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Clear-cornea cataract surgery: pupil size and shape changes, along with anterior chamber volume and depth changes. A Scheimpflug imaging study.

Kanellopoulos AJ, Asimellis G - Clin Ophthalmol (2014)

Bottom Line: Pupil size analysis showed that the horizontal pupil diameter was reduced by -0.27±0.22 mm (-9.7%; P=0.001) and the vertical pupil diameter was reduced by -0.32±0.24 mm (-11%; P<0.001).Pupil eccentricity was reduced by -39.56%; P<0.001.These changes appear to be more significant with increasing patient age.

View Article: PubMed Central - PubMed

Affiliation: Laservision.gr Eye Institute, Athens, Greece ; New York University School of Medicine, New York, NY, USA.

ABSTRACT

Purpose: To investigate, by high-precision digital analysis of data provided by Scheimpflug imaging, changes in pupil size and shape and anterior chamber (AC) parameters following cataract surgery.

Patients and methods: The study group (86 eyes, patient age 70.58±10.33 years) was subjected to cataract removal surgery with in-the-bag intraocular lens implantation (pseudophakic). A control group of 75 healthy eyes (patient age 51.14±16.27 years) was employed for comparison. Scheimpflug imaging (preoperatively and 3 months postoperatively) was employed to investigate central corneal thickness, AC depth, and AC volume. In addition, by digitally analyzing the black-and-white dotted line pupil edge marking in the Scheimpflug "large maps," the horizontal and vertical pupil diameters were individually measured and the pupil eccentricity was calculated. The correlations between AC depth and pupil shape parameters versus patient age, as well as the postoperative AC and pupil size and shape changes, were investigated.

Results: Compared to preoperative measurements, AC depth and AC volume of the pseudophakic eyes increased by 0.99±0.46 mm (39%; P<0.001) and 43.57±24.59 mm(3) (36%; P<0.001), respectively. Pupil size analysis showed that the horizontal pupil diameter was reduced by -0.27±0.22 mm (-9.7%; P=0.001) and the vertical pupil diameter was reduced by -0.32±0.24 mm (-11%; P<0.001). Pupil eccentricity was reduced by -39.56%; P<0.001.

Conclusion: Cataract extraction surgery appears to affect pupil size and shape, possibly in correlation to AC depth increase. This novel investigation based on digital analysis of Scheimpflug imaging data suggests that the cataract postoperative photopic pupil is reduced and more circular. These changes appear to be more significant with increasing patient age.

No MeSH data available.


Related in: MedlinePlus

Graphical illustration of preoperative (left) and postoperative (right) anterior segment indicating the increase in anterior chamber volume and depth.Note: The increased freedom of movement allowing for a smaller pupil diameter is a possible contributing factor to the findings in this work of a reduced pupil diameter and more circular shape.
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f5-opth-8-2141: Graphical illustration of preoperative (left) and postoperative (right) anterior segment indicating the increase in anterior chamber volume and depth.Note: The increased freedom of movement allowing for a smaller pupil diameter is a possible contributing factor to the findings in this work of a reduced pupil diameter and more circular shape.

Mentions: The present study suggests a statistically significant alteration in pupil size and shape following cataract surgery: the postoperative pupil size reduction averaged between −11% and −13%. In addition, pupil eccentricity was substantially reduced (−39%). These pupil size changes may be related to the increased AC depth and volume following the extraction of the bulky crystalline lens (Figure 5) – average thickness of 4.4 mm – and replacement with a thin IOL – thickness often <1 mm.30 The reduced IOL volume may allow for more freedom of movement of the constrictor iris muscles, thus possibly enabling their full extent. It is also likely that a preoperative reduction of iris movement constraints, possibly induced by the narrow spatial allowance due to the crystalline lens intumescence as it develops into a cataract, may be related to the asymmetries in pupil shape relating to the measured preoperative eccentricity. The radical reduction (or even elimination) of such constrains may also be a contributing factor to the more circular (less eccentric) pupil size following cataract removal surgery.


Clear-cornea cataract surgery: pupil size and shape changes, along with anterior chamber volume and depth changes. A Scheimpflug imaging study.

Kanellopoulos AJ, Asimellis G - Clin Ophthalmol (2014)

Graphical illustration of preoperative (left) and postoperative (right) anterior segment indicating the increase in anterior chamber volume and depth.Note: The increased freedom of movement allowing for a smaller pupil diameter is a possible contributing factor to the findings in this work of a reduced pupil diameter and more circular shape.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4216028&req=5

f5-opth-8-2141: Graphical illustration of preoperative (left) and postoperative (right) anterior segment indicating the increase in anterior chamber volume and depth.Note: The increased freedom of movement allowing for a smaller pupil diameter is a possible contributing factor to the findings in this work of a reduced pupil diameter and more circular shape.
Mentions: The present study suggests a statistically significant alteration in pupil size and shape following cataract surgery: the postoperative pupil size reduction averaged between −11% and −13%. In addition, pupil eccentricity was substantially reduced (−39%). These pupil size changes may be related to the increased AC depth and volume following the extraction of the bulky crystalline lens (Figure 5) – average thickness of 4.4 mm – and replacement with a thin IOL – thickness often <1 mm.30 The reduced IOL volume may allow for more freedom of movement of the constrictor iris muscles, thus possibly enabling their full extent. It is also likely that a preoperative reduction of iris movement constraints, possibly induced by the narrow spatial allowance due to the crystalline lens intumescence as it develops into a cataract, may be related to the asymmetries in pupil shape relating to the measured preoperative eccentricity. The radical reduction (or even elimination) of such constrains may also be a contributing factor to the more circular (less eccentric) pupil size following cataract removal surgery.

Bottom Line: Pupil size analysis showed that the horizontal pupil diameter was reduced by -0.27±0.22 mm (-9.7%; P=0.001) and the vertical pupil diameter was reduced by -0.32±0.24 mm (-11%; P<0.001).Pupil eccentricity was reduced by -39.56%; P<0.001.These changes appear to be more significant with increasing patient age.

View Article: PubMed Central - PubMed

Affiliation: Laservision.gr Eye Institute, Athens, Greece ; New York University School of Medicine, New York, NY, USA.

ABSTRACT

Purpose: To investigate, by high-precision digital analysis of data provided by Scheimpflug imaging, changes in pupil size and shape and anterior chamber (AC) parameters following cataract surgery.

Patients and methods: The study group (86 eyes, patient age 70.58±10.33 years) was subjected to cataract removal surgery with in-the-bag intraocular lens implantation (pseudophakic). A control group of 75 healthy eyes (patient age 51.14±16.27 years) was employed for comparison. Scheimpflug imaging (preoperatively and 3 months postoperatively) was employed to investigate central corneal thickness, AC depth, and AC volume. In addition, by digitally analyzing the black-and-white dotted line pupil edge marking in the Scheimpflug "large maps," the horizontal and vertical pupil diameters were individually measured and the pupil eccentricity was calculated. The correlations between AC depth and pupil shape parameters versus patient age, as well as the postoperative AC and pupil size and shape changes, were investigated.

Results: Compared to preoperative measurements, AC depth and AC volume of the pseudophakic eyes increased by 0.99±0.46 mm (39%; P<0.001) and 43.57±24.59 mm(3) (36%; P<0.001), respectively. Pupil size analysis showed that the horizontal pupil diameter was reduced by -0.27±0.22 mm (-9.7%; P=0.001) and the vertical pupil diameter was reduced by -0.32±0.24 mm (-11%; P<0.001). Pupil eccentricity was reduced by -39.56%; P<0.001.

Conclusion: Cataract extraction surgery appears to affect pupil size and shape, possibly in correlation to AC depth increase. This novel investigation based on digital analysis of Scheimpflug imaging data suggests that the cataract postoperative photopic pupil is reduced and more circular. These changes appear to be more significant with increasing patient age.

No MeSH data available.


Related in: MedlinePlus