Source of fungus contamination of hydrophilic soft contact lenses.

Fungus infiltration within hydrophilic lenses has been a rare finding. This case report confirms previous findings that fungal contamination of hydrophilic contact lens is possible. The present report, to our knowledge, is the first demonstration of the association of fungus from contaminated cosmetics with hydrophilic contact lenses. It is important to be aware of the possibility of fungal invasion of hydrophilic lenses, as well as to be able to differentiate this from the more common harmless spot formation. On the basis of this study, good lid hygiene, strict adherence to the sterilization procedure, and discontinuance of any soft hydrophilic contact lenses with spot formation seems appropriate.

Lamellar keratoplasty in the treatment of keratoconus: conectomy.

The first 52 eyes of 48 keratoconus patients treated with conectomy and followed for a period of time ranging from 6 to 48 months are included in this study. An average change in the refractive power of the cornea of 10.3 diopters was found after conectomy. The mode for the best corrected visual acuity was 20/30, and the average corneal astigmatism was 3.00 diopters. Photodiagnosis evaluation, microsurgical techniques and instrumentation monofilament nylon, use of the donor cornea minus the endothelium and improved postoperative refractive techniques have combined to make conectomy a reliable and successful form of treatment in keratoconus patients. Both penetrating keratoplasty and conectomy techniques have proven to be successful in the surgical management of keratoconus, and it is the surgeon's responsibility to determine the appropriate approach for the keratoconus patient. Both of these procedures will continue to be refined as ophthalmic technology and surgical skills improve.

A comparison of penetrating keratoplasty and lamellar keratoplasty in the surgical management of keratoconus.

A retrospective study of patients who underwent keratoplasty for keratoconus was done in 100 consecutive cases, of which 50 were penetrating keratoplasty procedures, and 50 were lamellar keratoplasty procedures. Each case was done by the same surgeon in both series. Criteria for patient selection were essentially the same. Postoperative care differed primarily in the time before suture removal, being an average of ten months in the penetrating keratoplasty group and three months in the lamellar keratoplasty group. Of those patients who underwent penetrating keratoplasty, the mean best-corrected visual acuity was 6/6 (20/20-) and the average corneal astigmatism was + 5.00 diopters. Of those patients who received lamellar keratoplasty, the mean best-corrected visual acuity was 6/9 (20/30-), and the average corneal astigmatism was +3.25 diopters. The most frequent complications of both techniques were wound separations that responded well to resuturing.

Aphakic soft contact lens update.

Problems with the N series were mainly due to poor or viable visual acuity that could not be rectified by correcting the residual refractive error in spectacle overrefraction. The error lay mainly in the design of the lens and the fitting rationale. The introduction of lenses (B3 and F3) with base curve and power that adequately covered a wider range of aphakic eyes has solved the fitting problems in most cases. These have been done without sacrificing the simplicity in fitting. Most eyes can be fitted using the B3 series for corneas flatter than 43.00 diopters and the F3 for steeper corneas. The clinical application of the J3 has been found in our hands to be nil. Availability and reproducibility of these lenses are reasons for our preference to fit them for noncontinuous wear in aphakia. In addition, they were found to be a very safe and efficacious correction for the aphakic eye.

Keratoconus and atopic diseases.

In a survey of 162 keratoconus patients, we set out to investigate individual conditions, such as asthma, hay fever, connective tissue syndromes, and eye rubbing, and to determine their relationship of keratoconus. It was found that the prevalence of asthma rises from 0.4% to 1% in the control group to 17.9% in the keratoconus group, or an eighteenfold increase. In addition, the incidence of hay fever in keratoconus patients was found to be 35.7%. As multifactorial disorders, keratoconus and asthma may share some of the multiple genes necessary for the expression of the disorder. Previous findings of excessive eye rubbing in keratoconus patients were confirmed in this study. Finally, we found that the incidence of connective tissue disorders associated with keratoconus was negligible.

Genetics in keratoconus: A, B, O blood groups.

A, B, O blood group frequencies and Rh factors were studied in 69 white keratoconus patients and compared with 1,465 healthy white individuals. We did not detect a significant excess of any particular blood group among keratoconus patients. It was concluded that blood groups were not associated with keratoconus.

Hard contact lens wear as an environmental risk in keratoconus.

We studied 162 keratoconus patients in an attempt to clarify the role of hard contact lens wear in the development of keratoconus. Forty-three (26.5%) of these 162 patients developed keratoconus while wearing hard contact lenses. In a group of 1,248 controls who were fitted for soft contact lenses and observed by us from one year to six years, only one patient developed keratoconus. We demonstrated a circumstantial association between hard contact lens wear and the development of keratoconus, but no cause-effect relationship can be drawn from the existing data. However, we concluded that hard contact lenses do not retard or halt progression of the cone. Hard contact lens wear could not be ruled out as the specific environmental risk factor triggering keratoconus in 26.5% of the patients. If we identify the genetic risk present in this subpopulation, eliminating environmental risks would be an effective means of preventing keratoconus in those predisposed individuals.

Benzalkonium chloride toxicity to the human cornea.

A 36-year-old woman fitted with a soft contact lens after an uneventful extracapsular cataract extraction was wearing her aphakic lens successfully until she switched her lens-soaking solution to an isotonic solution of boric acid, potassium chloride, and sodium carbonate preserved with benzalkonium chloride and edetic acid. After three days her eye became inflamed and vision decreased. No endothelial damage was apparent and the anterior chamber showed 2+ cell and flare reaction. Three weeks after removal of the lens and fitting with an aphakic lens visual acuity was 6/9 (20/30). Study of the preservative by a semiquantitative dilution method together with the clinical evidence in this case proved the cytotoxic effect of benzolkonium chloride when used to sterilize soft contact lenses.

Simplified soft contact lens treatment in corneal diseases.

The advantages and disadvantages of the newly introduced Plano-T soft contact lens for the treatment of corneal diseases were evaluated. The physical characteristics, base curve, diameter, and thickness account for the fitting advantages which make it a versatile lens. The assumption that one lens fits almost any eye and that it may be used in most instances where a bandage lens is indicated proved correct, except for corneas of extreme measurements as in keratoconus. The results obtained compare very favorably with the results of the more conventional lathe cut lenses for the treatment of corneal diseases. Visual improvement does not seem as dramatic as in the latter, but some of the most common side effects are almost eliminated. Its physical characteristics and actions are reviewed. The corneal diseases for which it has been used are mentioned and the results discussed.

Embryopathic effect of ophthalmic EDTA.

Studies on the potential teratogenic effect of topically applied EDTA (0.1% and 3%) were undertaken because of its proven teratogenic effects when administered systemically and because of its wide use as an ophthalmic drug. Although no teratogenic effect was found for either 0.1% or 3% solution of EDTA, 3% EDTA applied topically to the eye six times a day has a significant embryopathic effect, with only 30% of the progeny remaining normal.

HLA antigens and keratoconus.

Significant associations have been found between the HLA antigens or haplotypes and certain diseases and deficiencies. These associations have opened up new areas of clinical investigation. In man, associations have been shown between the presence of Hodgkin's Disease and a number of cross-reacting HLA types (BW5, BW15, BW18), between systemic Lupus erythematosus and HLA type BW15 in Caucasians and BW35 in blacks, between HLA B37 and ankylosing spondylitis in Caucasians, between HLA B8 and gluten-sensitive enteropathy and between HLA B13 and psoriasis, a disease having a strong hereditary element. In ophthalmology, Shin and Becker have shown that the prevalence of HLA B7 and B12 antigens was significantly higher in patients with primary open-angle glaucoma than in the non-glaucomatous population. The purpose of this communication is to report the presence of HLA B27 antigen in the mother and two siblings with keratoconus.

Permanent wear of soft contact lenses in aphakic eyes.

In a five-year study, permanent wear of soft contact lenses was achieved by selecting patients and lenses properly, and offered a viable and probably safer alternative to intraocular lenses. Twenty-five of these 49 patients wore their initial lens or a similar lens continuously for over three years. A visual acuity of 6/12 (20/40) or better was obtained in 45 (91.8%) patients. Four (8%) had ocular problems not related to contact lenses that precluded the same improvement in central vision. The most common complications were reversible epithelial edema, superficial vascularization, and conjunctivitis. There was a strong correlation between edema and superficial vascularization in eyes fitted with lenses having a poorly made inside bevel. Calcium deposits were the most frequently found spot on permanent-wear soft contact lenses (nine eyes, 18%).

Pharmacogenetics in keratoconus.

Genetic markers such as phenylthiourea (PTC) taste has been used as a simple test in genetically determined diseases. A solution of 8.1 mg PTC in 100 ml of water was used as the antimode. The incidence of nontasters in the 50 keratoconus patients tested was similar to that found in the normal population. Under the conditions of this study, a common genetic basis between PTC taste testing and keratoconus is definitely not present.

Teratogenicity of adenine arabinoside (Ara-A).

The potentially teratogenic effect of antiviral drugs, particularly when given systemically, prompted the evaluation of the teratogenic effect of Ara-A when given systemically in doses significantly higher than those used clinically. Under the conditions of this study, neither teratogenic nor embryocidal effects of Ara-A were observed.

The effect of 10-0 running nylon versus 8-0 silk on the healing of corneal gragts.

A previously reported well standardized tensile strength model in rabbits was sued in order to answer whether or not monofilament nylon does in fact delay corneal wound healing in general, and in particular, in corneal grafts. The tensile strength of penetrating keratoplasty wounds closed with either 10-0 running monofilament nylon or 8-0 interrupted black silk was measured in rabbits. The tensile strength of wounds closed with either suture was comparable in all groups. The advantages of 10-0 nylon in corneal transplantation and cataract extraction was presented. In addition, the assumption that the tensile strength of linear central wounds parallels that of a circular trephine wound was proven to be correct.

Antiviral drugs and corneal wound healing.

Using a previously described well standardized wound strength model, the fate of different antiviral drugs from corneal wound healing was evaluated. While 1.0 per cent trifluorothymidine and 0.1 per cent cytosine arabinoside were found to cause a significant delay of central corneal wounds, 0.1 per cent idoxuridine (IDU), three drops four times a day for twelve days, resulted in no significant delay in the healing strength of central corneal wounds.

Hydrogen peroxide sterilization of hydrophilic contact lenses.

A new, simple, and effective procedure for the sterilization of soft contact lenses utilizes hydrogen peroxide, an inexpensive and readily availiable solution.

Ocular penetration of pilocarpine: the effect of pH on the ocular penetration of pilocarpine.

Under the conditions of this study, tritiated pilocarpine was topically applied to rabbits, and the activity in the aqueous humor was measured at selected times. It was found that higher pH affords greater pilocarpine penetration. At pH 7.5, for example, penetration into the aqueous was twice as great as at pH 4.