The Effect of Prolactinoma on Tear Film Function.

Objectives: To compare dry eye parameters in prolactinoma patients and healthy controls and evaluate their correlation with prolactin (PRL) levels and the duration of hyperprolactinemia. Materials and Methods: Consecutive patients with prolactinoma and healthy controls were included in the study. Schirmer, tear break-up time (TBUT), tear osmolarity values, and ocular surface disease index (OSDI) scores were evaluated for each patient. Follow-up time and total duration of hyperprolactinemia were recorded for prolactinoma patients. Results: The study included 39 eyes of 39 patients with prolactinoma and 39 eyes of 39 age- and gender-matched healthy controls. Prolactinoma patients showed lower Schirmer (14.1±8.4 vs. 24.8±8.9 mm; p<0.001) and TBUT values (7.0±3.2 vs. 11.6±2.6 s; p<0.001) and higher OSDI scores (20.6±16.6 vs. 5.8±2.4; p<0.001) compared to the healthy controls. While the mean osmolarity of the prolactinoma patients was 301.6±8.3 mOsm/L, it was 297.7±12.5 mOsm/L for the healthy controls (p=0.07). The duration of hyperprolactinemia in prolactinoma patients showed a negative correlation with Schirmer (r=-0.395; p=0.013) and TBUT values (r=-0.377; p=0.018) and a positive correlation with OSDI scores (r=0.337; p=0.036). Conclusion: Prolactinoma patients had significantly lower Schirmer and TBUT levels and higher OSDI scores compared to the healthy controls, but no significant difference in tear osmolarity. The effect of high PRL levels on tear film function was duration-dependent.

Effect of scleral lens use on conjunctival microbiota.

AIM: This study aimed to investigate the effect of scleral lens (SL) use on conjunctival microbiota. METHOD: A total of 26 eyes of 26 patients using an SL and 25 eyes of 25 healthy controls were included in the study. The samples were obtained from the lower fornices of the eyes using sterile swabs. For the bacteriological examination, a bacterial culture was obtained by inoculating the samples on chocolate agar, blood agar, MacConkey agar, and fluid thioglycollate medium. After 24-48 h of incubation at 37 0C, the growth of different colonies of bacteria was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (Bruker MALDI Biotyper). RESULTS: The mean age of the study group was 41.6 ± 19.1 years (18-65); the mean age of the control group was 40 ± 6 (21-62) (p = 0.69). There were 10 male patients and 16 female patients in the study group and 9 male patients and 16 female patients in the control group (p = 0.86). The mean duration of SL use was 13.7 ± 13.4 months (1-42 months). No bacterial growth was observed in 17 (65.4 %) of the 26 eyes in the SL group and 5 (20 %) of the 25 eyes in the control group (p = 0.001). The most commonly observed microorganisms were Staphylococcus epidermidis (S.epidermidis) and Staphylococcus aureus (S.aureus) in both groups. CONCLUSION: SL users were found to have a higher rate of culture negativity in comparison to the healthy controls, suggesting that SLs have a significant effect on conjunctival microbiota.

Efficacy of fixation of the amniotic membrane on a symblepharon ring with continuous suturing in acute ocular chemical burn patients.

PURPOSE: To describe a modified non-traumatic amniotic membrane transplantation (AMT) technique and evaluating its efficiency for the ocular surface injury after chemical burn were aimed. METHODS: Twenty eyes of 20 patients (F: 6, M: 14) with acute chemical burn for whom modified non-traumatic AMT was utilized were evaluated retrospectively. In this technique, amniotic membrane (AM) was fixated onto a symblepharon ring with continuous suturing. The healing time of the corneal epithelial defect due to ocular surface chemical injury and melting duration of AM were evaluated. Development of infection or symblepharon, recurrence or persistence of epithelial defect, corneal perforation and the ring falling out with AM were evaluated as complications. RESULTS: Mean age of the patients was 24.7 ± 11.7 years old (14 months-40 years). Mean duration of applying the non-traumatic AMT after contact with the chemical agent was 8.4 ± 6.2 days (2-21 days). The mean duration of the epithelial defect healing was 27.8 ± 8.8 days (11-40 days) in the grade II, III, and IV (n = 12) cases, while in the grade V and VI (n = 8) cases, a persistent epithelial defect developed, and the mean duration of the epithelial defect healing was 83 ± 23.1 days (42-120 days) (p = 0.0002). The mean melting duration of the AM was 22.7 ± 10 days (10-42 days). CONCLUSION: By using this modified AMT technique, AM can be utilized efficiently, easily, and non-traumatically in every center for the treatment of the ocular surface injury due to chemical burn.

Effect of the Rigid Gas-Permeable Contact Lens Use on the Endothelial Cells in Patients With Keratoconus.

OBJECTIVES: To compare the changes in the corneal endothelial cells of both the patients with keratoconus who use rigid gas-permeable (RGP) contact lens and who do not use any contact lens with healthy population. METHODS: Thirty-three patients with keratoconus who use RGP contact lenses (group 1), 20 patients with keratoconus who do not use any contact lens (group 2), and 40 healthy controls were included in the study. Changes in the corneal endothelial cells of all patients were evaluated using a noncontact specular microscope. Endothelial cell density (ECD), coefficient of variability (CV), hexagonal cell percentage (%HEX), and central corneal thickness (CCT) of the patients were evaluated in the study. RESULTS: In the groups 1, 2, and 3, the mean ECD was 2,420.8±247, 2,579.5±240, and 2,589.5±271 cells/mm, the mean CV was 357±9, 34±7, and 34±6, the mean %HEX was 54.3±13, 59.1±14, and 57.4±10, and the mean CCT was 508±33, 504±43, and 561±34 µm, respectively. There was no significant difference between the groups in terms of ECD, CV, and %HEX. Although significant differences between the groups 1 to 3 and groups 2 to 3 in terms of CCT were detected (P=0.001 and P=0.004, respectively), no significant difference was observed between the groups 1 and 2. CONCLUSIONS: Although significant difference was found between the groups 1 to 2 and normal population in terms of CCT, no difference was detected between all the groups in terms of the other parameters. In this study, we report that long-term use of RGP contact lens in patients with keratoconus had no effect on the corneal endothelial cells.

Treatment of plasminogen deficiency patients with fresh frozen plasma.

Congenital plasminogen (Plg) deficiency leads to the development of ligneous membranes on mucosal surfaces. Here, we report our experience with local and intravenous fresh frozen plasma (FFP). We retrospectively reviewed medical files of 17 patients and their eight first-degree relatives. Conjunctivitis was the main complaint. Thirteen patients were treated both with intravenous and conjunctival FFP. Venous thrombosis did not develop in any. Genetic evaluation revealed heterogeneous mutations as well as polymorphisms. Diagnosis and treatment of Plg deficiency is challenging; topical and intravenous FFP may be an alternative treatment.

Effects of the rigid gas permeable contact lense use on tear and ocular surface among keratoconus patients.

PURPOSE: To investigate changes in tear and ocular surface of patients with keratoconus using rigid gas permeable contact lenses (RGPCL) and compare them against keratoconus patients who were not using lenses as well as a control group of healthy subjects. METHODS: 24 keratoconus patients using RGPCL (Group 1) 22 patients who were not using lenses (Group 3) and 21 healthy subjects (Group 3) were included in the study. Subjective complaints about the subjects' eyes have been investigated using the ocular-surface disease index (OSDI). After the control of best-corrected visual acuity, anterior chamber and fundus examinations were performed. RESULTS: Schirmer (p-value=0.01) and tear break up mean comparison tests (p-value=0.002) revealed significant differences across different groups but tear osmolarity analysis did not (p-value >0.05). Oxford and OSDI scores were compatible with Schirmer and tear break up test comparisons. (for both p-value=0.001) Moreover, no statistical differences were seen in impression cytology measures between groups. (p-value >0.05) CONCLUSIONS: The erosion in the tear film stability is in line with the erosion in the ocular surface epithelium. Taking into account the statistical indifference between the impression cytology measures across groups, the break up time differences may be attributed to the collagen destruction in tear.

A retrospective analysis of vision correction and safety in keratoconus patients wearing Toris K soft contact lenses.

The purpose of this study was to investigate the efficacy and safety of the Toris K silicone hydrogel contact lens (SwissLens; Prilly, Switzerland) in keratoconus patients. A database with information on 50 keratoconus patients (64 eyes) fitted with Toris K soft contact lenses over a 2-year period was retrospectively reviewed. Demographic data, prefitting refraction, the reason for choosing the Toris K soft contact lens, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), best-corrected visual acuity with a rigid gas permeable lens (BCVA RGP), best-corrected visual acuity with the Toris K lens (BCVA Toris K), and complications were evaluated. The mean age ± standard deviation at the time of fitting was 27.92 ± 9.86 years. The mean spherical refractive power was -4.62 ± 6.53 dioptres, and the mean cylinder was -3.78 ± 2.43 dioptres. The most common reason for using Toris K soft contact lenses was an inability to fit the patient with a RGP contact lens. There was a statistically significant difference between UCVA and BCVA Toris K (p = 0.0001), as well as between BSCVA and BCVA Toris K (p = 0.0001). However, there was no statistically significant difference between BCVA Toris K and BCVA RGP (p = 0.20). Superficial punctate keratitis and giant papillary conjunctivitis were the most common complications. The Toris K contact lens is a viable alternative for the optical management of all grades of keratoconus. The Toris K soft contact lens is a promising alternative for the visual rehabilitation of keratoconus patients who cannot tolerate RGP lenses or achieve a good fit.

Comparative Analysis of Tear Film Levels of Inflammatory Mediators in Contact Lens Users.

PURPOSE: To compare tear films levels of various inflammatory cytokines in asymptomatic contact lens (CL) users. CL users of rigid gas-permeable CLs (RGPCL) (group 1) or silicone hydrogel CLs (SiHCL) (group 2) were compared with non-CL-using healthy subjects (group 3). MATERIALS AND METHODS: Tear samples were collected from subjects in each group after ensuring that there were no complications secondary to CL wear in the CL-wearing participants. Tear-film levels of interleukins (ILs)-1ß, -6, and -8; granulocyte-macrophage colony-stimulating factor (GM-CSF) (using the Luminex method); and leukotriene B4 (LTB4) (using the ELISA method) were determined. Cytokine levels were compared among the three groups using analysis-of-variance (ANOVA) and Kruskall-Wallis tests. RESULTS: There were significant differences in concentrations of IL-1ß, GM-CSF and LTB4 among the three groups (p = 0.002, p = 0.021 and p = 0.009, respectively), as shown by the Kruskall-Wallis test comparing all three groups for the three cytokines. There were no significant differences for IL-6 and IL-8 (p = 0.079 and 0.094, respectively) when all three groups were compared. CONCLUSIONS: There were substantial statistically significant differences between RGPCL users, SiHCL users and control subjects in levels of tear film cytokines. Although CL users were asymptomatic, changes in tear-film levels of several important inflammatory mediators revealed that a chronic inflammatory process occurs during CL wear.

Molten metal-related ocular thermal burn: report on two cases.

We report two cases of severe thermal burns on the ocular surface and its adnexal appendages that developed secondary to exposure to molten heavy metal with a melting temperature of near-thousand degree Celsius. Despite aggressive intervention and strict monitoring, the profound inflammation caused significant damage to the ocular surface, ending up in an intractable infection with an unfavorable outcome. The heat of the molten metal at impact, the heat-retaining capacity of the heavy metal, the total area of the ocular surface exposed to the molten metal, and the duration of exposure determined the severity of the injury. The unfavorable outcome, despite an intensive treatment, in terms of visual acuity and cosmetic appearance, should be explicitly explained to the patient, and a psychiatrist consultation should be considered if necessary.

Molten metal-related ocular thermal burn: report on two cases / Queimadura térmica ocular por metal derretido: relato de dois casos

ABSTRACT We report two cases of severe thermal burns on the ocular surface and its adnexal appendages that developed secondary to exposure to molten heavy metal with a melting temperature of near-thousand degree Celsius. Despite aggressive intervention and strict monitoring, the profound inflammation caused significant damage to the ocular surface, ending up in an intractable infection with an unfavorable outcome. The heat of the molten metal at impact, the heat-retaining capacity of the heavy metal, the total area of the ocular surface exposed to the molten metal, and the duration of exposure determined the severity of the injury. The unfavorable outcome, despite an intensive treatment, in terms of visual acuity and cosmetic appearance, should be explicitly explained to the patient, and a psychiatrist consultation should be considered if necessary.

RESUMO Relatamos dois casos de queimaduras graves da superfície ocular e seus anexos causadas por exposição à metais pesados derretidos com temperatura de fusão de quase mil graus Celsius. Embora rigorosamente acompanhados, a inflamação intensa causou danos significativos para a superfície ocular, que acabou em uma infecção intratável com um resultado desfavorável. O calor do metal fundido no momento do impacto, a capacidade de retenção de calor do metal pesado, a área total da superfície ocular exposta ao metal fundido e a duração da exposição determinaram a gravidade da lesão que vai ocorrer. O resultado desfavorável, apesar do tratamento intensivo, em relação à acuidade visual e à aparência estética, devem ser claramente explicados ao paciente e uma consulta ao psiquiatra deve ser considerada, se necessário.

Tear Osmolarity and Tear Function Changes in Patients with Acromegaly.

PURPOSE: Since acromegaly is a disease with various systemic complications, it may also have ophthalmologic consequences. The aim of the current study was to compare the tear osmolarity and tear function changes in patients with acromegaly with those in healthy controls. DESIGN: Prospective, cross-sectional study. MATERIALS AND METHODS: Fifty-nine consecutive patients with acromegaly and 62 age and gender matched healthy volunteers were enrolled in the study. Tear osmolarity measurement with TearLab Osmolarity System (Tearlab, San Diego, CA), tear film break-up time (TBUT) assessment, and the Schirmer test without anesthesia were performed in the same order in each group. Growth hormone (GH) and insulin like growth factor-1 (IGF1) levels were also determined in the study group. RESULTS: The mean TBUT was lower in acromegalic patients (9.1 ± 3.6 seconds) than in healthy controls (10.7 ± 2.9 s) (p = 0.009). The difference between the two groups in tear osmolarity and Schirmer test results (p = 0.08 and p = 0.9, respectively) was not statistically different. CONCLUSIONS: Acromegaly may a cause a decrease in TBUT in the affected patient. Preservation of normal tear osmolarity and normal Schirmer test results suggests that this might be due to effects on the meibomian glands.

Impression Cytology in Different Types of Contact Lens Users.

This study compared tear function tests and cytologic changes on the conjunctival surface in asymptomatic patients wearing contact lens of different materials. Included in this study were 40 eyes wearing daily wear 4 week replacement hydrogel (H) lenses, 32 eyes wearing silicone hydrogel (SiH) lenses, 18 eyes wearing rigid gas-permeable (RGP) lenses, and 21 healthy eyes (no lenses) as the control group. Epithelial morphology of the conjunctival surface was evaluated, based on Nelson classification with conjunctival impression cytology (CIC), after the tear break-up time (TBUT) and Schirmer test were performed. The mean values of the Schirmer and TBUT tests were significantly higher in the control group than in the other lens groups (p < 0.001). Grade 0 was the most frequent CIC in the control group (66.7%) and least frequent in the SiH lens group (40.6%); grade I was least frequent in the control and RGP groups (33.3%) and most frequent in the SiH lens group (40.6%). Moreover, grade 2 was most frequent in the SiH lens group (18.8%). There was no statistically significant difference in goblet cell densities between the groups (p = 0.462). In addition to the different Schirmer and TBUT test results between contact lens wearers and healthy non-wearers, some cytologic changes may occur on the ocular surface with direct mechanical effects of contact lenses. This simple and noninvasive technique may be used to evaluate the ocular surface with regard to intolerance to contact lenses.

Corneal decompensation after selective laser trabeculoplasty.

A 64-year-old Caucasian man referred for decreased vision after selective laser trabeculoplasty (SLT). Slit lamp examination revealed diffuse corneal edema. Despite intensive topical treatment including steroids, corneal edema did not resolve; on the contrary, it advanced to bullous keratopathy. Corneal edema after SLT is an exceptionally rare complication and in all of the previous reports edema resolved with medical treatment. To the best of our knowledge, this is the first report presenting persistent corneal edema after SLT.

Prevalence and antimicrobial susceptibilities of anaerobic bacteria isolated from perforated corneal ulcers by culture and multiplex PCR: an evaluation in cases with keratitis and endophthalmitis.

BACKGROUND: Anaerobic bacteria play an important role in eye infections; however, there is limited epidemiologic data based on the the role of these bacteria in the etiology of keratitis and endophthalmitis. The aim of this re- search is to determine the prevalence of anaerobic bacteria in perforated corneal ulcers of patients with keratitis and endophthalmitis and to evaluate their antimicrobial susceptibilities. METHODS: Corneal scrapings were taken by the ophthalmologist using sterile needles. For the isolation of anaerobic bacteria, samples were inoculated on specific media and were incubated under anaerobic conditions obtained with Anaero-Gen (Oxoid & Mitsubishi Gas Company) in anaerobic jars (Oxoid USA, Inc. Columbia, MD, USA). The molecular identification of anaerobic bacteria was performed by multiplex PCR and the susceptibilities of an- aerobic bacteria to penicillin, chloramphenicol, and clindamycin were determined with the E test (bioMerieux). RESULTS: 51 strains of anaerobic bacteria belonging to four different genuses were detected by multiplex PCR and only 46 strains were isolated by culture. All of them were found susceptible to chloramphenicol whereas penicillin resistance was found in 13.3% of P.anaerobius strains, clindamycin resistance was found in 34.8% of P.acnes and 13.3% of P. anaerobius strains. Additionnaly, one strain of P. granulosum was found resistant to clindamycin, one strain of B. fragilis and one strain of P.melaninogenica were found resistant to penicillin and clindamycin. CONCLUSIONS: Routine analyses of anaerobes in perforated corneal ulcers is inevitable and usage of appropriate molecular methods, for the detection of bacteria responsible from severe infections which might not be deter- mined by cultivation, may serve for the early decision of the appropriate treatment. Taking into account the in- creasing antimicrobial resistance of anaerobic bacteria, alternative eye specific antibiotics effective against anaer- obes are needed to achieve a successful treatment.

Comparison of the effects of first and second generation silicone hydrogel contact lens wear on tear film osmolarity.

AIM: To compare the effects of first and second generation silicone hydrogel (SiH) contact lens wear on tear film osmolarity. METHODS: The healthy subjects who have never used contact lenses before were enrolled in the study. Tear film osmolarity values of 16 eyes (group 1) who wore first generation SiH contact lenses were compared with those of 18 eyes (group 2) who wore second generation SiH contact lenses after three months follow-up. RESULTS: Before contact lens wear, tear film osmolarity of groups 1 and 2 were 305.02±49.08 milliosmole (mOsm) and 284.66±30.18mOsm, respectively. After three months of contact lens wear, osmolarity values were found 317.74±60.23mOsm in group 1 and 298.40±37.77mOsm in group 2. Although osmolarity values for both groups of SiH contact lens wear after three months periods were slightly higher than before the contact lens wear, the difference was not statistically significant. CONCLUSION: Contact lens wear may cause evaporation from the tear film and can increase tear film osmolarity leading to symptoms of dry eye disease. In the current study, there is a tendency to increase tear film osmolarity for both groups of SiH contact lens wear, but the difference is not statistically significant.

Richner-Hanhart syndrome (tyrosinemia type II): a case report of delayed diagnosis with pseudodendritic corneal lesion.

Richner-Hanhart syndrome (tyrosinemia type II) is a rare autosomal recessive disease associated with high serum tyrosine levels caused by the deficiency of tyrosine aminotransferase enzyme. We report a 15-year-old female patient with complaints of bilateral photophobia and tearing, which started during the infancy period. Biomicroscopic examination revealed bilateral circular corneal opacities on the inferior quadrant and small dendritic lesions at the center of the circular opacities. Blood tests showed a tyrosine level of 508 micromol/L (normal range: 30-150). On her dermatologic examination, plantar hyperkeratosis and seborrheic dermatitis were noted, and mild mental retardation was detected. One and a half months after the tyrosine- and phenylalanine-restricted diet, her tyrosine level dropped to 395 micromol/L level, her corneal lesions subsided, and a symptomatic relief was achieved. Tyrosinemia type II should be suspected in patients demonstrating dermatologic signs, especially palmoplantar keratosis, associated with bilateral pseudodendritic corneal lesions unresponsive to antiviral therapy.

Traumatic corneal flap dehiscence 6 years after LASIK.

PURPOSE: To report a case of LASIK flap dehiscence caused by blunt trauma 6 years after uneventful refractive surgery. METHODS: A 32-year-old man presented 3 hours after being struck by a carton edge in his left cornea, causing dehiscence of the LASIK flap. RESULTS: At initial examination, uncorrected visual acuity (UCVA) was 20/200 in the left eye. Minimal flap dehiscence was seen on the inferior corneal quadrant. A therapeutic bandage soft contact lens was placed and topical medical therapy was administered. Ten days after trauma, UCVA was 20/50 and best spectacle-corrected visual acuity was 20/30 in the left eye. At 7-month follow-up, the patient's clinical status did not change. CONCLUSIONS: Blunt corneal trauma occurring several years after uneventful LASIK may cause corneal flap dehiscence. Appropriate and prompt treatment usually is successful.

Tear film osmolarity in patients with thyroid ophthalmopathy.

PURPOSE: To compare tear film osmolarity between patients with thyroid ophthalmopathy and normal healthy subjects. METHODS: The tear film osmolarity in 15 normal subjects (15 eyes) (control group) and 21 patients (21 eyes) with thyroid ophthalmopathy was evaluated. Tear film osmolarity in milliosmole (mOsm) was determined by using an auto-osmometer. The palpebral fissure width, degree of proptosis, and tear break-up time (BUT) were also determined. The results for the two groups were compared statistically. RESULTS: The mean palpebral fissure width was 9.13 +/- 0.74 mm in the healthy subjects and 13.33 +/- 1.55 mm in the thyroid ophthalmopathy patients. This difference was statistically significant (P = 0.0001). The mean proptosis was 15.33 +/- 1.39 Hertel units in the healthy subjects and 20.71 +/- 0.95 Hertel units in the patients. This difference was also statistically significant (P = 0.0001). The mean tear BUT was 6.35 +/- 1.56 s in the patients and 18.27 +/- 1.53 s in the healthy subjects, and this difference was also statistically significant (P = 0.0005). The mean tear film osmolarity was 290.80 +/- 13.58 mOsm in the healthy subjects and 340.38 +/- 18.74 mOsm in the patients. There was a statistically significant difference between the groups (P = 0.0001). CONCLUSIONS: The significantly higher tear film osmolarity in patients with thyroid ophthalmopathy was most likely due to the increased proptosis and lid fissure width. These conditions may lead to injury of the ocular surface.

Lymphocyte subgroups and natural killer cell activity in recurrent herpetic stromal keratitis.

PURPOSE: Although the role of natural killer cells in the defense against certain viral infections has been published, little is known about the role of lymphocyte subgroups in recurrent herpetic stromal keratitis. Accordingly, serum levels of major immunoglobulins (IgG, IgA, and IgM) and IgG subgroups, the lymphocyte subgroups, and natural killer cell activity were investigated in patients with recurrent herpetic stromal keratitis. METHODS: Eleven patients with recurrent herpetic stromal keratitis and 10 healthy subjects were included. A delayed-type hypersensitivity skin test was performed in addition to the determination of serum immunoglobulin levels, IgG subgroups, peripheral blood lymphocyte percentages, and natural killer cell activity in both groups. RESULTS: The result of the delayed-type hypersensitivity skin test was positive in all patients with recurrent herpetic stromal keratitis and healthy subjects. No significant difference was obtained in serum immunoglobulin levels and IgG subgroups between the patients and healthy subjects. Among the cell surface antigens (CD3, CD4, CD8, CD16, CD19, and CD20), only CD8+ (i.e., cytotoxic) T-lymphocyte percentages were significantly increased (P=0.003), and the CD4:CD8 ratio was significantly decreased in the patients compared to the healthy subjects (P=0.021). There was no significant difference in the expression of CD16+ natural killer cells between both groups, despite a significantly lower natural killer cell activity in patients with recurrent herpetic stromal keratitis (P=0.011). CONCLUSIONS: These results indicate that human cytotoxic T cells show a difference in numbers and natural killer cell activity that may affect the prognosis of recurrent herpetic stromal keratitis.

Comparison of corneal thickness of long-term contact lens wearers for different types of contact lenses.

PURPOSE: To compare the central corneal thickness (CCT) values of long-term wearers of different types of contact lenses with those of each other and a normal control group. METHODS: Twenty-three healthy eyes with no history of contact lens wear were used for the control group. Forty-eight eyes were evaluated in four different groups according to the type of contact lens worn; each group comprised 12 eyes. Group 1 (SofLens 38) and group 2 (Contact Day 30) had worn daily-wear frequent-replacement soft contact lenses with a 38% and 55% water content, respectively, and they had worn their lenses for an average of 4.28 +/- 1.70 years and 3.71 +/- 1.11 years, respectively. Group 3 (Wöhlk A90) and group 4 (Conflex-air) had worn daily-wear rigid gas-permeable (RGP) contact lenses with a Dk/t value of 68 and 22, respectively, and they had worn their lenses for an average of 3.00 +/- 0.63 years and 3.25 +/- 1.17 years, respectively. CCT values in micrometers were measured by optical coherence tomography. RESULTS: When comparing the CCT between the control group and the contact lens groups, the CCT was significantly thinner in the group wearing Conflex-air RGP contact lenses with a low Dk/t value (P = 0.010). In comparing the CCT among the four contact lens groups, the CCT was significantly thinner in the group wearing SofLens 38 contact lenses with a water content of 38% than in the group wearing Contact Day 30 contact lenses with a water content of 55% (P = 0.004). There was also significant thinning in the group wearing Conflex-air RGP contact lenses versus the group wearing Contact Day 30 soft contact lenses (P = 0.0005). CONCLUSIONS: CCT was significantly thinner in patients wearing long-term low-Dk/t RGP contact lenses compared to no contact lens wear and soft contact lenses with a water content of 55%. CCT was also decreased significantly in long-term soft contact lens wear with a water content of 38% compared to 55%.