VOLUME 83 - ISSUE 4

Purpose: To evaluate the influence of ocular axial length on circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in healthy eyes after correcting for ocular magnification effect.
Methods: In this cross-sectional study, we evaluated 120 eyes from 60 volunteer participants (myopes, emmetropes, and hyperopes). The thickness of the circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer were measured using the spectral optical coherence tomography (OCT)-Cirrus HD-OCT and correlated with ocular axial length. Adjustment for ocular magnification was performed by applying Littmann’s formula.
Results: Before the adjustment for ocular magnification, age-adjusted mixed models analysis demonstrated a significant negative correlation between axial length and average circumpapillary retinal nerve fiber layer thickness (r=-0.43, p<0.001), inferior circumpapillary retinal nerve fiber layer thickness (r=-0.46, p<0.001), superior circumpapillary retinal nerve fiber layer thickness (r=-0.31, p<0.05), nasal circumpapillary retinal nerve fiber layer thickness (r=-0.35, p<0.001), and average ganglion cell-inner plexiform layer thickness (r=-0.35, p<0.05). However, after correcting for magnification effect, the results were considerably different, revealing only a positive correlation between axial length and temporal retinal nerve fiber layer thickness (r=0.42, p<0.001). Additionally, we demonstrated a positive correlation between axial length and average ganglion cell-inner plexiform layer thickness (r=0.48, p<0.001). All other correlations were not found to be statistically significant.
Conclusions: Before adjustment for ocular magnification, axial length was negatively correlated with circumpapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness measured by Cirrus-OCT. We attributed this effect to ocular magnification associated with greater axial lengths, which was corrected with the Littman’s formula. Further studies are required to investigate the impact of ocular magnification correction on the diagnostic accuracy of Cirrus-OCT.

Keywords: Tomography, optical coherence; Retinal ganglion cells; Axial length, eye

Purpose: This study was performed to evaluate the outcomes of accelerated corneal cross-linking in keratoconic
corneas with thinnest pachymetry values of <400 μm.
Methods: The study included 28 eyes of 24 patients. The uncorrected and best-corrected visual acuities (logMAR), flattest and steepest keratometric readings, central corneal thickness at the thinnest point, corneal higher-order aberrations, and contrast sensitivity were assessed before and at 1, 3, 6, 12, and 24 months after corneal cross-linking.
Result: The mean best-corrected visual acuity and contrast sensitivity increased (p=0.02, p=0.03, respectively), whereas the mean uncorrected visual acuity did not significantly differ (p>0.05) at 24 months after corneal cross-linking, compared with measurements before corneal cross-linking. Although the mean flattest keratometric reading showed no significant change (p=0.58), the mean steepest keratometric reading was reduced when compared with its value before corneal cross-linking (p=0.001). No change was observed in the mean central corneal thickness at the thinnest point at 24 months after corneal cross-linking, compared with its value before corneal cross-linking (p=0.12).
Conclusion: Accelerated corneal cross-linking in keratoconic eyes with thin corneas could halt the progression of keratoconus in corneas thinner than 400 μm at 24 months after treatment.

Keywords: Keratoconus; Corneal pachymetry; Cross-linking reagents; Riboflavin/therapeutic use

Purpose: To compare changes in anterior segment parameters following ExPRESS Mini Glaucoma Shunt surgery vs. trabeculectomy using the Pentacam rotating Scheimpflug camera.
Methods: In this prospective, comparative study, 27 patients with glaucoma treated at the Rabin Medical Center from 2009 to 2013 were enrolled in this prospective comparative study: 19 participants (19 eyes) underwent ExPRESS shunt implantation and 12 (13 eyes) underwent trabeculectomy. Changes in anterior chamber parameters at postoperative day 1 and postoperative month 3 were evaluated on Scheimpflug images.
Results: Intraocular pressure decreased significantly from baseline in both groups. The decrease in both groups was similar at postoperative month 3 (p=0.82). ExPRESS surgery caused a transient increase in posterior corneal astigmatism (p=0.008) and a transient decrease in anterior chamber depth (p=0.016) and volume (p=0.006) on postoperative day 1. At postoperative month 3, these parameters were no longer statistically significant (p=0.65, p=0.51, and p=0.57 respectively). Trabeculectomy caused a transient increase in anterior and posterior corneal astigmatism on postoperative day 1 (p=0.003 and p=0.005, respectively), which were not evident at postoperative month 3 (p=1.0 and p=1.0, respectively). At postoperative month 3, both ExPRESS and trabeculectomy showed similar changes in anterior chamber parameters.
Conclusions: Both ExPRESS mini glaucoma implant and trabeculectomy significantly decreased intraocular pressure and had transient effects on anterior segment parameters, with minor differences between the methods.

Keywords: Glaucoma/surgery; Glaucoma drainage implants; Trabeculectomy/methods; Intraocular pressure

Purpose: Pharmacological pupillary dilation is performed in comprehensive ophthalmological examinations and before biometric measurements. So far, there is no consensus regarding its impact on biometric measurements. This study’s aim was to investigate the effects of pharmacological pupillary dilation on ocular biometric measurements in healthy children.
Methods: This was a prospective, observational, non-randomized study of children (4-18 years of age) who were admitted for routine ophthalmological examination. Biometric measurements were performed, using a non-contact optical biometry device, both before and after pharmacological pupillary dilation with cyclopentolate hydrochloride. Intraocular lens power calculations were performed using Hill-RBF, Barrett, Olsen, Sanders-Retzlaff-Kraff/Theoretical, Holladay, and Hoffer Q formulas. Descriptive statistical analyses were also performed. The Wilcoxon signed-rank test was used to compare measurements before and after pharmacological pupillary dilation. Relationships between variables were analyzed using the Spearman-Brown rank correlation coefficient.
Results: The study included 116 eyes of 58 children (mean age, 8.4 ± 0.32 years; 34 girls). Significant changes were observed after pupillary dilation, compared with before pupillary dilation, in terms of anterior chamber depth, aqueous depth, and central corneal and lens thicknesses. No significant change was observed in axial length. Intraocular lens power calculations revealed no significant changes after pupillary dilation in most formulas except for the Olsen formula. The intraocular lens power was significantly inversely correlated with axial length and anterior chamber depth.
Conclusions: Pharmacological pupillary dilation in children appeared to have no impact on axial length and intraocular lens power, but caused a significant increase in anterior chamber depth. The difference in anterior chamber depth measurements before and after pupillary dilation could be related to the optical biometry device model used. These outcomes should be considered in intraocular lens power calculations performed using anterior chamber depth parameters.

Keywords: Dilation; Corneal pachymetry; Lenses, intraocular; Anterior chamber; Children

Purpose: To assess the microsurgery dexterity outcomes of two sequential training evaluations using virtual reality technology.
Methods: This was a multicenter cross-sectional study of all candidates who were accepted as first-year residents at one of six ophthalmology teaching institutions. Residents were subjected to two identical series of standardized, reproducible dexterity tests using virtual reality equipment (Eyesi^®): “sequence 1” and “sequence 2.” Each sequence consisted of five difficulty levels that were assessed using a proprietary scoring system. The data were tested for normality using the Shapiro-Wilk test. The differences between tests in sequences 1 and 2 were evaluated using the Wilcoxon signed-rank test.
Results: The data did not follow a normal distribution. There were improvements from sequence 1 in all the tests (all p values<0.05). The sum of all scores (total score) improved from sequence 1 (median= 152.50) to sequence 2 (median 256.00; p<0.001). There was no correlation between the delta sequence values and the average scores.
Conclusion: Two sequential training evaluations using virtual reality technology showed relevant improvement in quantifications of microsurgery dexterity. This information should be considered if virtual reality approaches are used for testing purposes, as previous experience may lead to improved test results.

Keywords: Motor skills; Virtual reality; Clinical competence; Ophthalmologic surgical procedures/education

Purpose: To investigate the usefulness of systemic inflammatory markers [i.e., white blood cell and platelet counts, mean platelet volume, and their ratios] as diagnostic markers of the pathogenesis of diabetic macular edema.
Methods: The study cohort included 80 diabetic macular edema patients (40 with diabetic retinopathy and 40 without) and 40 healthy age- and sex-matched controls. Neutrophil, lymphocyte, monocyte, and platelet counts, and the mean platelet volume were determined from peripheral blood samples, and the monocyte/lymphocyte, platelet/lymphocyte, and mean platelet volume/lymphocyte, and neutrophil/lymphocyte ratios were calculated and compared among groups.
Results: The mean neutrophil/lymphocyte ratio of the diabetic macular edema and non-diabetic macular edema groups was higher than that of the control group, and the value of the diabetic macular edema group was higher than that of the non-diabetic macular edema group (p<0.001 in diabetic macular edema vs. control, p=0.04 in non-diabetic macular edema vs. control, and p=0.03 in diabetic macular edema vs. non-diabetic macular edema). A neutrophil/lymphocyte cutoff value of ≥2.26 was identified as an indicator of the pathogenesis of diabetic macular edema with a sensitivity of 85% and specificity of 74%. The mean platelet volume of the diabetic macular edema group was higher than those of the non-diabetic macular edema and control groups, while those of the non-diabetic macular edema and control groups were similar (diabetic macular edema vs. non-diabetic macular edema, p=0.08; diabetic macular edema vs. control, p=0.02; and non- diabetic macular edema vs. control, p=0.78). All other parameters were similar between groups (all p>0.05).
Conclusion: The neutrophil/lymphocyte ratio and mean platelet volume of the diabetic macular edema group were higher than those of the non-diabetic macular edema and control groups. A neutrophil/lymphocyte ratio cutoff value of ≥ 2.26 was identified as an indicator of the pathogenesis of diabetic macular edema with high sensitivity and specificity. Moreover, the neutrophil/ lymphocyte ratio of the non-diabetic macular edema group was higher than that of the control group.

Keywords: Macular edema; Diabetic retinopathy; Mean platelet volume; Lymphocyte count; Neutrophils; Inflammation

Purpose: Collagen deposition and myofibroblast differentiation are critical factors related to excessive scarring in ocular surgeries. This study evaluated the anti-fibrotic activity of rosmarinic acid on rabbit Tenon’s capsule fibroblasts stimulated with transforming growth factor-β2.
Methods: Primary cultures of rabbit Tenon’s capsule fibroblasts were treated with various concentrations of rosmarinic acid for 12 h, in the presence and absence of transforming growth factor-β2. After 48 h, the proliferation index of rabbit Tenon’s capsule fibroblasts and the differentiation of myofibroblasts were investigated through immunofluorescence staining for proliferating cell nuclear antigen and alpha smooth muscle actin. An automated cell counter and colorimetric metabolic activity assay were used to evaluate cell number and viability. Collagen expression and production were determined by quantitative real-time polymerase chain reaction and hydroxyproline assay, respectively.
Results: Unstimulated rabbit Tenon’s capsule fibroblasts treated with any concentration of rosmarinic acid exhibited diminished collagen expression (p<0.01) but showed no differences in proliferation index. Transforming growth factor-β2 exposure induced myofibroblast differentiation and increased collagen production. Exposure to rosmarinic acid at 1.0 and 3.0 µM concentrations reduced the proliferation index (p<0.02), as well as the collagen expression and hydroxyproline content (p<0.05). Exposure to 3.0 µM rosmarinic acid reduced viability (p=0.035) in unstimulated rabbit Tenon’s capsule fibroblasts and cell numbers (p=0.001) in both stimulated and unstimulated rabbit Tenon’s capsule fibroblast cultures.
Conclusions: Exposure to 1.0 µM rosmarinic acid was noncytotoxic and led to reduced collagen expression and proliferation of stimulated rabbit Tenon’s capsule fibroblasts. These findings suggest that rosmarinic acid is a relatively non-injurious anti-fibrotic compound to rabbit Tenon’s capsule fibroblasts, with potential application as an adjunctive agent in ocular procedures, particularly in glaucoma surgeries.

Keywords: Glaucoma; Ophthalmologic surgical procedures; Fibroblasts; Healing; Rosmarinic acid

Purpose: To analyze the clinical outcomes of the ocular surface in patients with vitamin D deficiency after oral replacement.
Methods: A total of 40 patients with vitamin D deficiency were enrolled in the study. The patients received 50,000 units of oral vitamin D weekly over a period of 8 weeks. After 8 weeks, 1,500-2,000 units/d were administered for 24 weeks. Eyelid margin score, meibomian gland expressibility score, Oxford grading, Schirmer I test, tear breakup time, tear osmolarity, and the Ocular Surface Disease Index score were evaluated at baseline, and at 8, 12, and 24 weeks.
Results: The meibomian gland expressibility score, Schirmer I, tear breakup time, tear osmolarity, and Ocular Surface Disease Index score showed improvement 8 weeks after vitamin D supplementation (p<0.05). Compared with the pretreatment values, the eyelid margin score and Oxford grading were decreased at week 12 (p<0.05).
Conclusion: Vitamin D replacement appears to improve ocular surface in individuals with vitamin D deficiency.

Keywords: Dry eye syndrome; Vitamin D deficiency; Dietary supplements

Purpose: The renin-angiotensin system is involved in the pathogenesis of retinal ischemic conditions and glaucoma. Our objective was to evaluate the renin, angiotensinconverting enzyme 1, and angiotensin-converting enzyme 2 activities in aqueous humor and blood samples of patients with and without primary open-angle glaucoma.
Methods: We analyzed samples from 56 participants who underwent ocular surgeries. The patients were divided into two groups: patients with cataract alone (n=28) and patients with cataract and primary open-angle glaucoma (n=28). Venous blood (2 ml) and aqueous humor (150 µl, via paracentesis) samples were collected during phacoemulsification (cataract only) or glaucoma surgery (cataract and primary open-angle glaucoma). The serum and aqueous humor renin, angiotensin-converting enzyme 1, and angiotensin-converting enzyme 2 activities of all patients were evaluated by fluorimetric assays, and results were analyzed by using multivariate regression analysis.
Results: Both the aqueous humor renin activity and renin activity aqueous humor/serum ratio were significantly lower in patients with cataract and primary open-angle glaucoma than in patients with cataract only [(mean ± SE): 0.018 ± 0.006 ng/ml/h vs 0.045 ± 0.009 ng/ml/h, p<0.001; 0.05 ± 0.02 vs 0.13 ± 0.05, p=0.025]. Multivariate analyses showed a significant relationship between lower aqueous humor renin activity and primary open-angle glaucoma [coefficient (±SE): -0.029 ± 0.013, p=0.026].
Conclusions: Our results showed that patients with primary open-angle glaucoma had lower aqueous humor renin activity. As timolol eye drops were used by most of the primary open-angle glaucoma patients, we propose that a large sample of washed-out patients should be studied in the future to discriminate the involvement of b-blocker treatment in the aqueous humor renin activity.

Keywords: Glaucoma, open-angle; Cataract; Aqueous humor; Renin-angiotensin system

Purpose: To determine the frequency of ocular squamous surface neoplasia associated with pterygium in an ophthalmology reference center in Central Mexico.
Methods: We reviewed histopathological reports and slides of all patients who underwent pterygium surgery from 2014 to 2016 at the Instituto Mexicano de Oftalmologia in Queretaro (Mexico).
Results: We studied 177 biopsy samples; 66% were from women, and the median age was 52 years. We found ocular squamous surface neoplasias in 11.29% (n=20) of the samples. One biopsy sample revealed a poorly differentiated keratinizing and infiltrating carcinoma.
Conclusions: The prevalence of ocular squamous surface neoplasia in our region appears to be high. Countrywide studies are necessary to determine the true prevalence of ocular squamous surface neoplasia in Mexico and to examine related risk factors.

Keywords: Pterygium; Conjunctival neoplasms; Eye neoplasms; Histopathology; Carcinoma, squamous cell

Despite the recent developments in modern cataract surgery and the application of a vast array of new devices and machines, late in-the-bag intraocular lens dislocation remains a devastating, albeit rare, complication. Various nonsurgical and surgical techniques have been used to manage this complication. We report a case of spontaneous repositioning in the left eye of an anteriorly subluxated in-the-bag intraocular lens. The spontaneous repositioning may have been caused by antagonistic effects related to the topical administration of brimonidine and prednisolone. The dislocation was treated without aggressive manipulation or surgical intervention.

Keywords: Mydriasis; Miosis; Lenses, intraocular; Lens subluxation/ chemically induced; Lens subluxation/surgery; Postoperative complications

Dacryocystocele is a rare benign facial abnormality of the nasolacrimal system, which may be detected at the antenatal workup during the third trimester of pregnancy. Ultrasound is the method of choice for this examination. However, magnetic resonance imaging may also be used in selected cases. Dacryocystocele is mostly a transient finding; it may resolve spontaneously in utero or postnatally. When the defect is bilateral and persists in neonatal life, it may lead to respiratory complications. We report a case of a fetus with bilateral dacryocystocele diagnosed by prenatal ultrasound at the beginning of the third trimester of pregnancy with spontaneous postpartum resorption.

Keywords: Dacryocystitis/congenital; Dacryocystitis/diagnostic imaging; Lacrimal duct obstruction/congenital; Lacrimal duct obstruction/diagnostic imaging; Ultrasonography, prenatal

Perfluorocarbon liquid has been widely used during vitreoretinal operations. Subretinal retention is a rare intraoperative complication, but even small quantities can damage the macular structure and function, and no standard treatment has been established. We encountered a 43-year-old woman who presented a retained subfoveal bubble after a vitreoretinal operation due to primary rhegmatogenous retinal detachment. Herein, we describe the procedure we used to remove the perfluorocarbon liquid without retinotomy using internal limiting membrane peeling.

Keywords: Retinal detachments; Vitrectomy; Vitreoretinal surgery; Fluorocarbons; Intraoperative complications; Tomography, optical coherence

Infantile hemangioma, the most common benign tumor in infancy, is usually an isolated condition occurring in many different locations in the body. However, large infantile hemangioma may be associated with other systemic malformations, including central nervous system, cerebrovascular, cardiac, and ophthalmology abnormalities, a condition termed PHACE syndrome. In this paper, we describe a case of PHACE syndrome that was presented with the unique association of a large facial infantile hemangioma and morning glory anomaly.

Keywords: Hemangioma; Eye abnormalities; Aortic coarctation; Neurocutaneous syndrome; Magnetic resonance imaging; Humans; Case reports

The approach to any refractive condition of the eye with regular astigmatism is more complicated than that for myopia or hyperopia alone. It requires familiarity with the complex images collectively identified as Sturm’s conoid. Fortunately, only three of those play a critical role in the interpretation of ametropia with astigmatism. This manuscript discusses a prescription strategy for ametropias associated with regular astigmatism evolved from those three key images.

Keywords: Astigmatism; Refractive errors