Compensatory Corneal Epithelial Changes After Femtolaser - Assisted Intracorneal Rings Implantation in Early and Moderate Cases of Keratoconus.

Purpose: To study the compensatory corneal epithelial changes after femtolaser-assisted intracorneal ring segment (ICRS) implantation in early and moderate cases of keratoconus (KC) using anterior segment optical coherence tomography (AS-OCT). Patients and Methods: A prospective observational non-randomized study of 40 eyes with mild to moderate KC received femtolaser-assisted ICRS implantation. Ferrara ICRS with different arc lengths and thicknesses were used according to the patients' tomographic pattern. Patients had a clear central cornea, keratometry reading < 60 diopters, and corneal thickness > 400 microns. AS-OCT was performed preoperatively and at 1, 3, and 6 months after surgery. Corneal epithelial thickness (CET) was measured over 17 points (2 mm central and 16 points on 2-5 mm and 5-7 mm annular zones) over the pupil center. All data were collected and analyzed. Results: Comparing the preoperative and postoperative data, there was a statistically significant increase in the CET postoperatively throughout the 6-month follow-up period in all zones (p<0.001). The epithelial thickness (ET) was noticed shortly around and central to the ring ridges by the first month (5-7 mm zone). By the third month, the flattened central cornea (2 mm zone) and the 2-5 mm zone showed a significant increase in ET up to the 6th month. Conclusion: ICRS implantation in KC results in a thicker and more regular epithelium in the central corneal zone as a secondary response to the corneal stromal changes induced by the implants.

Comparison Between the Effect of Femtosecond Laser in situ Keratomileusis (FS-LASIK) and Femtosecond Small Incision Lenticule Extraction (FS-SMILE) on the Corneal Endothelium.

PURPOSE: To compare the effect of FS-LASIK and FS-SMILE on the corneal endothelial cell density (ECD) and morphology. PATIENTS AND METHODS: This is a prospective, cohort observational study that included 80 eyes of two equal groups of patients. Forty eyes were subjected to the FS-LASIK, and 40 eyes were subjected to the FS-SMILE. In both groups, patients, age ranged between 19 and 37 years with myopia ranges from -0.75 to -9.00 diopters (D) and astigmatism up to -3.00D. The ECD, coefficient of variation (CV), and hexagonality (HEX) in both groups were compared over six months. Specular microscopy was used to evaluate the corneal endothelium throughout the study. RESULTS: In both groups, ECD showed a statistically significant decrease while CV showed a statistically significant increase in the first month postoperatively. The FS-SMILE had more impact on both ECD and CV until the third and six months, respectively. Hexagonality showed a significant decrease in both groups throughout the whole study. In both groups, no vision-threatening complications occurred, and no eyes developed any corneal complications over a six-month follow-up period. CONCLUSION: Although the ECD, CV, HEX are statistically affected in both FS-LASIK and FS-SMILE groups, both procedures have no significant adverse effects on the ECD and morphology. The impact of the FS-SMILE group may be due to the deeper penetration of the femto laser in the corneal tissue compared to the FS-LASIK. The closer the femto laser to the endothelium, the more exposure to the shock waves and heat energy, although minimal but it can cause collateral damage to this layer. The effects of FS-SMILE surgery on corneal endothelial cells and morphology need further investigations.

Three-Year Effect of Phakic Intraocular Lenses on the Corneal Endothelial Cell Density.

PURPOSE: To compare the effect of three different phakic intraocular lenses (pIOLs) on the corneal endothelial cell density (ECD). PATIENTS AND METHODS: This was a prospective observational cohort study that included 60 eyes (30 patients) with axial myopia of -6.50 to -22.00 diopters (D). The Verisyse anterior chamber (AC) rigid iris fixated pIOL, the Veriflex (AC) flexible iris fixated pIOL, and the Visian posterior chamber (PC) implantable collamer lens (ICL) were implanted in three equal groups of patients. The effect of the three pIOLs on the ECD was compared over a follow-up period of one week, and one, three, and six months, and one, two, and three years. Specular microscopy was done to evaluate the cornea before the surgery and throughout the study. Changes were statistically analyzed and compared. RESULTS: In the first three postoperative months, Verisyse and Veriflex pIOLs induced almost the same amount of endothelial cells loss of 10.3% and 10.6%, respectively, while ICLs showed endothelial cells loss of 3.5%. At the end of the three-year study, Veriflex pIOLs induced the highest rate of endothelial cell loss of 25%, while Verisyse and ICL lenses showed endothelial cells loss of 15.7% and 13.4%, respectively. The main effect of time and type of lens was statistically significant (p<0.001). CONCLUSION: All pIOLs cause a decrease in ECD. The AC pIOLs tend to be associated with more cell loss than PC pIOLs. Surgical insult is the important factor responsible for the early endothelial cell loss, while the material from which the pIOL is made may be an important factor for the continuous corneal endothelial cell loss over a long time.

The effect of oral contraceptive pills on the macula, the retinal nerve fiber layer, the ganglion cell layer and the choroidal thickness.

BACKGROUN: To evaluate the effect of oral contraceptive pills (OCP) on the macula, the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), and the choroidal thickness (CT). METHODS: In this prospective observational cross-sectional study, 60 eyes of 30 healthy women taking monophasic OCP (0.03 mg ethinylestradiol and 0.15 mg levonorgestrel) for contraception for at least 1 year were compared with 60 eyes of a control group of 30 healthy women who were not taking any OCP. Spectral-Domain Optical Coherence Tomography (SD-OCT) was used to evaluate the macula, the RNFL, the GCL, and the CT. Measurements were taken in the follicular phase (day 3) of the last menstrual cycle in all women. The body mass index (BMI) scores of all participants were also recorded. RESULTS: No disparity in terms of age and BMI between both groups was observed (p = 0.444, p = 0.074, respectively). All the macular parameters measurements were considerably lower in the OCP group compared to the control group (p < 0.001). Also, the RNFL thickness, the GCL thickness, and the CT were all significantly thinner in the OCP group (p < 0.001). CONCLUSIONS: The use of OCP can cause significant changes in the retina and choroid thickness over 1 year period. The women who are using OCP for a longer duration could have some eye problems. OCT should be routinely done for follow up. Further long term studies are required, using different preparations of OCP. It is important to find out when this thickness alterations can be clinically significant or symptomatic and if these changes are reversible or not.

Tear meniscus evaluation after microkeratome laser in situ keratomileusis, femtosecond laser and femtosmile laser techniques using anterior segment optical coherence tomography.

PURPOSE: The purpose of this study was to compare the effects of three different corneal refractive surgeries: microkeratome laser in situ keratomileusis (LASIK), femtosecond laser in situ keratomileusis (FS-LASIK) and femtosecond small incision lenticule extraction (FS-SMILE) on 6-month postoperative stability of tear film to provide a basis for selection of operative procedures. PATIENTS AND METHODS: This is a prospective, randomized, comparative study that included 90 eyes of three equal groups of patients. Each group was subjected to a different laser technique: LASIK, FS-LASIK and FS-SMILE. Using anterior segment spectral domain optical coherence tomography (AS-SD-OCT), the lower tear meniscus parameters were measured preoperatively and 1 week, 1 month, 3 months and 6 months postoperatively. Changes were studied and compared. RESULTS: There was a statistically significant difference in tear meniscus height (TMH) between FS-SMILE and FS-LASIK in the first week (P = 0.003) and first month (P = 0.002) with no statistically significant difference between both techniques at 3 and 6 months postoperatively. In FS-SMILE, TMH returned to 95% of its preoperative level after 1 month. There was no statistically significant difference in TMH between FS-LASIK and microkeratome LASIK techniques after 1 week and 1 month, but there was a statistically significant difference between both techniques in 3 months (P = 0.019) and 6 months (P = 0.032). Tear meniscus area (TMA) showed no statistically significant difference between FS-SMILE and FS-LASIK at all points of follow-up, but there was a statistically significant difference between both techniques and microkeratome LASIK (all P < 0.05). Microkeratome LASIK parameters failed to reach the preoperative level till 6 months. CONCLUSION: Early recovery of the lower TMH can be achieved as early as 1 month post-operatively with the FS-SMILE technique compared to FS-LASIK and microkeratome LASIK techniques.

Histopathological Parameters in Pterygia and Significant Clinical Correlations.

PURPOSE: To evaluate the clinical and histopathological parameters of pterygium to determine significant correlations between parameters that can affect management strategies. METHODS: A total of 47 pterygia were clinically examined and excised for histopathological evaluation of epithelial and stromal changes. Some samples were immunostained with P53 (a protein of 53 kilodalton used as dysplastic epithelial marker), CD20 (CD/cluster of differentiation, are group of surface receptors providing targets for cellular immunophenotyping, CD20 as a B lymphocyte marker), CD 3 (as T lymphocyte marker) or vascular endothelial growth factor (VEGF/as vascular marker). RESULTS: Most patients were male (59.6%). Cosmetic complaints (83%), grade II redness (61.7%), grade 2 extension (63.8), and associated astigmatism of <2.5 D (83%) were observed. Histopathological features included solar elastosis (100%), squamous hyperplasia (83%), increased stromal vascularity with hemorrhage (76.6%), and lymphocytic stromal infiltration, perivascular distribution, and mild epithelial lymphocytic exocytosis in 72.3%, 74.5%, and 70.2% of cases, respectively. Other changes included goblet cell hyperplasia (31.9%), prominent epithelial pigmentation (48.9%), and, most importantly, epithelial atypia (53.2%). Clinical redness was significantly correlated with vascularity, epithelial hyperplasia, and lymphocytic stromal infiltration; lymphocytic stromal infiltration was also significantly correlated with pterygium extension and with low astigmatism. CONCLUSION: The inflammatory response was mild in most cases and the density was not significantly correlated with any clinical parameter. Vascularity was related to clinical redness. Treatment with anti-VEGF may be beneficial, even for grade 1 pterygia that are not dominantly fibrotic.

Age- and sex-related differences in corneal epithelial thickness measured with spectral domain anterior segment optical coherence tomography among Egyptians.

Is to measure the corneal epithelial thickness (CET) in a group of healthy Egyptian population and to investigate its variation with age and sex using spectral domain-anterior segment optical coherence tomography (SD-AS-OCT).This cross-sectional observational study includes 240 eyes of 120 healthy individuals (60 men, 60 women). Each gender was divided into 4 equal groups according to age as follows (18-29 years), (30-44 years), (45-59 years), and (60-80 years). The CET in 17 points over a corneal diameter of 6.0 mm was measured in each subject by SD-AS-OCT. The regional thickness changes were compared in different age groups of each gender separately and the correlations between the CET, age, and gender were analyzed.The CET of the central cornea (2 mm), the paracentral and the midperipheral zones (2-5 and 5-6 mm, respectively) of all males and females groups demonstrates highly significant changes with age (P < .001) with no significant difference between males and females. The measured parameters in the 2 age groups below 45 and above 45 years old revealed statistically significant difference with lower values in the elderly group (P < .001).The CET became thinner with age in the central, paracentral, and midperipheral zones in both genders and there is no difference between males and females. These findings could be valuable in refractive surgeries especially in age over 45.