Comparison of keratometric readings with manual separation of lids and with wire speculum in children less than 5 years of age.

Dear Editor,

An important component for precise intraocular lens (IOL) power calculation is accurate keratometry (K) readings. Manual keratometer and IOL master have been widely used for this purpose.[123] But in young children and uncooperative adults, such instruments failed to solve the purpose. Portable handheld keratometers are preferred in such cases under general anesthesia (GA)/sedation.[1] To use such an instrument, eyes need to be forcibly opened using hands/speculum, which can be an important aspect leading to errors.

Jethani et al.[4] compared the K readings in children (age range 5–16 years) with manual separation of lids and wire speculum. They also measured the K values in awake period. They did not find any significant change in K values. Scleral rigidity is very less in small children, which may lead to significant variation of readings with such manipulations.[5] Hence, such a study needs to be replicated in smaller children.

We compared the K readings under GA prospectively using manual separation and wire speculum. Sample size was not calculated, considering this a pilot analytical study. From September 2021 to November 2021, all consecutive cases – 39 eyes of 21 patients (<5 years of age) – being operated for cataract surgery were included. We excluded children with corneal and scleral pathologies. All the readings were taken under GA, first by manual separation of lids and then by appropriate-sized wire speculum.

Table 1 shows the results and appropriate statistical analysis. We did not find significant difference between the K readings of eyes separated with the speculum and with hand. The correlation coefficient was also very strong (>0.95), although we observed that in two patients where the K readings were the lowest (<40 D) had 0.8 D steepening with the speculum. An important limitation of our study was that we could not measure the K readings in awake positions due to lack of cooperation.

Table 1

Biometric details of patients with analysis

Total patient	39 eyes of 21 patients
Mean age	2.59±1.4 years
Age group (months)	Eyes (n)
0-18	14
>18-36	16
>36	9
Mean K1 value, D (manual separation)	43.69±2.24
Mean K1 value, D (speculum)	43.74±2.11
P*	0.927
Interclass correlation coefficient**	0.966
Mean K2 value, D (manual separation)	45.10±2.41
Mean K2 value, D (speculum)	45.05±2.19
P*	0.912
Interclass correlation coefficient**	0.958
Mean axial length (mm)	20.9±1.86

ANOVA=analysis of variance. *Paired t-test, **ANOVA: two-factor ANOVA without replication data analysis

To conclude, manual separation of lids by hand or speculum gives comparable K results. Caution is required while interpreting in patients having lower K values.

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Conflicts of interest

There are no conflicts of interest.