Comparison of the Effects of Patterned and Conventional Panretinal Photocoagulation on Diabetic Retinopathy

Ji-Wook Yang; Young-Chun Lee

doi:10.3341/jkos.2010.51.12.1590

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Yang and Lee: Comparison of the Effects of Patterned and Conventional Panretinal Photocoagulation on Diabetic Retinopathy

Original Article

J Korean Ophthalmol Soc 2010;51(12):1590-1597.

Published online: 7 September 2010

DOI: https://doi.org/10.3341/jkos.2010.51.12.1590

Comparison of the Effects of Patterned and Conventional Panretinal Photocoagulation on Diabetic Retinopathy

Ji-Wook Yang, MD, Young-Chun Lee, MD, PhD

Department of Ophthalmology and Visual Science, The Catholic University of Korea School of Medicine, Seoul, Korea

Address reprint requests to Young-Chun Lee, MD, PhD Department of Ophthalmology, Uijeongbu St. Mary's Hospital #65-1 Geumo-dong, Uijeongbu 480-717, Korea Tel: 82-31-820-3022, Fax: 82-31-847-3418, E-mail: yclee@cmcnu.or.kr

Received 23 February 2010 Accepted 29 October 2010

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To compare the therapeutic effects and complications after panretinal photocoagulation (PRP) and discomforts of patients using patterned PRP versus conventional PRP for diabetic retinopathy.

Methods

Eighty patients who required PRP due to diabetic retinopathy were enrolled in a prospective randomized controlled study. The patients were randomly divided into two groups: a patterned PRP group in which PRP was performed with a short laser exposure time (0.02 seconds) and a conventional PRP group with a long exposure time (0.2 seconds). At the 1-year follow-up visit, the progressions of diabetic retinopathy, best-corrected visual acuity, and central macular thickness were evaluated. All patients were questioned about the grade of pain during PRP. In addition, the complications after PRP were investigated.

Results

There were no statistical differences in clinical characteristics between both groups. The progression of diabetic retinopathy was not different in both groups at the 1-year follow-up visit. The best-corrected visual acuities at 1, 2, 4, and 8 weeks after PRP were decreased in both groups and, in the conventional PRP group, the decrements of visual acuity were greater than in the patterned PRP group. The increments of central macular thickness were also greater in the conventional PRP group than the patterned PRP group.

Conclusions

When patterned PRP is performed using a short laser exposure time, the efficacy in the treatment of diabetic retinopathy is similar to that of the conventional PRP using a longer laser exposure time. Moreover, patterned PRP is less painful, and fewer complications.

Keywords: Diabetic retinopathy, Laser exposure time, Patterned panretinal photocoagulation

References

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Figure 1.

Changes in best-corrected visual acuities (logarithm of the minimal angle of resolution) after panretinal photocoagulation. The best-corrected visual acuities at post-laser 1, 2, 4, and 8 weeks decreased in patterned PRP^* group and conventional PRP^† group, and in conventional PRP group the decrements of visual acuities were greater (p = 0.01, repeated measures ANOVA).^* patterned PRP group = patients who received patterned panretinal photocoagulation using 0.02 second laser exposure time in a single treatment session; ^† conventional PRP group = patients who received panretinal photocoagulation using 0.2 second laser exposure time in three treatment sessions; BCVA = best-corrected visual acuity.

Figure 2.

Changes in central macular thickness after panretinal photocoagulation. The central macular thickness increased in patterned PRP group and conventional PRP group, and in conventional PRP group the increments of central macular thickness were greater (p = 0.01, repeated measures ANOVA). CMT = central macular thickness.

Table 1.

Clinical characteristics of the patients in both groups

	Patterned PRP Group	Conventional PRP Group	p value
Age (yr)	60.03 ± 13.66	58.78 ± 11.30	0.657^∏
Sex	Male: Female = 20:20	Male: Female = 19:21	0.826^#
Duration of DM^* (yr)	9.28 ± 8.72	12.12 ± 6.83	0.216^∏
Severity of diabetic retinopathy	Severe NPDR^†: 40/78	35/77	0.505^#
	Very severe NPDR: 21/78	17/77	0.684^#
	Early PDR^‡: 11/78	15/77	0.583^#
	High risk PDR: 6/78	10/77	0.648^#
HBP^§	55% (22/40)	50% (20/40)	0.508^#
HbA1C	8.75 ± 1.92	8.36 ± 1.53	0.422^∏
Blood urea nitrogen (mg/dL)	18.42 ± 6.30	16.87 ± 4.95	0.308^∏
Creatinine (mg/dL)	1.13 ± 0.83	1.07 ± 0.46	0.585^∏
Total cholesterol (mg/dL)	191.11 ± 38.97	188.39 ± 47.47	0.835^∏

^* DM = diabetes mellitus

^† NPDR = nonproliferative diabetic retinopathy

^‡ PDR = proliferative diabetic retinopathy

^§ HBP = hypertension

^∏ Student t test

^# Chi-square test.

Table 2.

Comparisons of laser parameters and pain in both groups

	Patterned PRP Group	Conventional PRP Group	p value^*
Laser power (mW)	468.83 ± 106.08	307.10 ± 12.18	0.01
Fluence (J/cm²)	26.21 ± 7.29	189.40 ± 45.33	0.01
Laser spot number	1,728.90 ± 324.39	1,624.92 ± 511.92	0.205
Pain	2.18 ± 0.97	5.88 ± 1.06	0.02

^* Student t test.

Table 3.

Progression of diabetic retinopathy in one year follow-up after panretinal photocoagulation in both groups

	Progression of DMR^*	Number of eyes (%)		p value^∏
	Progression of DMR^*	Patterned PRP group	Conventional PRP Group	p value^∏
NPDR^‡	Number of progression to PDR^§	5/61 (8.2%)	7/52 (13.5%)	0.274
PDR	Number of complete NV^# regression	11/17 (65.7%)	17/25 (68%)	
	Number of partial NV regression	6/17 (35.3%)	8/25 (32%)	0.541
	Number of no NV regression	0/17 (0%)	0/25 (0%)	
	Number of vitrectomy	2/17 (11.8%)	3/25 (12%)	0.683

^* DMR =diabetic retinopathy

^† NPDR =nonproliferative diabetic retinopathy

^‡ PDR =proliferative retinopathy

^§ NV =new vessel

^∏ Fisher's exact test.

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