1.  College of Ophthalmology & Allied Vision Sciences (COAVS), KEMU, Lahore, Pakistan; Shahzadanwar42@gmail.com

*Corresponding author: Shahzadanwar42@gmail.com

Keywords: auto-refraction, retinoscopy, cycloplegic, subjective, objective, dark room

1. INTRODUCTION

Refractive errors are determined by two methods, one is subjective and other is objective. For non-cooperative children and adults objective technique is used. To find out the correct refractive status subjective technique is used. Accurate correction of refractive errors is too much necessary in too young children with high hyperopia, strabismus and amblyopia [1]. Refractive power of the eye is the effect of lens and cornea to focus the Light rays. Accommodation force is the change of pitch of the curvature of lens for the change of light. Cycloplegia delays the accommodative power by inhibition the action of ciliary muscle to determine the objective refractive power in the eye.it is important to calculate full term visibility in accommodative esotropia and to prevent overcorrection in myopia. It is also useful in correcting errors in amblyopia and subjective refraction that face chaotic accommodation [2]. Retinoscopy is objective technique which is important to access the refractive errors, especially for infants and non-verbal. For an objective refraction to detect a possible failure of amblyopia this is an average value. The patient may develop amblyopia if the degree of anisometropia was important and not corrected [3]. Manual Retinoscopy is difficult and takes time even by an expert optometrist. On the other hand these things can be avoided with an auto-refractor that does not require a qualified person. Excessive accommodation effort is induced by those who use too much minus spectacles, because of this reason we do not overcorrect myopia that become troublesome [4]. Subjective refraction and cycloplegic refraction has become important measures to determine the visual status of younger patients. The cycloplegic refraction required more time to achieve complete cycloplegia. Cycloplegic Drops may cause discomfort like itching, redness, irritation. So, because of all these reasons nowadays, optometrist used auto refractor in place of cycloplegia. Auto refractor is used to access the objective refraction of children, clinical practice, visual assessment or Research purposes. Auto-refractor does not require a well train person [5]. To prevent accommodation, auto refractor has fogging technique. Some of the results made with respect to refractive errors and their ability to reconcile with one another. Children with overcorrection myopia have higher accommodation efforts that lead to progression in myopia [6]. When we compare the results of automatic refraction and cycloplegic Retinoscopy the values become spherical equivalent of the original values which are used for research purposes and individually, these spherical and cylindrical statements and their axis are modified into dioptric units that connect the sphere, cylinder and its axis [7]. Complete cycloplegia was used to access an accurate refractive error in adolescent less than 12 years of age, which is latent far sightedness, esotropia, poor fixation and children’s who are non-cooperative. For children of age 13 years refractive errors are determined by cycloplegia and self-refraction.  And for this purpose, several techniques have been performed between cycloplegic Retinoscopy and non-cycloplegic refraction [8]. Refractive error is pathology worldwide that affects large number of people and it is related to many eye diseases. In adults and infants cycloplegic refraction is important tool to measure refractive errors [9]. Cycloplegic drugs have many side effects like blurred vision, irritation in eyes and redness. Therefor some people are not satisfied after cycloplegic refraction because of problems due to cycloplegic drugs. But there is evidence that myopia may be over corrected and that long term vision could be corrected if refraction was achieved without cycloplegic drugs [10]. Accommodation improves slightly or completely depending upon the age of person. With dominant hyperopia and examination related accommodation results of automatic refractometer changes. That indicates greater myopic changes. Since the housing range is age dependent, its impact on refractor results increase with age and is significant for children. It includes training for childrens [11]. Significant errors are thought to be caused by refraction without cycloplegia in children. Myopia presents a change in refractive error due to frequent accommodation response that result in insufficient correction of hyperopia and overcorrection of myopia [12]. So, estimation of refractive error with cycloplegia is the method of choice to determine refractive error with in adolescent [13].  Accommodation, mainly in children, disturbs the equivalent of sphere performing an important part in calculation of refractive error. There young children and persons with more spherical power essential to confirm by retinoscopy. To identify the refractive error, refraction with cycloplegia is important. In children the power refractor is an applied and genuine hand-held auto refractor for the verification of refractive error [14, 15]. The objectives of this study were to check the effectiveness of objective refraction using auto refractor five minutes after in dark room with distance cycloplegic retinoscopy twenty minutes after of one drop of cyclopentolate (1%) in dimly illuminated room and to find out that autorefraction is more time saving and reliable method of refraction in children than cycloplegic retinoscopy.

2. MATERIALS AND METHODS

Comparative cross sectional study was conducted on patient with refractive errors from five to twenty (5-20) years of age. Patients with emmetropes, <5 & >20 years old patients, other ocular pathology, mentally retarded, and non-verbal children were excluded from study. Dependent variable was visual acuity. Independent variables were gender and age. Collage of Ophthalmology and Allied Vision Sciences were the place of study and study was conducted in 2019. Patients were visiting Eye Ward, Mayo Hospital, Lahore were included in study. Non- Probability Purposive sampling was used. Proportion of Cycloplegic refraction taken from previous study was 0.1322 and sample size was 34 patients. All the patients’ data was collected in mayo hospital eye ward. First after taking consent of all patient history was record. Then visual acuity recorded on LOGMAR chart. After sitting 5 mints in dark room auto-refraction was performed. Then cycloplegic retinosopy was performed after 20 minutes of one drop of cyclopentolate 1%. Then readings of both methods were compared with subjective refraction.

3. RESULTS AND DISCUSSION

Table 1 shows us the results from two famous tests of normality (Kolmogorov-Smirnov Test and the Shapiro-Wilk test). The Shapiro-Wilk Test is more correct for low sample size like less than 50, but it can also give results of large sample size up to 2000. So there for we are using the Shapiro-Wilk test for our numerical means of determination of normality. In the above table if the P-Value of the Shapiro-Wilk Test is greater than 0.05, the data is normal. Figure 1 shows that the total number of participants is 34. In which 4 with age of 6 years, 3 with age of 7 years,7 with age of 8 years,4 with age of 9 years,5 with age of 10 years,5 with age of 11 years and 6 with age of 12 years. Table 2 shows that the total number of participant is 34 in which 16 are male and 18 are females. Table 3 shows that out of 34 participants 20 have history of glasses and 14 have no history of glasses. Table 4 shows that right eye sphere with auto-refractor SD is 3.039, right eye sphere with retinoscopy SD is 2.948 and right eye sphere with subjective SD is 2.817.

Figure 1: Age distribution of age in patients (N = 34)

Table 1: Normality test results of study variables (N= 34)

Variables	Kolmogorov-Smirnova			Shapiro-Wilk
	Statistic	Df.	P-Value	Statistic	Df.	P-Value
Right eye sphere in dark	.231	15	.030	.855	15	.020
Left eye sphere in dark	.243	15	.018	.881	15	.049
Right eye cylinder in dark	.139	15	.200*	.941	15	.401
Left eye cylinder in dark	.130	15	.200*	.949	15	.515
Right eye axis in dark	.264	15	.006	.826	15	.008
Left eye axis in dark	.199	15	.114	.825	15	.008
Right eye sphere with Retino	.278	15	.003	.783	15	.002
Left eye sphere with Retino	.290	15	.001	.794	15	.003
Right eye cylinder with Retino	.116	15	.200*	.939	15	.369
Left eye cylinder with Retino	.113	15	.200*	.948	15	.495
Right eye axis with Retino	.254	15	.010	.832	15	.010
Left eye axis with Retino	.246	15	.015	.779	15	.002
Right eye sphere with sub ref	.280	15	.002	.825	15	.008
Left  eye sphere with sub ref	.280	15	.002	.789	15	.003
Right eye cylinder with sub ref.	.114	15	.200*	.959	15	.667
Left eye cylinder with sub ref.	.107	15	.200*	.948	15	.493
Right eye axis with sub ref.	.291	15	.001	.810	15	.005
Left eye axis with sub ref.	.257	15	.009	.840	15	.013
*. This is a lower bound of the true significance.
a. Lilliefors Significance Correction

Table 2: Gender distributions of patients

Variables	Frequency	Percent
Male	16	47.1
Female	18	52.9
Total	34	100.0

Table 3: Analysis of history of glasses usage

History of glasses usage	Frequency	Percent
Yes	20	58.8
No	14	41.2
Total	34	100.0

Table 4: Descriptive statistics of variables (Right eye sphere)

Category		N	Minimum	Maximum	Mean	S. Deviation
Auto in Dark	Right sphere	30	-7	6	.07	3.039
Retinoscopy	Right sphere	31	-7	6	.10	2.948
Subjective	Right sphere	29	-6	5	.17	2.817

Table 5 shows that left eye sphere with auto-refractor SD is 2.840, left eye sphere with retinoscopy SD is 3.254 and left eye sphere with subjective SD is 2.869.

Table 5: Descriptive statistics of variables (Left eye sphere)

Category		N	Minimum	Maximum	Mean	S. Deviation
Auto in Dark	Left sphere	33	-4	8	.58	3.039
Retinoscopy	Left sphere	32	-9	6	.16	2.948
Subjective	Left sphere	30	-8	5	.10	2.817

Table 6 shows that right eye cylinder with auto-refractor SD is 2.093, right eye cylinder with retinoscopy SD is 2.225 and right eye cylinder with subjective SD is 2.225. Table 7 shows that left eye cylinder with auto-refractor SD is 1.960, left eye cylinder with retinoscopy SD is 2.068 and left eye cylinder with subjective SD is 1.956.

Table 6: Descriptive statistics of variables (Right cylinder)

Variables	N	Mean	Std. Deviation	Std. Error	95% Confidence Interval for Mean		Minimum	Maximum
					Lower Bound	Upper Bound
Auto in Dark	33	-1.15	2.093	.364	-1.89	-.41	-6	3
Retinoscopy	27	-.89	2.225	.428	-1.77	-.01	-5	3
Subjective	23	-.96	2.225	.464	-1.92	.01	-5	3
Total	83	-1.01	2.150	.236	-1.48	-.54	-6	3

Table 7: Descriptive statistics of variables (Left cylinder)

Variables	N	Mean	Std. Deviation	Std. Error	95% Confidence Interval for Mean		Minimum	Maximum
					Lower Bound	Upper Bound
Auto in Dark	33	-.97	1.960	.341	-1.66	-.27	-5	3
Retinoscopy	28	-.86	2.068	.391	-1.66	-.06	-4	3
Subjective	25	-.92	1.956	.391	-1.73	-.11	-4	2
Total	86	-.92	1.972	.213	-1.34	-.50	-5	3

A study was performed on automatic refraction dark and cycloplegic retinoscopy after a drop of cyclopentolate. In 34 participants 34.53% of the population was female and 47% of male. This sample size was concluded with a specially designed formula [16]. When the auto-refraction and retinoscopy measurements were compared, the values were changed to SE for study and, individually, these spherical and cylindrical declarations and their axis are modified at a single point to obtain the eccentricity for each dimension in dioptric units which simultaneously connect the spherical, cylindrical and its axis of dimensions. Studies have shown that clinically significant impairment was greater in children under the age of 6. Although retraction is done due to the low level of collaboration and the high level of accommodation in children, these alterations do occur. In adult children, this can be improved, used to detect and correct refractive errors. In young people with mixed astigmatism, this should be checked with an automatic hand refractor and retinoscopy in the study, the spherical values showed variations between the three procedures [17]. Some previous studies show that retinoscopy after cycloplegia and autorefraction after cycloplegia could be useful screening tools for refractive error in offspring, but could not find any study indicating the consistency of autorefraction under cyclopentolate. In this study, autorefraction with cycloplegia provides good agreement with cycloplegic retinoscopy to find the type of refractive error. In our study, automatic refraction in the dark and cycloplegic refraction showed no significant difference in the three spherical, cylindrical and axial values. First, an automatic refraction is performed, then a retinoscopy then a subjective refraction. All three methods work on the same day [18]. Smith’s study shows us that the standard deviation of uncertainty in the calculation of refractive error is close to 0.3. Most of the uncertainty difference, which gives 95% autonomy, would be 0.6 diopters in the refractive error calculations. Refractive errors calculated with a difference of 0.25 diopters, appropriated a variation of more than 0.50 of the diopters of the spherical and cylindrical values as a clinically important change. Certain studies show that the automatic refractor produces a myopic refraction compared to subjective refraction. In contradiction, there is no significant association with cycloplegia. In previous studies, we obtained that the amounts of spherical equivalent and spherical power without cycloplegia by plusoptix A04 were compared with cycloplegic refraction. However, the application of the cycloplegic drug indicates an extended spherical equivalent, a cylindrical power and a spherical power calculated by plusoptix A09. In addition, the cylindrical power calculated by plusoptix A09 with and without cyclopentolate is greater [19]. A recent study that included screening children with refractive error with and without cycloplegia using retinomax K-plus 2 and plusopti X S08 and comparing it with cycloplegic retinoscopy, revealed that sensitivity advanced with cycloplegia because the accommodative element was excluded among the most young boys. Our study was conducted in children and compared objective refraction in the dark with cycloplegic and subjective refraction. The results do not show significant differences between the three procedures in terms of spherical, cylinder and axis values [20].

4. CONCLUSION AND RECOMMENDATIONS

In all the three methods of finding refractive status of patients the values of spherical, cylindrical and axis are statistically insignificant. The result of auto-refraction in darkness statistically shows same values to Retinoscopy and objective refraction. It is more satisfactory for parents as they have fears about side effects of cycloplegic drops.

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