Prevalence of Keratoconus on Screening of Egyptian LASIK Candidates: A Retrospective Multicenter Study.

PURPOSE: This is a retrospective multicenter study to report the incidental discovery of keratoconus (clinical and subclinical) in a screening of laser vision correction (LVC) surgery candidates. METHODS: This retrospective multicenter study was conducted on patients presenting for LVC in four Egyptian governorates (Cairo-Giza-6th of October-Beni Suef) during the year 2018. The patients were examined using the Pentacam HR (OCULUS Optikgeräte GmbH, Wetzlar, Germany) or Sirius (Costruzione Strumenti Oftalmici, Italy). The following parameters were evaluated: the axial curvature map, keratometry (Kmax and K2 on the posterior surface), minimum corneal thickness, anterior elevation, posterior elevation, Baiocchi-Calossi -Versaci index (Sirius), index of height decentration, and BAD-D (Pentacam). The prevalence of keratoconus cases was reported and data were analyzed. RESULTS: A total of 46 out of 782 candidates presenting for LVC in 2018 were incidentally discovered as clinical or subclinical keratoconus cases and were excluded from performing the LVC procedure. CONCLUSION: Screening of LVC candidates for keratoconus is a crucial tool to detect the incidence of the disease in the Egyptian population.

Correlation Between Myopic Refractive Error, Corneal Power and Central Corneal Thickness in the Egyptian Population.

PURPOSE: To find out the correlation between myopic refractive error, corneal power and central corneal thickness (CCT) in the adult Egyptian population. METHODS: A retrospective observational cross-sectional study in which we analyzed the preoperative data of 1401 Egyptian myopic patients (1401 eyes) who underwent keratorefractive procedures between 2016 and 2019 in a private eye surgery center. RESULTS: Mean age of patients was 28.1± 5.79 years (range 18-40). Mean CCT in the Egyptian population sample in our study was 539.23± 32.24. Only the corneal power parameters (flat K, steep K and average K) showed a statistically significant difference (p-value <0.001) between males and females. A statistically significant and weak positive correlation of average K with the absolute value of refractive astigmatism (r = 0.063, p-value = 0.018), and between myopic error with average K (r = 0.136, p-value <0.001) was found. CONCLUSION: Among the myopic adult Egyptian population, the greater the myopic error measured, the steeper the cornea, with a weak positive correlation between refractive error and corneal power.

Dexmedetomidine as an Additive to Local Anesthesia for Decreasing Intraocular Pressure in Glaucoma Surgery: A Randomized Trial.

BACKGROUND: Nowadays, the peribulbar block is used as a tool in glaucoma surgery. As a side effect, it increases intraocular pressure that raises the need for adjuvant medication to overcome this problem in the diseased eye. Dexmedetomidine has proven to decrease intraocular pressure (IOP) in the non-glaucomatous eye. OBJECTIVES: In a triple-blinded randomized study, dexmedetomidine as an adjuvant to the peribulbar block was used to decrease IOP in the diseased eye. METHODS: We randomized 98 eyes to three groups, including D50 (35 eyes) with dexmedetomidine 50 µg, D25 (33 eyes) with dexmedetomidine 25 µg, or control group (C) (30 eyes) with the plain peribulbar block. The study was randomized triple-blinded, aiming at testing the effect of dexmedetomidine on IOP after block injection. RESULTS: The pre-injection IOP was 27.71 ± 2.52, 27.25 ± 3.53, and 26.2 ± 3.57 mmHg in groups D50, D25, and C, respectively, then increased to 29.71 ± 1.69, 30.25 ± 2.36 and 29.4 ± 3.756 in groups D50, D25 and C, respectively, with P >0.05. The pressure decreased after the surgery to 10.86 ± 1.478 in group D50, 10.75 ± 1.63 in group D25, and 10.6 ± 1.589 in group C, with no statistical differences (P > 0.05) between the groups. CONCLUSIONS: Dexmedetomidine did not decrease IOP in the glaucomatous eye.

Prevalence of Subclinical Keratoconus Among Pediatric Egyptian Population with Astigmatism.

PURPOSE: To report the prevalence of subclinical keratoconus (KC), and KC suspects, in pediatric Egyptian population with astigmatic error ≥2 diopters (D), with the use of CSO Sirius tomographer. METHODS: A cross-sectional study that included all the children aged 6-18 years with an astigmatic error of ≥2 D who attended the pediatric ophthalmology clinic for routine checkups during the period between March 2017 and December 2017 was done. All subjects underwent comprehensive ophthalmic examination, and corneal imaging using CSO Sirius instrument, a pentacam with Scheimpflug technology. RESULTS: There were 547 subjects enrolled in our study. Mean age was 11.34 ± 3.03 (range 6-18) years. There were 278 subjects (50.8%) between 6 and 12 years, and 269 subjects (49.2%) between 12 and 18 years. Males represented 48.4% and females represented 51.6% of patients. Among all the subjects, there were 26 (4.8%) KC patients, 24 (4.4%) KC suspects, and 497 (90.9%) were normal. CONCLUSION: Prevalence of subclinical KC among pediatric age group with astigmatism is relatively high, hence the importance of corneal tomography screening of children with astigmatic error ≥2 D.

Chandelier-assisted scleral buckling using wide angle viewing contact lens for pseudophakic retinal detachment repair.

AIM: To evaluate a modified technique for scleral buckling (SB) in pseudophakic retinal detachment (RD). METHODS: A retrospective non-comparative study included 21 consecutive eyes with uncomplicated pseudophakic RD that was repaired by chandelier assisted SB using wide angle viewing (WAV) contact lens. Segmental tire alone was used in 5 eyes (23.81%), and combined with encircling band in 7 eyes (33.33%). Radial sponge alone was used in 3 eyes (14.29%) and combined with encircling band in 6 eyes (28.57%). RESULTS: Primary success rate was (90.48%). External drainage of subretinal fluid was performed in 8 eyes (38.1%). Intraoperative complications included vitreous prolapse at chandelier sclerotomy site in 4 eyes (19.05%) and localized subretinal hemorrhage at drainage site in one eye (4.76%). No case of intraocular lens (IOL) displacement, retinal incarceration or iatrogenic retinal tear was detected. Postoperative complications included choroidal detachment in one eye (4.76%), elevated intraocular pressure in 2 eyes (9.52%), epiretinal membrane formation in one eye (4.76%) and proliferative vitreoretinopathy in 3 eyes (14.29%). Mean postoperative corrected distance visual acuity was 0.7±0.3 logMAR units. CONCLUSION: Chandelier-assisted SB using WAV contact lens is a reliable technique for repairing selected cases of simple pseudophakic RD.

Prospective, randomized contralateral eye study of accelerated and conventional corneal cross-linking in pediatric keratoconus.

PURPOSE: To compare the outcomes of two different cross-linking (CXL) protocols, in pediatric keratoconus eyes. MATERIALS AND METHODS: In this prospective randomized contralateral eye interventional study, 68 eyes of 34 patients, 9-16 years old, underwent CXL and enrolled between October 2011 and October 2013. Group A represents conventional riboflavin-ultraviolet A (UVA)-induced CXL with 30 min of exposure to UVA irradiation of 3 mW/cm2. Group B represents accelerated cross-linking with 5 min of continuous UVA irradiation of 18 mW/cm2. In either group, total energy delivered was adjusted to 5.4 J/cm2. Follow-up of all patients was accomplished throughout the postoperative 3 years, and the data from the preoperative, 12, 24, and 36 months visits were analyzed and compared in both groups. Uncorrected visual acuity, corrected distance visual acuity, steepest keratometry (Kmax), corneal astigmatism (simulated K), total wavefront aberrations, central corneal thickness (CCT), corneal densitometry, manifest refraction spherical equivalent, and endothelial cell density (ECD) were evaluated at baseline, 12, 24, and 36 months post-CXL. RESULTS: At 1-year assessment, the mean value of UCVA, CDVA, and Kmax showed a statistically significant difference between both groups, without any documented change in the variables throughout the remaining follow-up (1-3-year) period. Twelve months postoperatively, mean LogMAR UCVA and CDVA were (0.11 ± 1.60) and (0.03 ± 1.60), respectively, in accelerated CXL group, compared to conventional CXL group values of (0.20 ± 1.00) and (0.06 ± 1.22), showing a statistically significant difference (P < 0.05). Mean Kmax in accelerated CXL group (45.47 ± 0.44) showed a statistically significant difference (P < 0.05) compared to conventional CXL group (46.41 ± 1.59) at 12 months post-CXL. On the other hand, wavefront aberrations, simulated K, corneal densitometry, ECD, and CCT changes showed nonstatistically significant difference in conventional CXL group, compared to accelerated CXL group (P > 0.05) throughout the follow-up course. CONCLUSIONS: Both conventional and accelerated CXL improved UCVA and CDVA, attenuated disease progression, and reduced corneal steepness and wavefront aberrations at 1, 2, and 3 years postoperatively. In no case did keratoconus progress over the 36-month follow-up.

ICL versus SMILE in management of anisometropic myopic amblyopia in children.

OBJECTIVE: We compare the predictability, safety, and efficacy of posterior chamber phakic intraocular lens (PCpIOL) versus small-incision lenticule extraction (SMILE) for correcting myopic anisometropia in amblyopic children. METHODS: A prospective randomized study enrolled 30 children, aged 4-12 years, with unilateral myopic anisometropic amblyopia whose refraction ranged between -5 and -10 diopters (D) and myopic astigmatic error -1 to -6 D. Patients were subdivided into group A for unilateral PCpIOL implantation and implantable collamer lens (Visian ICL/TICL) of V4C design and group B for SMILE procedure. Pre- and postoperative corrected distance visual acuity (CDVA), uncorrected visual acuity, and cycloplegic refractive spherical equivalent (CRSE) were performed in all patients and compared between both groups. Follow-up was for at least 18 months. RESULTS: Of the 15 children in group A, 12 (80%) revealed prevention of amblyopia and improvement in CDVA of 3-6 lines, and 3 children (20%) gained 1-3 lines. In group B, 6 (40%) eyes gained 3-5 lines, 6 (40%) eyes gained 1-3 lines, and 3 (20%) children gained 0-1 line. Stereoacuity improved in 93.33% of cases. Mean CRSE decreased in both groups 18 months postoperative (p < 0.001). Improvement in stereoacuity occurred in 86.66% of cases. CONCLUSIONS: To eliminate significant anisometropic myopia in children who are noncompliant with conventional treatment, PCpIOL or SMILE may be considered as alternative modalities of treatment. Being an extraocular procedure, SMILE was found to be a safer procedure with fewer and less serious complications compared to ICL.

Implantable Collamer Lens in the Management of Pseudophakic Ametropia.

PURPOSE: To assess Visian Implantable Collamer Lens (ICL) (STAAR Surgical, Monrovia, CA) implantation in the ciliary sulcus to correct pseudophakic ametropia in patients who are not candidates for a keratorefractive procedure. METHODS: The authors performed a prospective non-comparative case series study of 18 patients (age: 48 to 61 years) with refractive surprise after phacoemulsification. Patients underwent implantation of a piggyback collagen copolymer lens: V4C design in 16 myopic eyes and V4B design in 2 hyperopic eyes. The position and vault of the ICLs were documented at all control visits clinically and with Pentacam (Oculus Optikgeräte, Wetzlar, Germany). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), intraocular pressure (IOP), and endothelial cell count were recorded at baseline and 1 week and 1, 6, 12, and 18 months postoperatively. RESULTS: The MRSE improved from -3.08 ± 2.37 diopters (D) preoperatively to -0.44 ± -0.23 D postoperatively, corrected with a mean ICL power of -3.20 ± 2.90 D. The mean UDVA improved from 1.03 ± 0.12 logMAR preoperatively to 0.05 ± 0.06 logMAR postoperatively (P = .00), whereas CDVA improved from 0.47 ± 0.03 logMAR preoperatively to -0.006 ± 0.02 logMAR (P = .001) postoperatively. None of the cases developed interlenticular opacification throughout the 18-month follow-up. The mean ICL vault measured by Scheimpflug tomography was 451.27 ± 178.5 µm. Acute IOP elevation with anterior uveitis developed in 2 eyes and was controlled by topical steroids and a beta-blocker. CONCLUSIONS: Sulcus implantation of the secondary ICL to correct pseudophakic refractive error was safe, predictable, and well tolerated in all studied eyes. [J Refract Surg. 2017;33(8):532-537.].

V4B implantable collamer lens versus Intacs corneal rings to manage anisometropic myopic amblyopia in children.

OBJECTIVE: To compare the safety and efficacy of phakic intraocular lens (PIOL) versus intrastromal corneal ring segments (Intacs), for correcting high myopic anisometropia in amblyopic children. DESIGN: Nonrandomized prospective multi-center study. PARTICIPANTS: Thirty children, aged between 4 and 12 years, with unilateral high myopic anisometropic amblyopia were included in this study. METHODS: Patients who were prospectively subdivided into group A, with mean preoperative manifest refraction spherical equivalent (MRSE) of -12.96 ± 4.17 D, underwent unilateral phakic posterior chamber intraocular lens implantation. Patients with mean preoperative MRSE of -8.60 ± 1.16 D in group B were treated by Intacs corneal rings. Pre- and postoperative visual acuity, ocular examination, stereoacuity, axial biometry measurements, cycloplegic refraction, and endothelial cell counts were performed in all patients. RESULTS: Group A revealed prevention of amblyopia with improvement in spectacle-corrected distance visual acuity, where 4-6 lines were achieved in 77% of children, 2-3 lines in 4%, and just 0-1 lines restricted to 19% of children. Improvement in stereoacuity was noted in 93.33% of group A cases, whereas group B showed fewer cases of successfully improved vision, with 4-6 lines in 70% of children, 2-3 lines in 3%, and just 0-1 lines restricted to 27% of children. Improvement in stereoacuity was noted in 86.66% of cases. Two cases of cataract and 1 case of glaucoma with 1 case of uveitis were noted in the implantable contact lens (ICL) group. CONCLUSIONS: Posterior chamber PIOLs or Intacs may provide a safe alternative in treating anisometropic myopic patients. Intacs implantation is safer with fewer complications than ICL. However, ICL implantation is advantageous over the corneal ring segment procedure owing to the wide range of errors to correct.

Primary Outcomes of Accelerated Epithelium-Off Corneal Cross-Linking in Progressive Keratoconus in Children: A 1-Year Prospective Study.

PURPOSE: To evaluate corneal transparency following accelerated collagen cross-linking (ACXL) in pediatric keratoconus. DESIGN: A prospective interventional case series. METHODS: This study included 47 eyes (25 patients), aged 9-14 years, with documented progressive keratoconus. After applying 0.1% riboflavin drops, ACXL was performed. Assessment included corrected distance visual acuity (CDVA), uncorrected visual acuity (UCVA), corneal haze, and corneal densitometry in grayscale units (GSU). RESULT: The mean baseline and corneal densitometry peaked at 3 months post-ACXL while central and posterior densitometry showed a statistically significant increase (P < 0.05) and peaked at 8 months postoperatively. By 12 months, densitometry in all corneal layers (P ≥ 0.99) and concentric zones (P ≥ 0.97) reached near baseline values. Slit-lamp graded haze peaked at 1 month to 1.82 ± 0.65 (P < 0.05) and declined to near baseline at 12 months (0.39 ± 0.58). There was a statistically significant increase in the mean UCVA and CDVA at 12 months. CONCLUSION: Total and anterior corneal densitometry peaked after 3 months, while central and posterior densitometry peaked after 8 months. Maximum haze was at 1 month post-ACXL. All corneal layers, concentric zone densitometry and haze reached near baseline values after 1 year. Scheimpflug densitometry showed weak correlation with CDVA over the 12-month follow-up period (r = -0.193).

Management of pseudophakic myopic anisometropic amblyopia with piggyback Visian® implantable collamer lens.

PURPOSE: To assess the outcomes of sulcus implantation of the Visian® implantable collamer lens (ICL) to correct pseudophakic myopic anisometropic amblyopia with myopic shift and/or primary refractive overcorrection. METHODS: Prospective case series enrolled 14 pseudophakic eyes of 14 patients, 5-9 years old, with history of cataract surgery and primary in the bag-intraocular lenses (IOL) implantation, followed by myopic shift and/or refractive overcorrection and anisometropic amblyopia of variable degrees. All cases had implantation of a piggyback ICL/toric ICL, to correct the myopia/myopic astigmatism. Preoperatively, we evaluated the uncorrected distance visual acuity (UCVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), intraocular pressure (IOP) and endothelial cell density (ECD). We assessed the position and vaulting of the ICLs on slit lamp examination and confirmed by Scheimpflug tomography. Postoperative follow-up was at 1st week and 1, 3, 6, 9, 12, 18 and 24 months. RESULTS: Uncorrected distance visual acuity improved in all cases, and CDVA improved in 11 amblyopic eyes (2-4 lines). There was no evidence of interlenticular opacification (ILO) throughout the 2-year follow-up. Two cases were complicated with early postoperative acute elevation of IOP and were controlled with topical beta-blockers. Postoperative acute anterior uveitis occurred in six eyes and controlled by topical steroids. Implantable collamer lens (ICL) vault was measured using Pentacam, with mean value of 470 ± 238 µm. CONCLUSION: Sulcus implantation of the secondary piggyback ICL to correct unilateral pseudophakic myopic refractive error in children was safe, efficient, predictable and well tolerated in management of anisometropic amblyopia in all eyes.

Anterior Chamber Angle Evaluation following Phakic Posterior Chamber Collamer Lens with CentraFLOW and Its Correlation with ICL Vault and Intraocular Pressure.

Purpose. To assess intraocular pressure (IOP), lens vaulting, and anterior chamber (AC) angle width, following V4C implantable Collamer lens (ICL) procedure for myopic refractive error. Methods. A prospective case series that enrolled 54 eyes of 27 patients that were evaluated before and after V4C phakic posterior chamber Collamer lens implantation for correction of myopic refractive error. Preoperative measurement of IOP was done using Goldmann applanation tonometer and anterior chamber angle width using both Van Herick slit lamp grading system and Scheimpflug tomography imaging (Oculus Pentacam). Follow-up of the aforementioned variables was at 1, 6, and 18 months postoperatively, together with ICL vault measurements. Results. The mean baseline IOP of 11.69 ± 2.15 showed a statistically significant (P = 0.002) increase after 1 month that remained unchanged at 6 and 18 months postoperatively, with mean value of 16.07 ± 4.12, 16.07 ± 4.10, and 16.07 ± 4.13, respectively. Pentacam AC angle width showed a statistically significant decrease at 1 (P = 0.025), 6 (P = 0.016), and 18 (P = 0.010) months postoperatively, with mean preoperative value of 40.14 ± 5.49 that decreased to 25.28 ± 5.33, 25.46 ± 5.44, and 25.49 ± 5.38, at 1, 6, and 18 months, respectively. Mean ICL vault showed moderate correlation with Pentacam AC angle width at 1 (r = -0.435) and 6 (r = -0.424) months. Conclusion. V4C ICL implantation resulted in decrease in AC angle width and increase in IOP, within acceptable physiological values at all time points.

Subthreshold diode-laser micropulse photocoagulation as a primary and secondary line of treatment in management of diabetic macular edema.

BACKGROUND: The purpose of this study was to evaluate subthreshold diode-laser micropulse (SDM) photocoagulation as a primary and secondary line of treatment for clinically significant diabetic macular edema (CSDME). METHODS: In this prospective nonrandomized case series, 220 cases of nonischemic CSDME were managed primarily and secondarily by SDM photocoagulation on a 15% duty cycle with a mean power of 828 mW and a spot size of 75-125 µm. SDM treatment was repeated at 3-4-month intervals if residual leakage was observed. Additional intravitreal pharmacologic therapy was used according to the response. Follow-up varied from 12 to 19 (mean 14±2.8) months. Novel software designed by the authors was used to record the subvisible threshold laser applications and their parameters on the fundus image of the eye. Evaluation of the results of treatment was done using fluorescein angiography and optical coherence tomography (OCT). Primary outcome measures included changes in visual acuity and foveal thickness at OCT. Secondary outcome measures included visual loss of one or more Snellen lines and laser scars detectable on fundus biomicroscopy or fluorescein angiography. RESULTS: In the primary treatment group, there was significant improvement or stabilization of visual acuity after the first 3-4 months, which was stable thereafter. Visual acuity was stable in the secondary treatment group. A corresponding reduction of macular thickness on OCT was noted during the follow-up period in both groups. Additional therapy included repeat SDM photocoagulation, intravitreal injection of triamcinolone, and pars plana vitrectomy. Laser marks seen as changes in retinal pigment epithelium on fundus biomicroscopy and fluorescein angiography were noted in 3.3% and 5.7% of cases. Our novel software could accurately record the location of all SDM-invisible applications. CONCLUSION: Micropulse laser is an effective minimal intensity therapy that offers the clear advantage of minimizing or avoiding laser-induced visible retinal burn/scarring while reducing the foveal thickness in the management of selected cases of CSDME. Future prospective studies should include the use of SDM photocoagulation as a combined minimally invasive therapy to consolidate the prompt but temporary effects of anti-vascular endothelial growth factor or anti-inflammatory agents. Virtual localization of SDM-invisible applications using our proprietary software could be used to guide further retreatments.