Lelio Sabetti

Photorefractive keratectomy and LASIK for the correction of hyperopia: 2-year follow-up.

PURPOSE To evaluate the efficacy and safety of photorefractive keratectomy (PRK) and LASIK in the correction of hyperopia. METHODS A retrospective study was conducted on 100 eyes of 56 patients with a mean hyperopia of +2.85 +/- 1.1 diopters (D) undergoing PRK and 100 eyes of 50 patients with a mean hyperopia of +4.49 +/- 1.2 D undergoing LASIK. A Zeiss Meditec MEL 70 G scan laser was used. RESULTS After 24-month follow-up in the PRK group (100 eyes), the mean manifest refractive spherical equivalent (MRSE) was +0.34 +/- 0.92 D (36% +/- 0.5 D). Mean uncorrected visual acuity (UCVA) was 0.87 +/- 0.1; 8 (8%) eyes gained 1 line, 80 (80%) eyes had no loss or gain of lines, 10 (10%) eyes lost 1 line, and 2 (2%) eyes lost 2 lines. In the LASIK group (100 eyes), at 24-month follow-up, the mean MRSE was +0.29 +/- 0.66 D (70% +/- 0.5 D). Mean UCVA was 0.89 +/- 0.1; 6 (6%) eyes gained 2 lines, 10 (10%) eyes gained 1 line, 78 (78%) eyes had no loss or gain of lines, and 6 (6%) eyes lost 1 line. CONCLUSIONS Photorefractive keratectomy and LASIK were both effective and safe in the correction of hyperopia. However, PRK manifested an initial temporary myopic overshoot followed by a hyperopic regression over 24-month follow-up (P < .01) whereas LASIK was associated with a faster refractive stability.

Measurement of Corneal Thickness by Ultrasound After Photorefractive Keratectomy in High Myopia

BACKGROUND Photorefractive keratectomy (PRK) has been used to treat myopia in human eyes since 1988. METHODS We evaluated corneal ablation depth after excimer laser myopic photorefractive keratectomy with the Summit Technology ExciMed UV200LA laser. Preoperative refraction was: mean 9.58 diopters (D) +/- 2.01, (range 6 to 17). We used ultrasound pachometry (1640 m/sec) in 40 eyes of 33 patients. Mean follow-up was of 49.5 weeks (range 16 to 76). RESULTS The measurement of the corneal thickness showed a reduction of the initial thickness followed by an inconsistent increase caused by wound healing and tissue proliferation. CONCLUSION The data showed no direct correlation between diopters of refractive correction and the change in corneal thickness.

Convergence Defects in Patients with Temporomandibular Disorders

ABSTRACT The aim of this study is to show the presence of a correlation between ocular convergence defects (OCD) and temporomandibular disorders (TMD) among a group of adult subjects. The group studied was made up of 48 subjects (12 males and 36 females). The average age was 35 with a range of 19–45 years of age. The subjects presented with TMD and muscular pain and/or dysfunction. Forty-eight subjects with TMD for the case study were matched by gender and age to 48 control subjects seeking routine dental care (control group). All the subjects were examined by the same orthoptist who classified the ocular convergence degree using two tests. The first test evaluated the distances (in centimeters) of the convergence near point (3–4 cm: normal; 5–7 cm: sufficient; >7 cm: insufficient). The second test assessed the fusional convergence using a Berens prism test (>25 diopters: normal; between 18–25: sufficient; <18 diopters: insufficient). In the TMD group, 36 subjects (75%) showed a compromise of convergence: 13 (36%) were classified in the 5–7 degree range and 23 (48%) in the >7 cm degree range. The Berens test showed ten subjects (28%) in the group <18D and 26 (72%) in the group 18–25D. The control-group presented ten (21%) subjects with compromise of convergence: three classified in the group <18D and seven in the group 18–25D. The TMD subjects presented a higher statistical percentage (p<0.0001) of ocular convergence defects. The TMD patients also reported a strong association referred to specific signs and symptoms, i.e., limited maximal opening or myofascial pain. There were some subjective reports also of headaches and torcicollis (neck stiffness) which appeared significantly more frequently in subjects with a compromise of convergence. The study showed a much higher prevalence of ocular convergence defects in patients with head, neck, and shoulder pain.

Effect of Centering Excimer Laser PRK on Refractive Results: A Corneal Topography Study

Computer-assisted analysis of corneal topography, using an EyeSys Corneal Analysis System instrument, was performed on 20 normally sighted human eyes that underwent excimer laser photorefractive keratectomy (PRK) to correct high myopia from 6.00 to 17.00 D (mean 10.90 +/- .SD 2.90 D). Ablations utilized one or two zones, at a single time, with an ExciMed UV200 193-nanometer excimer laser (Summit Technology, Inc, Waltham, Mass). Mean follow up was 28.9 weeks (+/- 13). Decentered treatment caused an average error of 1.06 D in the attempted refractive result.

Standardized echography, pattern electroretinography and visual-evoked potential and automated perimetry in the early diagnosis of Graves' neuropathy

Twenty-four patients (47 eyes) affected by Graves’ disease were enrolled to evaluate the role of standardized echography, pattern electroretinogram (P-ERG), visual evoked potentials (P-VEPs) and automated perimetry in the early diagnosis of the compressive optic neuropathy (CON). The P-ERG amplitude reduction was the most sensitive parameter to demonstrate an early impairment of the optic nerve (ON) function. We found a significant negative correlation between the ON diameter and the P-ERG amplitude. VEPs responses were also altered, but their ability in detecting an early ON damage was less sensitive and specific than P-ERG. The visual field damage was often aspecific and delayed with respect to electrophysiological alterations.

Alterations of the Internal Reflectivity of Extra-Ocular Muscles Associated with Several Clinical Stages of Graves’ Ophthalmopathy

In the period between February 1992 and June 1996, the authors performed extra-ocular muscle echobiometry on 163 patients with Graves’ disease. The aim of this study is the evaluation of changes occurring in several clinical stages. The authors noted an increase in internal muscular reflectivity in the advanced phases and an irregular structure in the early stages. Controversial results in the literature warrant mastery of the method and further research.

Power Doppler Ultrasonography in Ocular and Orbital Diseases

Purpose: The authors present a preliminary report to test the usefulness of a new technique called power Doppler ultrasonography (PD) in the study of orbital vessels. Material and Methods: The ophthalmic artery and vein as well as the central retinal artery and vein have been examined in 10 patients with a General Electric Logiq 5000 that allows the examination with both color Doppler ultrasonography (CD) and PD. Results: PD does not alias, is relatively angle independent and is able to better detect the pathways of these vessels. Conclusions: PD is a new promising technique that may be superior to CD in detecting orbital and ocular vessels.

Eventual Error Caused by Dehydration with Pachometry

Among the possible variables responsible for systemic errors in the acquisition of pachometric measurements, the corneal hydration condition plays a determinant role. In the present study, the authors have investigated the importance of this condition with two different pachometers (Storz Corneoscan II and Allergan Humphrey), reproducing an experimental dehydrated condition. The main datum arising from the comparison of the measurements obtained is represented by the different time course of the value of the measurement in the two groups. In fact, confronting the medium initial superimposed thickness value in the two tables (521 vs. 520 µm) there is a substantial difference in the final examination. For the first group of 60 corneas, the thickness values appear almost identical in the different intervals of time (medium initial thickness 521 vs. 512 µm final thickness). For the group examined with the solid-point machine, a decreasing thickness equal to 7% was evidenced (520 vs. 482 µm) with a significant decrease in the corneal thickness after only 45 s.

Posterior scleritis : Ultrasound findings in two cases

Two cases of posterior inflammatory scleritis are described. The authors show the echographic findings, pointing out the helpfulness of diagnostic ultrasound and the crucial role in monitoring these diseases with A scan examinations to obtain clear results of therapy, even if subjective symptoms disappear.

An adolescent treated with rapid maxillary expansion presenting with strabismus: a case report

IntroductionFew in vivo studies have investigated the effect of maxillary expansion on strabismus; however, some in vitro studies hypothesized that changes in the palatal width obtained with rapid maxillary expansion appliances could involve other bone structures that contain blood vessels and nerves conveying to the orbital cavity. The present case report seems to support that hypothesis, even if no analysis of pathogenetic mechanisms could be drawn.Case presentationWe present the case of a 14-year-old Caucasian girl affected by strabismus and referred for the treatment of a class III malocclusion with transverse maxillary deficiency, which was corrected by the application of a rapid maxillary expansion appliance (Haas type). At 2 months follow-up, the patient, who had not undergone any ophthalmologic treatment, was submitted to an ophthalmologic examination that revealed a marked change in the vision defect, which slightly relapsed at 6 months.ConclusionsThe results of our clinical evaluation showed a remarkable modification of the oculomotor system of our patient as an outcome of the rapid maxillary expansion.Further studies are needed to clarify these findings and to investigate the clinical implications of these observations.