Age-Related Changes in Corneal Epithelial Thickness Measured with an Ultrasound Pachymeter.

Background: There is increasing research on the aging process of the cornea and its effect on the corneal parameters measured objectively. Nevertheless, the association of corneal epithelial thickness (CET) with age has yet to be fully illustrated. Purpose: We aimed to measure CET in healthy subjects to determine its age-related variation by using an ultrasound device. Patients and Methods: A total of one hundred and three subjects were enrolled in this study and grouped according to age: Group < 30 years, 31-40 years, 41-50 years, 51-60 years, 61-70 years, and > 71 years. The CET and total central corneal thickness (CCT) of each subject were measured by the Sonogage Corneo-Gage Plus 2 (Cleveland, Ohio) ultrasound pachymeter. The relationships between thickness values, laterality, age groups, and gender were analyzed using the Jonckheere-Terpstra test. The Partial correlation test was employed to assess the effect of age on the CET and CCT. Results: The mean CET was 47.88±1.15µm, with no statistically significant gender-related difference between right and left eyes. In addition, the CCT difference detected between female and male eyes was insignificant. The difference in mean CET across age groups was statistically significant (p =0.029). The difference in mean CET of left eyes across age groups was statistically significant (p=0.031). The mean CET and left CET of the oldest group were significantly thinner than the younger groups. Conclusion: Ultrasound pachymeter of the corneal epithelium demonstrated that there was no correlation between age and CCT, or gender. The CET becomes thinner with age in the central zone in both genders and there is no difference between males and females. Based on these results, age has a negative effect on CET. These findings could offer further insight into age-related changes in the cornea.

Correlation between corneal thickness, keratometry, age, and differential pressure difference in healthy eyes.

To determine the use of differential pressure difference (DPD), in air-puff differential tonometry, as a potential biomechanical measure of the cornea and elucidate its relationship with the intraocular pressure (IOP), central corneal thickness, corneal curvature, and age. This study comprised 396 eyes from 198 patients and was conducted at Acibadem University, School of Medicine, Department of Ophthalmology, Istanbul, Turkey. The central corneal curvature and refraction of the eyes were measured using an Auto Kerato-Refractometer (KR-1; Topcon Corporation, Tokyo, Japan). IOP and central corneal thickness were measured using a tono-pachymeter (CT-1P; Topcon Corporation, Tokyo, Japan), wherein two separate readings of IOP were obtained using two different modes: 1-30 and 1-60. The difference between these two readings was recorded as the DPD. The factors affecting the DPD were determined by stepwise multiple linear regression analysis. DPD varied over a dynamic range of - 3.0 to + 5.0 mmHg and was weakly correlated with the central corneal thickness (r = 0.115, p < 0.05). DPD showed no significant correlation with IOP 1-30 (p > 0.05). A weak but statistically significant (p < 0.05) positive correlation of DPD was observed with age (r = 0.123), Kavg (r = 0.102), and the CCT (r = 0.115). There was a significant correlation between DPD and Kavg, CCT, and age. There was no significant correlation between DPD and IOP 1-30. Age-related changes in the corneal ultrastructure may be a plausible explanation for the weak positive association between age and DPD. The proposed method may prove a valid non-invasive tool for the evaluation of corneal biomechanics and introduce DPD in the decision-making of routine clinical practice.

Intrauterine Cataract Diagnosis and Follow-up

In this article, we report a 21-gestational-week fetus diagnosed with congenital cataract by ultrasonography. The parents decided to terminate the pregnancy and asked for examination of the fetus. An amniocentesis was performed for fetal karyotyping. After termination of the pregnancy, fetal autopsy was conducted. Whole exome sequencing (Trio-WES) analysis of the mother and father was done from peripheral blood samples. In the pathologic autopsy report, bilateral anterior and posterior subcapsular cataracts were confirmed. Whole exome sequencing analysis revealed a previously unreported class 3 variant of uncertain significance (c755A>G [P.Lys252Arg]) of the CRYBB1 gene, which is associated with congenital cataract, that was homozygous in the fetus and heterozygous in the parents. The obtained result is consistent with a genetic diagnosis of isolated autosomal recessive cataract.

The effect of hemodialysis on intraocular pressure.

BACKGROUND: The effect of hemodialysis (HD) on intraocular pressure (IOP) has been investigated before, but there is a lack of consensus. Clinicians dealing with renal failure patients are interested in the potential negative effects of HD on IOP and the course of glaucoma. OBJECTIVES: The aim of this study was to investigate the effects of HD on IOP in patients with end-stage renal disease. MATERIAL AND METHODS: This prospective study included 106 patients who were receiving outpatient hemodialysis. Patient history of systemic and ophthalmologic conditions was recorded. Serum osmolality (mOsm), blood urea nitrogen (BUN), blood glucose (BG), bicarbonate (BC), and hematocrit (Hct) levels at the start of HD (pre-HD), at the end of HD (end-HD), and 30 min after HD (post-HD) were measured. Systolic and diastolic blood pressures (SBP and DBP) and IOP were measured at pre-HD, 1-hour intervals during HD, end-HD, and post-HD. RESULTS: A significant decrease in mOsm and BUN and a significant increase in BG, BC, and Hct levels were observed at end-HD (p < 0.05). Mean IOP was 16.71 ±2.51 mm Hg at pre-HD, 15.52 ±3.18 mm Hg at endHD, and 15.23 ±2.73 mm Hg at post-HD (p = 0.001; F = 4.439). Post-HD SBP and DBP were significantly lower than at pre-HD (p < 0.001). There was a positive correlation between the change in IOP and the change in mOsm and the change in BUN at end-HD (r = 0.315, p = 0.004; and r = 0.279, p = 0.012, respectively). CONCLUSIONS: IOP decreased significantly during HD in this study. Additional research on the effects of the change in blood parameters and ocular perfusion pressure on IOP and optic nerve perfusion during HD is recommended.

Estrogen- and Progesterone-Induced Variation in Corneal Parameters According to Hormonal Status.

OBJECTIVES: To determine the effects of estrogen and progesterone on corneal thickness, curvature, and biomechanics in healthy corneas according to hormonal status. METHODS: The study included four groups of females: group A (menstruating, not pregnant, not lactating, and not menopausal; n=100), group B (pregnant; n=50), group C (lactating; n=50), and group D (menopausal; n=50). Group A was subdivided according to age, as subgroup A15-25 (age 15-25 years) and subgroup A>25 (age >25 years). Blood estradiol and progesterone levels were measured in each participant. All the participants underwent a full ophthalmologic examination, including corneal thickness and corneal topography measurement, and evaluation of corneal biomechanical properties. RESULTS: The corneal resistance factor and anterior corneal flat keratometry values were significantly higher in group D (P=0.040 and P=0.026, respectively) than in the other three groups. Posterior corneal steep keratometry values were significantly higher in subgroup A>25 during the preovulatory phase than ovulatory and postovulatory phases (P=0.012). In group B, there was a significant negative correlation between gestational week and intraocular pressure (IOP) (r=-0.322, P=0.024). Corneal volume was significantly higher during the early postpartum period than the late postpartum period in group C (P=0.028). Intraocular pressure, Goldman-correlated IOP, and corneal-compensated IOP differed significantly between the groups (P<0.05). CONCLUSIONS: Blood levels of estrogen and progesterone were associated with variations in IOP, but estrogen and progesterone did not have a consistent effect on topographic parameters or biomechanical properties in healthy corneas.

A sample predictive model for intraocular pressure following laser in situ keratomileusis for myopia and an "intraocular pressure constant".

PURPOSE: To describe a sample predictive model for intraocular pressure (IOP) following laser in situ keratomileusis (LASIK) for myopia and an IOP constant. METHODS: The records of patients that underwent LASIK for myopia and myopic astigmatism via WaveLight Allegretto Wave Eye-Q 400 Hz excimer laser and Hansatome XP microkeratome were retrospectively reviewed. Patients with no systemic or ocular disease other than myopia or myopic astigmatism were included in the study. Preoperative and postoperative month 1 data and intraoperative data were used to build the predictive model for IOP after LASIK. The IOP constant was calculated by subtracting the predicted IOP from preoperative IOP. The paired samples t test, Pearson's correlation analysis, curve estimation analysis, and linear regression analysis were used to evaluate the study data. RESULTS: The study included 425 eyes in 214 patients with a mean age of 32 ± 7.8 years. Mean spherical equivalent of the attempted correction (SE-ac) was -3.7 ± 1.7 diopters. Mean post-LASIK decrease in IOP was 4.6 ± 2.3 mmHg. The difference between preoperative and postoperative IOP was statistically significant (P < 0.001). SE-ac, preoperative IOP, and central corneal thickness had highly significant effects on postoperative IOP, based on linear regression analysis (P < 0.001 and R 2 = 0.043, P < 0.001 and R 2 = 0.370, and P < 0.001 and R 2 = 0.132, respectively). Regression model was created (F = 127.733, P < 0.001), and the adjusted R 2 value was 0.548. CONCLUSIONS: Evaluation of IOP after LASIK is important in myopic patients. The present study described a practical formula for predicting the true IOP with the aid of an IOP constant value in myopic eyes following LASIK.

The Effect of Smoking on Corneal Biomechanics.

PURPOSE: To determine the effect of smoking on corneal biomechanical behavior. MATERIALS AND METHODS: The medical records of consecutive patients that presented to the ophthalmology department were reviewed. History of smoking and ophthalmological examination findings were recorded. The smoking group met the following criteria: a clear history of and present smoking habit, negative history of corneal disease and surgery, ocular response analyzer measurement at the time of examination, and a waveform score ≥3.7. Nonsmokers (never smoked or quit smoking ≥6 months earlier) that met the same criteria constituted the control group. Corneal biomechanical parameters were measured using ocular response analyzer. Data were analyzed using Pearson's χ2 test, Mann-Whitney U test, and Spearman's correlation coefficient. RESULTS: The smoking group included 166 eyes of 166 patients with a mean age of 38.7 ± 11.95 years, and the control group consisted of 170 eyes of 170 patients with a mean age of 38.40 ± 12.2 years. Mean cumulative smoking dose in the smoking group was 9.59 ± 11.87 pack-years (0.04- 75.00). There was no significant correlation between cumulative smoking dose and corneal hysteresis and corneal resistance factor (P = 0.382 and 0.074, respectively). There were no significant differences in corneal hysteresis or the corneal resistance factor between the two groups (P > 0.05). There was no significant difference in corneal hysteresis between those in the smoking group aged 18-44 years and those aged 45-64 years (P = 0.258), whereas in the control group mean corneal hysteresis was significantly lower in the 45-64 year olds than in the 18-44 year olds (P = 0.034). CONCLUSIONS: Although there was no significant difference in corneal biomechanics between smoking and control groups, the decrease in corneal hysteresis with aging was less apparent in the smoking group, which may be due to the potential changes in the cornea's microstructure induced by smoking during aging and the effect of smoking in aged corneal tissue viscosity.

Corneal Biomechanical Properties in Aspirin Users.

PURPOSE: To analyze corneal biomechanical properties in aspirin users using an ocular response analyzer. METHODS: This study included 80 eyes of 40 aspirin users and 80 eyes of 40 individuals who did not use aspirin. Corneal hysteresis (CH), the corneal resistance factor (CRF), Goldman-correlated intraocular pressure (IOPg), and corneal compensated intraocular pressure (IOPcc) were measured in all participants. The independent samples t test was used to compare measurements in the aspirin users and nonusers in the total study population, and in the diabetic patient subgroup. Pearson's correlation analysis was used to examine the relationship between the measured variables in the aspirin users and nonusers. RESULTS: Aspirin users (59.08 ± 11.83 years) were older than nonusers (39.82 ± 12.97 years; p < 0.001). The mean CH was significantly lower in the aspirin user group than in the nonuser group (p = 0.013). Mean IOPg and mean IOPcc were also significantly higher in the aspirin user group (p = 0.027 and p = 0.002, respectively). The mean CRF was lower in the aspirin user group, but not significantly (p = 0.70). There was a positive correlation between CH and CRF (r = 0.767, p < 0.001), and between CRF and IOPg (r = 0.680, p < 0.001), and a negative correlation between CH and IOPcc (r = -0.415, p < 0.001). CONCLUSIONS: Aspirin should be taken into account when interpreting the results of corneal biomechanical measurements.

Retinal tear: an unusual complication of ocular toxoplasmosis.

PURPOSE: It is aimed to report on a 16-year-old patient with acquired ocular toxoplasmosis complicated by a retinal tear. METHODS: Retrospective medical chart review. RESULTS: A 16-year-old Caucasian female presented with vision loss in her right eye. In addition to a white active lesion between the fovea and the optic nerve head, marked vitreous opacification was noted. She was diagnosed with ocular toxoplasmosis. The patient was treated with oral azithromycin, clindamycin, and trimethoprimsulfamethoxazole. One month later, retinochoroiditis resolved and vitreous cleared. Three months after onset, patient presented with floaters in the right eye and a retinal tear was located at the temporal region of the retina. Prophylactic argon laser treatment that encircled the retinal tear was performed. No other abnormalities were noted during 6 months of follow-up. CONCLUSIONS: Retinal tear associated with ocular toxoplasmosis is rare; however, a retinal tear can occur due to vitreoretinal traction following post-inflammatory structural alteration of the vitreous. Retinal tears may be seen during the healing phase, when the inflammation turns into tightening of vitreous substance. Careful retinal examination in cases of ocular toxoplasmosis is warranted, especially in patients with severe vitreous inflammation.

Supracor hyperopia and presbyopia correction: 6-month results.

PURPOSE: To investigate refractive and visual outcomes and complications of the Supracor procedure to treat presbyopia. METHODS: A total of 123 eyes from 68 presbyopic patients with hyperopia were enrolled in this prospective, nonrandomized, clinical trial. The Supracor procedure was performed using the Technolas excimer laser 217P (Technolas Perfect Vision GmbH). Follow-up eye examinations were performed at postoperative day 1, month 1, and month 6. RESULTS: All 123 surgeries were uneventful. At 6 months postoperatively, uncorrected distance visual acuity was 20/20 or better in 27 (22.0%) eyes and 20/25 or better in 45 (36.6%) eyes. At 6 months postoperatively, 35 (28.5%) eyes lost 1 line and 13 (10.6%) eyes lost 2 lines of corrected distance visual acuity (CDVA). At 6 months postoperatively, uncorrected near visual acuity was 20/20 or better in 95 (77.2%) eyes and 20/25 or better in 110 (89.4%) eyes. At 6 months postoperatively, 6 (4.9%) eyes lost 1 line of corrected near visual acuity. CONCLUSIONS: The Supracor presbyopia procedure showed good near visual acuity outcomes over 6 months follow-up but loss of CDVA occurred in 39.1% of eyes.

Comparison of visual acuity, refractive results and complications of femtosecond laser with mechanical microkeratome in LASIK.

AIM: To compare the outcomes of laser in situ keratomileusis (LASIK) performed with a femtosecond laser (Femtec, Technolas Perfect Vision GmbH, Germany) versus a mechanical microkeratome (Hansatome, Bausch and Lomb, USA) for the correction of myopia and astigmatism. METHODS: In this retrospective study, patients who had undergone LASIK using the 80-kHz Femtec femtosecond laser were compared to age- and refraction-matched patients in whom the Hansatome microkeratome was used. Refractive and visual results 1 month and 3 months postoperatively, and complication rates were compared between the two groups. RESULTS: A total of 280 eyes were analyzed (140 in each group). At 3 months postoperatively in the Femtec vs Hansatome group, spherical equivalent refraction was within ±1.00D of emmetropia in 140 vs 138 eyes (P=0.498), the cylinder was within ±0.50D in 137 vs 139 eyes (P=0.622), and the UDVA was 20/20 or better in 136 vs 137 eyes (P=0.724), respectively. There was no statistically significant difference in the complication rates between the two groups (P=0.099). CONCLUSION: LASIK performed both with Femtec femtosecond laser and Hansatome microkeratome achieved satisfactory refractive and visual results at 3 months postoperatively, without significant differences in efficacy, safety, and complication rates between the two procedures.

Late onset of deep corneal vascularization: a rare complication of intrastromal corneal ring segments for keratoconus.

PURPOSE: To report deep corneal vascularization noted 3 years after intrastromal corneal ringsegments (Intacs) implantation for the treatment of keratoconus. METHODS: A 33-year-old male keratoconus patient intolerant to rigid gas permeable contact lens in the right eye underwent Intacs implantation. At 2 years postoperatively, slit-lamp examination of the right eye revealed superficial corneal vascularization inferotemporally, extending 1.5 mm from the limbus. At 3 years postoperatively, the slit-lamp examination of the right eye revealed deep stromal vascularization extending to and arborizing along the temporal segment. Also, superficial vascularization was noted along the nasal segment inferiorly. The Intacs segments were then explanted. RESULTS: On post-explantation day 10, the deep vessels regressed to ghost vessels with topica corticosteroid therapy. CONCLUSIONS: The authors present a rare case where deep corneal vascularization was noticed 3 years following Intacs implantation for keratoconus. All patients having superficial vascularization away from the incision site need to be followed for this rare complication.