Sergio Petroni

Unilateral amblyopia: An optical coherence tomography study

PURPOSE To determine whether retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and foveal volume (FV) in patients with unilateral amblyopia differ between the amblyopic and the sound eye. METHODS A Humphrey-Zeiss Stratus (OCT3) with software 4.0.3.1 was used to evaluate 40 patients (17 male, 23 female; mean age, 15.2 years; range, 5-56 years) with unilateral amblyopia. Patients were divided into 2 groups: 20 strabismic and 20 anisometropic. Maps of macular thickness and RNFL thickness (3.46) created by the use of optical coherence tomography were applied to calculate FV and MT and RNFLT. RESULTS Mean best-corrected visual acuity was +0.3 LogMAR (range, +0.2 to +1.0) in the amblyopic eye. Mean RNFL thickness was not significantly different between eyes in either group. In strabismic amblyopia, mean MT and FV were 5% lower in the sound eye than in the amblyopic eye (MT, 267 microm vs 253 microm, p = 0.005; FV, 2.57 mm(3) vs 2.43 mm(3), p = 0.001). In anisometropic amblyopia, there was no significant difference between eyes in either MT or FV. CONCLUSIONS In patients with strabismic amblyopia, the MT and FV were slightly but significantly lower in the sound eye than in the amblyopic eye. The clinical importance of this difference is not known. No such difference was observed in patients with anisometropic amblyopia.

Iontophoretic transepithelial corneal cross-linking to halt keratoconus in pediatric cases: 15-month follow-up.

Purpose: To report the results 15 months after transepithelial corneal cross-linking by iontophoresis of riboflavin performed in pediatric patients affected by keratoconus. Methods: Fourteen eyes of 14 pediatric patients [mean age 13 ± 2.4 (SD) years; range, 10–18 years] were treated. Riboflavin solution was administered by iontophoresis for 5 minutes, and then UVA irradiation (10 mW/cm2) was performed for 9 minutes. The corrected distance visual acuity measured as decimal number, spherical equivalent, refractive astigmatism, simulated K, corneal coma, spherical aberration, and high-order aberrations for 5.0-mm pupil and the thinnest point were measured preoperatively and 3, 6, 12, and 15 months postoperatively. The endothelial cell density was evaluated. The paired Student t test was used to compare data during the follow-up. Results: Fifteen months after the procedure, the corrected distance visual acuity improved from 0.7 ± 1.7 to 0.8 ± 1.8 (P = 0.005). Spherical equivalent and refractive astigmatism as well as topographic and aberrometric data did not show significant changes. Also, the mean thinnest point and the endothelial cell density remained unchanged. The optical coherence tomography showed a nonhomogeneous but deep hyperreflective band with a fading effect extending through the anterior 180 &mgr;m of the cornea. No side effects were recorded. Conclusions: Transepithelial collagen cross-linking by iontophoresis, unlike other transepithelial techniques, seems to halt pediatric keratoconus progression over 15 months. However, we did not record significant improvement in higher-order aberrations and topographic indices.

A morpho-functional study of amblyopic eyes with the use of optical coherence tomography and microperimetry.

PURPOSE To determine whether retinal nerve fiber layer thickness (RNFLT), macular thickness, foveal volume, macular sensitivity, and fixation in patients with amblyopia differ between the amblyopic eye and the fellow eye. METHODS Optical coherence tomography (OCT) and microperimetry (MP-1) were used to evaluate patients with unilateral amblyopia. Patients were divided into 2 groups, those with strabismic amblyopia and those with refractive amblyopia. OCT maps were used to calculate foveal volume, macular thickness, and RNFLT; MP-1 was used to determine macular sensitivity and fixation. RESULTS A total of 30 patients were included (13 males; mean age 19.7 years [range, 10-38 years]), 15 in each group. Mean best-corrected visual acuity was 20/35 (range, 20/50 to 20/32) in the amblyopic eye and 20/21 (range, 20/20 to 20/25) in the fellow eye. In both groups, mean foveal volume and RNFLT did not differ significantly between eyes. Only macular thickness in the strabismic group differed significantly between the amblyopic and fellow eyes (P = 0.03). Macular sensitivity was significantly greater in the fellow eye in both groups (strabismic group, P = 0.002; refractive group, P = 0.013), whereas fixation did not change significantly between the amblyopic and fellow eye. RNFLT and macular sensitivity was found to be significantly correlated (strabismic group, r = 0.84, P = 0.002; refractive group, r = 0.66, P = 0.02). CONCLUSIONS Our data suggest that although RNFLT does not vary between eyes, macular sensitivity is reduced in patients with amblyopia.

Laser welding in penetrating keratoplasty and cataract surgery in pediatric patients: Early results

Purpose To evaluate the efficacy of diode laser welding to close corneal wounds in penetrating keratoplasty (PKP) and cataract surgery in pediatric patients. Setting Ophthalmology Department, Bambino Gesù Children’s Hospital, Rome, Italy. Design Prospective observational study. Methods Patients had surgery for congenital cataract (Group 1) or femtosecond laser–assisted PKP (Group 2). The surgery was followed by corneal wound closure using diode laser welding of the stroma. In Group 1, no standard suturing was used. In Group 2, the donor button was sutured onto the recipient using 8 single nylon sutures or a 10‐0 nylon running suture (12 passages). Laser welding was then used as an adjunct to the traditional suturing procedure. Results Group 1 comprised 7 eyes (7 patients; mean age 8.1 years ± 5.3 [SD], range 1 to 15 years) and Group 2, 5 eyes (5 patients; mean age 10.6 ± 3.3 years, range 6 to 15 years). The adhesion of the laser‐welded tissues was perfect; there were no collateral effects, and restoration of the treated tissues was optimum. Seidel testing showed no wound leakage during the follow‐up. Postoperative astigmatism did not change significantly from the first day after cataract surgery and shifted moderately 3 months after PKP. Conclusion Laser welding of corneal tissue appeared to be safe and effective in children for whom a sutureless surgical procedure is important to reduce the use of anesthesia for suture management, prevent endophthalmitis, and improve the antiamblyopic effect. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Measurement of retinal nerve fiber layer thickness, macular thickness, and foveal volume in amblyopic eyes using spectral-domain optical coherence tomography

Although the changes in the anatomy of the visual cortex and lateral geniculate nucleus as the result of amblyopia have been well documented, retinal involvement is still controversial. Time-domain optical coherence tomography with an axial resolution of 10 μm has been used to evaluate retinal and peripapillary tissues in amblyopic eyes with contradictory results. Spectral domain optical coherence tomography has a greater resolution (5-10 μm) and can determine retinal layers more precisely. Our purpose was assess by means of spectral domain optical coherence tomography whether the retinal nerve fiber layer thickness, macular thickness, and foveal volume of the amblyopic and the fellow eyes differ in patients with unilateral amblyopia. Intereye differences in these parameters were found to be insignificant.

Functional Loss of the Inner Retina in Childhood Optic Gliomas Detected by Photopic Negative Response

PURPOSE To determine whether the Ganzfeld ERG photopic negative response (PhNR), an assay of inner retinal activity, is altered in childhood optic glioma (OPG). METHODS Seventeen pediatric patients with a diagnosis of OPG, established on neuro-ophthalmologic and brain/orbit magnetic resonance imaging (MRI) criteria, were enrolled. The examination protocol included determination of visual acuity (VA), fundus examination, retinal nerve fiber layer (RNFL) measurement with spectral-domain optical coherence tomography (SD-OCT) and photopic ERG. Fifteen normal children served as control group. Ten of the 17 OPG patients were retested 1 to 3 months after the first examination. Photopic ERGs were recorded after 10 minutes of light adaptation in response to a Ganzfeld flash presented on a steady light-adapting background. Amplitude and peak-time of b-wave and PhNR were measured. RESULTS Compared with normal values, PhNR amplitude was significantly reduced (P < 0.0001) in the OPG group. Peak-time of PhNR as well as b-wave amplitude and peak-time were similar in both patients and controls. Losses of PhNR were found in patients with involvement of either anterior or retro-chiasmatic optic pathways. Linear regression analysis showed significant positive correlation between RNFL thickness and PhNR amplitude (r2 = 0.34, P = 0.008). Mean percentage test-retest difference for PhNR amplitude and peak-time was 12% and 6%, respectively. CONCLUSIONS These findings indicate that flash ERG PhNR can detect a loss of inner retinal function in childhood OPGs supporting the use of this technique, as an adjunct to standard psychophysical and electrophysiological tests, to monitor visual function in OPG.

Ocular manifestations in Wolf-Hirschhorn syndrome

INTRODUCTION Wolf-Hirschhorn syndrome (WHS) multiple congenital anomalies/mental retardation is caused by partial deletion of the short arm of chromosome 4 and can be considered a contiguous gene syndrome, characterized by typical facial appearance, mental retardation, growth delay, and seizures. METHODS We investigated the ocular defects in a population of 10 patients with WHS and analyzed the relationship between ocular findings and the extent of deletion on chromosome 4. RESULTS The ocular abnormalities found included hypertelorism, strabismus, refractive errors, epicanthal folds, proptosis, downslanting palpebral fissures, microphthalmos, microcornea, iris coloboma, optic nerve coloboma, ocular cyst, ptosis, glaucoma, and nystagmus. Different breakpoints of the chromosomal rearrangement were observed in individual patients, ranging from 4p15.1 to 4p16.3, and the size of chromosomal deletion ranged from 2.6 to 26 million base pairs. CONCLUSIONS Congenital glaucoma and colobomatous ocular cysts have rarely been described in WHS patients that were previously reported. In all cases exhibiting strabismus, an exodeviation was present. Comparing genotype with ocular phenotype, a relationship between the size of deletion and the severity of the ocular involvement was observed in all cases but one.

Walking strategies in subjects with congenital or early onset strabismus

Introduction: In congenital strabismus, sensory adaptations occur hampering the correct development of normal binocular vision. The aim of this study is to investigate if patients with congenital or early onset exotropic or esotropic strabismus adopt different walking strategies with respect to healthy subjects. Our hypothesis is that the abnormal binocular cooperation, occurring in patients with exotropic or esotropic strabismus, could influence neurosensorial adaptation of the gait pattern. Materials and Methods: Twenty-five patients were enrolled: 19 with esotropic (ESO) and 6 with exotropic strabismus (EXO). All patients underwent an ophthalmological and orthoptic evaluation. Biomechanical data were collected using a stereophotogrammetric system and a force platform. Twenty-seven age-matched healthy subjects (HS) were used as controls. Results: The comparison between patients with ESO and patients with EXO strabismus showed that the maximal power at the knee and at the ankle was lower in EXO group (p < 0.01 and p < 0.05, respectively). The step width was statistically different between ESO and EXO groups (p < 0.01), lower in patients with ESO and higher in patients with EXO strabismus when compared with HS (though not statistically significant). The deviation angle values showed a relationship with the step width (at the near fixation p < 0.05) and with the maximal power at the knee and at the ankle (at the far fixation for the knee p < 0.001 and for the ankle p < 0.05; at the near fixation for the knee p < 0.05): in the patients with EXO the increased angle deviation is related to larger step width and to lower power at the knee and at the ankle. In the patients with ESO strabismus this relationship is less robust. Discussion: Patients with EXO and ESO strabismus adopt different strategies to compensate their walking difficulties, and these strategies are likely due to an expanded binocular visual field in patients with EXO and to a reduced visual field in patients with ESO strabismus.

Prevalence of neurological involvement and malformative/systemic syndromes in A- and V-pattern strabismus.

Purpose: To evaluate the prevalence of neurological involvement and malformative/systemic syndromes in A- and V-patterns with respect to other kinds of infantile concomitant strabismus. Methods: A retrospective comparative study of 14,006 consecutive patients examined in the Pediatric Ophthalmology and Strabismus Unit at the Catholic University of Rome between January 2002 and February 2010 was carried out. A total of 2.72% (385) of patients presented with concomitant constant infantile strabismus associated with A- and V- patterns (study group; mean age 8 years; range: 8 months – 37 years; male 211, female 174). Another 377 consecutive patients affected by infantile concomitant strabismus without A- or V- patterns were used as controls (control group; mean age 9 years, range: 1–34 years; male 194, female 183). All patients underwent a complete ophthalmologic and orthoptic examination with ocular motility evaluation and prism cover test or the Hirschberg test in primary, up and down gaze positions, as well as cycloplegic retinoscopy. The angle of deviation was evaluated at near (33 cm) and distance fixation (6 m) with full correction of refraction. Results: Neurological involvement and malformative/systemic syndromes were observed in 30.4% of the study group and in 19.8% of patients in the control group (P < 0.001). Patients with A-pattern showed a greater prevalence of neurological impairment, hydrocephalus and meningomyelocele, while those affected by V-pattern exhibited a greater prevalence of craniosynostosis and malformative syndromes. Conclusions: Neurological involvement and malformative/systemic syndromes seem to be more evident in patients presenting with A- and V-pattern strabismus.

Mydriasis induced by sub-Tenon's ropivacaine injection in patients undergoing strabismus surgery

PURPOSE To investigate the effects of sub-Tenons capsule ropivacaine injection on pupillary diameter in strabismus surgery. METHODS A total of 16 patients were randomly assigned to 2 groups. The ropivacaine group (R) received sub-Tenons ropivacaine 1% (2.5-3 mL) injections. In the control group (C), general anesthesia was induced and a saline solution (2.5-3 mL) was injected in the sub-Tenons capsule. Pupillary diameter was measured at baseline and 2 and 5 minutes from the injections. The effects of the injections were expressed as a ratio of final (5 minutes) versus basal diameter. RESULTS A significant mydriasis occurred in the ropivacaine group when compared with the control group (Group R vs Group C ratio = 2.32, p < 0.0001) or with unoperated fellow eye (R vs unoperated eye ratio = 2.29, p < 0.0001). CONCLUSIONS Ropivacaine in the sub-Tenons capsule induces a mydriasis probably related to a pharmacological ciliary ganglion block.