Ganglion cell complex and retinal nerve fiber layer thickness in predicting visual outcome in brain tumors after surgery

Table 1 Demographic data and clinical profile of study participants, n (%)/mean ± SD

		Male (n = 6)	Female (n = 29)	Total (n = 35)	P value
Age (years)		34.67 ± 10.58	35.24 ± 12.42	35.14 ± 11.98	0.92
Residence					0.85
Local		5 (83.33)	25 (86.21)	30 (85.71)
Regional		1 (16.67)	4 (13.79)	5 (14.29)
Socio-economic status					0.19
Upper		1 (16.67)	1 (3.45)	2 (5.71)
Upper middle		3 (50.00)	11 (37.93)	14 (40.00)
Lower middle		1 (16.67)	16 (55.17)	17 (48.57)
Upper lower		1 (16.67)	1 (3.45)	2 (5.71)
Occupation					< 0.01
Farmer		1 (16.67)	0 (0.00)	1 (2.86)
Homemaker		1 (16.67)	21 (72.41)	22 (62.86)
Student		2 (33.33)	7 (24.14)	9 (25.71)
Business		2 (33.33)	0 (0.00)	2 (5.71)
Teacher		0 (0.00)	1 (3.45)	1 (2.86)
Chief complaints					0.82
Headache	Yes	5 (83.33)	23 (79.31)	28 (80.00)
	No	1 (16.67)	6 (20.69)	7 (20.00)
Visual loss	Yes	4 (66.67)	24 (82.76)	28 (80.00)	0.37
	No	2 (33.33)	5 (17.24)	7 (20.00)
Others (hormonal disturbances)	Yes	5 (83.33)	22 (75.86)	27 (77.14)	0.69
	No	1 (16.67)	7 (24.14)	8 (22.86)

Table 2 Retinal nerve fiber layer thickness (microns) in various tumor categories, mean ± SD

Tumour category	Retinal nerve fiber layer preoperative	At discharge	After 1.5 months	After 3 months	After 6 months
Pituitary adenoma	79.7 ± 27.9	80.7 ± 27.8	81.2 ± 27.5	87.6 ± 27.6	83.3 ± 28.2
Craniopharyngioma	102.0 ± 36.8	89.6 ± 34.2	67.5 ± 19.2	65.6 ± 18.2	67.8 ± 19.5
Meningioma	59.4 ± 12.9	62.8 ± 12.4	63.7 ± 11.1	60.0 ± 8.9	61.2 ± 9.9
Others	99.6 ± 32.2	89.1 ± 34.0	87.4 ± 31.8	86.9 ± 30.9	75.7 ± 27.0

Table 3 Distribution of retinal nerve fiber layer and ganglion cell complex thickness at baseline and follow-up visits, mean ± SD

Retinal nerve fiber layer thickness (micron)	Pre-operative	At discharge	After 1.5 months	After 3 months	After 6 months
Superior	110.19 ± 60.94	107.16 ± 43.84	97.28 ± 31.19	97.38 ± 29.16	98.54 ± 31.98
Inferior	107.25 ± 53.04	102.84 ± 34.25	95.87 ± 32.16	93.58 ± 32.07	95.97 ± 31.04
Nasal	68.04 ± 31.85	65.79 ± 22.88	61.53 ± 16.13	60.78 ± 15.41	61.83 ± 16.58
Temporal	51.51 ± 19.25	50.72 ± 12.29	51.16 ± 12.1	51.38 ± 10.32	51.91 ± 9.97
Ganglion cell complex thickness (micron)	65.67 ± 14.85	64.85 ± 15.23	65.26 ± 13.69	65.43 ± 15.59	66.19 ± 15.62

Table 4 Proportion of eyes with retinal nerve fiber layer and ganglion cell complex thinning, before and after surgery, n (%)

			Preoperative			P value
			Normal	Thinning	Total
Postoperative	RNFL (superior)	Normal	35 (50.7)	4 (5.8)	39 (56.5)	0.25
		Thinning	8 (11.6)	22 (31.9)	30 (43.5)
		Total	43 (62.3)	26 (37.7)	69 (100)
	RNFL (inferior)	Normal	33 (47.8)	3 (4.3)	36 (52.2)	< 0.05
		Thinning	12 (17.4)	21 (30.4)	33 (47.8)
		Total	45 (65.2)	24 (34.8)	69 (100)
	RNFL (nasal)	Normal	42 (60.9)	6 (8.7)	48 (69.6)	0.22
		Thinning	11 (15.9)	10 (14.5)	21 (30.4)
		Total	53 (76.8)	16 (23.2)	69 (100)
	RNFL (temporal)	Normal	32 (46.4)	16 (23.2)	48 (69.6)	< 0.05
		Thinning	6 (8.7)	15 (21.7)	21 (30.4)
		Total	38 (55.1)	31 (44.9)	69 (100)
	GCC	Normal	20 (29.0)	12 (17.4)	32 (46.4)	0.09
		Thinning	5 (7.2)	32 (46.4)	37 (53.6)
		Total	25 (36.2)	44 (63.8)	69 (100)

GCC: Ganglion cell complex; RNFL: Retinal nerve fiber layer.

Table 5 Association of visual impairment with retinal nerve fiber layer and ganglion cell complex thickness, at baseline and final follow-up, mean ± SD

		Mild visual impairment (6/6-6/18)	Moderate impairment (6/18-6/36)	Severe impairment to blind (6/36-3/60)	P value
Preoperative
RNFL thickness in micron	Superior	128.06 ± 65.91	98.17 ± 24.37	66.06 ± 18.34	< 0.01
	Inferior	123.41 ± 54.42	103.67 ± 24.42	64.76 ± 27.67	< 0.01
	Nasal	74.96 ± 34.56	59.67 ± 18.14	52.29 ± 20.57	< 0.05
	Temporal	55.89 ± 21.23	42.83 ± 7.81	42.7 ± 11.08	< 0.05
Mean GCC thickness in micron		70.5 ± 13.6	58 ± 10.02	55.29 ± 13.51	< 0.01
Postoperative (six-month follow-up)
RNFL thickness in micron	Superior	105.98 ± 29.84	95.25 ± 28.06	63.18 ± 17.95	< 0.01
	Inferior	102.61 ± 27.51	101 ± 38.84	61.54 ± 23.1	< 0.01
	Nasal	63.2 ± 15.28	69.75 ± 9.18	52.18 ± 21.64	0.08
	Temporal	53.2 ± 9.19	46.5 ± 8.18	47.54 ± 12.89	0.12
Mean GCC thickness in micron		69.9 ± 12.67	67.25 ± 16.98	47.54 ± 16.26	< 0.01

GCC: Ganglion cell complex; RNFL: Retinal nerve fiber layer.

Table 6 Univariate analysis of factors predictive of blindness

Variables		Preoperative		Final postoperative
		Cor (95%CI)	P value	Cor (95%CI)	P value
Age		0.99 (0.93-1.06)	0.915	1.00 (0.92-1.08)	0.991
Duration of symptoms		0.96 (0.86-1.06)	0.45	0.98 (0.89-1.08)	0.764
Preoperative mean RNFL thickness	Superior	0.95 (0.92-0.98)	< 0.01	0.96 (0.94-0.99)	< 0.01
	Inferior	0.96 (0.93-0.98)	< 0.01	0.96 (0.94-0.98)	< 0.01
	Nasal	0.97 (0.93-1.00)	0.06	0.98 (0.95-1.01)	0.273
	Temporal	0.93 (0.87-0.99)	< 0.05	0.95 (0.88-1.01)	0.11
Preoperative mean GCC thickness		0.95 (0.91-0.99)	< 0.05	0.95 (0.91-0.99)	< 0.05
Tumor volume		1.00 (0.99-1.00)	0.128	1.00 (0.99-1.00)	0.09
Duration of surgery		1.61 (0.95-2.75)	0.078	1.57 (0.83-2.99)	0.166
Surgical approach		3.23 (0.55-18.96)	0.194	4 (0.39-40.1)	0.239

GCC: Ganglion cell complex; RNFL: Retinal nerve fiber layer.