Toxicity of Topical Antifungal Agents on Corneal Epithelium of Rabbits

Though topical administration of antifungal agents for fungal keratitis is effective, it results various toxic effect on cornea depending on the kinds of agents. So, the authors applied several kinds of antifungal agents on the cornea of rabbit and made a comparative study for corneal epithelial damage of which is related to each agents and instillation time using scanning electron microscope. Forty eyes from twenty rabbits were instilled with 0.15% amphotericin B, 5% natamycin, 1% clotrimazole, 0.2% fluconazole and BSS(as a control) in single drop in each eight eyes and then each two corneas resected and examined after 30 minutes, 1 hours, 3 hours and 6 hours. All antifungals showed toxic effects on the corneal epithelium. Significant loss, elongation or swelling in microvilli, especially at the cell periphery, were noted. The top layer of epithelial cells showed moth-eaten appearance or punched-out lesions, and localized destruction. The surface cells were shrunken with wrinkling of plasma membrane and bulging of nucleous. Part of surface cells lost intercellular attachment leaving retraction fibrils. Rarely first and second layer cells of the epithelium were destructed, exposing third layer cells. Dark cells and premature desquamating cells increased significantly with the lapse of time. In general, 5% natamycin and 1% clotrimazole showed relatively severe epithelial toxicity, on the other hand, 0.15% amphotericin B and 0.2% fluconazole shoed mild epithelial toxicity. Localized damages in the epithelial cells were developed in the early stage, and an extent and the depth of the damage in the cells increased in the course of time after instillation.

Overcorrection, Undercorrection and Astigmatic Change after Excimer Laser Photorefractive Keratectomy of Myopia

We have studied the overcorrection, undercorrection, astigmatic change and its incidence on time sequence after the excimer laser photorefractive keratectomy, and its relation with the degree of preoperative myopia, sex, and age. The study has been done with 429 eyes which we could assess for 6 months or more after excimer laser photorefractive keratectomy of myopia from July 1993 to march 1997. Overcorrection of more than -1D was common during the early postoperative periods and then gradually decreased with time. Overcorrection has been seen in 261 eyes(60.84%) after 1 month, but only 33 eyes(13.47%) after 1 year, and 13 eyes(11.02%) after 2 years. Undercorrection has been seen in 2 eyes(0.47%) after 1 month, but 25 eyes(10.20%) after 1 year, and 20 eyes(16.95%) after 2 years. Surgically induced astigmatism increased to 0.54+/-0.84D after 10 days and then decreased 0.19+/-0.75D after 12 months. Also, surgical induced astigmatism developed 1.13+/-1.10D in 247 eyes (57.58%) after 1 month, but decreased 0.89+/-0.45D in 107 eyes(43.67%) after 12 months. The occurrence of overcorrection and undercorrection was related to the severity of preoperative myopia(p0.05). The amount of postoperative astigmatism was related to preoperative astigmatism(p0.05).

A Case of Lacrimal Gland Duct Cyst Associated with Ptosis

The lacrimal gland ductal cyst is rare, and a closed cyst of the palpebral lobe of the lacrimal gland developing incidiously in the superotemporal cul-de-sac. The authors experienced a case of lacrimal gland ductal cyst, which was a relatively large-sized mass, protruding from the superior temporal conjunctival cul-de-sac. The patient showed temporal blepharoptosis with S-shape of lid margin, but she had no diplopia and limitation of extraocular muscles. The cystic lesion was excised completely through conjunctival approach and lateral canthotomy. Total resection is optimal technique to prevent recurrence. Histopathologically, the cyst contained serous contents in its cavity and its wall was lined by two layers of squamous epithelium, containing some lacrimal gland tissues. This cyst seems to be originated from the palpebral lobe of the lacrimal gland, considering its anatomical location and histopathological findings.

Corneal Haze after Excimer Laser Photorefractive Keratectomy for Myopia

To evaluate croneal haze related to amount of correction, age and sex following excimer laser photorefractive keratectomy(PRK) in myopic eyes, 39months follow-up study on 358 eyes was performed prospectively. The preoperative spherical equivalent refraction ranged from -1.0D to 11.25D(mean -6.18D). The subjective corneal haze grading showed a maximum with mean grading of 0.92 at 2 months and a gradual decrease to 0.14 at 24 months after PRK. The degree of haze was statistically greater with higher amount of correction(p0.05). Clinically significant corneal haze and scarring was frequent in higher myopia group(p<0.05). Individual variation in corneal haze after PRK was found. However, high myopia is a risk factor of the corneal haze following PRK, and further study to decrease the corneal haze after PRK is necessary.