A comparative study of preoperative and postoperative changes in corneal astigmatism after pterygium excision by different techniques

Purpose: To study the changes in corneal astigmatism before and after pterygium excision as well as with differences between various surgical techniques (bare sclera, conjunctival autograft, amniotic membrane graft). Methods: The study population included 71 patients with primary pterygium who underwent surgery. The surgical techniques used differed among the study population. All the patients were preoperatively assessed for visual acuity, anterior and posterior segments, autorefraction, and autokeratometry. After surgery, the patients were assessed for visual acuity, autorefraction, and autokeratometry on day 5, 1 month, and 3 months and the results were analyzed. Paired and unpaired t-tests were used to compare the variables. The probability level of 0.05 was considered as statistically significant. Results: The reduction in the mean preoperative astigmatism of 3.47 ± 1.74 Diopters (D) to 1.10 ± 0.78 D 3 months after surgery was statistically significant (P < 0.0001). Bare sclera, conjunctival autograft, and amniotic membrane graft techniques exhibited changes in astigmatism amounting to 1.85 ± 0.88 D, 2.55 ± 1.26 D, and 2.67 ± 1.44 D, respectively. Pterygium excision surgeries using amniotic membrane graft and conjunctival autograft techniques were more effective than pterygium excision surgery using bare sclera technique in reducing astigmatism. Conclusion: Pterygium excision results in significant reduction in astigmatism which leads to improvement in visual acuity. Amniotic membrane graft and conjunctival autograft are better surgical techniques than bare sclera as far as reducing astigmatism is concerned.

An overview of management of pterygium in Nigeria / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To review the management of pterygium in Nigeria.METHODS: The medical records of patients who had pterygium excisions over a four year period (January 1999-December 2002) were reviewed. These patients were seen at University of Nigeria Teaching Hospital and Ebrans Clinic both in Enugu, Nigeria. The analysis of patients' bio-data, clinical presentation, surgical management and post-operative complications were carried out using EPI-INFO version 6.1. Three surgical techniques were employed: bare sclera procedure only (60 eyes); bare sclera with adjuvant 5-fluorouracil (42 eyes)and bare sclera with mitomycin-C, MMC, (22 eyes).RESULTS: One hundred and twenty-four eyes of 72 patients had pterygium excisions and were followed up for a least one year post-operatively. There were 41 males (56.9%) and 31 females (43.1%) giving a male to female rario of 1 :0.8. The mean age was 42.8 years while the range was 20-69 years. Recurrence was highest is stage Ⅲ (55.6%) and lowest in stage Ⅰ (22.2%). Concerning the 3surgical techniques, the recurrence rates were 65.0%, 52%and L3.6% respectively.CONCLUSION: In the management of pterygium in a developing country, early excision with use of intraoperative MMC is advocated. It is safe, affordable, technically easier and less invasive.

A Comparative Study of Recurrence Rate in Bilateral Pterygium Surgery: Conjunctival Autograft Transplantation Versus Bare Scleral Techinque

PURPOSE: When the patients with both recurrent and primary pterygia, We performed conjunctival autograft transplantation for recurrent pterygium and bare sclera technique for primary pteygium. We then compared the recurrence of each case in order to find out the usefulness of each surgery and effective mothod of surgery. METHODS: We performed follow-up on 26 eyes of 13 patients for 14 months (mean); 8 patients (16 eyes) were female, and 5 patients (10 eyes) male. The mean age of the patients was 49.5 years ranging from 37 to 63. In the operation, all patients received with 0.02% Mitomycin C for 1 minute. RESULTS: Pterygium recurred in 3 of 13 eyes which underwent bare sclera technigue, and did not recur in 13 eyes undergoing conjunctival autograft transplantation, but there was no significant difference because of a small number of study cases (P=0.07). We found postoperative complications such as corneal fila-ment and conjunctival granuloma in the case of bare sclera technique; but none in conjunctival autograft transplantation. CONCLUSIONS: We recommend a conjunctival autograft transplantation with application of low concen-tration of Mitomycin C as a safe and effective method for recurrent pterygium or pterygium with high recurrence rate.

Pterygium Surgery Using Dermabrader

The aim of this study was to evaluate safety and effectiveness of dermabrader to smooth the wound bed in pterygium surgery. A total dof 69 eyes of 62 patients were divided into two groups according to surgical method. 33 eyes of 29 patients who underwent pterygium surgery with bare-sclera technique and smoothing of the wound bed using dermabrader were included in group 1 and 36 eyes of 33 patients with bare aclera technique only were included in group 2. Postoperatively, the eyes were medically treated with topical mitomycin C(0.02%) two times per day for 5 days in both groups. The mean follow up visit was 12.1+/-2.89 months(range: 9-15months). Recurrence developed in 3(9.1%) of 33 eyes in group 1, while in 12(33.3%) of 36 eyes in group 2. This difference was statistically significant(p<0.05). This result suggests that the excision of pterygium using the bare-sclera technique, smoothing of the wound bed using dermabrader and low dose topical mitomycin C(0.02%) eye drops is a safe and effective method with a low recurrence rate.

Postoperative Recurrence Rate of Scleral Fixation Technique and Bare Scleral Technique in Primary Pterygium Operation

Pterygium is a common surgical ocular disease which recurs frequently postoperatively. Numerous different techniques have been developed for the successful surgical treatment of pterygium. It was theorized that the pterygium recurrence after surgery would be prevented if scar tissue is formed on the bare sclera and if the corneal epithelium heals before the conjunctival epithelium reaches the limbus. We compared the recurrence rate of pterygium and complications after bare sclera technique with those after scleral fixation technique by which remaining conjunctiva was anchored tightly to the adjacent sclera with sutures. In the first group, 94 patients (103 eyes) operated by scleral fixation technique were composed of 45 male and 49 female. Their mean age was 57.2+/-9.7 years and mean follow-up period was 12.50+/-2.53 months. In the second group, 96 patients(101 eyes) operated by bare sclera technique were composed of 47 male and 49 female. Their mean age was 56.3+/-9.2 years and mean follow-up period was 12.12+/-2.41 months. The recurrence rate was 9.7%(10 eyes) in scleral fixation technique group and 32.7%(33 eyes) in bare sclera technique group. This difference was statistically significant(p<0.05). A case of postoperative scleromalacia was observed in the former group. The scleral fixation technique (as modified bare sclera technique) seems to be more effective for reducing postoperative recurrence of primary pterygium than simple bare sclera technique.

A Clinical Study of the Recurrence in Primary Pterygia

We made the clinical evaluation of the 110 primary pterygia which were excised according to D'ombrain bare sclera method and modified Bangerter method at Chunchon Sacred Heart Hospital from May of 1985 to April of 1987. The followup period ranged from 3 months to 12 months(average: 6 months). The results were as follows: 1. The total recurrence rate was 7.3%. 2. The bilaterality in recurrent group was 62.5%, whereas was 34.3% in nonrecurrent group(p<0.05). 3. The number of vessels(from the base of pterygium toward apex) in recurrent group was 27-35(average: 30.6 +/- 2.6), whereas was 8-32(average: 20.5 +/- 6.1) in non-recurrent group(p<0.05). 4. The incidence of the previous recurrent history of the other eye in recurrent group was 37.5%, whereas was 3.9% in non-recurrent group(p<0.05). 5. The recurrence rate in modified Bangerter method group was 1.6%, whereas was 15.2% in D'ombrain bare sclera method group(p<0.05) and the modified Bangerter method group gave very good esthetic results.

Re-epithelialization of the Conjunctiva After Conjunctival Excision in the Rabbits

Bare sclera technique for pterygium is used frequently because of its lower recurrence rate than those of other techniques. Various factors may influence reepithelialization of the bare sclera and the corneal defects. We excised various sizes of conjunctiva and abraded corneal epithelium in rabbits, and then studied at various intervals the pattern and the rate of their reepithelialization over the bare sclera and the cornea along with histologic findings, and the effect of 0.04 % mitomycin eyedrops on reepithelialization. We obtained the following results. 1. The bare sclera was epithelialized completely by the 7th or 8th day postoperatively, when the conjunctiva was serially excised, ranging from 3 X 3 mm to 6 X 6 mm in size. The rate of reepithelialization between the groups was not statistically significant(p>0.05). 2. The defect of the cornea was epithelialized by the 3rd day postoperatively in all experimental groups, and the reepithelialization rate between the groups was not statistically significant(p>0.05). 3. Reepithelialization over the bare sclera progressed posteriorly from the limbus, however, in the case of the cornea, epithelialization progressed from the margin of the defect to the limbus. 4. 0.04% mitomycin eyedrops did not have any effect on epithelialization over the bare sclera and the corneal defect.

Re-epithelialization of the Conjunctiva After Conjunctival Excision in the Rabbits

Bare sclera technique for pterygium is used frequently because of its lower recurrence rate than those of other techniques. Various factors may influence reepithelialization of the bare sclera and the corneal defects. We excised various sizes of conjunctiva and abraded corneal epithelium in rabbits, and then studied at various intervals the pattern and the rate of their reepithelialization over the bare sclera and the cornea along with histologic findings, and the effect of 0.04 % mitomycin eyedrops on reepithelialization. We obtained the following results. 1. The bare sclera was epithelialized completely by the 7th or 8th day postoperatively, when the conjunctiva was serially excised, ranging from 3 X 3 mm to 6 X 6 mm in size. The rate of reepithelialization between the groups was not statistically significant(p>0.05). 2. The defect of the cornea was epithelialized by the 3rd day postoperatively in all experimental groups, and the reepithelialization rate between the groups was not statistically significant(p>0.05). 3. Reepithelialization over the bare sclera progressed posteriorly from the limbus, however, in the case of the cornea, epithelialization progressed from the margin of the defect to the limbus. 4. 0.04% mitomycin eyedrops did not have any effect on epithelialization over the bare sclera and the corneal defect.