Gilda Cennamo

New formula to calculate corneal power after refractive surgery.

PURPOSE To assess the validity of intraocular lens (IOL) power calculations utilizing a theoretical variable refractive index correlated to axial length after myopic photorefractive keratectomy (PRK) in a clinical simulation and in patients who underwent cataract surgery after PRK for myopia. METHODS Our study included 374 eyes of 300 patients who had PRK for myopia (-2.00 to -12.00 D, mean -4.83 +/- 2.57 D), divided into three groups: Group I had 44 eyes with small ablation zones of 5 to 5.5 mm; Group II had 49 eyes with large ablation zones of 6 to 7 mm; Group III was the control group of 281 eyes (201 patients; 87 males and 114 females) with small and large ablation zones. PRK was performed using the Aesculap-Meditec MEL 60/94 and MEL 70 lasers, and the corneal power was acquired by corneal topography (EyeSys 2000) and a Nidek KM-800 keratometer. RESULTS There was a higher correlation between corneal power and both the change in refraction and axial length when calculated using keratometric measurements. IOL power calculated using keratometric postoperative PRK power was underestimated. The difference between the mean calculated and actual IOL power for emmetropia was 4.30 +/- 2.34 D. A theoretical variable refractive index (obtained from eyes treated with large PRK ablation zones) that correlated with axial length provided the correct keratometric postoperative PRK power: difference between mean calculated and mean actual IOL power was 0.42 +/- 1.23 D. CONCLUSIONS We propose a theoretical variable refractive index that is correlated to axial length. Utilizing this keratometric correct power, we calculated IOL power similar to that for emmetropia.

Computerized Scheimpflug densitometry as a measure of corneal optical density after excimer laser refractive surgery in myopic eyes

PURPOSE: To evaluate changes in anterior corneal optical density and the refractive index after photorefractive keratectomy (PRK) using a rotating Scheimpflug system. SETTING: Department of Ophthalmology, University Federico II, Naples, Italy. DESIGN: Comparative case series. METHODS: Anterior corneal optical density was evaluated with a rotating Scheimpflug system at baseline and 3 months and 12 months after PRK in eyes with a refractive error between −6.00 diopters (D) and −12.00 D (study group). A control group of unoperated eyes with the same refraction range was used to calculate corneal optical density and the Gladstone‐Dale constant in unoperated eyes using the Gladstone‐Dale formula. In the study group, changes in the anterior corneal optical density were evaluated over time and variations in the anterior corneal refractive index were obtained using the Gladstone‐Dale constant. RESULTS: The study group comprised 37 eyes and the control group, 200 eyes. In the study group, the mean anterior corneal optical density and refractive index, respectively, were 27.71 ± 4.39 and 1.360 ± 0.05 at baseline, 37.812 ± 12.31 and 1.491 ± 0.16 after 3 months (P<.001 compared with baseline), and 26.29 ± 4.93 and 1.341 ± 0.06 after 12 months (P=.03 compared with baseline). The mean corneal optical density in the control group was 27.71 ± 4.31 (SD), and the resultant Gladstone‐Dale constant was 0.013. CONCLUSION: An early increase and a subsequent reduction in anterior corneal optical density and the refractive index were present in myopic eyes during 1 year after PRK. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

An Unusual Orbital Lesion: Hepatoma Metastatic to the Orbit

The authors describe a case of histologically proven orbital metastasis from a hepatic carcinoma in an 85-year-old patient with rapid onset of proptosis and visual loss. The clinical diagnosis of orbital metastatic lesion was established by standardized echography and CT scan. To the best of our knowledge, this is only the third histologically proven case of hepatoma metastatic to the orbit.

Evaluation of Morning Glory Syndrome with Spectral Optical Coherence Tomography and Echography

PURPOSE To evaluate eyes affected by morning glory syndrome (MGS) with spectral-domain optical coherence tomography (SD OCT) and echography. DESIGN Prospective case series. PARTICIPANTS Nineteen patients (22 eyes) with MGS observed at the Eye Department, University of Naples Federico II, Naples, Italy. METHODS All patients underwent a complete ophthalmologic examination that included best-correct visual acuity, fundus photography, and echography. Nine patients underwent SD OCT and high-frequency B-scan echography (20 MHz). MAIN OUTCOME MEASURES Spectral-domain optical coherence tomography and echographic findings in MGS. RESULTS Spectral-domain optical coherence tomography revealed retinal detachment in the conus area of 5 eyes: 4 with noncontractile MGS (NCMGS) and 1 with contractile MGS (CMGS). There was evidence of a retinal break in only 2 cases. All 5 eyes had an abnormal communication between the subarachnoid space and the subretinal space. Spectral-domain optical coherence tomography did not reveal differences between CMGS and NCMGS. Echographic examination did not reveal any anatomic abnormalities of the optic nerve or orbit. CONCLUSIONS Spectral-domain optical coherence tomography provides more information than echography about the posterior pole, whereas echographic examination is the only technique that can confirm the anatomic integrity of the optic nerve in the orbital wall. Retinal detachment in MGS generally is ascribed to abnormal communication between the subretinal and subarachnoid or vitreous compartments. These data suggest that myopialike retinal detachment without a retinal break may result from tissue stretching around the peripapillary conus.

Effects on the corneal endothelium six months following photorefractive keratectomy.

Photorefractive keratectomy (PRK) with a 193-nm excimer laser has been shown not to destroy endothelial cells in vivo. However, this laser could damage endothelial cell metabolism, and result in damage over a longer term. In this paper, a comparison between the number and shape of corneal endothelial cells has been performed in 25 patients before and 6 months after PRK. These patients underwent treatment with myopic correction ranging from 2.5 to 17 dpt and with an estimated corneal thinning ranging from 25 to 170 microns. No significant changes in the number (p = 0.167) and shape (p = 0.075) of endothelial cells have been found. These results show that there are no long-term damages after PRK even in severely myopic eyes.

Raman Microspectroscopy Analysis in the Treatment of Acanthamoeba Keratitis

Acanthamoeba keratitis is a rare but serious corneal disease, often observed in contact lens wearers. Clinical treatment of infected patients frequently involves the use of polyhexamethylene biguanide (PHMB), a polymer used as a disinfectant and antiseptic, which is toxic also for the epithelial cells of the cornea. Prompt and effective diagnostic tools are hence highly desiderable for both starting early therapy and timely suspension of the treatment. In this work we use Raman microspectroscopy to analyse in vitro a single Acanthamoeba cell in cystic phase. In particular, we investigate the effect of PHMB at the single-cell level, providing useful information on both the underlying biochemical mechanism and the time frame for Acanthamoeba eradication in ocular infections. Furthermore, we demonstrate that Raman spectroscopy, in conjunction with standard multivariate analysis methods, allows discriminating between live and dead Acanthamoebas, which is fundamental to optimizing patients’ treatment.

Evaluation of Posterior Pole with Echography and Optical Coherence Tomography in Patients with Behçet’s Disease

Background: In Behçet’s disease posterior segment involvement is very frequent (about 80%). Macular edema is the most commonly observed complication and is related to reduction of visual acuity. The purpose of the study was to evaluate choroidal involvement during posterior vasculitis due to Behçet’s disease. Methods: Thirty eyes (15 patients) presenting with posterior vasculitis due to Behçet’s disease were studied. All patients had been evaluated with optical coherence tomography (Stratus OCT, Zeiss) to evaluate the retinal thickness (RT) and with standardized 8-MHz A scan echography to determine the retinochoroidal thickness (RCT). Echographic evaluation with 10- and 20-MHz probes was performed in all cases. Results: In 7 eyes (23.3%), both RT and RCT were normal. In 5 eyes (16.6%), they were both increased. In the other 18 eyes (60%), the RCT was increased while the RT was normal, thus indicating a thickening of the choroid alone. No significant correlation was found between choroidal thickness and the presence of vitreal abnormalities. Neither increases in RT nor those in RCT were significantly related to visual acuity. No correlation was found between RT or RCT and pharmacological treatment. Conclusion: Choroidal inflammation could often play a primary eti- ological role during posterior vasculitis in Behçet’s disease. Echographic detection of choroidal thickening in patients with Behçet’s disease not presenting with retinal alterations or visual symptoms could represent a useful way to detect an early inflammation, in order to start a proper therapy and to influence the final visual prognosis.

Phototherapeutic Keratectomy in the Treatment of Avellino Dystrophy

Avellino corneal dystrophy has rarely been reported in literature. It consists of a combination of granular and lattice dystrophy. Patients may complain of glare and decreased night vision with or without decreased visual acuity, depending on the degree of corneal involvement. Current treatment for this dystrophy includes bandage contact lenses for the erosions or corneal transplant in the case of decreased visual acuity. We describe the first patient with Avellino corneal dystrophy to have been treated with phototherapeutic keratectomy.

Retinal Angiomatous Proliferation

Retinal angiomatous proliferation (RAP) is a distinct form of choroidal neovascularization which may complicate a wet age related macular degeneration (AMD). This exudative-AMD has a peculiar clinical history and prognosis. RAP accounts from 8% to 22% of newly diagnosed cases among patients previously diagnosed as exudative AMD, and up to 25% of the occult or minimally classic CNV. The disease is more prevalent in women (90% of cases) and in elderly patients (around 75 years), and is characterized by a very poor prognosis. The neovascular process, whose retinal or choroidal origin is still object of discussion, often hesitates in the formation of a disciform scar, that evolves into a severe loss of central vision. Treatment for RAP is not yet well established; herein are described the most used therapeutic strategies, starting from laser photocoagulation until the nearest anti VEGF. The opportunity of combination among various treatments to obtain a better effectiveness and a lower frequency of recurrence is also discussed.

Scanning electron microscopy of corneal epithelium in soft contact lens wearers.

Purpose: To use scanning electron microscopy (SEM) to assess differences in corneal epithelium features between soft contact lens (CL) wearers and non-CL wear control. Methods: In a cross-sectional survey, the corneal epithelium removed before photorefractive keratectomy in 10 soft CL wearers (10 eyes) and in 10 non-CL wearers (10 eyes) was evaluated with SEM. The aim of the study was to assess ultrastructural differences in corneal epithelium between the 2 groups. Results: No statistically significant difference was present between the 2 groups as concerns the number of microvilli (P = 0.19). An amount of epithelial mucus >20% was detected in 20% of soft CL wearers and in 80% of non-CL wearers (P = 0.01). A good tolerance to CL was referred by CL wearers. Conclusion: A significant reduction of epithelial mucus at SEM evaluation was present in the CL wearers even in absence of complaints referred to CL.