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Abstract Permeability prediction and distribution is very critical for reservoir modeling process. The conventional method for obtaining permeability data is from cores, which is a very costly method. Therefore, it is usual to pay attention to logs for calculating permeability where it has massive limitations regarding this step. The aim of this study is to use unique artificial intelligence (AI) algorithms to tackle this challenge and predict permeability in the studied wells using conventional logs and routine core analysis results of the core plugs as an input to predict the permeability in non-cored intervals using extreme gradient boosting algorithm (XGB). This led to promising results as per the R 2 correlation coefficient. The R 2 correlation coefficient between the predicted and actual permeability was 0.73 when using the porosity measured from core plugs and 0.51 when using the porosity calculated from logs. This study presents the use of machine-learning extreme gradient boosting algorithm in permeability prediction. To our knowledge, this algorithm has not been used in this formation and field before. In addition, the machine-learning model established is uniquely simple and convenient as only four commonly available logs are required as inputs, it even provides reliable results even if one of the required logs for input is synthesized due to its unavailability.

Background Intracorneal ring segment (ICRS) implantation in combination with corneal collagen cross-linking (CXL) has shown promising results in improving the visual acuity and reducing refractive errors, but long-term results are lacking. Aim To evaluate the long-term outcomes (>5 years) of simultaneous CXL and femtosecond laser-assisted intracorneal stromal ring segment implantation for management of keratoconus. Design This was a noncomparative, noncontrolled retrospective single-center study. Patients and methods The study included 50 eyes of 37 patients with keratoconus who underwent simultaneous CXL and ICRS implantation and were followed up for at least 5 years regarding visual acuity, refraction, and corneal imaging. Results Best-corrected visual acuity showed statistically significant improvement, with mean changed from 1.07±0.41 to 0.40±0.30 LogMAR. The results showed significant improvement also after 5 years. The spherical equivalent also was significantly improved from a mean of −4.61±4.37 D to a mean of −1.41±−1.49 D. Keratometric readings also showed improvement of both K1 and K2. The mean K1 improved from a mean of 49.6±6.76–47.78±6.17 D, and the mean K2 improved from 55.04±7.34 to 52.67±7.38. The results were stable, with no statistically significant change after 5 years. Conclusions Simultaneous CXL and femtosecond laser-assisted ICRS is effective and stable for both visual outcome and refraction in patients with keratoconus.

Purpose The aim of this study was to determine the prevalence and types of color vision deficiency (CVD) among primary school students in Alexandria, Egypt. Setting This study was carried out at three primary schools in Alexandria, Egypt. Patients and methods This cross-sectional study was carried out among three primary school students in Alexandria, Egypt. Ocular examination including visual acuity and color vision testing with Ishihara plates (38-plate edition) was performed for all the students included. Further assessment using the Farnsworth–Munsell 100-hue test was performed for students who failed the Ishihara plates test. Results A total of 1000 (495 males and 505 females) school students were screened for CVD. The mean age of the students was 9±2.16 years. The overall prevalence of CVD was 1.9%, with a prevalence of 2.8 and 0.9% in males and females, respectively, a statistically significant difference (P=0.04). Among the CVD students, 36.8% had deuteranopia, 31.5% had deuteranomaly, 26.3% had protanopia, and 5.3% had tritanopia. Conclusion The prevalence of CVD was 1.9%, with a male predominance, among primary school students in Alexandria. Deutan color vision defects were the most prevalent.

Purpose The aim of this study was to evaluate the age and its relation to lid laxity and ocular surface disorders as well as the lid laxity prevalence in an elderly Egyptian population. Setting The study was conducted at the Department of Ophthalmology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt. Patients and methods The study included 400 patients presenting to the Outpatient Eye Clinic of Alexandria Main University Hospital, Alexandria, Egypt, from April 2018 to April 2019. A cross-sectional survey of patients above 55 years old was done. Clinical data were gathered from a questionnaire. Upper and lower eyelid laxity was clinically graded. In addition, tear breakup time test was done to evaluate dryness. Results The study was conducted on 799 eyes. The prevalence of lid laxity in the right lower and upper lids was 51.1 and 14.8%, respectively, whereas in left lower and upper lids, it was 50 and 14.7%, respectively. There was a negative significant correlation between tear breakup time and lid laxity in the right lower and upper lids and in the left lower lid (P

Purpose The aim of this study was to evaluate the tear film and the changes in ocular surface in type 2 diabetic patients. Patients and methods This is a prospective, cross-sectional, observational, hospital-based study of 100 participants (200 eyes). They included 50 diabetic patients (100 eyes) and 50 healthy controls (100 eyes), of either sex above 40 years old, who were evaluated at Alexandria General Eye Hospital, Alexandria, Egypt. History was taken from all participants including ocular surface disease index questionnaire. All participants underwent full ophthalmological examination, Schirmer’s test, tear film breakup time, corneal staining, and rose Bengal staining tests. Results When compared with the healthy controls, diabetic patients showed significantly reduced Schirmer’s test, tear breakup time measurements, and higher grades of corneal and rose Bengal staining (P

Purpose. To assess the safety and stability in cases of small incision lenticule extraction with collagen cross-linking (SMILE Xtra). Methods. This study was a retrospective interventional comparative study that included 60 eyes of 30 patients divided equally into two groups: SMILE Xtra and SMILE alone. The inclusion criteria were patients >18 years of age, myopic error >6 D, thinner cornea

Purpose The aim of this study was to compare electron microscopic morphological images of the posterior surface of corneal lenticules removed during femtosecond laser small-incision lenticule extraction (SMILE) with free corneal caps created using a mechanical microkeratome. Design An in-vitro comparative study was carried out including 30 human corneal lenticules from 15 patients who underwent bilateral SMILE refractive procedure (SMILE group) using the 500 kHz VisuMax femtosecond laser and 20 cadaveric donor corneas that were cut creating free caps using the Moria M2 microkeratome. Setting The present study was carried out at Roayah Vision Correction Center and Faculty of Science, Alexandria University. Participants and methods A total of 15 SMILE lenticules and 15 microkeratome free caps were examined by scanning electron microscopy (SEM), and another 15 SMILE lenticules and five microkeratome free caps were examined by transmission electron microscopy. The JEOL JSM-5300LV SEM was used for observations. A new scoring system was used for comparison. Results The surface and edge of SMILE lenticules showed more roughness in the form of tissue bridges, dome-shaped elevations, more cavitational changes, and tiny tissue fragments compared with the undersurface of free corneal microkeratome caps, but the difference was not statistically significant on SEM (P=0.40654). Conclusion SMILE induces corneal surface roughness and structural changes that are slightly more pronounced than those induced by the microkeratome. The observed changes may cause surgically induced optical aberrations. Energy settings still need further adjustment to be able to create reproducible, predictable smooth surfaces in lenticules of SMILE cases.

Purpose The aim of this study was to evaluate the surface quality of corneal lenticules at variable corneal depths in cases of small incision lenticule extraction using scanning electron microscopy. Patients and methods Forty eyes of 20 myopic patients were included. One eye was randomly assigned for lenticules at 100 µm depth (group I), whereas the other eye was assigned for lenticules at 160 µm depth (group II). The VisuMax femtosecond laser system was used for the procedure. An established scoring system and a new scoring system at higher magnification levels for surface regularity were used. Results The mean overall diameter of the lenticules as seen on electron microscopy was 6.54±0.17 and 6.73±0.20 mm in group I and group II, respectively (P=0.003). In both groups, around 50% of cases showed a smooth surface at ×10 magnification. The mean score was 14.90+1.74 and 13.25+2.77 in group I and group II, respectively (P=0.031). Conclusion The VisuMax femtosecond laser system creates predictable good-quality surface refractive corneal lenticules at superficial depth. Deeper corneal lenticules showed more irregular surfaces, especially at higher magnification levels. Energy settings still need further adjustment to be able to create deeper predictable lenticules in small incision lenticule extraction cases.

Ahmed M Emarah1, Shawky M El-Haggar2, Ihab A Osman2, Abdel Wahab S Khafagy21Departments of Ophthalmology, 2Andrology and Sexology, Cairo University Hospital, EgyptObjectives: Arteriogenic erectile dysfunction (ED) is a target organ disease of atherosclerosis, and therefore might be a predictor of systemic atherosclerosis. Being systemic, it might be possible to evaluate the extent of atherosclerosis from retinal vascular findings. We investigated the possible correlation between penile cavernosal artery blood flow and retinal vascular findings in patients with arteriogenic ED.Patients and methods: Sixty patients with ED were divided according to the peak systolic velocity (PSV) in their penile cavernosal arteries into two groups; Group A included 30 patients with PSV less than 25 cm/sec, and Group B included 30 patients with PSV more than 35 cm/sec. Blood flow in the penile cavernosal artery was measured with color Doppler ultrasonography. All patients were assessed by ocular fundus examination under amydriatic conditions to evaluate retinal vascular atherosclerotic changes using Hyman’s classification.Results: Evidence of retinal vascular atherosclerotic changes was found in 19 patients (63.3%) in Group A and in 10 patients (33.3%) in Group B.Conclusions: Our study confirms the possibility of predicting penile arterial vascular status in patients with ED from their retinal vascular findings by using amydriatic simple, practical funduscopy.Keywords: erectile dysfunction, atherosclerosis, retinal vascular atherosclerosis

BACKGROUND: Surgery of radiation-induced cataracts in children with retinoblastoma (RB) is a challenge as early intervention is weighted against the need to delay surgery until complete tumour control is obtained. This study analyses the safety and functional results of such surgery. METHODS: In a retrospective, non-comparative, consecutive case series, we reviewed medical records of RB patients ≤14 y of age who underwent either external beam radiotherapy or plaque treatment and were operated for radiation-induced cataract between 1985 and 2008. RESULTS: In total, 21 eyes of 20 RB patients were included and 18 out of the 21 eyes had Reese-Ellsworth stage V or ABC classification group D/E RB. Median interval between last treatment for RB and cataract surgery was 21.5 months, range 3–164 months. Phacoaspiration was performed in 13 eyes (61%), extra-capsular cataract extraction in 8 (39%) and intraocular lens implantation in 19 eyes (90%). The majority of cases, 11/21 (52%), underwent posterior capsulorhexis or capsulotomy and 6/21 (28%) an anterior vitrectomy. Postoperative visual acuity was ≥20/200 in 13 eyes and <20/200 in 5 eyes. Intraocular tumour recurrence was noted in three eyes. Mean postoperative follow up was 90 months±69 months. CONCLUSIONS: Modern cataract surgery, including clear cornea approach, lens aspiration with posterior capsulotomy, anterior vitrectomy and IOL implantation is a safe procedure for radiation-induced cataract as long as RB is controlled. The visual prognosis is limited by initial tumour involvement of the macula and by corneal complications of radiotherapy. We recommend a minimal interval of 9 months between completion of treatment of retinoblastoma and cataract surgery. [ABSTRACT FROM AUTHOR]

Permeability prediction and distribution is very critical for reservoir modeling process. The conventional method for obtaining permeability data is from cores, which is a very costly method. Therefore, it is usual to pay attention to logs for calculating permeability where it has massive limitations regarding this step. The aim of this study is to use unique artificial intelligence (AI) algorithms to tackle this challenge and predict permeability in the studied wells using conventional logs and routine core analysis results of the core plugs as an input to predict the permeability in non-cored intervals using extreme gradient boosting algorithm (XGB). This led to promising results as per the R2 correlation coefficient. The R2 correlation coefficient between the predicted and actual permeability was 0.73 when using the porosity measured from core plugs and 0.51 when using the porosity calculated from logs. This study presents the use of machine-learning extreme gradient boosting algorithm in permeability prediction. To our knowledge, this algorithm has not been used in this formation and field before. In addition, the machine-learning model established is uniquely simple and convenient as only four commonly available logs are required as inputs, it even provides reliable results even if one of the required logs for input is synthesized due to its unavailability. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effectiveness of ICI of platelet‐rich plasma (PRP) in addition to daily oral tadalafil intake in diabetic erectile dysfunction (ED) patients non‐responding to PDE5 inhibitors. Overall, 48 patients complaining of ED non‐responding to on‐demand PDE5 inhibitors were allocated into 2 equal groups, diabetics and non‐diabetics that were given a daily dose of 5 mg tadalafil plus vardenafil 20 mg on demand during the study besides being subjected to 3 doses of ICI of PRP, 4 weeks apart. Responses to on‐demand PDE5 inhibitors, International index of erectile function‐5 (IIEF‐5) score, erection hardness scores (EHS) and pharmaco‐dynamic duplex studies were assessed. After PRP injections, 33% and 50% of cases were satisfied with on‐demand PDE5 inhibitors, respectively, whereas 41% and 66% of them showed improved EHS response. Compared with baseline scores, the mean IIEF‐5 scores were significantly improved after PRP therapy in the diabetic ED group (12.1 vs. 8.04, p = 0.003) as well as in the non‐diabetic ED group (14.8 vs. 10.2, p = 0.001) linked to pharmaco‐penile duplex readings. Both good and fair diabetic control exhibited significant responses to ICI therapy of PRP compared with bad controlled cases. The significant improvement included; the IIEF‐5 score increase (86.7%, 126% vs. 16.1%), improved EHS as well as penile duplex readings. Baseline HbA1C demonstrated a significant negative correlation with IIEF‐5 score before (p = 0.019) and after PRP therapy (p = 0.002) respectively. It could be concluded that ICI of PRP could be an effective therapy for treating ED patients non‐responding to on‐demand oral PDE5 treatment. [ABSTRACT FROM AUTHOR]

The G-ROP model was proposed to improve the retinopathy of prematurity (ROP) screening efficiency. It is based on gestational age, birth weight and postnatal weight gain. The current study aimed to validate the G-ROP model's ability to predict ROP in cohorts of premature infants from Egypt and the United Kingdom (UK). We retrospectively reviewed the records of preterm infants born between 1st of January and 30th of June 2018 with a known outcome for ROP screening and regular weight measurements until day 39 after birth. We applied the G-ROP model to the study group and calculated the sensitivity of the model for detecting Early Treatment of ROP (ETROP) study type 1 ROP and for any ROP and calculated the reduction of the number of infants requiring ROP screening by the model application. We applied the G-ROP model on 605 infants (504 from Egypt and 101 from the UK). The model successfully predicted all type 1 ROP cases (100% sensitivity) in both cohorts (95% confidence interval [CI], 91.1–100% in the Egyptian cohort and 65.5–100% in the UK cohort). The model reduced the number of infants requiring screening by 14.1% in the Egyptian cohort and 21.8% in the UK cohort. The G-ROP model was successfully validated for detecting type 1 ROP and in both cohorts from Egypt and the UK. [ABSTRACT FROM AUTHOR]

Purpose: To report on the corneal biomechanical characteristics, namely the corneal hysteresis (CH), corneal resistance factor (CRF), as well as the intraocular pressure (IOP) goldman compensated (IOPg), and the cornea compensated (IOPcc), using the ocular response analyzer (ORA) in different age groups in a cohort of normal individuals from the second decade to the seventh decade and beyond. Patients and methods: The study was a cross-sectional survey conducted on 997 eyes of 508 normal individuals presenting for a routine ophthalmic examination at Alexandria Main University Hospital in Alexandria University, Alexandria, Egypt. The study subjects were age stratified into decades (10–20, 21–30, 31–40, 41–50, > 50) and the ORA parameters (CH, CRF, IOPg, IOPcc) reported and stratified. Correlations were sought between the ORA parameters and the age, gender, and laterality. Results: The study was conducted on 997 (502 right) eyes of 508 (234 males) normal individuals. The mean ± SD ages of the study groups were 14.7 ± 3.2, 25.9 ± 3.0, 35.3 ± 2.8, 44.6 ± 2.9, and 61.1 ± 7.7 years. The mean ± SD of the CH in the study groups were 10.9 ± 2.4, 9.8 ± 1.5, 9.8 ± 1.4, 9.7 ± 1.7, and 9.5 ± 1.6 mmHg and of the CRF were 10.9 ± 2.4, 9.5 ± 1.7, 9.4 ± 1.8, 9.6 ± 1.9, and 9.6 ± 1.8 mmHg. A statistically significant negative correlation was found between age and each of CH and CRF. IOPcc demonstrated a fairly constant trend in the different age groups whereas IOPg demonstrated an initial decline followed by a gradual rise over time. Conclusion: The corneal biomechanical properties CH and CRF decrease with age. IOPg and IOPcc change minimally with age. [ABSTRACT FROM AUTHOR]

Purpose: To study the astigmatic correction of high post-keratoplasty astigmatism using Femtosecond laser (FSL)-assisted Arcuate Keratotomy (FS-AK). Methods: A prospective interventional cohort study. We enrolled 17 eyes with high degree of irregular astigmatism, scheduled for FS-AK. FSL was used to perform paired arcuate incisions 1.00 mm inside the graft. Patients' uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and astigmatic change were recorded and followed up to 1 year after surgery. Vector analysis using Alpins' method was done to analyze the astigmatic correction. Results: FS-AK reduced the refractive astigmatism at final follow-up visit at 12 months (p = 0.0008, repeated-measures analysis of variance [ANOVA]). The procedure improved the UCVA over the follow-up period (p = 0.007, repeated-measures ANOVA), with a similar effect on the BCVA (p = 0.046, repeated-measures ANOVA). There was a mild correlation between the target-induced astigmatism and the surgically induced astigmatism (R2 = 0.245) with a tendency to overcorrect more than under correct the astigmatism. A constant rotational error in the counterclockwise direction was also detected. Conclusions: FS-AK improves the visual outcome and reduces the refractive cylinder in post-penetrating keratoplasty astigmatism. The predictability of astigmatism correction was variable in reducing post-keratoplasty astigmatism. Refinement of the treatment nomogram for such cases is highly recommended. [ABSTRACT FROM AUTHOR]

Purpose. To assess the safety and stability in cases of small incision lenticule extraction with collagen cross-linking (SMILE Xtra). Methods. This study was a retrospective interventional comparative study that included 60 eyes of 30 patients divided equally into two groups: SMILE Xtra and SMILE alone. The inclusion criteria were patients >18 years of age, myopic error >6 D, thinner cornea <520 microns, and abnormal corneal topography. Outcome data were recorded including uncorrected distance visual acuity and corrected distance visual acuity (UDVA and CDVA), manifest refraction spherical equivalent (MRSE), central corneal thickness, average keratometry, endothelial cell density, corneal resistance factor (CRF), and corneal densitometry. The follow-up period was 24 months. Results. There was a significant difference between the 2 groups regarding UDVA, CDVA, and MRSE at 1 month. In the SMILE Xtra group, 90% of eyes had postoperative UDVA of 20/20 and 97% had UDVA of 20/30 at 24 months. At 24 months, 26 eyes (87%) vs. 25 eyes (84%) were within ±0.50 D of attempted correction in SMILE Xtra and SMILE groups, respectively. Regarding stability, both groups showed improvement of MRSE at 1st month postoperatively and remained stable along the 24 months of follow-up. CRF and corneal densitometry were higher in the SMILE Xtra group along the whole follow-up period (p=0.001). Conclusion. Combining corneal cross-linking with SMILE procedure (SMILE Xtra) is a promising tool to prevent ectasia in high-risk patients. It is a safe and simple procedure that can be offered to patients undergoing SMILE with risk for ectasia. Trial registration no: PACTR201810577524718. [ABSTRACT FROM AUTHOR]

Background: Evaluating the corneal biomechanical changes using the Ocular Response Analyzer and the Corvis ST in eyes with incision lenticule extraction (SMILE) and laser assisted in situ keratomileusis (LASIK).Methods: This is a retrospective study that included 50 eyes equally divided into two groups. The first group included eyes that underwent SMILE procedure using VisuMax® 500 kHz laser system (Carl Zeiss Meditec, Jena, Germany) and the second group included eyes that underwent LASIK procedure using the EX500 Allegretto excimer laser platform (Wavelight GmbH, Erlangen, Germany). The Ocular Response Analyzer (ORA) and the Corvis ST (CST) measured the corneal biomechanical changes before and after the procedures.Results: The ORA showed significant decrease of corneal hysteresis (CH) and corneal resistance factor (CRF) in both groups postoperatively. The percentage of change of CH and CRF were found to be significantly higher in group II. There was no significant difference in the IOP with the ORA and the CST pre and postoperatively in either group. Using CST, the deformation amplitude and HC peak distances increased significantly in both groups. It was also noted that the mean percentage of change of the deformation amplitude was nearly five times higher in group II than group I.Conclusion: Both LASIK and SMILE substantially decreased the corneal biomechanical properties with greater reduction in the LASIK group. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to compare the postoperative corneal biomechanical properties between small incision lenticule extraction (SMILE) and other corneal refractive surgeries.Methods: A systematic review and meta-analysis were conducted. Articles from January 2005, to April 2019, were identified searching PubMed, EMBASE, Web of Science, and International Clinical Trials Registry Platform. Studies that compared SMILE with other corneal refractive surgeries on adult myopia patients and evaluated corneal biomechanics were included. Multiple effect sizes in each study were combined. Random-effects model was conducted in the meta-analysis.Results: Twenty-two studies were included: 5 randomized controlled trials (RCTs), 9 prospective and 6 retrospective cohort studies, and 2 cross-sectional studies. Using the combined effect of corneal hysteresis (CH) and corneal resistance factor (CRF), which were obtained from ocular response analyzer (ORA), the pooled Hedges' g of SMILE versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) was 0.41 (95% CI, 0.00 to 0.81; p = 0.049; I2 = 78%), versus LASIK was 1.31 (95% CI, 0.54 to 2.08; p < 0.001; I2 = 77%), versus femtosecond lenticule extraction (FLEX) was - 0.01 (95% CI, - 0.31 to 0.30; p = 0.972; I2 = 20%), and versus the group of photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (LASEK) was - 0.26 (95% CI, - 0.67 to 0.16; p = 0.230; I2 = 54%). The summary score of Corvis ST (CST) after SMILE was comparable to FS-LASIK/LASIK with the pooled Hedges' g = - 0.05 (95% CI, - 0.24 to 0.14; p = 0.612, I2 = 55%).Conclusions: In terms of preserving corneal biomechanical strength after surgeries, SMILE was superior to either FS-LASIK or LASIK, while comparable to FLEX or PRK/LASEK group based on the results from ORA. More studies are needed to apply CST on evaluating corneal biomechanics after refractive surgeries. [ABSTRACT FROM AUTHOR]