Efficacy and safety of topical diclofenac in reducing ocular pain after excimer photorefractive keratectomy.

PURPOSE: To evaluate the efficacy and safety of diclofenac sodium 0.1% ophthalmic solution in patients having myopic photorefractive keratectomy (PRK). SETTING: Corneal Laser Centre, Clatterbridge Hospital, Wirral, United Kingdom. METHODS: We performed a prospective, randomized, double-masked, parallel-group, placebo-controlled study of 50 patients (diclofenac 25, placebo 25) of both sexes who had myopic excimer laser PRK. Results were evaluated by several types of questionnaires and comprehensive clinical examination on the day of the procedure and 1 and 3 to 14 days postoperatively. RESULTS: Diclofenac-treated patients experienced significantly less photophobia, burning/stinging, and ocular pain and took significantly fewer oral narcotic analgesics over the first 24 hours postoperatively than placebo-treated patients. CONCLUSION: Topical diclofenac significantly reduced the ocular pain and discomfort immediately after excimer PRK without any clinically significant complications or adverse effects.

The treatment of pain following excimer laser photorefractive keratectomy: additive effect of local anesthetic drops, topical diclofenac, and bandage soft contact.

BACKGROUND AND OBJECTIVE: Post-operative pain is a transient but undesirable side effect of photorefractive keratectomy (PRK). Pain control after excimer laser PRK was assessed in 112 eyes that were divided into 6 pain management groups. PATIENTS AND METHODS: "Pain at its worst" was measured using a visual analog scale. The groups are arranged in order, Group 6 having experienced the most effective relief of pain and Group 1 the least relief of pain: 1) Topical amethocaine/tetracaine, 2) Topical amethocaine/tetracaine plus bandage contact lens, 3) Topical diclofenac, 4) Topical diclofenac plus bandage contact lens, 5) Topical amethocaine/tetracaine plus diclofenac, and 6) Topical amethocaine/tetracaine, diclofenac plus bandage contact lens. All patients were given 10 tablets of co-dydramol (10 mg dihydrocodeine and 500 mg paracetamol per tablet). They were to be used every 4 hours, but patients were specifically instructed not to take the tablets unless the topical pain management was inadequate for their needs. RESULTS AND CONCLUSION: Group 6 was dramatically better than any other group. In fact, 31% of Group 6 patients had no pain whatsoever. Removing any one of the 3 pain management tools resulted in much less pain control. Day 1 pain was also much more effectively controlled by the Group 6 management compared with those of the other groups. Group 6 patients took fewer co-dydramol tablets than any of the other groups. In addition, Group 6 scored best n several other areas that were studied: a) Day 1 light sensitivity; b) Day 1 tearing; c) Day 1 drowsiness; and d) number of hours slept on the first night. The epithelium healed in all patients but one Group 5 and one Group 6 patient had an epithelial defect for longer than 7 days. There was no instance of infectious keratitis, nor was there an instance of the sterile keratitis that has been associated with the use of topical non-steroidal anti-inflammatory drops.

Removal of epithelium and scraping the underlying stroma as treatment for photorefractive keratectomy overcorrection or undercorrection of myopia.

BACKGROUND AND OBJECTIVE: A minority of patients who undergo excimer laser photorefractive keratectomy are overcorrected to the extent that they are symptomatic; they tend to be "poor healers" with little post-excimer subepithelial haze and a thinned epithelial layer. The reverse situation can also occur where "aggressive healing" results in undercorrection, excessive haze and a thickened epithelial layer. PATIENTS AND METHODS: Overcorrection was treated in 19 eyes by removal of the corneal epithelium overlying the treated cornea with a disposable number 15 scalpel blade under topical anesthesia at the slit lamp. The exposed stroma was gently abraded with the blade in order to create inflammation and the laying down of tissue to partially resteepen the cornea. Eight eyes with undercorrection had "hyperplastic epithelium" removed with the number 15 blade. The intention was to abrade underlying subepithelial haze only if it was felt that a plaque of "haze" could be removed by so doing; in fact, no plaques were removed and it was difficult to remove the epithelium without associated trauma to the superficial stroma. RESULTS: The mean refraction of the overcorrected eyes was +2.77 diopters (D) compared with +0.68 D at 12 months post-scraping. This can be contrasted with -3.11 D prior to scraping, and -4.67 D at 12 months for the undercorrected eyes. The only difference that could be detected between the overcorrected and undercorrected eyes was that the mean pre-excimer refraction of the overcorrected patients was -5.68 D, whereas that of the undercorrected patients was -8.22 D. It was not possible to predict which overcorrected eyes would do well after scraping. CONCLUSION: Scraping is a very effective treatment of overcorrection after photorefractive keratectomy. Scraping as a treatment of undercorrection should not be undertaken.

Treatment of astigmatism associated with myopia or hyperopia with the holmium laser: second year follow-up.

BACKGROUND AND OBJECTIVE: In 1993, the Summit Technology apogee system for treating astigmatism was not available, so (to avoid the deep cuts of astigmatic keratotomy) the Summit Holmium: YAG laser was used to treat astigmatism associated with myopia; an excimer laser photorefractive keratectomy was to be performed when the keratometry readings had stabilized. The holmium:YAG laser also was utilized to concurrently treat hyperopia and astigmatism. PATIENTS AND METHODS: For myopic astigmatism, four holmium spots were administered, two on either side of the optical zone. An optical zone of 6.5 mm was used for keratometric astigmatism of 4.00 diopters (D) or greater; 7.0 mm for 3.00 to 3.90 D; 7.5 mm for 1.50 to 2.90 D. For hyperopic astigmatism, two extra spots were placed in the inner treatment ring, one on either side of the flattest meridian for 1.50 to 2.90 D of keratometric astigmatism. By omitting the outer ring treatments in the steeper meridian and using four extra spots, two on either side of the flattest meridian in the inner ring, 3.00 D or more was treated. RESULTS: Thirty-one myopic eyes were treated; five were lost to follow-up; 12 have subsequently had a photoastigmatic refractive keratectomy (PARK); six have had a PRK; eight had had no further procedures. Seven eyes now have 18 months of follow-up or more (and have not had a PARK); the four successes are presented in detail and it appears that their keratometry readings are nearly stable. CONCLUSION: Four of 7 (57%) myopic eyes, which had holmium laser treatment of associated astigmatism, can be considered as successes after 18 months or more follow-up. Keratometry readings are nearly stable; further follow-up is required to determine if regression continues. The treatment of astigmatism simultaneously with hyperopia treatment with the holmium laser was not successful.

Holmium:YAG laser thermokeratoplasty to correct hyperopia: two years follow-up.

BACKGROUND AND OBJECTIVE: Treatment of hyperopia is more of a challenge than PRK but the development of the holmium:YAG laser has provided a more controlled way of carrying out laser thermokeratoplasty (LTK). PATIENTS AND METHODS: Twenty two eyes with hyperopia were treated with a Summit Technology OmniMed holmium laser by placing two rings of eight laser spots at 6.5 and 9 mm (centred on the visual axis) to produce a 4.00 diopters (D) correction. RESULTS: An average +2.10 D refractive correction was achieved in the 17 eyes with no induced astigmatism with an accuracy of 25% within 1.00 D, 60% within 2.00 D and 100% within 3.00 D. However, significant astigmatism (+1.25 to +2.5 Dcyl) was produced in 23% of eyes from 6 months post-laser and these required astigmatic LTK correction. CONCLUSIONS: The overall results were disappointing in that there was an approximate 50% regression at two years post-LTK. However, the rate of regression was very slow at 24 months, and most patients remarked how well they could see in the first few months following the treatment.

Holmium: YAG laser to treat astigmatism associated with myopia or hyperopia.

The Summit Technology, Inc. (Waltham, Mass.) holmium:YAG laser was used to treat astigmatism in 31 myopic and 8 hyperopic eyes. There was slow but continuing regression of effect even 1 year after treatment. This regression was particularly seen in hyperopic astigmatism, larger amounts of myopic astigmatism, and younger patients. In some cases keratometry readings returned to their pretreatment values. Males and females had similar results. The mean myopic shift in 9 myopic astigmatism eyes at 9-month follow up was 1 D.

Treatment of myopic astigmatism with photorefractive keratectomy using an erodible mask.

The Summit Technology erodible mask treatment of astigmatism does not alter the keratometric astigmatism significantly, even though the refractive astigmatism appears to improve by about 50%. Myopia is satisfactorily treated with the erodible mask, but there is slightly more undercorrection compared to photorefractive keratectomy (PRK) using an expanding diaphragm. Increasing the minus power in ordering the mask cylinder improves the myopia result, but not the keratometric astigmatism result. The following factors do not influence the keratometric astigmatism result: 1) The type of astigmatism (with-, against-the-rule, or oblique); 2) The initial keratometry readings; and 3) The time from the commencement of epithelial removal to laser treatment.

The treatment of pain following photorefractive keratectomy.

The most effective management of the pain that follows excimer laser photorefractive keratectomy (PRK) appears to be the use of topical nonsteroidal anti-inflammatory agents. A bandage contact lens for 2 days after photorefractive keratectomy is additive to pain relief. The helpfulness of patching was not confirmed. Surprisingly, drops of local anesthetic were not an efficacious means of managing the pain. This was possibly because they were not used frequently enough. The findings showed trends, but were not statistically significant.

Photorefractive keratectomy for myopia: 6-month results in 95 eyes.

Ninety-five eyes of 91 patients with myopia from -1.00 to -6.00 D (mean -3.40 D, +/- 1.2) were treated with an ExciMed UV2OOLA 193-nanometer excimer laser (Summit Technology, Inc, Waltham, Mass) (with version 5.5 software) with a 5-millimeter ablation zone. At 6 months, 67 eyes (70%) were within +/- 0.50 D, 84 eyes (88%) were within +/- 1.00 D, and 94 eyes (99%) were within +/- 2.00 D. There was an average overcorrection of +0.25 D which had decreased to +0.18 D by 9 months. Best spectacle corrected visual acuity was 6/6 or better in 88 eyes (94%) and six eyes (6%) had a corrected visual acuity of 6/9. Fifty percent of eyes had slight astigmatism (mean 0.68 D, range 0.25 to 2.00 D) and this reduced to 0.33D (0.02 > p > 0.01) at 6 months.

Familial congenital corneal anaesthesia.

Congenital corneal anaesthesia is a cause of severe corneal ulceration and scarring in childhood. Although uncommon, it may be underdiagnosed when present as an isolated entity. Measures such as the use of elbow splints and tarsorrhaphy may be necessary to prevent visual loss. In rare instances, the condition may be inherited. A family is presented with autosomal dominant isolated congenital corneal anaesthesia, and the systemic associations and treatment of the condition are reviewed.

The effects of donor age and cause of death on corneal graft survival.

The Ontario Corneal Recipient Registry followed 299 recipients of 326 corneal transplants performed between October 1985 and October 1987. This report describes the joint effects of donor age and cause of death on subsequent graft survival in these procedures up to two years after surgery. Cox regression analysis established that grafts from donors dying of injury experienced half the risk of graft failure of those from donors dying of heart disease or other natural causes (P less than 0.05). Although donor age differed substantially between these causes of death, controlling for donor age did not alter the association. There were no statistically or clinically significant differences in graft survival associated with either donor age or recipient age. These results suggest that the health of the donor and the circumstances surrounding death may influence the quality of corneal tissue, and deserve more attention and detailed study.

An improved method for measuring human tear lysozyme concentration.

Previously described methods for measuring human tear lysozyme are fraught with shortcomings. A new method has been devised. Tear fluid was collected on Whatman filter paper discs. Each disc was placed in a tightly capped tube containing sodium phosphate buffer. Fluid from each tube was placed directly into a well of the lysozyme immunodiffusion plate. After the precipitation rings had reached maximum size, their diameters were measured. A linear standard curve was constructed, and lysozyme concentration was expressed as micrograms per milliliter. The tear lysozyme concentration was obtained from the standard curve and corrected for the assay dilution factor. The mean tear lysozyme concentration in 15 normal patients was 1.4 +/- 0.5 mg/mL. In ten patients with dry eyes, the mean was 0.7 +/- 0.5 mg/mL. The method used to collect, store, and transport tears is easily performed in the clinic and readily tolerated by patients. The technique of radial immunodiffusion is reliable and simple, compared with other assays.

Corneal wedge resection in rabbits.

Corneal wedge resection was performed on 30 albino rabbits. There was a significant increase in astigmatism produced when the width or length of the wedge was increased.

Experimental radial keratectomy in rabbits for the correction of aphakia.

The effect on central corneal curvature of radial keratectomy was examined. Ten rabbits had six equally spaced radial wedges removed from the cornea of one eye. Preoperative and serial postoperative keratometry readings were performed to follow the change in refractive power. The follow-up period was 3 months. Radial keratectomy produced an initial steepening of the central cornea, but this effect had disappeared by the end of the follow-up period. It is suggested that this could well have been because the 10/0 prolene sutures pulled through the rabbit cornea, which does not possess a Bowman's membrane.

Indomethacin v. dexamethasone in the suppression of corneal neovascularization.

A 7-0 silk suture was placed in one of the corneas of each of 18 albino rabbits as a vasogenic stimulus. Two drops of normal saline, a 10.3 mg/ml suspension of indomethacin or a 0.1% suspension of dexamethasone, allocated in double-masked fashion, were then instilled in the 18 eyes three times per day. There was a statistically significant difference (p less than 0.01) in the rate of neovascularization between the 6 control corneas and the 12 treated corneas but no significant difference in the rate or the quality of neovascularization between the 6 indomethacin-treated corneas and the 6 dexamethasone-treated corneas.

Fixation sutures in the implantation of a flexible anterior chamber intraocular lens. Use in the presence of a sector iridectomy.

A technique is described for the safe implantation of a flexible anterior chamber intraocular lens in the presence of a sector iridectomy. The lens is inserted diagonally and two 10-0 polypropylene fixation sutures are used to attach one of the loops to the inner aspect of the corneal wound.