Quality of Refractive Error Care in Cambodia: An Unannounced Standardized Patient Study

Figures & data

Figure 1. Flow chart of unannounced standardised patient (USP) visits to optical services and dispensed spectacles.

Table 1. Percentage of dispensed spectacles and written prescriptions with optimal quality^a.

	Optimal quality (95% CI)^b
	Dispensed spectacles		Written prescriptions
	Frequency	%	Frequency	%
Battambang	6/16	37.5 (18.4–61.5)	9/16	56.3 (36.4–74.3)
Kampong Cham	5/15	33.3 (11.8–65.1)	5/15	33.3 (33.3–33.3)
Ta Keo	8/15	53.3 (31.5–74.0)	5/15	33.3 (33.3–33.3)
Phnom Penh	131/386	33.9 (29.6–38.6)	110/386	28.5 (23.8–33.7)
Siem Reap	13/64	20.3 (12.6–31.2)	35/64	54.7 (43.2–65.7)
Pooled (Unweighted)	163/496	32.9 (29.0–36.9)	164/496	33.1 (28.8–37.7)
Pooled (Weighted)		35.1 (29.9–40.7)		38.9 (34.4–43.6)

^aOptimal quality for written prescriptions only included the spherical, cylindrical and axis components.

^b95% CIs adjusted for intra-service correlation.

Table 2. Distribution of testing procedures and associations with spectacle quality.

	Visits (N = 615)	Dispensed spectacles (n = 496)
Testing procedure	Frequency (%)	Optimal quality frequency (%)	OR	[95% CI]	p-value^a
Focimetry performed
No/Did not take spectacles	342 (55.6)	77/22733 (33.9)	1.00
Yes	273 (44.4)	86/269 (32.0)	0.92	[0.65,1.30]	0.618
Distance VA checked at the beginning
No	254 (41.3)	65/206 (31.6)	1.00
Yes	361 (58.7)	98/290 (33.8)	1.11	[0.76,1.60]	0.590
VA checked with pinhole
No	537 (87.3)	145/421 (34.4)	1.00
Yes	78 (12.7)	18/75 (24.0)	0.60	[0.34,1.05]	0.073
Near VA checked at the beginning
No	388 (63.1)	95/297 (32.0)	1.00
Yes	227 (36.9)	68/199 (34.2)	1.10	[0.77,1.58]	0.591
Autorefraction performed
No	46 (7.5)	13/38 (34.2)	1.00
Yes	569(92.5)	150/458 (32.8)	0.94	[0.46,1.90]	0.586
Retinoscopy performed
No	575 (93.5)	155/458 (33.8)	1.00
Yes	40 (6.5)	8/38 (21.1)	0.52	[0.25,1.10]	0.087
Distance subjective refraction
Spherical/cylinder power not checked	318 (51.7)	68/221 (30.8)	1.00
Only spherical component tested	100 (16.3)	43/89 (49.4)	2.20	[1.31,3.68]	0.003
Only cylinder tested	5 (0.8)	0/5 (0.0)	NA
Sphere and cylinder tested	192 (31.2)	52/183 (28.4)	0.89	[0.57,1.41]	0.626
Near VA with distance lenses checked
No	432 (70.2)	107/337 (31.8)	1.00
Yes	183 (29.8)	55/159 (35.2)	1.17	[0.81,1.68]	0.400
Near subjective refraction performed
No	345 (56.1)	70/243 (28.8)	1.00
Yes	270 (43.9)	93/253 (36.8)	1.44	[1.00,2.07]	0.052
Clinician used a phoropter
No	257 (41.8)	71/235 (30.2)	1.00
Yes	137 (22.3)	45/127 (35.4)	1.27	[0.81,1.97]	0.293^b
No distance subjective refraction	221 (35.9)
Clinician used a trial frame
No	29 (4.7)	16/22 (72.7)	1.00
Yes	365 (59.3)	100/340 (29.4)	0.16	[0.07,0.36]	<0.001^b
No distance subjective refraction	221 (35.9)
Pupillary distance checked
No	525 (85.4)	129/410 (31.5)	1.00
Yes	90 (14.6)	34/86 (39.5)	1.42	[0.91,2.23]	0.122

^aAssessed via univariable logistic regression, accounting for within-optical service correlation.

^bExcludes 134 visits at which distance refraction was not performed, yet spectacles dispensed.

Table 3. Association between testing procedures and spectacle quality among spectacle types (Single-vision distance, n = 246; Single-vision near, n = 237).

	Single-vision distance				Single-vision near
	Optimal quality frequency (%)	Odds Ratio	[95% CI]	p-value^a	Optimal quality frequency (%)	Odds Ratio	[95% CI]	p-value^a
Refractive status at baseline
Emmetropic	-	-	-	-	71/165 (43.0)	1.00
Astigmatism only/myopic astigmatism	10/119 (8.4)	1.00			-	-	-	-
Myopia only	11/14 (78.6)	101.48	[7.18,1434.88]	0.001	-	-	-	-
Hyperopia only	49/113 (43.4)	19.39	[7.44,50.48]	<0.001	9/72 (12.5)	.17	0[.07,.40]	<0.001
Focimetry performed
No/USP did not take spectacles	16/65 (24.6)	1.00			48/149 (32.2)	1.00
Yes	54/181 (29.8)	5.56	[2.25,13.75]	<0.001	32/88 (36.4)	1.10	[0.62,1.94]	0.738
Autorefraction performed
No	8/15 (53.3)	1.00			4/22 (18.2)	1.00
Yes	62/231 (26.8)	0.58	[0.07, 5.06]	0.624	76/215 (35.3)	1.39	[0.30,6.43]	0.674
Distance VA checked at beginning
No	29/111 (26.1)	1.00			-	-	-	-
Yes	41/135 (30.4)	0.82	[0.384,1.77]	0.610	-	-	-	-
Distance subjective refraction
Spherical component not tested*	14/76 (18.4)	1.00			45/141 (31.9)	1.00
Only spherical component tested	18/32 (56.3)	2.05	[0.59,7.08]	0.255	22/52 (42.3)	1.66	[0.77,3.55]	0.195
Sphere & cylinder tested	38/138 (27.5)	1.87	[0.73,4.81]	0.196	13/44 (29.5)	1.57	[0.75,3.31]	0.233
Near VA tested with distance lenses
No	-	-	-	-	3/8 (37.5)	1.00
Yes	-	-	-	-	77/229 (33.6)	.94	[.50,1.76]	0.848
Near subjective refraction performed
No	-	-	-	-	66/203 (32.5)	1.00
Yes	-	-	-	-	14/34 (41.2)	.83	[0.17,4.04]	0.817
Pupillary distance checked
No	51/195 (26.2)	1.00			66/203 (32.5)	1.00
Yes	19/51 (37.3)	1.95	[0.93,4.09]	0.076	14/34 (41.2)	1.80	[0.85,3.83]	0.126

95% CI = 95% confidence interval.

^aEach multivariable logistic regression model was assessed with robust standard errors to account for intra-service correlation.

^bIncludes 2 visits where only the cylindrical component was checked during distance subjective refraction.

Data availability statement

Data are available upon reasonable request.