Time to Keratometric Stability After Pterygium Excision and the Associated Factors: A Clinical Perspective

Figures & data

Table 1 Baseline Characteristics of Study Participants

Characteristics	Number of Eyes (%) (n=75)
Age (years)
0–40	11 (14.7)
41–60	38 (46.7)
> 60	26 (34.6)
Laterality
Right	40 (53.5)
Left	35 (46.7)
Grade of pterygium (atrophic/intermediate/fleshy)
One-headed (63 eyes)	18 (28.5)/34 (54.0)/11 (17.5)
Double-headed (9 eyes)
Nasal side	0/8 (88.9)/1 (11.1)
Temporal side	1 (11.1)/7 (77.8)/1 (11.1)
Size of pterygium from limbus to head (71 eyes)
≤ 3 mm	30 (42.3)
> 3 mm	41 (57.7)
Best corrected visual acuity
20/20 – 20/40	54 (72.0)
< 20/40 – 20/70	11 (14.7)
< 20/70 – 20/200	7 (9.3)
< 20/200	3 (4.0)
Type of astigmatism
With-the-rule	55 (73.3)
Against-the-rule	20 (26.7)
Surgical technique
Amniotic membrane graft	65 (86.7)
Conjunctival graft	6 (8.0)
Bare sclera	4 (5.3)

Figure 1 Cumulative percentage of eyes with corneal astigmatic stability after pterygium surgery.

Table 2 Factors Associated with Time to Stability of Corneal Astigmatism After Pterygium Surgery

Factors	HRCrude	95% CI^a	HRAdjusted	95% CI^b
Age (Ref: <40 years)
	χ^2=0.78, df=2, P=0.68
41–60 years	0.75	0.28, 2.05
> 60 years	0.61	0.21, 1.83
Grade of pterygium (Ref: grade 1: Atrophic)
	χ^2=1.38, df=2, P=0.50
Grade 2: Intermediate	1.76	0.65, 4.74
Grade 3: Fleshy	1.82	0.53, 6.28
Duration of pterygium (years)	1.00	0.95, 1.04
Length of pterygium from the limbus to the apex (≤ 3, > 3 mm)	0.39^c	0.18, 0.85	0.41^c	0.19, 0.89
Absolute pre-operative corneal astigmatism (diopters)	0.59^c	0.38, 0.92	0.69	0.39, 1.22
Absolute change of corneal astigmatism one month after surgery (diopters)	0.52^c	0.30, 0.93	0.75	0.38, 1.49

Notes: ^aUnivariate analysis. ^bMultivariate analysis with Cox regression model. ^cP<0.05.

Figure 2 Cumulative percentage of eyes with mean keratometric stability after pterygium surgery.

Table 3 Factors Associated with Time to Stability of Mean Keratometric Power After Pterygium Surgery

Factors	HRCrude	95% CI^a	HRAdjusted	95% CI^b
Age (Ref:<40 years)
	χ^2=4.14,df=2, P=0.13		χ^2=3.90,df=2, P=0.14
41–60	1.30	0.57, 2.96	1.16	0.50, 2.68
> 60	0.70	0.29, 1.72	0.63	0.25, 1.55
Grade of pterygia (Ref: grade 1: Atrophic)
	χ^2=0.16,df=2, P=0.93
Grade 2: Intermediate	0.88	0.47, 1.65
Grade 3: Fleshy	0.92	0.40, 2.11
Duration of pterygia	1.03 ^c	1.00, 1.06	1.03	0.99, 1.07
Length of pterygia from the limbus to the apex (≤ 3, > 3 mm)	1.05	0.60, 1.86	0.96	0.54, 1.70
Pre-operative mean corneal refraction (diopters)	1.09	0.93, 1.28
Absolute change of mean corneal refraction one month after surgery (diopters)	0.86	0.60, 1.22

Notes: ^aUnivariate analysis. ^bMultivariate analysis with Cox regression model. ^cP <0.05.