Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal
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Higher-order aberrations following wavefront-guided photorefractive keratectomy and laser in situ keratomileusis
Get PDFBackground: We aimed to evaluate higher-order aberrations (HOAs) following wavefront-guided photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in patients with myopia and myopic astigmatism.
Methods: This retrospective observational case-control study included patients who underwent wavefront-guided PRK (40 eyes of 20 patients) or LASIK (40 eyes of 20 patients) between August 2018 and November 2018 at the refractive surgery unit of Kayseri City Hospital Eye Clinic, Turkey. The corrected distance visual acuity (CDVA), manifest refraction, corneal topography, and HOAs were evaluated preoperatively and 3 months postoperatively in all patients.
Results: The mean age ± standard deviation (SD) was 27.13 ± 5.54 years and 29.10 ± 4.38 years in the PRK and LASIK groups, respectively (P = 0.06). Both groups had a mean CDVA of 1.00. The mean ± SD of spherical and spherical equivalent values was -2.09 ± 1.56 diopter (D) and -3.03 ± 1.72 D in the PRK group and -2.23 ± 1.69 D and -3.35 ± 1.71 D in the LASIK group, respectively (P = 0.58). When the preoperative and postoperative HOAs and root mean square (RMS) values (for a 6-mm pupil diameter) were compared in the PRK group, a significant difference was found in vertical coma and total RMS values (P = 0.003 and P less than 0.001, respectively); in the LASIK group, there was a significant difference in preoperative and postoperative vertical coma and total RMS values (P = 0.0.001 and P less than 0.001, respectively). There was no significant difference in preoperative and postoperative vertical coma values between the two groups (P = 0.735 and P = 0.583, respectively).
Conclusions: In terms of HOAs, total RMS values decreased significantly and vertical coma values increased significantly at 3 months postoperatively in both PRK and LASIK groups. However, there were no differences between the two groups
Combined implantation of toric and spherical intraocular lenses for low corneal astigmatism correction
Get PDFBackground: This study compared outcomes of combined toric versus spherical intraocular lens (IOL) implantation in patients with low corneal astigmatism.
Methods: In this retrospective contralateral study, patients with corneal astigmatism who received combined toric (FIL 611 T, Soleko, Rome, Italy) and spherical IOL (FIL 611 T, Soleko, Rome, Italy) implants were recruited. Eyes were examined preoperatively and then again 3 months postoperatively. Postoperatively, uncorrected distance visual acuity (UCDVA), residual astigmatism, and spherical equivalent (SE) were compared between the toric IOL-implanted eyes and the spherical IOL-implanted fellow eyes.
Results: Among the 46 included cases (age 69 ± 12.7 years [mean ± standard deviation]; range: 60-78 years), 86.9% of eyes (n = 40) in the toric IOL group had a postoperative refractive cylinder of less than or equal to 0.25 diopters (D), compared with 4.3% (n = 2) of eyes in the spherical IOL group. Both groups showed a statistically significant reduction in refractive cylinder and improvement in UCDVA after cataract surgery (both P = 0.01). Similarly, toric IOLs were superior (69.6%) to spherical lenses (2.2%) in obtaining a SE of less than or equal to 0.25 D.
Conclusions: To our knowledge, no previous study had sought to compare low-power toric and spherical IOLs in low corneal astigmatism in the same patient's eyes. Our findings suggest that low-power toric IOLs may result in good refractive outcomes as compared with spherical IOLs implanted in the fellow eye of the same patient, although both result in significant UCDVA improvement. Well-designed clinical research studies with a longer follow-up and more participants are necessary to confirm these findings
Progression in pediatric glaucoma: Lessons learnt from 8 years’ follow-up
Get PDFBackground: Surgical procedures are used as 1 of the main treatment modalities for pediatric glaucoma, even though progression may occur. In this study, we aimed to investigate the risk factors affecting the progression of pediatric glaucoma.
Methods: In this retrospective cohort study, we reviewed the medical records of patients diagnosed with pediatric glaucoma between April 2009 and March 2017. Pediatric glaucoma patients who underwent regular follow-up for at least 1 year were included. Demographics, intraocular pressure (IOP), central corneal thickness (CCT), axial length (AL), cup-to-disc ratio (C/D ratio), corneal diameter, type of glaucoma, age at time ofdiagnosis, and age at surgery were recorded. Progression was defined as an increase in AL > 2 mm, C/D ratio > 0.2, or corneal diameter > 1 mm during 1 year of follow-up.
Results: Eighty-three eyes from 46 patients were included: 37 eyes (45%) with primary congenital glaucoma (PCG), 46 eyes (55%) with secondary glaucoma, and 27 of these 83 eyes (32.5%) showed progression. Progression was comparable between eyes with PCG and secondary glaucoma (PCG, 22%; secondary glaucoma, 41%; P = 0.152). Age at the time of diagnosis and age at the time of the first surgery were significantly lower in the eyes with progression (P = 0.046 and 0.012, respectively). The mean ± standard deviation of surgeries in progressed versus non-progressed eyes was 1.88 ± 1.1 versus 1 ± 0.8 (P = 0.015). The frequency of comorbid systemic disease was significantly higher in patients with glaucoma progression (P = 0.043). The progressed and non-progressed eyes were comparable in terms of other demographic characteristics and ocular parameters (all P > 0.05).
Conclusions: Pediatric glaucoma patients who were younger at the time of diagnosis and the first glaucoma surgery and those with comorbid systemic disease are at higher risk of glaucoma progression. These findings are useful for clinicians when counseling parents of children with pediatric glaucoma about disease outcomes. However, future prospective studies with larger sample sizes and longer follow-up periods are needed to confirm our findings
Comparison of optical coherence tomography angiography features in type 1 versus type 2 choroidal neovascular membranes secondary to age-related macular degeneration
Get PDFBackground: Optical coherence tomography angiography (OCTA) is an advanced imaging modality that provides high resolution images at the level of different retinal layers. This study aime to evaluate choroidal neovascular membranes (CNVMs) secondary to age-related macular degeneration (AMD) quantitatively and qualitatively, according to their classification, morphological features, and flow areas, using OCTA.
Methods: In this descriptive, comparative, cross-sectional study, CNVMs were divided into 2 groups according to their classification as type 1 or type 2 neovascularization. Mixed CNVMs were excluded from the study. The size (mm2) and the flow area (mm2) of the CNVMs were calculated via OCTA and the presence of the perivascular halo and loop anastomoses were analyzed. The morphological appearance of the CNVMs were classified as: medusa, sea-fan, lacy-wheel, glomerular, dead tree, and mature vascular networks.
Results: Of the 85 eyes assessed for eligibility, 45 eyes of 34 individuals with CNVM were enrolled in this retrospective study. Twenty-eight eyes had type 1 and 17 eyes had type 2 CNVMs. The mean size and flow area were greater in type 1 than in type 2 CNVMs (mean ± standard deviation [SD], 6.69 ± 4.54 and 3.61 ± 3.56 mm2 versus 3.04 ± 1.98 and 1.77 ± 1.62 mm2; P = 0.044 and 0.046, respectively). Among the 22 eyes with type 1 CNVMs and the 9 eyes with type 2 CNVMs, 31 eyes had exudative membranes. Among the eyes with exudative CNVMs, 22 eyes had a perivascular halo and 22 eyes had loop anastomoses; this was significantly more than in the non-exudative eyes (P = 0.042 and 0.041, respectively). The lacy-wheel (38.7%) and dead tree (71.4%) patterns were the most frequent morphological appearance of the CNVMs in the exudative and non-exudative membranes, respectively.
Conclusions: OCTA provides objective documantation about CNVMs. A perivascular dark halo around CNVMs could be a criterion to define exudative membranes activity
Preservative-free versus preserved latanoprost eye drops for reducing intraocular pressure: a non-inferiority phase III randomized, multi-center, single-blind, parallel-group controlled trial
Get PDFBackground: The aim of this study was to test the non-inferiority of preservative-free (PF) latanoprost 50 micrograms per milliliter multi-dose ophthalmic solution versus the marketed benzalkonium chloride (BAK)-preserved latanoprost 50 micrograms per milliliter ophthalmic solution in patients with open-angle glaucoma and patients with ocular hypertension.
Methods: This was a prospective, national, randomized, multi-center, observer-blind, parallel-group controlled clinical trial. Patients were randomized to receive either PF or BAK-preserved latanoprost once daily for 12 weeks. The primary endpoint was the change in intraocular pressure (IOP) at 8:00 AM in the affected eye between the end of the treatment (week 12) and the baseline (week 0). Secondary measurements were taken at weeks 2 and 6, with IOP being recorded at 8:00 AM, 12:00 PM, and 4:00 PM.
Results: A total of 158 patients were included in the per protocol (PP) population (77 in the PF latanoprost treatment arm and 81 patients in the BAK-preserved latanoprost treatment arm). PF latanoprost was non-inferior to BAK-preserved latanoprost in reducing IOP at 8:00 AM in the study eye from the baseline (week 0) to the end of the treatment (week 12). The point estimate of the between-treatment difference was 0.1 mmHg (95% confidence interval: -0.646, 0.847). Mean between-group differences in IOP reduction from the baseline to each of the secondary measurements were also similar between the two treatment arms. The two treatments were well tolerated and had comparable adverse event profiles.
Conclusions: PF latanoprost was non-inferior to BAK-preserved latanoprost in reducing IOP in patients with open-angle glaucoma or ocular hypertension. Both treatments were well tolerated
Sutureless scleral-fixated intraocular lens: long-term outcomes
Get PDFBackground: The purpose of this study was to evaluate the long-term outcomes of sutureless scleral-fixated intraocular lens (SFIOL) implantation at a tertiary referral center.
Methods: This retrospective observational study included 50 eyes of 43 consecutive patients who underwent sutureless SFIOL implantation by a single surgeon from January 2009 to December 2015. Indications for surgery were aphakia, dislocated intraocular lens (IOL), complicated cataract surgery (posterior capsule rupture, zonular dialysis, dropped nucleus), iris-clipped IOL with corneal decompensation, and lens with poor capsular support. Indication for surgery, visual acuity, ocular history, ocular comorbidities, intraoperative and postoperative complications, and the need for further surgery were analyzed.
Results: The analysis conducted on 50 eyes from 43 patients with a mean ± standard deviation (SD) follow-up of 16.64 ± 9.34 months. Patients were 27 (63%) men and 16 (37%) women with a mean ± standard deviation (SD) age of 53.36 ± 22.45 years (range 8-90 years). Final visual acuity was 6/18 or better in 39 eyes. SFIOL was stable and well centered in 48 eyes. SFIOL dislocation was noted in 2 eyes, retinal detachment in 1 eye, and worsening of diabetic cystoid macular edema in 1 eye. Two patients with pre-existing corneal decompensation from complicated cataract surgery had worsening of their condition
Conclusions: Sutureless SFIOL could be considered as a long-term option for the management of aphakia, dislocated IOL, and lens with poor capsular support. However, future studies with more subjects, longer follow-ups, and robust study design are needed to confirm the results of the present study
Changes in anterior segment parameters of normal subjects during accommodation using a Scheimpflug imaging system
Get PDFBackground: Accommodation changes ocular parameters, such as the anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle (ACA), and pupil diameter (PD), which can reflect a risk of angle-closure glaucoma. Previous studies of changes in ocular anterior segment parameters, have used high diopters or maximum amplitude. Here, we focused on normal accommodation at a reading distance of 30-40 cm. The aim of this study was to assess changes in anterior segment parameters during a normal accommodative state, using a Scheimpflug imaging system.
Methods: In this cross-sectional study, 40 emmetrope subjects (mean ± SD of age: 22 ± 4.0 years) who met the inclusion criteria and provided informed consent were enrolled. Clinical history, refraction, amplitude of accommodation, slit lamp examination, Goldman applanation tonometry, and Pentacam investigations were performed on all subjects. Accommodative and non-accommodative targets were induced via the Pentacam. Two seconds were allowed for accommodation or relaxation prior to measurements in each eye.
Results: Eighty normal eyes were evaluated; a small but statistically significant change in ACV, ACA, and PD during accommodation (P < 0.01, < 0.01, and < 0.05, respectively) was observed. The ACD did not change substantially with accommodation (P = 0.29). The mean ± SD values of ACV, ACD, ACA, and PD before and after accommodation were 151.85 ± 24.04 mm3 and 145.38 ± 23.30 mm3, 2.87 ± 0.28 mm and 2.86 ± 0.27 mm, 35.06° ± 3.68° and 33.84° ± 3.72, and 3.46± 0.57 mm and 3.41 ± 0.53 mm, respectively.
Conclusions: Accommodation changes ocular parameters, such as ACV, ACA, and PD, in healthy young emmetropes. Interestingly, the ACD remains unaltered during accommodation. Nevertheless, although these changes were statistically significant, they were not clinically significant in our study
Acquired symptomatic external punctal stenosis: A tertiary referral center study
Get PDFBackground: To report the prevalence of acquired symptomatic external punctal stenosis (EPS) in a tertiary referral center in Kuwait, and to study the associated risk factors, etiologies, and management outcomes.
Methods: This prospective interventional hospital-based study was performed at the Farwaniya governmental hospital in Kuwait between November 2018 and November 2019. All patients were referred to the oculoplastic clinic with symptomatic epiphora, age > 18 years, epiphora Munk score equal or more than 0, tear film meniscus equal or more than 2 mm, and punctum with a grade equal or less than 2 (smaller than normal size, but recognizable) were included. Exclusion criteria were congenital causes of epiphora, previous eyelid surgeries, and traumatic or neoplastic causes of punctal or canalicular obstruction.
Results: A total of 418 patients with symptomatic epiphora, who were referred to our oculoplastic clinic, were enrolled in our study. The prevalence of EPS was 70.3%. Examination of the puncta revealed different shapes, including tangential, pinpoint, elevated, slit-shaped, horse shoe-shaped, and membranous puncta, with the tangential type accounting for the greatest proportion (65.3%). Bilateral punctal stenosis was observed in 206 patients (70.1%) and unilateral involvement in 88 patients (29.9%). Dilatation and syringing were performed for all puncta upon diagnosis, and repeated dilatation was performed for 225 puncta (32.7%). Placement of a Mini-Monoka tube was performed in 11 puncta (1.6%).
Conclusion: EPS was a common cause of symptomatic epiphora in our study. Aging and female sex were identified as common risk factors. Most etiological factors of EPS were associated with a pathophysiological inflammatory mechanism. For exact estimates of its prevalence, a population-based study is necessary in future
Biometric changes after vitrectomy with silicone oil tamponade
Get PDFBackground: The Lenstar LS 900 (Haag-Streit AG, Koeniz, Switzerland) is an optical biometer, and its measurements are highly repeatable and precise in cataractous eyes. This study investigated changes in biometric parameters, including axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous cavity depth (VD), and central corneal thickness (CCT) before and after three-port 23-Gauge pars plana vitrectomy with silicone oil tamponade.
Methods: This was a prospective follow-up study. Patients who were scheduled for surgery underwent a detailed slit-lamp examination and objective cycloplegic refraction preoperatively. In eligible cases, the Lenstar LS 900 was used to measure biometric parameters. At the 1-month postoperative follow-up, we repeated the same assessments for the silicone oil (SO)-filled eyes. Data were analyzed to assess the significance of changes and to test the possible correlation of values between the two time points.
Results: Twenty-three patients with a mean ± SD age of 60 ± 12 years completed the study. Postoperatively, we found a significant increase in AL and a decrease in ACD and CCT (all P < 0.05), with no significant changes in LT and VD. A significant correlation was found for ACD, CCT, and cylinder values between the two time points (all P < 0.05). Postoperatively, the spherical and cylindrical components of refraction demonstrated a hyperopic shift, but did not change statistically significantly.
Conclusions: The Lenstar LS 900 underestimated the ACD and overestimated the AL in SO-filled eyes when comparing pre- and postoperative values, in phakic as well as pseudophakic eyes. In planning for cataract surgery in this group of patients, it is more reasonable to calculate IOL power based on the biometric data of the fellow eye, although this may not eliminate possible errors. Further studies with a larger sample size, longer follow-up, and robust study design are necessary to confirm our preliminary results
Comparison of visual aids for improving reading performance in children with dyslexia
Get PDFBackground: Dyslexia is a key learning disorder associated with reading difficulties in children. The purpose of this study was to determine the effectiveness of simple visual devices in improving the reading performance of children with dyslexia.
Methods: A case control study was conducted by selecting 80 school children with dyslexia, aged 8 to 11 years, from the Special Dyslexic School Program of the Ministry of Education (MOE) Malaysia. Subjects were randomly assigned to four groups: the typoscope, magnifier, visual tracking magnifier (VTM), and control groups. Reading performance was measured based on reading speed and reading error rate. The time taken to complete reading of text was measured, and reading errors were recorded. The reading performance of each group was assessed at baseline, week 2, week 6, and week 12.
Results: Reading performance was significantly different (P < 0.05) for both Level 1 and Level 2, before and after intervention only in children with dyslexia using magnifiers and VTM. Reading performance for children with dyslexia using a magnifier or a VTM increased significantly (P < 0.05) from baseline to week 2, week 6, and week 12. The improvement in reading speed was 2.5 times faster for children in the VTM group than in the other groups.
Conclusions: Simple visual aids, such as a VTM and magnifying glass, improved reading performance in children with dyslexia. The VTM intervention yielded the greatest improvement after 12 weeks of intervention. Hence, it is suggested that a VTM be used as part of a rehabilitation program for all children with dyslexia in Malaysia, particularly those in dyslexia programs in schools under the MOE Malaysia. However, future studies with longer follow-up periods are needed to confirm the sustainability of this improved reading performance after discontinuation of the intervention