Journal List > J Korean Ophthalmol Soc > v.53(9) > 1009159

Kim and Lee: Comparison of Permanent Amniotic Membrane Transplantation and Temporary Amniotic Membrane Patch after Primary Pterygium Excision



To compare the clinical results, recurrence rates, and recurrence-related risk factors of permanent amniotic membrane transplantation (PAMT, group 1) and temporary amniotic membrane patch (TAMP, group 2) after excision of primary pterygium.


Recurrence grades were evaluated for 66 eyes (T1, T2, and T3; 0, 32, and 34 eyes, respectively) in group 1 and 73 eyes (T1, T2, and T3; 2, 42, and 29 eyes, respectively) in group 2. Surgical results were classified into surgical success (G0 or G1), conjunctival recurrence (G2), and corneal recurrence (G3). Recurrence rates were analyzed based on gender, age, Tan's preoperative grading system, horizontal and vertical length of the preoperative pterygium, the corneal involvement size of the preoperative pterygium, and epithelial healing time.


In the postoperative grading, 3 eyes (4.5%) and 1 eye (1.5%) in group 1, and 4 eyes (5.5%) and 2 eyes (2.7%) in group 2 were graded as clinically recurrence-occurred G2 and G3, respectively. There was no statistically significant difference in recurrence-occurred G2 and G3 cases between the two groups (p = 0.62). No risk factors of clinically significant G2 and G3 recurrence were identified in either group by Cox proportional hazards survival regression analysis.


The results of the present study suggest that PAMT tends to lower the recurrence rate compared to TAMP because the PAMT group had more T3 eyes than the TAMP group, although the two groups showed no statistically significant difference in clinically significant recurrence after pterygium excision.

Figures and Tables

Figure 1
Preoperative grades for primary pterygium before surgery. T1 (atrophic pterygium): Episcleral vessels unobscured. T2 (intermediate pterygium): Episcleral vessels partially obscured. T3 (fleshy pterygium): Episcleral vessels totally obscured.
Figure 2
Postoperative grades after excision of primary pterygium. G0 (grade 0) indicates a normal appearance of the operated site. G1 (grade 1) indicates the presence of some fine episcleral vessels, but without any fibrous tissue in the excised area extending up to but not beyond the limbus. G2 (grade 2; conjunctival recurrence) indicates the presence of additional fibrous tissues in the excised area without invading the cornea. G3 (grade 3; corneal recurrence) represents a true recurrence with a fibrovascular tissue invading the cornea.
Figure 3
Pterygium size on M-view system with a mathematical formula of quadrangle. (A) Vp = vertical distance (pixel); Hp = horizontal distance (pixel); θ = angle between V & H; D = corneal diameter (mm). (B) A mathematical formula of quadrangle.
Figure 4
Surgical procedures of pterygium excision with permanent amniotic membrane transplantation and temporary amniotic membrane patch. (A) The pterygium body and head was undermined and removed by blunt dissection. (B) The corneal defect area was shaved of any residual tissue with a Beaver blade and a diamond burr. (C, D) At the end of tissue excision, the amniotic membrane was removed from the filter paper, and placed over the conjunctival defect with the basement membrane side up (PAMT) and basement membrane side down (TAMP). And the amniotic membrane was secured to the episclera and the excision edges of the normal conjunctiva with 10-0 nylon suture.
Figure 5
Incidence of each postoperative pterygium grades based on the preoperative pterygium grades. In group 1, there were clinically significant G 2 and G 3 recurrence-occurred eyes in T2 and T3 groups; 1 eye (3%; 1/32 eyes) of G3 recurrence was observed in T2 group; 3 eyes (9%; 3/34 eyes) of G2 recurrence were observed in T3 group. In group 2, no postoperative recurrence was observed in preoperative T1 group. But, there were clinically significant G2 and G3 recurrence-occurred eyes in T2 and T3 groups; 2 eyes (4.8%; 2/42 eyes) of G3 recurrence were observed in T2 group; 4 eyes (13.8%; 4/29 eyes) of G2 recurrence were observed in T3 group.
Figure 6
Kaplan-Meier survival analysis showing the cumulative proportion without recurrence following the permanent amniotic membrane transplantation and temporary amniotic membrane patch with the excision of primary pterygium. This survival curve indicates that the estimated recurrence-free (G0 & G1) rate at postoperative 24 months were 88% in group 1 and 83% in group 2. No statistical differences were found between two groups (p = 0.205, log rank test).
Table 1
Demographic and clinical data of patients

Values are presented as number or mean ± SD.

*χ2-test; Student t-test.

Table 2
Preoperative size of pterygium

*Student t-test.

Table 3
Surgical outcomes of permanent amniotic membrane transplantation and temporary amniotic membrane patch after excision of primary pterygium

IOP = intraocular pressure.

*Fisher's exact test; χ2-test.

Table 4
Comparison of characteristics of the non-recurrent cases and the recurrent cases between two groups

Values are presented as number or mean ± SD.

*Student t-test; χ2-test; Fisher's exact test; §Linear by linear association.

Table 5
Risk factors influencing a recurrence of pterygium (G2 + G3) after surgery in relation to preoperative parameter

*p-value from the Cox proportional hazards survival regression analysis.

Table 6
Recurrence rates of amniotic membrane transplantation after excision of primary pterygium in recent reports

AMT = amniotic membrane transplantation; BM = basement membrane.

*Final appearance was graded according to the grading system (G0 to G3) reported by Prabhasawat et al,7 and overall recurrence rate was defined as G2 and G3; Intraoperatively, local triamcinolone acetonide injections (10 to 16 mg in total) were given along the edges of the excised conjunctiva at the end of tissue excision; The recurrence rate of the study was evaluated at postoperative 6 months.


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