Alterations in anterior segment dimensions in eyes with retinitis pigmentosa

Ocular biometry with swept-source optical coherence tomography-based optical biometer in Japanese patients with EYS-related retinitis pigmentosa: a retrospective study

Background

This study aimed to identify the features of ocular biometry in patients with EYS-related retinitis pigmentosa using IOLMaster 700.

Methods

We retrospectively reviewed the medical records of patients with retinitis pigmentosa. Patients with records of the following were included: (1) ocular biometry measurements using the IOLMaster 700 and (2) genetic diagnostic tests. Axial length, keratometry, anterior chamber depth, aqueous depth, lens thickness, central corneal thickness (CCT), and corneal diameter (white to white) measurements were extracted. Based on keratometry measurements, (1) standard keratometric astigmatism, (2) posterior corneal astigmatism, and (3) total corneal astigmatism were obtained. Demographics and biometric parameters were compared between patients with EYS-related retinitis pigmentosa and other patients with retinitis pigmentosa.

Results

A total of 86 eyes of 44 patients (23 females and 21 males; mean age: 47.7 years) with retinitis pigmentosa were included. Of these, 18 were identified as having EYS variants. CCT was significantly thinner (P < 0.001) and the posterior corneal curvature at the steepest meridian was significantly smaller (P = 0.024) in patients with EYS-related retinitis pigmentosa than in other patients with retinitis pigmentosa. The magnitudes of all corneal astigmatism measurements was higher in patients with EYS-related RP, although these differences were not statistically significant.

Conclusion

Patients with EYS-related retinitis pigmentosa had unique features in ocular biometry, such as thinner central corneal thickness and smaller posterior corneal curvature radius at the steepest meridian compared with other patients with retinitis pigmentosa. The findings suggest that patients with retinitis pigmentosa have different ocular dimension features among the different causative genes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02284-3.

The architecture of the mouse ciliary processes and their changes during retinal degeneration

In contrast to most mammalian species, the ciliary processes in the mouse eye form an irregular pattern. Different strains were studied using scanning electron microscopy. The ciliary processes of C57BL/6J animals showed quadrant-specific characteristics: in the superior quadrant, large and radial oriented processes were present. In the inferior quadrant, the processes were small but still mainly radial oriented. In the temporal quadrant, the processes showed a radial, longitudinal course, some being L-shaped. In the nasal quadrant, few processes were oriented longitudinal. In DBA/2 animals, the processes were shorter and the radial orientation less developed. NMRI animals showed the shortest processes with no increase towards the superior quadrant. Additionally we investigated age-related changes in the ciliary processes of Pde6b(rd1) mice, which develop retinal degeneration. In C57BL/6J mice, the ciliary body shape, size and architecture was comparable between 3 and 10 months of age, but showed a mild shortening of the pars plicata in the temporal, inferior and nasal quadrants in animals older than 20 months of age. The parameters of the ciliary body in 3 months old Pde6b(rd1) mice were comparable to those of age-matched C57BL/6J mice. Pde6b(rd1) mice 10 months old revealed significant shortening of the total width of the ciliary body and of the length of ciliary processes in all quadrants. The shape and architecture of the ciliary processes remained preserved.

Morphological changes in the anterior segment of the Abyssinian cat eye with hereditary rod-cone degeneration

PURPOSE

The purpose of this study was to investigate morphological changes of the anterior segment of the eye in Abyssinian cats with progressive rod-cone degeneration and to correlate them with blood flow data obtained in the same animals.

METHODS

Sections of the left eyes of six normal cats and of eight cats with different stages of hereditary retinal degeneration were prepared for transmission and scanning electron microscopy. Tangential and sagittal sections were also stained with antibodies against substance P, tyrosine hydroxylase, panneuronal marker PGP9.5, nitric oxide synthase, synaptophysin, and smooth muscle alpha-actin.

RESULTS

In Abyssinian cats with hereditary rod-cone degeneration, significant changes were observed in the iris consisting of irregularities in the vascular wall of smaller arteries without changes in their innervation pattern. The ciliary processes were shorter than in normal cats, and their structure appeared more compact and retracted. Slight changes were also observed in the anterior part of the ciliary epithelium. The anterior chamber angle region did not appear to be affected.

CONCLUSIONS

Clear morphological correlations to the physiological blood flow data were observed in the anterior eye segment, pointing not only to functional but also morphological vascular abnormalities in this animal model for retinitis pigmentosa.