Performance of Two Photoscreeners Enhanced by Protective Cases

Figures & data

Figure 1 Kaleidos enhanced housing for 2WIN photoscreening, with housing opened to allow manual control. (Parental permission given for use of all photographs).

Figure 2 GoCheck Kids iPhone 7 Plus with flash-concentrating case being used in a tent in Burma.

Table 1 Validation of Kaleidos and GoCheck Kids Compared to Age-Added 2013 Amblyopia Risk Factors and True Amblyopia

	x+	x–
s+	A	B
s–	C	D
si	E	F	n=162				2×2					i=r
2013 ARF	A	B	C	D	E	F	sens	spec	PPV	NPV	Y J	sens	spec	PPV	NPV	Y J
Kaleidos	55	19	11	61	2	14	83%	76%	74%	85%	60%	84%	65%	63%	85%	49%
GCK	40	13	25	78	3	3	62%	86%	75%	76%	47%	63%	83%	73%	76%	46%
G-read	47	30	18	61	3	3	72%	67%	61%	77%	39%	74%	65%	60%	77%	38%
Amblyopia	A	B	C	D	E	F	sens	spec	PPV	NPV	Y J	sens	spec	PPV	NPV	Y J
Kaleidos	33	41	2	70	1	15	94%	63%	45%	97%	57%	94%	56%	38%	97%	50%
GCK	31	23	4	98	1	5	89%	81%	57%	96%	70%	89%	78%	53%	96%	67%
G-read	28	49	8	71	1	5	78%	59%	36%	90%	37%	78%	57%	35%	90%	35%

Notes: Kaleidos is the Adaptica 2WIN infrared photoscreener in a protective case while GoCheck Kids is an iPhone 7 Plus in a flash-concentrating protective case with local interpretation (GCK) as well as central expert reading interpretation (G-read). A–D are values for screen “refer” (s+) and screen “pass” (s–) compared to confirmatory examination risk factors present (x+) and examination risk factors not present (x–). Values E and F are when the screening device was inconclusive or unable to deliver a definitive result (si). Examination outcomes are classified as actual “amblyopia” or amblyopia risk factors stratified by age defined by AAPOS in 2013 (2103+ ARF) with the older age triad expanded to include all subjects older than 48 months. Sensitivity (sens), specificity (spec), positive predictive value (PPV), negative predictive value (NPV) and Youden’s J (Y J) are presented regarding just the A–D conventional subset (“2×2”) as well as considering each inconclusive screening result (si) as if it were a refer (i=r).

Figure 3 ROC curve. Performance of GoCheck Kids iPhone 7 Plus with flash-concentrating case (GCK, circles) and 2WIN photoscreener in Kaleidos enhancing case (Kaleidos, squares) validated against the age-enhanced 2013 AAPOS uniform amblyopia risk factor (ARF) guidelines (solid bold lines) and amblyopia (fine, dashed lines).

Table 2 Correlations Between Kaleidos Refractions and Cycloplegic Examination

	Bland–Altman				Intraclass Correlation
	Mean Diff	Lower	Upper	St Diff	ICC	Low ICC	High ICC
GCK sphere	1.05	−2.34	4.45	1.73	0.66	0.41	0.79
GCK aniso	0.25	−1.21	1.71	0.74	0.62	0.46	0.73
GCK astig	0.33	−2.03	2.71	1.21	0.64	0.52	0.73
K sphere	0.41	−2.19	3.05	1.37	0.82	0.76	0.87
K aniso	0.06	−1.03	1.14	0.56	0.8	0.74	0.86
K astig	−0.15	−1.52	1.21	0.69	0.83	0.79	0.87
K-2WIN J0	−0.08	−0.76	0.6	0.35	0.47	0.38	0.55
K-2WIN J45	0	−0.5	0.5	0.25	0.57	0.49	0.64

Notes: GoCheck Kids with flash-concentrating case (GCK) and 2WIN photoscreener in Kaleidos case (K) comparing spherical equivalent (sphere), anisometropia (aniso) and cylinder (astig) against cycloplegic refraction. The Bland–Altman metrics include the mean difference (Mean Diff) with confidence limits and the standard deviation of the difference (St Diff). Correlations are demonstrated by intraclass correlation coefficients (ICC) with confidence limits. Kaleidos refractions were compared to cycloplegic refractions using the J0 (K-2WIN J0) and J45 (K-2WIN J45) vectors.

Figure 4 Kaleidos J0 vector analysis comparing Kaleidos refractions with cycloplegic retinoscopy.

Figure 5 J45 vector analysis comparing 2WIN photoscreening through Kaleidos protective case with uniform guidelines cycloplegic refraction.

Figure 6 Bland–Altman plot for J0 vectors comparing Kaleidos with retinoscopy.

Figure 7 Bland–Altman plot for J45 vectors comparing Kaleidos with retinoscopy.