Giovanni Cennamo

Choroidal Thickness in Primary Glaucoma

A and B scan echography does not allow to measure separately the thickness of the three ocular layers, retina, choroid and sclera. This, however, is possible by radiofrequency signals. 48 eyes of normal subjects and 21 eyes of patient suffering from chronic glaucoma with ocular hypertension from 30 to 45 mm Hg were examined. The thickness of the retina and sclera was equal in the two groups, whereas the thickness of the choroid in the glaucomatous eyes showed an increase of 20% as compared with normal eyes.

Non-Contact Tonometry in Patients that Underwent Photorefractive Keratectomy

To determine the accuracy of non-contact tonometry in patients with corneas thinned by photorefractive keratectomy, the authors measured the intraocular pressure with a non-contact tonometer and the corneal thickness with an ultrasonic pachymeter in 47 patients before and 9 months after photorefractive keratectomy. The patients were divided into three groups according to the degree of treatment: group I between 1 and 5 diopters (14 eyes), group II between 6 and 10 diopters (18 eyes), group III between 11 and 15 diopters (15 eyes). In the first group of patients mean intraocular pressure was 16.1 (+/-3.85) mm Hg before surgery, and 13.2 (+/-3.14) mm Hg after surgery with a significant difference (p = 0.0027). In the second group of patients mean intraocular pressure was 16.0 (+/-4.13) mm Hg before surgery and 13.0 (+/-3.0) mm Hg after surgery with a significant difference (p = 0.0045). In the third group of patients mean intraocular pressure was 17.7 (+/-3.8) mm Hg before surgery and 12.4 (+/-2.6) mm Hg after surgery, with a significant difference (p = 0.0005). In conclusion, according to our results, non-contact tonometry needs a correcting factor for measuring the intraocular pressure in patients that underwent photorefractive keratectomy, related to the degree of refractive treatment.

Visual function before and after photorefractive keratectomy for myopia.

BACKGROUND To date, Snellen visual acuity and postoperative refraction have been used to evaluate the results of photorefractive keratectomy. However, other parameters, such as contrast sensitivity function and glare, may be affected by refractive surgery and lead to unsatisfactory visual performance. This prospective study is aimed at evaluating the effect of photorefractive keratectomy on contrast sensitivity function and glare. SUBJECTS AND METHODS Static contrast sensitivity function, dynamic contrast sensitivity function, and glare sensitivity were evaluated in 22 myopic eyes before as well as 1, 3, and 6 months after photorefractive keratectomy. The eyes tested were divided into three groups, according to the amount of myopia: group I, from -4.00 to -8.00 diopters (D); group II, from -8.25 to -11.00 D; group III, from -11.25 to -20.00 D. RESULTS Both static and dynamic contrast sensitivity function at the intermediate spatial frequencies were altered at 1 month after photorefractive keratectomy, with a trend toward recovery at 3 and 6 months postoperatively. Glare sensitivity was not significantly affected by surgery. CONCLUSIONS Contrast sensitivity function and glare testing may show abnormalities in the presence of optimal visual and refractive results. These tests may result especially important for the evaluation of new refractive surgical procedures.

Refractive Outcome and Corneal Topographic Studies after Photorefractive Keratectomy with Different-sized Ablation Zones

BACKGROUND Discrepancies may still occur between planned and actual refractive correction in eyes undergoing photorefractive keratectomy (PRK). The authors have evaluated the use of an enlarged ablation zone. METHOD A computerized corneal analysis system has been used to compare the changes of the anterior surface of the cornea and the refractive changes before and 1, 6, and 12 months after PRK in 113 patients (119 eyes) treated with an excimer laser. The patients were divided into two groups: those treated with a mask with a 5-mm window (59 eyes), and those with a new mask with different window openings according to the degree of refraction at the corneal apex, starting from 5 mm in diameter for treatments less than 6.5 diopters (D) and from 7 mm in diameter for higher treatments (60 eyes). In the first group, treatment ranged from -2.5 to -16 D (mean +/- standard deviation. -8.5 +/- 3.24 D); in the second group, it ranged from -1 to -14 D (-7.8 +/- 3.06 D). Treatments were evaluated with a chi-square test. RESULTS In the first group of eyes, 46% were within +/-1 D at 1 month, 37% at 6 months, and 39% at 12 months. In the second group of eyes, 73% were within +/-1 D at 1 month, 60% at 6 months, and 58% at 12 months. The comparison between these data and corneal topographic changes shows that both are more stable and predictable with the new mask compared with the 5-mm mask (P = 0.002, 0.02, 0.04, at 1, 6, and 12 months, respectively). CONCLUSIONS The use of larger ablation zones improves the predictability and stability of refractive changes.

Evaluation of Corneal Thickness and Endothelial Cells Before and After Excimer Laser Photorefractive Keratectomy

BACKGROUND The possible endothelial damage induced by photorefractive keratectomy was investigated in myopic eyes. METHODS A morphometric analysis of the endothelial cells was performed in 19 patients before and 2 months after photorefractive keratectomy for the correction of various degrees of myopia. Central ultrasonic pachometry was also recorded at the same examination times. RESULTS No significant changes (p = .816) of the endothelial cell density were found between preoperative and postoperative measurements. The pleomorphic index did not show any significant changes after treatment (p = .955). Central corneal thickness was reduced to a various extent (range from 50 microns to 250 microns) according to the amount of myopic correction intended. CONCLUSIONS Our preliminary data suggest that photorefractive keratectomy for the correction of myopia does not induce endothelial cell damage, at least in the short term.

Correlation Between Refractive and Corneal Topographic Changes After Photorefractive Keratectomy for Myopia

PURPOSE To compare videokeratographic and refractive data obtained before and after photorefractive keratectomy (PRK) for myopia. METHODS Seventy-four eyes underwent PRK for myopia ranging from -2.50 to -17.00 D (mean, -7.76 +/- 3.17 D). All patients had videokeratography with the EyeSys instrument before, and 1 and 6 months after PRK, and the changes in three corneal power measurements (center of the ablation, apex, and effective refractive power) were compared with refractive changes. RESULTS Changes obtained in the three corneal power measurements at 1 and 6 months were well correlated with manifest refraction (Pearsons coefficient ranged from 0.71 to 0.84). CONCLUSION Power measurements obtained with corneal topography, as described above, are a reliable and objective method for the evaluation and follow-up of PRK, provided addition of an approximate 25% correcting factor.

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.

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.

Microperimetry of Subretinal Drusenoid Deposits

Purpose: To investigate light sensitivity in eyes presenting with subretinal drusenoid deposits (SDD). Methods: All consecutive patients with SDD only seen between January 2012 and July 2012 were included. A control group of consecutive age- and sex-matched control subjects presenting at least one eye with early age-related macular degeneration was considered. In all cases best-corrected visual acuity (BCVA), color fundus photography, fundus autofluorescence imaging and spectral-domain-optical coherence tomography with integrated microperimetry were performed. Results: Twenty-one eyes (21 patients, 9 females, 12 males, mean age 69.2 ± 5.3 years, mean BCVA 0.18 ± 0.14 LogMAR) were included in the SDD group. Twenty eyes of 20 patients (13 females, 7 males, mean age 69.1 ± 3.9 years, mean BCVA 0.16 ± 0.15 LogMAR) were included in the control group. In eyes with SDD the choroid was thinner at the subfoveal location, and at 1,500 μm superior, inferior, temporal and nasal to the fovea (p < 0.05). In eyes with SDD, the overall mean light sensitivity in the central macula (4.21 ± 2.46 dB) was significantly reduced when compared to the control group (6.81 ± 2.12 dB, p = 0.001), while stable fixation was present in both groups. Correlation between BCVA and mean light sensitivity in the central 7 × 7 mm square was low in the SDD group (Pearsons rho = 0.4, p = 0.01), while it was good in the control group (Pearsons rho = 0.7, p = 0.001). Conclusions: Eyes with SDD showed reduced sensitivity despite preserved BCVA. Reduced choroidal thickness could be involved in reduction of light sensitivity.

Choroidal Thickness in Open-Angle Glaucoma Measured by Spectral-Domain Scanning Laser Ophthalmoscopy/Optical Coherence Tomography

Aims: To measure macular choroidal thickness in healthy and glaucomatous eyes using spectral-domain scanning laser ophthalmoscopy/optical coherence tomography. Methods: Choroidal thickness was measured in 21 healthy eyes and 16 glaucomatous eyes. Choroidal thickness was measured under the fovea and at 500-µm intervals from the foveal center to 4 mm in the nasal and temporal directions. Vessels were counted in a macular area of 8,000 µm2. Only choroidal vessels with a horizontal diameter of at least 155 µm and a vertical diameter of at least 50 µm were considered. Results: The mean choroidal thickness was greatest below the fovea, i.e. 343.8 µm (SD ±29.06) in controls and 411.56 µm (SD ±33.60; p < 0.001) in the glaucomatous group. The mean vertical diameter was significantly greater (p = 0.008) in glaucomatous eyes (112.18 ± 37.64 µm) than in healthy eyes (103.98 ± 25.67 µm), whereas the luminal area of vessels was significantly larger (p = 0.3) in glaucomatous eyes (39,157.34 ± 21,657.23 µm2) than in healthy eyes (43,779.84 ± 22,874.87 µm2). Conclusions: We show that choroidal thickness is increased in glaucomatous eyes due to an increase in both the vertical diameter and the luminal area of the vessels. This seems to implicate the choroid in the pathogenesis of open-angle glaucoma.