Biomedical subjects

Lihui Luo

Publications and source records attributed to Lihui Luo.

14 recordsLinked to original sources

PubMed2005

JNK and ERK MAP kinases mediate induction of IL-1beta, TNF-alpha and IL-8 following hyperosmolar stress in human limbal epithelial cells.

Hyperosmolarity has been recognized to be a pro-inflammatory stress to the corneal epithelium. The cell signalling pathways linking hyperosmolar stress and inflammation have not been well elucidated. This study investigated whether exposure of human limbal epithelial cells to hyperosmotic stress activates the mitogen-activated protein kinase (MAPK) pathways and induces production of pro-inflammatory cytokines, interleukin (IL) -1beta, tumor necrosis factor (TNF) alpha, and the C-X-C chemokine IL-8. Primary human limbal epithelial cultures in normal osmolar media (312 mOsM) were exposed to media with higher osmolarity (400-500 mOsM) by adding 50-90 mM NaCl, with or without SB202190, an inhibitor of c-Jun N-terminal kinases (JNK) pathway, PD 98059, an inhibitor of extracellular-regulated kinase (ERK) pathway, dexamethasone or doxycycline for different lengths of time. The conditioned media were collected after 24 hr of treatment for ELISA. Total RNA was extracted from cultures treated for 6 hr for semi-quantitative RT-PCR. Cells treated for 15-60 min were lysed in RIPA buffer and subjected to Western blot with phospho (p)-specific antibodies against p-JNK and p-ERK. The concentrations of IL-1beta, TNF-alpha and IL-8 proteins in 24 hr conditioned media of limbal epithelial cells progressively increased as the media osmolarity increased from 312 to 500 mOsM. Active p-JNK-1/p-JNK-2 and p-ERK-1/p-ERK-2 were detected by Western blot and peaked at 60 min in cells exposed to hyperosmolar media. The levels of p-JNK-1/p-JNK-2 and p-ERK1/p-ERK2 were positively correlated with the medium osmolarity. SB202190, PD98059 and doxycycline markedly suppressed the levels of p-JNK-1/p-JNK-2 and/or p-ERK1/p-ERK2, as well as IL-1beta, TNF-alpha and IL-8 mRNAs and proteins stimulated by hyperosmolar media. These findings provide direct evidence that hyperosmolarity induces inflammation in human limbal epithelial cells by increasing expression and production of pro-inflammatory cytokines and chemokines, a process that appears to be mediated through activation of the JNK and ERK MAPK signalling pathways. The efficacy of doxycycline in treating ocular surface diseases may be due to its ability to suppress JNK and ERK signalling activation and inflammatory mediator production in the limbal epithelium.

Adult↗

PubMed2005

Matrix metalloproteinase-9 knockout confers resistance to corneal epithelial barrier disruption in experimental dry eye.

Altered corneal epithelial barrier function is the cause for ocular irritation and visual morbidity in dry eye disease. Increased matrix metalloproteinase (MMP)-9 activity has been observed in the tear fluid of dry eye patients. To determine the pathogenic role of MMP-9 in the corneal epithelial disease of dry eye, the effects of experimentally induced dry eye on corneal epithelial morphology and barrier function were compared in MMP-9 knockout mice and their wild-type littermates. Dry eye was created through cholinergic blockade and exposure to a desiccating environment. The tear fluid MMP-9 concentration increased in response to dryness in wild-type mice. Corneal epithelial permeability to three different-sized molecules increased in dry eye wild-type mice, but not in MMP-9 knockout mice. Topical administration of active MMP-9 to dry eye MMP-9 knockout mice significantly increased corneal epithelial permeability. Compared to MMP-9 knockout mice, wild-type mice showed greater desquamation of differentiated apical corneal epithelial cells that expressed the tight junction protein occludin in response to dryness. This was accompanied by an increase in lower sized (50 kd) occludin in the corneal epithelia of wild-type mice. These findings could be replicated in cultured human corneal epithelial cells that were treated with active MMP-9. These studies indicate that increased MMP-9 activity on the ocular surface in response to dryness disrupts corneal epithelial barrier function. This appears to be because of accelerated loss of tight junction bearing superficial corneal epithelial cells, perhaps by proteolytic cleavage of occludin.

Animals↗

PubMed2005

Stress-activated protein kinase signaling pathways in dry eye and ocular surface disease.

Inflammation is recognized as a key component in the pathogenesis of dry eye and a variety of ocular surface diseases. Stress-activated protein kinases have been identified as pathways signaling ocular surface stresses, such as increased tear film osmolarity and ultraviolet light exposure. Activation of these stress pathways results in transcription of stress related genes, including inflammatory cytokines (e.g. interleukin-1 and tumor necrosis factor (TNF)-alpha and matrix metalloproteinases (MMPs), such as MMP-9. Treatment of osmo-stressed cultured corneal epithelia with inhibitors of the stress associated kinase c-jun N-terminal kinases was found to decrease production of MMPs by these cells. These findings suggest that SAPKs may be key therapeutic targets for dry eye and ocular surface diseases.

Journal Article↗

PubMed2005

Hyperosmolar saline is a proinflammatory stress on the mouse ocular surface.

PURPOSE: To investigate whether hyperosmolar stress stimulates production of inflammatory mediators and activates the mitogen-activated protein kinase (MAPK) signaling pathways, c-jun n-terminal kinases (JNKs), extracellular-regulated kinases (ERKs), and p38 on the mouse ocular surface. METHODS: 129SvEv/CD-1 mixed mice were treated with a balanced salt solution (BSS) (305 mOsM) or a hyperosmotic saline solution (HOSS) (500 mOsM). Untreated age-matched mice were used as controls. The concentrations of interleukin 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) were measured by enzyme-linked immunosorbent assay. Gelatinase activity was determined by in situ zymography. Corneal and conjunctival epithelia were lysed for Western blot with MAPK antibodies or used for semiquantitative reverse transcription and polymerase chain reaction and gene array. RESULTS: Compared with age-matched controls and mice treated with BSS, the concentration of IL-1beta in tear fluid washings and the concentrations of IL-1beta and TNF-alpha and gelatinolytic activity in the corneal and conjunctival epithelia were significantly increased in mice treated with HOSS for 2 days. The expressions of IL-1beta, TNF-alpha, and matrix metalloproteinase 9 (MMP-9) messenger RNA by the corneal and conjunctival epithelia were also notably stimulated in mice treated with HOSS. The levels of phosphorylated JNK1/2, ERK1/2, and p38 MAPKs in the corneal and conjunctival epithelia were slightly increased in mice treated with BSS, but markedly increased in mice treated with HOSS. CONCLUSIONS: These results show that the hyperosmolarity stimulates expression and production of IL-1beta, TNF-alpha, and MMP-9 and activates JNK, ERK, and p38 MAPK signaling pathways on the mouse ocular surface. These findings suggest that hyperosmolar stress, as it may occur in dry eye, promotes ocular surface inflammation.

Animals↗

PubMed2005

Altered corneal nerves in aqueous tear deficiency viewed by in vivo confocal microscopy.

PURPOSE: To define the alterations of corneal nerves in aqueous tear deficiency dry eye patients with or without Sjögren syndrome and to identify the relationship between the morphologic changes of corneal nerves and the extent of dry eye. METHODS: Confocal microscopy was used to examine 38 consecutive aqueous tear deficiency patients (8 Sjögren syndrome and 30 non-Sjögren syndrome) and 30 age- and gender-matched normal controls. Images taken by Confocal2 slit-scanning microscope at subbasal epithelial cell layer of central cornea were analyzed. The number and density of corneal nerves and their size, beads, tortuosity, and branching pattern were compared. These data were correlated with age and the degree of dry eye. RESULTS: Sjögren syndrome patients showed a significant increase in average nerve number and tortuosity as compared with normal controls (P = 0.031 and 0.021, respectively). Severe nerve tortuosity (grade 4) and nerve branching appeared more frequently in aqueous tear deficiency than in normal subjects (P = 0.024 and 0.042, respectively). A decreased nerve number was observed with age in the normal controls (P = 0.002). However, such a correlation did not exist in aqueous tear deficiency. In aqueous tear deficiency, rose bengal staining score correlated positively with nerve density (P = 0.048) and nerve number (P = 0.001). Corneal fluorescein staining score was also positively correlated with nerve number (P = 0.027). CONCLUSIONS: Abnormal morphologic changes are observed in aqueous tear deficiency that are more severe in Sjögren syndrome. The distinct changes of corneal nerves include increased nerve number, tortuosity, and chances of branching, suggesting an attempted nerve regeneration. A strong correlation exists between the changes of nerve morphology and the degree of dry eye. These results provide some possible evidence for the abnormal corneal sensation in dry eye.

Adult↗

PubMed2005

Doxycycline inhibits TGF-beta1-induced MMP-9 via Smad and MAPK pathways in human corneal epithelial cells.

PURPOSE: To evaluate the effects of TGF-beta1 and doxycycline on production of gelatinase MMP-9 and activation of Smad, c-Jun N-terminal kinase (JNK), extracellular-regulated kinase (ERK), and p38 mitogen-activated protein kinase (MAPK) signaling pathways in human corneal epithelial cells. METHODS: Primary human corneal epithelial cells were cultured to confluence. The cells were treated with different concentrations of TGF-beta1 (0.1, 1, or 10 ng/mL), with or without TGF-beta1-neutralizing mAb (5 microg/mL), SP600125 (30 microM), PD98059 (40 microM), SB202190 (20 microM), or doxycycline (5-40 microg/mL) for different lengths of time. Conditioned media were collected from cultures treated for 24 to 48 hours to evaluate the MMP-9 production by zymography and activity assay. Total RNA was isolated from cells treated for 6 to 24 hours to evaluate MMP-9 expression by semiquantitative RT-PCR and Northern hybridization. Cells treated for 5 to 60 minutes were lysed in RIPA buffer for Western blot with phospho-specific antibodies against Smad2, JNK1/2, ERK1/2, or p38. RESULTS: TGF-beta1 increased expression, production, and activity of MMP-9 by human corneal epithelial cells in a concentration-dependent fashion. TGF-beta1 also induced activation of Smad2, JNK1/2, ERK1/2, and p38 within 5 to 15 minutes, with peak activation at 15 to 60 minutes. Doxycycline markedly inhibited the TGF-beta1-induced production of MMP-9 and activation of the Smad, JNK1/2, ERK1/2, and p38 signaling pathways. Its inhibitory effects were of a magnitude similar to SP600125, PD98059, and SB202190, specific inhibitors of the JNK1/2, ERK1/2, and p38 pathways, respectively. CONCLUSIONS: These findings demonstrated that doxycycline inhibits TGF-beta1-induced MMP-9 production and activity, perhaps through the Smad and MAPK signaling pathways. These inhibitory effects may explain the reported efficacy of doxycycline in treating MMP-9-mediated ocular surface diseases.

Anti-Bacterial Agents↗

PubMed2005

Plasminogen kringle 5 inhibits alkali-burn-induced corneal neovascularization.

PURPOSE: Plasminogen kringle 5 (K5) is a potent angiogenic inhibitor. The purpose of the present study was to evaluate the therapeutic effect of K5 on alkali-burn-induced corneal neovascularization (NV) and to investigate its mechanism of action. METHODS: Corneal NV was induced in rabbits by NaOH. The rabbits received eye drops containing K5 or vehicle alone, four times per day. Corneal NV and inflammation were monitored every other day with a slit lamp microscope, and the length of the vessels in the cornea and the area of NV were measured. Vascular endothelial growth factor (VEGF) was determined by immunohistochemical and Western blot analyses. The TUNEL assay was used to assess the apoptosis of endothelial cells. The effects of K5 on primary bovine aortic endothelial cells (BAECs) were determined by MTT assay, flow cytometry, transmission electron microscopy, and DNA fragmentation assay. RESULTS: Alkali-burn-induced progressive corneal NV and inflammation in the cornea. K5 delayed the onset of corneal NV (P < 0.05) and decreased NV areas (P < 0.05) in a dose-dependent manner. K5 treatment, after the formation of corneal NV, induced regression of newly formatted vessels in the cornea. K5 decreased the inflammatory index in the corneas at different time points after the alkali burn. Corneal VEGF levels were reduced by K5 treatment. K5 inhibits proliferation and induces apoptosis in BAECs. CONCLUSIONS: Topical application of K5 may have therapeutic potential for the chemical burn-induced corneal NV and inflammation. The inhibitory effect of K5 on corneal NV may be by downregulation of VEGF expression.

Administration, Topical↗

PubMed2004

Experimental dry eye stimulates production of inflammatory cytokines and MMP-9 and activates MAPK signaling pathways on the ocular surface.

PURPOSE: To evaluate whether experimentally induced dry eye in mice activates mitogen-activated protein kinase (MAPK) signaling pathways, c-Jun N-terminal kinases (JNK), extracellular-regulated kinases (ERK), and p38 and stimulates ocular surface inflammation. METHODS: 129SvEv/CD-1 mixed mice aged 6 to 8 weeks were treated with systemic scopolamine and exposure to an air draft for different lengths of time, from 4 hours to 10 days. Untreated mice were used as the control. The concentrations of IL-1beta and TNF-alpha in tear fluid washings and in corneal and conjunctival epithelia were measured by ELISA. MMP-9 in tear washings was evaluated by zymography, and gelatinase activity in the cornea and conjunctiva was determined by in situ zymography. Corneal and conjunctival epithelia were lysed in RIPA buffer for Western blot with MAPK antibodies, or they were lysed in 4 M guanidium thiocyanate solution for extraction of total RNA, which was used to determine gene expression by semiquantitative RT-PCR, real-time PCR, and gene array. RESULTS: Compared with those in age-matched control subjects, the concentrations of IL-1beta and MMP-9 in tear fluid washings and the concentrations of IL-1beta and TNF-alpha and gelatinolytic activity in the corneal and conjunctival epithelia were significantly increased in mice receiving treatments to induce dry eye after 5 or 10 days. The expression of IL-1beta, TNF-alpha, and MMP-9 mRNA by the corneal and conjunctival epithelia was also stimulated in mice treated for 5 or 10 days. The levels of phosphorylated JNK1/2, ERK1/2, and p38 MAPKs in the corneal and conjunctival epithelia were markedly increased as early as 4 hours after treatment, and they remained elevated up to 5 days. CONCLUSIONS: Experimental dry eye stimulates expression and production of IL-1beta, TNF-alpha, and MMP-9 and activates MAPK signaling pathways on the ocular surface. MAPKs are known to stimulate the production of inflammatory cytokines and MMPs, and they could play an important role in the induction of these factors that have been implicated in the pathogenesis of dry eye disease.

Animals↗

PubMed2004

Stimulation of matrix metalloproteinases by hyperosmolarity via a JNK pathway in human corneal epithelial cells.

PURPOSE: To investigate whether exposure of human corneal epithelial cells to hyperosmotic stress activates the c-Jun NH(2)-terminal kinase (JNK) stress-activated protein kinase (SAPK) pathway, and stimulates production of the matrix metalloproteinases (MMPs): gelatinase (MMP-9), collagenases (MMP-1 and -13), and stromelysin (MMP-3). METHODS: Primary human corneal epithelial cells cultured in normal osmolar medium (312 mOsM) were exposed to media with higher osmolarity (350-500 mOsM) achieved by adding NaCl, with or without SB202190, an inhibitor of the JNK pathway; dexamethasone; or doxycycline for different lengths of time. The conditioned media were collected after 24 hours of exposure for zymography and ELISA. Total RNA was extracted from cultures treated for 6 hours and subjected to semiquantitative RT-PCR. Cells treated for 5 to 60 minutes were lysed in RIPA buffer and subjected to Western blot with phospho (p)-specific antibodies against p-JNK and p-c-Jun. JNK1 activation was also detected with an immunoassay system. RESULTS: The concentrations of MMP-9, -1, and -3 proteins in 24-hour conditioned media of corneal epithelial cells progressively increased as the media's osmolarity was increased from 312 to 500 mOsM by the addition of NaCl. The concentration of MMP-13 progressively increased to a peak at 450 mOsM. Active p-JNK-1, p-JNK-2, and p-c-Jun were detected by Western blot as early as 5 minutes and peaked at 60 minutes in cells exposed to hyperosmolar media. The levels of p-JNK-1, p-JNK-2, and p-c-Jun correlated positively with the osmolarity of the culture media. The p-JNK inhibitor SB202190 and doxycycline markedly inhibited the stimulation of p-JNK-1, p-JNK-2, and p-c-Jun, as well as MMP-9, -1, -13, and -3 at both the mRNA and protein levels in the cells exposed to hyperosmolar media. CONCLUSIONS: Expression and production of MMP-9, -1, -13, and -3 by human corneal epithelial cells correlated positively with increasing media osmolarity. This increase was mediated at least in part through activation of the JNK SAPK pathway. Doxycycline, an agent used to treat MMP-mediated ocular surface disease, inhibited the hyperosmolarity-induced MMP production and JNK activation. The relevance of these findings to stimulated production of MMPs by the elevated tear osmolarity in dry eye remains to be determined.

Adolescent↗

PubMed2004

Characterization of putative stem cell phenotype in human limbal epithelia.

This study evaluated proposed molecular markers related to stem cell (SC) properties with the intention of characterizing a putative SC phenotype in human limbal epithelia. Human corneal and limbal tissues were cut in the vertical and horizontal meridians for histology, transmission electron microscopy (TEM), and immunostaining. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization were used to evaluate gene expression. TEM showed that the limbal basal cells were small primitive cells. Immunostaining disclosed that p63, ABCG2 and integrin alpha9 were primarily expressed by the basal epithelial cells of limbus. Antibodies against integrin beta1, epidermal growth factor receptor (EGFR), K19, enolase-alpha, and CD71 stained the basal cells of the limbus more brightly than the suprabasal epithelia. Integrin alpha6, nestin, E-cadherin and connexin 43 did not stain the limbal basal cells, but the suprabasal epithelia of the cornea and limbus showed strong immunoreactivity. K3 and involucrin stained only corneal and limbal superficial cells. RT-PCR showed higher levels of p63, ABCG2 and integrin alpha9 mRNA, but lower levels of K3, K12 and connexin 43 expressed in the limbal epithelia than the corneal epithelia. In situ hybridization showed that p63 transcripts were located in basal layer of the limbal epithelium. This work suggests that the basal epithelial cells of the limbus are p63, ABCG2 and integrin alpha9 positive, and nestin, E-cadherin, connexin 43, involucrin, K3, and K12 negative, with relatively higher expression of integrin beta1, EGFR, K19, and enolase-alpha. This putative SC phenotype may facilitate the identification and isolation of limbal epithelial SCs.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed2003

[Confocal microscopy in transplanted human corneas].

PURPOSE: The aim of the study was in-real time observation and morphological evaluation of the transplanted human corneas, using confocal 2.0 microscopy. METHODS: Twelve eyes of 12 patients on 3-7 days after lamellar keratoplasty (LKP), 8 eyes of 8 patients at 1 year after LKP, and 10 eyes of 10 patients at 3-7 days after penetrating keratoplasty (PKP), 11 eyes of 11 patients at 1 year after PKP were examined by confocal 2.0 microscopy in vivo. Images were recorded by continuously focusing the optical section through the full thickness central cornea. RESULTS: 3-7 days after LKP, small stromal cells, cranny-like dark strias and nerves were seen in transplanted corneas. There were highly reflective regions and dots in the lamellar interface. One year after LKP, the nerves disappeared. There were less highly reflective regions, but the dots still can be seen. Some gross dark strias were seen in the posterior stroma and the density of the endothelium cells was normal. 3-7 days after PKP, keratocytes were activated. Nerves and gross dark strias could be seen in transplanted corneas. The density of the endothelium cells was normal, with some highly reflective dots deposited among them. One year after PKP, the nerves disappeared, and strias still existed. The density of the endothelium cells decreased significantly. CONCLUSIONS: Confocal scanning microscopy is a new tool for the study of cellular morphology and construction of transplanted human corneas. It can be used in the evaluation of operation effect, clinical observation and follow-up.

Adult↗

PubMed2002

[Tear film changes after phacoemulsification].

OBJECTIVE: To evaluate tear film changes after phacoemulsification. METHODS: This prospective randomized study involved 68 consecutive patients with age-related cataract (79 eyes) who underwent phacoemulsification. Tear break-up time, Schirmer I test (S I t) value, corneal fluorescein staining, tear film pattern by DR-1 tear interfermetry and the height of tear meniscus were measured preoperatively and 1 day and 2, 7, 14, 30, 180 days postoperatively. RESULTS: At 1 day and 2 days postoperatively, the mean tear break-up time reduced greatly, and the number of patients who showed III to V tear film pattern, the mean S I t value, the height of tear meniscus and fluorescein staining scores increased significantly (P < 0.001 for day 1, P < 0.005 for day 2). S I t value at 7 days postoperatively (P = 0.831) and the height of tear meniscus at 14 days returned to their preoperative values (P = 1.000). The tear break-up time, corneal fluorescein staining scores and the grades of tear film pattern all recovered at 30 days postoperatively (P > 0.05). At 30 days postoperatively, 19.3% of patients showed shorter tear break-up time and less S I t value than that of preoperative day. In addition, 1/9 of the patients with normal preoperative tear film experienced dry eye at 30 days postoperatively. The cases with tear break-up time < 10 seconds compared to patients with tear break-up time >/= 10 seconds were more easily to show tear instability postoperatively (relative risk 13.5, 8.25, 20.0, 39.0, 8.6, 3.9 at 1 day and 2, 7, 14, 30, 180 postoperative days, respectively). CONCLUSION: Phacoemulsification significantly alters the tear break-up time, S I t value, corneal fluorescein staining, tear film pattern and the height of tear meniscus. Some patients with normal tear film may experience dry eye after surgery. Patients with preexisting tear break-up time < 10 seconds are easily at risk of experiencing the tear film instability postoperatively.

Aged↗

PubMed2002

An experimental study of anti-angiogenesis with recombinant human kringle 5.

OBJECTIVE: To investigate the anti-angiogenesis effects of recombinant human kringle 5 (rhk5) eye drops on corneal neovascularization (CNV) in rabbits induced by alkali burn. METHODS: Forty New Zealand albino rabbits were burned on the central corneas of their right eyes by 1 mol/L NaOH for 60s. Animals were randomly divided into 4 groups, 10 rabbits each group. Then rhk5 eye drops with different concentrations were applied four times daily for four weeks on each group: 5 mg/L in group 1, 10 mg/L in group 2, 20 mg/L in group 3 and carrier solution in group 4 (controls). The occurrence and development of CNV was observed every other day by slit-lamp microscope, and the area of CNV was calculated. Then the rabbits were killed on the 28th day (d), and the corneas were taken for histopathological examinations. Pearson's analysis was used to analyze the correlation between the number of inflammatory cells and the area of CNV. RESULTS: The occurrence of CNV in group 1 was (3.4 +/- 0.5) d, group 2 (6.8 +/- 0.4) d, group 3 (6.7 +/- 0.7) d and group 4 (3.7 +/- 0.5) d. Significant difference (P < 0.05) in the occurrence time of CNV was found between group 2 and the control. Compared with the control group, the CNV occurrence was significantly delayed in the group treated by 10 mg/L rhk5. No significant difference was found between control group and group 1, and between group 2 and group 3. The CNV areas of group 2 and group 3 were also smaller than the control group (P < 0.05). The area of CNV had close relationship with the retrocorneal membrane and with the number of inflammatory cells (P < 0.05). CONCLUSION: Topical application of recombinant human rhk5 has prominent effectiveness on the inhibition of angiogenesis induced by alkali burn.

Angiogenesis Inhibitors↗

PubMed2002

[Corneal topography and thickness in keratoconus].

OBJECTIVE: To evaluate the corneal topography and pachymetry in keratoconus. METHODS: Thirty-five patients (47 eyes) with keratoconus were evaluated by Orbscan corneal topography system. The location, anterior and posterior surface elevation, curvature and pachymetry were analyzed with special reference to the central point of cornea, the apex, the highest point of posterior surface, the point with greatest curvature and the thinnest point. The correlation between the point of greatest curvature and the apex was also analyzed. RESULTS: The mean elevation of the apex was (0.102 +/- 0.044) mm, the mean distance between the apex and the central point of cornea was (0.686 +/- 0.376) mm. Most of the apexes, the points with the highest posterior surface, the points with the greatest curvature were located in the inferior temporal quadrant, followed by inferior nasal, superior temporal and superior nasal quadrant. The SimK of keratocunus was (60.9 +/- 10.4/53.4 +/- 8.7) D and the mean powers within 3 mm and 5 mm were (57.1 +/- 8.0) D and (50.7 +/- 5.4) D respectively. High correlation between apex elevation and the apex curvature was found (r = 0.697, P < 0.01), and there was also negative relationship between apex elevation and corneal thickness (r = -0.563, P < 0.01). CONCLUSIONS: The Orbscan system can provide accurate and subtle information about the shape and thickness of keratoconus, which can help us to learn this disorder deeply, especially in the early diagnosis of this disease.

Adolescent↗