in types of specular microscopy. No statistically significant differences were found between the results from the non-contact type and those from the contact type; the mean number of normal Korean corneal endothelial cells according to the age was 2795 in the 2nd decade, 2615 in the 3rd decade, 2463 in the 4th decade, 2283 in the 5th decade, 2119 in the 6th decade, 2019 in the 7th decade and 1920 over the 8th decade.