Ahmet Demirok

Comparison of corneal hysteresis and corneal resistance factor after small incision lenticule extraction and femtosecond laser-assisted LASIK: A prospective fellow eye study

PURPOSEnTo compare corneal hysteresis (CH) and corneal resistance factor (CRF) between eyes treated with small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (femto-LASIK).nnnSETTINGnBeyoğlu Eye Training and Research Hospital.nnnDESIGNnProspective comparative case series.nnnMETHODSnSixty eyes from 30 patients with bilateral myopia or myopic astigmatism were studied. Inclusion criteria were spherical equivalent of subjective manifest refraction (SE) <10diopters (D) and a difference ≤0.50D between the SEs of both eyes. One eye of each patient was treated with SMILE, and the fellow eye underwent femto-LASIK. Randomization was performed using a sealed envelope system. The main outcome measures were CH and CRF measured preoperatively and postoperatively (1 and 6 months).nnnRESULTSnPreoperative SE was similar in both groups (p=0.852). CH and CRF values were reduced postoperatively in both groups compared to their corresponding preoperative values (p<0.001). At the 6-month follow-up visit, the mean CH values in the SMILE and femto-LASIK groups were 8.95±1.47 and 9.02±1.27, respectively (p=0.852), and the mean CRF values were 7.77±1.37 and 8.07±1.26, respectively (p=0.380).nnnCONCLUSIONnCH and CRF decreased after SMILE. There were no differences between SMILE and femto-LASIK treatments in postoperative CH or CRF values.

Evaluation of corneal microstructure in keratoconus: a confocal microscopy study.

PURPOSEnTo compare the corneal microstructure in patients with manifest keratoconus (KCN), subclinical KCN, and topographically normal relatives of patients with KCN and in healthy controls.nnnDESIGNnProspective and cross-sectional study.nnnMETHODSnWe enrolled 145 subjects in the study. The participants were divided into 4 groups, based on clinical and topographical evaluation: the manifest KCN group (n = 30), the subclinical KCN group (n = 32), the KCN relatives group (n = 53), and the control group (n = 30). Corneal microstructure was assessed by corneal in vivo confocal microscopy in all of the individuals. Mean outcome measures were basal epithelial cell density, endothelial cell density, anterior keratocyte density, posterior keratocyte density, sub-basal nerve density, sub-basal nerve diameter, and stromal nerve diameter.nnnRESULTSnThe mean basal epithelial cell density, endothelial cell density, and sub-basal nerve diameter were not significantly different among the 4 groups (P = 0.057, P = 0.592, and P = 0.393, respectively). The mean anterior and posterior stromal keratocyte densities were significantly lower in the manifest group, in the subclinical group, and in the relatives group when compared with the control group (for both parameters; P < 0.001, P < 0.001, and P< 0.001, respectively). The mean stromal nerve diameter in the manifest group, subclinical group, and relatives group was significantly higher than in the control group (P = 0.001, P = 0.049, and P = 0.004, respectively).nnnCONCLUSIONnThe anterior and posterior stromal keratocyte densities were statistically lower and stromal nerve diameter was statistically higher in patients with manifest KCN, subclinical KCN, and topographically normal KCN relatives compared with controls. Confocal microscopy may be useful for the determination of early corneal microstructural changes before manifestation of typical or subtle topographic signs.

Comparison of efficacy between low-fluence and half-dose verteporfin photodynamic therapy for chronic central serous chorioretinopathy.

Purpose To compare the efficacy of low-fluence photodynamic therapy (PDT) and PDT with half-dose verteporfin in chronic central serous chorioretinopathy (CSC). Patients and methods The medical records of 64 eyes from 60 patients with chronic CSC were retrospectively reviewed; 36 eyes received low-fluence PDT (25 J/cm2) and 28 eyes received half-dose verteporfin PDT (3 mg/m2). The primary outcome measure was the proportion of eyes with complete resolution of subretinal fluid. Secondary outcome measures were the changes in best corrected visual acuity (BCVA) and central foveal thickness, and the proportion of eyes that showed an increase of ≥5 letters in BCVA at the last visit. Results The mean follow-up period was 12.5±4.3 months and 13.1±4 months in the low-fluence group and half-dose group, respectively (P=0.568). Thirty-three eyes (91.6%) in the low-fluence group and 26 eyes (92.8%) in the half-dose verteporfin group showed complete resolution of subretinal fluid (P=0.703). BCVA increased by a mean of 7.4 letters and 4.8 letters in the low-fluence group and half-dose group, respectively (P=0.336). Seventeen eyes (52.8%) in the low-fluence group and 14 eyes (50%) in the half-dose group experienced a gain of ≥5 letters in BCVA (P=0.825). In the low-fluence and half-dose verteporfin group, the mean baseline central foveal thickness was 351±90 μm and 341±96 μm, and significantly decreased to 188±61 μm and 181±47 μm, respectively (P<0.01). Conclusion Both treatments resulted in complete subretinal fluid resolution in most of the eyes, with significantly better visual acuity outcomes compared to baseline at the last visit.

Pain, wound healing and refractive comparison of mechanical and transepithelial debridement in photorefractive keratectomy for myopia: results of 1 year follow-up.

PURPOSEnTo compare the efficacy, safety and postoperative pain of mechanical versus transepithelial photorefractive keratectomy (PRK) techniques.nnnSETTINGnCornea and refractive surgery subspecialty.nnnDESIGNnProspective clinical trial.nnnMETHODSnThis prospective comparative study included 84 eyes of 42 patients with myopia who received mechanical PRK (m-PRK) in 1 eye and transepithelial PRK (t-PRK) in the contralateral eye. The mean patient age was 28.5±6.3 years (range 20-46 years). Postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractions, postoperative epithelial healing time, surgical time, postoperative pain rating and corneal haze were recorded.nnnRESULTSnAt week 1, statistically the UDVA was significantly better in the t-PRK eyes; however, at 3 months, similar refractive stability was achieved in both groups. The mean spherical equivalent (SE) decreased from -2.44±1.00D (m-PRK eyes) and -2.88±1.24D (t-PRK eyes) at baseline to -0.19±0.38D and -0.30±0.40D, respectively, after 1 year. Surgical time was 98.6±9.8s in m-PRK eyes and 58.0±6.4s in t-PRK eyes. On postoperative days 1 and 3, using the global assessment rating, 81% of mPRK eyes that had pain, reported more pain than that reported for the tPRK eyes. In addition, m-PRK treated eyes demonstrated higher mean pain scores based on the 11-point numerical rating scale and Visual Analogue Scale (VAS). The mean time to complete epithelial healing was 2.19±0.39 days (t-PRK) and 3.76±0.43 days (m-PRK).nnnCONCLUSIONnt-PRK for mild-to-moderate myopia was more comfortable than conventional m-PRK; patients had less pain, and faster healing time.

Comparison of Accelerated Corneal Collagen Cross-linking Types for Treating Keratoconus

ABSTRACT Purpose: To compare the results of different protocols for accelerated corneal collagen cross-linking (CXL) in patients with progressive keratoconus. Materials and method: This prospective comparative study involved 40 patients treated with intended UV-A radiance of 5.4 J/cm2 in 74 eyes (Group 1) and 42 patients treated with radiance of 7.2 J/cm2 in 72 eyes (Group 2). Visual acuity, subjective manifest refraction and corneal topography were analyzed before and 12 months after surgery in both groups. Postoperative complications were also noted. The results of the two protocols were statistically compared. Results: There were no statistically significant differences between the groups in uncorrected distance visual acuity, corrected distance visual acuity or corneal topography pre- or postoperatively. The differences in keratometric readings (K apex, SimK1 and SimK2) and refractive results were not significant. Conclusion: The application of total intended UV-A radiance of 5.4 J/cm2 or 7.2 J/cm2 for accelerated CXL in patients with progressive keratoconus resulted in similar refractive and topographic outcomes.

Detailed ophthalmologic evaluation of posterior microphthalmos

We performed various ophthalmic investigations in order to confirm the diagnosis and document the various features of posterior microphthalmos in a 21-year-old male. Ophthalmic examination revealed low vision with high hyperopia, papillomacular folds, midperipheral pigmentary changes and crowded optic discs. The optic discs were small and crowded with increased nerve fiber layer thickness. Fundus fluorescein angiography showed reduced diameter of a capillary free zone. Anterior segment (AS) optical coherence tomography demonstrated near normal anterior chamber depths, but markedly diminished anterior chamber angles. In spite of the increased corneal thickness and steep corneas, lens thickness and endothelial cell counts were normal. Sclerochoroidal thickening and foreshortening of the globes were detected with B-scan ultrasonography. Electroretinographic findings and visual field tests were similar to those in pigmentary retinopathy. Posterior microphthalmos is a complex eye disorder, which affects predominantly the posterior segment but also involves the AS of the eye.

Intravitreal ranibizumab for neovascular age-related macular degeneration patients with good baseline visual acuity and the predictive factors for visual outcomes

PURPOSEnTo evaluate the efficacy of intravitreal ranibizumab for the treatment of neovascular age-related macular degeneration (nAMD) patients with a visual acuity (VA) of ≥ 20/40 and to investigate the predictive factors for visual outcomes.nnnMETHODSnThe present study is a retrospective analysis of patients with VA ≥ 20/40. Injections were given monthly for the first 3 months and thereafter as needed. The patients were divided into two groups; group 1, patients not receiving further injections beyond the 3 loading doses, and group 2, those who received further injections. Next, group 2 was divided into two subgroups; group 2A, patients who did not experience VA loss, and group 2B, those who experienced VA loss. Data collected for each patient included VA and central retinal thickness (CRT) measured at baseline, months 3, 6, 9, and 12.nnnRESULTSnThe study included 96 eyes of 96 patients. Change in VA showed a significant inverse correlation with total number of injections at month 12 (r=-0.34, P=0.001), and the presence of pigment epithelial detachment (PED) at baseline (r=-0.35, P<0.01). VA outcomes were better in group 1 than group 2 at all time points (P<0.001 for all). Change in VA at month 3 was not significantly different between groups 2A and 2B (P=0.26); however, change in VA at month 6, 9, and 12 were statistically different between the two groups (P<0.001 for all).nnnCONCLUSIONnIntravitreal ranibizumab is an effective treatment for nAMD patients with good VA. The presence of PED, need for reinjection, and VA loss were unfavorable prognostic factors.

Two-Year Follow-Up of Artisan Iris-Supported Phakic Anterior Chamber Intraocular Lens for Correction of High Myopia

ABSTRACT Purpose: To evaluate the results of Artisan iris-supported phakic anterior chamber intraocular lens (pIOL) implantation in patients with high myopia. Methods: Medical records of patients who underwent Artisan pIOL implantation for surgical correction of myopia were retrospectively reviewed. Only patients with at least a two- year follow-up were included. Spherical equivalent of manifest refractive error (SE), uncorrected visual acuity (UDVA), distance corrected visual acuity (CDVA), and endothelial cell density (ECD) were analyzed at six months, one year, and two years after surgery. Results: Sixty-two eyes of 42 patients were included in the study. All patients had a minimum anterior chamber depth of 3.0u2009mm from the endothelium. At two years, 68% of the patients were within ±0.50 D. Mean ECD was 2723u2009±u2009311 cells/mm2 preoperatively and 2630u2009±u2009291 cells/mm2 at six months postoperatively (3.4% loss, pu2009=u20090.001). ECD loss from six months postoperatively to two years postoperatively was not statistically significantly different. In three eyes (4.8%) of two patients, a temporary, steroid-induced increase in intraocular pressure (IOP) was detected. Conclusion: Artisan pIOL implantation is a safe and highly effective procedure for surgical correction of high myopia. ECD loss stabilizes in the early postoperative period.

Ocular imaging findings of bilateral optic disc pit in a child

BACKGROUNDnTo report a rare condition of bilateral optic disc pit in a child.nnnCASE DESCRIPTIONnA ten-year-old female was admitted with a complaint of headache. Visual acuity was 20/20 in both eyes (OU). Anterior segment examination was normal in OU. Fundus examination revealed optic disc pit (ODP) located temporally with a diameter of 1/5 disc diameter in OU. Intraocular pressure was within normal limits in both eyes. Macular optical coherence tomography (OCT) showed a loss of retinal tissue at the site corresponding to the ODP in both eyes. Retinal nerve fiber OCT revealed decreased RNFL thickness at the temporal side of the optic nerve, corresponding to the ODP in both eyes. The patient and patients parents were informed about the disease and called for follow-up examinations every 6 months. In addition, the family was informed about optic pit maculopathy (OPM) and, they were told to return immediately if the patient ever complained of decreased vision in either of her eyes. After a follow-up period of 12 months, visual acuity remained stable, and no complications secondary to ODP were detected.nnnCONCLUSIONnOptic disc pit is diagnosed incidentally unless it is complicated with OPM. The retinal nerve fiber layer thickness is decreased at the side of the optic nerve corresponding to the ODP.

Intravitreal bevacizumab for choroidal neovascularization secondary to angioid streaks: A report of two patients.

The aim of this study is to report clinical course of choroidal neovascularization secondary to angioid streaks (AS) in two patients who underwent intravitreal bevacizumab therapy. Fundus examination, fluorescein angiography (FA) and optical coherence tomography (OCT) revealed the diagnosis of subfoveal classic choroidal neovascularization (CNV) in the right eye in patient 1 and in the left eye in patient 2. After three consecutive bevacizumab injections, visual acuity improved from 20/40 to 20/25 in patient 1 and from 20/80 to 20/50 in patient 2. After 3xa0months of therapy, additional bevacizumab injection was administered when the lesion showed recurrence. After a follow-up time of 24-months, patient 1 received 14 intravitreal bevacizumab injections; patient 2 received only 4 injections. Visual acuities remained stable at 20/32 and 20/50 in patient 1 and patient 2, respectively. Though, the patients of CNV secondary to AS showed similar clinical appearance at the beginning, this report provides the data for different responses to intravitreal bevacizumab therapy. While fewer injections were required to control the disease in one patient, the other patient needed much more injections for stabilization of the CNV. Further studies are required to understand the cause of varied treatment responses in those patients.