Esko Aine

Implantable contact lens for high myopia

Purpose: To evaluate the efficacy, safety, and biocompatibility of a collagen polymer implantable contact lens (ICL) (Staar Collamer) as a posterior chamber phakic intraocular lens (IOL) to correct high myopia. Setting: Departments of Ophthalmology, Helsinki University Central Hospital, Helsinki, and Tampere University Hospital, Tampere, Finland. Methods: A Staar Collamer posterior chamber phakic IOL was implanted in 38 eyes of 22 patients with a mean age of 39 years (range 24 to 54 years). The mean preoperative myopia was −15.10 diopters (D) (range −7.75 to −29.00 D). Surgical implantation was performed through a 3.0 mm clear corneal sutureless incision using paraocular anesthesia. The patients were followed clinically up to 3 years. The mean follow‐up was 13.6 months (range 6 to 24 months) for refractive data and 22.3 months (range 6 to 35 months) for complications. The possible inflammatory response to the ICL was measured using a laser flare meter in 12 eyes. Results: Postoperatively, all eyes had a significant increase in uncorrected visual acuity, allowing all but 3 patients (5 eyes) to manage most activities without spectacles. The mean spherical equivalent refraction at the last examination was −2.00 D ± 2.48 (SD) (range +0.13 to −13.00 D), within ±1.00 D of the targeted refraction in 31 eyes (81.6%) and within ±0.50 D in 27 eyes (71.1%). In eyes in which the preoperative myopia was less than −18.00 D (n = 28), the achieved refraction was within ±1.00 D of the intended refraction in 27 eyes (96.4%) and within ±0.50 D in 24 eyes (85.7%). The refraction remained stable with a statistically insignificant change (P > .05) at each interval during the follow‐up. The best corrected visual acuity (BCVA) improved by 1 or more lines in 23 of 32 eyes (71.9%) at 1 year. Two eyes (6.3%) lost 1 line of BCVA. Laser flare photometry showed normal aqueous flare values (11.71 ± 6.61 photon counts/ms) in the 12 eyes measured at least 6 months after ICL implantation. Pupillary block glaucoma requiring surgical intervention occurred in 3 patients (7.9%). One patient (2.6%) developed cataract 1.5 years after ICL implantation; both ICLs were removed, and the refractive errors were corrected by lensectomy and implantation of low‐power posterior chamber IOLs. One patient (2.6%) showed progression of dry macular degeneration at 17 months. Conclusion: At 1 year, ICL implantation had good visual and refractive results with excellent biocompatibility. Long‐term follow‐up is required to confirm that significant complications do not occur in most patients over time.

Refractive errors in a Finnish rural population.

Refractive errors in 611 persons living in a rural area were examined. Males numbered 281 and females 330. The age range was from 6 to 85 years. In 73 (11.9%) persons the refraction was myopic (SER≤‐0.5 D) and in 173 (28.3%) hyperopic (SER ≥ + 2 D). Myopia was most frequently detected in persons aged 21–30 years (22.6%), and the proportion of myopia decreased towards both extremes of age. In all age groups females were more myopic than males. In persons aged 21–60 years the most educated proved to have more myopia and less hyperopia than those with less education. In 158 (25.9%) of the eyes, astigmatism was detectable. The degree of astigmatism changed little with advancing age and was independent of sex. In myopic eyes the range of astigmatic error was wider than in hyperopic eyes. The axis of + cylinders was in hyperopic eyes mostly horizontal and in myopic eyes vertical. Anisometropia of 1.25‐2.0 D was detected in 24 (4.0%) persons and in 19 (3.1%) persons it was over 2 D.

The expression of tenascin and fibronectin in keratoconus, scarred and normal human cornea

Abstract• Background: The etiology and pathogenesis of keratoconus remain unclear, and therefore we decided to study the distribution of different isoforms of tenascin (Tn) and fibronectin (Fn) in normal human corneas and in those obtained from penetrating keratoplasty for keratoconus and corneal scarring. • Methods: Frozen sections of human cornea and conjunctiva were stained by immunohistochemical methods with a panel of monoclonal antibodies (MAbs) against different isoforms of Tn and Fn. • Results: In the normal human eye, Tn was found in the limbal and conjunctival basement membrane region, in the conjunctival blood vessels and at the junction of the cornea and sclera, but no immunoreaction was seen in the normal cornea. In the corneas from the keratoconus patients, a clear immunoreaction for Tn was seen in the defects of Bowmans membrane as well as in the distorted stroma beneath the defects. In some of the keratoconus corneas, basement membrane adjacent to the defects also showed reactivity for Tn, and in clinically and histologically scarred keratoconus corneas the scars expressed Tn. In the scarred corneas, only blood vessels in the posterior portion of the cornea showed immunoreactivity for Tn, while no Tn was noted in the scar area or in Bowmans membrane. No major differencies were noticed in the reactivity of different MAbs against Tn isoforms. Fn, extradomain A Fn (EDA-Fn) and oncofetal Fn (onc-Fn) were found in the basement membrane of the central cornea of the normal eye. In keratoconus corneas, the defects and clinical and histological scars bound MAbs against Fn, EDA-Fn and onc-Fn, but in the scarred corneas no enhancement in the expression of Fns was noted. Extradomain B cellular Fn (EDB-Fn) was not expressed in any of the eyes studied. • Conclusions: The results suggest that the anterior portion of the cornea is involved in the pathogenesis of keratoconus. Furthermore, it seems that the expression of Tn and Fns in the clinically scarred keratoconus corneas is due to a process in which both repairing and scar-forming mechanisms operate at the same time. However, the origin of the defects in Bowmans membrane seen in keratoconus still remains unclear. They may be minor scars due to the disease or primary defects in the process leading to keratoconus.

TRANEXAMIC ACID IN THE PREVENTION OF SECONDARY HAEMORRHAGE AFTER TRAUMATIC HYPHAEMA

The occurrence of secondary haemorrhage after traumatic hyphaema was studied in 239 patients treated in the Department of Ophthalmology, Tampere Central Hospital during the years 1972 to 1980. From 1972 to 1976, 126 patients with traumatic hyphaema were confined to bed and treated without antifibrinolytic agents; nine (7.1%) of these patients developed secondary haemorrhage. From 1977 to 1980, none of 58 patients with traumatic hyphaema treated with tranexamic acid developed secondary haemorrhage which was seen in 3 (5.5%) of 55 patients treated without antifibrinolytic agents; the activities of these patients were not restricted and the eyes were not patched. The resorption of the hyphaema was significantly delayed in the tranexamic acid treated patients. It is concluded that tranexamic acid delays resorption of the blood‐clot sealing the damaged vessel and preventing secondary haemorrhage after traumatic hyphaema without bed‐rest and binocular patching.

EYE INJURIES IN AGRICULTURE

To study eye injuries in agriculture we reviewed the case records of 662 patients with eye injuries treated at the Department of Ophthalmology, Central Hospital of Tampere between the years 1972 and 1979. Of the whole material 96 (14.5%) were agricultural workers, 74 (77%) male and 22 (23%) female, with the mean age of 43 years. The mean annual incidence of eye injuries in agriculture was 3.46 per 10.000 people which was higher than in industry (1.9 per 10.000 people) but lower than in construction (5.28 per 10.000 people). The use of AIV solution was the most frequent cause of eye injury in farming (6/10) and was the most common cause of all chemical eye burns in agriculture (6/7). Cow butting with horn caused all eye injuries in dairying; 50% of these were perforating eye injuries. In lumbering, forest work or a flying piece of wood at chopping caused eye injuries in 29 cases including 19 cases with blunt ocular trauma and 8 cases with perforating eye injuries. Hammering was the most frequent cause of injury in repair work (7/16). Unilateral blindness was seen in 17 cases (17.7%). It was caused mostly by cow butting with horn (6 cases) or lumbering (5 cases). The importance of employment of protective eye screen or glasses also in agriculture is pointed out.

Ophthalmic timolol in a hydrogel vehicle leads to minor inter-individual variation in timolol concentration in aqueous humor

Ophthalmic timolol has been used for decades in the treatment of glaucoma and ocular hypertension, traditionally in aqueous 0.5% eye drops. Recently a timolol 0.1% hydrogel has been developed to improve systemic safety. The aim of the present study was to compare aqueous humor timolol concentrations after administration of 0.1% hydrogel and aqueous 0.5% timolol in patients scheduled for a cataract operation. The concentration in the aqueous humor was 210+/-175 ng/ml (mean+/-S.D.) 2h after administration of timolol 0.1% hydrogel and 538+/-304 ng/ml after aqueous 0.5% timolol. In the aqueous 0.5% timolol group more patients had unnecessarily high concentrations of timolol in the aqueous humor. beta(1)-receptors and beta(2)-receptors were practically 100% occupied after administration of both products. The hydrogel proved to be an excellent formulation in giving smaller inter-individual variation in penetration of timolol into the aqueous humor. Only a weak correlation was seen between corneal thickness and the aqueous humor concentration of timolol in the aqeuous 0.5% timolol group. In conclusion, in contrast to the conventional aqueous 0.5% timolol, 0.1% timolol hydrogel caused only slight inter-individual variation in timolol concentration in the aqueous humor.

Determination of protein content in aqueous humour by high-performance gel filtration chromatography.

High‐performance liquid chromatography (HPLC) was used to study the protein content of aqueous humour in 17 cataract patients. High‐performance gel filtration chromatograms (HPGFC) of the aqueous humour showed 7–12 peaks with low concentrations (mean 0.085 μg/μl) of high molecular weight proteins (peak 1, MW 250 000 or more) and low levels (0.01 μg/μl or less) of IgA (peak 2) and of IgG (peak 3). The fourth peak (MW about 65 000) containing albumin and obviously also trasferrin was the major peak (mean 0.596 μg/μl) at HPGFC of a normal aqueous humour. Lysozyme (peak 6, MW 35 000) occurred in small amounts in the aqueous humour (mean 0.064 μg/μl). The last 6 peaks matched for peptides and amino acids (MW 10 000 or less). It is concluded that HPLC may be a useful preparative method in characterization, separation, and partial purification of immunoglobulins, immune complexes, and other proteins of aqueous humour.

LYSOZYME CONCENTRATION IN TEARS-ASSESSMENT OF REFERENCE VALUES IN NORMAL SUBJECTS

The lysozyme content of tears in 126 healthy persons (249 samples) was studied by an initial rate immunoturbidimetric method. The lysozyme values kept a logarithmic distribution with logarithmic mean 1568 mg/l and median 1530 mg/l. The arithmetic mean with standard deviation was 1678 ± 633 mg/l. Lower lysozyme concentrations were observed in elderly people and children than in adults, but the concentration distributions in different age groups overlapped considerably. Statistically, the difference between the age groups ≥ 60 years and over 60 years was almost significant (P = 0.012). No significant differences occurred between the sexes. Values within ± 2 sn from the logarithmic mean were included in the reference material. For 10–60‐year‐old persons, the reference range is 750–3300 mg/l and over 60 years old 650–2900 mg/l.

Lysozyme content of tears in normal subjects and in patients with external eye infections

We studied the lysozyme content of tears in 267 subjects (521 eyes), including 241 healthy subjects, 7 patients (14 eyes) with bilateral blepharitis, 8 patients (12 eyes) with conjunctivitis, and 11 patients (16 eyes) with keratitis. The concentration of lysozyme in the tears rises with age between childhood and maturity. The highest values were seen in the age group of 21–40 years, and a decrease of lysozyme concentration occurred with an increase in age from 30–40 years. The mean lysozyme content of tears was 1,768 μg/ml in halthy subjects; no significant differences occurred between the sexes. Patients with blepharitis, conjunctivitis, and keratitis had normal mean lysozyme content of tears. The tears of patients with herpes simplex keratitis had low lysozyme values.

Determination of lysozyme in tears by immunoturbidimetric and optimised kinetic bacteriolytic methods

In the year 1922, Sir Alexander Fleming discovered that tears contain a large amount of lysozyme, which works as a protective agent against invasive saphrophytes. Since then human tear lysozyme has been purified and extensively characterized by several authors [ 1,2], and today we have detailed knowledge of its spectral properties, amino acid composition, electrophoretic mobility and immunochemical reactivi ty [ l-4]. Determination of lysozyme in tear fluid has become a diagnostic tool in a number of diseases involving eye complaints. Lysozyme assays have often been combined with the Schirmer test to monitor the excretion rate of tears quantitatively. In general, the excretion rate and the lysozyme content of tears have been assumed to correlate closely, but recently discrepant reports have been presented [5]. Tear lysozyme concentration has been shown to be diminished in the sicca syndrome ]5,6], in patients with herpes simplex virus (HSV) eye infection [7], and in patients with eye complaints arising during beta-blocker therapy [8]. Furthermore, determinations of lysozyme concentration in tears have been used to follow up eye irritation caused by environmental air pollutants 19,101. Assays for lysozyme concentration in tear fluid have been performed most often by the Iysoplate method. This technique is based on the hydrolysis of ~~crococcu~ lysodeikrims cells in agarose gel by the enzymatic action of lysozyme. The technique is apparently simple but has many drawbacks. Lysoplate methods are susceptible to ionic and protein matrix effects [ 11,121, and, moreover, minor quality differences between various agarose batches may cause inconsistency in results [ 131. As an alternative, radial immunodiffusion methods have been developed for tear lysozyme assay [14,15]. However, since these methods are performed in the solid