Allergic conjunctivitis: a comprehensive review of the literature

Ocular allergy represents one of the most common conditions encountered by allergists and ophthalmologists. Allergic conjunctivitis is often underdiagnosed and consequently undertreated. Basic and clinical research has provided a better understanding of the cells, mediators, and immunologic events, which occur in ocular allergy. New pharmacological agents have improved the efficacy and safety of ocular allergy treatment. An understanding of the immunologic mechanisms, clinical features, differential diagnosis, and treatment of ocular allergy may be useful to all specialists who deal with these patients. The purpose of this review is to systematically review literature underlining all the forms classified as ocular allergy: seasonal allergic conjunctivitis, perennial allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratocongiuntivitis, contact allergy, and giant papillary conjunctivitis.

Intrasession reproducibility of RNFL thickness measurements using SD-OCT in eyes with keratoconus

BACKGROUND AND OBJECTIVE

To evaluate the intrasession reproducibility of the peripapillary retinal nerve fiber layer (RNFL) thickness measurements obtained by spectral-domain optical coherence tomography (SD-OCT) in eyes with keratoconus and normal eyes.

PATIENTS AND METHODS

Peripapillary RNFL thickness measurements with SD-OCT were repeated three times during the same visit using the eye tracker and retest function in one eye of each participant. Reproducibility was evaluated using within-subject standard deviation (Sw), coefficient of variation (CV), and intraclass correlation coefficient (ICC).

RESULTS

For the overall global RNFL thickness, the values of the three parameters were Sw (± 1.96 standard error) 1.43 ± 0.24, CV 1.28%, ICC (95% confidence interval) 0.969 (range: 0.947-0.983) in control eyes and Sw (± 1.96 standard error) from 1.41 ± 0.26 to 1.57 ± 0.34, CV from 1.18% to 1.37%, and ICC (95% confidence interval) from 0.951 (range: 0.909-0.976) to 0.977 (range: 0.938-0.993) in eyes with keratoconus.

CONCLUSION

Measurement of peripapillary RNFL thickness by SD-OCT shows a good intrasession reproducibility in eyes with keratoconus.

Foveal microstructure and functional parameters in lamellar macular hole

PURPOSE

To evaluate the morphologic features of the photoreceptor layer (by spectral-domain optical coherence tomography) and functional parameters in patients with a lamellar macular hole.

DESIGN

Prospective, multicenter, observational case series.

METHODS

Fifty-four patients with lamellar macular hole were enrolled in the study. All patients underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA) testing, MP1 microperimetry, and spectral-domain optical coherence tomography. For each patient, 2 experienced masked observers evaluated the integrity of photoreceptor inner segment/outer segment (IS/OS) junction and external limiting membrane (ELM) line.

RESULTS

Spectral-domain optical coherence tomography analysis showed complete integrity of the IS/OS junction and ELM line in 40 eyes (group A), partial or complete disruption of the IS/OS junction with an intact ELM line in 8 eyes (group B), and an alteration of both IS/OS junction and ELM line in 6 eyes (group C). Mean BCVA, total retinal sensitivity, and fixation stability were significantly better in groups A and B than in group C (both P < .05, Tukey-Kramer test), whereas there was no significant difference between groups A and B. Mean central retinal sensitivity was significantly different among all 3 groups (all P < .05, Tukey-Kramer test). The grade of integrity of the foveal photoreceptor layer was correlated significantly with mean BCVA (r = -0.57; P < .001), mean central retinal sensitivity (r = 0.52; P < .001), and total retinal sensitivity (r = 0.44; P < .001).

CONCLUSIONS

In lamellar macular hole, the morphologic features of the foveal photoreceptor layer consistently are correlated with BCVA and central retinal sensitivity. Preservation of the ELM is related to the maintenance of visual acuity.

The role of ultrasound biomicroscopy in the diagnosis of temporal arteritis

Temporal artery biopsy is considered the gold standard for the diagnosis of temporal arteritis (TA). The aim of the study was to determine whether ultrasound biomicroscopy (UBM) findings are useful in predicting the result (positive or negative) of temporal artery biopsy in patients with TA. Sixteen consecutive patients (ten women and six men) with clinical diagnosis of TA seen at the Ophthalmology Unit, S. Marta Hospital, Catania University, were included in the study. All patients were submitted to UBM (50-MHz transducer, P45 Plus Paradigm Medical Instruments, Salt Lake City, UT, USA) before temporal artery biopsy. The results were correlated with histopathologic changes. Seven patients presented histopathologic findings consistent with the diagnosis of TA. Thus, UBM findings of these patients were compared with those of the nine patients with negative biopsy. On UBM, we searched for the presence of a hypoechoic effect surrounding the walls of temporal arteries, so-called halo sign, as well as for the intra-arterial middle reflexive filling, so-called intra-arterial filling. The halo sign and intra-arterial filling were found in all seven (100%) patients with biopsy-proven TA. However, in five (55.5%) patients, the absence of these two parameters on UBM of patients with suspected TA strongly suggested that temporal artery biopsy would be negative (negative predictive value, 100%). On the other hand, four (44.5%) of nine patients with negative biopsy presented one of these two UBM findings. In conclusion, this preliminary work suggested UBM to be an appropriate noninvasive tool for morphological imaging and evaluation of temporal arteries, helpful in obtaining an indication of the side and segment for biopsy, and may play a role in predicting negative result of temporal artery biopsy in patients with TA; however, for the time being we cannot recommend any change in the current practice.

Ultrasound biomicroscopic analysis of iris-fixed acrylic intraocular lens in the absence of capsule support

The aim of the study was to investigate postoperative complications and to determine with ultrasound biomicroscopy (UBM) the position of a foldable acrylic intraocular lens (IOL) implanted with a surgical technique of iris suturing in eyes without capsule support. Six eyes with iris-sutured IOLs were examined postoperatively with UBM. The examination included the position of haptics and their relationship to the surrounding structures. Other parameters studied were central anterior chamber depth, IOL iris contact and pigment dispersion. The position of all 12 haptics was determined. All haptics were in touch with the iris. Pigment dispersion was seen in two cases. The anterior chamber depth of the sutured eyes was normal. There was neither cystoid macular edema nor chronic uveitis postoperatively. In conclusion, in most cases surgical placement of iris-fixed lenses is a blind procedure and UBM could be an appropriate method to determine the position of IOL haptics postoperatively and to demonstrate that this surgical technique is reproducible, safe, and effective with the limitation of the difficulty of iris suturing IOL.

Pattern ERG and RNFL thickness in hypertensive eyes with normal blue-yellow visual field

PURPOSE

To evaluate the transient pattern electroretinogram (t-PERG) and the retinal nerve fiber layer (RNFL) thickness in eyes with ocular hypertension (OH) and normal short-wavelength automated perimetry (SWAP).

METHODS

In 26 patients with bilateral OH with normal SWAP, and in 26 age and sex matched healthy controls, t-PERG recording and RNFL thickness measurement were performed. Mean deviation (MD) and pattern standard deviation (PSD) of a reliable full threshold 24-2 SWAP were considered. RNFL thickness was determined by OCT3. Monocular PERG were recorded by using a black and white checkerboard pattern (check size 0.9°, contrast 100 %, mean luminance 80 cd/m2) generated on a monitor and reversed in contrast (four reversals per second, 2 Hz) at a distance of 70 cm. Patients had optimal correction at viewing distance; no mydriatic or miotic eye drops were used. Silver/silver chloride skin electrodes were placed over the lower eyelids in the stimulated eye (active electrode) and in the patched eye (reference electrode); ground electrode was in the Fpz scalp. Peak-to peak amplitude of P50 (N35-P50) and N95 (P50-N95) waves, and implicit time of P50, were considered.

RESULTS

Compared to controls, in OH eyes, a reduction of N35-P50 amplitude (2.86 ± 1.49 vs. 3.77 ± 1.08 microvolts, -24.1 %, t-test p = 0.015), of average RNFL thickness (88 ± 11 vs. 96 ± 10 μm, -9.5 %, t-test p = 0.002), and of RNFL thickness in superior (p = 0.015) and inferior quadrant (p < 0.001), were found. Multivariate analysis showed that in OH eyes, N35-P50 amplitude was inversely related to intraocular pressure (IOP) (p = 0.001); no correlation was found between N35-P50 amplitude and MD, PSD, CCT or RNFL thickness.

CONCLUSIONS

In OH eyes, both PERG and RNFL thickness changes occur in hypertensive eyes with undamaged SWAP; the correlation of PERG amplitude with IOP, but not with RNFL thickness, suggests that such PERG changes are an effect of the IOP on retinal ganglion cells, rather than a sign of their loss.

Functional retinal changes measured by microperimetry in standard-fluence vs low-fluence photodynamic therapy in chronic central serous chorioretinopathy

PURPOSE

To evaluate the effect of low-fluence photodynamic therapy (PDT) on central retinal sensitivity and fixation stability as compared with standard-fluence PDT for treating chronic central serous chorioretinopathy (CSC).

DESIGN

Prospective longitudinal follow-up of patients enrolled in a nonrandomized clinical trial of standard-fluence vs low-fluence PDT in chronic CSC.

METHODS

Forty-two eyes (42 patients) with chronic CSC were enrolled; 19 eyes received indocyanine green angiography-guided standard-fluence PDT (50 J/cm(2)) and 23 received indocyanine green angiography-guided low-fluence PDT (25 J/cm(2)). Retinal sensitivity in the central 12 degrees and fixation stability were evaluated by MP-1 microperimeter at baseline and at 3 and 12 months after PDT.

RESULTS

Mean central retinal sensitivity improved significantly at all time points (at 12 months vs baseline P < .01, Tukey-Kramer test), in the standard-fluence group from 11.9 to 14.4 at 12 months, and in the low-fluence-group from 11.8 to 16.3, with a significant difference between the 2 groups (P = .04, t test). Fixation stability did not change in either group (not significant, analysis of variance). At 12 months' follow-up the retinal sensitivity significantly correlated with best-corrected visual acuity in both groups (standard-fluence, r = -0.52, P = .02; low-fluence, r = -0.54, P = .01).

CONCLUSIONS

The study shows a significant improvement in macular sensitivity after PDT in eyes with chronic CSC, with greater efficacy in low-fluence-treated eyes. Microperimetry data suggest that low-fluence PDT may be a good treatment option in patients with chronic CSC.

Enhanced depth imaging optical coherence tomography of the choroid in idiopathic macular hole: A cross-sectional prospective study

PURPOSE

To determine the choroidal thickness in the macular area in patients with idiopathic macular hole in one eye and an unaffected fellow eye and in healthy controls.

DESIGN

Cross-sectional, prospective study.

METHODS

Twenty-two patients with a full-thickness unilateral idiopathic macular hole and 22 age- and sex-matched controls were recruited. Enhanced depth imaging optical coherence tomography images were obtained by using spectral-domain optical coherence tomography. The choroidal thickness was measured in the subfoveal area and 1000 μm and 2000 μm away from the fovea in the nasal and temporal regions. The diameter of the macular hole and the axial length were determined.

RESULTS

Choroidal thickness was significantly different across the 3 groups at all locations (P < .001, analysis of variance). The choroid was significantly thinner in eyes with idiopathic macular hole and in unaffected fellow eyes than in the control group (P < .01, Tukey-Kramer test). The mean subfoveal choroidal thickness was 183.2 μm in the idiopathic macular hole group, 196.6 μm in the fellow-eye group, and 245.0 μm in the control group. A negative correlation between subfoveal choroidal thickness and axial length was found in all groups (macular hole, r = -0.53, P = .01; fellow eyes, r = -0.56, P < .01; controls, r = -0.52, P = .01); in control eyes, a negative correlation was found between choroidal thickness and age (r = -0.48, P = .02).

CONCLUSIONS

Choroidal thickness was reduced in eyes with idiopathic macular hole and also in fellow unaffected eyes. This may suggest a contributing role of the choroid in the pathogenesis of idiopathic macular hole.

Low-fluence photodynamic therapy in longstanding chronic central serous chorioretinopathy with foveal and gravitational atrophy

PURPOSE

To describe anatomic and functional outcomes in two patients with long-standing severe chronic central serous chorioretinopathy (CSC) with foveal and gravitational atrophy treated with low-fluence photodynamic therapy (PDT).

METHODS

Two patients with a history of over 10 years of chronic CSC and development of gravitational tracts, with best-corrected visual acuity <or=20/200, were treated with PDT guided by indocyanine green angiography (ICGA) with a fluence of 25 J/cm2 at an irradiance of 300 mW. Follow-up examinations 1 and 9 months after therapy included measurement of near and far best-corrected visual acuity, fundus biomicroscopy, fluorescein angiography and ICGA, optical coherence tomography, and microperimetry.

RESULTS

At 1 and 9 months after low-fluence PDT, complete resolution of subretinal, intraretinal, and under retinal pigment epithelium fluid was observed in both patients. Far and near visual acuity improved in both eyes. Improvement of sensitivity and fixation stability were demonstrated by microperimetry. No treatment-related side effects were seen.

CONCLUSIONS

ICGA-guided low-fluence PDT seems effective and safe for treating long-standing chronic CSC.

Prospective, multicenter demographic and epidemiological study on vernal keratoconjunctivitis: a glimpse of ocular surface in Italian population

PURPOSE

To evaluate the frequency and epidemiological features of vernal keratoconjunctivitis (VKC) in Italy.

METHODS

a specific electronic clinical chart for vernal keratoconjunctivitis was created to standardize: 1) medical history; 2) diagnostic criteria; 3) signs and symptoms; and 4) treatments. This study involved 6 Italian referral centers for ocular surface diseases: between March 2005 and March 2006, all referred patients were included, clinical data collected and statistically examined.

RESULTS

The mean age of the vernal keratoconjunctivitis population (n = 156) was 13.8 +/- 8.8 with 64.1% of subjects under 14 years of age and a male/female ratio of 3.5:1. Among VKC patients, 48.7% showed associated systemic allergic diseases. Only 32.1% of patients were positive for RAST and/or prick test. The limbal form (53.8%) was the most frequent subtype of vernal keratoconjunctivitis. Approximately 9% of patients showed a severe form of vernal keratoconjunctivitis. At the first visit patients were treated with: multiple action or mast cell stabilizer eye drops (58.1% and 41.3% of cases, respectively), topical corticosteroids alone (0.6%) or in association (26.8% of cases). All patients used topical steroids at least once in the studied year. Systemic antihistamine therapy was used by 25.6% of patients. In this cohort, 32.7% of patients required two or more examinations per year for exacerbations of their symptoms.

CONCLUSION

Vernal keratoconjunctivitis is a severe ocular condition that mainly affects young males. Vernal keratoconjunctivitis is characterized by different clinical features and therapeutic responses, suggesting the need for a standardized therapeutic approach on the basis of a grading of disease severity.

Correlation of optical coherence tomography pattern and visual recovery after vitrectomy with silicone oil for retinal detachment

PURPOSE

To assess prospectively the features of the macular surface in silicone oil-filled eyes after surgery by analyzing whether silicone oil affects optical coherence tomography (OCT) measurements and their reproducibility and whether a statistical correlation exists between postoperative best-corrected visual acuity (BCVA) and foveal thickness measured by OCT.

METHODS

Twenty eyes of 20 patients underwent vitrectomy with silicone oil tamponade for retinal detachment. After vitrectomy, complete ophthalmic examination including determination of BCVA and OCT was performed to quantify the visual recovery and the foveal thickness.

RESULTS

Ophthalmoscopy revealed that the retina appeared to be reattached in all 20 eyes at 3 months after surgery. BCVA ranged from 0.4 logMAR to 1.7 logMAR, and foveal thickness ranged from 80 microm to 500 microm. Postoperative foveal thickness and BCVA had a strong correlation (r = 0.93; P = 0.003).

CONCLUSION

The presence of silicone oil in the vitreous chamber does not change the reproducibility of OCT measurements of foveal thickness (coefficient of reproducibility, 1.48%). This study showed high statistical correlation between BCVA and foveal thickness. Therefore, postoperative BCVA is affected by postoperative foveal thickness, and visual improvement is limited in eyes with increased or decreased foveal thickness.

The effect of timolol-dorzolamide and timolol-pilocarpine combinations on ocular blood flow in patients with glaucoma

PURPOSE

To investigate the effect of timolol-dorzolamide and timolol-pilocarpine fixed combinations on retrobulbar vessel blood flow.

DESIGN

Prospective, randomized, masked, crossover clinical trial.

METHODS

Sixteen patients with primary open angle glaucoma, treated with timolol 0.5%, received timolol 0.5%-dorzolamide 2% and timolol 0.5%-pilocarpine 2% for four weeks each. Heart rate, blood pressure, intraocular pressure (IOP), and peak systolic (PSV) and end diastolic velocities (EDV) in ophthalmic, central retinal, and short posterior ciliary arteries were measured before and after each treatment, and resistivity index was calculated.

RESULTS

The IOP was reduced (P < .01) by timolol-dorzolamide and, more effectively, timolol-pilocarpine combinations. In central retinal artery, the end diastolic velocity was increased by the timolol-dorzolamide combination (P < .01), resulting in higher end diastolic velocity and lower resistivity index values (both P < .01) compared with the timolol-pilocarpine combination.

CONCLUSIONS

The timolol-dorzolamide combination increases the end diastolic velocity in central retinal artery, despite a lower intraocular pressure decrease, suggesting an effect on retinal circulation.

Intravitreal triamcinolone compared with macular laser grid photocoagulation for the treatment of cystoid macular edema

PURPOSE

To evaluate the outcome of cystoid macular edema (CME) treated with intravitreal injections of triamcinolone acetonide (TA), macular laser grid photocoagulation (MLG), or both (TA+MLG).

DESIGN

Prospective, randomized, interventional, parallel, three-arm clinical trial.

METHODS

SETTING

Institutional clinical study.

PATIENTS

Fifty-six patients (63 eyes) affected by diabetic or retinal vein occlusion CME.

PROCEDURES

Twenty-two eyes received intravitreal injections of 4 mg TA; 21 eyes underwent MLG; and 20 eyes received intravitreal injection of 4 mg TA, and after 3 months, MLG.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (VA), central macular thickness (CMT) (by optical coherence tomography), and postoperative complications.

RESULTS

Mean follow-up was 9 +/- 2 months (range 6 to 12 months). Baseline VA (logarithm of minimal angle of resolution [logMAR]) and CMT were, respectively, 0.82 +/- 0.19 and 556 +/- 139 microm microns for the TA group, 0.84 +/- 0.15 and 601 +/- 102 microm microns for the MLG group, and 0.83 +/- 0.22 and 573 +/- 106 microm microns for the TA+MLG group (no statistically significant difference among the groups). After the treatment, at 45 days, 3, 6, and 9 months in the TA group, VA had improved (P = .004) by 0.26, 0.25, 0.22, and 0.23 logMAR and CMT had decreased by 37%, 33%, 29%, and 31% (P = < .001). In the MLG group, VA was unchanged although CMT had decreased by 5%, 13%, 14%, and 16% (P = .021). In the TA+MLG group, VA had improved (P = .003) by 0.26, 0.24, 0.19, and 0.20 logMAR, and CMT had decreased by 36%, 34%, 28%, and 29% (P = < .001). The groups receiving triamcinolone had better VA and lower CMT values at all time points (P < .05). A reinjection was performed in eight eyes; intraocular pressure increased in nine eyes (treated with medical therapy), and cataract progressed in one eye. No injection-related complications occurred.

CONCLUSIONS

TA intravitreal injection improves VA and reduces CMT more than MLG, which in triamcinolone-treated eyes does not offer further advantages. Intravitreal TA injection could be used as primary treatment in patients with CME.

Keratoconus staging: a computer-assisted ultrabiomicroscopic method compared with videokeratographic analysis

PURPOSE

The aim of this study was to introduce a new paradigm for keratoconus assessment, the keratoconus index (KI), generated from the ratio of peripheral corneal thickness (PCT) to the thinnest corneal thickness (TCT), and calculated by a computer-assisted procedure after ultrabiomicroscope (UBM) examination. Then we compared KI and the keratoconus severity index (KSI), obtained by videokeratography in patients with different stages of keratoconus.

METHODS

We studied 60 eyes with different forms of keratoconus using the TMS-3 autotopographer, provided with a keratoconus screening program (using Smolek-Klyce methods) and the commercial version of the ultrasound biomicroscope (Paradigm UBM Plus Model P45) equipped with a 50-MHz probe, which was provided with our computer-assisted program. The proportion test Z and the correlation coefficient R were applied to the outcomes.

RESULTS

The keratoconus severity index, KSI, obtained by color-coded videokeratographic maps, was in the range 95% to 32% (mean 52.22%). By means of UBM examination, we obtained 60 images and found values of TCT 0.278-0.592 mm and PCT 0.475-0.704 mm. Applying the computer-assisted method, we obtained values for KI of 1.112-2.159 (mean 1.428).

CONCLUSIONS

KI is correlated as well as KSI with the severity of the keratoconus (R = 0.76, P < 0.0001). It can be used as a similar parameter to measure the evolution of the disease, on the basis of corneal thickness rather than the curvature.

A RANDOMIZED PROSPECTIVE STUDY OF RHEGMATOGENOUS RETINAL DETACHMENT CASES TREATED WITH CRYOPEXY VERSUS FREQUENCY-DOUBLED Nd:YAG LASER-RETINOPEXY DURING EPISCLERAL SURGERY

PURPOSE

To evaluate the efficacy of cryopexy versus transpupillary frequency-doubled (532 nm) Nd:YAG laser-retinopexy according to anatomic and functional success and postoperative complications.

METHODS

Seven hundred three patients with primary rhegmatogenous retinal detachment were enrolled. They underwent scleral-buckling surgery using randomly transpupillary frequency-doubled Nd:YAG laser or cryotherapy for retinopexy: patients were observed for a period of 6 months. The primary outcome was anatomic success at 6 months. Secondary outcomes included anterior segment complications, posterior segment complications, and postoperative visual acuity.

RESULTS

There was no significant difference between the primary and secondary outcomes in the two treatment groups: the anatomic success rate was 83% in the transpupillary frequency-doubled Nd:YAG laser group and 83.1% in the cryotherapy group; the rate of postoperative complications and the postoperative visual acuity results are also similar in the two groups; the only barely statistically significant difference (P = 0.045) was the rate of macular holes, which were present only in five myopic patients treated with transscleral cryopexy.

CONCLUSION

Transpupillary frequency-doubled Nd:YAG laser retinopexy, as cryopexy, served as a safe and effective means of creating chorioretinal adhesion during retinal reattachment surgery. The rate of postoperative complications was not influenced by the type of retinopexy.

Prophylactic treatment of the fellow eye of patients with retinal detachment: a retrospective study

BACKGROUND

Controversy exists over the prophylactic treatment of predisposing lesions to prevent retinal detachment.

METHODS

Seven hundred sixty consecutive phakic fellow eyes with rhegmatogenous retinal detachment in the first eye were examined by the same vitreoretinal surgeon before detachment surgery and for a follow-up period ranging from 1 to 72 months, with a mean of 36 months. During this period, in 305 fellow eyes (40.1%) predisposing retinal lesions were present and prophylactic treatments (photocoagulation, cryotherapy or scleral buckle) were performed independently of vitreous status. The results were then compared with the incidence of bilateral RD without prophylaxis reported in Folk and Burton's study of 1982; the two study's data were well matched and showed no significant difference in regards to age, sex, incidence myopia > or =-2.5 and incidence of lattice degeneration. The objective was to investigate whether or not prophylactic treatment is able to avert retinal detachment in the fellow eye.

RESULTS

The age of the patients with peripheral retinal lesions was correlated inversely with the presence of myopia. Nine eyes out of 305 eyes treated (2.9%) developed a retinal detachment, reducing the rate of bilateral retinal detachment to 1.2% (9 eyes out of 760).

CONCLUSIONS

This incidence of bilaterality (1.2%) was lower than the incidence of retinal detachment in fellow eyes not prophylactically treated as reported in the literature, and there exists a highly statistically significant difference between this study's data of 1.2% after prophylaxis and a 13.4% rate of bilaterality as reported by Folk without prophylaxis (P=0.0000).

Vitreous polyamines spermidine, putrescine, and spermine in human proliferative disorders of the retina

BACKGROUND/AIMS

Many cytokines are involved in the pathogenesis of retinal proliferative diseases, but none has been shown to be related to a specific disorder. The aim of this study was to provide a selective marker of diabetes induced proliferative retinopathies.

METHODS

10 vitreous samples from 10 subjects affected by quiescent proliferative diabetic retinopathy (PDR), 20 vitreous samples from 20 subjects affected by active PDR, and 15 samples from 15 patients with proliferative vitreoretinopathy (PVR) were studied. Samples from 18 patients with a macular hole (n = 8) or pucker (n = 10) served as controls. Vitreous samples were obtained via pars plana vitrectomy. The polyamines spermidine, putrescine, and spermine, vascular endothelial growth factor (VEGF), interleukin 8 (IL-8), and transforming growth factor 1beta (TGF-1beta) were measured by high performance liquid chromatography (HPLC) and enzyme linked immunosorbent assay (ELISA), and the correlation coefficients between the vitreous polyamine content and VEGF, IL-8, and TGF-1beta levels were determined.

RESULTS

Spermidine and putrescine were expressed in normal vitreous, but spermine was not detectable. In all the test groups spermidine was 3-4 times higher than in control vitreous and putrescine was similarly lower. The spermine content was up to 15 times higher only in vitreous from patients affected by PDR. Correlation coefficients showed that the spermidine and putrescine level variations correlated with the VEGF and IL-8 content in the active PDR and PVR groups, but not in those with quiescent PDR patients, while spermine was correlated to these cytokines in PDR, but not in PVR groups.

CONCLUSIONS

These data suggest a significant role for spermidine and putrescine as markers of proliferative diseases of the retina. The increase in spermine, restricted to diabetic states, may indicate that this polyamine is a unique and specific index of PDR.

Diabetic patients and retinal proliferation: an evaluation of the role of vascular endothelial growth factor (VEGF)

Vascular endothelial growth factor (VEGF) has been shown to play a major role in intraocular neovascularisation in ischaemic retinal diseases. The aim of this study was to evaluate the concentration of VEGF in vitreous, aqueous and epiretinal membranes of diabetic and non-diabetic patients, with other pathological conditions requiring surgical intervention. Higher VEGF concentration were found in samples from the eyes of diabetic patients versus other pathologies as well as in epiretinal membranes versus the other eye compartments in diabetic patients. However, high VEGF levels were also found in retinal detachment and proliferative vitreoretinopathy of non-diabetic patients. We concluded that VEGF is produced locally and plays a fundamental, but not specific, role in diabetic retinal neovascularisation and proliferation.

Correlation between quantity of silicone oil emulsified in the anterior chamber and high pressure in vitrectomized eyes

PURPOSE

To assess the existence of any correlation between the quantity of silicone oil emulsified in the anterior chamber and the incidence of high intraocular pressure in vitrectomized eyes.

METHODS

Forty-nine eyes of 49 patients underwent vitrectomy with silicone oil injection as an adjuvant procedure. At the time of observation, between September 1999 and September 2000, 13 eyes (26.5%) were phakic; 23 eyes (47%) were pseudophakic; and 13 eyes (26.5%) were aphakic. Ultrasound biomicroscopy, slit-lamp biomicroscopy, and gonioscopy were performed to quantify the presence of silicone oil emulsified in the anterior chamber.

RESULTS

The 13 phakic eyes did not have a high intraocular pressure. In 8 of the 13 eyes, ultrasound biomicroscopy detected only scarce oil emulsification in the anterior chamber (0.304 mm); in 5 of the 13 eyes, gonioscopy and ultrasound biomicroscopy did not detect anterior chamber oil emulsification. Fourteen of 23 pseudophakic eyes had a high intraocular pressure; of these, ultrasound biomicroscopy detected an abundant amount of anterior chamber oil emulsification (0.922 mm). Nine of 23 pseudophakic eyes did not have a high intraocular pressure; of these, ultrasound biomicroscopy detected little anterior chamber oil emulsification (0.209 mm). The 13 aphakic eyes had a high intraocular pressure; of these, ultrasound biomicroscopy detected an abundant amount of anterior chamber oil emulsification (0.795 mm). The coefficient of correlation for the measurements obtained was 0.98 (F = 62.3, P = 0.05; t = 11.1, P = 0.001).

CONCLUSION

This study showed a high correlation between the incidence of high intraocular pressure and the quantity of emulsified silicone oil in the anterior chamber.

Biocompatibility and biodegradation of intravitreal hyaluronan implants in rabbits

To study the biocompatibility and the biodegradation rate in vivo of new intravitreal implants made with three different hyaluronic acid esters: Hyaff7, Hyaff11 and Hyaff11p75 (100% ethyl ester, 100 and 75% benzyl esters, respectively), the plugs were implanted through a sclerotomy at 3.5 mm from the limbus of rabbit eyes. In order to evaluate the in vivo biodegradation the shaft diameter of the plugs was measured by ultrasound biomicroscopy. Slit lamp microscopy, ophthalmoscopy and ERG were performed periodically. The effects of the implants on ocular tissues were also evaluated histologically. All the plugs showed a good biocompatibilitv. Plugs of both the total esters, Hyaff7 and Hyaff11, were found to undergo a slow dissolution process for 60 and 150 days, respectively. The partial benzyl ester, Hyaff11p75, was completely reabsorbed after 15 days. Analysis of variance showed a high correlation between biodegradation rate and the time of resorption (F = 90.5; p < 0.001). The biodegradation rate of each implant is related to the chemical structure of the three types of Hyaff (F = 4.51; p = 0.005). The present data suggest that intravitreal implants based on hyaluronic acid esters represent useful biocompatible and biodegradable devices for a potential drug delivery system in the treatment of posterior segment ocular diseases.

Corneal oedemas: diagnosis and surgical planning with ultrasound biomicroscopy

We used the Humphrey Ultrasound Biomicroscope (UBM System 840 by Zeiss-Humprey Instruments, San Leandro, Calif. USA) to study various corneal oedemas and leucomas. This UBM system, using a high-resolution probe of 50 Mhz, has an axial and lateral resolution of about 50 micrometer. We analysed 36 eyes divided into two groups, 27 (group A) affected by corneal oedema caused by traumatic-mechanic or phlogistic-toxic lesions, 9 (group B) affected by postsurgery oedema. Thanks to its high-resolution power, we could study their pathogenesis and their clinical evolution and so arrange a suitable therapy and perform an accurate follow-up of these pathologies.

Keratoconus staging with ultrasound biomicroscopy

The diagnosis of keratoconus is based on slip-lamp and keratometric findings, and its classification includes 4 different stages. In this study, we compare the ultrasound biomicroscopy (UBM) findings and the keratoconus index (KI) determined using UBM with the severity of the disease. By means of UBM (Humphrey Instruments system model 840) using a 50-MHz probe, we studied 49 eyes affected with different forms of keratoconus. Using a method previously described, we calculated the KI and compared these data with the findings obtained using videokeratography. The mean thickness at the corneal apex in keratoconic eyes was 0.369 mm, while the mean peripheral corneal thickness was 0.568 mm. The mean KI was 1.449 in keratoconic eyes. The KI increased according to the severity of the disease. The mean central keratometry power was 56.95, while the mean amount of steepening of the inferior cornea compared with that of the superior cornea was 8.16. UBM can be considered a useful tool in the study of keratoconus. Using high-frequency ultrasound, it is also possible to obtain reliable measurements of corneal thickness related to the severity of the disease determined by videokeratography.

Ultrasound-biomicroscopic evaluation of filtering blebs after laser suture lysis trabeculectomy

Sometimes in glaucomatous patients treated with trabeculectomy there is no correlation between bleb shape and intra-ocular pressure (IOP). In this study we evaluated the ultrasound biomicroscopy (UBM) features of filtering blebs after laser suture lysis (LSL) trabeculectomy in order to analyse whether its ultrasound-biomicroscopic image can predict the function (IOP).

METHODS

The Humphrey ultrasound biomicroscope, using a high-frequency (50-Mhz) probe, provides high-resolution images of filtering blebs. A total of 103 filtering blebs after LSL trabeculectomy were analysed by UBM. Taking into account the characteristics of internal reflectivity and scleral flap, we classified the blebs into three groups (good, fair, poor) that indicate the bleb function and correlated this UBM pattern with the IOP control (good, borderline, failure).

RESULTS

There was a statistically significant corelation between the UBM classification of function and the IOP control level. Both well-functioning and failed trabeculectomies could be identified by UBM. The UBM images of eyes with good IOP control are characterized by better visibility of the route under the scleral flap and a low reflectivity inside the bleb.

CONCLUSIONS

In accordance with previous studies, we believe that UBM can be a useful method to study and explain the mechanisms of filtering structures and, together with IOP control, to evaluate the bleb function.

Long-term visual results of bifocal intraocular lens implantation

PURPOSE

To evaluate the long-term visual results and variability in contrast sensitivity in patients with heparin-surface-modified (HSM) diffractive bifocal intraocular lenses (IOLs).

SETTING

Institute of Ophthalmology, University of Catania, Italy.

METHODS

In this prospective study, visual acuity (distance and near) and contrast sensitivity were measured in 35 patients who had phacoemulsification with bifocal diffractive IOL (model 811E, Pharmacia) implantation. Patient satisfaction was also evaluated using a questionnaire. Mean follow-up was 20 months (range 18 to 24 months).

RESULTS

At the last examination, mean distance visual acuity was 0.79 +/- 0.2 (SD) without correction and 1.0 +/- 0.15 with best correction. Mean uncorrected near visual acuity was J1.6 +/- J0.77 and with best distance correction, J1.19 +/- J0.49. No statistically significant changes in visual acuity were evident at the last follow-up (Student t test). No changes were found in contrast sensitivity reduction over time, nor were late postoperative complications noted. Overall patient satisfaction was rated as good by 94.3% of patients with best distance correction.

CONCLUSIONS

The diffractive bifocal HSM IOL provided good visual performance for distance and near over time. In relation to the low rate of postoperative complications, the slight contrast sensitivity reduction was stable during follow-up.

[Evaluation of the filtering bleb using ultrasound biomicroscopy]

BACKGROUND

Sometimes in glaucomatous patients treated with trabeculectomy there is not a correlation between bleb shape and intraocular pressure. So we studied the functional anatomy of the filtering bleb by a ultrasound biomicroscope, using high frequency (50 Mhz) probe, which provides high resolution images of filtering blebs.

MATERIALS AND METHODS

A total of 46 filtering blebs of 46 patients after trabeculectomy were analyzed by ultrasound biomicroscopy (50 Mhz). Dimensions, shapes and structure of blebs were evaluated in 2 groups of patients.

RESULTS

It was possible to obtain longitudinal or transverse images of filtering blebs, to measure the height, to evaluate the reflectivity inside and to follow the route under the scleral flap. Blebs with lower reflectivity and a visible route under the scleral flap had a lower intraocular pressure while the height was not important for a good intraocular pressure.

CONCLUSIONS

So ultrasound biomicroscopy can be a useful method to study filtering blebs and also to explain the mechanisms of filtering structures in patients who underwent trabeculectomy.

[Incidence of ROP (Retinopathy of Prematurity) in hypoxemic neonates: case contribution]

In this retrospective study the Authors correlated the hypoxia with the severity of retinopathy of prematurity (ROP) in a population of 683 outborn preterm infants (bw < 2500 g and gestational age < 38 weeks). They excluded all cases with specific pathological conditions. Among neonates with the same gestational age the incidence of ROP was higher (p < .05) in those with hypoxia (pH < 7.25, tcPO2 < 50 mmHg). These data suggest that hypoxia plays a role in the pathogenesis of ROP.

Evaluation of central and peripheral corneal thickness with ultrasound biomicroscopy in normal and keratoconic eyes

PURPOSE

Our study was designed to calculate central and peripheral corneal thickness in patients affected with early stages of keratoconus and in normal subjects using ultrasound biomicroscopy (UBM). To obtain an objective and reliable assessment of the corneal thinning in affected eyes, we developed a keratoconus index (KI) by means of the UBM measurements.

METHODS

By means of the commercial version of the ultrasound biomicroscope (system model 840; Zeiss-Humphrey Instruments, San Leandro, CA, USA) using a 50-MHz probe, we studied 30 normal and affected eyes. In keratoconic eyes, we measured the thinnest corneal thickness (TCT) at the apex of the conus and at four peripheral sites at a distance of 2.5 mm from the central site (peripheral corneal thickness: PCT). The same procedure was performed in the normal eyes. To obtain an objective and reliable assessment of the corneal thinning, we calculated the ratio between the mean PCT and the mean TCT (Keratoconus Index: KI = PCT/TCT), in keratoconic eyes. In normal eyes, the KI was calculated on the basis of the ratio between the mean PCT and the mean central corneal thickness (CCT).

RESULTS

In keratoconic eyes, the mean corneal thickness at the thinnest part of the conus was significantly different from the CCT in normal patients (Student's t test, p < 0.001). The peripheral measurements were not significantly different from keratoconic and normal eyes. The mean KI was 1.482 (SD, 0.095) in the keratoconic eyes, whereas it was 1.189 (SD, 0.086) in the normal subjects. The statistical analysis of the KI calculated on the basis of the UBM measurements showed that the KI values are significantly different from healthy subjects and from keratoconic patients (Student's t test, p < 0.001).

CONCLUSIONS

UBM can be considered a useful tool in the study of keratoconus. We believe that calculation of the KI by means of UBM gives the possibility of obtaining an objective assessment of corneal thinning. Therefore this parameter can be useful in the staging and in the follow-up of these patients.

[Controlled trabeculectomy and incidence of postoperative choroidal detachment]

In this study the authors report their experience with titrated trabeculectomy. It is performed as follows: tight scleral flap trabeculectomy, five or more 10/0 nylon sutures, argon laser lysis of one or more sutures (depending on the eye's postoperative condition) by means of the Hoskins lens. The aim of this technique, performed by the authors for 3 years, is to decrease atalamia and choroidal detachment. Results obtained in 70 eyes of 62 patients with chronic open-angle glaucoma are compared by means of statistical analysis with those in 70 eyes of 66 patients operated on by means of the traditional technique. The incidence of choroidal detachment is significantly reduced (P < 0.001). There is no important difference in ocular pressure and visual acuity. In conclusion, this technique is very useful in controlling and titrating the filtration rate, avoiding an excessive lowering of IOP after trabeculectomy and decreasing the complications.

[Experiences with sclerostomy with the Holmium laser]

The THC-YAG laser (holmium laser) war used to perform ab externo sclerostomies in patients affected by various types of glaucoma. This approach was employed in 48 eyes with diagnoses of medically uncontrolled chronic open angle glaucoma, plateau iris or neovascular glaucoma. Post-operatively, 5-FU was injected. At the tend of the follow-up (mean 10.22 +/- 3.4 months), in 25 eyes (52.1%) the IOP was under control without medical therapy. In 12 eyes (25.0%) it was necessary to use antiglaucomatous topical therapy, and in 11 eyes (22.9%) the IOP was uncontrolled despite therapy. The authors stress the importance of a correct pharmacological protocol before and after operation and describe the surgical technique. They confirm the validity of this approach, owing to its minical invasiveness, the possibility of repeating the procedure, and the low complication rate.

[Determination of contrast sensitivity in patients with silicone oil tamponade]

The issue of whether silicone oil has a toxic effect on the retina is still being debated. In order to verify possible retinotoxic effects, the authors studied the variations of retinal function by means of computerized perimetry on patients who had undergone a vitreoretinal operation with injection of silicone oil in the vitreous cavity. Silicone oil remained in the eyes for a period of 120 days +/- 15.

PATIENTS AND METHODS

14 patients under treatment for vitreoretinal pathologies sparing the macula underwent five examinations (Macular Threshold Test of the Humphrey Field analyzer): two examination during the period silicone oil was in the vitreous cavity (30 days after injection and 10 days before removal) and three examinations after its removal (at 30, 90, and 180 days).

RESULTS

When the paired t-test and ANOVA test were applied to our results, there were no significant differences in the light-difference sensitivity.

CONCLUSIONS

These data do not indicate that silicone oil a retinotoxic effect (revealed by means of computerized perimetry) when it is removed within 4 months.

[Epidemiological,and physiopathological findings in retinopathy of prematurity: the authors' personal cases]

The authors present a retrospective epidemiological study on retinopathy of prematurity (ROP), performed on 738 newborns with a gestational age of 34 +/- 2.41 weeks and birth weight of 1971 +/- 351 g. They excluded all cases with severe respiratory distress and other pathological conditions. First stage of ROP shows no correlation with gestational age and birth weight, whereas second and third stages of ROP show an inverse correlation with the above mentioned factors, particularly birth weight. Among neonates with the same gestational age, the incidence of ROP is higher in those "small for date". Regarding the pathogenesis of ROP, the authors outline the importance of perinatal hypoxia.

MRI and intraocular tamponade media

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, fluorosilicone oil, or perfluorocarbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment.

Surgical management of closed angle glaucoma: our experience

In this paper we present our experience of the last three years in the surgical treatment of eyes with closed angle glaucoma. We have performed an extracapsular lens extraction and posterior chamber intraocular lens implantation on 34 eyes of 34 patients. All of them were affected by closed angle glaucoma with variable control after a Yag laser iridotomy: 6 eyes had high I.O.P. notwithstanding maximal therapy, 11 eyes had I.O.P. under control (less than 21 mmHg) without therapy, 9 with I.O.P. controlled with topical therapy, 8 with I.O.P. controlled with maximal therapy (C.A.I. included). The cases with well controlled glaucoma were operated on because of the presence of a more or less significant lens opacities. After a follow-up of up to 40 months (mean = 20.3, range = 1-40), all eyes show satisfactory intraocular pressure and no eye needed a filtering procedure. The results of our studies are as follows (values are mean +/- SD). In the group of 6 eyes with high I.O.P., the mean pre-operative intraocular pressure was 29.7 +/- 5.6 mmHg and the mean post-operative I.O.P. was 15.1 +/- 1.4 mmHg. The mean reduction was 14.5 +/- 6.6 mmHg (p < 0.005). In the 28 eyes with pre-operative I.O.P. under control (17.5 +/- 1.6), the mean post-operative I.O.P. was 14.4 +/- 2.3 mmHg, with a mean reduction of 3.1 +/- 3.1 mmHg (p < 0.005). Before the E.C.C.E., 11 eyes had I.O.P. less than 21 mmHg without anti-glaucoma medication, whereas after the E.C.C.E. 28 eyes did not need such a medication.(ABSTRACT TRUNCATED AT 250 WORDS)

[A new surgical procedure in angle block glaucoma]

Authors show the results obtained in 29 eyes of 29 patients with closed angle glaucoma operated with ECCE plus posterior chamber IOL implantation. After a follow up varying from 1 to 35 months (mean = 20.7) all eyes are under good control (25 without therapy, 4 with topical therapy) of I.O.P. Authors report on the "rationale" of their surgical approach: particular anatomo-functional features of the eyes affected by closed angle glaucoma. Pre-op. and post-op. biometrical and gonioscopical findings are described and discussed.

Effects of hyaluronic acid fractions in the rabbit eye

Two fractions of hyaluronic acid with different molecular weight (Ial, molecular weight 500,000-730,000 and Healon, molecular weight 750,000) were injected intracamerally or intravitreously in the rabbit eye. Although the fraction with higher molecular weight caused an increase in intraocular pressure, no change of this parameter was found after administration of the fraction with the lower molecular weight. Furthermore, various inflammatory reactions in ocular tissues were observed during slit-lamp biomicroscopy after administration of Healon but not of Ial. No inflammatory reaction was found after subchronic instillation of the compounds.

Fifteen years of experience in retinal surgery

We report our experiences with retinal surgery. The importance of vitrectomy and the use of silicone oil are mentioned although the latter can be responsible for iatrogenic proliferative vitreoretinopathy.

Retinopathy of prematurity (ROP): optimal timing of clinical evaluation and standard procedures

The authors present the protocol currently used in their institution for initial and follow-up evaluation of infants at high risk for developing retinopathy of prematurity (ROP). After topical anesthesia and lid speculum insertion, the examination is carried out using an indirect binocular ophthalmoscope with a +20 or +28-diopter lens. Mydriasis is achieved by instilling one drop of 1% tropicamide, followed by one drop of 0.5% tropicamide + 2.5% phenylephrine 15 minutes later and after an additional 15 minute interval, another drop of 1% tropicamide. If mydriasis is insufficient after one hour, one drop of a 0.5% tropicamide-5.0% phenylephrine solution may be instilled. The initial examination is performed between the third and fourth weeks of life. If any areas of retinal immaturity are found, the examination is repeated every other week and, later, every three to four weeks, until vascularization has reached the ora serrata. Should any sign of ROP be present during the first examination, the patient is examined weekly or every other week depending on the severity of clinical findings.

Effects of dapiprazole on contractile responses of guinea pig isolated ileum

The effects of dapiprazole, a relatively new alpha 1-adrenolytic agent, on contractile responses and on spontaneous mechanical activity were studied in guinea pig isolated ileum. Dapiprazole (10(-10) to 10(-4) M) produced a concentration-dependent inhibition of high K+ (80 mM) -induced contractions. These inhibitory effects were observed with dapiprazole added either before or after the induced contractions. The Ca2+-induced contractions of K+-depolarized ileum were also inhibited by dapiprazole. Dapiprazole inhibited in a non competitive manner the responses of the ileum to: carbachol, histamine, 5-hydroxytryptamine, pentagastrin, angiotensin II and cholecystokinin. In order to analize whether dapiprazole exerts an intracellular effect on Ca2+-store, skinned preparations were used. The results suggest that dapiprazole might inhibit Ca2+ entry through both voltage-and receptor-operated channels of the smooth muscle membrane.

Receptor-responses in fresh human ciliary muscle

The physiological and pharmacological properties of ciliary muscle isolated from fresh human eyes were investigated. The muscle exhibited no spontaneous activity. Concentration-dependent contractions in response to carbachol were competitively antagonized by atropine (pA2 = 8.95). The muscle, precontracted by carbachol (2.7 X 10(-4)M), responded to the application of isoprenaline by concentration-dependent relaxation blocked by propranolol (3.5 X 10(-9)M to 3.5 X 10(-8)M; pA2 = 9.15). Angiotensin-evoked contractions were antagonized by 8-Ala-angiotensin II (4.5 X 10(-8)M) in a competitive manner, but were not inhibited by phentolamine or propranolol. Contractions generated by electrical stimulation of the muscle (30 ms, 20 Hz, 60 pulses) were antagonized by atropine (10(-7) M) and tetrodotoxin (6.3 X 10(-7) M). Phentolamine and propranolol did not influence these responses. An increase of the external potassium concentration ([K+]o) from 5.4 to 158.8 mM produced a mechanical response, antagonized by atropine, but not influenced by tetrodotoxin, phentolamine or propranolol. The human ciliary muscle appears to carry muscarinic and angiotensin receptors and beta 2-adrenoceptors. The estimate of Katropine for muscarinic receptors mediating carbachol-induced contractions agrees with estimates of Katropine reported for human and rabbit iris.