Matsya Purana — Description of Gomedaka and Puṣkara Dvīpas; the Lokāloka Boundary; Ocean Tide...
विपर्ययो न तेष्वस्ति एतत्स्वाभाविकं स्मृतम् आरोग्यं सुखबाहुल्यं मानसीं सिद्धिमास्थिताः //
viparyayo na teṣvasti etatsvābhāvikaṃ smṛtam ārogyaṃ sukhabāhulyaṃ mānasīṃ siddhimāsthitāḥ //
For them there is no reversal or decline; this is remembered as their natural condition—abundant health, a plenitude of happiness, and the attainment of inner (mental) perfection.
It implies a stable, non-declining condition where no “viparyaya” (reversal) occurs—suggesting an ideal order not subject to the disruptive changes associated with pralaya-like decay.
It frames well-being as a dharmic outcome: rulers and householders are urged (elsewhere in the Purana) to uphold dharma so society tends toward ārogya (public health), sukha (general welfare), and mental steadiness rather than instability.
No direct Vastu or ritual rule is stated; however, the verse supplies the desired result of right living and right rites—health, comfort, and mental clarity—which Vastu-aligned spaces and purificatory rituals are traditionally said to support.