OBJECTIVETo study the tear film function of patients with type 2 diabetes and to investigate the risk factors of dry eye in these patients.

METHODSTotally 111 patients with type 2 diabetes and 100 age- and sex-matched control subjects were studied. Tear film function was evaluated by dry eye syndrome, tear breaking up time (BUT), corneal fluorescein staining, Schirmer I test (SIt), and tear film lipid layer observation with tear scope. Dye eye score was calculated with the results of these tests.

RESULTSWhen compared with the controls, patients with type 2 diabetes showed higher dry eye score (diabetics 3.28 +/- 1.56, control 2.31 +/- 1.50, P < 0.01) and faster BUT [diabetics (6.50 +/- 4.84) s, control (12.26 +/- 7.16) s, P < 0.01], but similar SIt [diabetics (10.61 +/- 6.86) s, control (10.92 +/- 7.05) s, P > 0.05]. More diabetic patients were diagnosed as dry eye(diabetics 19.8%, control 8.0%, P < 0.05). According to their retinopathy, the diabetic patients were divided into three groups: without diabetic retinopathy (DR), with background DR, and with proliferative DR. For these three groups, the dry eye scores were 2.95 +/- 1.50, 3.38 +/- 1.48 and 4.11 +/- 1.60, respectively (P < 0.01); the SIt were (10.95 +/- 6.89) mm, (11.71 +/- 7.30) mm and (7.63 +/- 5.20) mm, respectively (P > 0.05); the BUT were (7.53 +/- 5.23) s, (5.88 +/- 4.10) s and (4.47 +/- 4.17) s (P < 0.05). Patients with DR were then devided into two groups: with photocoagulation and without photocoagulation. For these two groups, the dry eye scores were 4.71 +/- 1.14 and 3.26 +/- 1.15, respectively (P < 0.01); the BUT were (2.93 +/- 2.06) s and (6.26 +/- 4.36) s, respectively (P < 0.01); the SIt were (7.21 +/- 6.51) mm and (11.33 +/- 6.73) mm, respectively (P < 0.05); the rates of corneal fluorescein staining were 50.0% and 17.9%, respectively (P < 0.05). Dry eye score had a good correlation with diabetic retinopathy and photocoagulation (P < 0.01), but was poorly correlaed with age, gender, insulin, duration of diabetes mellitus, and metabolic control (P > 0.05).

CONCLUSIONSPatients with type 2 diabetes tend to develop tear film dysfunction. The disorders of tear film quantity and quality seem relevant to the stage of diabetic retinopathy and photocoagulation.

Adult ; Aged ; Cornea ; physiopathology ; Diabetes Mellitus, Type 2 ; complications ; physiopathology ; Diabetic Retinopathy ; complications ; physiopathology ; Dry Eye Syndromes ; complications ; physiopathology ; Female ; Humans ; Light Coagulation ; Male ; Middle Aged ; Tears ; secretion

Under the postulation that the double Ruiz procedure could increase the effect of radial keratotomy (RK), RK combined with horizontal and vertical Ruiz procedure was performed in three groups of 22 rabbit eyes. In the group A of six eyes, RK with vertical Ruiz procedure was performed, and eight weeks later horizontal Ruiz procedure was added. In the group B of eight eyes, RK with horizontal Ruiz procedure was performed, and four weeks later vertical Ruiz procedure was added. In the group C of eight eyes, RK with horizontal and vertical Ruiz procedure was performed simultaneously. As a control, in the group D of eight eyes, RK without Ruiz procedure performed. Changes in keratometry for four weeks and eight weeks postoperatively were analyzed. The results were as follows: 1. At eight weeks postoperatively, mean changes in keratometry were 6.434D, 3.663D, 4.030D and 1.585D in groups A, B, C and D, respectively. 2. Mean changes in keratometry of groups A, B and C were significantly higher than that of group D. 3. Mean changes in keratometry of 6.434D in group A was significantly the highest of the three groups in which double Ruiz procedure was performed. For the above results, it was concluded that double Ruiz procedure increased the effect of RK, and the procedure was more effective when the secondary Ruiz procedure was added eight weeks later.
Animals ; Astigmatism ; Cornea/*pathology/physiopathology ; Keratotomy, Radial/adverse effects/*methods ; Rabbits ; Time Factors

The role of nitric oxide (NO) in ocular surface diseases remains unknown. We investigated the conditions leading to increase NO generation in tears and the main sources of ocular surface tissue. We evaluated the possibility of a dual action (cell survival or cell death) depending on the amount of NO. The concentration of nitrite plus nitrate, the stable end-product of NO, was measured in the tears of various ocular surface diseases. We also examined the main source of nitric oxide synthase (NOS) using immunohistochemical staining & Western blot analysis. When cultured human corneal fibroblasts were treated with NO producing donor with or without serum, the viability of cells was studied. We found that sources of NO in ocular surface tissue primarily included corneal epithelium, fibroblasts, endothelium and inflammatory cells. Three forms of NOS (eNOS, bNOS, & iNOS) were expressed in experimentally induced inflammation. Cell death by NO revealed TUNEL positive staining, however in the EM finding, this NO specific cell death was an atypical necrosis showing perinuclear large vacuolization and mitochondrial swelling. In the fibroblasts culture system, the NO donor (SNAP, S-nitroso-N-acetyl-D, L-penicillamine) prevented the death of corneal fibroblasts caused by serum deprivation in a dose dependent manner up to 500 m SNAP, although a higher dose decreased cell viability. This study suggested that NO might act as a double-edged sword in ocular surface disease depending on the degree of inflammatory condition related with NO concentration.
Animal ; Cells, Cultured ; Cornea/metabolism ; Eye Diseases/*physiopathology ; Human ; Nitric Oxide/*metabolism ; Tears/metabolism

The biomechanical properties of 21 white New Zealand rabbits' corneas after Laser in situ keratomileusis (LASIK) were tested by use of one-dimension tensile test and creep test in the INSTRON 5544 mechanical machine. The cornea-related data from the experiments of one-dimension tensile test and creep test for an hour were obtained; a standard linear solid model was adopted to analyse the data, and the least square method was used to fit the viscoelastical coefficients of creep experiment on different corneas. We noticed there was certain difference between the LASIK groups and the normal group in respect to the corneal modulus of elasticity, the stiffness coefficients diminished with the increase of ablation depth; the anti-tensile ability of corneas also displayed some reduction. These findings indicate that the deeper the ablation goes, the easier will be the deformation after LASIK.
Animals ; Biomechanical Phenomena ; Cornea ; physiopathology ; surgery ; Elasticity ; Keratomileusis, Laser In Situ ; methods ; Lasers, Excimer ; therapeutic use ; Rabbits

To determine if the involuntary contractions of eyelids may have any effects on the development of corneal astigmatism, we performed this prospective study which includes 19 patients with either essential blepharospasm or hemifacial spasm. In hemifacial spasm, the degree of corneal astigmatism was evaluated between two eyes. Then the topographic changes were checked using vector analysis technique before and after passively opening the eyelids. They were also measured before and at 1 and 6 months after the injection of Botulinum toxin. Resultantly, 20 eyes had the with-the-rule (group1) and 9 eyes against-the-rule (group2) astigmatism. In hemifacial spasm, significantly more astigmatism was found at spastic eyes. The corneal topographic changes after passively opening the eyelids showed 10 eyes with the astigmatic shift to the with-the-rule, while the remaining 19 to the againstthe- rule. At 1 month after injection of Botulinum toxin, group 1 showed reduced average corneal astigmatism, whereas group 2 showed increased astigmatism. The astigmatic change vector showed significantly more against-the-rule. In the contrary, 6 months after treatment, corneal astigmatism again increased in group 1 and decreased in group 2. So they took on the appearance of pretreatment astigmatic status eventually. Conclusively eyelids may play an important role in corneal curvature.
Aged ; Astigmatism/*drug therapy/physiopathology ; Blepharospasm/*drug therapy/physiopathology ; Botulinum Toxin Type A/administration & dosage/*therapeutic use ; Cornea/drug effects/physiopathology ; Corneal Diseases/*drug therapy/physiopathology ; Eyelids/drug effects/physiopathology ; Female ; Humans ; Injections ; Male ; Middle Aged ; Time Factors ; Treatment Outcome

OBJECTIVETo evaluate the static and dynamic contrast sensitivity changes in myopic patients before and after laser in situ keratomileusis (LASIK).

METHODSSeventy-three eyes in 37 patients with myopia (with or without astigmatism) who received LASIK were tested for static and dynamic contrast sensitivities using the METRO VISION MON ELEC I system at 0.7, 1.4, 2.7, 5.5, 11, and 22 cpd and cps prior to LASIK, and at one-, three-, and six-month intervals after LASIK.

RESULTSAll eyes gained naked visual acuity of more than 0.5 after LASIK. The contrast sensitivity was depressed at all frequencies 1 month after LASIK, as compared to one week prior to LASIK. The depression at 2.7, 5.5, 11 (P < 0.01) and 22 cpd (P < 0.05) was statistically significant for static contrast sensitivity, and also at 5.5 (P < 0.01) and 11 cps (P < 0.05) for dynamic contrast sensitivity. Myopic eyes between 6.25 D and 14.0 D, and astigmatic eyes 2 DC and more, suffered more static and dynamic contrast sensitivity depression than the myopic eyes between 1.25 D and 6.00 D and astigmatic eyes less than 2 DC. Contrast sensitivities were improved and exceeded preoperative levels 3 months after LASIK, and improved even more 6 months after LASIK. All sequences were statistically significant for static contrast sensitivity (P < 0.01), while only 2.7, 5.5, and 11 cps were statistically significant for dynamic contrast sensitivity (P < 0.01). The astigmatic eyes 2 DC and more showed less improvement, even below the preoperative level at 1.4 cps of dynamic contrast sensitivity.

CONCLUSIONSWhile temporary depression of contrast sensitivity for myopic eyes after LASIK was seen, contrast sensitivity soon returned to exceed preoperative levels at 3 months after LASIK, while improving even more 6 months after LASIK.

Adolescent ; Adult ; Astigmatism ; surgery ; Contrast Sensitivity ; Cornea ; surgery ; Female ; Humans ; Keratomileusis, Laser In Situ ; Male ; Myopia ; physiopathology ; surgery ; Visual Acuity

PURPOSE: To describe the characteristics and investigate the differences of higher-order aberrations (HOAs) between the eyes with a natural, uncorrected visual acuity (UCVA) of 20/12 and eyes with highly myopic eyes in Korean adults. METHODS: Thirty-one eyes of 20 subjects with UCVA of 20/12 (Group 1) and 54 eyes of 36 myopic patients with greater than -6 diopters (Group 2) were analyzed for type and magnitude of HOAs across a 6.0 mm pupil. HOAs were measured by Wavescan (VISX, Santa Clara, CA, USA) in natural scotopic conditions and were presented as root-mean-square (RMS: micrometer) in Belle aberration maps. RESULTS: The mean spherical equivalent (SE) of manifest refraction was -0.15+/-0.25 D (range: +0.37 to -0.50 D) in Group 1 and -7.25+/-0.78 D (range: -6.00 to -9.25 D) in Group 2. The total root-mean-square (RMS) values of HOAs for Group 1 and Group 2 were 0.28+/-0.09 micrometer and 0.27+/-0.087 micrometer, respectively (P>0.05). The mean values of coma, trefoil, and spherical aberration were 0.14+/-0.091 micrometer, 0.14+/-0.089 micrometer, 0.091+/-0.059 micrometer in Group 1 and 0.16+/-0.077 micrometer, 0.14+/-0.073 micrometer, 0.082+/-0.059 micrometer in Group 2, respectively. CONCLUSIONS: This study helped establish ocular aberration standards for those with natural supervision and those with highly myopic eyes among Koreans. Individuals with natural supervision had significant amounts of HOAs, and there was no significant difference in the amount of HOAs between the two groups. The index of higher-order aberrations may not be a perfect predictor of the amount of refractive error.
Adult ; Cornea/*physiopathology ; Diagnostic Techniques, Ophthalmological ; Female ; Humans ; Korea/epidemiology ; Male ; *Myopia/diagnosis/epidemiology/physiopathology ; Prevalence ; *Refraction, Ocular ; Severity of Illness Index ; Surface Properties ; Visual Acuity

PURPOSE: To describe the characteristics and investigate the differences of higher-order aberrations (HOAs) between the eyes with a natural, uncorrected visual acuity (UCVA) of 20/12 and eyes with highly myopic eyes in Korean adults. METHODS: Thirty-one eyes of 20 subjects with UCVA of 20/12 (Group 1) and 54 eyes of 36 myopic patients with greater than -6 diopters (Group 2) were analyzed for type and magnitude of HOAs across a 6.0 mm pupil. HOAs were measured by Wavescan (VISX, Santa Clara, CA, USA) in natural scotopic conditions and were presented as root-mean-square (RMS: micrometer) in Belle aberration maps. RESULTS: The mean spherical equivalent (SE) of manifest refraction was -0.15+/-0.25 D (range: +0.37 to -0.50 D) in Group 1 and -7.25+/-0.78 D (range: -6.00 to -9.25 D) in Group 2. The total root-mean-square (RMS) values of HOAs for Group 1 and Group 2 were 0.28+/-0.09 micrometer and 0.27+/-0.087 micrometer, respectively (P>0.05). The mean values of coma, trefoil, and spherical aberration were 0.14+/-0.091 micrometer, 0.14+/-0.089 micrometer, 0.091+/-0.059 micrometer in Group 1 and 0.16+/-0.077 micrometer, 0.14+/-0.073 micrometer, 0.082+/-0.059 micrometer in Group 2, respectively. CONCLUSIONS: This study helped establish ocular aberration standards for those with natural supervision and those with highly myopic eyes among Koreans. Individuals with natural supervision had significant amounts of HOAs, and there was no significant difference in the amount of HOAs between the two groups. The index of higher-order aberrations may not be a perfect predictor of the amount of refractive error.
Adult ; Cornea/*physiopathology ; Diagnostic Techniques, Ophthalmological ; Female ; Humans ; Korea/epidemiology ; Male ; *Myopia/diagnosis/epidemiology/physiopathology ; Prevalence ; *Refraction, Ocular ; Severity of Illness Index ; Surface Properties ; Visual Acuity

PURPOSE: To compare changes of anterior corneal aberration (Pentacam(R)) and ocular aberration (aberrometer, LADARWave(R)) after laser refractive surgery. METHODS: Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam(R) and an aberrometer (LADARWave(R)) respectively. Changes of root mean square (RMS) values of coma, spherical aberration, and total high order aberration (HOA) were evaluated before, 1 month, and 3 months after surgery RESULTS: Ocular aberrations displayed low preoperative values, but after laser refractive surgery, anterior corneal aberration and ocular aberration increased equally. There were no statistically significant differences of internal optics aberration values (ocular aberration minus anterior corneal aberration) in coma, spherical aberration, and total HOA. Anterior corneal aberration and ocular aberration showed statistically significant correlations at 1 and 3 months after surgery. CONCLUSIONS: Internal optics aberration compensated the anterior corneal aberration effectively before surgery, but the increase of anterior corneal aberration after laser refractive surgery exceeded the compensation of internal optics. As a result, anterior corneal aberration and ocular aberration increased equally. The correlation between anterior corneal aberration and ocular aberration after surgery was statistically significant due to the increased proportion of anterior corneal aberration in ocular aberration.
Adult ; Cornea/*physiopathology ; Corneal Topography ; Humans ; Lasers, Excimer/*therapeutic use ; Myopia/surgery ; Photography ; Refraction, Ocular/*physiology ; Refractive Errors/*physiopathology ; *Refractive Surgical Procedures ; Retrospective Studies

PURPOSE: To investigate the relationship between higher-order aberrations (HOAs) and amblyopia treatment in children with hyperopic anisometropic amblyopia. METHODS: The medical records of hyperopic amblyopia patients with both spherical anisometropia of 1.00 diopter (D) or more and astigmatic anisometropia of less than 1.00 D were reviewed retrospectively. Based on the results of the amblyopia treatment, patients were divided into two groups: treatment successes and failures. Using the degree of spherical anisometropia, subjects were categorized into mild, moderate, or severe groups. Ocular, corneal, and internal HOAs were measured using a KR-1W aberrometer at the initial visit, and at 3-month, 6-month, and 12-month follow-ups. RESULTS: The results of the 45 (21 males and 24 females) hyperopic anisometropic amblyopia patients who completed the 12-month follow-up examinations were analyzed. The mean patient age at the initial visit was 70.3 months. In total, 28 patients (62.2%) had successful amblyopia treatments and 17 patients (37.8%) failed treatment after 12 months. Among the patient population, 24 (53.3%) had mild hyperopic anisometropia and 21 (46.7%) had moderate hyperopic anisometropia. When comparing the two groups (i.e., the success and failure groups), ocular spherical aberrations and internal spherical aberrations in the amblyopic eyes were significantly higher in the failure group at every follow-up point. There were no significant differences in any of the HOAs between mild and moderate cases of hyperopic anisometropia at any follow-up. When the amblyopic and fellow eyes were compared between the groups there were no significant differences in any of the HOAs. CONCLUSIONS: HOAs, particularly ocular spherical aberrations and internal spherical aberrations, should be considered as reasons for failed amblyopia treatment.
Aged ; Amblyopia/complications/physiopathology/*therapy ; Anisometropia/complications/physiopathology/*therapy ; Cornea/*pathology/physiopathology ; *Eyeglasses ; Female ; Follow-Up Studies ; Humans ; Hyperopia/complications/physiopathology/*therapy ; Male ; Middle Aged ; Refraction, Ocular/*physiology ; Retrospective Studies ; Treatment Outcome ; *Visual Acuity