Asymptomatic Eyes Research Articles

Defining Subclinical Keratoconus Using Corneal First-Surface Higher-Order Aberrations

To describe corneal higher-order wavefront aberrations of clinically inconspicuous fellow eyes in patients with early keratoconus (KC). Prospective comparative case series, conducted at a university eye hospital outpatient clinic. Twenty-three eyes (group 1) were newly diagnosed with KC; 10 eyes (group 2) were asymptomatic fellow eyes that showed neither major topographic anomaly nor clinical signs of KC; 127 healthy eyes of 74 patients served as negative controls (group 3). A seventh-order Zernike decomposition of first-surface aberrations was performed. Single Zernike coefficients, higher-order aberration root mean square (HOA RMS) values, the Z3 index and the output values of discriminant analysis D(13) (with input from groups 1 and 3) and D(23) (groups 2 and 3) were assessed for their usefulness to discriminate between clinically normal fellow eyes, KC eyes and controls by plotting receiver-operating characteristic (ROC) curves. There were significant differences between group 1 and group 3 for 11 Zernike coefficients, Z3, total HOA RMS, coma RMS and third-order RMS. Group 2 and 3 showed significant differences only for the coefficients Z(3)(-1) and Z(5)(-1). Z(3)(-1), D(13), and D(23) discriminated between groups 1 and 3 with maximum sensitivity and specificity. For discrimination between groups 2 and 3, D(23) turned out to be the best parameter (A(z) ROC = 0.98), followed by Z(3)(-1) (A(z) ROC = 0.96). Clinically normal fellow eyes of eyes with early KC showed significant differences of first-surface aberrations compared to normal eyes and could therefore be considered as eyes with subclinical KC.

Quantitative Assessment of Dacryoscintigraphic Images in the Evaluation of Epiphora

Background: At the present time, only visual analysis is implemented on dacryoscintigraphic images and quantitative assessments are not routinely obtained. The authors have designed a novel, simple, quantitative method for the diagnosis of sac and post-sac obstructions based on the dacryoscintigraphic images. Method: Fifty-nine patients with severe unilateral epiphora were included and the contralateral asymptomatic eyes were used as controls. After ocular instillation of 0.1 cc isotonic saline containing 4 MBq 99mTcO4, dynamic images were obtained for 20 minutes. Visual interpretation was done by two blinded specialists in nuclear medicine. A Time-Activity Curve (TAC) was generated for each eye and its pattern was divided to plateau type, shallow-down sloping and deep-down sloping. The excretion ratio (expressed as the percentage of drained activity) in the 2nd, 3rd, 5th, 7th, 10th, 15th and 20th minute of the study was calculated based on the following formula: (the total count in the region of interest (ROI) in the 1st minute – the total ROI count in the 2nd, 3rd, 5th, 7th, 10th, 15th or 20th minute/the total ROI count in the 1st minute) × 100. The results of the quantitative analysis were compared with the clinical symptoms, visual analysis and TAC pattern. Results: At the optimal cut-off points for the 2nd, 3rd, 5th and 7th minute, the sensitivity of the prediction of obstruction was 76%, 72%, 71% and 69%, respectively. The correlation between visual interpretation and the TAC pattern was statistically significant. Conclusion: The quantitative evaluation of dacryoscintigraphic images would contribute greatly to achieving an easier and more objective interpretation of the scintigraphic results and also provides a reliable tool for inter-individual comparison and the follow-up of patients. As it is the first time that this innovative method has been examined clinically, it will be necessary to investigate its clinical utility in a larger series of patients.

Utility Assessment to Measure the Impact of Dry Eye Disease

Utility assessment is a formal method for quantifying and understanding the relative impact of a given health state or disease on patients. In this article, methodology of utility assessment is explained and illustrated, and results of an original study are reported. The study was conducted to determine utility values (patient preferences) associated with dry eye disease and compare them to other disease utilities, as well as to compare patient and physician assessments of disease. Forty-four patients in the United Kingdom with moderate to severe dry eye were surveyed via interactive utility assessment software. Utility values were measured by the Time Trade-Off (TTO) and Standard Gamble (SG) methods and adjusted to scores from 1.0=perfect health to 0.0=death. patients reported utilities for: self-reported current dry eye status, self-reported current comorbidities, various dry eye severities, and binocular and monocular painful blindness. patient's dry eye severity was independently classified by patient and physician assessments. Correlation analyses (pearson) were performed between patients' current dry eye utilities and the physician-assessed severity. Agreement between self-reported and physician-reported patient severity was analyzed (Kappa). patients reported higher utilities for their current dry eye condition than for monocular and binocular blindness (SG:0.84>0.60>0.51; TTO:0.67>0.43>0.38). Using TTO, the mean score for asymptomatic dry eye (0.68) was similar to that for “some physical and role limitations with occasional pain” and severe dry eye requiring surgery scored (0.56) similarly to hospital dialysis (0.56-0.59) and severe angina (0.5). Utilities described for scenarios of dry eye severity levels were slightly higher for patients self-reported as mild-to-moderate versus those self-reported as severe. For current dry eye condition, mean utilities for these groups were 0.72 for self-reported mild-to-moderate and 0.61 for self-reported severe. Utilities for dry eye were in the range of conditions accepted as lowering health utilities. Severe dry eye utilities were similar to those reported for dialysis and severe angina, highlighting the impact of dry eye disease on patients.

Inert intraocular eyelash foreign body following phacoemulsification cataract surgery

We describe the first reported case of tolerated eyelash inoculation following phacoemulsification surgery, with 4 years follow-up, that did not result in endophthalmitis or low grade chronic uveitis. A 79-year-old man with bilateral cataracts underwent phacoemulsification and posterior chamber intraocular lens implantation in the right eye. Three months later, he was found to have an eyelash within the right anterior chamber. The patient opted to leave his asymptomatic right eye alone. Four years later, he was referred to our hospital for review of his intraocular foreign body. He had remained asymptomatic with bilateral 6/6 vision, and without pain, photophobia or monocular diplopia. He declined surgery to remove the foreign body and opted for annual review. Intraocular implantation of cilia is a rare surgical complication following cataract surgery. The reaction of the eye to cilia has been reported to be variable and unpredictable, varying from absolute lack of reaction to endophthalmitis. Careful preoperative preparation can prevent similar incidents with potential complications. The position of the cilium is an important consideration. In contrast to other organic materials, a cilium is relatively inert and is rarely associated with infection. Acute inflammation most commonly occurs within days or after a few months, although the eye can tolerate the cilium for many years. Some ophthalmologists prefer observation, particularly when there is no inflammation present. We believe that each patient should be considered on an individual basis. The decision to remove an intraocular eyelash remains controversial and should be considered at the onset of inflammatory or infective clinical signs.

Effect of Artificial Tears on Visual Acuity

To study the effect of commonly used preservative free artificial tear, carboxymethylcellulose (CMC) 0.5% (Refresh Plus, Allergan, Irvine, California) on visual acuity in symptomatic dry eye (SDE) and asymptomatic dry eye (ADE) patients. Nonrandomized prospective clinical trial. Prospective study involving 20 patients (40 eyes) with SDE and 20 patients (40 eyes) with ADE, all 40 years and older, were recruited from a clinic setting over a 1-month period. Distance visual acuity was measured by the Early Treatment of Diabetic Retinopathy Study (ETDRS) vision chart and near visual acuity was measured by the Lighthouse Near Vision chart before and 30 seconds after instillation of one drop of CMC. Distance and near visual acuity was measured both with and without correction. The duration of action of CMC was measured at 1-minute intervals until the patient's visual acuity returned to pretear level. In both SDE and ADE groups, uncorrected and corrected near and distance vision showed a statistically significant improvement after the use of CMC (P < .05). There was no statistically significant difference in improvement between the SDE and ADE groups in all categories (P values > .05). The mean duration of improvement of vision was 2.93 minutes in the SDE group and 3.70 minutes in the ADE group (P = .036). CMC 0.5% provides a temporary yet significant improvement in the visual acuity of SDE and ADE patients. The effect of artificial tears on visual acuity may be of diagnostic value in detecting ocular surface abnormality in symptomatic and asymptomatic patients.

A New Night Vision Disturbances Parameter and Contrast Sensitivity as Indicators of Success in Wavefront-guided Enhancement

To determine the level of success of wavefront-guided repair of night vision disturbances after conventional (Munnerlyn) myopic LASIK using a new parameter to describe higher order aberrations, and to compare the improvements to matched myopic LASIK controls who were symptom-free. We developed a single parameter metric to represent raw spherical aberration (RAWS) to functionally describe the cumulative spherical aberration for an eye over a range of physiological pupil sizes. To derive the RAWS parameter, spherical aberration is plotted over pupil analysis zones from 3000 to 6000 microm. The RAWS parameter (unit = microm2) is then equal to the area under the plot. Sixteen eyes treated for night vision disturbances by wavefront-guided repair were each compared to the mean of four matched control eyes (total 64 eyes) treated by aspheric myopic ablation and without night vision disturbances. Contrast sensitivity and RAWs parameter for spherical aberration were determined for each of the repair eyes and control eyes before and after surgery. Following wavefront-guided repair, 76% of eyes were subjectively reported to have night vision disturbances improved by at least 80%. The percentage of eyes within normal contrast range increased from 25% to 80% following wavefront-guided repair (P < .05). For the control eyes, LASIK increased RAWS by 126% (RAWS was 122 microm2 preoperatively and 276 microm2 postoperatively). For the night vision disturbances repair eye group, RAWS at presentation was 104% (563 microm2) above the respective postoperative RAWS control eyes. Following wavefront-guided repair, RAWS was decreased (P < .05) to only 49% (410 microm2) above the postoperative control group. The RAWS parameter enabled a single digit descriptor of overall higher order aberrations for an eye over the principal physiological pupil range. By comparing RAWS parameter changes in wavefront-guided repair eyes to matched postoperative asymptomatic eyes, we were able to determine the magnitude of the deficit in the symptomatic eyes and the relative efficacy of wavefront-guided repair.

Higher-Order Aberrations in Eyes with Irregular Corneas after Laser Refractive Surgery

To investigate the distribution of the eye's higher-order aberrations in postoperative laser refractive surgery patients with visual complaints and highly irregular corneal shapes. Retrospective case-control study. Thirty-three symptomatic postoperative LASIK and/or photorefractive keratectomy eyes with subjective visual complaints not corrected by spectacles more than 6 months after surgery are compared with 46 normal preoperative and 46 asymptomatic successful postoperative conventional LASIK eyes. Postoperative wave aberrations were measured for each patient using a Shack-Hartmann wavefront sensor (Zywave, Bausch & Lomb, Rochester, NY) over a 6-mm pupil. These measurements were averaged across patients with similar corneal topographic diagnoses (central islands, decentered ablations, a new group termed baby bowties, and irregularly irregular corneas). Higher-order aberrations and corneal topography. The average (+/-1 standard deviation) higher-order root-mean-square (rms) wavefront error values (third, fourth, and fifth orders) for the symptomatic patients was 1.31+/-0.58 microm. This was an average of 3.46 times greater than the average magnitude of normal preoperative eyes (mean rms, 0.38+/-0.14 microm), and an average of 2.3 times greater than the average magnitude of asymptomatic successful postoperative conventional LASIK eyes (mean rms, 0.58+/-0.21 microm) over a 6-mm pupil. Higher-order rms wavefront error increased with pupil size, roughly doubling for every millimeter of increasing pupil diameter. On average, eyes with central islands (n = 6) had the most vertical coma (Z3(-1); mean, -1.35+/-0.43 microm). Eyes with central islands and decentered ablations (n = 2) also had elevated amounts of spherical aberration (Z4(0); means of 0.83+/-0.11 microm and 0.69+/-0.29 microm, respectively) compared with successful postoperative LASIK eyes (mean of 0.42+/-0.20 microm). Eyes with a topographic central baby bowtie demonstrated the most secondary astigmatism (Z4(2) and Z4(-2); mean rms, 0.56+/-0.17 microm; n = 3), despite the lowest average higher-order rms (mean, 0.84+/-0.05 microm) among symptomatic topographic subgroups. Eyes with irregularly irregular corneas had a mean higher-order rms of 1.10+/-0.39 mum. Symptomatic postoperative laser refractive surgery patients with irregular corneas have higher-order aberrations that are 2.3 to 3.5 times greater than asymptomatic postoperative LASIK and normal preoperative eyes, respectively. The higher-order aberrations seem to correlate with corneal topography.

FLUORESCEIN ANGIOGRAPHIC FEATURES OF ASYMPTOMATIC EYES IN CENTRAL SEROUS CHORIORETINOPATHY

Analysis of the fundus and fluorescein angiography (FA) features of the asymptomatic eyes in patients of central serous chorioretinopathy (CSC) at initial visit and estimation of the overall magnitude of bilateral pathology. Retrospective observational case series that reviewed the medical records and FA features of 229 consecutive patients between January 1999 and December 2001. Seventy-three (31.88%) patients had symptoms in one eye but signs in both the eyes, of which 70 were selected. Bilateral symptomatic CSC was seen in 29 (12.66%). Thus, overall bilateral involvement was found in 102 (44.54%) patients. FA features of asymptomatic eyes were pigment epithelial detachment (32.85%), fluorescein leak (31.42%), window defect (31.42%), depigmented patches (14.29%), drusen-like deposits (12.85%), pigment clumps (4.29%), retinal pigment epithelial atrophy (4.28%), subretinal precipitate (2.85%), and sensory retinal detachment (5.71%). Forty-three (61.43%) had evidence of chronic subclinical CSC, whereas 27(38.57%) had features of clinically healed CSC. CSC developed in the asymptomatic eyes within 3 to 12 months in four of the 24 followed-up patients. Considerable number of asymptomatic eyes had features suggestive of healed or chronic subclinical CSC. These eyes are at risk for CSC caused by occurrence of active leak(s) from the same or new site(s).

Upper temporal visual field depressions in the fellow eye in posterior acute optic neuritis: ‘knee’ or no ‘knee’, Wilbrand’s concept remains clinically significant

Aim: To determine whether an upper temporal visual field defect can occur in the asymptomatic fellow eye of patients with acute optic neuritis affecting the posterior optic nerve, suggesting involvement of contralateral crossing fibres (a concept originally proposed by Wilbrand). Methods: A retrospective analysis was performed on 135 patients from two cities with acute optic neuritis. Perimetry results were reviewed to determine whether there was an upper temporal visual field defect in the contralateral healthy eyes of those patients with posterior optic nerve enhancement on gadolinium-enhanced magnetic resonance imaging. Results: Abnormal enhancement of the intracranial optic nerve immediately anterior to, but not including, the optic chiasm was seen in nine patients. Of these, two cases exhibited superior temporal visual field defects in their contralateral healthy eyes. Repeat examination 12 days later in Case one and 24 days later in Case two revealed resolution of these defects. Conclusions: An acute lesion of the posterior optic nerve in optic neuritis can occasionally give rise to an upper temporal visual field depression in the asymptomatic fellow eye in the apparent absence of chiasmal involvement. These cases could indicate the involvement of crossing fibres which are ‘junctional’ in the sense that they follow a course closely associated with the junction of the posterior optic nerve and chiasm.Whether or not such fibres cross the junction into the posterior optic nerve, as suggested by Wilbrand, but recently refuted by Horton, the localising value of such field defects remains clinically significant.

Uveal metastasis from breast cancer in 264 patients

Purpose Breast cancer is an increasingly important health problem in women and is the most common tumor to metastasize to the uvea. This study was designed to evaluate the clinical features, management, and prognosis of patients with uveal metastasis from breast cancer. Design Retrospective interventional case series. Methods We retrospectively reviewed 264 consecutive patients with uveal metastasis from breast cancer. We assessed the clinical features of the patient and tumor at the time of presentation, management, and prognosis. Kaplan-Meier survival estimates were used to analyze the probability of death as a function of time. Results Uveal metastasis was the initial manifestation of breast cancer in seven patients (3%) and the first systemic metastatic site of previously diagnosed breast cancer in 43 (16%). Associated with uveal metastasis, optic disk metastasis was found in 13 patients (5%), eyelid metastasis in one patient (1%), and conjunctival and orbital in one patient (<1%). Of 264 patients with uveal metastasis, 225 (85%) had choroidal metastasis, eight (3%) iris metastasis, two (<1%) ciliary body metastasis, and 29 (11%) had metastasis in multiple uveal sites. In the 264 patients with uveal metastasis, the most common symptom was blurred vision in 197 patients (88%), floaters in 15 (5%), photopsia in 12 (5%), and 19 (7%) were asymptomatic. The uveal metastases were bilateral in 99 patients (38%) and unilateral in 165 (62%). In 55 (56%) of the 99 bilateral cases, a uveal metastasis was found in the asymptomatic fellow eye during follow-up examination. External beam radiotherapy was used in 137 patients with uveal metastasis (52%), providing tumor control in 116 patients (85%) at a mean follow-up of 21 months. Using Kaplan-Meier estimates, survival rates of all patients with uveal metastasis from breast cancer was 65% at 1-year, 34% at 3-year, and 24% at 5-year follow-up. Conclusions Patients with uveal metastasis from breast cancer presented to ophthalmologists with visual symptoms in 93% of cases. However, asymptomatic metastases were commonly detected in the fellow eye. Local ocular tumor control was excellent with current therapies. However, systemic prognosis for all patients, including those who had been treated with different management options, was poor with survival rates of 65% at 1-year and 24% at 5-year follow-up.

A combined analysis of two studies assessing the ocular comfort of antiallergy ophthalmic agents

Background: Many topical agents with similar efficacies are available for the treatment of ocular allergies. In addition to efficacy, comfort is an important criterion because it affects overall patient satisfaction, compliance, and in turn efficacy.Objective: The goal of this study was to compare the comfort profiles of permirolast, ketorolac, cromolyn, and nedocromil ophthalmic solutions using combined results from 2 separate clinical trials.Methods: Two clinical trials were conducted. Adults with asymptomatic eyes were included in the first study. In this single-center, 7-day, prospective, double-blind, single-dose, crossover, parallel-group study, subjects were randomized to be bilaterally dosed with pemirolast, cromolyn, or ketorolac at each of 3 visits. Study 2 was a single-center, 1-day, prospective, randomized, double-blind, single-dose, contralateral, active-control study in which subjects received pemirolast in 1 eye and nedocromil in the contralateral eye. In both studies, subjects completed a pre- and postinstillation ocular comfort questionnaire: the primary variable was overall ocular discomfort, measured on a 4-point scale original to these studies (0 = absent, 1 = mild, 2 = moderate, 3 = severe). Half-increments were permitted. Secondary variables included burning/stinging, foreign-body sensation, tearing, and photophobia.Results: Forty-five subjects (29 women, 16 men; mean [SD] age, 35.9 [12.6] years) were enrolled in study 1; 48 subjects (30 women, 18 men; mean [SD] age, 33.6 [10.2] years) were enrolled in study 2. In study 1, overall discomfort was significantly lower with pemirolast than with cromolyn (P = 0.001) or ketorolac (P < 0.001). In terms of overall discomfort, the number of subjects with a clinically significant increase (⩾1 unit) in score was significantly lower with pemirolast compared with ketorolac (P = 0.021). Burning/stinging and tearing were also significantly lower with pemirolast than with cromolyn (P < 0.001 and P = 0.014, respectively). Mean changes in score compared with preinstillation were consistently lower with pemirolast than with cromolyn for both burning/stinging (P < 0.001) and tearing (P = 0.014). In study 2, overall discomfort was significantly lower with pemirolast than with nedocromil (P < 0.001). The number of subjects with a clinically significant increase in overall discomfort score was significantly lower with pemirolast than with nedocromil (P = 0.007). No changes in ocular tolerability parameters were reported in either study.Conclusion: In these single-dose studies, pemirolast was found to be significantly more comfortable than cromolyn, ketorolac, or nedocromil.

Extracranial Cerebrovascular Revascularization for Chronic Ocular Ischemia

We investigated the demographics, presentation, and outcome of patients undergoing cerebrovascular reconstruction for chronic ocular ischemia (COI) at a single institution through a review of 17 patients over a 9-year period. A total of 558 extracranial cerebrovascular reconstructions were performed during the period of study. Seventeen patients (3%) suffered symptoms of COI. There were 19 symptomatic eyes and 15 asymptomatic eyes. Two patients suffered bilateral symptoms. Eighteen (95%) symptomatic eyes experienced rapidly degenerating global visual acuity, and one suffered bright-light amaurosis. Concomitant ocular pathology was present in 10 (59%) patients, consisting of glaucoma (n = 4), cataracts (n = 4), diabetic retinopathy (n = 3), and macular degeneration (n = 1). Symptomatic eyes were found to have significantly worse ipsilateral internal carotid artery (p = 0.004), external carotid artery (p = 0.002), aortic arch branch disease (p = 0.04), and vertebral artery disease (p = 0.04). All 17 reconstructions treated ipsilateral disease. Twelve patients (70.6%) had significant bilateral disease at the time of operation. Three patients underwent staged contralateral reconstruction. Following revascularization, subjective visual improvement or stabilization occurred in 16 patients (94%). A single patient worsened after developing acute narrow angle glaucoma in the perioperative period. Worse cerebrovascular disease is present ipsilateral to symptomatic eyes. When revascularization is performed, arrest of progression or improvement of symptoms occurs in most patients.

Reduced amplitude and delayed latency in foveal response of multifocal electroretinogram in early age related macular degeneration

AIMTo explore the use of multifocal electroretinograms (MERG) in detecting early changes in age related macular degeneration (AMD).METHOD15 pre-AMD or early AMD eyes showing retinal drusen or irregular fundus pigmentation...

Survival ofSerratia marcescensin the Presence of Complement

Serratia marcescens has been isolated from a variety of ocular infections and/or infammation. In order to survive in the eye, strains must be able to resist host defence systems. Complement has been shown to have an increased concentration and to be active during sleep. Not only is the complement system involved in host defence, but its activation can also produce in ammation. The aim of the present study was to examine the ability of ocular isolates of S. marcescens to withstand complement attack, activate complement and to examine the mechanisms used for evasion of this host defence system. The majority of isolates tested (4/6) were resistant to complement attack. These isolates were able to activate both complement pathways, as detected by enzyme-linked immunosorbent assays (ELISA) and western blotting assays. Components detected included C4, Factor B, C3 and C5. Possible mechanisms of resistance were elucidated including quantity of lipopolysaccharide (LPS) on the cell surface, ability to bind lactoferrin, types of complement components deposited onto the surfaces of strains, and the amount and location of C3 bound on the surface, as determined by transmission electron microscopy. Complement-resistant strains generated iC3b, bound more lactoferrin (1.7 ± 0.6 for resistant cells compared with 0.4 ± 0.2 for complement-sensitive cells, relative values), and had larger amounts of extractable endotoxin (216.8 ± 88.8 µ g/ml for resistant strains and 36.0 ± 48.4 µ g/ml for sensitive strains). Although there was no direct correlation between the ability to resist and activate complement and the isolation of strains from symptomatic or asymptomatic eyes, the resistance of strains to complement may allow these strains to remain in the eye and the activation of complement may contribute to the in ammatory response seen during infection or ocular infammation. Keywords: Serratia marcescens , complement, host defence, tear ?film.

Long-term remyelination after optic neuritis

Thirty-one patients were followed-up, at 3-month intervals for the first year and at 6-month intervals for the second year, after an episode of optic neuritis. The object was to confirm previous evidence for a progressive shortening of visual evoked potential (VEP) latencies and to determine whether this is associated with any change in the clinical ocular examination, visual fields or contrast sensitivity. VEP latencies were found to decrease significantly during both the first and (less strikingly) the second year, the most marked changes occurring between 3 and 6 months. Contrast sensitivity improved during the first 9 months, but subsequently tended (non-significantly) to deteriorate. A similarly transient improvement in central visual field sensitivity was seen in a subgroup of patients with clinically overt multiple sclerosis. In the data from the acutely unaffected fellow eyes, no significant changes in VEP parameters or functional indices were observed. The findings extend those of a previous study which showed significant shortening of VEP latencies between 6 months and 3 years without significant functional improvement. Over this period, a significant prolongation of VEP latencies occurred in the asymptomatic fellow eye, accompanied by contrast sensitivity deterioration. Taken in conjunction, the two studies suggest that recovery processes involving remyelination or, possibly, ion channel reorganization proceed for at least 2 years. The concurrent effects of insidious demyelination and/or axonal degeneration (also occurring in the fellow optic nerve) are initially masked by the recovery process, but gradually become more evident. The functional benefits of the long-term recovery process are relatively minor and are usually reversed within a few years. Nevertheless, it is suggested that long-term remyelination may perform an important role in protecting demyelinated axons from degeneration. Understanding the factors which promote long-term remyelination may have significant implications for therapy in multiple sclerosis.

Detection of staphylococcal superantigens from contact-lens-induced inflammatory diseases.

We investigated the correlation between the production of superantigens in Staphylococcus-aureus-induced ulcer and contact-lens-induced peripheral ulcer (CLPU) and infiltrative keratitis (IK). Twenty-five S. aureus strains used in the study were isolated either from CLPU cases (six), or IK events (13) or asymptomatic eyes (six). A polymerase chain reaction (PCR) was employed to detect genes for superantigenic staphylococcal enterotoxins A-D, toxic shock syndrome toxin-1 and exfoliative toxins A and B. Reversed passive latex aggregation, enzyme-linked immunosorbent assay (ELISA) and immunoblot were used to examine the production of staphylococcal enterotoxins A-D and toxic shock syndrome toxin-1. The frequency of the superantigenic genes was not significantly different among the clinical isolates when asymptomatic isolates were compared with the strains isolated from CLPU and IK events. ELISA and immunoblot showed non-specific protein cross-reactions. The results suggest that detection of superantigenic toxin genes in ocular strains of S. aureus by PCR is a specific, sensitive, rapid and inexpensive alternative to traditional immunological assays. The role, if any, of the S. aureus superantigens in the production of CLPU/IK remains uncertain.

What happens to untreated asymptomatic retinal breaks, and are they affected by posterior vitreous detachment?

Objective The purpose of the study was to ascertain the natural consequences of asymptomatic retinal breaks and to learn what effects, if any, the occurrence of posterior vitreous detachment (PVD) has on such breaks. Design This was a cohort study of consecutive asymptomatic phakic patients, all of whom had asymptomatic retinal breaks, observed without treatment over periods of 1 to 33 years (average, 11 years). Participants There were 196 patients with 235 involved eyes. Intervention Periodic clinical examinations, including binocular indirect ophthalmoscopy with scleral indentation on all eyes and posterior vitreous examination on 50 eyes, were performed. Results In the total study period, one small peripheral retinal detachment developed, without symptoms, from a previous subclinical detachment over a period of 14 years. Nineteen eyes (8%) originally had or developed 22 areas of subclinical detachment, 2 of which were treated because of moderate extension, even though remaining subclinical and without symptoms. Ten eyes encountered acute PVDs, which caused symptomatic retinal tears in three eyes, one of which also had a clinical retinal detachment. Of the 50 asymptomatic eyes examined with Goldmann lens and slit lamp, 12 (24%) were found to have an existing PVD, which had not led to any complication of the previous retinal breaks in any eye. Conclusions Asymptomatic retinal breaks discovered in phakic primary eyes do not show any significant tendency toward clinical retinal detachment, with the exception of a few of those cases that progress to subclinical retinal detachment. It is only some of these, comprising 1% to 2% of the total group, that may justify treatment. Posterior vitreous detachment coexists safely with asymptomatic retinal breaks in phakic primary eyes and shows no tendency to provoke complications to pre-existing breaks at the time of its occurrence.

Morphological changes of the conjunctival epithelium in contact lens wearers evaluated by impression cytology.

Conjunctival changes induced by rigid, gas-permeable and soft contact lenses (CL) were investigated using impression cytology. A scoring system based on seven parameters (specimen cellularity, cell-to-cell contacts, nucleus/cytoplasm ratio, chromatin, goblet cell distribution, keratinisation, inflammatory cells) was used to evaluate the morphological results. One hundred and seventy-two CL-wearing eyes and 40 control eyes were examined. The population was divided into three groups: group 1, control eyes; group 2, asymptomatic CL-wearing eyes; group 3, CL-wearing eyes with intolerance problems. Impression cytology was carried out and all specimens were evaluated according to a scoring system. Group 1 specimens always showed normal features in the conjunctival epithelium. In group 2, rigid and gaspermeable lenses produced greater changes in conjunctival morphology than soft lenses, especially as regards cellularity, nucleus/cytoplasm ratio, goblet cell distribution and total score. On the contrary, in group 3 wearers of soft lenses showed higher partial and total scores than wearers of gas-permeable and rigid lenses. In asymptomatic CL wearers conjunctival morphology was better preserved in wearers of soft lenses. In patients with intolerance problems, wearers of soft lenses showed the worst cytological features. Impression cytology, evaluated with this scoring system, can be used to demonstrate epithelial damage occurring in CL-wearing patients.

The ability of ocular bacteria to bind to fibronectin

Background: Fibronectin enters the tear film during sleep and on reflex tear stimulation. Also, contact lens wearers with increased levels of fibronectin in their tears are more likely to carry greater numbers of bacteria on their contact lenses. This points to a role of fibronectin in mediating adhesion of bacteria to contact lenses.Methods: Bacterial strains isolated from the eyes of contact lens wearers were examined for their ability to bind to fibronectin. Fibronectin binding was examined in solution or adsorbed onto a surface.Results: A strain of Pseudomonas aeruginosa isolated at the time of an acute keratitis and a strain of Stenotrophomonas maltophilia isolated from an asymptomatic eye adhered to soluble or adsorbed fibronectin by greater amounts than other species tested (p < 0.01). Using fibronectin derived from plasma (pFn) and fibronectin derived from cells (cFn) it was shown that the addition of cFn in the presence of pFn increased the binding of pFn to cells indicating aggregation or co‐operativity in binding between the two fibronectin types to the cell surface. P. aeruginosa probably bound to both the protein and carbohydrate moieties of fibronectin. Protein(s) on the cell surface of P. aeruginosa probably mediated the adhesion as digestion of cells with protease significantly (p < 0.01) reduced binding.Conclusions: Bacteria isolated from contact lenses, and in particular gram‐negative bacteria implicated in the production of keratitis, are able to bind to fibronectin. Also, different types of gram‐negative bacteria had distinct abilities to adhere to fibronectin. This may have implications in the binding of these strains to contact lenses in vivo.

Incidence of idiopathic full-thickness macular holes in fellow eyes: A 5-year prospective natural history study

This study aimed to determine the incidence of idiopathic full-thickness macular hole (FTMH) in normal fellow eyes and to evaluate the role of electrodiagnostic and psychophysical tests in identifying eyes at risk. A prospective longitudinal natural history study of a cohort of patients with unilateral holes and normal, asymptomatic fellow eyes without posterior vitreous detachment was conducted. Subjects underwent baseline examination, pattern reversal electroretinography, electro-oculography (EOG), and color contrast sensitivity (CCS) testing for protan, deutan, and tritan thresholds and were recalled for clinical examination at 18 months and 5 years. At baseline, 114 patients were examined. Eighty were available for review at 18 months, of whom 6 had full-thickness macular holes develop in the fellow eye. At 5 years, 67 of the remaining 74 patients who had not developed holes at 18 months were re-examined and a further 5 were found to have holes develop in the fellow eye. A posterior vitreous detachment without hole formation had developed in 20 fellow eyes at 5 years. Although mean pattern reversal electroretinography and EOG responses were within normal limits in affected and fellow eyes at baseline, mean CCS protan, deutan, and tritan thresholds were elevated significantly in affected eyes at baseline (P = 0.0001). Unaffected fellow eyes showed normal mean protan and deutan thresholds, but significantly elevated mean tritan thresholds (P = 0.01) at baseline. Mean tritan CCS loss was, however, similar in fellow eyes in which holes later developed and in fellow eyes in which holes did not. The Kaplan-Meier estimated risk of fellow eye involvement is 15.6% (range, 8.4%-22.3%; P = 0.05) at 5 years. Although electrodiagnostic and psychophysical testing was not predictive of fellow eye involvement, tritan CCS loss at baseline, in apparently normal fellow eyes, may indicate subclinical foveal dysfunction, the nature of which is unclear.