Issue: January 2022
Disclosures: Agarwal and Narang report no relevant financial disclosures.
July 02, 2020
2 min read

Software system assists in analysis of pinhole pupilloplasty

Preoperative and postoperative assessments of PPP were performed with the Clinical Trial Suite.

Issue: January 2022
Disclosures: Agarwal and Narang report no relevant financial disclosures.
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Pinhole pupilloplasty has been described in cases with higher-order corneal aberrations to channelize the rays of light emerging from the central cornea, simultaneously barring and filtering the light from the irregular peripheral cornea.

Amar Agarwal
Amar Agarwal

Although any pupil reconstruction technique can be employed for performing pinhole pupilloplasty (PPP), we employed the single-pass four-throw technique due to the ease of doing the procedure as only a single pass from the anterior chamber to achieve a single knot. To achieve PPP, multiple attempts are needed to accomplish a pinhole pupil that is centered on the Purkinje 1 image emanating from the coaxial source of illumination of the surgical microscope (Figure 1).

PPP in a case with deep anterior lamellar keratoplasty
Figure 1. PPP in a case with deep anterior lamellar keratoplasty that had 12 D astigmatism. After DALK, cataract formation is seen, and the patient has vision of 6/60 on Snellen chart (a). Postoperative image at 6 months’ follow-up. Cataract removal with PPP was performed, and vision improved to 6/9 (b).

Source: Priya Narang, MS, and Amar Agarwal, MS, FRCS, FRCOphth

The efficacy of any surgical procedure is assessed by its applicability in various clinical situations in real-life performance. Therefore, the authors tried to study the effect of PPP in mesopic and photopic light conditions with various contrast levels. The Clinical Trial Suite (CTS, M&S Technologies) was deployed to perform the preoperative and postoperative assessments of all the cases that underwent PPP.

PPP performed in both eyes
Figure 2. Image depicts PPP performed in both eyes in a case of keratoconus (right eye, a; left eye, b).

The CTS consists of an android tablet that is synchronized with a laptop through Bluetooth connection. It calculates logMAR visual acuity and score values while offering standardization of luminance and contrast level as specified by ANSI, ISO and FDA/AAO task forces. The system can be calibrated for various viewing distances, and it presents random optotypes while assessing visual acuity and preventing memorization of the order. Numerous studies have validated the tests performed with the CTS. It has an automated ETDRS chart system for recording vision that is considered to be highly reliable. Every row has five letters, and the size of the letter changes in every row according to the logarithmic value. The distance between each letter is equal to the width of one letter, and the distance between lines is equal to the height of the letters in the lower row.

The visual parameters that were assessed were uncorrected and best corrected visual acuity, low contrast acuity at 10%, contrast sensitivity function and defocus curve. Favorable results were reported with PPP (Figure 2), suggesting that it can be employed for cases with higher-order corneal aberrations.