Ocular hypotensive medications linked to IOL discoloration and opacification in long run

A recent laboratory study published in Eye by Tal Sharon and team of researchers aimed to assess the effect of hypotensive drugs on various characteristics of intraocular lenses (IOLs), including light absorbance, discoloration, opacification, and precipitate formation. The findings of this study shed light on potential interactions between these commonly used drugs and IOLs, providing valuable insights for clinicians and patients.

The study involved four different types of IOLs, including two hydrophilic-acrylic lenses (L1 and L2) and two hydrophobic-acrylic lenses (B1 and B2). These lenses were soaked in solutions containing different hypotensive drugs, including Timolol-maleate 0.5%, Dorzolamide 2%, Brimonidine-tartrate 0.2%, Latanoprost 0.005%,

Brimonidine-tartrate/Timolol-maleate 0.2%/0.5%, and Dorzolamide/Timolol-maleate 2%/0.5%. Non-treated IOLs and IOLs soaked in a balanced salt solution (BSS) served as controls. All treated lenses were subjected to heat at 82 degrees Celsius for 120 days.

The researchers employed four techniques to evaluate the IOLs: light microscopy imaging, light absorbance measurements at 550 nanometers, scanning electron microscopy (SEM) assessment, and energy dispersive X-ray spectrometry (EDX).

● The results of the study, which included a total of 98 IOLs, showed that the BSS-soaked IOLs appeared clear without any significant discoloration or precipitate formation.

● The light absorbance in these lenses was comparable to that of the non-soaked, non-heated IOLs.

● No calcium or phosphate was detected in either of these groups.

● Notable differences were observed in the light absorbance among the four types of treated IOLs.

● The specific hypotensive drops used had varying effects on light absorbance in the different IOLs.

● The gross examination revealed brown and yellow discoloration in IOLs soaked in Dorzolamide and Brimonidine-tartrate solutions, respectively. SEM analysis demonstrated precipitates that differed in size, morphology, and distribution depending on the specific combination of IOLs and drug solutions used.

● EDX analysis revealed the presence of calcium and phosphor in the majority of precipitates, while brown discoloured IOLs showed the presence of sulfur.

In conclusion, this in vitro study highlights the potential interactions between hypotensive drugs and IOLs, resulting in changes in light absorbance, discoloration, and precipitate formation. The findings emphasize the need for further investigation and awareness of these interactions, as they may have implications for patients undergoing treatment with hypotensive drugs and IOL implantation.

While this study provides valuable insights into the in vitro effects, it is important to note that further research is needed to understand the clinical significance of these findings. Clinicians should consider these factors when selecting appropriate hypotensive medications for

patients with IOLs, and additional studies should be conducted to validate the results in a real-world clinical setting.

Reference:

Sharon, T., Naftali Ben Haim, L., Rabinowicz, N., Kidron, D., Kidron, A., Ton, Y., Einan-Lifshitz, A., Assia, E. I., & Belkin, A. (2023). The effect of hypotensive drugs on intraocular lenses clarity. Eye, 37(8), 1696–1703. https://doi.org/10.1038/s41433-022-02225-w