The mean age of the participants was 23.62 ± 4.44 years. Preoperative status of the patients was as follows: mean spherical equivalent (SE) was − 7.18 ± 2.91 D, mean preoperative UDVA was 1.04 ± 0.55 LogMAR, mean CDVA was 0.01 ± 0.02, mean centre cornea thickness (CCT) was 524.35 ± 37.31 mm, mean WTW was 11.60 ± 0.38mm. Postoperative status of the patients in three months was as follows: mean UDVA was − 0.10 ± 0.06 LogMAR (Table 1). Mean QoV for day and night was 9.34 ± 0.76 and 8.58 ± 1.29 respectively.
Table 1
Parameters Mean ± SD |
Age (years) | 23.62 ± 4.44 |
Sex | 28 males (53%)/ 25 females (47%) |
Pre surgery UDVA | 1.04 ± 0.55 |
ACD (mm) | 3.31 ± 0.25 |
SE (diopter) | -7.18 ± 2.91 |
K1 (diopter) | 43.19 ± 1.37 |
K2 (diopter) | 44.56 ± 1.36 |
CTT (mm) | 524.35 ± 37.31 |
WTW (mm) | 11.60 ± 0.38 |
IOP (mmHg) | 13.88 ± 2.64 |
ICL diameter (mm) | 13.03 ± 0.35 |
UDVA: uncorrected visual acuity, LogMAR: logarithm of the minimum angle of resolution, ACD: anterior chamber depth, SE: spherical equivalent, CCT: central corneal thickness, WTW: white-to-white, IOP: intraocular pressure, ICL: implantable collamer lens. |
Pupil size assessment: Pre-operative mean MPS and mean PPS was 6.75 ± 0.84mm (range: 4.73mm to 9.14mm) and 4.57 ± 0.74mm (range: 2.92mm to 5.84mm) respectively. At 3-month following surgery, mean MPS and mean PPS was 6.59 ± 0.79mm (range: 4.66mm to 8.31mm) and 4.61 ± 0.74mm (range: 2.96mm to 5.86mm) respectively. Pre-operative and the post-operative MPS (P < 0.001, t = 8.344) and pre-operative and the post-operative PPS (P < 0.001, t =-10.860) were both significantly different.
Prevalence and distribution of dysphotopsia: post-operatively, dysphotopsia symptoms were assessed and the highest score that could be achieved by a patient was 9 and lowest was 0. The mean score of total glare score was 0.28 ± 1.21 (range: 0 to 6), total halo score was 2.15 ± 1.78 (range: 0 to 7), total starburst score was 0.47 ± 1.19 (range: 0 to 4), total hazy score was 0.30 ± 1.03 (range: 0 to 5), total blurred score was 0.34 ± 1.18 (range: 0 to 6), total double vision score was 0.23 ± 0.80 (range: 0 to 3), total fluctuation score was 0.09 ± 0.30 (range: 0 to 1), total focus score was 0.17 ± 0.78 (range: 0 to 5), total depth perception score was 0.08 ± 0.38 (range: 0 to 2), in this study we didn’t find any patients experienced distortion (Table 2). Mean and stand deviation score of frequency, severity, and influence of visual symptoms (including glare, halo, starbursts, hazy vision, blurred vision, experience distortion, double or multiple images, focusing difficulties, depth perception) is shown in histograms of Figs. 1, 2, 3 and 4 respectively.
Table 2
Assessment of pupil size and quality of vision questionnaire items
Variables | Mean ± SD | Minimum | Maximum |
Mesopic pupil size (mm) | 6.59 ± 0.79 | 4.66 | 8.31 |
Photopic pupil size (mm) | 4.61 ± 0.74 | 2.96 | 5.86 |
QoV at night (0–10) | 8.58 ± 1.29 | 5.00 | 10.00 |
QoV at day (0–10) | 9.34 ± 0.76 | 8.00 | 10.00 |
Total glare score (0–9) | 0.28 ± 1.21 | 0.00 | 6.00 |
Total halo score (0–9) | 2.15 ± 1.78 | 0.00 | 7.00 |
Total starburst (0–9) | 0.47 ± 1.19 | 0.00 | 4.00 |
Total hazy score (0–9) | 0.30 ± 1.03 | 0.00 | 5.00 |
Total blurred score (0–9) | 0.34 ± 1.18 | 0.00 | 6.00 |
Total distortion score (0–9) | 0.00 ± 0.00 | 0.00 | 0.00 |
Total double vision (0–9) | 0.23 ± 0.80 | 0.00 | 3.00 |
Total fluctuation score (0–9) | 0.09 ± 0.30 | 0.00 | 1.00 |
Total focus score (0–9) | 0.17 ± 0.78 | 0.00 | 5.00 |
Total depth perception score (0–9) | 0.08 ± 0.38 | 0.00 | 2.00 |
The impact of pupil size upon QoV: MPS negatively correlated with QoV at day time (Rs = -0.413*, P = 0.001) (Fig. 5). PPS negatively correlated with QoV at nighttime (Rs = -0.426* P = 0.001) (Fig. 6).
Impact of pupil size upon dysphotopsia: PPS significantly correlated with “halo” (Rs = 0.568*, P < 0.001), and “blurred vision” (Rs = 0.243*, P = 0.04). However, PPS had no significant correlation with “glare” (Rs = 0.169, P = 0.113), “starburst” (Rs = 0.115, P = 0.207),“hazy vision” (Rs = 0.115, P = 0.207), “multiple images” (Rs = 0.198, P = 0.077), “fluctuation in vision” (Rs= 0.004, P = 0.488), “focusing difficulties” (Rs = 0.118, P = 0.199), “difficulty judging distance or depth perception” (Rs = 0.181, P = 0.097). While assessing MPS, significant correlation was found with “halo” (Rs = 0.624*, P < 0.001), “starburst” (Rs = 0.233*, P = 0.046), and “focusing difficulties” (Rs = 0.27*, P = 0.025). Furthermore, MPS was found to have no significant correlation with “glare” (Rs = 0.022, P = 0.437), “hazy vision” (Rs=0.169, P = 0.114), “blurred vision” (Rs =0.069, P = 0.311), “multiple images” (Rs=0.226, P = 0.051), “fluctuation in vision” (Rs= 0.127, P = 0.183), “difficulty judging distance or depth perception” (Rs = 0.042, P = 0.382). (Table 3.)
Table 3
Impact of pupil size upon dysphotopsia
Variables | Total glare score | Total halo score | Total starburst score | Total hazy score | Total blur score | Total distortion score | Total double score | Total fluctuation score | Total focus score | Total depth score |
Photopic (mm) | 0.169 | .568** | 0.115 | 0.022 | .243* | -- | 0.198 | 0.004 | 0.118 | 0.181 |
P-value | 0.113 | < 0.001 | 0.207 | 0.437 | 0.04 | -- | 0.077 | 0.488 | 0.199 | 0.097 |
Mesopic (mm) | 0.022 | .624** | .233* | 0.169 | 0.069 | -- | 0.226 | -0.127 | .270* | -0.042 |
P-value | 0.437 | < 0.001 | 0.046 | 0.114 | 0.311 | -- | 0.051 | 0.183 | 0.025 | 0.382 |
mm: milimeter; * Correlation is significant at the 0.05 level; ** Correlation is significant at the 0.01 level. |
Additionally, this study compared mean QoV for and night in different incrementally increasing pupil groups. Night QoV was found to be significantly different among groups (P = 0.02*, F = 3.234), and the pupil size from 4.00 to 4.99 mm was found to achieved better mean QoV at night (mean QoV: 10 ± 0.00). While QoV at daytime was not found to be significantly different between different PPS groups. (Table 4).
Table 4
Comparison of QoV in pupil groups
Photopic pupil (mm) |
| Group A (2-2.99) | Group B (3-3.99) | Group C (4-4.99) | Group D (5-5.99) | Group E (6-6.99) | Group F (7-7.99) | Group G (8-8.99) | P-value | F value |
Mean Total QoV day score (0–10) | 10.00 | 9.64 | 9.39 | 9.06 | 0.00 | 0.00 | 0.00 | 0.166 | 1.768 |
±SD | 0.00 | 0.67 | 0.72 | 0.80 | 0.00 | 0.00 | 0.00 |
Mesopic pupil (mm) |
| Group A (2-2.99) | Group B (3-3.99) | Group C (4-4.99) | Group D (5-5.99) | Group E (6-6.99) | Group F (7-7.99) | Group G (8-8.99) | P-value | F value |
Mean Total QoV night score (0–10) | 0.00 | 0.00 | 10.00 | 9.00 | 8.56 | 8.15 | 6.67 | 0.02* | 3.234 |
±SD | 0.00 | 0.00 | 0.00 | 0.82 | 1.34 | 1.14 | 0.58 |
mm: millimeter; Correlation is significant at the 0.05 level; ** Correlation is significant at the 0.01 level. |