Table 3.

Comparison of Retinal Layer Thickness

	Control			Post-PRP PDR
Thickness (µm)	Baseline	Follow-up	P value	Baseline	Follow-up	P value	P value*
Fovea
NFL	18.84 ± 1.15	17.65 ± 0.68	0.003	20.25 ± 4.79	20.88 ± 4.98	0.502	0.006
GC/IPL	39.57 ± 13.52	39.94 ± 13.43	0.477	40.28 ± 11.34	36.70 ± 13.22	0.018	0.515
INL	23.39 ± 6.84	23.39 ± 7.69	0.635	29.20 ± 6.24	30.12 ± 11.57	0.606	0.092
OP/ONL	139.55 ± 10.74	138.86 ± 9.22	0.386	141.24 ± 25.52	135.76 ± 28.06	0.072	0.642
IS/OS	38.39 ± 1.96	37.47 ± 1.55	0.075	32.80 ± 9.28	32.30 ± 9.41	0.139	0.006
RPE	31.03 ± 3.28	30.12 ± 4.18	0.075	28.58 ± 3.83	28.51 ± 3.75	0.911	0.273
Parafovea
NFL	27.66 ± 1.77	27.56 ± 1.80	0.722	33.87 ± 5.98	33.29 ± 5.66	0.445	<0.001
GC/IPL	93.67 ± 8.14	91.75 ± 7.08	0.013	86.79 ± 12.00	83.63 ± 12.89	0.005	0.062
INL	39.92 ± 3.86	39.79 ± 4.60	0.722	39.05 ± 5.87	38.97 ± 5.84	0.733	0.688
OP/ONL	118.28 ± 4.88	117.50 ± 4.93	0.033	123.60 ± 15.46	122.77 ± 14.46	0.592	0.134
IS/OS	33.31 ± 1.98	33.17 ± 2.03	0.657	30.30 ± 5.79	29.70 ± 6.02	0.088	0.026
RPE	30.66 ± 2.96	29.87 ± 3.03	0.155	26.63 ± 3.20	26.86 ± 3.22	0.783	0.015
Perifovea
NFL	41.46 ± 5.17	40.73 ± 5.08	0.213	52.17 ± 9.50	50.90 ± 9.63	0.200	<0.001
GC/IPL	64.05 ± 5.08	63.12 ± 4.67	0.182	67.12 ± 7.25	66.10 ± 7.15	0.322	0.222
INL	30.44 ± 2.53	30.19 ± 2.69	0.328	31.40 ± 5.09	31.59 ± 5.39	0.884	0.895
OP/ONL	95.96 ± 6.85	95.24 ± 6.80	0.033	103.37 ± 10.71	103.84 ± 10.12	0.709	0.009
IS/OS	34.02 ± 2.96	34.10 ± 1.67	0.722	29.64 ± 4.85	29.16 ± 5.08	0.131	<0.001
RPE	27.46 ± 4.63	26.72 ± 3.83	0.374	25.48 ± 2.94	25.41 ± 4.08	0.783	0.384

INL, inner nuclear layer; OP/ONL, outer plexiform/outer nuclear layer; RPE, retinal pigmented epithelium.

Even after 5 years, diabetic patients treated with PRP still had pathologic changes in the NFL and IS/OS. They also showed progressive thinning of GC/IPL over time.

^*Compared the results at the follow-up visit between control and diabetic patients.