Visual and Refractive Outcomes of Toric Implantable Phakic Contact Lens in Stable Keratoconus - A retrospective interventional cross-sectional study

TL;DR

Toric Implantable Phakic Contact Lenses improve vision in keratoconus patients after stabilization treatments, with good safety and effectiveness over one year.

Contribution

This is one of the first studies to analyze TIPCL outcomes across three keratoconus stabilization subgroups.

Findings

75.3% of eyes achieved more than 3 lines improvement in uncorrected distance visual acuity after one year.

TIPCL implantation showed statistically significant reductions in refractive errors across all subgroups.

Safety and efficacy indices of 0.77 and 1.20 were observed, comparable to prior studies on phakic IOLs.

Abstract

Refractive management in keratoconus is a challenging task. The study aimed to evaluate the results of Toric Implantable Phakic Contact Lenses in providing visual rehabilitation for patients with stable keratoconus after one year of primary procedures, including collagen cross-linking, topo-guided photorefractive keratectomy, and intracorneal ring segments.

This retrospective cross-sectional interventional study was conducted at a tertiary eye care hospital in South India. Sixty-four patients with 86 eyes were included, and all of them received Toric Implantable Phakic Contact Lens (TIPCL) implantation. All patients were subsequently divided into three subgroups: collagen cross-linking (CXL), intracorneal ring segments (INTACS+CXL), and Topographically Guided photorefractive keratectomy (TGPRK+CXL). Patients were followed up regularly for a period of one year.

We included data from 64 patients with 86 eyes, with an average age of 30.67 ± 7.96 years. Reduction in the mean spherical equivalent, sphere, and cylinder values was observed across all three subgroups, and the results were statistically significant. There was considerable improvement in uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (BDVA). At the end of one year, 75.3% of eyes achieved UDVA improvement of more than 3 lines. The average safety index was 0.77, and the efficacy index was 1.20.

TIPCL implantation proved to be a safe and effective option for correcting residual refractive error in keratoconus patients after stabilization procedures. Our results align with previous reports on phakic IOLs, demonstrating comparable safety and efficacy indices. The study emphasizes the importance of careful patient selection, as outcomes are strongly influenced by baseline refraction, corneal irregularity, and disease stability. While complications such as lens rotation, shallow anterior chamber, and cataract were rare, they emphasize the need for meticulous surgical planning and postoperative monitoring. Compared with existing literature, this is among the first studies to analyze outcomes across three stabilization subgroups, underscoring TIPCL as a viable, reversible option for patients with stable keratoconus.

The implantation of Toric Implantable Phakic Contact Lens (TIPCL) is a valuable option for visual rehabilitation in keratoconus patients.

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